[Expression and Significance of IKBKB in Pulmonary Adenocarcinoma A549 Cells and Its Cisplatin-resistant Variant A549/DDP]

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.