罗地替尼增强阿糖胞苷（Ara-C）诱导的急性髓系白血病细胞死亡。

BACKGROUND: Acute myeloid leukemia (AML) is a heterogeneous disease that frequently relapses after standard chemotherapy. Therefore, there is a need for the development of novel chemotherapeutic agents that could treat AML effectively. Radotinib, an oral BCR-ABL tyrosine kinase inhibitor, was developed as a drug for the treatment of chronic myeloid leukemia. Previously, we reported that radotinib exerts increased cytotoxic effects towards AML cells. However, little is known about the effects of combining radotinib with Ara-C, a conventional chemotherapeutic agent for AML, with respect to cell death in AML cells. Therefore, we investigated combination effects of radotinib and Ara-C on AML in this study. METHODS: Synergistic anti-cancer effects of radotinib and Ara-C in AML cells including HL60, HEL92.1.7, THP-1 and bone marrow cells from AML patients have been examined. Diverse cell biological assays such as cell viability assay, Annexin V-positive cells, caspase-3 activity, cell cycle distribution, and related signaling pathway have been performed. RESULTS: The combination of radotinib and Ara-C was found to induce AML cell apoptosis, which involved the mitochondrial pathway. In brief, combined radotinib and Ara-C significantly induced Annexin V-positive cells, cytosolic cytochrome C, and the pro-apoptotic protein Bax in AML cells including HL60, HEL92.1.7, and THP-1. In addition, mitochondrial membrane potential and Bcl-xl protein were markedly decreased by radotinib and Ara-C. Moreover, this combination induced caspase-3 activity. Cleaved caspase-3, 7, and 9 levels were also increased by combined radotinib and Ara-C. Additionally, radotinib and Ara-C co-treatment induced G/G arrest via the induction of CDKIs such as p21 and p27 and the inhibition of CDK2 and cyclin E. Thus, radotinib/Ara-C induces mitochondrial-dependent apoptosis and G/G arrest via the regulation of the CDKI-CDK-cyclin cascade in AML cells. In addition, our results showed that combined treatment with radotinib and Ara-C inhibits AML cell growth, including tumor volumes and weights in vivo. Also, the combination of radotinib and Ara-C can sensitize cells to chemotherapeutic agents such as daunorubicin or idarubicin in AML cells. CONCLUSIONS: Therefore, our results can be concluded that radotinib in combination with Ara-C possesses a strong anti-AML activity.

背景：急性髓细胞白血病（AML）是一种异质性疾病，在标准化疗后常复发。因此，需要开发新的化疗药物来有效治疗 AML。罗地替尼是一种口服 BCR-ABL 酪氨酸激酶抑制剂，被开发用于治疗慢性髓细胞白血病。先前，我们报道罗地替尼对 AML 细胞具有增强的细胞毒性作用。然而，对于罗地替尼与阿糖胞苷（AML 的常规化疗药物）联合使用对 AML 细胞死亡的影响知之甚少。因此，我们在这项研究中研究了罗地替尼和阿糖胞苷联合治疗 AML 的效果。

方法：研究了罗地替尼和阿糖胞苷在包括 HL60、HEL92.1.7、THP-1 和 AML 患者骨髓细胞在内的 AML 细胞中的协同抗癌作用。进行了多种细胞生物学测定，如细胞活力测定、Annexin V 阳性细胞、半胱天冬酶-3 活性、细胞周期分布和相关信号通路。

结果：发现罗地替尼和阿糖胞苷联合使用可诱导 AML 细胞凋亡，涉及线粒体途径。简而言之，联合使用罗地替尼和阿糖胞苷可显著诱导 Annexin V 阳性细胞、细胞质细胞色素 C 和促凋亡蛋白 Bax 在包括 HL60、HEL92.1.7 和 THP-1 在内的 AML 细胞中表达。此外，罗地替尼和阿糖胞苷显著降低线粒体膜电位和 Bcl-xl 蛋白。此外，这种联合作用诱导了半胱天冬酶-3 的活性。Cleaved caspase-3、7 和 9 水平也因罗地替尼和阿糖胞苷的联合使用而升高。此外，罗地替尼和阿糖胞苷共同处理通过诱导 CDKIs（如 p21 和 p27）和抑制 CDK2 和细胞周期蛋白 E 诱导 G1/G0 期阻滞。因此，罗地替尼/阿糖胞苷通过调节 AML 细胞中 CDKIs-CDK-cyclin 级联反应诱导线粒体依赖性凋亡和 G1/G0 期阻滞。此外，我们的结果表明，联合使用罗地替尼和阿糖胞苷可抑制体内 AML 细胞的生长，包括肿瘤体积和重量。此外，罗地替尼和阿糖胞苷的联合使用可以使 AML 细胞对柔红霉素或伊达比星等化疗药物敏感。

结论：因此，我们的结果可以得出结论，罗地替尼联合阿糖胞苷具有很强的抗 AML 活性。