Effects of a Soybean Isoflavone Mixture on Carcinogenesis in Prostate and Seminal Vesicles of F344 Rats

Onozawa, Mizuki; Kawamori, Toshihiko; Baba, M.; Fukuda, Kazunori; Toda, Toshiya; Sato, Hidetaka; Ohtani, Mikinobu; Akaza, Hideyuki; Sügimura, Takashi; Wakabayashi, Keiji

doi:10.1111/j.1349-7006.1999.tb00760.x

Cited by 80 publications

(43 citation statements)

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“…Growth inhibition and induction of apoptosis of prostate cancer cells by isoflavones were indicated in several experimental reports. [16][17][18][19][20][21][22][23][24][25] Tofu and natto are rich in isoflavones (tofu 509 µg/g and natto 1273 µg/g 26) ). In fact, Japanese have higher phytoestrogen concentrations in serum than men and women of Western countries (for example, the mean concentration of genistein in phytoestrogen in Japanese men is 492.7 nmol/liter, compared with 33.2 nmol/liter in men from the UK), 27) and have very high urinary excretion of phytoestrogens.…”

Section: Discussionmentioning

confidence: 99%

A case‐control study of diet and prostate cancer in Japan: possible protective effect of traditional Japanese diet

et al. 2004

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The age-adjusted incidence of prostate cancer is low in Japan, and it has been suggested that the traditional Japanese diet, which includes many soy products, plays a preventive role against prostate cancer. We performed a case-control study on dietary factors and prostate cancer in order to assess the hypothesis that the traditional Japanese diet reduces the risk of prostate cancer. Four geographical areas (Ibaraki, Fukuoka, Nara, and Hokkaido) of Japan were selected for the survey. Average daily intake of food from 5 years before the diagnosis was measured by means of a semi-quantitative food frequency questionnaire. We studied 140 cases and 140 individually age ( ± ± ± ±5 years)-matched hospital controls for analysis. Estimates of age-adjusted odds ratios (ORs) and linear trends were calculated by conditional logistic regression models with adjustment for cigarette smoking and total energy intake as confounding factors. Consumption of fish, all soybean products, tofu (bean curds), and natto (fermented soybeans) was associated with decreased risk. ORs of the fourth vs. first quartile and 95% confidence intervals (95%CIs) were 0.45 (0.20-1.02) for fish, 0.53 (0.24-1.14) for all soybean products, 0.47 (0.20-1.08) for tofu, and 0.25 (0.05-1.24) for natto. Consumption of fish and natto showed significantly decreasing linear trends for risk (P < < < <0.05). Consumption of meat was significantly associated with increased risk (the OR of the second vs. first quartile was 2.19, 95%CI 1.00-4.81). Consumption of milk, fruits, all vegetables, green-yellow vegetables, and tomatoes showed no association. Our results provide support to the hypothesis that the traditional Japanese diet, which is rich in soybean products and fish, might be protective against prostate cancer. (Cancer Sci 2004; 95: 238-242) he age-standardized incidence of prostate cancer is low in Japan (10.0 per 100,000), being approximately one-tenth of that in the United States.1) Among Japanese immigrant in Hawaii, age-standardized incidence of prostate cancer is approximately ten times that in Japan.2) It is suggested that environmental factors such as dietary habits play a major role in causation of prostate cancer. A number of case-control studies have indicated that high intake of fat, especially saturated fat, increases the risk of prostate cancer.3) In contrast, high intake of isoflavone, which is mainly found in soybeans and soy products, may reduce the risk of prostate cancer. 4,5) The traditional Japanese diet which includes many soy products is richer in isoflavone, 6,7) and contains less fat than the Western diet. However, an epidemiological study of prostate cancer in Kyoto in 1988 8) yielded no evidence that fat or soybeans were associated with the risk of prostate cancer.Recently in Japan, the incidence rate of prostate cancer has been increasing cocomitantly with the westernization of dietary habits. We carried out a case-control study on dietary factors and prostate cancer to assess the hypothesis that the traditional Japanese diet reduc...

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Section: Discussionmentioning

confidence: 99%

A case‐control study of diet and prostate cancer in Japan: possible protective effect of traditional Japanese diet

et al. 2004

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“…One of the early studies revealed that soy-containing diets reduced the severity of prostatitis in rats [90]. Soy isoflavone supplemented diets also prevented the development of adenocarcinomas in the prostate and seminal vesicles in a rat carcinogenesis model [91]. It has also been reported to be effective in chemical carcinogen-induced rat ovarian carcinogenesis [92].…”

Section: Inhibition Of Cancers In Animalmentioning

confidence: 99%

Multi-targeted therapy of cancer by genistein

Banerjee¹,

Li²,

Wang³

et al. 2008

Cancer Letters

552

383

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Soy isoflavones have been identified as dietary components having an important role in reducing the incidence of breast and prostate cancers in Asian countries. Genistein, the predominant isoflavone found in soy products, has been shown to inhibit the carcinogenesis in animal models. There is a growing body of experimental evidence showing that the inhibition of human cancer cell growth by genisteinis mediated via the modulation of genes that are related to the control of cell cycle and apoptosis. It has been shown that genistein inhibits the activation of NF-κB and Akt signaling pathways, both of which are known to maintain a homeostatic balance between cell survival and apoptosis. Moreover, genistein antagonizes estrogen-and androgen-mediated signaling pathways in the processes of carcinogenesis. Furthermore, genistein has been found to have antioxidant properties, and shown to be a potent inhibitor of angiogenesis and metastasis. Taken together, both in vivo and in vitro studies have clearly shown that genistein, one of the major soy isoflavones, is a promising agent for cancer chemoprevention and further suggest that it could be an adjunct to cancer therapy by virtue of its effects on reversing radioresistance and chemoresistance. In this review, we attempt to provide evidence for these preventive and therapeutic effects of genistein in a succinct manner highlighting comprehensive state-of-the-art knowledge regarding its multi-targeted biological and molecular effects in cancer cells.

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“…5) Animal studies have shown that these two isoflavones inhibit carcinogen-induced tumors of mammary glands 6,7) and skin. 8) Recently, Onozawa et al 9) reported that a soybean isoflavone mixture consisting of 74% genistein and 21% daidzein suppressed the development of invasive carcinomas of the rat prostate/seminal vesicles.…”

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Suppressive Effects of Dietary Genistin and Daidzin on Rat Prostate Carcinogenesis

Kato

Takahashi

Chen

et al. 2000

Japanese Journal of Cancer Research

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High intake of phytoestrogens through soybeans and their products is thought to be associated with low incidences of prostate and/or breast cancer in Asian countries. Possible chemopreventive effects of genistin or daidzin on rat prostate carcinogenesis were therefore investigated. Male F344 rats were given 10 biweekly subcutaneous injections of 3,2′ ′ ′ ′-dimethyl-4-aminobiphenyl (DMAB) and then either genistin or daidzin in the diet at a concentration of 0.1% for 40 weeks. Other groups of rats given DMAB were treated with genistin or daidzin together with a high dose of testosterone propionate (TP). Both genistin and daidzin reduced the numbers of ventral prostate carcinomas (P < < < <0.05), with a tendency for decrease in incidence. Invasive carcinomas which developed in the anterior prostate and seminal vesicles with TP were, however, not influenced by the two isoflavones. Thus, the present data suggest that genistin and daidzin possess anti-cancer effects at relatively early stages of prostate cancer development, providing experimental support for epidemiological findings. Key words: Rats -DMAB -Prostate carcinogenesis -Genistin -DaidzinWhile prostate cancer is the most common internal neoplasm and the second leading cause of cancer death in men in the United States, 1) mortality in Japan from this cause is only two-ninths of that in the United States. 2)Intake of large amounts of soybeans and their products rich in isoflavones, such as genistin and daidzin, is believed to play a role in this difference.3) The daily consumption of isoflavones in the diet by Japanese people is estimated to be approximately 18 mg, 4) and geometric mean plasma individual isoflavonoid concentrations are 7 to 110 times higher in Japanese than in Finnish men. 5)Animal studies have shown that these two isoflavones inhibit carcinogen-induced tumors of mammary glands 6,7) and skin. 8) Recently, Onozawa et al. 9) reported that a soybean isoflavone mixture consisting of 74% genistein and 21% daidzein suppressed the development of invasive carcinomas of the rat prostate/seminal vesicles.In vitro studies have revealed that genistein is an inhibitor of protein tyrosine kinase, which modulates several cellular activities and plays an important role in cell proliferation and cell transformation, 10,11) and also inhibits mammalian DNA topoisomerase II 12) as well as angiogenesis. 13)Genistein and daidzein both have a heterocyclic phenol structure that closely resembles estrogens and enables them to bind to estrogen receptors and to exert weak estrogenic activities. 14-17) Normally soybeans and their products contain glycosides of the isoflavones, genistin and daidzin, and these are deglycosylated by intestinal β-glucuronidase to afford the active forms, genistein and daidzein. We have established an animal model of prostate cancer using 3,2′-dimethyl-4-aminobiphenyl (DMAB). 18,19) This carcinogen induces non-invasive prostate adenocarcinomas limited to the ventral lobe, but invasive and metastasizing adenocarcinomas originating from the d...

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Effects of a Soybean Isoflavone Mixture on Carcinogenesis in Prostate and Seminal Vesicles of F344 Rats

Cited by 80 publications

References 24 publications

A case‐control study of diet and prostate cancer in Japan: possible protective effect of traditional Japanese diet

A case‐control study of diet and prostate cancer in Japan: possible protective effect of traditional Japanese diet

Multi-targeted therapy of cancer by genistein

Suppressive Effects of Dietary Genistin and Daidzin on Rat Prostate Carcinogenesis

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