Omega 6/3 Ratio & Prostate Cancer

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Our latest study... (on rats)

http://clincancerres.aacrjournals.org/cgi/content/abstract/12/15/4662

Clinical Cancer Research Vol. 12, 4662-4670, August 1,

2006 © 2006 American Association for Cancer Research

Effect of Altering Dietary -6/-3 Fatty Acid Ratios on

Prostate Cancer Membrane Composition,

Cyclooxygenase-2, and Prostaglandin E2 Naoko

Kobayashi1, R. Barnard6,et al

Purpose: To determine whether altering the dietary

content of -6 (n-6) and -3 (n-3) polyunsaturated fatty

acids affects the growth of androgen-sensitive

prostate cancer xenografts, tumor membrane fatty acid

composition, and tumor cyclooxygenase-2 and

prostaglandin E2 (PGE2) levels.

Experimental Design: Individually caged male severe

combined immunodeficiency mice were fed isocaloric 20%

kcal fat diets with the fat derived either primarily

from n-6 fatty acids (n-6 group) or with the fat

consisting of n-6 and n-3 fatty acids in a ratio of

1:1 (n-3 group), and injected s.c. with Los Angeles

Prostate Cancer 4 (LAPC-4) cells. Tumor volumes and

mouse weights were measured weekly, caloric intake was

measured 3 days per week, and tumors and serum were

harvested at 8 weeks postinjection.

Results: Tumor growth rates, final tumor volumes, and

serum prostate-specific antigen levels were reduced in

the n-3 group relative to the n-6 group. The n-3 group

tumors had decreased proliferation (Ki67 staining) and

increased apoptosis (terminal nucleotidyl

transferase–mediated nick end labeling staining). In

vitro proliferation of LAPC-4 cells in medium

containing n-3 group serum was reduced by 22% relative

to LAPC-4 cells cultured in medium containing serum

from the n-6 group. The n-6/n-3 fatty acid ratios in

serum and tumor membranes were lower in the n-3 group

relative to the n-6 group. In addition, n-3 group

tumors had decreased cyclooxygenase-2 protein and mRNA

levels, an 83% reduction in PGE2 levels, and decreased

vascular endothelial growth factor expression.

Conclusion: These results provide a sound basis for

clinical trials evaluating the effect of dietary n-3

fatty acids from fish oil on tumor PGE2 and membrane

fatty acid composition, and serum and tumor biomarkers

of progression in men with prostate cancer.