modulates s-mediated autophagy in human luminal breast cancer cell lines.

Autophagy is a conserved multi-step lysosomal process that is induced by diverse stimuli including cellular nutrient deficiency. () promotes cell survival and recently has been demonstrated to suppress autophagy. Herein, we examined regulation of -mediated autophagy in breast cancer cells and determined the underlying molecular mechanism. To investigate this process, autophagy of breast cancer cells was induced by Earle's balanced salt solution (EBSS). We observed discordant expression of mRNA and protein in the autophagic process induced by EBSS, suggesting may be regulated at a post-transcriptional level. By scanning several miRNAs potentially targeting , we observed that forced expression of significantly decreased the expression of and promoted autophagy, wherever down-regulation of increased expression and suppressed autophagy in breast cancer cells. was confirmed as a direct target of by reporter assay utilizing the 3'UTR of . , forced expression of promoted autophagy, colony formation, migration and invasion of breast cancer cell by down-regulation of expression. However, inhibited apoptosis of breast cancer cells independent of . Xenograft models confirmed the effect of on expression of and and that promoted breast cancer cell invasiveness. Therefore, our study demonstrates that modulates -mediated autophagy and promotes survival and migration in breast cancer cells and hence provides important new insights into the understanding of the development and progression of breast cancer.