olomoucine ii

Olomoucine II is an inhibitor of cyclin-dependent kinases (CDKs; IC50s = 7.6, 0.1, 19.8, 0.45, and 0.06 μM for Cdk1, -2, -4, -7, and -9, respectively).1It is selective for CDKs over 10 additional kinases (IC50s = >100 μM for all) but does inhibit ERK2 (IC50= 32 μM) and the ATP-binding cassette transporter B1 (ABCB1; IC50= 6.4 μM).1,2Olomoucine II inhibits proliferation of a variety of cancer cells, including those expressing wild-type p53 or mutant p53 (mean IC50s = 7.4 and 10.1 μM, respectively), and it acts synergistically with daunorubicin to inhibit proliferation of HCT-8 cells that endogenously express ABCB1. Olomoucine also inhibits replication of herpes simplex virus 1 (HSV-1), HSV-2, vaccinia virus, human adenovirus type 4 (Ad4), and human CMV (IC50s = 5, 4.7, 3.8, 2.4, and 3.2 μM, respectively) but not measles virus or influenza virus (IC50s = >20 μM for both).3

Ibulocydine is a potent CDK inhibitor. Ibulocydine has high activity against Cdk7 cyclin H Mat1 and Cdk9 cyclin T. Ibulocydine inhibited the growth of HCC cells more effectively than other Cdk inhibitors, including olomoucine and roscovitine, whereas ibulocydine as well as the other Cdk inhibitors and BMK-Y101 minimally influenced the growth of normal hepatocyte cells. Ibulocydine induced apoptosis in HCC cells, most likely by inhibiting Cdk7 and Cdk9. In vitro treatment of HCC cells with ibulocydine rapidly blocked phosphorylation of the carboxyl-terminal domain (CTD) of the large subunit of RNA polymerase II, a process mediated by Cdk7 9. Anti-apoptotic gene products such as Mcl-1, survivin, and X-linked IAP (XIAP) are crucial for the survival of many cell types, including HCC. Following the inhibition of RNA polymerase II phosphorylation, ibulocydine caused rapid down-regulation of Mcl-1, survivin, and XIAP, thus inducing apoptosis. Furthermore, ibulocydine effectively ind......