Department of Cardiothoracic Surgery, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu, 215004, People's Republic of China.
J Exp Clin Cancer Res. 2019 Apr 8;38(1):149. doi: 10.1186/s13046-019-1161-8.
The cisplatin-resistance is still a main course for chemotherapy failure of lung cancer patients. Cisplatin-resistant cancer cells own higher malignance and exhibited increased metastatic ability, but the mechanism is not clear. In this study, we investigated the effects of Ataxia Telangiectasia Mutated (ATM) on lung cancer metastasis.
Cisplatin-resistant A549CisR and H157CisR cell line were generated by long-term treating parental A549 and H157 cells (A549P and H157P) with cisplatin. Cell growth, cell migration and cell invasion were determined. Gene expressions were determined by Western Blot and qPCR. Tumor metastasis was investigated using a xenograft mouse model.
The IC50 of the cisplatin-resistant cells (A549CisR and H157CisR cells) to cisplatin was 6-8 higher than parental cells. The A549CisR and H157CisR cells expressed lower level of E-cadherin and higher levels of N-cadherin, Vimentin and Snail compared to the parental A549P and H157P cells, and exhibited stronger capabilities of metastatic potential compared to the parental cells. The ATM expression was upregulated in A549CisR and H157CisR cells and cisplatin treatment also upregulated expression of ATM in parental cells, The inhibition of ATM by using specific ATM inhibitor CP466722 or knock-down ATM by siRNA suppressed Epithelial-to-Mesenchymal transition (EMT) and metastatic potential of A549CisR and H157CisR cells. These data suggest that ATM mediates the cisplatin-resistance in lung cancer cells. Expressions of JAK、 STAT 、PD-L1 and ATM were increased in A549CisR and H157CisR cells and could by induced by cisplatin in parental lung cancer cells. Interestedly, ATM upregulated PD-L1 expression via JAK/STAT pathway and inhibition of ATM decreased JAK/STAT3 signaling and decreased PD-L1 expression. The treatment of PD-L1 neutralizing Ab reduced EMT and cell invasion. Inhibition of JAK/STAT signaling by specific inhibitors suppressed ATM-induced PD-L1 expression, EMT and cell invasion. Importantly, inhibition of ATM suppressed EMT and tumor metastasis in cisplatin-resistant lung cancer cells in an orthotopic xenograft mouse model.
Our results show that ATM regulates PD-L1 expression through activation of JAK/STAT3 signaling in cisplatin-resistant cells. Overexpression of ATM contributes to cisplatin-resistance in lung cancer cells. Inhibition of ATM reversed EMT and inhibited cell invasion and tumor metastasis. Thus, ATM may be a potential target for the treatment of cisplatin-resistant lung cancer.
顺铂耐药仍然是肺癌患者化疗失败的主要原因。顺铂耐药癌细胞具有更高的恶性程度，并表现出更高的转移能力，但具体机制尚不清楚。在这项研究中，我们研究了共济失调毛细血管扩张突变（ATM）对肺癌转移的影响。
通过长期用顺铂处理亲本 A549 和 H157 细胞（A549P 和 H157P），生成顺铂耐药 A549CisR 和 H157CisR 细胞系。通过细胞生长、细胞迁移和细胞侵袭实验来检测细胞生长、细胞迁移和细胞侵袭能力。通过 Western Blot 和 qPCR 检测基因表达。利用异种移植小鼠模型研究肿瘤转移。
顺铂耐药细胞（A549CisR 和 H157CisR 细胞）对顺铂的 IC50 比亲本细胞高 6-8 倍。与亲本 A549P 和 H157P 细胞相比，A549CisR 和 H157CisR 细胞表达的 E-钙黏蛋白水平较低，而 N-钙黏蛋白、波形蛋白和 Snail 的水平较高，且与亲本细胞相比具有更强的转移潜能。A549CisR 和 H157CisR 细胞中 ATM 表达上调，顺铂处理也上调了亲本细胞中 ATM 的表达。使用特异性 ATM 抑制剂 CP466722 或 siRNA 敲低 ATM 可抑制 A549CisR 和 H157CisR 细胞的上皮-间充质转化（EMT）和转移潜能。这些数据表明，ATM 介导了肺癌细胞的顺铂耐药性。A549CisR 和 H157CisR 细胞中 JAK、STAT、PD-L1 和 ATM 的表达增加，并且亲本肺癌细胞中的顺铂可诱导其表达。有趣的是，ATM 通过 JAK/STAT 通路上调 PD-L1 表达，抑制 ATM 可降低 JAK/STAT3 信号，降低 PD-L1 表达。PD-L1 中和 Ab 的治疗可减少 EMT 和细胞侵袭。特异性抑制剂抑制 JAK/STAT 信号可抑制 ATM 诱导的 PD-L1 表达、EMT 和细胞侵袭。重要的是，在顺铂耐药性肺癌细胞的原位异种移植小鼠模型中，抑制 ATM 可抑制 EMT 和肿瘤转移。
我们的结果表明，ATM 通过激活 JAK/STAT3 信号通路调节顺铂耐药细胞中的 PD-L1 表达。ATM 的过表达有助于肺癌细胞对顺铂的耐药性。抑制 ATM 可逆转 EMT 并抑制细胞侵袭和肿瘤转移。因此，ATM 可能是治疗顺铂耐药性肺癌的潜在靶点。
