GB-3103

GB-3103 is a potent and selective small molecule inhibitor of histone deacetylase 3 (HDAC3), with a reported IC50 of approximately 0.56 nM. Developed for the treatment of neuroendocrine cancers, including neuroendocrine prostate cancer (NEPC) and small cell lung cancer (SCLC), GB-3103 functions by inducing a state of "BRCAness" in tumor cells. This phenotype is characterized by the suppression of genes responsible for DNA damage repair and the maintenance of genomic stability, which sensitizes the tumors to poly (ADP-ribose) polymerase (PARP) inhibitors. Preclinical studies have demonstrated that GB-3103 inhibits PI3K-AKT1, MYC, and p53 signaling pathways and shows robust synergistic antitumor activity when combined with PARP inhibitors like olaparib or talazoparib in xenograft models.