The Mechanisms Of T-MSC Promoting CXCL5 Expression And Angiogenesis In Colorectal Cancer

Objectives: To investigate the molecular mechanism of tumor-associated mesenchymal stem cells in promoting secretion of CXCL5 in colorectal cancer cells,and the effects of CXCL5 and CCL19 on angiogenesis in colorectal cancer.Methods: Primary mesenchymal stem cells(MSC)were extracted from colorectal cancer tissues and normal tissues.MSCs were identified by stem cell differentiation assay,flow cytometry and immunofluorescence assay,and MSC supernatant was used to detect the effect on the expression of CXCL5 in colorectal cancer cells.q PCR was used to screen differentially expressed genes of T-MSC and N-MSC,and the molecular mechanism of CCL7 regulating CXCL5 expression was further confirmed by western blot,neutralizing antibody,inhibitor,chromatin immunoprecipitation(CHIP)and dual luciferase reporter gene assay.The effects of CXCL5 and CCL19 on angiogenesis of colorectal cancer were verified by endothelial tube formation assay,subcutaneous tumor formation model and immunohistochemical staining(IHC),and the downstream signaling pathway was studied by western blot and inhibitor.Results: Stem cell differentiation assay,flow cytometry and immunofluorescence experiments showed that the extracted MSC had the potential of osteogenic,adipogenic and chondrogenic differentiation,and with high expression of MSC-related markers.Western blot and RT-PCR results showed that T-MSC could promote the expression of CXCL5 in colorectal cancer cells.q PCR results indicated that CCL7 was high expressed in T-MSC.After treatment with anti-CCL7 neutralizing antibody and si-CCR1,the ability of T-MSC supernatant to promote CXCL5 expression in colorectal cancer cells was significantly reduced.Further studies revealed that the transcription factor KLF5 which was regulated by CCL7,can bind to the promoter region of CXCL5 and promote its transcription.Endothelial tube formation assay and subcutaneous tumor formation model in nude mice suggest that CXCL5 can promote angiogenesis in colorectal cancer,and CCL19 can inhibit angiogenesis in colorectal cancer.The anti-angiogenic effect of CCL19 is through ERK / Elk-1 / HIF-1α / VEGF-A pathway achieved.The results of IHC suggest that CXCL5 and CCL19 may have some mutual antagonism.Conclusion: T-MSC derived CCL7 can specifically bind to CCR1 and promote the secretion of CXCL5 in colorectal cancer cells by activating KLF5 signaling pathway.Overexpression of CXCL5 in colorectal cancer can promote tumor angiogenesis,while CCL19 can inhibit tumor angiogenesis via ERK / Elk-1 / HIF-1α / VEGF-A pathway,and there is some mutual antagonism between CXCL5 and CCL19.