VS-5584 (SB2343) is a pan-PI3K/mTOR kinase inhibitor.

PI3Kδ:2.7 nM, PI3Kβ:21 nM, PI3Kα:2.6 nM, PI3Kγ:3.0 nM, mTOR:3.4 nM

VS-5584 is an ATP-competitive inhibitor which selectively inhibits PI3K/mTOR signaling with equivalent low nanomolar potency against all human Class I PI3K isoforms and mTOR kinase. VS-5584 is approximately 10-fold selective for cancer stem cells with an EC50 of 15 nM in HMLE breast cancer cells. VS-5584 preferentially decreases CD44Hi/CD24Lo cells in an HMLER immortalized mammary cancer cell line. In SUM159 cells, VS-5584 effectively eliminates the cancer stem cell side population. [1] A large human cancer cell line panel screen (436 lines) reveals broad antiproliferative sensitivity and that cells harboring mutations in PI3KCA are generally more sensitive toward VS-5584 treatment. In the FLT3-ITD harboring MV4-11 cells, VS-5584 blocks pAkt (S473) and pAkt (T308) with IC50 of 12 and 13 nM, respectively. The IC50 of VS-5584 for pS6 (S240/244), pAkt (S473), and pAkt (T308) are 20, 23, and 15 nM, respectively. [2]

In mice bearing triple negative breast cancer tumors, oral dosing of VS-5584 decreases tumor cancer stem cells and induces tumor regression in taxane-resistant models. [1] In a PTENnull human prostate PC3 xenograft model, treatment with VS-5584 leads to significant tumor growth inhibition (TGI) of 79% and 113% for 11 and 25 mg/kg, respectively. In a FLT3-ITD AML xenograft model, VS-5584 treatment induces dose-dependent inhibition of tumor growth (28% for 3.7 mg/kg and 76% for 11 mg/kg). [2]

In vitro mTOR kinase assays : The reaction mixture consisted of the following components in 10 μL assay buffer (50 mM Hepes pH 7.5, 10 mM MgCl 2, 3 mM MnCl 2, 1 mM EGTA, 2 mM DTT, 0.01%Tween-20): 0.10 μg/mL of in-house generated mTOR enzyme, 0.05 μM ULight-eIF4E-binding protein 1 (Thr37/46) peptide and 10 μM ATP. The mixture is incubated for 60 min at room temperature. 10 μL of Detection mixture consisted of 16 mM EDTA, 0.004 mM Eu-W1024-labeled Anti-Phospho-eIF4E-binding protein 1-(Thr37/46) antibody and 1X LANCE? Detection Buffer is then added and incubated for 60 min.

CellTiter-Glo assay(Only for Reference)