Zhao Xiang, He Rong, Liu Yu, Wu Yongkai, Kang Leitao
Department of Thoracic Surgery, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & Institute, 44 Xiaoheyan Road, Dadong Region, Shenyang, 110042, Liaoning, China.
Basic Medical Department, Central South University, Changsha, 410000, China.
Mol Cell Biochem. 2017 Jul;431(1-2):21-27. doi: 10.1007/s11010-017-2970-8. Epub 2017 Feb 16.
Cisplatin and its analogues are widely used as anti-tumor drugs in lung cancer but many cisplatin-resistant lung cancer cases have been identified in recent years. Single-stranded DNA-binding protein 1 (SSDBP1) can effectively induce H69 cell resistance to cisplatin in our previous identification; thus, it is necessary to explore the mechanism underlying the effects of SSDBP1-induced resistance to cisplatin. First, SSDBP1-overexpressed or silent cell line was constructed and used to analyze the effects of SSDBP1 on chemoresistance of lung cancer cells to cisplatin. SSDBP1 expression was assayed by real-time PCR and Western blot. Next, the effects of SSDBP1 on cisplatin sensitivity, proliferation, and apoptosis of lung cancer cell lines were assayed by MTT and flow cytometry, respectively; ABC transporters, apoptosis-related genes, and cell cycle-related genes by real-time PCR, and DNA wound repair by comet assay. Low expression of SSDBP1 was observed in H69 cells, while increased expression in cisplatin-resistant H69 cells. Upregulated expression of SSDBP1 in H69AR cells was identified to promote proliferation and cisplatin resistance and inhibit apoptosis, while downregulation of SSDBP1 to inhibit cisplatin resistance and proliferation and promoted apoptosis. Moreover, SSDBP1 promoted the expression of P2gp, MRP1, Cyclin D1, and CDK4 and inhibited the expression of caspase 3 and caspase 9. Furthermore, SSDBP1 promoted the DNA wound repair. These results indicated that SSDBP1 may induce cell chemoresistance of cisplatin through promoting DNA repair, resistance-related gene expression, cell proliferation, and inhibiting apoptosis.
顺铂及其类似物作为抗肿瘤药物在肺癌治疗中被广泛应用，但近年来已发现许多顺铂耐药的肺癌病例。在我们之前的研究中，单链DNA结合蛋白1（SSDBP1）能有效诱导H69细胞对顺铂产生耐药性；因此，有必要探究SSDBP1诱导顺铂耐药的作用机制。首先，构建了SSDBP1过表达或沉默的细胞系，并用于分析SSDBP1对肺癌细胞顺铂化疗耐药性的影响。通过实时PCR和蛋白质免疫印迹法检测SSDBP1的表达。接下来，分别通过MTT法和流式细胞术检测SSDBP1对肺癌细胞系顺铂敏感性、增殖和凋亡的影响；通过实时PCR检测ABC转运蛋白、凋亡相关基因和细胞周期相关基因，通过彗星试验检测DNA损伤修复情况。在H69细胞中观察到SSDBP1低表达，而在顺铂耐药的H69细胞中表达增加。在H69AR细胞中，上调SSDBP1的表达可促进增殖和顺铂耐药性，并抑制凋亡，而下调SSDBP1则可抑制顺铂耐药性和增殖，并促进凋亡。此外，SSDBP1促进P2gp、MRP1、细胞周期蛋白D1和细胞周期蛋白依赖性激酶4的表达，并抑制半胱天冬酶3和半胱天冬酶9的表达。此外，SSDBP1促进DNA损伤修复。这些结果表明，SSDBP1可能通过促进DNA修复、耐药相关基因表达、细胞增殖和抑制凋亡来诱导细胞对顺铂的化疗耐药性。
