MicroRNA-206 inhibits cell growth in malignant pleural mesothelioma

Abstract

Objective To investigate the suppressive effect of miR-206 on malignant pleural mesothelioma (MPM) cell lines and mechanism. Methods A mimic of miR-206 was introduced into MPM cell lines H513, H2052 and H2373 to overexpress this microRNA. (1) miRNA-induced changes in cell growth were evaluated by crystal violet staining. (2) Genes associated with cell cycle homeostasis and apoptosis were examined by real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR). (3) By gene knockdown experiment and RT-qPCR, the potential mechanism of the suppressive effect was analyzed. Results (1) Cellular growth in H513, H2052, H2373 were significantly inhibited after overexpression of miR-206 at day 3 (570 nm: 0.406±0.196 vs. 0.682±0.042, 0.192±0.181 vs. 0.587±0.264, 0.178±0.056 vs. 0.794±0.276, P<0.05). (2) Gene expression levels of B cell lymphoma/leukemia-2 associated X protein (bax), p53, and p27 were all significantly increased (average fold change: 1.489±0.355, 1.298±0.336, 1.746±0.389, P<0.05) in miR-206-transfected MPM cells. Coordinately, gene expression levels of proliferating cell nuclear antigen (PCNA) and B cell lymphoma/leukemia-2 (bcl-2) were significantly decreased (average fold change: 1.489±0.355, 1.298±0.336, P<0.05). Significant attenuation of histone deacetylase (HDAC) activity was observed (average fold change: 0.984±0.271 vs. 0.442±0.149 vs. 0.520±0.193, P<0.05), and suppression of HDAC activity mediated by negative regulation of HDAC4 and 6 genes is an effect unique to miR-206. (3) All MPM cell lines tested with either HDAC4 or HDAC6 knockdown exhibited significant growth arrest by crystal violet staining (570 nm: 0.971±0.205 vs. 0.427±0.152 vs. 0.520±0.191, P<0.05), which was consist with suppression of HDAC, indicating HDAC4 and HDAC6 were significant effector molecules for the suppressive effect. Conclusion Overexpression of miR-206 acts as a tumor suppressor in MPM. Key words: Malignant pleural mesothelioma; MicroRNA; Apoptosis; Growth arrest; Histone deacetylase