Proliferative effect of whey from cows’ milk varying in phyto-oestrogens in human breast and prostate cancer cells

Abstract

Intake of dietary phyto-oestrogens has received a great deal of attention owing to their potential influence on hormone-sensitive cancers such as breast and prostate cancer. Cows' milk contains phyto-oestrogens and the content varies according to the composition of the feed and the type and amount of legumes used. In this study we evaluated the proliferative effect of milk (whey) with different phyto-oestrogen content in human breast (MCF-7) and prostate cancer cells (PC-3). Milk was obtained from cows fed either a birdsfoot trefoil-timothy silage based ration (B1) or two different red clover silage based diets (R1 and R2) resulting in total phyto-oestrogen contents of 403, 1659 and 1434 ng/ml for the B1, R1 and R2 diets, respectively. Whey was produced from the milk and added to cell culture medium in concentrations up to 10% for MCF-7 cells and 5% for PC-3 cells. Cell proliferation was measured fluorometrically after 7 d for MCF-7 cells and 5 d for PC-3 cells. There was no significant difference in the proliferative effect of whey from the different dietary treatments at any of the whey concentrations tested. An anti-proliferative effect (P<0·01) of 5 and 10% whey was seen when tested in the presence of 10 pM oestradiol in the medium. This effect was independent of dietary treatment of cows. Whey induced a significant (P<0·01) proliferative response in PC-3 cells independent of dietary treatment. Purified equol in concentrations similar to equol concentrations in milk decreased PC-3 cell proliferation, and therefore the stimulatory effect of whey in PC-3 cells is believed to be mediated by other bioactives than equol. In conclusion, our results suggest that using whey in these proliferation assays, it was not possible to discriminate between milk with high or low levels of phyto-oestrogens.

Profile of phenolic compounds inTrifolium pratenseL. extracts at different growth stages and their biological activities

“…The bioactive compounds have been identified in this plant exhibit health benefits for humans, including antioxidative and antiinflammatory properties. [2,3] These bioactive compounds also occur in a normal diet, in a transformed form, via meat of livestock that feed on clover as well as milk and dairy products. [4] There are several reports on polyphenols with emphasis on isoflavonoid contents.…”

A Milk Protein, Casein, as a Proliferation Promoting Factor in Prostate Cancer Cells

“…Recent studies revealed that milk protein plays a key role in the development and modulation of prostate cancer cell proliferation [16,17,23]. Tate et al [16] reported that cow's milk stimulated the growth of prostate cancer cells (LNCaP) almost as much as digested whole milk.…”

“…Like our results, neither casein nor digested milk increased the growth of breast cancer cells (MCF-7). Nielsen et al [17] evaluated the effect of whey protein, a second fraction of milk protein, on prostate cancer cell (PC-3) growth. While whey had an anti-proliferative effect on breast cancer cells (MCF-7), this protein had a stimulatory effect on prostate cancer cell (PC-3) growth under the control of the estrogen concentration.…”

“…Several cell culture studies showed that milk protein could contribute to cancer prevention. The opposite results have appeared in recent epidemiologic studies [16,17]. The growth of prostate cancer cells was stimulated by milk protein [16,17].…”

“…The opposite results have appeared in recent epidemiologic studies [16,17]. The growth of prostate cancer cells was stimulated by milk protein [16,17]. Owing to these conflicting results, the potential role of milk protein in prostate cancer is still controversial.…”