Kiziltepe Tanyel, Hideshima Teru, Catley Laurence, Raje Noopur, Yasui Hiroshi, Shiraishi Norihiko, Okawa Yutaka, Ikeda Hiroshi, Vallet Sonia, Pozzi Samantha, Ishitsuka Kenji, Ocio Enrique M, Chauhan Dharminder, Anderson Kenneth C
Jerome Lipper Multiple Myeloma Center, Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts 02115, USA.
Mol Cancer Ther. 2007 Jun;6(6):1718-27. doi: 10.1158/1535-7163.MCT-07-0010.
In this study, we investigated the cytotoxicity of 5-azacytidine, a DNA methyltransferase inhibitor, against multiple myeloma (MM) cells, and characterized DNA damage-related mechanisms of cell death. 5-Azacytidine showed significant cytotoxicity against both conventional therapy-sensitive and therapy-resistant MM cell lines, as well as multidrug-resistant patient-derived MM cells, with IC(50) of approximately 0.8-3 micromol/L. Conversely, 5-azacytidine was not cytotoxic to peripheral blood mononuclear cells or patient-derived bone marrow stromal cells (BMSC) at these doses. Importantly, 5-azacytidine overcame the survival and growth advantages conferred by exogenous interleukin-6 (IL-6), insulin-like growth factor-I (IGF-I), or by adherence of MM cells to BMSCs. 5-Azacytidine treatment induced DNA double-strand break (DSB) responses, as evidenced by H2AX, Chk2, and p53 phosphorylations, and apoptosis of MM cells. 5-Azacytidine-induced apoptosis was both caspase dependent and independent, with caspase 8 and caspase 9 cleavage; Mcl-1 cleavage; Bax, Puma, and Noxa up-regulation; as well as release of AIF and EndoG from the mitochondria. Finally, we show that 5-azacytidine-induced DNA DSB responses were mediated predominantly by ATR, and that doxorubicin, as well as bortezomib, synergistically enhanced 5-azacytidine-induced MM cell death. Taken together, these data provide the preclinical rationale for the clinical evaluation of 5-azacytidine, alone and in combination with doxorubicin and bortezomib, to improve patient outcome in MM.
在本研究中，我们调查了DNA甲基转移酶抑制剂5-氮杂胞苷对多发性骨髓瘤（MM）细胞的细胞毒性，并对细胞死亡的DNA损伤相关机制进行了表征。5-氮杂胞苷对传统治疗敏感和耐药的MM细胞系以及多药耐药的患者来源的MM细胞均显示出显著的细胞毒性，其半数抑制浓度（IC50）约为0.8 - 3微摩尔/升。相反，在这些剂量下，5-氮杂胞苷对外周血单核细胞或患者来源的骨髓基质细胞（BMSC）无细胞毒性。重要的是，5-氮杂胞苷克服了外源性白细胞介素-6（IL-6）、胰岛素样生长因子-I（IGF-I）或MM细胞与BMSC黏附所赋予的存活和生长优势。5-氮杂胞苷处理诱导了DNA双链断裂（DSB）反应，H2AX、Chk2和p53磷酸化以及MM细胞凋亡证明了这一点。5-氮杂胞苷诱导的凋亡既依赖于半胱天冬酶又不依赖于半胱天冬酶，伴有半胱天冬酶8和半胱天冬酶9的切割；Mcl-1的切割；Bax、Puma和Noxa的上调；以及线粒体中AIF和EndoG的释放。最后，我们表明5-氮杂胞苷诱导的DNA DSB反应主要由ATR介导，并且阿霉素以及硼替佐米协同增强了5-氮杂胞苷诱导的MM细胞死亡。综上所述，这些数据为5-氮杂胞苷单独以及与阿霉素和硼替佐米联合用于改善MM患者预后的临床评估提供了临床前依据。
