Effect Of Curcumin Derivative C085on Chronic Myelogenous Leukemia Cells

Background and Objective:BCR-ABL, a protein tyrosine kinase (PTK), has continuously PTK activity which is closely related with pathogenesis of CML and represents an important molecular targets in CML remedy[1,2]. Imatinib (IM,Gleeve,STI571), a typical anti-cancer drug that inhibit BCR-ABL kinase activity in CML cells, shows resistance because of mutation and activity increasing of BCR-ABL kinase[3], which point out that a new BCR-ABL inhibitor is needed.Curcumin (Cur) has dramatic anti-cancer activity by inducing BCR-ABL+CML cells apoptosis and maybe has particular therapy value[4]. However, one potential problem with the clinical use of Cur is its low water solubility> obvious first pass elimination and poor systemic bioavailability [5]. C085, a new Cur derivative synthesized by our lab, which had been verified that binding to BCR-ABL kinase in different sites from IM by computer simulations, showed significantly inhibition on the proliferation of both IM sensitive and resistant leukemia cell lines, and the IC50values were3-fold lower than that of curcumin’s. On this basis, this research aimed to clarify the relationship between the anti-leukemia effect of C085and its regulations on the kinase activities of both wild type and mutant type of ABL kinase, and to find an effective PTK inhibitor of IM resistant mutant ABL kinase.Methods:1.MTT method and trypan blue stain assay were used to determine the anti-proliferative effects of C085on leukemia cells; FITC-Annexin-V/PI was used to determine the apoptosis and western blot was used to investigate the signal protein;2. Colony formation assay was used to observe C085’s effect on the proliferation of CD34+cells in CML patients’bone marrow.3. Kinase Assay kit was used to detect the effect of C085on Abl kinase activity.4. The change of mitochondrial membrane potential on leukemia cells was detected by JC-1fluorescent staining.Results:1. C085can significantly inhibit the proliferation of IM sensitive and resistant leukemia cell lines with a dose-dependent manner, and the IC50values were about3-fold lower than that of Cur. C085fully inhibited the growth of K562/G01cells for72h, which IM had no significant effect. C085induced significant apoptosis in24h, which was better than IM.2. C085and Cur decreased the colony formation of CML CD34+cells from IM drug-resistant CML patients.3. C085inhibited the activity of Abl kinase of both wild type and IM resistance point mutant type with non-ATP competition.4. C085down-regulated the abundance and phosphorylation of P210Bcr-abl as well as the downstream signal proteins in K562cells, which were stronger than IM. Apoptosis-associated proteins cleaved-PARP、cleaved-caspase3and cleaved-caspase9were obviously up-regulated at low dose of C085, and the regulation on Bax, Bcl-2were stronger than IM, too.5. C085can directly impact mitochondrial PT hole and make it open, which were better than IMConclusion:C085inhibited BCR-ABL+CML cells through inhibiting BCR-ABL kinase activity and down-regulating the downstream signal proteins. Direct action on mitochondrial PT hole and then activating apoptosis-associated proteins was also involved in the pro-apoptotic effect of C085.