evaluation of human breast adenocarcinoma (mcf-7) cells proliferation in co-culture with human adipocytes in three dimensional collagen gel matrix: norepinephrine as a lipolytic factor

background: norepinephrine plays a trophic role in the control of cell replication and differentiation in target cells that express adrenergic receptors. methods: in this study, we have tested the influence of infraphysiological, physiological and supraphysiological concentrations (0.0001 nm, 1 nm, 10000 nm) of human norepinephrine on the proliferation of breast cancer cells (human breast adenocarcinoma [mcf-7]) in co-culture with human adipocytes in three-dimensional collagen gel matrix culture. cell proliferation and lipolysis rate were measured by 3-(4, 5-dimethylthiazolyl)-2, 5-diphenyl-tetrazolium bromide (mtt) and oil red o colorimetric assay in second, 7th days of culture experiments. results: our results showed a direct correlation between lipolysis rate of adipocytes and proliferation rate of mcf-7 cells. both physiological and supraphysiological concentrations of human norepinephrine significantly (p<0.05) increased the proliferation of mcf-7 cells synchronously with progress of adipocyte lipolysis. the proliferations of mcf-7 cells were significantly decreased after conversion of adipocytes to fibroblast-like cells by supraphysiological concentration of norepinephrine. there was no statistical difference in lipolysis of adipocytes and proliferation of mcf-7 cells in response to infraphysiological concentration of norepinephrine. conclusion: these findings indicated that norepinephrine stimulated the proliferation of mcf-7 cells in coculture with human adipocytes as a lipolytic factor and that norepinephrine effect was suppressed by conversion of adipocytes to fibroblast-like cells, suggesting adipocytes as another target for prevention and therapy of breast cancer.