LncRNA MIR4435-2HG promotes proliferation, migration, invasion and EMT via targeting miR-22-3p/TMEM9B in breast cancer

Breast cancer, as the malignancy with the highest incidence rate and mortality rate in women, seriously threatens human life and health. Pieces of evidence have suggested that long non-coding RNAs (lncRNAs) possess important effects on regulating the occurrence and development of breast cancer. In addition, microRNA-22-3p (miR-22-3p) expression was down-regulated in breast cancer tissues and cell lines, and negatively associated with lncRNA MIR4435-2HG expression. Over-expression of miR-22-3p obviously inhibited the viability, proliferation, migration, invasion and EMT of breast cancer cell lines. Furthermore, Transmembrane protein 9 domain family member B (TMEM9B) was up-regulated in breast cancer tissues and cell lines and negatively associated with miR-22-3p expression. Finally, TMEM9B inhibition partially restored the effects of lncRNA MIR4435-2HG/miR-22-3p on the viability, proliferation, migration, invasion and EMT of breast cancer cell lines. LncRNA MIR4435-2HG potentially played a tumor-promoting role in the occurrence and development of breast cancer, which might be achieved by regulating the miR-22-3p/TMEM9B axis.