OSI-027

OSI-027 is an ATP-competitive mTOR kinase activity inhibitor with an IC50 of 4 nM. OSI-027 targets both mTORC1 and mTORC2 with IC50s of 22 nM and 65 nM, respectively.

Signaling Pathways >> Autophagy >> Autophagy

Signaling Pathways >> PI3K/Akt/mTOR >> mTOR

Research Areas >> Cancer

mTORC1:22 nM (IC50)

mTORC2:65 nM (IC50)

mTOR:4 nM (IC50)

PI3K-γ:0.42 μM (IC50)

PI3K-α:1.3 μM (IC50)

DNA-PK:1 μM (IC50)

Autophagy

OSI-027 is an ATP-competitive inhibitor, which targets both mTORC1 and mTORC2 with IC50s of 22 nM and 65 nM. OSI-027 also inhibits PI3K-α, PI3K-γ and DNA-PK with IC50s of 1.3 μM, 0.42 μM and 1.0 μM. OSI-027 inhibits mTOR signaling of phospho-4E-BP1 with an IC50 of 1 μM[1].

Effects on GEO colorectal xenograft growth treated with Rapamycin or OSI-027 for 12 days are consistent with our in vitro experiments. Treatment with Rapamycin (20 mg/kg) inhibits phospho-S6 and phospho-4E-BP1, while Akt phosphorylation is increased by 29%. In contrast, OSI-027 (65 mg/kg) inhibits both mTORC1 and mTORC2 effectors. After 2 hours, decreased 4E-BP1, Akt, and S6 phosphorylation is observed and inhibition of S6 and Akt is sustained for 24 hours. The plasma drug concentration of OSI-027 inversely correlated with these effects on mTORC1 and mTORC2 signaling. The median plasma drug concentration with OSI-027 is 21.3 μM at 2 hours and 14.9 μM at 8 hours. The in vivo efficacy of OSI-027 plus Sunitinib is tested in H292 human lung and Ovcar-5 human ovarian xenograft tumors. H292 tumors, treated with OSI-027 (50 mg/kg) for 21 days have 61% median tumor growth inhibition for the duration of treatment (TGI). Sunitinib (40 mg/kg) for 21 days had 47% median TGI. Combining OSI-027 with Sunitinib, however, has a median TGI of 100% with 59% maximal tumor regression, a statistically significant improvement over either agent alone. Ovcar-5 xenograft tumors treated with OSI-027 or Sunitinib have a 55% and 68% median TGI, respectively. OSI-027 administered with Sunitinib has a significantly better median TGI of 100% with 38% maximal tumor regression[1].In the Rapamycin (RAPA) group, three rats exhibit symptoms typical of LTx-aGVHD and die 27 to 35 days after liver transplantation (LT); the remaining five rats do not develop LTx-aGVHD symptoms and survive for more than 100 days. In contrast, seven rats in the OSI-027 group survive for more than 100 days without symptoms of LTx-aGVHD, and only one rat exhibits LTx-aGVHD symptoms and dies on day 33 after LT[2].

Assays of a panel of 40 other recombinant kinases including both protein and lipid kinases are performed at 100 mM ATP concentration by SelectScreen profiling service. A broad panel of kinases is tested at a single concentration of OSI-027 or OXA-01 (3 μM) to evaluate percent inhibition of each kinase or mutant variant, using the Ambit KinomeScan platform[1].

To study the effect of drug treatment on cellular signaling, Ovcar-3 cells are plated in normal growth medium. After 24 hours, serum is removed and cells are serum-starved overnight. Rapamycin, OSI-027 and OXA-01 are solubilized in DMSO and added to cells at varying concentrations. After a two-hour incubation cells are growth factor stimulated with 10 ng/mL Insulin for 3 to 5 minutes, then rinsed with cold PBS and lysed[1].

Mice[1] For xenograft models, cells are harvested, implanted s.c. in the right flank of nu/nu CD-1 mice and tumor growth is analyzed. Mice bearing GEO xenografts are treated for 12 days with OSI-027 (65mg/kg) or vehicle and tumors collected at 2, 8, and 24 hours. Tumor growth inhibition and regression calculations are included. Rats[2] Specific pathogen-free female Lewis rats, male BN rats, male Lew-Tg(CAG-EGFP)YsRrrc rats and male Lew-TgYsRrrc rats are used. Orthotopic LT is undertaken. No antibiotics were used. Freshly prepared splenocytes (4×108, suspended in 500 μL PBS) of Lew-Tg YsRrrc rats are infused into each recipient via the dorsal penile vein immediately after LT (within 30 min). LTx-aGVHD model rats are divided into three experimental groups: RAPA (1 mg/kg), OSI-027 (1 mg/kg) or control (equal quantity of vehicle) groups; treatments are administered via the vena caudalis from day 7 to day 15.

[1]. Falcon BL, et al. Reduced VEGF production, angiogenesis, and vascular regrowth contribute to the antitumor properties of dual mTORC1/mTORC2 inhibitors. Cancer Res. 2011 Mar 1;71(5):1573-83.

[2]. Zhi X, et al. OSI-027 modulates acute graft-versus-host disease after liver transplantation in a rat model. Liver Transpl. 2017 Sep;23(9):1186-1198.

[3]. Zhang Y, et al. PP2AC Level Determines Differential Programming of p38-TSC-mTOR Signaling and Therapeutic Response to p38-Targeted Therapy in Colorectal Cancer. EBioMedicine. 2015 Nov 19;2(12):1944-56.

Rapamycin (Sirolimus) | Torin 1 | MHY1485 | Sapanisertib (MLN0128) | AZD8055 | Dactolisib (BEZ235) | Vistusertib (AZD2014) | Torkinib (PP242) | LY3023414 | Torin 2 | GSK2126458(GSK458) | PF-04691502 | Salidroside | PQR-309 | PI-103