Effect Of Bisphenol P And Bisphenol M In Promoting Metastasis Of Triple-negative Breast Cancer And Its Molecular Mechanism

Breast cancer is the most common malignancy in women worldwide.In 2020,there were as many as 2.26 million new cases of breast cancer worldwide,and the incidence is increasing every year.Triple-negative breast cancer(TNBC)accounts for 10-20% of breast cancers.It has a high rate of distal organ metastasis,is the most malignant subtype of breast cancer.The development of breast cancer is closely related to genetic phenotype and environmental factors.Bisphenols are widely used as environmental estrogens in industrial production,and bisphenol A(BPA)is a known risk factor for breast cancer development and metastasis.In contrast,bisphenol P(BPP)and bisphenol M(BPM),structural analogues of BPA,are widely used but their effects on the pathophysiological processes of the organism are unclear.This master’s thesis explores the effects of BPP and BPM on triple-negative breast cancer and their molecular mechanisms.Objective: To elucidate the effects of BPP and BPM in promoting TNBC metastasis.To clarify the molecular mechanisms of BPP and BPM in promoting TNBC metastasis.Contents:(1)To clarify the effects of BPP and BPM on the growth and metastasis of murine-derived(4T1)and human-derived(MDA-MB-231)triple-negative breast cancer cells at the molecular level.(2)To clarify the effects of BPP and BPM on the growth and metastasis of triple-negative breast cancer in mice models.(3)To analysis the molecular mechanism of BPP and BPM to promote TNBC metastasis.Methods:(1)MTT was performed to detect the effects of different concentrations of BPP and BPM on the proliferation ability of 4T1 and MDA-MB-231 cells.Wound healing assay and invasion assay were performed to detect the effects of different concentrations of BPP and BPM on the migration and invasion ability of 4T1 and MDA-MB-231 cells,respectively.(2)BALB/c mice were inoculated with 4T1 cells subcutaneously to establish a subcutaneous tumor model,and the effects of BPP and BPM on tumor weight were analyzed.Tail vein inoculation of MDA-MB-231-i RFP in nude mice combined with tail vein injection of 4T1-Luc cells in BALB/c mice was used to construct a lung metastatic tumor model of breast cancer,and small animal live imaging was performed to observe the effects of BPP and BPM on the colonization of breast cancer cells in lung tissue to form lung metastases.(3)Western blot and immunohistochemistry were used to detect the expression of metastasis-related protein markers in vitro and in vivo after BPP and BPM treatment,respectively.Whether BPP and BPM affect tumor cell migration and invasion through PI3K/AKT signaling pathway by inhibitor intervention.Results:(1)BPP and BPM did not affect the proliferation of TNBC cells,but promoted their migration and invasion.(2)BPP and BPM did not affect the weight of subcutaneous tumors in BALB/c mice,but promoted the colonization of triple-negative breast cancer cells in the lungs of BALB/c nude mice and BALB/c mice.(3)In vivo and in vitro experiments demonstrated that BPP and BPM exposure upregulated the expression levels of metastasisrelated proteins N-cadherin,MMP-9,MMP-2 and Snail.Activation of PI3K/AKT signaling pathway by BPP and BPM treatment of TNBC cells,reversal of the pro-migration and invasion effects of BPP and BPM on TNBC cells using PI3K/AKT inhibitors,and down-regulation of Snail protein expression.Conclusions: BPP and BPM can induce EMT process of TNBC by activating PI3K/AKT signaling pathway,thus promoting the metastasis of TNBC in vivo and in vitro.