Objective   To investigate the effects of miR-200a on the proliferation of lung cancer cells and to identify its direct target genes.

  Methods   Real-time PCR was performed to analyze the miR-200a expression in 15 paired clinical specimens of non-small cell lung cancer and adjacent noncancerous tissues, human lung cancer cell lines (A549, NCI-H520, and SK-MES-1), and one human normal lung bronchial epithelial cell line (16HBE). The effects of miR-200a on the proliferation of A549 lung cancer cells were detected through CCK-8 method. The candidate target genes of miR-200a were identified by bioinformatics screening and then verified by dual luciferase reporter gene assay, real-time PCR, and Western blot. The effects of YAP1 downregulation on the proliferation of A549 lung cancer cell line were also observed through CCK-8 method.

  Results   The miR-200a expression in non-small cell lung cancer tissues and lung cancer cell lines was significantly decreased (P < 0.01). The upregulation of miR-200a expression could significantly inhibit the proliferation of A549 lung cancer cells (P < 0.01). Dual luciferase reporter gene indicated that miR-200a could directly affect the 3′-untranslated region of the YAP1 gene to inhibit luciferase activity (P < 0.01). Real-time PCR and Western blot revealed that the upregulation of miR-200a expression could significantly reduce the mRNA and protein expression levels of YAP1 in A549 lung cancer cells (P < 0.01). CCK-8 method indicated that the downregulation of YAP1 could significantly prevent the proliferation of A549 lung cancer cells (P < 0.01).

  Conclusion   MiR-200a inhibits the proliferation of lung cancer cells by targeting YAP1. Thus, miR-200a elicits tumor suppression effects.