LncRNA MALAT1 Promotes Lung Cancer Proliferation and Gefitinib Resistance by Acting as a miR-200a Sponge

Lung cancer is a major public health problem, as the second causes of cancer related death worldwide, with relatively low survival rates, and accessible drug resistance. Long non-coding RNAs (LncRNAs) have been identified as activator in lung cancer with elusive mechanisms. We aimed to detect the regulation of LncRNA MALAT1 in the proliferation and gefitinib resistance in lung cancer cells.MALAT1 in A549 and HCC 1299 human lung adenocarcinoma cell lines was silenced by shRNA or overexpressed using plasmid, and the cell viability and cell proliferation were evaluated by MTT assay and soft agar colony formation assay. RNA levels were detected by RT-PCR, and the protein expression was measured by western blot. The binding between MALAT1 and miR-200a was validated by luciferase reporter assays using pSi-Chech 2 vectors.The cell viability and proliferation of A549 cells transfected with MALAT1 shRNA were significantly lower than the control. The MALAT1 expression in gefitinib resistant A549 cells was upregulated. miR-200a significantly inhibited the fluorescence of pSi-Check 2 vector with MALAT1 gene, suggesting the direct binding between MALAT1 and miR-200a. In addition, LncRNA MALAT1 promotes ZEB1 expression in A549 cells.Our study showed that MALAT1 promoted the proliferation and gefitinib resistance of lung cancer cells by sponging miR-200a, which regulates expression of ZEB1 in the A549 cells. This MALAT1/miR-200a axis could serve as new therapeutic target for lung cancer treatment.