Indisulam (E 7070) is a carbonic anhydrase inhibitor and antitumor CDK inhibitor that targets the G1 phase of the cell cycle by depleting cyclin E, inducing p53 and p21, and inhibiting CDK2, thereby causing a blockade in the G1/S transition.

In vitro, indisulam has antiproliferative effects on a wide range of human tumor lines with HCT116 colorectal being the most sensitive and NCI-H596 non-small cell lung cancer (NSCLC) the most resistant (IC50s = 0.11 and 94 μg/ml, respectively). It increases the number of P388 murine leukemia cells in the G1 phase of the cell cycle in a dose-dependent manner and exerts time-dependent cytotoxicity against HCT116 cells.

In vivo, indisulam suppresses tumor growth and decreases tumor volume in murine HCT116, SW620, and HCT15 colorectal and LX-1 and PC9 lung cancer xenograft models. Indisulam induces proteasomal degradation of RNA binding motif protein 39 (RBM39) through association with the CUL4-DCAF15 E3 ubiquitin ligase in vitro.It is also an inhibitor of carbonic anhydrase in H. pylori (Ki = 310-562 nM). Formulations containing indisulam are under Clinicalal investigation for the treatment of solid tumors.