Influence of PUFA on a prospective cancer biomarker in feline adipose

KE Sakera , BE Cowinga, JH Herbeinb

VA-MD Regional College of Veterinary Medicinea and Department of Dairy Scienceb, Virginia Tech, Blacksburg, VA.

AIM: Epidermal growth factor/mitogen-activated protein kinase (EGFR/MAPK) pathway is a cell-surface associated signal transduction cascade, suggested to be involved in breast cancer cell development. Cell membrane-incorporated dietary polyunsaturated fatty acids (PUFA) may alter the action of the EGFR/MAPK pathway directly or indirectly influencing cell development and progression. The ability to identify alterations in mammary adipose MAPK based on PUFA tissue concentrations would be benefical as a cancer prognosticator and anti-tumorigenic agent. Previous work indicates MAPK is detectable and responsive to dietary PUFA in the feline which shares similar mammary tumor characteristics with human subjects, therefore we continue to use this animal model to investigate breast cancer. METHODS: Subcutaneous mammary / inguinal adipose tissue was obtained from subjects and immediately stored in liquid nitrogen. Tissue was processed and analyzed for n-6 and n-3 PUFA and active MAPK, respectively. RESULTS: Dietary n-6:n-3 PUFA influenced adipose PUFA concentration. Changes from baseline across all dietary treatments was proportionately reflected in adipose n6:n3 concentrations, with the effect of age evident at the lowest n6:n3 PUFA treatments. Subjects with developing mammary tumors exhibited a significant increase in immune cell MAPK over time that mirrored mammary adipose tissue changes. Results are pending on MAPK for the healthy subject tissue biopsies, but based on preliminary data we expect a positive correlation between tissue MAPK and dietary PUFA. CONCLUSIONS: Adipose tissue MAPK shows promise as a biomarker for breast cancer and may be modulated by dietary PUFA thereby manipulating tumor development through nutrient intervention.

KEY WORDS: Key Words MAPK, mammary tumor, breast cancer, nutrient.

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Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Paris, France; February 9 - 12, 2002; in the section on Predictive Markers.