We are studying the effects of the cytokines IL-1, IL-6 and TNF alone and in combination on cell growth and estradiol stimulated metabolism of breast cancer cells. We found that all three cytokines inhibit cell growth in vitro with the following efficacy: TNF > IL-1 > IL-1. IL-1 downregulates the ER, but does not block estradiol downregulation of the ER or stimulation of PR synthesis. This suggests that the proliferative and metabolic effects of estradiol in these cells are regulated separately. IL-1 stimulates secretion of the inhibitory growth factor TGFbeta in a time and dose dependent manner. Antibodies to TGFbeta block IL-1 inhibition of cell growth, indicating TGFbeta mediates IL-1 action. IL-1 does not alter IGF-1 secretion. TNF increases secretion of biologically active TGFbeta in a time and dose-dependent manner. TNF causes a shift in the isomeric form of TGFbeta secreted from TGFbeta1 to TGFbeta1.2, is acting at the posttranscriptional level, and does not alter the electrophoretic pattern of TGFbeta species in the secretate. TNF blocks estradiol stimulated growth in a dose-dependent manner, and upregulates the PR. The effects on ER mRNA expression and protein concentration are similar to IL-1, providing evidence of overlapping biological activities between these two cytokines, and indicating an important interaction between the immune and endocrine systems. A second important area of study is the establishment of cell lines from solid breast tumors. We have established cell lines from the solid tumors of 19 patients, including 15 primary tumors and 4 metastatic lesions. The cell lines have been characterized morphologically, immunocytologically for keratin staining, expression of DF3 breast carcinoma antigen, and MHC expression. Four cell lines have been stably transfected with a retroviral vector containing the TNF gene,and secrete high levels of TNF protein. Cells are being studied by karyotyping, by in situ hybridization, and by RFLP to identify chromosomal and DNA or mRNA genetic abnormalities. In vivo tumorigenicity determination of these cell lines is in progress. These cell lines can provide an in vitro and in vivo model system to study metabolic regulation of cytokines on breast cancer cells and their effects on genetic abnormalities, including oncogenes, tumor suppressor genes, and MDR genes associated with this type of malignancy.
