CDK9-IN-15 is a potent small molecule CDK9 inhibitor, which can block the phosphorylation of positive transcription elongation factor b (P-TEFb) on the C-terminal region of RNA Poly-II by degradation and inhibition of CDK9, inhibit transcription, and rapidly reduce the level of intracellular mRNA, thereby causing apoptosis of tumor cells.

A potent CDK2 inhibitor with IC50 of 47 nM; also inhibits CDK1/4/5 with IC50 of 190/67/18 nM and shows selectivity over some kinases (Aurora A, IR kinase, MEK, PDK1, c-Abl, IC50>10 uM).

Indisulam (E7070) is potent, sulfonamide, cell-cycle inhibitor that possesses antiproliferative activities, causes decrease in the S phase fraction along with G1 and/or G2 accumulation in various cancer cell lines.