Accession Number : ADA330243
Title : The Role and Regulation of TNF-Alpha in Normal Rat Mammary Gland during Development and in Breast Cancer.
Descriptive Note : Annual rept. 1 Jul 96-30 Jun 97,
Corporate Author : HEALTH RESEARCH INC BUFFALO NY
Personal Author(s) : Varela, Linda M. ; Ip, Margot M.
PDF Url : ADA330243
Report Date : JUL 1997
Pagination or Media Count : 36
Abstract : Our laboratory has shown that TNF can regulate normal mammary epithelial cell (MEC) growth, morphogenesis, and, under certain circumstances, functional differentiation in a manner similar to LGF. Since INF has been shown to up-regulate EGF receptor (EGFR) expression and function in other systems, the current studies were undertaken to determine whether TNF action in MEC was indirect through-stimulation of the EGFR. An inhibitor of EGFR tyrosine kinase activity, PDl58780, failed to block proliferation induced by 40 ng/ml TNF and only partially inhibited growth in response to 2 ng/ml TNF. PD158780 was also unable to suppress the extensive morphological development induced by either TNF concentration. In contrast, the effects of TNF and PDl58780 on functional differentiation (i.e. casein accumulation) were time-dependent. When measured on day 7 after 48 hours of treatment, casein accumulation was unaffected by either concentration of TNF or by PDl5S7SO. When assessed on day 21 after 16 days of treatment, however, casein levels were decreased by 40 ng/ml TNF and increased by PD158780. Significantly, this PD158780-induced increase in casein was not observed in MEC which had been treated with both PD158780 and TNF. These results thus suggest that EGFR tyrosine kinase activity is not necessary for TNF action in normal MEC.
Descriptors : *ACCUMULATION, *NECROSIS, *MAMMARY GLANDS, *BREAST CANCER, EPITHELIUM, RATS, MORPHOLOGY, NEOPLASMS, CELLS(BIOLOGY), MORPHOGENESIS, CASEIN.
Subject Categories : Anatomy and Physiology
Medicine and Medical Research
Distribution Statement : APPROVED FOR PUBLIC RELEASE