Knockdown of Myeloid Cell Leukemia-1 by MicroRNA-101 Increases Sensitivity of A549 Lung Cancer Cells to Etoposide

Studies have shown that myeloid cell leukemia-1 (Mcl-1) is the target gene for microRNA -101 (miRNA-101), and decreased levels of miRNA-101 are associated with elevated levels of Mcl-1 and lung cancer survival. The objective of the present study was to investigate the effect of miRNA-101 on the sensitivity of A549 lung cancer cells to etoposide. The study was conducted during 2018 and 2019 at Arak University of Medical Sciences, Arak, Iran. The effect of miRNA-101 on Mcl-1 expression was assessed using reverse transcription-quantitative polymerase chain reaction 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), and trypan blue exclusion assays were performed to determine the effect of treatments on cell survival and proliferation, respectively. The interaction between miRNA-101 and etoposide was evaluated using the combination index analysis of Chou-Talalay. Apoptosis was quantified using ELISA cell death assay. ANOVA and Bonferroni’s tests were used to determine statistical differences between the groups (P<0.05). GraphPad Prism software (version 6.01) was used for data analysis. The results showed that miRNA-101 clearly inhibited the expression of Mcl-1 and reduced the growth of A549 cells, relative to blank control and negative control miRNA (P<0.05). Transfection of miRNA-101 synergistically enhanced the sensitivity of the A549 cells to etoposide. Apoptosis assay data also showed that miRNA-101 triggered apoptosis and augmented the etoposide-mediated apoptosis. Up-regulation of miRNA-101 inhibited cell survival and proliferation, and sensitized A549 cells to etoposide by suppressing Mcl-1 expression. miRNA-101 replacement therapy can be considered as an effective therapeutic strategy in non-small cell lung cancer.