miR-335 inhibited cell proliferation of lung cancer cells by target Tra2β.

Accumulating evidence has suggested that the dysregulation of miRNA is an important factor in the pathogenesis of lung cancer. Here, we demonstrate that miR-335 expression is reduced in non-small cell lung cancer (NSCLC) tumors relative to non-cancerous adjacent tissues, while the expression of Tra2β is increased. In addition, clinical data revealed that the increased Tra2β and decreased miR-335 expression observed in NSCLC cells was associated with poor patient survival rates. In vitro experimentation showed that the overexpression of miR-335 inhibited the growth, invasion and migration capabilities of A459 lung cancer cells, by targeting Tra2β. In contrast, inhibition of miR-335 or overexpression of the Tra2β target gene stimulated the growth, invasion and migratory capabilities of A459 lung cancer cells in vitro. Furthermore, overexpression of miR-335 or inhibition of Tra2β decreased the phosphorylation of Rb-S780 and Rb-AKT. Overall, these findings suggest that the downregulation of miR-335 in A459 lung cancer cells promoted cell proliferation through upregulation of Tra2β, mediated via activation of the AKT/mTOR signaling pathway, and suggest that miR-335 may have potential as a novel therapeutic target for NSCLC.