A 83586C is a depsipeptide antibiotic from Streptomyces karnatakensis that shows potent Gram-positive activity in vitro. It functions as a highly potent inhibitor of beta-cateniTCF4 signaling within cancer cells, while simultaneously downregulating osteopontin (Opn) expression. A83586C antitumor cyclodepsipeptides also inhibit E2F-mediated transcription by downregulating E2F1 expression and inducing dephosphorylation of the oncogenic hyperphosphorylated retinoblastoma protein (pRb).
