Objective To assess the efficacy of pirfenidone combined with PD-L1 inhibitor for treatment of bladder cancer in a mouse model and its effect on tumor immune microenvironment modulation.Methods Forty C57BL/6 mouse models bearing ectopic human bladder cancer xenografts were randomized into control group,PD-L1 inhibitor group,pirfenidone group and combined treatment group(n=10).After successful modeling,PD-L1 inhibitor treatment was administered via intraperitoneal injection at 12.5 mg/kg every 3 days,and oral pirfenidone(500 mg/kg)was given on a daily basis.The survival rate of the mice and tumor growth rate were compared among the 4 groups.The expressions of CD3,CD8,CD45,E-cadherin and N-cadherin in the tumor tissues were detected with immunohistochemistry after the 21-day treatment,and bone marrow-derived suppressor cells(MDSCs)were observed with immunofluorescence staining;serum levels of alanine aminotransferase(ALT),aspartate aminotransferase(AST),urea nitrogen(BUN),creatinine(CRE)and lactate dehydrogenase(LDH-L)were analyzed using an automated biochemical analyzer.Results Treatment with PD-L1 inhibitor and pirfenidone alone both significantly decreased tumor growth rate and tumor volume at 21 days(P<0.05),but the combined treatment produced an obviously stronger inhibitory effect(P<0.05).PD-L1 inhibitor and pirfenidone alone significantly increased E-cadherin expression and decreased N-cadherin expression in the tumor tissue(P<0.05).The two treatments both significantly increased the percentage of CD3+,CD8 and CD45+ T cells and decreased the percentage of Ly-6G+CD11b+MDSCs in the tumor tissue,and these changes were more obvious in the combined treatment group(P<0.05).No significant differences were found in serum ALT,AST,BUN,CRE or LDH-L levels among the 4 groups(P>0.05).Conclusion Combined treatment with pirfenidone and PD-L1 inhibitor significantly inhibits the progression of bladder cancer in mice possibly by regulating tumor immune microenvironment and inhibiting epithelial-mesenchymal transition of the tumor cells.
维普
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