title: Acetaminophen-induced proliferation of estrogen-responsive breast cancer cells is associated with increases in c-myc RNA expression and NF-kappaB activity.
abstract: Studies reported here tested the hypothesis that acetaminophen stimulates proliferation of E2-responsive cells by inducing expression of E2-regulated genes. Ribonuclease protection assays compared the effects of acetaminophen and E2 on expression of selected genes (c-myc, c-fos, cyclin D1, bcl-2, bax, gadd45, mcl-1, p53, p21(CIP1/WAF1), and bcl-xL) in E2-responsive breast cancer (MCF-7) and endometrial adenocarcinoma (Ishikawa) cells as well as in E2-nonresponsive (MDA-MB-231) breast cancer cells. Acetaminophen and E2 increased c-myc RNA levels in MCF-7 cells, consistent with a mitogenic activity of these compounds in MCF-7 cells. However, the magnitude and time course of acetaminophen and E2 induction of c-myc differed. Neither acetaminophen nor E2 induced c-myc in MDA-MB-231 cells, whereas E2, but not acetaminophen, weakly induced c-myc expression in Ishikawa cells. Furthermore, in these 3 cell types, the expression patterns of the other genes differed dramatically in response to acetaminophen and to E2, indicating that acetaminophen does not activate ER as a transcription factor in the same manner as does E2. Additionally, gel shift assays demonstrated that in MCF-7 cells, acetaminophen increased NF-kappaB activity approximately 40% and did not alter AP-1 activity, whereas E2 increased AP-1 activity approximately 50% and did not increase NF-B activity. These studies indicate that acetaminophen effects on gene expression and cell proliferation depend more on cell type/context than on the presence of ER.
authors.affiliation: Department of Biochemistry and Molecular Pharmacology, West Virginia University, Morgantown, West Virginia 26506-9142, USA.
authors.forename: Samantha L
authors.initials: SL
authors.lastname: Gadd
authors.forename: Gerry
authors.initials: G
authors.lastname: Hobbs
authors.forename: Michael R
authors.initials: MR
authors.lastname: Miller
mesh_terms: D000082:Acetaminophen / Q000494:pharmacology*; D018712:Analgesics, Non-Narcotic / Q000494:pharmacology*; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D002455:Cell Division / Q000187:drug effects; D004958:Estradiol / Q000494:pharmacology*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D016328:NF-kappa B / Q000378:metabolism*; D009376:Neoplasms, Hormone-Dependent / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D011959:Receptors, Estradiol / Q000235:genetics; D014407:Tumor Cells, Cultured
chemical_list: D018712:Analgesics, Non-Narcotic; D016328:NF-kappa B; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D011959:Receptors, Estradiol; D000082:Acetaminophen; D004958:Estradiol