Cancer-Associated Fibroblasts Autophagy Enhances Progression of Triple-Negative Breast Cancer Cells.

Background: Cancer-associated fibroblasts (CAFs) are key factors in malignant tumor initiation, progression, and metastasis. However, the effect of CAFs autophagy on triple-negative breast cancer (TNBC) cells is not clear. In this study, the growth effect of TNBC cells regulated by CAFs autophagy was evaluated. Material/Methods: CAFs were obtained from invasive TNBC tumors and identified by Western blot and immunofluorescence staining assay. CAFs were co-cultured with TNBC cells, and migration and invasion were evaluated by Matrigel-coated Transwell and Transwell inserts. TNBC cells growth was detected by MTT assay, and epithelial-mesenchymal transition (EMT) regulated by CAFs was evaluated by Western blot assay. Results: CAFs were identified by the high expression of a-smooth muscle actin (alpha-SMA) protein. Autophagy-relevant Beclin 1 and LC3-II/I protein conversion levels in CAFs were higher than those in NFs (P<0.05). TNBC cells migration, invasion, and proliferation levels were significantly improved in the CAFs-conditioned medium (CAFsCM) group, compared with the other 3 groups (P<0.05). TNBC cells vimentin and N-cadherin protein levels were upregulated and E-cadherin protein level was downregulated in the CAFs-CM group compared with the control group (P<0.05). Further study indicated b-catenin and P-GSK-3 beta protein levels, which are the key proteins in the Wnt/beta-catenin pathway, were upregulated in the CAFs-CM group compared with the control group (P<0.05). Conclusions: Our data demonstrated CAFs autophagy can enhance TNBC cell migration, invasion, and proliferation, and CAFs autophagy can induce TNBC cells to engage in the EMT process through the Wnt/ b-catenin pathway.