Bisphenol P and bisphenol M promote triple-negative breast cancer metastasis through activation of AKT pathways

Bisphenol P (BPP) and bisphenol M (BPM) are increasing in our living environment as analogues of bisphenol A (BPA), but little is known about their biological effect. In this study, we investigated the effects of low to medium dose exposure of BPP and BPM on triple negative breast cancer (TNBC). We found that BPP and BPM exposure didn't affect proliferation of TNBC cell lines MDA-MB-231 and 4 T1, but significantly promoted cells migration and invasion. The effect of BPP and BPM on promoting TNBC metastasis was further confirmed in mouse models. Low concentrations of BPP and BPM significantly increased the expression of epithelial-mesenchymal transition (EMT) marker and related proteins such as N-cadherin, MMP-9, MMP-2 and Snail, and also enhanced phosphorylation of AKT both in vitro and in vivo. When PI3K inhibitor wortmannin was applied to specifically inhibit phosphorylation of AKT, the expression of target genes markedly decreased, and the TNBC metastasis induced by low-concentration BPP and BPM were reversed. In conclusion, these results showed that PI3K/AKT signaling regulate BPP/BPM-induced metastasis of TNBC by triggering EMT. This study provides insights into the effects and the potential mechanisms of BPP and BPM on TNBC, raising concerns about the risk of using these two bisphenols as the alternative of BPA.