Laboratory of Medicinal and Biochemical Analysis, Faculty of Pharmaceutical Sciences, Hiroshima International University, Kure, Hiroshima 737-0112, Japan; Department of Medical Pharmaceutics, Kobe Pharmaceutical University, Kobe 658-8558, Japan.
Laboratory of Medicinal and Biochemical Analysis, Faculty of Pharmaceutical Sciences, Hiroshima International University, Kure, Hiroshima 737-0112, Japan.
Life Sci. 2015 Mar 1;124:31-40. doi: 10.1016/j.lfs.2015.01.011. Epub 2015 Jan 24.
Cisplatin (CDDP) is a platinum-based drug that is widely used in cancer chemotherapy, but the development of resistance in tumor cells is a major weakness of these treatments. Several mechanisms have been proposed to explain cisplatin resistance, and disruption of certain cellular pathways could modulate drug sensitivity to cisplatin. A lower level of cross-resistance to cisplatin leads to better outcomes in clinical use.
Cross-resistance was assessed using cisplatin resistant lung cancer cell line A549/CDDP. Cell cycle analysis was used to examine the effect of cisplatin on cell signaling pathways regulating G2/M transition in cisplatin resistant cells.
A549/CDDP cells exhibited cross-resistance to carboplatin, but not oxaliplatin, which is often found in platinum analogues. Flow cytometry showed that nocodazole treatment caused a G2/M block in both A549/CDDP cells and cisplatin susceptible cells. However, A549/CDDP cells escaped the G2/M block following exposure to cisplatin. Activation of the Cdc2/CyclinB complex is required for transition from G2 to M phase, and the inactive form of phosphorylated Cdc2 is activated by Cdc25C dephosphorylation of Tyr15. In the cisplatin-treated susceptible cells, the levels of phosphorylated Cdc2 and Cdc25C were markedly decreased, leading to a loss of Cdc2 activity and G2/M arrest. In A549/CDDP cells, however, Cdc2 activity was supported by the expression of Cdc2 and Cdc25C after the addition of cisplatin, which resulted in G2/M progression.
The resistance phenotype of G2/M progression has been correlated with dysregulation of Cdc2 in a human lung cancer cell line selected for cisplatin.
顺铂（CDDP）是一种广泛应用于癌症化疗的铂类药物，但肿瘤细胞耐药性的发展是这些治疗方法的一个主要弱点。已经提出了几种机制来解释顺铂耐药性，并且破坏某些细胞途径可以调节顺铂的药物敏感性。较低水平的交叉耐药性导致顺铂在临床应用中获得更好的效果。
使用顺铂耐药性肺癌细胞系 A549/CDDP 评估交叉耐药性。细胞周期分析用于研究顺铂对调节顺铂耐药细胞中 G2/M 转换的细胞信号通路的影响。
A549/CDDP 细胞对卡铂表现出交叉耐药性，但对奥沙利铂（铂类似物中常发现的）没有交叉耐药性。流式细胞术显示，在 A549/CDDP 细胞和对顺铂敏感的细胞中，诺考达唑处理导致 G2/M 阻滞。然而，A549/CDDP 细胞在暴露于顺铂后逃脱了 G2/M 阻滞。Cdc2/CyclinB 复合物的激活对于从 G2 到 M 期的过渡是必需的，并且磷酸化 Cdc2 的无活性形式通过 Cdc25C 对 Tyr15 的去磷酸化而被激活。在顺铂处理的敏感细胞中，磷酸化 Cdc2 和 Cdc25C 的水平明显降低，导致 Cdc2 活性丧失和 G2/M 阻滞。然而，在 A549/CDDP 细胞中，Cdc2 活性在添加顺铂后通过 Cdc2 和 Cdc25C 的表达得到支持，导致 G2/M 进展。
在选择用于顺铂的人类肺癌细胞系中，G2/M 进展的耐药表型与 Cdc2 的失调相关。
