The Role And Mechanism Of ACEI On Chemosensitization Of Colorectal Cancer

Objective:Angiotensin-converting enzyme inhibitors(ACEI)are commonly used in the clinical treatment of hypertension.5-fluorouracil(5-FU)is currently the preferred chemotherapy drug for colorectal cancer,but the congenital chemoresistance and rapid acquired chemoresistance of the tumor are one of the important reasons for the poor chemotherapy effect of colorectal cancer.Therefore,it is of great clinical significance to explore the reversal of chemoresistance of colorectal cancer.The purpose of this study was to investigate the role of ACEI in chemosensitization of colorectal cancer,and to explore the possible synergistic effect and possible mechanism of ACEI and 5-FU.Methods:CCK-8:the effect of 5-FU ACEI alone and in combination on the proliferation of two colon cancer cell lines HCT116 and SW620 was detected.FACS:flow cytometry was used to detect the apoptosis of HCT116 and SW620 cells when ACEI was used alone or in combination with 5-FU.Transwell/Matrigel and scratch test:the invasion and migration ability of HCT116 and SW620 cells in the control group(Co),ACEI group(ACEI),5-FU group(5-FU)and combined group(ACEI+5FU)were detected.Animal experiments:in this study,we first constructed two animal models of tumor bearing mice,HCT116 and SW620,and divided them into four groups to start administration:control group(Co),ACEI group(ACEI),5-FU group(5-FU),and combined group(ACEI+5FU).The tumor-forming capacity and tumor size of mice in the single and combined groups were observed.Western Blot and immunohistochemistry:Detection of colon cancer cells and tumor tissue protein Ki67 associated with tumor cell proliferation and apoptosis related proteins Caspase 3,VEGF-α and CD31 protein involved in tumor angiogenesis,Vimentin E-cadherin and Snail protein involved in tumor metastasis EMT process,as well as the NF-κB/STAT3 signaling pathway and regulation related proteins P65/p-P65,STAT3/p-STAT3,CyclinD1,C-myc,MMP-2,MMP-9,Bcl-2,and XIAP expression.Results:The results of cell proliferation detection showed that ACEI had no obvious inhibitory effect on the proliferation of colon cancer cells(P<0.01),but greatly increased the inhibitory effect of 5-FU on the proliferation of colon cancer cells(P<0.01).Flow flow apoptosis detection also found that ACEI enhanced 5-FU-induced apoptosis.Transwell and scratch experiments also showed that both ACEI and 5-FU had limited effect on the invasion and migration of colon cancer cells,while the combination of 5-FU and ACEI significantly inhibited the invasion and migration of colon cancer cells.In animal experiments,compared with the single ACEI group or the single 5-FU group,nude mice treated with ACEI and 5-FU had the smallest tumor size,the lightest tumor weight,significantly reduced liver metastasis and abdominal metastasis,and ACEI did not significantly increase the hepatorenal side effects of 5-FU on nude mice.Western Blot and immunohistochemical detection showed that ACEI and 5-FU synergistically inhibit the expression of tumor angiogenesis-related proteins VEGF-α and CD31,NF-κB/STAT3 signaling pathway and regulated downstream related genes,down-regulate the EMT protein Vimentin,Snail and up-regulate E-cadherin,and inhibit the expression of the proliferation factor Ki67 and the apoptosis-inducing protein Caspase-3.Conclusion:ACEI significantly increased the chemosensitivity of colon cancer cells to 5-FU,and the combination of the two drugs synergically inhibited the growth and metastasis of colon tumors without increasing the toxic and side effects.The mechanism of action may be through inhibiting tumor angiogenesis,NF-κB/STAT3 signaling pathway and regulating the expression of related proteins.Our study provides a theoretical and experimental basis for the clinical application of ACEI to reverse chemoresistance of colorectal cancer.