OBJECTIVE

Triple-negative breast cancers (TNBC) are a subtype of breast cancer lacking of estrogen receptor (ER), progesterone receptor (PR), and human EGF-like receptor 2 (HER2). MiR-193 always acted as an oncogene and promoted toxic aldehyde accumulation and tyrosine hydroxylase dysfunction. The purpose of this study is to explore the function of miR-193 in triple-negative breast cancer.

PATIENTS AND METHODS

Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was performed to examine the mRNA level of miR-193 expression in 50 cases of TNBC tissues and para-cancerous specimens. Also, the relation between miR-193 level and the overall survival of TNBC patient was analyzed. MiR-193 mimic and miR-193 inhibitor oligos, as well as the corresponding negative control, were synthesized from RiboBio (Guangzhou, China).

RESULTS

MiR-193 expression was higher in triple-negative breast cancer tissues and cell lines than the corresponding adjacent non-tumor tissues and normal cell lines. Upregulation of miR-193 predicted poor prognosis of TNBC patients. Overexpression of miR-193 promoted cell proliferation and invasion, while that was suppressed by the knockdown of miR-193. MiR-193 binds to the 3'-UTR of an inhibitor of growth family member 5 (ING5) mRNA to mediate the expression of ING5 in TNBC cells. The knockdown of miR-193 inhibited cell invasion-mediated epithelial-mesenchymal transition (EMT). Furthermore, the knockdown of miR-193 suppressed cell proliferation through the ING5/phosphatidylinositol 3-hydroxy kinase/protein kinase B (PI3K/AKT) signal pathway.

CONCLUSIONS

MiR-193 enhanced cell invasion-mediated EMT and improved cell proliferation through the ING5/PI3K/AKT signal pathway in triple-negative breast cancer. The newly identified miR-193/ING5/PI3K/AKT axis provides novel insight into the pathogenesis of triple-negative breast cancer.