hsa-mir-181a and hsa-mir-181b function as tumor suppressors in human glioma cells.

MicroRNAs (miRNAs) are small noncoding RNA molecules that regulate protein expression by cleaving or repressing the translation of target mRNAs. In mammal animals, their function mainly represses the target mRNAs transcripts via imperfectly complementary to the 3' UTR of target mRNAs. Several miRNAs have been recently reported to be involved in modulation of glioma development, especially some up-regulated miRNA, such as hsa-miR-21 and hsa-miR-221. However, here we reported that the down-regulated hsa-miR-181a and hsa-miR-181b of hsa-miR-181 family were also involved in oncogenesis of glioma. Our studies showed that hsa-miR-181a and hsa-miR-181b functioned as tumor suppressors which triggered growth inhibition, induced apoptosis and inhibited invasion in glioma cells. Furthermore, the tumor-suppressive effect of hsa-miR-181b in glioma cells was more apparent than the effect of hsa-miR-181a. These findings suggest aberrantly down-regulated hsa-miR-181a and hsa-miR-181b may be critical factors that contribute to malignant appearance in human gliomas.