Clinically relevant GSK­3ß inhibitor 9­ING­41 is active as a single agent and in combination with other antitumor therapies in human renal cancer.

Glycogen synthase kinase­3 (GSK­3), a serine/threonine kinase, is involved in a broad range of pathological processes including cancer. GSK­3 has two isoforms, GSK­3α and GSK­3ß, and GSK­3ß has been recognized as a therapeutic target for the development of new anticancer drugs. The present study aimed to investigate the antitumor effects of 9­ING­41, which is a maleimide­based ATP­competitive small molecule GSK­3ß inhibitor active in patients with advanced cancer. In renal cancer cell lines, treatment with 9­ING­41 alone induced cell cycle arrest and apoptosis, and autophagy inhibitors increased the antitumor effects of 9­ING­41 when used in combination. Treatment with 9­ING­41 potentiated the antitumor effects of targeted therapeutics and increased the cytotoxic effects of cytokine­activated immune cells on renal cancer cell lines. These results provided a compelling rationale for the inclusion of patients with renal cancer in studies of 9­ING­41, both as a single agent and in combination with current standard therapies.