GSK3B and prostate cancer: Specifically, we discovered that IL-24 activates PKA in human prostate cancer cells, induces GSK3β phosphorylation in serine 9 and threonine 390, thereby inactivating its kinase activity, and IL-24-dependent phosphorylation of GSK3β is necessary to mediate apoptosis in human prostate cancer cells through an intrinsic apoptotic pathway.