The miR-101/RUNX1 feedback regulatory loop modulates chemo-sensitivity and invasion in human lung cancer.

The deregulation of miR-101 has been implicated in multiple cancer types including lung cancer, but the exact role, mechanisms and how silencing of miR-101 remain elusive. Here we confirmed miR-101 downregulation in lung cancer cell lines and patient tissues. Restored miR-101 expression remarkably sensitized lung cancer cells to chemotherapy and inhibited invasion. Mechanistically, we indicated that miR-101 inversely correlated with RUNX1 expression, and identified RUNX1 as a novel target of miR-101. RUNX1 impaired the effects of miR-101 on chemotherapeutic sensitization and invasion inhibition. Moreover, RUNX1 knockdown resulted into increase of miR-101 expression and elevation of luciferase activity driven by miR-101 promoter in lung cancer cells, suggesting RUNX1 negatively transcriptionally regulated miR-101 expression via physically binding to miR-101 promoter. These findings support that miR-101 downregulation accelerates the progression of lung cancer via RUNX1 dependent manner and suggest that miR-101/RUNX1 feedback axis may have therapeutic value in treating refractory lung cancer.