Fig. 4.

Metformin could inhibit the tumor growth in vivo. A, B, C The tumor growth of groups treated with metformin was significantly slower than that of groups not treated with metformin in nude mice. d, e Metformin could upregulate the CEBPB expression but downregulate the PDL1 expression in tumor tissues. f–h Metformin and atezolizumab could inhibit the tumor growth in C57BL/6 J mice, respectively, and atezolizumab and metformin has synergistic effect. i The immunohistochemistry staining showed that the expression PDL1 decreased in tumor of metformin group and atezolizumab group and decreased most significantly compared with those of control group