Inhibition of the growth of non-small cell lung cancer by miRNA-1271

Non-small cell lung cancer (NSCLC) is a common lung cancer of high incidence. Since NSCLCs often grow rapidly, it is critical to elucidate the underlying mechanisms. Previous studies have shown that microRNAs (miRNAs) play critical roles in the carcinogenesis of NSCLC. Specifically, miR-1271 has been shown to downregulate in NSCLC cells. However, whether the downregulation of miR-1271 relates to carcinogenesis of NSCLC is unknown. Here, we analyzed the levels of miR-1271 and mTor in NSCLC specimens and studied their correlation. We performed bioinformatics analysis and luciferase-reporter assay to study the association of miR-1271 with mTor mRNA. We analyzed miR-1271 levels in NSCLC cells and studied their effects on mTor levels. The growth of miR-1271-modified NSCLC cells was evaluated in vitro in an MTT assay, and in vivo by bioluminescence. We detected significantly higher levels of mTor and significantly lower levels of miR-1271 in the NSCLC specimens, compared to the paired non-tumor lung tissues. We found that miR-1271 bound to the 3' UTR of mTor mRNA to prevent its translation. Overexpression of miR-1271 in NSCLC cells decreased mTor protein levels, whereas inhibition of miR-1271 increased mTor protein levels, without affecting mTor transcripts. Moreover, overexpression of miR-1271 suppressed the NSCLC growth in vitro and in vivo, while inhibition of miR-1271 significantly increased NSCLC growth. Together, these data suggest that in NSCLC, miR-1271 may inhibit the cancer cell growth through mTor suppression.