Title : ATM and p53 regulate FOXM1 expression via E2F in breast cancer epirubicin treatment and resistance.

Pub. Date : 2011 Jun

PMID : 21518729






10 Functional Relationships(s)
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Protein Name
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1 ATM and p53 regulate FOXM1 expression via E2F in breast cancer epirubicin treatment and resistance. Epirubicin forkhead box M1 Homo sapiens
2 In this report, we investigated the role and regulation of forkhead box M1 (FOXM1) in breast cancer and epirubicin resistance. Epirubicin forkhead box M1 Homo sapiens
3 We generated epirubicin-resistant MCF-7 breast carcinoma (MCF-7-EPI(R)) cells and found FOXM1 protein levels to be higher in MCF-7-EPI(R) than in MCF-7 cells and that FOXM1 expression is downregulated by epirubicin in MCF-7 but not in MCF-7-EPI(R) cells. Epirubicin forkhead box M1 Homo sapiens
4 We generated epirubicin-resistant MCF-7 breast carcinoma (MCF-7-EPI(R)) cells and found FOXM1 protein levels to be higher in MCF-7-EPI(R) than in MCF-7 cells and that FOXM1 expression is downregulated by epirubicin in MCF-7 but not in MCF-7-EPI(R) cells. Epirubicin forkhead box M1 Homo sapiens
5 We generated epirubicin-resistant MCF-7 breast carcinoma (MCF-7-EPI(R)) cells and found FOXM1 protein levels to be higher in MCF-7-EPI(R) than in MCF-7 cells and that FOXM1 expression is downregulated by epirubicin in MCF-7 but not in MCF-7-EPI(R) cells. Epirubicin forkhead box M1 Homo sapiens
6 We also established that there is a loss of p53 function in MCF-7-EPI(R) cells and that epirubicin represses FOXM1 expression at transcription and gene promoter levels through activation of p53 and repression of E2F activity in MCF-7 cells. Epirubicin forkhead box M1 Homo sapiens
7 Moreover, transient promoter transfection assays showed that epirubicin and its cellular effectors p53 and E2F1 modulate FOXM1 transcription through an E2F-binding site located within the proximal promoter region. Epirubicin forkhead box M1 Homo sapiens
8 Chromatin immunoprecipitation analysis also revealed that epirubicin treatment increases pRB (retinoblastoma protein) and decreases E2F1 recruitment to the FOXM1 promoter region containing the E2F site. Epirubicin forkhead box M1 Homo sapiens
9 We also found ataxia-telangiectasia mutated (ATM) protein and mRNA to be overexpressed in the resistant MCF-7-EPI(R) cells compared with MCF-7 cells and that epirubicin could activate ATM to promote E2F activity and FOXM1 expression. Epirubicin forkhead box M1 Homo sapiens
10 In summary, our data show that ATM and p53 coordinately regulate FOXM1 via E2F to modulate epirubicin response and resistance in breast cancer. Epirubicin forkhead box M1 Homo sapiens