1] INSERM, U848, Villejuif, France [2] Institut Gustave Roussy, Villejuif, France [3] Hôpital Robert Debré, AP-HP, Paris, France.
Oncogene. 2013 Sep 12;32(37):4331-42. doi: 10.1038/onc.2012.469. Epub 2012 Oct 22.
The term myelodysplastic syndrome (MDS) identifies a heterogeneous group of clonal disorders originating from bone marrow stem cells that often progress to acute myeloid leukemia (AML). The reference treatments for MDS include the DNA methyltransferase inhibitors azacytidine and decitabine. Recently, the epidermal growth factor receptor (EGFR) inhibitor erlotinib has been shown to exert antileukemic activity in vitro and in vivo, independent of the EGFR. Thanks to this feature, erlotinib is currently being tested as an antileukemic drug in clinical trials. Here, we report that azacytidine and erlotinib mediate synergistic antineoplastic effects in several primary or secondary (post-MDS) AML cell lines. The combination of azacytidine and erlotinib blocked cell-cycle progression and induced caspase-dependent apoptosis more consistently than either of the two agents alone. These effects were not a consequence of cellular differentiation and could be discriminated from each other, as the former depended on caspases whereas the latter did not. The synergy between azacitidine and erlotinib, which involved the proteasomal degradation of the anti-apoptotic Bcl-2 family members MCL-1 and BCL2L10 and the upregulation of their pro-apoptotic counterpart PUMA, was abolished when azacytidine was replaced by decitabine but persisted when erlotinib was substituted with gefitinib, another EGFR inhibitor. Of note, the intracellular accumulation of azacytidine was exacerbated by both erlotinib and gefitinib, pointing to a pharmacokinetic mechanism of synergy. In approximately half of the cases studied, marrow and circulating blasts from MDS and AML patients, respectively, exhibited hyperadditive cytotoxic responses to the combination of azacytidine and erlotinib. These results strongly suggest that the combination of azacytidine and erlotinib may exert clinically relevant antileukemic effects.
骨髓增生异常综合征（MDS）是一组异质性克隆性疾病，起源于骨髓干细胞，常进展为急性髓系白血病（AML）。MDS 的标准治疗包括 DNA 甲基转移酶抑制剂阿扎胞苷和地西他滨。最近，表皮生长因子受体（EGFR）抑制剂厄洛替尼已被证明在体外和体内具有抗白血病活性，而与 EGFR 无关。由于这一特点，厄洛替尼目前正在临床试验中作为一种抗白血病药物进行测试。在这里，我们报告阿扎胞苷和厄洛替尼在几种原发性或继发性（MDS 后）AML 细胞系中具有协同抗肿瘤作用。阿扎胞苷和厄洛替尼联合阻断细胞周期进展，并诱导 caspase 依赖性细胞凋亡的作用比单独使用两种药物中的任何一种都更一致。这些作用不是细胞分化的结果，彼此之间可以区分开来，因为前者依赖于半胱天冬酶，而后者则不依赖于半胱天冬酶。阿扎胞苷和厄洛替尼之间的协同作用涉及抗凋亡 Bcl-2 家族成员 MCL-1 和 BCL2L10 的蛋白酶体降解，以及其促凋亡对应物 PUMA 的上调，当用地西他滨替代阿扎胞苷时，这种协同作用被消除，但当用另一种 EGFR 抑制剂吉非替尼替代厄洛替尼时，这种协同作用仍然存在。值得注意的是，厄洛替尼和吉非替尼均可加剧阿扎胞苷的细胞内积累，这表明存在协同的药代动力学机制。在所研究的大约一半病例中，MDS 和 AML 患者的骨髓和循环中的原始细胞对阿扎胞苷和厄洛替尼的联合治疗表现出超相加细胞毒性反应。这些结果强烈表明，阿扎胞苷和厄洛替尼的联合治疗可能具有临床相关的抗白血病作用。
