OSU-03012 (AR-12)

460, 45

Huh7 tumor xenografts in male BALB/c nude mice

0-10 uM

Dissolved in 0.5% methylcellulose, 0.1% Tween 80

OSU-03012 induces apoptotic death in PC-3 cells with IC50 of 5 uM and reduces the activity of immunoprecipitated p70S6K. OSU-03012 completely suppress cell growth in a diverse range of tumor cell lines at concentrations of 3–5 um, as compared with the concentration of at least 50 um required for celecoxib. [1] OSU-03012 promotes cell killing to a greater extent in glioma cells than in nontransformed astrocytes. OSU-03012 causes a dose-dependent induction of cell death that is not altered by p53 mutation, expression of ERBB1 VIII, or loss of phosphatase and tensin function due to a homolog deletion on chromosome 10. OSU-03012 and ionizing radiation cause an additive, caspase-independent elevation in cell killing. OSU-03012 lethality as a single agent or when combined with signaling modulators is not modified in cells lacking expression of BIM or of BAX/BAK. OSU-03012 promotes the release of cathepsin B from the lysosomal compartment and that of AIF from mitochondria. The lethality of OSU-03012 is attenuatedn protein kinase R-like endoplasmic reticulum kinase-/- cells, which correlated with the reduced cleavage of BID and suppression of cathepsin B and AIF release into the cytosol. [2] OSU-03012 inhibits thyroid cancer cell (NPA, WRO, and ARO cells) proliferation, migration and induces apoptosis, which results in an increase of cells in the S phase without an increase of cells in G2. OSU-03012 is an ATP-competitive inhibitor of PAK activity and suppresses the phosphorylation of AKT in thyroid cancer cells. [3] OSU-03012 inhibits cell growth of hepatocellular carcinoma cell lines including Huh7, Hep3B and HepG2 cells with IC50 values below 1 uM. OSU-03012 does not suppress PDK1 or AKT activity or induce cellular apoptosis but induces autophagy in Huh7 cells. Moreover, accumulation of reactive oxygen species (ROS) is detected after OSU-03012 treatment. [4] A recent study shows that OSU-03012 could enhance the susceptibility of (Bcr)-Abl mutant cell lines to imatinib-induced apoptosis. [5]

ca.72 hours

The effect of OSU-03012 on PC-3 cell viability is assessed by using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-2H-tetrazolium bromide assay in six replicates. Cells are grown in 10% FBS- supplemented RPMI 1640 in 96-well, flat-bottomed plates for 24 hours. They are exposed to various concentrations of OSU-03012 (0-10 uM) dissolved in DMSO (final concentration <=0.1%) in 1% serum-containing RPMI 1640 for different time intervals (ca.72 hours). Controls receive DMSO vehicle at a concentration equal to that in OSU-03012-treated cells. The medium is removed and replaced by 200 uL of 0.5 mg/mL 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-2H-tetrazolium bromide in 10% FBS-containing RPMI 1640. The cells are incubated in the CO2 incubator at 37 C for 2 hours. Supernatants are removed from the wells, and the reduced 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-2H-tetrazolium bromide dye is solubilized in 200 uL DMSO per well. Absorbance at 570 nm is determined by using a plate reader.

OSU-03012 (AR-12) is a potent inhibitor of recombinant PDK-1(phosphoinositide-dependent kinase 1) with IC50 of 5 μM in a cell-free assay and 2-fold increase in potency over OSU-02067.

OSU-03012 is a derivative of celecoxib and shows ten-fold greater antitumor activity than celecoxib but it lacks its COX-2 inhibitory activity.