Abstract: Objective To explore the relationship between miR-205 and JAK2 / STAT3 in the development of triple negative breast cancer (TNBC), so as to provide new ideas for the treatment of TNBC. Methods qRT-PCR and Western blotting were used to detect the expression levels of miR-205 and JAK2 in cancer tissues and adjacent tissues. The expression levels of JAK2 pathway related proteins were detected by Western blotting in MDA-MB-231 cell line after cells were transfected with miR-205 mimic, miR NC, pcDNA3. 1 JAK2 or pcDNA3. 1 NC. The migration of MDA-MB-231 cells was detected by wound healing assay, the invasiveness of cells was detected by transwell test, the growth ability of MDA-MB-231 cells was analyzed by colony formation assay, the apoptosis was analyzed by flow cytometry, and the interaction between miR-205 and JAK2 was verified by dual luciferase gene reporter assay. Results In TNBC tissues, the expression level of miR-205 decreased and the expression level of JAK2 increased. After overexpression of miR-205 in MDA-MB-231 cells, the capacity of growth, invasion and metastasis of cells were suppressed, while the apoptosis rate was significantly increased. On the contrary, after overexpression of JAK2 in the MDA-MB-231 cells, the capacity of growth, invasion and metastasis of cells were enhanced, and the apoptosis rate was significantly reduced. The dual luciferase gene reporter assay revealed that miR-205 can target and inhibit JAK2 activity. Conclusion miR-205 can target JAK2 / STAT3 pathway, inhibit the growth, invasion and metastasis of TNBC cells, and promote the apoptosis of TNBC cells.

Key words: miR-205, JAK2, STAT3, triple negative breast cancer, metastasis