Tumor-suppressive microRNA-449a induces growth arrest and senescence by targeting E2F3 in human lung cancer cells

• miR-449a is significantly down-regulated in lung cancer tissues.
• miR-449a may predict the cancer recurrence and survival of lung cancer patients.
• miR-449a causes cell cycle arrest and senescence in lung cancer cells.
• E2F3 is a direct target of miR-449a.

MicroRNA-449a (miR-449a) was significantly downregulated in 156 lung cancer tissues (p < 0.001). We found that the low expression of miR-449a was highly correlated with cancer recurrence and survival of lung cancer patients. The transient introduction of miR-449a caused cell cycle arrest and cell senescence in A549 and 95D cells. Further studies revealed that E2F3 was a direct target of miR-449a in lung cancer cells. miR-449a also suppressed tumor formation in vivo in nude mice. These results suggest that miR-449a plays an important role in lung cancer tumorigenesis and that miR-449a might predict cancer recurrence and survival of lung cancer patients.