Background and objective: Cisplatin-resistance in Lung cancer cells is widespread in the clinical treatment, seriously affecting the effects of the treatment of lung cancer. Therefore, the research of mechanisms of cisplain-resistance has significant meaning for developing new chemotherapeutic drug and solving the cisplain-resistance in clinic treatment. IKBKB is one of the most important catalytic subunits of IKK complexes. It plays an important regulatory role in activation of NF-κB. The aim of this study is to investigate the differential expression of IKBKB gene in human lung adenocarcinoma cells line A549 and the cisplatin-resistant variant A549/DDP and the mechanisms of cisplain-resistance induced by IKBKB gene.
Methods: MTT assay was employed to determine the sensitivity of A549 and A549/DDP cells line to cisplatin and the effect of IKBKB gene on A549 cell lines' sensitivity to cisplatin. The mRNA level of IKBKB was determined by real-time PCR. Dual luciferase reporter gene experiment was employed to determine the activity of the NF-κB. Apoptosis rate of lung adenocarcinoma cells was determined by flow cytometry.
Results: Apoptosis rate and IC50 were significantly different in A549 and A549/DDP cells, the expression of mRNA level of IKBKB gene in A549/DDP was significantly higher than that in A549. Compared with control group, IKBKB gene was able to reduce the cisplain sensitivity of A549 cells. After A549 was transfected with pcDNA3.1/IKBKB plasmid, mRNA level of IKBKB was significantly increased, the sensitivity of cisplain was decreased, the IC50 was increased 2.85 fold, the apoptosis rate was decreased 59%, the activity of NF-κB has been greatly increased.
Conclusions: IKBKB inhibits cisplatin-induced apoptosis via the activation of NF-κB pathway. It will be helpful in the development of new anticancer drug and solving the challenge of cisplatin-resistance.
背景与目的 肺癌顺铂耐药在临床治疗中广泛存在，严重影响了肺癌患者的治疗效果，因此研究肺癌耐药机制对新药的研发和解决临床肿瘤耐药有十分重要的意义。IKBKB是组成IKK复合物重要的催化亚基之一，其对核转录因子NF-κB的激活起到重要调控作用。本研究旨在探讨IKBKB基因在肺腺癌顺铂耐药细胞株（A549/DDP）与其亲本肺腺癌A549细胞株中的表差异及其调控肺腺癌顺铂耐药的机制。方法 应用MTT法检测A549和A549/DDP细胞株顺铂敏感性及IKBKB基因对A549细胞株顺铂耐药性的影响。Real-time PCR检测肿瘤细胞中IKBKB基因mRNA变化，流式细胞学检测肿瘤细胞凋亡率，双荧光素酶报告基因实验检测NF-κB的活性。结果 A549细胞与A549/DDP细胞在IC50和凋亡率方面均有统计学差异，IKBKB基因在A549/DDP细胞株中mRNA表达水平明显高于A549。与对照组比较，pcDNA3.1/IKBKB转染A549细胞后，IKBKB基因在mRNA水平明显升高，A549细胞顺铂耐药性明显增加，IC50增加2.85倍，凋亡率减少59%，NF-κB的活性明显升高。结论 IKBKB基因通过激活NF-κB信号通路抑制细胞凋亡，从而导致细胞耐药性增加，这一研究结果对新抗肿瘤药物的研发和解决肿瘤耐药难题有重要意义。