title: Growth retardation in human cervical dysplasia-derived cell lines by beta-carotene through down-regulation of epidermal growth factor receptor.
abstract: We used newly established cervical dysplasia-derived cell lines to elucidate a molecular mechanism of the preventive action of beta-carotene in cervical multi-step carcinogenesis. Liposomal beta-carotene was added to the culture medium for human cervical dysplasia cell lines, CICCN-2 from cervical intraepithelial neoplasia grade I (CIN I), CICCN-3 from CIN II, and CICCN-4 from CIN III, and human cervical carcinoma-derived cell lines such as CICCN-6, CICCN-18, and HeLa cells. beta-Carotene (10 mumol/L) induced significant growth retardation in three cervical dysplasia cell lines but not in three cervical carcinoma-derived cell lines. Binding activities of epidermal growth factor (EGF) and cellular amounts of either messenger RNA for EGF receptor gene or EGF receptor protein were all highest in CICCN-4 cells. Cell surface binding, as well as internalization, of 125I-labeled EGF was rapidly reduced after beta-carotene treatment in dysplasia cell lines and 170-kD protein bands of EGF receptor disappeared from protein immunoblots at day 3 of the treatment. Cellular amounts of EGF receptor messenger RNA remained constant until day 3 of the treatment and were substantially reduced after day 7. Chromatin condensations, morphologic evidence for apoptotic cell death, were observed at day 1 by staining. From these results, we contend that prevention of cervical carcinogenesis by beta-carotene is due to induction of apoptosis in cervical dysplastic cells, which are premalignant cells in cervical multi-step carcinogenesis, via down-regulation of EGF receptor protein.
mesh_terms: D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D000975:Antioxidants / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002338:Carotenoids / Q000494:pharmacology*; D015536:Down-Regulation; D004815:Epidermal Growth Factor / Q000378:metabolism; D066246:ErbB Receptors / Q000032:analysis / Q000187:drug effects* / Q000235:genetics; D005260:Female; D006801:Humans; D012333:RNA, Messenger / Q000032:analysis; D014407:Tumor Cells, Cultured; D002583:Uterine Cervical Neoplasms / Q000473:pathology / Q000517:prevention & control*; D019207:beta Carotene; D002578:Uterine Cervical Dysplasia / Q000473:pathology / Q000517:prevention & control*
chemical_list: D016588:Anticarcinogenic Agents; D000975:Antioxidants; D012333:RNA, Messenger; D019207:beta Carotene; D002338:Carotenoids; D004815:Epidermal Growth Factor; D066246:ErbB Receptors