PP121

PP121 is a multi-targeted kinase inhibitor with IC50s of 10, 60, 12, 14, 2 nM for mTOR, DNK-PK, VEGFR2, Src, PDGFR, respectively.

Signaling Pathways >> Protein Tyrosine Kinase/RTK >> Src

Research Areas >> Cancer

mTOR:10 nM (IC50)

PDGFR:2 nM (IC50)

VEGFR2:12 nM (IC50)

Src:14 nM (IC50)

DNK-PK:60 nM (IC50)

PP121 blocks the PI3K pathway by direct inhibition of PI3K/mTOR in two glioblastoma cell lines, U87 and LN229. PP121 potently inhibits the proliferation of a diverse panel of tumor cell lines containing mutations in the PI3-K pathway components PIK3CA, PTEN, or RAS. PP121 induces a G0G1 arrest in most tumor cells. PP121 directly inhibits Src in cells and reverses its biochemical and morphological effects. PP121 potently inhibits the Ret kinase domain in vitro (IC50<1 nM). PP121 potently blocks VEGF stimulated activation of the PI3-K and MAPK pathways. PP121 inhibits VEGFR2 autophosphorylation at low nanomolar concentrations, confirming that this molecule directly targets VEGFR2 in cells. PP121 inhibits Bcr-Abl induced tyrosine phosphorylation in K562 cells as well as BaF3 cells that express Bcr-Abl[1].

Oral administration of PP121 remarkably inhibits Eca-109 xenograft growth. Mice body weights are not significantly affected by PP121 or the vehicle treatment. PP121 oral administration dramatically inhibits activations of Akt-mTOR and NFkB in xenograft tumors. p-Akt Ser 473 and p-IKKa/b are both inhibited by PP121 administration[2].

Purified kinase domains are incubated with inhibitors (PP121) at 2- or 4-fold dilutions over a concentration range of 50- 0.001 µM or with vehicle (0.1% DMSO) in the presence of 10 µM ATP, 2.5 µCi of γ- 32P-ATP and substrate. Reactions are terminated by spotting onto nitrocellulose or phosphocellulose membranes, depending on the substrate; this membrane is then washed 5-6 times to remove unbound radioactivity and dried. Transferred radioactivity is quantitated by phosphorimaging and IC50 values are calculated by fitting the data to a sigmoidal doseresponse using Prism software[1].

Cells grown in 96-well plates are treated with PP121 at 4-fold dilutions (10 µM - 0.040 μM) or vehicle (0.1% DMSO). After 72 h cells are exposed to Resazurin sodium salt (22 µM) and fluorescence is quantified. IC50 values are calculated. For proliferation assays involving single cell counting, non-adherent cells are plated at low density (3–5% confluence) and treated with drug (2.5 µM) or vehicle (0.1% DMSO). Cells are diluted into trypan blue daily and viable cells counted using a hemocytometer[1].

Mice: Eca-109 cells are injected into the axillary regions of nude mice (5×106 cells/mouse). When the tumor volumes reach around 200 mm3, the mice are randomly separated to three groups: Untreated control, PP121 (30 mg/kg) and vehicle (10% 1-methyl-2-pyrrolidinone and 90% PEG 300) group. Tumor volumes and the mice body weights are measured every 10 d[2].

[1]. Apsel B, et al. Targeted polypharmacology: discovery of dual inhibitors of tyrosine and phosphoinositide kinases. Nat Chem Biol, 2008, 4(11), 691-699.

[2]. Peng Y, et al. The anti-esophageal cancer cell activity by a novel tyrosine/phosphoinositide kinase inhibitor PP121. Biochem Biophys Res Commun. 2015 Sep 11;465(1):137-44.

Rapamycin (Sirolimus) | Nintedanib (BIBF 1120) | Torin 1 | SU5416 | MHY1485 | Sapanisertib (MLN0128) | AZD8055 | Dactolisib (BEZ235) | Apatinib Mesylate | Saracatinib | Crenolanib | Vistusertib (AZD2014) | PD173074 | PP2 (AG 1879) | Foretinib (GSK1363089)