Research Library
Decreased growth of human prostate LNCaP tumors in SCID mice fed a low-fat, soy protein diet with isoflavones.
Authors: Aronson WJ; Tymchuk CN; Elashoff RM; McBride WH McLean C; Wang H; Heber D
Source: Nutr Cancer 1999;35(2):130-6
Epidemiological studies suggest that high intake of dietary fat is a
risk factor for the development of clinical prostate cancer. Soy
protein has also been proposed to play a role in the prevention of
prostate cancer, and one of the isoflavones in soy protein,
genistein, inhibits the growth of human prostate cancer cell lines in
vitro. This study was designed to evaluate whether altering dietary
fat, soy protein, and isoflavone content affects the growth rate of a
human androgen-sensitive prostate cancer cell line (LNCaP) grown in
severe-combined immunodeficient (SCID) mice. SCID mice were
randomized into four dietary groups: high-fat (42.0 kcal%) + casein,
high-fat (42.0 kcal%) + soy protein + isoflavone extract, low-fat
(12.0 kcal%) + casein, and low-fat (12.0 kcal%) + soy protein +
isoflavone extract. After two weeks on these diets, the mice were
injected subcutaneously with 1 x 10(5) LNCaP tumor cells and placed
in separate cages (1 mouse/cage) to strictly control caloric intake.
Isocaloric diets were given 3 days/wk, and tumor sizes were measured
once per week. The tumor growth rates were slightly reduced in the
group that received the low-fat + soy protein + isoflavone extract
diet compared with the other groups combined (p < 0.05). In
addition, the final tumor weights were reduced by 15% in the group
that received the low-fat + soy protein + isoflavone extract diet
compared with the other groups combined (p < 0.05). In this
xenograft model for prostate cancer, there were statistically
significant effects on tumor growth rate and final tumor weight
attributable to a low-fat + soy protein + isoflavone extract diet.