Effect Of Cancer-Derived Exosomes On The Biological Function Of MCF-7 Cells In Breast Cancer

Objective:To investigate the effects of breast cancer cell-derived exosomes on the biological role of MCF-7 cells in breast cancer.Methods :The exosomes in the culture medium of breast cancer MCF-7 cells were extracted and purified by ultracentrifugation,and the morphological characteristics and diameter of exosomes derived from MCF-7cells were observed by universal transmission electron microscopy.Exosome marker proteins CD9 and CD81 were identified using by protein immunoblotting assay.The effects of MC-F-7 cell derived exosomes on the proliferation,clone formation,invasion,migration,apoptosis and epithelial mesenchymal transition ability of MCF-7 cells were examined by MTT assay,clone formation assay,cell scratch assay,cell invasion assay,immunoblotting assay and flow cytometry assay.Results:Transmission electron microscopy showed that the shape of exosomes was typical cupula-like or concave hemispherical structure with a diameter of 40-110 nm;protein immunoblotting showed that exosomal marker proteins CD9 and CD81 were significantly enriched;The results of MTT experiments show that the proliferation ability of MCF-7 cells in the experimental group was significantly enhanced compared with that in the control group(p<0.01),the clonal formation experiment showed that exosomes significantly enhanced the clonal ability of MCF-7 cells(p<0.01),Flow cytometry analysis showed that the percentage of apoptotic cells was significantly lower in exosome-stimulated breast cancer cells than in control cells(p <0.05);the results of cell scratch experiments showed that MCF-7-derived exosomes could significantly promote the migration of MCF-7 cells(p<0.001).The results of Transwell invasion showed that the migration and invasion ability of MCF-7 cells in the experimental group was significantly enhanced compared with that of the control group(p<0.001).Western blot results showed that breast cancer-derived exosomes increased the expression of N-cadherin,vimentin and decreased the expression of E-cadherin,which promoted the EMT process in breast cancer(p < 0.01).Conclusion:Breast cancer cell-derived exosomal strength enhances cell proliferation in tumor cells,clonogenesis,invasion,metastatic capacity and induce apoptosis.It shows that tumor-derived exosomes can act as mediators of cell-to-cell signal transduction and play an indispensable role in promoting tumor growth and the information transfer of tumor metastasis.