MiR-449c targets c-Myc and inhibits NSCLC cell progression

• miR-449c is downregulated in NSCLC specimens and cells compared to normal lung tissues.
• miR-449c inversely correlates with c-Myc expression in NSCLC.
• miR-449c inhibits proliferation and promotes apoptosis of NSCLC cells.
• miR-449c directly represses c-Myc expression in NSCLC cells.
• miR-449c inhibits tumor growth of NSCLC in vivo.

MicroRNAs (miRNA) play an important role in tumorigenesis, proliferation, and differentiation. Altered miRNA expression in cancer indicates that miRNAs can function as tumor suppressors or oncogenes. MiR-449c downregulation in non-small cell lung cancer (NSCLC) compared with normal lung tissues was investigated in this study. NSCLC cell proliferation and invasion assays indicate that transfection of miR-449c expression plasmid inhibits the proliferation and invasion ability of NCI-H23 and NCI-H838 cells. In addition, miR-449c overexpression could suppress tumor growth in vivo. Morever, c-Myc was identified as a direct target gene of miR-449c. These findings clearly suggest that miR-449c downregulation and c-Myc amplification may be involved in the development of NSCLC.