External ID: OPRM1-OPRD1_AG_LUMI_1536_1X%ACT PRUN

Protocol: Assay Overview:

The purpose of this assay is to identify compounds that activate heterodimer formation between the mu (OPRM1) and delta (OPRD1) opioid receptors, resulting in membrane recruitment of beta-arrestin. The assay monitors GPCR-beta-arrestin proximity using low affinity fragment complementation of beta-galactosidase (beta-gal). This assay employs U2OS cells which express OPRD1, OPRM1 fused to a beta-gal peptide fragment (enzyme donor), and beta-arrestin fused to the complementary beta-gal fragment (enzyme acceptor). Cells are incubated with test compound, followed by measurement of well luminescence. As designed, compounds that induce formation of OPRD1 homodimers or OPRM1-OPRD1 (Mu-Delta) heterodimers will cause beta-arrestin recruitment, resulting in reconstitution of the beta-gal holoenzyme. The reconstituted holoenzyme can then catalyze the hydrolysis of a substrate which yields a chemiluminescent signal, resulting in increased well luminescence. Deltorphin B will be used as the high (100% RLU) control for agonists, and wells containing cells treated with DMSO will be used as the low (0% RLU) control. Compounds were tested in singlicate at a final nominal concentration of 9.3 uM.

Protocol Summary:

The U2OS-OPRM1-OPRD1 (Mu-Delta) cell line was routinely cultured in T-175 sq cm flasks at 37 C and 95% relative humidity (RH). The growth media consisted of a 1:1 mixture of Ham's F-12 Nutrient Media (F-12) and Dulbecco's Modified Eagle Media (DMEM) supplemented with 10% v/v heat-inactivated certified fetal bovine serum, 25 mM HEPES, 250 ug/mL Geneticin, 250 ug/mL Hygromycin B, 0.25 ug/mL Puromycin and 1X antibiotic mix (penicillin, streptomycin, and neomycin).

The day before the assay 1000 cells in 3 uL of cell plating media were seeded into each well of 1536 well microtiter plates and allowed to incubate at 37 C, 5% CO2, and 95 % RH for 23 hours. Next, 28 nL of test compound in DMSO, Deltorphin B (0.9 uM final concentration) in DMSO, or DMSO alone were dispensed to the appropriate wells. The plates were then incubated for 3 hours at 37 C, 5% CO2, and 95 % RH. The assay was started by adding 2 uL of PathHuntertrade mark reagent (prepared according to the manufacturer's protocol); followed by 1 hour incubation at room temperature. Then, Well Luminescence was read on the ViewLux plate reader

The percent activation for each compound was calculated as follows:

% Activation = ( ( Ratio_Test_Compound - Median_Ratio_Low_Control ) / ( Median_Ratio_High_Control - Median_Ratio_Low_Control ) ) * 100

Where:

High_Control is defined as wells containing cells, Deltorphin B and DMSO.
Test_Compound is defined as wells containing cells, test compounds and DMSO.
Low_Control is defined as wells containing cells and DMSO.

A mathematical algorithm was used to determine nominally activating compounds in the primary screen. Two values were calculated: (1) the average percent activation of all compounds tested, and (2) three times their standard deviation. The sum of these two values was used as a cutoff parameter, i.e. any compound that exhibited greater % activation than the cutoff parameter was declared active.

PubChem Activity Outcome and Score:

The reported PubChem Activity Score has been normalized to 100% observed primary activation. Negative % activation values are reported as activity score zero.

The PubChem Activity Score range for active compounds is 100-2, and for inactive compounds 2-0.

List of Reagents:

PathHuntertrade mark B-arrestin recruitment assay, containing the U2OS OPRM1 OPRD1 Beta-arrestin cell line; PathHunter Detection Kit (DiscoveRx, part, 93-0558C3)
Ham's F-12 media (Invitrogen, part 11765-054)
DMEM media (Invitrogen, part 11995-073)
Detachin (Genlantis, part T100100)
Heat Inactivated Fetal Bovine Serum (Invitrogen, part 10082-147)
Puromycin (Invitrogen, part A11138-02)
Hygromycin B (Invitrogen, part 10687-010)
Geneticin (Invitrogen, part 10131-027)
100X Penicillin-Streptomycin-Neomycin mix (Invitrogen, part 15640-055)
T-175 tissue culture flasks (Nunc, part 159910)
Agonist: Deltorphin B (Anaspec, part 62683)
1536-well plates (Greiner, part 789173)

Comment: Due to the increasing size of the MLPCN compound library, this assay may have been run as two or more separate campaigns, each campaign testing a unique set of compounds. All data reported were normalized on a per-plate basis. Possible artifacts of this assay can include, but are not limited to: dust or lint located in or on wells of the microtiter plate, and compounds that modulate well fluorescence. All test compound concentrations reported above and below are nominal; the specific test concentration(s) for a particular compound may vary based upon the actual sample provided by the MLSMR.

External ID: CHRM1_AG_FLUO8_1536_1X%ACT PRUN

Protocol: Assay Overview:

The purpose of this assay is to identify compounds that act as agonists of the human M1 muscarinic receptor (CHRM1; M1). In this assay, CHO-K1 cells stably expressing human M1 are loaded, intracellularly with the calcium indicator dye, Fluo-8, followed by treatment with agonist control or test compounds. As designed, compounds that act as CHRM1 agonists will increase intracellular calcium mobilization, resulting in increased relative fluorescence of the indicator dye and well fluorescence. Compounds are tested in singlicate at a final nominal concentration of 3 uM.

Protocol Summary:

The CHO-hM1 cell line was routinely cultured in T-175 sq cm flasks at 37 C and 95% relative humidity (RH). The growth media consisted of Ham's F-12 Nutrient Media (F-12) supplemented with 10% v/v heat-inactivated qualified fetal bovine serum, 20 mM HEPES, 50 ug/mL Geneticin, and 1X antibiotic mix (penicillin and streptomycin).

The day before the assay 3000 cells in 3 uL of growth media were seeded into each well of 1536 well microtiter plates and allowed to incubate at 37 C, 5% CO2, and 95 % RH for 17-24 hours. Next, 2 uL of the fluorogenic Fluo-8 intracellular calcium indicator mixture (prepared according to the manufacturer's protocol) was added to each well. Plates were then incubated for 1 hour at 37 C, 5% CO2, and 95 % RH, followed by 30 minute incubation at room temperature. Then, 15 nL of test compound in DMSO were dispensed to appropriate wells. The assay was started by performing a basal read of plate fluorescence (470-495 nm excitation and 515-575 nm emission) for 5 seconds on the FLIPR Tetra (Molecular Devices). Then a real time fluorescence measurement was immediately performed for the remaining 140 seconds of the assay. A ratio for each well was calculated to normalize assay data, according to the following mathematical expression:

Ratio = I_Max / I_Min

Where:

I_Max represents the maximum measured fluorescence emission intensity over the 140 second read.
I_Min represents the minimum (basal) measured fluorescence emission intensity before compound was added.

The percent activation was calculated from the median ratio as follows:

%_Activation = ( ( Ratio_Test_Compound - Median_Ratio_Low_Control ) / ( Median_Ratio_High_Control - Median_Ratio_Low_Control ) ) * 100

Where:

Test_Compound is defined as wells containing test compound.
Low_Control is defined as wells containing DMSO.
High_Control is defined as wells containing Acetylcholine (EC100) and DMSO.

PubChem Activity Outcome and Score:

A mathematical algorithm was used to determine nominally activating compounds in the primary screen. Two values were calculated for each assay plate: (1) the average percent activation of test compound wells and (2) three times their standard deviation. The sum of these two values was used as a cutoff parameter for the entire run, i.e. any compound that exhibited greater % activation than the entire screen's cutoff parameter was declared active.

The reported PubChem Activity Score has been normalized to 100% observed primary activation. Negative % activation values are reported as activity score zero.

The PubChem Activity Score range for active compounds is 100-1, and for inactive compounds 1-0.

List of Reagents:

Cell line: Chinese Hamster Ovary (CHO) cells containing hM1 receptor; (Conn Lab)
Calcium sensitive dye: Fluo-8 No Wash Calcium Assay Kit; (AAT Bioquest, part 36316)
Growth media: Ham's F-12; 10% FBS, 20mM HEPES, 50 ug/mL G418
Assay media: Ham's F-12, 10% FBS, 20 mM HEPES
Assay plates: Aurora black/clear 1536well FLIPR plate; (Aurora, part 00019326)
Probenecid: 250 mM (pH 8.0); (Sigma P8761)
Agonist: Acetylcholine (50 mM stock in water); Sigma A9187

Comment: Due to the increasing size of the MLPCN compound library, this assay may have been run as two or more separate campaigns, each campaign testing a unique set of compounds. All data reported were normalized on a per-plate basis. Possible artifacts of this assay can include, but are not limited to: dust or lint located in or on wells of the microtiter plate, and compounds that modulate well fluorescence. All test compound concentrations reported above and below are nominal; the specific test concentration(s) for a particular compound may vary based upon the actual sample provided by the MLSMR.

External ID: TargetID_659_CEMA

Protocol: Black, standard capacity streptavidin-coated 384-well plates (Pierce 15407) were first washed with 50 L of phosphate buffer (100 mM, pH 7.0; PB7) three times using a Biotek 405 ELX plate washer. Subsequently, 5 L of biotinylated pre-miRNA substrate (500 nM final) was dispensed into the plate using a Multidrop Combi Reagent Dispenser (Thermo Scientific). Plates were then centrifuged for 1 min at 1,000 RPM (223 g), sealed with plate tape, and incubated overnight at 4 C. The following morning, plates were washed three times with 50 L of PB7, followed by the addition of 5 L of Dicer digest buffer (20 mM Tris, 12 mM NaCl, 2.5 mM MgCl2, 1 mM fresh DTT, and 4.5% DMSO) and centrifugation. Compounds (50 nL of 5 mM DMSO stock, 25 M final) were then added into the sample wells using a Sciclone (Caliper) liquid handler with V&P pintool; the same volume of DMSO was added to the control wells. The plates were incubated at 25 C for 15 min before addition of 5 L of digest buffer containing 217 g/nL Dicer (108 g/mL Dicer, 5% glycerol and 0.01% Triton X-100 final, excess with respect to pre-miRNA). For the positive control wells, digest buffer without Dicer was added. The plates were centrifuged again and resealed before being placed in a 37 C incubator for 5 h. After Dicer cleavage, plates were washed three times with 50 L of PB7. mTet-HRP in PB7 (10 L, 750 nM final) was then dispensed into each well. The plates were subsequently centrifuged, sealed, and incubated at 25 C for 2 h. Plates were then washed three times with 50 L of wash buffer (2 mM imidazole, 260 mM NaCl, 0.5 mM EDTA, 0.1% Tween-20, pH 7.0), followed by washing three additional times with 50 L of PB7. Finally, SuperSignal West Pico (25 L; Pierce) was added, the plates were incubated at 25 C for 5 min, and chemiluminescence signal was detected using a PHERAstar plate reader using LUM plus module (BMG Labtech).

Comment: The activity outcome is based on a Z-score (number of standard deviations from the negative control mean) of 3 or higher on at least 50% times that the sample was screened.

For instance, if the sample was screened in n=4 runs, it would be considered active only if it had a Z-score of 3 or above in at least 2 runs.

External ID: CHRM1_PAM_FLUO8_1536_1X%ACT PRUN

Protocol: Assay Overview:

The purpose of this assay is to identify compounds that act as positive allosteric modulators (PAMs) and increase activity of the human M1 muscarinic receptor (CHRM1; M1) in cells pre-treated with a known agonist. In this assay, CHO-K1 cells stably expressing human M1 are loaded with the Fluo-8 calcium indicator dye, followed by addition of test compounds and subsequent treatment with the activator acetylcholine at a concentration that results in 20% activation (EC20). As designed, compounds that act as CHRM1 PAMs will increase calcium mobilization, resulting in increased intracellular calcium and relative fluorescence of the indicator dye beyond that of the EC20 of acetylcholine. Compounds are tested in singlicate at a final nominal concentration of 3 micromolar.

Protocol Summary:

The CHO-hM1 cell line was routinely cultured in T-175 sq cm flasks at 37 degrees C and 95% relative humidity (RH). The growth media consisted of Ham's F-12 Nutrient Media (F-12) supplemented with 10% v/v heat-inactivated qualified fetal bovine serum, 20 mM HEPES, 50 micrograms/mL Geneticin, and 1X antibiotic mix (penicillin and streptomycin).

The day before the assay 3000 cells in 3 microliters of growth media were seeded into each well of 1536 well microtiter plates and allowed to incubate at 37 degrees C, 5% CO2, and 95 % RH for 17-24 hours. Next, 2 microliters of the fluorogenic Fluo-8 intracellular calcium indicator mixture (prepared according to the manufacturer's protocol) was added to each well. Plates were then incubated for 1 hour at 37 degrees C, 5% CO2, and 95 % RH, followed by 30 minute incubation at room temperature. Then, 15 nL of test compound in DMSO were transferred to appropriate wells. The assay was started by performing a basal read of plate fluorescence (470-495 nm excitation and 515-575 nm emission) for 5 seconds on the FLIPR Tetra (Molecular Devices) prior to all wells being treated with an EC20 concentration of acetylcholine. Then a real time fluorescence measurement was immediately performed for the remaining 140 seconds of the assay. A ratio for each well was calculated to normalize assay data, according to the following mathematical expression:

Ratio = I_Max / I_Min

Where:

I_Max represents the maximum measured fluorescence emission intensity over the 140 second read and;
I_Min represents the minimum (basal) measured fluorescence emission intensity before compound was added.

The percent activation was calculated from the median ratio as follows:

% Activation = ( ( Ratio_Test_Compound - Median_Ratio_Low_Control ) / ( Median_Ratio_High_Control - Median_Ratio_Low_Control ) ) * 100

Where:

Test_Compound is defined as wells containing test compound.
Low_Control is defined as wells containing Acetylcholine at EC20 and DMSO.
High_Control is defined as wells containing Acetylcholine (EC100) and DMSO.

A mathematical algorithm was used to determine nominally activating compounds in the primary screen. Two values were calculated for each assay plate: (1) the average percent activation of test compound wells and (2) three times their standard deviation. The sum of these two values was used as a cutoff parameter on an individual plate basis, i.e. any compound that exhibited greater % activation than the plate based cutoff parameter was declared active.

PubChem Activity Outcome and Score:

The inactive compounds of this assay have an activity score range of 0 to 78 and the active compounds have an activity score range of 50 to 100.

The reported PubChem Activity Score has been normalized to 100% observed primary activation. Negative % activation values are reported as activity score zero.

List of Reagents:

Cell line: Chinese Hamster Ovary (CHO) cells containing hM1 receptor; (Conn Lab)
Calcium sensitive dye: Fluo-8 No Wash Calcium Assay Kit; (AAT Bioquest, part 36316)
Growth media: Ham's F-12; 10% FBS, 20mM HEPES, 50?g/mL G418
Assay media: Ham's F-12, 10% FBS, 20 mM HEPES
Assay plates: Aurora black/clear 1536well FLIPR plate; (Aurora, part 00019326)
Probenecid: 250mM (pH 8.0); (Sigma P8761)
Potentiator: Acetylcholine (50mM stock in water); Sigma A9187

Comment: Due to the increasing size of the MLPCN compound library, this assay may have been run as two or more separate campaigns, each campaign testing a unique set of compounds. All data reported were normalized on a per-plate basis. Possible artifacts of this assay can include, but are not limited to: dust or lint located in or on wells of the microtiter plate, and compounds that modulate well fluorescence. All test compound concentrations reported above and below are nominal; the specific test concentration(s) for a particular compound may vary based upon the actual sample provided by the MLSMR.

External ID: SIAE_INH_FP_1536_1X%INH PRUN

Protocol: Assay Overview:

The purpose of this biochemical assay is to identify compounds that act as inhibitors of sialic acid acetylesterase (SIAE). In this assay, SIAE protein is incubated with test compounds and fluorophosphonate-rhodamine (FP-Rh) activity-based probe. The reaction is excited with linear polarized light and the intensity of the emitted light is measured as the polarization value (mP). As designed, test compounds that act as SIAE inhibitors will prevent SIAE-probe interactions, thereby increasing the proportion of free (unbound) fluorescent probe in the well, leading to low fluorescence polarization. Compounds are tested in singlicate at a nominal test concentration of 9.66 micromolar.

Protocol Summary:

Prior to the start of the assay, 3 microliters of assay buffer (1X DPBS and 0.01% Pluronic F-127) were dispensed into column 1 thru column 3 of 1536 microtiter plates. Next, 3 microliters of assay buffer containing 0.73uM of SIAE protein were dispensed into columns 4 thru 48. Then, 39 nL of test compound in DMSO or DMSO alone (0.97% final concentration) were added to the appropriate wells and incubated for 45 minutes at 25 degrees Celsius.

The assay was started by dispensing 1.0 microliter of 300 nM FP-Rh in assay buffer to all wells. Plates were centrifuged and after 120 minutes of incubation at 25 degrees Celsius, fluorescence polarization was read on a Viewlux microplate reader (PerkinElmer, Turku, Finland) using a BODIPY TMR FP filter set and a BODIPY dichroic mirror (excitation = 525nm, emission = 598nm) for 25 seconds for each polarization plane (parallel and perpendicular).

Prior to further calculations, the following formula was used to calculate fluorescence polarization (FP):

FP = ( Raw1 - Raw2 ) / ( Raw1 + Raw2 )

Where:

Raw1 is defined as the S channel.
Raw2 is defined as the P channel.

The percent inhibition for each compound was calculated as follows:

100 *( ( Test_Compound - Median_Low_Control ) / ( Median_High_Control - Median_Low_Control ) )

Where:

Test_Compound is defined as wells containing SIAE protein in the presence of test compound and FP-Rh.
High_Control is defined as wells containing DMSO, FP-Rh but, no SIAE protein.
Low_Control is defined as the median of the wells containing test compounds.

PubChem Activity Outcome and Score:

A mathematical algorithm was used to determine nominally inhibiting compounds in the primary screen. Four values were calculated: (1) the average percent inhibition of all high controls tested plus three times the standard deviation of the high controls, (2) the average percent inhibition of all low controls tested minus three times the standard deviation of the low controls, (3) the average percent inhibition of all compounds tested between (1) and (2), and (4) three times their standard deviation. The sum of two of these values, (3) and (4), was used as a cutoff parameter, i.e. any compound that exhibited greater % inhibition/activity than the cutoff parameter was declared active.

The reported PubChem Activity Score has been normalized to 100% observed primary inhibition. Negative % inhibition values are reported as activity score zero.

The activity score range for active compounds is 100-2, for inactive 2-0.

List of Reagents:

SIAE protein (supplied by Assay Provider)
FP-Rh probe (supplied by Assay Provider)
DPBS (Mediatech, part 20-031-CV)
Pluronic F-127 (Invitrogen, part P6866)
1536-well plates (Greiner, part 789176)

Comment: Due to the increasing size of the MLPCN compound library, this assay may have been run as two or more separate campaigns, each campaign testing a unique set of compounds. All data reported were normalized on a per-plate basis. Possible artifacts of this assay can include, but are not limited to: dust or lint located in or on wells of the microtiter plate, compounds that modulate well fluorescence. All test compound concentrations reported above and below are nominal; the specific test concentration(s) for a particular compound may vary based upon the actual sample provided by the MLSMR.

External ID: 2084-01_Activator_SinglePoint_HTS_Activity

Protocol: MITF Primary Screening Protocol
(TRPM-1 Promoter//Luciferase reporter assay)

Day 1, plate cells 2000 per well in 30 uL media (phenol red free DMEM/10% iFBS/Pen/Strep/L-Glutamine)

Day 2, pin 100 nL into 30 uL assay volume in white, opaque Corning 8867 barcoded 384 well plates. (will also require sentinel pinning with the positive control, parthenolide)
Incubate 24 hours at 37 degrees C in Liconic incubator

Day 3, add 20 uL 100% Promega Steady glo with Thermo Combi fluid transfer apparatus.
Shake 15 seconds on "big bear" plate shaker.
Incubate at RT for 5 minutes.
Read on Perkin-Elmer Envision with US LUM settings for 0.5 sec per well

Comment: PRESENCE OF CONTROLS: Neutral control wells (NC) and positive control wells (PC) were included on every plate.

EXPECTED OUTCOME: Active compounds result in increasing readout signal.
NORMALIZATION:
The raw signals of the plate wells were normalized using the 'Neutral Controls Minus Inhibitors' method in Genedata Assay Analyzer (v7.0.3):
The median raw signal of the intraplate neutral control wells was set to a normalized activity value of 0.
The median raw signal of the intraplate positive control wells was set to a normalized activity value of 100.
Experimental wells values were scaled to this range.
PATTERN CORRECTION: The plate pattern correction algorithm 'Runwise Pattern (Multiplicative)' in Genedata (v7.0.3) was applied to the normalized plate data.

PUBCHEM_ACTIVITY_SCORE:
This was set as equal to the mean of the normalized and corrected sample replicate activities, rounded to the nearest integer .
The minimum PUBCHEM_ACTIVITY_SCORE required for a compound to be called a hit (the activity threshold, or AT) was set at 80.

PERCENTAGE OF ACTIVE REPLICATES:
For each sample, the percentage of replicates (PCT_ACTIVE_REP) which had activity scores >= AT was determined.
The minimum percentage of replicates required for a compound to be called a hit (PAR_T) was set at 100.

PUBCHEM_ACTIVITY_OUTCOME:
Samples passing BOTH threshold criteria were assigned an outcome of 2 (active):
PUBCHEM_ACTIVITY_SCORE >= AT, and PCT_ACTIVE_REP >= PAR_T

Samples passing NEITHER threshold criteria were assigned an outcome of 1 (inactive):
PUBCHEM_ACTIVITY_SCORE < AT, and PCT_ACTIVE_REP < PAR_T

Samples passing AT only were assigned an outcome of 3 (inconclusive) :
PUBCHEM_ACTIVITY_SCORE >= AT, and PCT_ACTIVE_REP < PAR_T

Samples passing PAR_T only were assigned an outcome of 3 (inconclusive) :
PUBCHEM_ACTIVITY_SCORE < AT, and PCT_ACTIVE_REP >= PAR_T

External ID: GDH-TPI_INH_ABS_1536_1X%INH CSRUN

Protocol: Assay Overview:

The purpose of this biochemical counterscreen is to determine whether compounds act as absorbance assay artifacts or are non-selective. This assay also serves as a counterscreen for a set of ongoing high throughput primary experiments entitled, "Absorbance-based biochemical primary high throughput screening assay to identify inhibitors of the aldolase of M. tuberculosis."

This counterscreen is similar in format to the aforementioned assay with the only two following differences: (i) the fructose-1,6-bisphosphate substrate is replaced with glyceraldehyde 3 phosphate, a product of its conversion by FBA and (ii) no (FBA) is used. The counterscreen hence recapitulates the two steps involved in the monitoring of FBA activity through the conversion of FB into the triose product glyceraldehyde 3 phosphate (G3P), which would be converted to dihydroxyacetone phosphate (DHAP) by the helper enzyme triose phosphate isomerase (TPI). A second helper enzyme, glycerophosphate dehydrogenase (GDH), converts the dihydroxyacetone phosphate to glycerol-3-phosphate with the concomitant oxidation of NADH to NAD, which is monitored by measuring the absorbance at 340 nm. In this new assay format, the A340 is independent of FBA activity, hence compounds that reduce absorbance at 340 nm are either absorbance artifacts or helper enzyme inhibitors that will not be pursued. Compounds are tested in singlicate at a final nominal concentration of 4.78 uM.

Protocol Summary:

Prior to the start of the assay, 5 uL /well of Buffer A (50 mM HEPES, 0.01% Triton X-100, 10% Glycerol, pH8.0) supplemented with 400 nM ZnCl2,240 uM NADH and the helper enzymes GDH-TPI (4 U/mL) was dispensed into all wells of a 1536-well plate except the "No enzyme" wells that contained the same supplemented buffer but no GDH-TPI enzymes. Next, 48 nL of test compounds were then delivered in each well using a PinTool. The assay was then initiated by dispensing 5 uL of Buffer A supplemented with 240 uM of the substrate glyceraldehyde-3-phosphate (G3P). Plates were incubated at room temperature for 20 minutes before A340 was measured using the EnVision plate reader (Perkin Elmer).

The percent inhibition for each compound was calculated as follows:

%Inhibition = 100 * ( ( Test_Compound - Median_Low_Control ) / ( Median_High_Control - Median_Low_Control ) )

Where:

Test_Compound is defined as wells treated with test compounds.
Low_Control is defined as wells treated with DMSO.
High_Control is defined as wells with no GDH-TPI enzyme.

A mathematical algorithm was used to determine nominally inhibiting compounds in the primary screen. Two values were calculated for each assay plate: (1) the average percent inhibition of test compound wells and (2) three times their standard deviation. The sum of these two values was used as a cutoff parameter for each plate, i.e. any compound that exhibited greater % inhibition than the cutoff parameter was declared active.

PubChem Activity Outcome and Score:

The reported PubChem Activity Score has been normalized to 100% observed inhibition. Negative % inhibition values are reported as activity score zero.

The PubChem Activity Score range for active compounds is 100-13, and for inactive compounds 13-0.

List of Reagents:

ZnCl2 (Fisher Scientific, part Z33-500)
NADH (EMD Biosciences, part 481913)
GDH-TPI (Sigma, part G1881)
HEPES (EMD Biosciences, part EM-5310)
Triton X-100 (Sigma, part T8787)
Glycerol (Fisher, part AC327255000)
Glyceraldehyde-3-phosphate (Sigma, part D7137)
1536-well plates (Aurora, part 1091-11020-S)

Comment: Due to the increasing size of the MLPCN compound library, this assay may have been run as two or more separate campaigns, each campaign testing a unique set of compounds. In this case the results of each separate campaign were assigned "Active/Inactive" status based upon that campaign's specific compound activity cutoff value. All data reported were normalized on a per-plate basis. Possible artifacts of this assay can include, but are not limited to: dust or lint located in or on wells of the microtiter plate, and compounds that quench or emit absorbance within the well. All test compound concentrations reported are nominal; the specific concentration for a particular test compound may vary based upon the actual sample provided by the MLSMR

External ID: HERG01

Protocol: NCGC Assay Protocol Summary:

HERG assay (FluxORTM thallium flux assay) was initially developed by Invitrogen/Molecular Probes, and then miniaturized into 1536-well plate in a homogeneous format by NCGC. This assay measures the activity of potassium channel using thallium dye (FluxOR) flux as surrogate measurement for potassium into the cells with a FDSS-7000 kinetic plate reader (Hamamatsu Corp., Hamamatsu City, Japan). The hERG ion channel is transduced into mammalian cells (U2OS) using a baculovirus (Bacmam) construct harboring the hERG K+ ion channel. So far we screened LOPAC1280 library (Sigma), the NTP collection of 1408 compounds, and the NCGC Pharmaceutical Collection (NPC), in which many well defined HERG blockers are present. The rank order potencies of many of these compounds are similar to that of other HERG assays (membrane potential, Rb+ flux, patch clamp, etc). This quick and homogeneous assay is also found to be sensitive, specific, and robust.

Using the FluxORTM thallium flux assay, the activity of potassium channel using thallium dye (FluxOR) flux as surrogate measurement for potassium into the cells was measured in the U2OS cell line transduced with hERG K+ ion channel using a baculovirus (Bacmam) using Opti-MEM medium (Invitrogen) containing 2% fetal calf serum (FCS, HyCone) following loading buffer addition, compound treatment for around 10 minutes and finally adding stimulation buffer. The assay was performed in black clear Kalypsys 1536-well plates. In the screen, Astemizole was used as positive controls. Library compounds were measured for their ability to cause hERG channel blockage in the cell line, as reflected by a decrease in fluorescence intensity, in a concentration-dependent manner. Data were normalized to the controls for basal activity (DMSO only) and 100% inhibition (5uM Astemizole). AC50 values were determined from concentration-response data modeled with the standard Hill equation.

qHTS protocol for hERG-U2OS cellular assay

[Step] [Parameter] [Value] [Description]

1. Day 1: Replace medium in 70-80% confluent T225 flask with 2.5 mL of hERG-BacMam virus plus 12.5 mL of phosphate buffered saline (PBS) (corresponding roughly to a multiplicity of infection ratio of 100 virus particles/cell)
2. Incubation: 4 hrs @ room Temperature in Dark
3. Reagent; Remove virus; wash once with 25 ml DPBS
4. Reagent; 35 ml culture medium
5. Incubation; 37oC overnight
6. Day2: Reagent; 3 uL; 2000 U2OS cells/well
7. Time; 4 hr; 37oC incubation
8. Loading buffer; 1 uL; 0.7X;
9. Incubation: 1hr @ RT in Dark.
10. Compounds; 23 nL; 0.59 nM to 92 uM
11. Controls; 23 nL; Astemizole 1.4 nM to 92 uM
12. Time; 10min; 37oC incubation
13. Read fluorescence Intensity on FDSS for 10 Sec with 1 sec interval
14. Reagent; 1 uL; stimulation buffer
15. Read fluorescence Intensity on FDSS for 2 min with 1 sec interval
16. Detection; Fluorescence Intensity; FDSS

Comment: Compound Ranking:

1. Compounds are first classified as having full titration curves, partial modulation, partial curve (weaker actives), single point activity (at highest concentration only), or inactive. See data field "Curve Description". For this assay, apparent inhibitors are ranked higher than compounds that showed apparent activation.
2. For all inactive compounds, PUBCHEM_ACTIVITY_SCORE is 0. For all active compounds, a score range was given for each curve class type given above. Active compounds have PUBCHEM_ACTIVITY_SCORE between 40 and 100. Inconclusive compounds have PUBCHEM_ACTIVITY_SCORE between 1 and 39. Fit_LogAC50 was used for determining relative score and was scaled to each curve class' score range.

External ID: CHEMBL4303805

Protocol: N/A

Comment: Target ChEMBL ID: CHEMBL4303835
ChEMBL Target Name: SARS-CoV-2
ChEMBL Target Type: ORGANISM - Target is a complete organism
Relationship Type: N - Non-molecular target assigned
Confidence: Target assigned is non-molecular

Data Source: SARS-CoV-2 Screening Data

External ID: CHEMBL4303819

Protocol: N/A

Comment: Target ChEMBL ID: CHEMBL4303835
ChEMBL Target Name: SARS-CoV-2
ChEMBL Target Type: ORGANISM - Target is a complete organism
Relationship Type: N - Non-molecular target assigned
Confidence: Target assigned is non-molecular

Data Source: SARS-CoV-2 Screening Data

External ID: SMAD3201

Protocol: Suspensions of trypsinized HEPG2 CAGA-GFP cells were dispensed into white, tissue culture-treated, solid 1536-well plates at 5uL/well (1000 cells/well final concentration) in DMEM medium supplemented with 1% FBS. Plates were incubated at 37 degrees C for 2 hours, after which 23 nL of compounds or DMSO were delivered to each well using a pin tool. One uL of recombinant TGF-beta in DMEM (1% FBS) was then dispensed (500 pg/mL final concentration), and plates were incubated at 37 degrees C for 18 hours. Two uL of CellTiter Glo (Promega), a luminescence-based viability reagent, was dispensed, followed by a 10 minute room temperature incubation. The plates were then measured on a PerkinElmer ViewLux plate reader for luminescence (clear filter) using a 5 second exposure. The %Activity was determined from the corrected luminescence values. Wells containing media only (no cells) were used to normalize %Activity of identified toxic compounds; media-only wells corresponded to 100%Activity (complete cell-killing), while DMSO-dosed cell controls were used to normalize 0%Activity (no toxicity).

Concentration-response curves were fitted to the signals arising from the resulting luminescence. The concentration-effect curves were then classified based on curve quality (r2), response magnitude and degree of measured activity, and compounds were subsequently categorized based on their curve class. Toxic compounds showed concentration-dependent decreases in luminescence, concordant with a decrease in intracellular ATP concentration (CellTiter Glo's marker of viability), and thus a decrease in the number of viable cells. Inactive (non-toxic) compounds showed no effect on luminescence signal. Active (toxic) compounds showed concentration dependent decrease in luminescence.

Comment: Compound Ranking:

1. Compounds are first classified as having full titration curves, partial modulation, partial curve (weaker actives), single point activity (at highest concentration only), or inactive. See data field "Curve Description".

2. For all inactive (non-toxic) compounds, PUBCHEM_ACTIVITY_SCORE is 0. For all active (toxic) compounds, a score range was given for each curve class type given above. Active (toxic) compounds have PUBCHEM_ACTIVITY_SCORE between 40 and 100. Inconclusive compounds have PUBCHEM_ACTIVITY_SCORE between 1 and 39. Fit_LogAC50 was used for determining relative score and was scaled to each curve class' score range.

External ID: SBCCG-A764-CF-PAF-Primary-Assay

Protocol: Assay Materials:
KKLEB-NFkB-GFP cells (Assay Provider)
PAF(Assay Provider)
Fetal Bovine Serum (Hyclone SH30396.03)
Penicillin Streptomycin solution
L-glutamine (100X)
TrypLE (Invitrogen 12563)
DPBS without calcium and magnesium (1X)
Corning culture flasks
Black CellBind 1536-well plates (Corning 3833)
ATPlite (Perkin Elmer 6016739)

I. Cell Suspension
1- Dispense 3 uL/well of cells at 5X10;5 cells/mL to the whole plate (plate cells in 2% FBS assay media).
2- Spin down plates on Eppendorf centrifuge 5810 at 500 rpm for 1 minute.

II. Compound Addition:
3- Transfer test compounds to columns 5-48 and DMSO to columns 1-4 using the Labcyte ECHO 555.
4- Transfer volume of test compound and DMSO is 15nL, making 5uM compound concentration at 0.25% DMSO final.
5-Spin down plates on Vspin at 1000 rpm for 1 minute.
6-Put Kalypsys metal lids on plates, incubate plates at 37 degrees C with 5% CO2 for 2 hours.

III. Reagent Addition
7- Dispense 3 uL/well of serum free assay media to columns 1 and 2.
8- Dispense 3 uL/well of PAF (dilute in serum free assay media) to columns 3-48.
9- Spin down plates without lids on Vspin at 2000 rpm for 2 min
10- Put Kalypsys metal lids on plates, and incubate plates at 37 degrees C with 5% CO2 overnight.

IV. Reading plates:

11-Spin plates upside down with a container at 1000 rpm for 15 sec. Dab them with a tissue to dry them and Read immediately on envision for GFP fluorescence.
12-Dispense 6 uL/well of ATPlite (diluted in DPBS 1:1).
13-Spin down plates on Eppendorf centrifuge 5810 at 2000 rpm for 2 minutes without lids.
14-Incubate plates for 10 min at RT and run Luminescence read on Viewlux.

Comment: Compounds that demonstrated a corrected %Activity of >= 50% at 5 uM concentration are defined as actives in this assay.

The experimental values were normalized by the difference between values from neutral and stimulator control wells in each plate. Then normalized data was corrected to remove systematic plate patterns due to artifacts such as dispensing tip issues etc. Further information about data correction is available at http://www.genedata.com/products/screener.html.

To simplify the distinction between the inactives of the primary screen and of the confirmatory screening stage, the Tiered Activity Scoring System was developed and implemented. Its utilization for the assay is described below.

Activity Scoring
Activity scoring rules were devised to take into consideration compound efficacy, its potential interference with the assay and the screening stage that the data was obtained. Details of the Scoring System will be published elsewhere. Briefly, the outline of the scoring system utilized for the assay is as follows:
1) First tier (0-40 range) is reserved for primary and single-concentration confirmation screening data.
a. If outcome of the primary screen is inactive, then the assigned score is 0
b. If outcome of the primary screen is inconclusive, then the assigned score is 10
c. If outcome of the primary screen is active, then the assigned score is 20
d. If outcome of the single-concentration confirmation screen is inactive, then the assigned score is 21
e. If outcome of the single-concentration confirmation screen is inconclusive, then the assigned score is 25
f. If outcome of the single-concentration confirmation screen is active, then the assigned score is 30.
This scoring system helps track the stage of the testing of a particular SID. For the primary hits which are available for confirmation, their scores will be greater than 20. For those which are not further confirmed, their score will stay under 21.

2) Second tier (41-80 range) is reserved for dose-response confirmation data and is not applicable in this assay

3) Third tier (81-100 range) is reserved for resynthesized true positives and their analogues and is not applicable in this assay

External ID: CHRM1_ANT_FLUO8_1536_1X%INH PRUN

Protocol: Assay Overview:

The purpose of this assay is to identify compounds that act as antagonists and decrease activity of the human M1 muscarinic receptor (CHRM1; M1) that have been pre-treated with a known agonist, with the end result being a decrease in intracellular calcium. In this assay, CHO-K1 cells stably expressing human M1 are loaded with the Fluo-8 calcium indicator dye. Compounds are added followed by treatment with the activator acetylcholine at a concentration that results in 80% activation (Ec80). As designed, compounds that act as CHRM1 antagonists will decrease calcium mobilization, resulting in decreased relative fluorescence of the indicator dye below that of the Ec80 of acetylcholine. Compounds are tested in singlicate at a final nominal concentration of 3 uM.

Protocol Summary:

The CHO-hM1 cell line was routinely cultured in T-175 sq cm flasks at 37 C and 95% relative humidity (RH). The growth media consisted of Ham's F-12 Nutrient Media (F-12) supplemented with 10% v/v heat-inactivated qualified fetal bovine serum, 20 mM HEPES, 50 ug/mL Geneticin, and 1X antibiotic mix (penicillin and streptomycin).

The day before the assay 3000 cells in 3 uL of growth media were seeded into each well of 1536 well microtiter plates and allowed to incubate at 37 C, 5% CO2, and 95 % RH for 17-24 hours. Next, 2 uL of the fluorogenic Fluo-8 intracellular calcium indicator mixture (prepared according to the manufacturer's protocol) was added to each well. Plates were then incubated for 1 hour at 37 C, 5% CO2, and 95 % RH, followed by 30 minute incubation at room temperature. Then, 15 nL of test compound in DMSO were transferred to appropriate wells. The assay was started by performing a basal read of plate fluorescence (470 - 495 nm excitation and 515 - 575 nm emission) for 5 seconds on the FLIPR Tetra (Molecular Devices) prior to all wells being treated with an EC80 concentration of acetylcholine. Then a real time fluorescence measurement was immediately performed for the remaining 140 seconds of the assay.

Hits for this assay were determined according to the following mathematical expression:

Ratio = I_Max / I_Min

Where:

I_Max represents the maximum measured fluorescence emission intensity over the 140 second read and,
I_Min represents the minimum (basal) measured fluorescence emission intensity before compound was added.

The percent inhibition was calculated from the median ratio as follows:

%_Inhibition = ( 1 - ( Ratio Test_Compound - Median_Ratio_High_Control ) / ( Median_Ratio_Low_Control - Median_Ratio_High_Control ) ) ) * 100

Where:

Test_Compound is defined as wells containing test compound.
Low_Control is defined as wells containing Ec80 of acetylcholine and DMSO.
High_Control is defined as wells containing DMSO.

PubChem Activity Outcome and Score:

A mathematical algorithm was used to determine nominally inhibiting compounds in the primary screen. Two values were calculated for each assay plate: (1) the average percent inhibition of test compound wells and (2) three times their standard deviation. The sum of these two values was used as a cutoff parameter for each plate, i.e. any compound that exhibited greater % inhibition than that particular plate's cutoff parameter was declared active.

The reported PubChem Activity Score has been normalized to 100% observed inhibition. Negative % inhibition values are reported as activity score zero.

The PubChem Activity Score range for active compounds is 100-7, and for inactive compounds 80-0.

In this assay not all plates were run in the same batch. This resulted in batch-to-batch variation among the different batches of plates, thereby necessitating the use of a plate-based activity cutoff. For this reason the inactive and active scores overlap.

List of Reagents:

Cell line: Chinese Hamster Ovary (CHO) cells containing hM1 receptor; (Conn Lab)
Calcium sensitive dye: Fluo-8 No Wash Calcium Assay Kit; (AAT Bioquest, part 36316)
Growth media: Ham's F-12; 10% FBS, 20mM HEPES, 50 ug/mL G418
Assay media: Ham's F-12, 10% FBS, 20 mM HEPES
Assay plates: Aurora black/clear 1536well FLIPR plate; (Aurora, part 00019326)
Probenecid: 250mM (pH 8.0); (Sigma P8761)
Potentiator: Acetylcholine (50 mM stock in water); Sigma A9187

Comment: Due to the increasing size of the MLPCN compound library, this assay may have been run as two or more separate campaigns, each campaign testing a unique set of compounds. All data reported were normalized on a per-plate basis. Possible artifacts of this assay can include, but are not limited to: dust or lint located in or on wells of the microtiter plate, and compounds that modulate well fluorescence. All test compound concentrations reported above and below are nominal; the specific test concentration(s) for a particular compound may vary based upon the actual sample provided by the MLSMR.

External ID: HSPH_Screening_CFS_001

Protocol: Preparation of assay plates and seeding cells:
Polyacrylamide based gel substrates were miniaturized in glass bottom 96-well plates. In the first method, each 96-well plate was treated with NaOH (6N in water) for 1hr followed by silane solution ((3-aminopropyl)trimethoxysilane, 10% in water) for an additional 1hr. Then, glass surfaces were treated with glutaraldehyde (0.25% in PBS) for 30min and further washed and dried. Acrylamide gels (5.5% acrylamide, 0.076% bisacrylamide, Young's modulus = 1.8kPa, thickness = 200 microm) were cast in each well using a custom-made gel caster. The gel surfaces were functionalized using sulfo-SANPAH (sulfosuccinimidyl-6-[4 -azido-2 -nitrophenylamino]hexanoate, 0.2mg/mL), coated with green beads (0.2microm sulfate microspheres, Invitrogen, 0.002% in water), coated with bovine collagen I (40microg/mL in PBS) and were stored at 4C (Fig. 1A) for more than 1 day. After washing off collagen solution, primary human airway smooth muscle cells were seeded in each well (10,000 cells/well). 1 day after seeding, media was replaced with serum-deprivation media and cells were kept in serum free media for 2 days.

Measurements of contractile forces using Fourier-transform traction microscopy:
On the day of screening, 96-well plate was mounted upon a motorized stage within a temperature controlled chamber and imaged using an inverted microscope (DMI 6000B, Leica Inc.). In each well, images were obtained in quick succession: one phase contrast image of cells and a fluorescent images of beads. The image set was obtained before plating cells (reference), immediately prior to adding drugs (baseline), and 1 hr after drug addition (treatment). By comparing fluorescent images obtained during baseline or treatment with the corresponding image from reference, we computed the cell-exerted displacement field using particle image velocimetry. From the displacement field, we computed the contractile force (per unit area) using Fourier-transform traction microscopy modified to the case of cell monolayers. This modified approach takes into consideration effects of finite gel thickness as well as force imbalances associated with the microscope field of view as we described previously. From each force map, we computed the root mean squared value to represent the averaged contractile force. Drug effects were quantified as the 'force response ratio' (FRR), namely, the contractile force before versus after drug addition.

Small molecule library and pooling:
Prestwick 1 library was screened with pooling 4 compounds together.

Comment: Primary measurements of the screening are FRR (force response ratio). 1 means no change in average contractile force and less than 1 means the reduction of average contractile force after drug treatment.
Among the mixtures having FRR less than 1, 11 most effective mixtures were chosen as positives.

External ID: FLUC100

Protocol: NCGC Assay Protocol Summary:

Reagents: 50mM Tris acetate, pH 7.5; 10mM Mg acetate; 10uM D-luciferin (Sigma #L9504); 10uM ATP; 0.01% Tween-20; 0.05% BSA; 10nM P. pyralis luciferase (Sigma #L9506)
Control compounds used were two known firefly luciferase inhibitors (compounds (2) and (5) in Auld et al., 2010), and DMSO.

Assay Summary:
Three microliters containing firefly luciferase substrates in buffer (final concentrations: 50mM Tris acetate, pH 7.5, 10mM Mg acetate, 0.01% Tween-20, 0.05% BSA, 10uM D-luciferin, and 10uM ATP) are dispensed into each well of a Greiner white, solid-bottom 1536-well format plate using a flying reagent dispenser (FRD). These assay plates were then treated with 23nL of compound or DMSO using a Kalypsys pin tool, which allows for delivery of a 6-point interplate titration of each compound to the assay plate (quantitative HTS), with a final compound concentrations ranging from approximately 60muM to 7pM. One microliter of firefly luciferase in 500mM Tris-acetate buffer was then delivered by FRD to each well for a final enzyme concentration of 10nM. Luciferase activity was then measured using a ViewLux CCD imager (PerkinElmer), with an average exposure time of 2-30 seconds (2X binning, medium/high gain).

Keywords: NIH Roadmap, MLPCN, MLSMR, qHTS, miR-21, firefly luciferase, FLuc, miRNA.

Comment: Compound Ranking:

1. Compounds are first classified as having full titration curves, partial modulation, partial curve (weaker actives), single point activity (at highest concentration only), or inactive. See data field "Curve Description". For this assay, apparent inhibitors are ranked higher than compounds that showed apparent activation.
2. For all inactive compounds, PUBCHEM_ACTIVITY_SCORE is 0. For all active compounds, a score range was given for each curve class type given above. Active compounds have PUBCHEM_ACTIVITY_SCORE between 40 and 100. Inconclusive compounds have PUBCHEM_ACTIVITY_SCORE between 1 and 39. Fit_LogAC50 was used for determining relative score and was scaled to each curve class' score range.

External ID: SMAD3101

Protocol: Suspensions of trypsinized HEPG2 CAGA-GFP cells were dispensed into white, tissue culture-treated, solid 1536-well plates at 5uL/well (1000 cells/well final concentration) in DMEM medium supplemented with 1% FBS. Plates were incubated at 37 degrees C for 2 hours, after which 23 nL of compounds or DMSO were delivered to each well using a pin tool. One uL of recombinant TGF-beta in DMEM (1% FBS) was then dispensed (500 pg/mL final concentration), and plates were incubated at 37 degrees C for 18 hours. The plates were measured on an Acumen eX3 Explorer plate reader for GFP fluorescence (ex488/em500-530). GFP values were calculated by determining the mean GFP fluorescence of individual cells, and compiling these values for each well to determine a total well GFP signal. The %Activity was determined from the corrected fluorescence values. A titration of the known TGF-B inhibitor SB431542 was included to monitor plate performance, while unstimulated HEPG2 (-TGF-B) control wells were used to normalize %Activity of identified inhibitors; unstimulated wells corresponded to 100%Activity (full inhibition), while stimulated cell controls (+DMSO) were used to normalize 0%Activity (no inhibition).

Concentration-response curves were fitted to the signals arising from the resulting fluorescence. The concentration-effect curves were then classified based on curve quality (r2), response magnitude and degree of measured activity, and compounds were subsequently categorized based on their curve class. Active inhibitors showed concentration-dependent decreases in GFP fluorescence, concordant with a decrease in TGF-B/SMAD3-driven GFP expression. Inactive compounds showed no effect on fluorescence signal.

Comment: Compound Ranking:

1. Compounds are first classified as having full titration curves, partial modulation, partial curve (weaker actives), single point activity (at highest concentration only), or inactive. See data field "Curve Description". For this assay, apparent inhibitors are ranked higher than compounds that showed apparent activation.
2. For all inactive compounds, PUBCHEM_ACTIVITY_SCORE is 0. For all active compounds, a score range was given for each curve class type given above. Active compounds have PUBCHEM_ACTIVITY_SCORE between 40 and 100. Inconclusive compounds have PUBCHEM_ACTIVITY_SCORE between 1 and 39. Fit_LogAC50 was used for determining relative score and was scaled to each curve class' score range.

External ID: SRC3_INH_LUMI_1536_1X%INH PRUN

Protocol: Assay Overview:

The purpose of this assay is to identify compounds that act as inhibitors of the steroid receptor coactivator 1 (SRC3), also known as nuclear receptor coactivator 3 (NCOA3). In this assay, HEK293 cells are transfected with a GAL4-responsive reporter plasmid (pGL4.31, Promega) and an expression vector encoding SRC-3 fused to the DNA-binding domain of GAL4(pBIND-SRC-3). The ability of compounds to reduce coactivator transcriptional activity is assessed by measuring luciferase expression from the reporter gene plasmid. As designed, compounds that inhibit SRC3 ability to induce transcription will lead to a decrease in expression of the luciferase gene, resulting in reduced well luminescence. Compounds are tested in singlicate at a final nominal concentration of 3.6 uM.

Protocol Summary:

Seven million HEK293 cells were seeded into T-175 flasks containing 23 mLs of DMEM media supplemented with 10% v/v fetal bovine serum and 1% v/v Anti-Anti. Flasks were then incubated for 48 hours at 37 C, 5% CO2 and 95% relative humidity (RH). The day prior to the assay, cells were harvested using TrypLE, resuspended in fresh media at a density of 1 million cells per mL and seeded into new T-175 flasks (23 mL per flask). After allowed to attach for one hour at 37 C, 5% CO2 and 95% RH, cells were transfected with 1 mL of preincubated mix of serum-free OptiMEM containing 23 ug of the pGL4.31 reporter plasmid, 2.3 ug of pBIND-SRC3 vector, and 80 uL of transfection reagents. Twenty four hours post transfection, cells were harvested using 5 mL of TrypLE and resuspended at a concentration of 750,000 cells per mL in phenol-red free DMEM media supplemented as described above.

The assay was started by dispensing 5 uL of cell suspension into each well of a white, solid-bottom 1536-well plate using a flying reagent dispenser (3,750 cells per well). The first two columns received cells transfected with reporter plasmid and an empty pBIND vector as a control for background luminescence. Cells were then treated with 18 nL/well of test compounds, DMSO as a negative control (final concentration 0.36%), or Gossypol as a positive control (36 uM final) using a PinTool transfer unit (GNF). Plates were then placed in the incubator at 37 C, 5% CO2 and 95% RH. Twenty four hours later, plates were removed from the incubator and equilibrated to room temperature for 10 minutes. Luciferase activity was detected by adding 5 uL per well of ONE-Glo luciferase detection reagent. After a 15 minute incubation time, light emission was measured using the ViewLux plate reader (PerkinElmer).

The percent inhibition of each test compound was calculated as follows:

%_Inhibition = ( 1 - ( median_positive_control - test_compound ) / ( median_positive_control - median_negative_control ) * 100

Where:

Test_Compound is defined as wells containing test compound treated cells.
Positive_Control is defined as wells containing Gossypol treated cells.
Negative_Control is defined as wells containing DMSO treated cells.

PubChem Activity Outcome and Score:

A mathematical algorithm was used to determine nominally active compounds. Two values were calculated: (1) the average percent inhibition of all compounds tested, and (2) three times their standard deviation. The sum of these two values was used as a cutoff parameter, i.e. any compound that exhibited greater %inhibition than the cutoff parameter was declared active.

The reported PubChem Activity Score has been normalized to 100% observed primary inhibition. Negative % inhibition values are reported as activity score zero.

The PubChem Activity Score range for active compounds is 100-64, and for inactive compounds 64-0.

List of Reagents:

HEK-293 cells (ATCC, part CRL-1573)
DMEM media (Invitrogen, part 11965)
Fetal Bovine Serum (Hyclone, part SH30088.03)
Anti-Anti (Gibco, part 15240)
TrypLE (Invitrogen, part 12604)
T-175 flasks (Falcon, part 353112)
pGL4.31 (Promega, part C935A)
pBIND-SRC3 (Assay Provider)
TransIT 293 transfection reagent (Mirus Corporation, part MIR-2700)
ONE-Glo luciferase reagent (Promega, part E6130)
White, solid-bottom 1536-well plates (Greiner, part 789173)

Comment: Due to the increasing size of the MLPCN compound library, this assay may have been run as two or more separate campaigns, each campaign testing a unique set of compounds. In this case the results of each separate campaign were assigned "Active/Inactive" status based upon that campaign's specific compound activity cutoff value. All data reported were normalized on a per-plate basis. Possible artifacts of this assay can include, but are not limited to: dust or lint located in or on wells of the microtiter plate, cytotoxic compounds, compounds that perturb the UAS/GAL4 reporter system, and compounds that quench, inhibit, stabilize, or emit luminescence within the well. All test compound concentrations reported are nominal; the specific concentration for a particular test compound may vary based upon the actual sample provided by the MLSMR.

External ID: SRC1_INH_LUMI_1536_1X%INH PRUN

Protocol: Assay Overview:

The purpose of this assay is to identify compounds that act as inhibitors of the steroid receptor coactivator 1 (SRC1), also known as nuclear receptor coactivator 3 (NCOA1). In this assay, HEK293 cells are transfected with a GAL4-responsive reporter plasmid (pGL4.31, Promega) and an expression vector encoding SRC1 fused to the DNA-binding domain of GAL4 (pBIND-SRC-1). The ability of compounds to reduce coactivator transcriptional activity is assessed by measuring luciferase expression from the reporter gene plasmid. As designed, compounds that inhibit SRC1 ability to induce transcription will lead to a decrease in expression of the luciferase gene, resulting in reduced well luminescence. Compounds are tested in singlicate at a final nominal concentration of 3.6 uM.

Protocol Summary:

Seven million HEK293 cells were seeded in T-175 flasks 23 mL of DMEM media supplemented with 10% v/v fetal bovine serum and 1% v/v Anti-Anti. Flasks were then incubated for 48 hours at 37 C, 5% CO2 and 95% relative humidity (RH). The day prior to run the assay, cells were harvested using TrypLE, resuspended in fresh media at a density of 1 million cells per mL and seeded into new T-175 flasks (23 mL per flask). After being allowed to attach for one hour at 37 C, 5% CO2 and 95% RH, cells were transfected with 1 mL of preincubated mix of serum-free OptiMEM containing 23 ug of pGL4.31 reporter plasmid, 2.3 ug of pBIND-SRC1 vector and 80 uL of transfection reagents. Twenty four hours post transfection, cells were harvested using 5 mL of TrypLE and resuspended at a concentration of 750,000 cells per mL in phenol-red free DMEM media supplemented as described above.

The assay was started by dispensing 5 uL of cell suspension into each well of a white, solid-bottom 1536-well plate using a flying reagent dispenser (i.e. 3,750 cells per well). The first two columns received cells transfected with the reporter plasmid and an empty pBIND vector as a control for background luminescence. Cells were then treated with 18 nL/well of test compounds, DMSO as a negative control (final concentration 0.36%) or Gossypol as a positive control (36 uM final) using a PinTool transfer unit (GNF). Plates were then placed in the incubator at 37 C, 5% CO2 and 95% RH. Twenty four hours later, plates were removed from the incubator and equilibrated to room temperature for 10 minutes. Luciferase was detected by adding 5 uL per well of ONE-Glo luciferase detection reagent. After a 15 minutes incubation time, light emission was measured with the ViewLux reader (PerkinElmer).

The percent inhibition of each test compound was calculated as follow:

%_Inhibition = ( 1 - ( median_positive_control - test_compound ) / ( median_positive_control - median_negative_control ) * 100

Where:

Test_Compound is defined as wells containing test compound treated cells.
Positive_Control is defined as wells containing Gossypol treated cells.
Negative_Control is defined as wells containing DMSO treated cells.

PubChem Activity Outcome and Score:

A mathematical algorithm was used to determine nominally active compounds. Two values were calculated: (1) the average percent inhibition of all compounds tested, and (2) three times their standard deviation. The sum of these two values was used as a cutoff parameter, i.e. any compound that exhibited greater % inhibition than the cutoff parameter was declared active.

The reported PubChem Activity Score has been normalized to 100% observed primary inhibition. Negative % inhibition values are reported as activity score zero.

The PubChem Activity Score range for active compounds is 100-63, and for inactive compounds 63-0.

List of Reagents:

HEK-293 cells (ATCC, part CRL-1573)
DMEM media (Invitrogen, part 11965)
Fetal Bovine Serum (Hyclone, part SH30088.03)
Anti-Anti (Gibco, part 15240)
TrypLE (Invitrogen, part 12604)
T-175 flasks (Falcon, part 353112)
pGL4.31 (Promega, part C935A)
pBIND-SRC1 (Assay Provider)
TransIT 293 transfection reagent (Mirus Corporation, part MIR-2700)
ONE-Glo luciferase reagent (Promega, part E6130)
White, solid-bottom 1536-well plates (Greiner, part 789173)

Comment: Due to the increasing size of the MLPCN compound library, this assay may have been run as two or more separate campaigns, each campaign testing a unique set of compounds. In this case the results of each separate campaign were assigned "Active/Inactive" status based upon that campaign's specific compound activity cutoff value. All data reported were normalized on a per-plate basis. Possible artifacts of this assay can include, but are not limited to: dust or lint located in or on wells of the microtiter plate, cytotoxic compounds, compounds that perturb the UAS/GAL4 reporter system, and compounds that quench, inhibit, stabilize, or emit luminescence within the well. All test compound concentrations reported are nominal; the specific concentration for a particular test compound may vary based upon the actual sample provided by the MLSMR.

External ID: CHEMBL4495582

Protocol: N/A

Comment: Target ChEMBL ID: CHEMBL4523582
ChEMBL Target Name: Replicase polyprotein 1ab
ChEMBL Target Type: SINGLE PROTEIN - Target is a single protein chain
Relationship Type: D - Direct protein target assigned
Confidence: Direct single protein target assigned

Data Source: SARS-CoV-2 Screening Data

External ID: APP-Toga-CHIKV-nsp2-p

Protocol: PROTOCOL TABLE (as described by Inglese J, Shamu CE and Guy RK. 2007)
SEQUENCE No. (e.g., 1, 2, 3, etc.); PARAMETER (e.g., Cells, Incubation, Reagent, etc.); VALUE; DESCRIPTION.
1; Control / Compound; 20 nL; Echo 655 acoustic dispenser, Greiner 1536-well solid bottom black plate.
2; Enzyme; 4 uL; BioRAPTR FRD liquid dispenser (Beckman Coulter).
3; Incubation; 15 min; room temperature.
4; Reagent; 4 uL; 2.5 uM Peptide 2 substrate.
5; Incubation; 1 hr; room temperature.
6; Detection; Fluorescence; WiewLux microplate reader (PerkinElmer), 525 nm excitation, 598/25 nm emission.

NOTES (numbers refer to sequence numbers above).
1. Briefly, 20 nL DMSO, positive control ZnAc (20nM final concentration), and test compounds were transferred into a 1,536-well solid bottom black plate (789176-F, Greiner One) via Echo 655 acoustic dispenser (Beckman Coulter). For primary screens, compounds were tested at 7 concentrations, 1:3 dilution points ranging from 25 uM to 34 nM. Follow-up confirmatory screens were carried out at 11 concentrations, 1:3 dilution points from 25 uM to 0.42 nM.
2. Four uL nsP2pro enzyme mix (150 nM final concentration) in 10 mM Tris-HCl pH 8.0 with 0.01% Tween 20 assay buffer was dispensed into the plate using a BioRAPTR FRD liquid dispenser (Beckman Coulter).
3. The plate was incubated at room temperature (protected from light) for 15 min
4. Four microliter of peptide 2 substrate (2.5 uM final concentration) in assay buffer was added to the plate.
5. After 1 hour, plates were immediately read on a ViewLux high-throughput CCD imager (Exposure = 10 sec, Gain = High, Speed = Slow, Binning = 2X). The above assay was also incorporated in the NCATS HTS facility41, which allowed for robotic liquid and compound dispensing, microplate handling, and fluorescence reading..

REFERENCE:
Inglese J, Shamu CE and Guy RK, Reporting data from high throughput screening of small molecule libraries, Nature Chemical Biology, 2007, 3(8): 438-441. doi.org/10.1038/nchembio0807-438.

Comment: Disclaimer:
Although all reasonable efforts have been made to ensure the accuracy and reliability of the data, caution should be exercised when interpreting the results as artifacts are possible from nonspecific effects such as assay signal interference. The curve fitting and activity calls presented here are based on the NCATS analysis methods [1].

Compound Ranking:
1. Compounds are first classified as having full titration curves, partial modulation, partial curve (weaker actives), single point activity (at highest concentration only), or inactive. For this assay, apparent inhibitors are ranked higher than compounds that showed apparent activation.
2. For all inactive compounds, with a ratio activity curve class of 4, PUBCHEM_ACTIVITY_SCORE is 0. For all active compounds, a score range was given for each curve class type given above. Active compounds have PUBCHEM_ACTIVITY_SCORE between 40 and 100. For a ratio activity curve class = -1.1, score = 80+abs((log_ac50+4.5)*inf_activity/20). For ratio.curve_class == -1.2 && abs(ratio.max_response) > 6*10, score = 60+abs((log_ac50+4.5)*inf_activity/20). For ratio.curve_class == -2.1 || ( ratio.curve_class==-2.2 && abs(ratio.max_response) > 6*10), score = 40+abs((log_ac50+4.5)*inf_activity/20). For ratio.curve_class == -1.2 || ratio.curve_class == -2.2, score = 20+abs((log_ac50+4.5)*inf_activity/20). Inconclusive compounds, with a donor curve class other than 4, have PUBCHEM_ACTIVITY_SCORE of 10. Inconclusive compounds have PUBCHEM_ACTIVITY_SCORE between 1 and 39.

Reference:
1. Inglese J, Auld DS, Jadhav A, et al. Quantitative high-throughput screening: a titration-based approach that efficiently identifies biological activities in large chemical libraries. Proc Natl Acad Sci U S A. 2006;103(31):11473-11478.

External ID: CHEMBL4029349

Protocol: N/A

Comment: Journal: Drug Discov Today
Year: 2016
Volume: 21
Issue: 4
First Page: 648
Last Page: 653
DOI: 10.1016/j.drudis.2016.02.015

Target ChEMBL ID: CHEMBL372
ChEMBL Target Name: Homo sapiens
ChEMBL Target Type: ORGANISM - Target is a complete organism
Relationship Type: N - Non-molecular target assigned
Confidence: Target assigned is non-molecular

External ID: CHEMBL4029350

Protocol: N/A

Comment: Journal: Drug Discov Today
Year: 2016
Volume: 21
Issue: 4
First Page: 648
Last Page: 653
DOI: 10.1016/j.drudis.2016.02.015

Target ChEMBL ID: CHEMBL372
ChEMBL Target Name: Homo sapiens
ChEMBL Target Type: ORGANISM - Target is a complete organism
Relationship Type: N - Non-molecular target assigned
Confidence: Target assigned is non-molecular

External ID: Ebola screen1_EMI141217blue

Protocol: This 1536-well plate assay was adapted from the original 6-wells assay with a modification that eliminated cell wash steps. HeLa cells were plated at 750 cells/well in 3 microl of assay medium (DMEM + 10% FBS) in 1536-well assay plates and incubated for 16 hours at 37 degrees C and 5% CO2. Compounds in the 1536-well drug source plates were added to the 1536-well assay plates in a volume of 23 nl/well via a NX-TR pintool station (WAKO Scientific Solutions, San Diego, CA). Following 1-hour incubation at 37 degrees C with 5% CO2, 1 microl/well of VLP solution was added to the assay plates using a BioRapTR FRD dispenser (the VLP solution was diluted in Opti-MEM to a final concentration of 1:16). Plates were then spinoculated by centrifugation at 1500 rpm at 4 degrees C for 45 minutes followed by incubation at 37 degrees C with 5% CO2 for 4.5 hours. The CCF2-AM beta-lactamase substrate was prepared at 6x concentration following the manufacturer's instruction which was added to assay plates at 1 microl/well. Following a 2-hour incubation at room temperature, dual fluorescence intensities (Ex1 = 405+/-20, Em1 = 460+/-20, and Ex2 = 405+/-20, Em2 = 530+/-20 nm) were measured in an EnVision plate reader (PerkinElmer, Boston, MA). The ratio of fluorescence intensities (Em1/Em2) was calculated to represent the beta-lactamase activity that is proportional to the amount of VLP entry into the host cells.

Comment: The activity score was determined using both AC50, Efficacy and curve class. For a given compound j:
Activity is defined as the ability to inhibit viral entry.

If curve class = 4, activity score = 0 and outcome is set to 1. Compounds of this class have no significant activity points.
If efficacy is negative, activity score = 0 and outcome is set to 1. Compounds with negative efficacies, promote viral entry.

For all other curve classes:

Activity score(j) = [100*((max(Ac50)-Ac50(j))/(max(Ac50)-min(Ac50))) + 100*(1-(max(efficacy)-efficacy(j))/(max(efficacy)-min(efficacy))) ]/2

Compounds with Activity scores > 80% are deemed active, and the activity outcome is set to 2.

Refer to the following recent publication for more detail regarding active compounds:

Identification of 53 compounds that block Ebola virus-like particle entry via a repurposing screen of approved drugs

Jennifer Kouznetsova, Wei Sun, Carles Marti nez-Romero, Gregory Tawa, Paul Shinn, Catherine Z Chen,
Aaron Schimmer, Philip Sanderson, John C McKew, Wei Zheng and Adolfo Garci a-Sastre

Emerging Microbes and Infections (2014) 3, e84; doi:10.1038/emi.2014.88

External ID: Ebola screen1_EMI141217_ratio

Protocol: This 1536-well plate assay was adapted from the original 6-wells assay with a modification that eliminated cell wash steps. HeLa cells were plated at 750 cells/well in 3 microl of assay medium (DMEM + 10% FBS) in 1536-well assay plates and incubated for 16 hours at 37 degrees C and 5% CO2. Compounds in the 1536-well drug source plates were added to the 1536-well assay plates in a volume of 23 nl/well via a NX-TR pintool station (WAKO Scientific Solutions, San Diego, CA). Following 1-hour incubation at 37 degrees C with 5% CO2, 1 microl/well of VLP solution was added to the assay plates using a BioRapTR FRD dispenser (the VLP solution was diluted in Opti-MEM to a final concentration of 1:16). Plates were then spinoculated by centrifugation at 1500 rpm at 4 degrees C for 45 minutes followed by incubation at 37 degrees C with 5% CO2 for 4.5 hours. The CCF2-AM beta-lactamase substrate was prepared at 6x concentration following the manufacturer's instruction which was added to assay plates at 1 microl/well. Following a 2-hour incubation at room temperature, dual fluorescence intensities (Ex1 = 405+/-20, Em1 = 460+/-20, and Ex2 = 405+/-20, Em2 = 530+/-20 nm) were measured in an EnVision plate reader (PerkinElmer, Boston, MA). The ratio of fluorescence intensities (Em1/Em2) was calculated to represent the beta-lactamase activity that is proportional to the amount of VLP entry into the host cells.

Comment: The activity score was determined using both AC50, Efficacy and curve class. For a given compound j:
Activity is defined as the ability to inhibit viral entry.

If curve class = 4, activity score = 0 and outcome is set to 1. Compounds of this class have no significant activity points.
If efficacy is negative, activity score = 0 and outcome is set to 1. Compounds with negative efficacies, promote viral entry.

For all other curve classes:

Activity score(j) = [100*((max(Ac50)-Ac50(j))/(max(Ac50)-min(Ac50))) + 100*(1-(max(efficacy)-efficacy(j))/(max(efficacy)-min(efficacy))) ]/2

Compounds with Activity scores > 80% are deemed active, and the activity outcome is set to 2.

Refer to the following recent publication for more detail regarding active compounds:

Identification of 53 compounds that block Ebola virus-like particle entry via a repurposing screen of approved drugs

Jennifer Kouznetsova, Wei Sun, Carles Marti nez-Romero, Gregory Tawa, Paul Shinn, Catherine Z Chen,
Aaron Schimmer, Philip Sanderson, John C McKew, Wei Zheng and Adolfo Garci a-Sastre

Emerging Microbes and Infections (2014) 3, e84; doi:10.1038/emi.2014.88

External ID: Ebola screen1_EMI141217_green

Protocol: This 1536-well plate assay was adapted from the original 6-wells assay with a modification that eliminated cell wash steps. HeLa cells were plated at 750 cells/well in 3 microl of assay medium (DMEM + 10% FBS) in 1536-well assay plates and incubated for 16 hours at 37 degrees C and 5% CO2. Compounds in the 1536-well drug source plates were added to the 1536-well assay plates in a volume of 23 nl/well via a NX-TR pintool station (WAKO Scientific Solutions, San Diego, CA). Following 1-hour incubation at 37 degrees C with 5% CO2, 1 microl/well of VLP solution was added to the assay plates using a BioRapTR FRD dispenser (the VLP solution was diluted in Opti-MEM to a final concentration of 1:16). Plates were then spinoculated by centrifugation at 1500 rpm at 4 degrees C for 45 minutes followed by incubation at 37 degrees C with 5% CO2 for 4.5 hours. The CCF2-AM beta-lactamase substrate was prepared at 6x concentration following the manufacturer's instruction which was added to assay plates at 1 microl/well. Following a 2-hour incubation at room temperature, dual fluorescence intensities (Ex1 = 405+/-20, Em1 = 460+/-20, and Ex2 = 405+/-20, Em2 = 530+/-20 nm) were measured in an EnVision plate reader (PerkinElmer, Boston, MA). The ratio of fluorescence intensities (Em1/Em2) was calculated to represent the beta-lactamase activity that is proportional to the amount of VLP entry into the host cells.

Comment: The activity score was determined using both AC50, Efficacy and curve class. For a given compound j:
Activity is defined as the ability to inhibit viral entry.

If curve class = 4, activity score = 0 and outcome is set to 1. Compounds of this class have no significant activity points.
If efficacy is negative, activity score = 0 and outcome is set to 1. Compounds with negative efficacies, promote viral entry.

For all other curve classes:

Activity score(j) = [100*((max(Ac50)-Ac50(j))/(max(Ac50)-min(Ac50))) + 100*(1-(max(efficacy)-efficacy(j))/(max(efficacy)-min(efficacy))) ]/2

Compounds with Activity scores > 80% are deemed active, and the activity outcome is set to 2.

Refer to the following recent publication for more detail regarding active compounds:

Identification of 53 compounds that block Ebola virus-like particle entry via a repurposing screen of approved drugs

Jennifer Kouznetsova, Wei Sun, Carles Marti nez-Romero, Gregory Tawa, Paul Shinn, Catherine Z Chen,
Aaron Schimmer, Philip Sanderson, John C McKew, Wei Zheng and Adolfo Garci a-Sastre

Emerging Microbes and Infections (2014) 3, e84; doi:10.1038/emi.2014.88

External ID: CHEMBL3137722

Protocol: N/A

Comment: Journal: Gastroenterol Clin Biol
Year: 2004
Volume: 28
Issue: 8-9
First Page: 720
Last Page: 759
DOI: 10.1016/s0399-8320(04)95062-2

Target ChEMBL ID: CHEMBL3879801
ChEMBL Target Name: NON-PROTEIN TARGET
ChEMBL Target Type: NON-MOLECULAR - Target has not been defined at a molecular level, only the non-molecular entity which is affected (e.g., organism, cell line etc)
Relationship Type: N - Non-molecular target assigned
Confidence: Target assigned is non-molecular

External ID: CHEMBL3137723

Protocol: N/A

Comment: Journal: Gastroenterol Clin Biol
Year: 2004
Volume: 28
Issue: 8-9
First Page: 720
Last Page: 759
DOI: 10.1016/s0399-8320(04)95062-2

Target ChEMBL ID: CHEMBL3879801
ChEMBL Target Name: NON-PROTEIN TARGET
ChEMBL Target Type: NON-MOLECULAR - Target has not been defined at a molecular level, only the non-molecular entity which is affected (e.g., organism, cell line etc)
Relationship Type: N - Non-molecular target assigned
Confidence: Target assigned is non-molecular

External ID: DT40657

Protocol: Tox21 Assay Protocol Summary:

300 DT40 mutant cells in 5 uL/well were dispensed into white, solid-bottom 1536-well plates using a Multidrop Combi (ThermoFisher Scientific, Waltham, MA) dispenser. After the assay plates were incubated at 37 C/5% CO2 for approximately 0.5 hour, 23 nL of compounds dissolved in DMSO, positive controls or DMSO only was transferred into the assay plate by a pintool work station (Kalypsys, San Diego, CA). The assay plates were incubated at 37 C/5% CO2 for 40 hours. After 5 uL per well of CellTiter-Glo reagent was added into each well of the assay plates, the plates were incubated for 30 min at room temperature and the luminescence intensity of the plates was measured using a ViewLux (PerkinElmer, Shelton, CT) plate reader.

Comment: Disclaimer:

Although all reasonable efforts have been made to ensure the accuracy and reliability of the data, caution should be exercised when interpreting the results as artifacts are possible from nonspecific effects such as assay signal interference. The curve fitting and activity calls presented here are based on the NCATS analysis methods. Alternative analysis methods and interpretations of the data are available at EPA (http://actor.epa.gov) and NTP (http://tools.niehs.nih.gov/cebs3/ui/).

Compound Ranking:

1. Compounds are first classified as having full titration curves, partial modulation, partial curve (weaker actives), single point activity (at highest concentration only), or inactive. See data field "Curve Description". For this assay, apparent inhibitors are ranked higher than compounds that showed apparent activation.
2. For all inactive compounds, PUBCHEM_ACTIVITY_SCORE is 0. For all active compounds, a score range was given for each curve class type given above. Active compounds have PUBCHEM_ACTIVITY_SCORE between 40 and 100. Inconclusive compounds have PUBCHEM_ACTIVITY_SCORE between 1 and 39. Fit_LogAC50 was used for determining relative score and was scaled to each curve class' score range.

External ID: CHEMBL3137724

Protocol: N/A

Comment: Journal: Gastroenterol Clin Biol
Year: 2004
Volume: 28
Issue: 8-9
First Page: 720
Last Page: 759
DOI: 10.1016/s0399-8320(04)95062-2

External ID: Ebola screen1_EM141217_blue

Protocol: This 1536-well plate assay was adapted from the original 6-wells assay with a modification that eliminated cell wash steps. HeLa cells were plated at 750 cells/well in 3 microl of assay medium (DMEM + 10% FBS) in 1536-well assay plates and incubated for 16 hours at 37 degrees C and 5% CO2. Compounds in the 1536-well drug source plates were added to the 1536-well assay plates in a volume of 23 nl/well via a NX-TR pintool station (WAKO Scientific Solutions, San Diego, CA). Following 1-hour incubation at 37 degrees C with 5% CO2, 1 microl/well of VLP solution was added to the assay plates using a BioRapTR FRD dispenser (the VLP solution was diluted in Opti-MEM to a final concentration of 1:16). Plates were then spinoculated by centrifugation at 1500 rpm at 4 degrees C for 45 minutes followed by incubation at 37 degrees C with 5% CO2 for 4.5 hours. The CCF2-AM beta-lactamase substrate was prepared at 6x concentration following the manufacturer's instruction which was added to assay plates at 1 microl/well. Following a 2-hour incubation at room temperature, dual fluorescence intensities (Ex1 = 405+/-20, Em1 = 460+/-20, and Ex2 = 405+/-20, Em2 = 530+/-20 nm) were measured in an EnVision plate reader (PerkinElmer, Boston, MA). The ratio of fluorescence intensities (Em1/Em2) was calculated to represent the beta-lactamase activity that is proportional to the amount of VLP entry into the host cells.

Comment: The activity score was determined using both AC50, Efficacy and curve class. For a given compound j:
Activity is defined as the ability to inhibit viral entry.

If curve class = 4, activity score = 0 and outcome is set to 1. Compounds of this class have no significant activity points.
If efficacy is negative, activity score = 0 and outcome is set to 1. Compounds with negative efficacies, promote viral entry.

For all other curve classes:

Activity score(j) = [100*((max(Ac50)-Ac50(j))/(max(Ac50)-min(Ac50))) + 100*(1-(max(efficacy)-efficacy(j))/(max(efficacy)-min(efficacy))) ]/2

Compounds with Activity scores > 70% are deemed active, and the activity outcome is set to 2.

Note that this scoring scheme only applies to the ratio of blue/green fluorescence intensities because it is this ratio that represents the activity of Bla inside cells. Separate uploads of blue and green data exist in this assay group but information on activity should not be derived from these.

Refer to the following recent publication for more detail regarding active compounds:

Identification of 53 compounds that block Ebola virus-like particle entry via a repurposing screen of approved drugs

Jennifer Kouznetsova, Wei Sun, Carles Marti nez-Romero, Gregory Tawa, Paul Shinn, Catherine Z Chen,
Aaron Schimmer, Philip Sanderson, John C McKew, Wei Zheng and Adolfo Garci a-Sastre

Emerging Microbes and Infections (2014) 3, e84; doi:10.1038/emi.2014.88