Wong Bing-Sang, Chiu Ling-Yen, Tu Dom-Gene, Sheu Gwo-Tarng, Chan Ting-Tat
Division of Neurosurgery, Antai Medical Care Corporation Antai Tian-Sheng Memorial Hospital, Pingtung County, Taiwan.
Department of Nuclear Medicine, Ditmanson Medical Foundation, Chia-Yi Christian Hospital, Chiayi City, Taiwan.
Cancer Manag Res. 2020 Mar 13;12:1913-1927. doi: 10.2147/CMAR.S228718. eCollection 2020.
Hypertension and cancer are frequently found comorbidity occurring in same individual. This study was intended to evaluate the anticancer effects of commonly used antihypertensive medications and chemotherapy on chemoresistant lung cancer cells.
Calcium channel blockers (CCBs), including Verapamil, Diltiazem, and Nifedipine, either alone or combined with docetaxel (DOC) or vincristine (VCR) were used to treat A549 lung adenocarcinoma chemoresistant sublines. Cell viability was determined by MTT assay, and colony formation assay was used to demonstrate the long-term effect of CCBs on proliferation of the sublines. Apoptosis was evaluated by Annexin V assay and autophagy intensity was quantitated from acidic vesicular organelle formation. Pan-caspase inhibitor, shATG5 interference and chloroquine were applied to study the roles of Verapamil on apoptosis and autophagy, with related proteins verified by Western blot analysis.
Results show that 10 μM of Verapamil and Diltiazem, but not Nifedipine, differentially induce autophagy in DOC-resistant or VCR-resistant A549 cells, respectively. When CCBs are combined with DOC or VCR to treat the sublines, 10 μM of Verapamil induces autophagy more significantly than Diltiazem and Nifedipine, respectively, in DOC-resistant (54.91±0.76, 18.03±0.69, 7.05±0.30) or VCR-resistant A549 (32.41±1.04, 21.51±0.63, 7.14±0.24) cells. Inhibition of apoptosis by pan-caspase inhibitor partly reduced cell death indicates association of caspase-dependent cell death but with persistence of autophagy. Inhibition of autophagy by interfering ATG5 expression reduced c-PARP level and apoptotic cells suggest a pro-death role of autophagy. Chloroquine treatment enhanced autophagosome accumulation and cell death but with reduced c-PARP level suggests that mechanism of caspase-independent cell death also contributes to Verapamil/chemotherapy-induced anticancer effects.
Verapamil combined with DOC or VCR induces chemoresistant lung cancer cells to death through autophagy burst and apoptosis more strongly than Diltiazem and Nifedipine. Administering Verapamil or Diltiazem individually with chemotherapy, but not Nifedipine, can be considered in lung cancer patients with hypertension.
高血压和癌症常合并发生于同一个体。本研究旨在评估常用降压药物与化疗对化疗耐药肺癌细胞的抗癌作用。
使用钙通道阻滞剂（CCB），包括维拉帕米、地尔硫䓬和硝苯地平，单独或与多西他赛（DOC）或长春新碱（VCR）联合使用，治疗A549肺腺癌化疗耐药亚系。通过MTT法测定细胞活力，集落形成试验用于证明CCB对亚系增殖的长期影响。通过膜联蛋白V试验评估细胞凋亡，并根据酸性囊泡细胞器的形成定量自噬强度。应用泛半胱天冬酶抑制剂、shATG5干扰和氯喹研究维拉帕米对细胞凋亡和自噬的作用，相关蛋白通过蛋白质印迹分析进行验证。
结果表明，10 μM的维拉帕米和地尔硫䓬分别在对DOC耐药或对VCR耐药的A549细胞中差异性诱导自噬，而硝苯地平则无此作用。当CCB与DOC或VCR联合用于治疗亚系时，在对DOC耐药（54.91±0.76、18.03±0.69、7.05±0.30）或对VCR耐药的A549（32.41±1.04、21.51±0.63、7.14±0.24）细胞中，10 μM的维拉帕米分别比地尔硫䓬和硝苯地平更显著地诱导自噬。泛半胱天冬酶抑制剂抑制细胞凋亡部分降低了细胞死亡，表明存在半胱天冬酶依赖性细胞死亡，但自噬持续存在。干扰ATG5表达抑制自噬降低了c-PARP水平和凋亡细胞，提示自噬具有促死亡作用。氯喹处理增强了自噬体积累和细胞死亡，但c-PARP水平降低，表明半胱天冬酶非依赖性细胞死亡机制也有助于维拉帕米/化疗诱导的抗癌作用。
维拉帕米与DOC或VCR联合使用比地尔硫䓬和硝苯地平更强烈地通过自噬爆发和细胞凋亡诱导化疗耐药肺癌细胞死亡。对于患有高血压的肺癌患者，可以考虑单独给予维拉帕米或地尔硫䓬联合化疗，但不包括硝苯地平。
