Down-Regulation of ZEB1 by miR-199a-3p Overexpression Restrains Tumor Stem-Like Properties and Mitochondrial Function of Non-Small Cell Lung Cancer.

Objective: MicroRNA-199a-3p (miR-199a-3p or miR-199b-3p) targeting of 3'-UTR of ZEB1 was characterized as an important way to inhibit invasion and metastases in non-small cell lung cancer (NSCLC), one of the most common cancers around the world. Here we aimed to investigate the tumor-suppressive role of miR-199a-3p targeted ZEB1.

Materials And Methods: A549 cells were transfected with ZEB1 and/or miR-199a-3p. Then, tumor growth was investigated in xenograft mice. Stem-like property, proliferation and mitochondria injury were further validated in vitro.

Results: Overexpression of miR-199a-3p with premiRNAs significantly reduced tumor growth inhibited CD44 and Ki67 and increased Caspase-3 in A549 xenograft mice. Sphere formation and protein expression of stem-like markers showed that miR-199a-3p inhibited stemness of A549 cell. miR-199a-3p reduced proliferation of A549 cells, as showed with EdU staining and reduced expression of Ki67. Transfection of miR-199a-3p also promoted apoptosis, as indicated with increased apoptotic cells with flow cytometry, and increased cleaved Caspase-3/Caspase3 and Bcl-2/Bax. Apoptosis was further validated to be induced with mitochondria dysfunction, which indicated with JC-1 labeled loss of mitochondrial membrane potential, reduced activity of SOD, and increased MDA and LDH. All these effects were inverted with overexpression of ZEB1.

Conclusion: Altogether, the findings suggested that the up-regulation of miR-199a-3p significantly inhibited NSCLC growth in vivo, and reduced A549 cell proliferation and promoted mitochondrial-mediated apoptosis, through down-regulation of ZEB1. The findings supported ZEB1 down-expression with miR-199a-3p as a novel therapeutic target for NSCLC treatment.