西达本胺诱导多发性骨髓瘤细胞凋亡及与DNA损伤反应的相关性

Inducing Effect of Chidamide on Apoptosis of Multiple Myeloma Cells and Its Relerance to DNA Damage Response

目的:本研究旨在探讨新型组蛋白脱乙酰酶抑制剂(HDACi)西达本胺对人多发性骨髓瘤(MM)细胞凋亡的影响及其与DNA损伤反应(DDR)的相关性。方法:采用MTT法检测西达本胺对MM细胞系RPMI8226的增殖抑制作用;应用流式细胞术分析靶细胞凋亡及细胞周期分布;采用Western blot检测靶细胞目标蛋白表达;应用ATM激酶特异性抑制剂KU-55933干扰DDR过程。结果:西达本胺对RPMI 8226细胞的增殖抑制作用呈时间剂量依赖性,其24、48和72 h IC50值分别为9.6,6和2.8μmol/L。西达本胺通过上调RPMI 8226细胞p21蛋白表达,将细胞周期阻滞于G0/G1期。西达本胺通过caspase-3依赖的途径诱导RPMI8226细胞凋亡,并上调DDR相关蛋白γH2AX和p ATM的表达。采用ATM激酶抑制剂KU-55933预处理靶细胞,可下调西达本胺诱导的γH2AX和p ATM蛋白表达升高,从而抑制DNA损伤反应,并逆转西达本胺诱导的细胞凋亡。结论:西达本胺诱导骨髓瘤细胞增殖抑制、细胞周期停滞和细胞凋亡涉及DNA损伤反应。

Objective： This study was aimed to explore the effect of a novel histone deacetylase inhibitor Chidamide on apoptosis of human multiple myeloma （MM） cells and its relevance to DNA damage response （DDR）. Methods： The cell proliferation was detected by MTT method, apoptosis and cell cycle distribution were analyzed by flow cytometry, the expression levels of targeted proteins were detected by Western blot, the DNA damage response was blocked by ATM kinase inhibitor KU-55933. Results： Chidamide inhibited RPMI 8226 cell proliferation in dose- and time-depend- ent manner and its IC50 values of 24,48,72 h were 9.6, 6 and 2.8μmol/L respectively. Chidamide induced cell cycle arrest of RPMI 8226 cells in G0/G1 phase by upregulating the expression of P21. Chidamide triggered caspase-3 dependent apoptosis and upregulated expression of DDR-related proteins including 3,H2AX, pATM in RPMI 8226 cells. Pretreatment with ATM kinase inhibitor KU-55933 down-regulated expression of DDR related proteins induced by chidamide, thereby inhibiting DNA damage response and finally resulting in suppression of apoptotic cell death. Conclusion： Proliferative inhibtion, cell cycle arrest and apoptosis of multiple myeloma cells induced bv chidamide involve DDR.