title: A benzimidazole fungicide, benomyl, and its metabolite, carbendazim, induce aromatase activity in a human ovarian granulose-like tumor cell line (KGN).
abstract: Endocrine disruptor chemicals are known to cause a range of abnormalities in sexual differentiation and reproduction. One mechanism underlying such effects may be via alteration of aromatase activity, which is responsible for estrogen production. A good screening system for identifying endocrine disruptors has long been desired. We have recently established a human ovarian granulosa-like tumor cell line, KGN, which possesses a relatively high level of aromatase expression and is considered a useful mammalian model for investigating the in vitro effects of various chemicals on aromatase activity. In this study we screened 55 different candidate chemicals for endocrine disruptors by assaying aromatase activity. Only benomyl, known as both a benzimidazole fungicide and a microtubule-interfering agent, was found to induce aromatase activity in association with increased levels of aromatase mRNA in KGN cells. The effect of benomyl was presumed to be mediated by its metabolite carbendazim, because it produced an effect equivalent to that of benomyl. The mechanism underlying the benomyl-induced increase in aromatase activity appears independent of the cAMP-protein kinase A pathway. Treatment with taxol, another class of microtubule-interfering agents, also caused induction of aromatase in KGN cells. Both benomyl and taxol changed KGN cell morphology, including the development of cell roundness and a disorganized network of microtubules. These results indicate that benomyl is a potential endocrine disruptor that provides a novel estrogenicity and operates through a microtubule-interfering mechanism.
authors.affiliation: Department of Medicine and Bioregulatory Science (Third Department of Internal Medicine), Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Morinaga
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Yanase
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Nomura
authors.forename: Taijiro
authors.initials: T
authors.lastname: Okabe
authors.forename: Kiminobu
authors.initials: K
authors.lastname: Goto
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Harada
authors.forename: Hajime
authors.initials: H
authors.lastname: Nawata
mesh_terms: D001141:Aromatase / Q000096:biosynthesis* / Q000235:genetics; D001542:Benomyl / Q000378:metabolism / Q000494:pharmacology*; D001562:Benzimidazoles / Q000494:pharmacology*; D002219:Carbamates; D045744:Cell Line, Tumor; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000235:genetics; D000242:Cyclic AMP / Q000096:biosynthesis / Q000235:genetics; D004790:Enzyme Induction; D005260:Female; D005659:Fungicides, Industrial / Q000378:metabolism / Q000494:pharmacology*; D006107:Granulosa Cells / Q000187:drug effects* / Q000378:metabolism*; D006801:Humans; D010750:Phosphoproteins / Q000235:genetics; D011374:Progesterone / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D020218:Response Elements / Q000502:physiology; D014158:Transcription, Genetic / Q000187:drug effects / Q000502:physiology; D000098682:Steroidogenic Acute Regulatory Protein
chemical_list: D001562:Benzimidazoles; D002219:Carbamates; D005659:Fungicides, Industrial; D010750:Phosphoproteins; D012333:RNA, Messenger; D000098682:Steroidogenic Acute Regulatory Protein; D011374:Progesterone; D000242:Cyclic AMP; D001141:Aromatase; D002786:Cholesterol Side-Chain Cleavage Enzyme; C006698:carbendazim; D001542:Benomyl