Effect Of Chlorin E6 Photodynamic Therapy On Exosomes Of Colon Cancer Cells With Different Metastatic Potential

Objective: Observe the effects of Chlorin e6 photodynamic theraly(Ce6-PDT)on the morphology,particle size and secretion of exosomes of human colon cancer SW480 and SW620,and the role of exosomes in the epithelial-mesenchymal transformation(EMT)of colon cancer,so as to provide scientific data for the mechanism of Ce6-PDT in the treatment of colon cancer.Methods: 1.The morphological changes of SW480 and SW620 cells after Ce6-PDT were observed by fluorescence inverted microscope.2.The survival inhibition rate of the two kinds of cells after Ce6-PDT was detected by MTT method.3.The cell migration ability was detected by scratch test.4.The morphological changes of exosome of the two kinds of cells after Ce6-PDT were observed by transmission electron microscope.5.The changes of exosome concentration and particle size of the two kinds of cells after Ce6-PDT were observed by nanoparticle tracer analysis(NAT).6.Western blotting was used to detect the expression of proteins CD63,CD9,HSP70 and Calnexin in cells after Ce6-PDT.7.The changes of proliferation and migration ability of two types cells were observed by exosome co-incubation experiment.8.Western Blot assay was used to detect the expression of EMT-related proteins Vimentin and E-cadherin in cells after co-incubation.Results: 1.After Ce6-PDT,the cell morphology changed obviously,the cell became round and shrunk,the growth inhibition rate of cell increased gradually,compared with the control group,the difference of cell growth inhibition rate of each experimental group was statistically significant(P < 0.05);compared with the control group,there was no significant difference in the scratch area of the two kinds of cells when the concentration of Ce6 was 0.125,0.25,0.5 ? g / ml,but when the concentration of Ce6 was1.0 ? g / ml and higher,the scratch area was larger than that of the control group.2.After Ce6-PDT,the exosomes of SW480 and SW620 showed typical sunken cup-shaped structure,and there was no significant difference in shape.3.After Ce6-PDT,theconcentration of exosome particles secreted by cell was significantly lower than that of the control group(P < 0.001).There was no significant difference in the range of exocrine particle size between SW480 and SW620 cells control group and Ce6-PDT treatment group(P > 0.05).4.CD63 protein was expressed in exosome of SW480 and SW620.After Ce6-PDT treatment of SW620 cells,the expression of CD63 in exosome decreased,but there was no expression of CD63 in cell lysate,the expression of CD9 in exosome was higher than that in cell lysate,and in exosome,the expression of CD9 decreased after Ce6-PDT treatment,and there was no significant difference in expression of HSP70 protein in cell lysate and exosome.Calnexin protein was expressed in cell lysis,but Calnexin protein was not expressed in exosome.5.Exosomes in SW620 cell control group and Ce6-PDT group could promote the proliferation of SW480 and SW620 cells(P <0.001).6.Compared with the cells not incubated with exosomes,the scratches of SW480 and SW620 cells were significantly reduced after co-incubation with untreated exosomes of SW620 cells,and there was no significant difference in scratch area between SW480 and SW620 cells after co-incubation with exosomes of SW620 cells treated with Ce6-PDT.7.Compared with the cells not incubated with exosomes,the expression of Vimentin protein in SW480 cells and SW620 cells was significantly increased(P < 0.001),while the expression of E-cadherin protein in SW480 cells was significantly decreased(P < 0.001).The expression of E-cadherin protein in SW620 cells did not change significantly(P >0.001).When SW480 and SW620 cells were co-incubated with exosomes secreted by SW620 cells treated with Ce6-PDT,the expression of Vimentin protein did not change significantly,while the expression of E-cadherin protein in SW480 cells decreased,and the expression of E-cadherin protein in SW620 cells did not change significantly.Conclusions: 1.Ce6-PDT can induce the changes in SW480 and SW620 cell morphology,and inhibit the proliferation and migration of SW480 and SW620 cells.2.Ce6-PDT does not cause morphological changes of exosomes in SW480 and SW620 cells.3.Ce6-PDT inhibits the release of exosomes from SW480 and SW620 cells,but Ce6-PDT does not cause the change exosome size.4.SW620 exosome can promote the proliferation of SW480 and SW620 cells.5.SW620 exosome can promote the migration of SW480 and SW620 cells,while Ce6-PDT can inhibit the promoting effect of exosome on the migration of SW480 and SW620 cells.6.SW620 exosomes can induce EMT transformation in SW480 cells.