Induction Of K562A02 Cell Proliferation,Apoptosis And Drug Resistance By Regulating Heme Oxygenase-1 And The Underlying Mechanism

Objective: in this study, we induced HO-1 expression by Hemin or inhibited HO-1 by ZNPP while treating K562A02 cells with adriamycin, so as to investigate the mechanism of chemoresistance of chronic myeloid leukemia(CML) and Provide a new strategy reversal of drug resistance. Methods: K562 and K562A02 cells were cultured and expression of bcr-abl fusion gene in K562A02 cells was analyzed by fluorescence in situ hybridization(FISH). Inhibition of K562 and K562A02 cell proliferation after adriamycin treatment was determined by MTT assay, and the relative chemoresistance was calculated as the ratio of IC50 values. Then HO-1 was induced by Hemin or inhibited by ZNPP while treating K562A02 cells with different concentrations of adriamycin, followed by MTT assay 24 h, 28 h, 72 h later to determine inhibition rate of K562A02 cell proliferation,To detect induced apoptosis by flow cytometry. Flow cytometry to determine apoptosis rate of the treated cells. Results: 92% of the K562A02 cells had positive bcr-abl fusion protein expression as indicated by FISH assay. IC50 values of adriamycin for K562 and K562A02 cells were 12.320±1.720 ug/ml and 24.742±2.310 ug/ml respectively, MTT methods showed that Adriamycin inhibited the proliferation of K562A02 cells in a dose and time-dependent manner.Real-time PCR and Western blot methods showed that the m RNA and protein expressions of drug-resistance genes,MDR1,NF-κB, MRP1, Topo IIα, and ABCD2, decreased after Adriamycin treatment. Hemin and zinc protoporphyrin IX were used to treat K562A02 cells with Adriamycin, once HO-1 expression was up-regulated, the expressions of drug-resistance related genes increased, apoptotic rate of K562A02 cells reduced as well. While the down-regulation of HO-1 could active the expresson of drug-resistance related genes and increase the apoptotic rate of K562A02 cells. Conclusion: Adriamycin is able to inhibit proliferation and induce apoptosis in K562/A02 cells in dose-dependent and time-dependent manner. When the target gene HO-1 is upregulated, adriamycin resistance of K562A02 cells will be enhanced to promote proliferation and induce apoptosis. When the target gene HO-1 is down-regulated, adriamycin sensitivity of K562A02 cells will be enhanced to inhibit proliferation and induce apoptosis, thus achieve the goal of reversing adriamycin resistance.HO-1 can act as a target gene for drug resistance reversal to regain adriamycin sensitivity in K562A02 cells.