Metformin suppresses hypoxia-inducible factor-1α expression in cancer-associated fibroblasts to block tumor-stromal cross-talk in breast cancer
SHAO Shan
BAI Weichao
ZHOU Pengcheng
LUO Minna
ZHAO Xinhan
LEI Jianjun
Abstract：Objective To investigate the mechanism of metformin for regulating tumor-stromal cell cross-talk in breast cancer.Methods Tumor associated fibroblasts(CAFs)co-cultured with breast cancer cells were treated with metformin,and the changes in expressions of hypoxia-inducible factor-1α(HIF-1α),p-AMPK,stroma-derived factor-1(SDF-1)and interleukin-8(IL-8)in the CAFs were detected using ELISA,RT-qPCR or Western blotting;Transwell assay was used to evaluate the invasiveness of the tumor cells and its changes following treatment with exogenous SDF-1,IL-8 and TGF-β1.The effects of HIF-1α shRNA or overexpression plasmid,AMPK shRNA,and treatment with OG(a proline hydroxylase inhibitor)or 2-OXO(a proline hydroxylase activator)were examined on p-AMPK,HIF-1α,SDF-1 and IL-8 expressions and invasiveness of the CAFs.Results Metformin treatment significantly increased the expression levels of p-AMPK,SDF-1 and IL-8(P<0.05)and decreased HIF-1α expression(P<0.05)without affecting AMPK expression level(P>0.05)in the CAFs.The invasion ability of metformin-treated breast cancer cells was significantly decreased(P<0.05).Exogenous SDF-1 and IL-8,HIF-1α overexpression,and OG-induced upregulation of HIF-1α all significantly attenuated the inhibitory effects of metformin on breast cancer cell invasion(P<0.05)and HIF-1α,SDF-1 and IL-8 expressions in CAFs(P<0.05).Transfection with HIF-1α shRNA or treatment with 2-OXO significantly decreased the invasiveness of breast cancer cells(P<0.05).P-AMPK knockdown significantly suppressed the inhibitory effect of metformin on HIF-1α expression in CAFs and on invasion of breast cancer cells(P<0.05).Treatment with TGF-β1 partially decreased the inhibitory effect of metformin on HIF-1α expression in CAFs and invasiveness of the breast cancer cells(P<0.05).Conclusion Metformin suppresses HIF-1α expression in CAFs to block tumor-stromal cross talk in breast cancer.
Keywords：cancer-associated fibroblastshypoxia-inducible factor-1αmetforminphospho-AMPKtumor microenvironment
Publication Date：2024-03-20
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：9( 428-436 )