Consumption of high ω-3 fatty acid diet suppressed prostate tumorigenesis in C3(1) Tag mice

Prostate cancer incidence and mortality are high in the Western world and high omega-6/omega-3 PUFA in the Western diet may be a contributing factor. We investigated whether changing from a diet that approximates omega-6 fat content of the Western diet to a high omega-3 fat diet at adulthood might reduce prostate cancer risk. Female SV 129 mice that had consumed a high omega-6 diet containing corn oil for 2 weeks were bred with homozygous C3(1)Tag transgenic male mice. All male offspring were weaned to the corn oil diet (CO) until postpuberty when half of the male offspring were transferred to a high omega-3 diet containing canola oil and fish oil concentrate (FS). High omega-3 diet increased omega-3 and decreased omega-6 fat content of mice tissues. Average weights of prostate and genitourinary bloc were significantly lower in mice consuming high omega-3 diet at adulthood (CO-FS) than mice fed a lifetime high omega-6 diet (CO-CO). There was slower progression of tumorigenesis in dorsalateral prostate of CO-FS than in CO-CO mice. CO-FS mice had slightly lower plasma testosterone level at 24 and 40 weeks, significantly lower estradiol level at 40 weeks and significantly less expressed androgen receptor (AR) in the dorsalateral prostate at 40 weeks than CO-CO mice. Consumption of high omega-3 diet lowered the expression of genes expected to increase proliferation and decrease apoptosis in dorsalateral prostate. Our results suggest that consumption of high omega-3 diet slows down prostate tumorigenesis by lowering estradiol, testosterone and AR levels, promoting apoptosis and suppressing cell proliferation in C3(1)Tag mice.