Benastatin A is a polyketide synthase-derived benastatin that has been found inStreptomycesand has diverse biological activities.1,2,3It inhibits glutathione S-transferase (GST; Ki= 5 μM for the rat liver enzyme).2Benastatin A is active against several bacteria, including methicillin-resistantS. aureus(MRSA; MIC = 3.12 μg ml). It induces apoptosis and cell cycle arrest at the G1 G0phase in Colon 26 mouse colon cancer cells when used at concentrations of 20 and 16 μM, respectively.3 1.Xu, Z., Schenk, A., and Hertweck, C.Molecular analysis of the benastatin biosynthetic pathway and genetic engineering of altered fatty acid-polyketide hybridsJ. Am. Chem. Soc.129(18)6022-6030(2007) 2.Aoyagi, T., Aoyama, T., Kojima, F., et al.Benastatins A and B, new inhibitors of glutathione S-transferase, produced by Streptomyces sp. MI384-DF12. I. Taxonomy, production, isolation, physico-chemical properties and biological activitiesJ. Antibiot. (Tokyo)45(9)1385-1390(1992) 3.Kakizaki, I., Ookawa, K., Ishikawa, T., et al.Induction of apoptosis and cell cycle arrest in mouse colon 26 cells by benastatin AJpn. J. Cancer Res.91(11)1161-1168(2000)
Benastatin C is a polyketide synthase-derived benastatin that has been found inStreptomycesand has diverse biological activities.1,2It inhibits glutathione S-transferase (GST; IC50= 24 μg ml for the rat liver enzyme).2Benastatin C also inhibits the esterase activity of isolated porcine pancreatic lipase (IC50= 10 μg ml). It increases LPS- or concanavalin A-induced blastogenesis of isolated mouse spleen lymphocytes in a concentration-dependent manner. 1.Xu, Z., Schenk, A., and Hertweck, C.Molecular analysis of the benastatin biosynthetic pathway and genetic engineering of altered fatty acid-polyketide hybridsJ. Am. Chem. Soc.129(18)6022-6030(2007) 2.Aoyama, T., Kojima, F., Yamazaki, T., et al.Benastatins C and D, new inhibitors of glutathione S-transferase, produced by Streptomyces sp. MI384-DF12. Production, isolation, structure determination and biological activitiesJ. Antibiot. (Tokyo)46(5)712-718(1993)
AP23464 is a potent adenosine 5'-triphosphate (ATP)-based inhibitor of Src and Abl kinases, displays antiproliferative activity against a human CML cell line and Bcr-Abl-transduced Ba F3 cells (IC(50) = 14 nM. AP23464 ablates Bcr-Abl tyrosine phosphorylation, blocks cell cycle progression, and promotes apoptosis of Bcr-Abl-expressing cells. Biochemical assays with purified glutathione S transferase (GST)-Abl kinase domain confirmed that AP23464 directly inhibits Abl activity. Importantly, the low nanomolar cellular and biochemical inhibitory properties of AP23464 extend to frequently observed imatinib mesylate-resistant Bcr-Abl mutants, including nucleotide binding P-loop mutants Q252H, Y253F, E255K, C-terminal loop mutant M351T, and activation loop mutant H396P. AP23464 was ineffective against mutant T315I, an imatinib mesylate contact residue. The potency of AP23464 against imatinib mesylate-refractory Bcr-Abl and its distinct binding mode relative to imatinib mesylate warr......