Concentration of PUFA can influence EGFR/MAPK signal transduction in human breast cancer cellsˇ
aVA-MD Regional College of Veterinary Medicine, bDepartment of Dairy Science; Virginia Tech, Blacksburg, Virginia, United States
Epidermal Growth Factor Receptor/Mitogen Activated Protein Kinase (EGFR/MAPK) is a cell-surface associated signal transduction cascade suggested to be involved in breast cancer cell development. Cell membrane-incorporated dietary polyunsaturated fatty ac ids (PUFA) may alter the action of the EGFR/MAPK pathway directly or indirectly, to influence cell development and progression. Utilizing two human breast cancer cell lines, we investigated the location and duration, within the EGFR/MAPK pathway, omega-3 (DHA) and omega-6 (LA) influence signal transduction. METHODS: Human breast cancer cell lines (MDA-MB0-231; BT-20) were subjected to various concentrations of DHA:LA (range of 0.01-10) and DHA or LA alone (0-60; 0-58 µg/ml, respectively) in the cell culture media. Cell proliferation using an Alamar Blue technique and MAPK, MEK1/2, and Raf-1 activity, via western immunoblotting, were evaluated. RESULTS: DHA/LA ratio has no effect on cell growth on cell lines tested. A concentration effect on cell g rowth for the MDA-MB-231 cell with DHA and LA, alone, was biphasic (P=0.0023; P=0.003, respectively) and exponential for the BT-20 cell with DHA (P=0.0087). A dose response experiment was done to identify dose and duration of EGF for western immunoblotti ng assays. CONCLUSIONS: The concentration and type of PUFA appear to influence cell growth and activity of MAPK, MAK1/2, and Raf-1 signal pathway intermediates in hormone-sensitive and –insensitive breast tumor cells. Current research utilizes radio-ligand binding techniques to evaluate the relationship of EGFR and PUFA on breast tumor cell growth.
Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Nice, France; February 7 - 10, 2004; in oral session 998 (Signaling pathways - Part III).