Wang Cheng-Yi, Chao Ting-Ting, Chang Fang-Yu, Chen Yen-Lin, Tsai Yi-Ting, Lin Hen-I, Huang Yuh-Chin T, Shiau Chung-Wai, Yu Chong-Jen, Chen Kuen-Feng
Department of Internal Medicine, Cardinal Tien Hospital, School of Medicine, Fu Jen Catholic University, New Taipei City 23148, Taiwan; Medical Research Center, Cardinal Tien Hospital, School of Medicine, Fu Jen Catholic University, New Taipei City 23148, Taiwan; Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan.
Medical Research Center, Cardinal Tien Hospital, School of Medicine, Fu Jen Catholic University, New Taipei City 23148, Taiwan.
Lung Cancer. 2014 Aug;85(2):152-60. doi: 10.1016/j.lungcan.2014.05.024. Epub 2014 Jun 5.
Epidermal growth factor receptor (EGFR) inhibitors show favorable clinical response in some patients with non-small cell lung cancer (NSCLC) who have no EGFR mutation, indicating alternative mechanisms for their tumoricidal effects. We previously showed erlotinib, a selective EGFR antagonist, inhibited the growth of sensitive hepatocellular carcinoma cells by inhibiting the cancerous inhibitor of protein phosphatase 2A (CIP2A) pathway. The aim of this study was to determine if erlotinib can also inhibit the growth of NSCLC cells by inactivating the CIP2A-dependent signaling pathway.
Four NSCLC cell lines (H358 H441 H460 and A549) were treated with erlotinib to determine their sensitivity to erlotinib-induced cell death and apoptosis. Expression of CIP2A and the downstream AKT were analyzed. The effects of CIP2A on erlotinib-induced apoptosis were confirmed by overexpression of CIP2A and knockdown of CIP2A gene expression in the sensitive cells and resistant cells, respectively. In vivo efficacy of erlotinib against H358 xenograft tumor was also determined in nude mice.
Erlotinib induced significant cell death and apoptosis in H358 and H441 cells, as evidenced by increased caspase 3 activity and cleavage of pro-caspase 9 and PARP, but not in H460 or A549 cells. The apoptotic effect of erlotinib in the sensitive H358 cells was associated with downregulation of CIP2A, increase in PP2A activity and decrease in AKT phosphorylation. Overexpression of CIP2A and AKT protected the sensitive H358 cells from erlotinib-induced apoptosis. Knockdown of CIP2A gene expression by siRNA enhanced the erlotinib-induced apoptotic in the resistant H460 cells that resembled the sensitive H358 cells. Erlotinib also inhibited the growth of H358 tumors in nude mice.
The CIP2A-dependent pathway mediates the tumoricidal effects of erlotinib on NSCLC cells without EGFR mutations in vitro and in vivo. CIP2A may be a novel molecular target against NSCLC for future drug development.
表皮生长因子受体（EGFR）抑制剂在一些无EGFR突变的非小细胞肺癌（NSCLC）患者中显示出良好的临床反应，这表明其杀肿瘤作用存在其他机制。我们之前发现，选择性EGFR拮抗剂厄洛替尼通过抑制蛋白磷酸酶2A的癌性抑制剂（CIP2A）途径来抑制敏感肝癌细胞的生长。本研究的目的是确定厄洛替尼是否也能通过使依赖CIP2A的信号通路失活来抑制NSCLC细胞的生长。
用厄洛替尼处理四种NSCLC细胞系（H358、H441、H460和A549），以确定它们对厄洛替尼诱导的细胞死亡和凋亡的敏感性。分析CIP2A和下游AKT的表达。通过分别在敏感细胞和耐药细胞中过表达CIP2A和敲低CIP2A基因表达，证实CIP2A对厄洛替尼诱导的凋亡的影响。还在裸鼠中确定了厄洛替尼对H358异种移植瘤的体内疗效。
厄洛替尼诱导H358和H441细胞发生显著的细胞死亡和凋亡，这通过半胱天冬酶3活性增加以及前半胱天冬酶9和PARP的裂解得到证实，但在H460或A549细胞中未观察到。厄洛替尼在敏感的H358细胞中的凋亡作用与CIP2A的下调、PP2A活性的增加以及AKT磷酸化的减少有关。CIP2A和AKT的过表达保护敏感的H358细胞免受厄洛替尼诱导的凋亡。用小干扰RNA敲低CIP2A基因表达增强了厄洛替尼在耐药的H460细胞中诱导的凋亡，这些细胞类似于敏感的H358细胞。厄洛替尼还抑制了裸鼠中H358肿瘤的生长。
依赖CIP2A的途径在体外和体内介导了厄洛替尼对无EGFR突变的NSCLC细胞的杀肿瘤作用。CIP2A可能是未来针对NSCLC药物开发的一个新的分子靶点。
