Soy and soy products have been a staple in the standard diet in China, Japan, Indonesia and other Asian countries for centuries. Epidemiological studies have shown that the incidences of breast and prostate cancers are much higher in the US and in European countries than in these Asian countries where the consumption of traditional soy based foods such as tofu, tempe, natto, shoyu, soy sauce, miso, is higher. It is believed that the inclusion of a moderate amount of these fermented soy products in the traditional diet of Asian populations play an important role in overall disease prevention and enhancement of well being. Soy based diets are safe and provide powerful health benefits. The isoflavones in soy based diets have been studied extensively and shown to have many therapeutic and preventive properties against different types of cancers.

The role of free radicals in Alzheimer disease pathophysiology has been appreciated for a long time. Originally, radicals were considered as causative of oxidative damage. More recently their role as signalling molecules in this, as well as in other fields of free radical biology, has been underscored. Mitochondria are both generators and targets of radical damage in aging. In this paper we review evidence that radicals generated in mitochondria in the presence of A beta are signals that trigger both the mitochondrial and the extra-mitochondrial pathways of apoptosis. There are gender specific differences in mitochondrial A beta toxicity: mitochondria from young (but not from old) females appear to be protected. 17-beta Estradiol or phytoestrogens like genistein prevent the formation of oxidants by mitochondria and protect against mitochondrial A beta toxicity. Experiments reported here indicate that phytoestrogens might have a role in the prevention of Alzheimer's disease.

Genistein is a plant-derived compound possessing well-known preventive activity in breast and prostate cancer, cardiovascular diseases and post-menopausal problems. Lately, the interests in genistein have widened. The studies concerning effects of genistein performed on animals and humans revealed other aspects of its action -- the metabolic alterations at the cellular level and in the whole organism. It was shown that genistein decreased body and fat tissue weight gains accompanied by reduced food intake. After ingestion of dietary genistein, the alterations in concentrations of hormones such as: insulin, leptin, thyroid hormones, adrenocorticotropic hormone, cortisol and corticosterone were observed. The changes in lipid parameters -- triglycerides and cholesterol were also noticed as a consequence of genistein administration. Moreover, the altered expression of genes engaged in lipid metabolism, disturbed glucose transport into cells, affected lipolysis and lipogenesis and changed ATP synthesis were found as a result of genistein action.

BACKGROUND: New cancer therapeutic strategies must be investigated that enhance prostate cancer treatment while minimizing associated toxicities. We have previously shown that genistein, the major isoflavone found in soy, enhanced prostate cancer radiotherapy in vitro and in vivo. In this study, we investigated the cellular and molecular interaction between genistein and radiation using PC-3 human prostate cancer cells. METHODS: Tumor cell survival and progression was determined by clonogenic analysis, flow cytometry, EMSA analysis of NF-kappaB, and western blot analysis of cyclin B1, p21WAF1/Cip1, and cleaved PARP protein.

RESULTS: Genistein combined with radiation caused greater inhibition in PC-3 colony formation compared to genistein or radiation alone. Treatment sequence of genistein followed by radiation and continuous exposure to genistein showed optimal effect. Cell cycle analysis demonstrated a significant dose- and time-dependent G2/M arrest induced by genistein and radiation that correlated with increased p21WAF1/Cip1 and decreased cyclin B1 expression. NF-kappaB activity was significantly decreased by genistein, yet increased by radiation. Radiation-induced activation of NF-kappaB activity was strongly inhibited by genistein pre-treatment. A significant and striking increase in cleaved PARP protein was measured following combined genistein and radiation treatment, indicating increased apoptosis. CONCLUSION: A mechanism of increased cell death by genistein and radiation is proposed to occur via inhibition of NF-kappaB, leading to altered expression of regulatory cell cycle proteins such as cyclin B and/or p21WAF1/Cip1, thus promoting G2/M arrest and increased radiosensitivity. These findings support the important and novel strategy of combining genistein with radiation for the treatment of prostate cancer.

BACKGROUND: New cancer therapeutic strategies must be investigated that enhance prostate cancer treatment while minimizing associated toxicities. We have previously shown that genistein, the major isoflavone found in soy, enhanced prostate cancer radiotherapy in vitro and in vivo. In this study, we investigated the cellular and molecular interaction between genistein and radiation using PC-3 human prostate cancer cells.

METHODS: Tumor cell survival and progression was determined by clonogenic analysis, flow cytometry, EMSA analysis of NF-kappaB, and western blot analysis of cyclin B1, p21WAF1/Cip1, and cleaved PARP protein.

RESULTS: Genistein combined with radiation caused greater inhibition in PC-3 colony formation compared to genistein or radiation alone. Treatment sequence of genistein followed by radiation and continuous exposure to genistein showed optimal effect. Cell cycle analysis demonstrated a significant dose- and time-dependent G2/M arrest induced by genistein and radiation that correlated with increased p21WAF1/Cip1 and decreased cyclin B1 expression. NF-kappaB activity was significantly decreased by genistein, yet increased by radiation. Radiation-induced activation of NF-kappaB activity was strongly inhibited by genistein pre-treatment. A significant and striking increase in cleaved PARP protein was measured following combined genistein and radiation treatment, indicating increased apoptosis.

CONCLUSION: A mechanism of increased cell death by genistein and radiation is proposed to occur via inhibition of NF-kappaB, leading to altered expression of regulatory cell cycle proteins such as cyclin B and/or p21WAF1/Cip1, thus promoting G2/M arrest and increased radiosensitivity. These findings support the important and novel strategy of combining genistein with radiation for the treatment of prostate cancer.

The incidence of non-Hodgkin's lymphoma (NHL) has been increasing and is now the leading cause of death in males aged 15-54. Diffuse large cell lymphoma (DLCL) is the most common subtype of NHL. These cells are notable for the high expression of the transcription factor nuclear factor kappa beta (NF-kappaB), raising the possibility that constitutive activation of the NF-kappaB pathway may contribute to the poor prognosis of DLCL patients. Soy isoflavone genistein promotes apoptosis by decreasing NF-kappaB activity. The combination of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) remains the standard therapy for DLCL with a cure rate of approximately 40%. The WSU-DLCL(2) cell line and its severe combined immunodeficient (SCID) xenograft have constitutively active NF-kappaB which provides us with an excellent model in which to study NF-kappaB modulation and CHOP sensitization by genistein.

The antitumor activity of CHOP with or without a genistein was evaluated in our WSU-DLCL(2) model. In vivo, WSU-DLCL(2)-bearing SCID mice received genistein alone (800 micro g kg(-1) day(-1), p.o. as gavages for 5 days), CHOP alone ("C", 40 mg/kg, i.v.; "H", 3.3 mg/kg, i.v.; "O", 0.5 mg/kg, i.v.; and "P", 0.2 mg/kg, every day for 5 days, p.o.), or genistein for 5 days followed by CHOP. Tumor growth inhibition (T/C), tumor growth delay (T - C), and log(10) kill for genistein, CHOP, and genistein followed by CHOP were 33.6%, 19.2%, and 5.2%; 7, 8, and 17 days; and 1.0, 1.2, and 2.6, respectively. To begin elucidating the mechanism of genistein-induced sensitization of WSU-DLCL(2) cells to CHOP chemotherapy in this xenograft mouse model, we studied the in vitro effect of genistein on WSU-DLCL(2) growth inhibition, cell cycle, Bax:Bcl-2 ratio, NF-kappaB DNA binding, and apoptosis in vitro. At 30 micro M, genistein inhibited the growth significantly, induced G(2)-M arrest, increased Bax:Bcl-2 ratio, decreased NF-kappaB DNA binding, and induced apoptosis. Genistein also inhibited NF-kappaB DNA binding in vivo, whereas CHOP enhanced it. Our results show that genistein has growth modulatory effects on WSU-DLCL(2) cells and enhances the antitumor activity of CHOP. Because soy isoflavone genistein is a widely available nutritional supplement, its use in combination with CHOP chemotherapy should be further explored in a clinical trial in patients with NHL.

We have previously reported that estrogens up-regulate longevity-associated genes. As recent evidence has shown that estrogen replacement therapy is associated with an increased risk of cardiovascular disease, we have studied the effects of genistein, a soy isoflavone with a similar structure to estradiol, on the expression of antioxidant, longevity-related genes. MCF-7 cells (human mammary gland tumor cell line) were incubated for 48 h with 0.5 microM genistein, a concentration found in the plasma of populations consuming diets rich in soy protein. Peroxide levels were determined by fluorimetry, activation of extracellular-signal regulated kinase (ERK1/2), and nuclear factor kappaB (NFkappaB)-signaling pathways by Western blot analysis and ELISA, respectively, and mRNA expression of antioxidant genes by real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Inhibition of basal peroxide levels in MCF-7 cells by genistein was prevented by pretreatment of cells with the estrogen receptor antagonist tamoxifen. Phosphorylation of extracellular regulated kinase (ERK)1/2 led to an activation of NFkappaB, as indicated by increased p50 subunit expression in nuclear extracts, and increased mRNA levels of the antioxidant enzyme manganese-superoxide dismutase (MnSOD). Inhibition of ERK1/2 abrogated genistein- mediated NFkappaB activation and elevated expression of MnSOD. Our molecular studies may provide a basis to determine the effects of genistein and other soy protein-derived products on longevity in both animals and the human population.

Prostate cancer is the second leading cause of cancer-related deaths in menin the United States. Genistein is a prominent isoflavonoid found in soy products and has been proposed to be responsible for lowering the rate of prostate cancer in Asians. However, the molecular mechanism(s) by which genistein elicits its effects on prostate cancer cells has not been fully elucidated. We have previously shown that genistein induces apoptosis and inhibits the activation of nuclear factor kappaB (NF-kappaB) pathway, which could be mediated via Akt signaling pathway, the most important survival pathway in cellular signaling. In this study, we investigated whether there is any cross-talk between Akt and NF-kappaB during genistein-induced apoptosis in PC3 prostate cancer cells. We found that genistein inhibits cell growth and induces apoptotic processes in PC3 prostate cancer cells but not in nontumorigenic CRL-2221 human prostate epithelial cells. Immunoprecipitation, kinase assays, and Western blot analysis showed that genistein specifically inhibits Akt kinase activity and abrogates the epidermal growth factor-induced activation of Akt in prostate cancer cells. NF-kappaB DNA-binding analysis and transfection studies with Akt cDNA and NF-kappaB-Luc constructs revealed that Akt transfection results in the induction of NF-kappaB activation and this is completely inhibited by genistein treatment. Moreover, genistein abrogated the epidermal growth factor-induced activation of NF-kappaB, which was mediated via Akt signaling pathway. From these results, we conclude that the inhibition of Akt and NF-kappaB activity and their cross-talk provide a novel mechanism by which genistein inhibits cell growth and induces apoptotic processes in tumorigenic but not in nontumorigenic prostate epithelial cells.

Findings with experimental rodent models reveal that exposures to dietary factors during the in utero and pubertal periods when the mammary gland is undergoing extensive modeling and re-modeling, alter susceptibility to develop mammary tumors. Similar observations have been made in humans: childhood exposure to genistein in soy or to some other bioactive food components reduces later breast cancer risk, although they may have no effect if consumed during adulthood. Thus, food components may be more effective in affecting cancer risk in some periods of life than others. Many of these dietary exposures modify fetal and postnatal hormonal environment, including changing the concentrations of estrogens and leptin. The hormonal alterations then may induce persistent epigenetic changes by affecting gene promoter regions or by inducing histone modifications that affect chromatin transcription. The targets of epigenetic changes are likely to be the terminal end buds (TEBs), the structures where carcinogen-induced mammary tumors in rats and mice are initiated. More specifically, the site of these changes in TEBs may be the stem cells and their niche; this might explain how an exposure early in life affects the risk of breast cancer decades later. Similar structures in women, called terminal ductal lobular units, are the sites where most human breast cancers rise. According to this hypothetical model, cancer is initiated only when the epigenetically altered cells are exposed to carcinogens/radiation, etc. during adult life. In a "normal" stem cell or its niche, cancer initiating exposures do not necessarily cause cancer, because the cells can either repair the damage or undergo apoptosis. Thus, the most likely molecular targets of early life dietary exposures are genes that regulate DNA adduct formation, repair DNA damage or induce apoptosis, such as genes affecting cellular metabolism, tumor suppressor genes or genes promoting cell survival. It is possible that some of these epigenetic changes also explain why the number of TEBs generally, but not always, correlates with breast cancer risk. This hypothesis may imply that adult intake of some bioactive dietary components reduces cancer risk increased by early life dietary exposures or inhibits tumor growth by reversing epigenetic changes in various molecular targets.

The epidermal growth factor receptor (EGFR) is a target of new therapies in most nonhematologic cancers. EGFR blockade alone may not be sufficient for the control of growth and invasion of human pancreas cancer because of the independent activation of Akt and nuclear factor-kappaB (NF-kappaB). The expression of EGFR, Akt, and NF-kappaB was determined in six human pancreatic cancer cell lines. Selected cells for specific expression were treated with erlotinib, genistein, gemcitabine, or the combination. Growth inhibition was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and apoptosis was assayed by ELISA. EGFR, phosphorylated EGFR, phosphorylated Akt, and surviving expressions were determined by immunoblotting.

Electrophoretic mobility shift assay was used to evaluate the DNA binding activity of NF-kappaB. Genistein significantly increased (P < 0.05) erlotinib-induced growth inhibition and apoptosis in BxPC-3, CAPAN-2, and AsPC-1 cells. In the BxPC-3 cell line, significant down-regulation of EGFR, phosphorylated Akt, NF-kappaB activation, and survivin was observed in the cells treated with the combination compared with the erlotinib-treated cells. In the HPAC and MIAPaCa cell line, no potentiation of the effects of erlotinib by genistein on cell growth or inhibition of the EGFR/Akt/NF-kappaB was observed. Genistein potentiated growth inhibition and apoptosis of the gemcitabine and erlotinib combination in COLO-357 cell line. Genistein potentiates the growth inhibition and apoptosis induced by erlotinib and gemcitabine in certain pancreatic cancer cells. Akt and NF-kappaB inhibition represents one of the mechanisms for the potentiation of erlotinib- and gemcitabine-induced cell death by genistein.

Dietary habits and incidence of prostate cancer (PCa) are very different in several parts of the world. Among the differences between Eastern and Western diets is the greater intake of soy in the Eastern cultures. This might be one factor contributing to a lower incidence of PCa in Asian men. Many studies using PCa cells and animal studies of chemical carcinogenesis have shown that a wide range of dietary compounds have cancer chemopreventive potential. Therefore, the interest in nutrition-based approaches for prevention and treatment of PCa is increasing. We reviewed all experimental preclinical in vitro and in vivo data as well as clinical trials performed with soy isoflavone genistein for prevention and treatment of PCa.

The preclinical data for genistein presented in this review show a remarkable efficacy against PCa cells in vitro with molecular targetsranging from cell cycle regulation to induction of apoptosis. In addition, seemingly well-conducted animal experiments support the belief that genistein might have a clinical activity in human cancer therapy. However, it is difficult to make definite statements or conclusions on clinical efficacy of genistein because of the great variability and differences of the study designs, small patient numbers, short treatment duration and lack of a standardized drug formulation. Although some results from these genistein studies seem encouraging, reliable or long-term data on tumor recurrence, disease progression and survival are unknown. The presented data potentially allow recommending patients the use of genistein as in soy products in a preventive setting. However, at present there is no convincing clinical proof or evidence that genistein might be useful.

Interleukin-6 is a pleiotropic cytokine which plays a crucial role in immune physiology and is tightly controlled by hormonal feedback mechanisms. After menopause or andropause, loss of the normally inhibiting sex steroids (estrogen, testosterone) results in elevated IL6 levels that are further progressively increasing with age. Interestingly, excessive IL6 production promotes tumorigenesis (breast, prostate, lung, colon, ovarian), and accounts for several disease-associated pathologies and phenotypical changes of advanced age, such as osteoporosis, rheumatoid arthritis, multiple myeloma, neurodegenerative diseases and frailty. In this respect, pharmacological modulation of IL6 gene expression levels may have therapeutical benefit in preventing cancer progression, ageing discomforts and restoring immune homeostasis. Although "plant extracts" are used in folk medicine within living memory, it is only since the 20th century that numerous scientific investigations have been performed to discover potential health-protective food compounds or "nutraceuticals" which might prevent cancer and ageing diseases.

About 2000 years ago, Hippocrates already highlighted "Let food be your medicine and medicine be your food". Various nutrients in the diet play a crucial role in maintaining an "optimal" immune response, such that deficient or excessive intakes can have negative consequences on the organism's immune status and susceptibility to a variety of pathologies. Over the last few decades, various immune-modulating nutrients have been identified, which interfere with IL6 gene expression. Currently, a broad range of phyto-pharmaceuticals with a claimed hormonal activity, called "phyto-estrogens", is recommended for prevention of various diseases related to a disturbed hormonal balance (i.e. menopausal ailments and/or prostate/breast cancer). In this respect, there is a renewed interest in soy isoflavones (genistein, daidzein, biochanin) as potential superior alternatives to the synthetic selective estrogen receptor modulators (SERMs), which are currently applied in hormone replacement therapy (HRT). As phyto-chemicals integrate hormonal ligand activities and interference with signaling cascades, therapeutic use may not be restricted to hormonal ailments only, but may have applications in cancer chemoprevention and/or NF-kappaB-related inflammatory disorders as well.

Dietary intake of soy has been associated with a decreased risk of cancer. Soy isoflavones have been postulated to be the protective compounds in soybeans; however, the precise mechanism by which soy isoflavones prevent human cancer is not known. The major soy isoflavones, genistein and daidzein, are antioxidant compounds, therefore one possible mechanism of action is through their antioxidant effect. We have previously demonstrated that the soy isoflavone, genistein, inhibits the activation of the redox-sensitive transcription factor, NF-kappa B, in prostate cancer cells in vitro. In this study, we have demonstrated that genistein, but not daidzein, inhibits TNF-alpha-induced NF-kappa B activation in cultured human lymphocytes.

Additionally, we investigated the in vivo effect of soy isoflavone supplementation on NF-kappa B activation induced by TNF-alpha in vitro in peripheral blood lymphocytes of six healthy men. We show that healthy male subjects receiving 50 mg isoflavone mixture (Novasoy) twice daily for 3 weeks are protected from TNF-alpha induced NF-kappa B activation. Additionally, we observed a reduction of 5-hydroxymethyl-2'-deoxyuridine (5-OHmdU), a marker for oxidative DNA damage, following isoflavone supplementation. The inhibitory effect of soy isoflavones was no longer present 3 months after the supplementation. This preliminary study demonstrates that soy isoflavone supplementation may protect cells from oxidative stress-inducing agents by inhibiting NF-kappa B activation and decreasing DNA adduct level.

Epidemiological studies have shown a significant difference in cancer incidence among different ethnic groups, which is believed to be partly attributed to dietary habits. The incidences of breast and prostate cancers are much higher in the United States and European countries compared with Asian countries such as Japan and China. One of the major differences in diet between these populations is that the Japanese and the Chinese consume a traditional diet high in soy products. Soy isoflavones have been identified as dietary components having an important role in reducing the incidence of breast and prostate cancers. Genistein, the predominant isoflavones found in soy, has been shown to inhibit the carcinogenesis in animal models.

There are growing body of experimental evidence that show the inhibition of human cancer cells by genistein through the modulation of genes that are related to the control of cell cycle and apoptosis. Moreover, it has been shown that genistein inhibits the activation of NF-kappa B and Akt signaling pathways, both of which are known to maintain a homeostatic balance between cell survival and apoptosis. Genistein is commonly known as phytoestrogen, which targets estrogen- and androgen-mediated signaling pathways in the processes of carcinogenesis. Furthermore, genistein has been found to have antioxidant property, 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 reagent for cancer chemoprevention and/or treatment. In this article, we attempt to provide evidence for these effects of genistein in a succinct manner to provide comprehensive state-of-the-art knowledge of the biological and molecular effects of the isoflavone genistein in cancer cells.

High consumption of soy products in some Asian countries has been linked to the low incidence of breast cancer in women. The chemopreventive effect of the soy isoflavone, genistein, has been observed through the suppression of cell proliferation, inhibition of angiogenesis and stimulation of apoptosis in breast carcinoma cells. Cancer metastasis consists of interdependent processes, including cell adhesion, migration and invasion.

In the present study, we compare the effect of soy isoflavones in the form of aglycones (genistein, daidzein and glycitein) and glucosides (genistin, daidzin and glycitin) on the behavior of highly invasive breast cancer cells. Here we demonstrate that genistein suppresses cell adhesion and migration by inhibiting the constitutively active transcription factors NF-kappaB and AP-1, resulting in the suppression of secretion of urokinase-type plasminogen activator (uPA) in breast cancer cells MDA-MB-231. In addition, we show that all tested soy isoflavone aglycones (genistein, daidzein, glycitein) and glucosides (genistin, daidzin, glycitin) markedly reduced motility of MDA-MB-231 cells. However, only genistein and daidzein inhibited constitutively active NF-kappaB and AP-1 and suppressed secretion of uPA from breast cancer cells. Taken together, our results suggest that dietary soy isoflavones inhibit adhesion and motility of highly invasive breast cancer cells by distinct signaling pathways.

A role of dietary bioactive components in bladder cancer prevention is biologically plausible because most substances or metabolites are excreted through the urinary tract and are consequently in direct contact with the mucosa of the bladder. We first determined antigrowth activity of genistein against poorly differentiated 253J B-V human bladder cancer cells in vitro. Genistein inhibited the cell growth in a time- and dose-depen dent manner via G(2)-M arrest,down-regulation of nuclear factor kappaB (NF-kappaB), and induction of apoptosis. We also evaluated both genistin, which is a natural form of genistein, and the isoflavone-rich soy phytochemical concentrate (SPC) on the growth and metastasis of 253J B-V tumors in an orthotopic tumor model. Mice treated with genistin and SPC had reduced final tumor weights by 56% (P < 0.05) and 52% (P < 0.05), respectively, associated with induction of tumor cell apoptosis and inhibition of tumor angiogenesis in vivo. In addition, SPC treatment, but not genistin treatment, significantly inhibited lung metastases by 95% (P < 0.01) associated with significant down-regulation of NF-kappaB expression in tumor tissues and reduction of circulating insulin-like growth factor-I levels, suggesting that SPC may contain other bioactive ingredients that have antimetastatic activity. The results from our studies suggest that further clinical investigation should be warranted to apply soy phytochemicals, such as SPC, as a potent prevention regimen for bladder cancer progression. This orthotopic human bladder tumor model also provides a clinically relevant experimental tool for assessing potential preventive activity of other dietary components against bladder tumor growth and metastasis.

Bone metastasis is very common in advanced prostate cancer. Docetaxel has been shown to improve survival in patients with metastatic prostate cancer. However, treatment with docetaxel is associated with a certain degree of toxicity. Genistein, derived from soybeans, has been found to inhibit cancer cell growth without toxicity. We have recently reported that genistein could potentiate the antitumor activity of chemotherapeutic agents both in vitro and in vivo. However, the molecular mechanism of this novel effect of genistein has not been fully elucidated. In this study, we found that genistein significantly potentiated the antitumor, anti-invasive, and antimetastatic activities of docetaxel both in culture and in severe combined immunodeficient (SCID)-human model of experimental prostate cancer bone metastasis. We further conducted microarray analysis, real-time reverse transcription-PCR.

Western blot analysis, small interfering RNA and cDNA transfection, matrix metalloproteinase-9 (MMP-9) activity assay, and invasion assay. We found that the expression of osteoprotegerin (OPG) was induced by genistein and inhibited by docetaxel, whereas genistein significantly down-regulated the expression and secretion of receptor activator of nuclear factor-kappaB (RANK) ligand (RANKL) and inhibited osteoclast formation. Moreover, genistein down-regulated the expression and activity of MMP-9, which was induced by docetaxel treatment, and inhibited invasion of PC-3 cells. These results suggest that the observed potentiation of antitumor activity of docetaxel by genistein in the SCID-human model of experimental bone metastasis could be mediated by regulation of OPG/RANK/RANKL/MMP-9 signaling, resulting in the inhibition of osteoclastic bone resorption and prostate cancer bone metastasis. From these results, we conclude that genistein could be a promising nontoxic agent to improve the treatment outcome of metastatic prostate cancer with docetaxel.