ABSTRACT: Isoflavones in soy flour diet have different effects on whole-genome expression patterns than purified isoflavone mix in human MCF-7 breast tumors in ovariectomized athymic nude mice
Project description:Scope: Soy flour diet (MS) prevented isoflavones from stimulating MCF-7 tumor growth in athymic nude mice, indicating that other bioactive compounds in soy can negate the estrogenic properties of isoflavones. The underlying signal transduction pathways to explain the protective effects of soy flour consumption were studied here. Methods and results: Ovariectomized athymic nude mice inoculated with MCF-7 human breast cancer cells were fed either MS or purified isoflavone mix (MI), both with equivalent amounts of genistein. Positive controls received estradiol pellets and negative controls received sham pellets. GeneChip-Human-Genome-U133 Plus-2.0 Array platform was used to evaluate gene expressions, and results were analyzed using bioinformatics approaches. Tumors in MS-fed mice exhibited higher expression of tumor-growth-suppressing genes ATP2A3 and BLNK, and lower expression of oncogene MYC. Tumors in MI-fed mice expressed higher level of oncogene MYB and lower level of MHC-I and MHC-II, allowing tumor cells to escape immunosurveillance. MS-induced gene expression alterations were predictive of prolonged survival among estrogen-receptor-positive breast cancer patients, whilst MI-induced gene changes were predictive of shortened survival. Conclusion: Our findings suggest dietary soy flour affects gene expression differently than purified isoflavones, which may explain why soy foods prevent isoflavones-induced stimulation of MCF-7 tumor growth in athymic nude mice.
Project description:We generated DNA microarray based gene expression profiles from three estrogen receptor a (ERa) positive breast cancer cell lines stimulated by 17ß-estradiol (E2) in vitro over a time course, as well as from MCF-7 cells grown as xenografts in ovariectomized athymic nude mice with E2 supplementation and after its withdrawal. Keywords: Cell line and xenograft comparisons
Project description:The effects of freeze-dried tofu, a traditional Japanese soy food, were compared with those of major active soy components, protein and isoflavone, by observing physiological differences and global transcriptomes in the liver of male rats. The GeneChip data was normalized and summarized by using SuperNORM data service (Skylight Biotech Inc.). Significance of expressional change among groups was tested by 2-way ANOVA on the normalized CEL data, which was deposited in a tab-separated ASCII text format. Principal components were identified on the summarized gene data. Rats were randomly divided into 6 groups of 5 samples and assigned experimental diets for 14 days. The experimental diets were as follows: casein diet (C); C containing isoflavone (CI) soy protein diet (S); S containing isoflavone (SI); a diet containing 100 g/kg each of protein derived from casein and freeze-dried tofu (T10); a diet containing 200 g/kg of protein derived from freeze-dried tofu (T20). CI and SI were supplemented with a mixture of isoflavones to match the isoflavone level of T20.
Project description:Soy foods have been suggested to have both positive health benefits and potentially adverse effects largely as a result of their content of isoflavone phytoestrogens. Since soy protein isolate (SPI) contains isoflavones, in addition to purported health benefits, safety concerns have been raised regarding the use of SPI and soy formulas, because of potential estrogenic actions during the neonatal period, including the potential for reproductive toxicity, infertility, and the possibility of increased risk for development and recurrence of estrogen sensitive cancers such as breast cancer. In the current study, we used a rat model to compare the effects of SPI with those of 17b-estradiol (E2), on global gene expression profiles and morphology in the female rat mammary gland. Rats were either fed AIN-93G diets containing casein (CAS) or SPI beginning on postnatal day (PND) 30. Rats were ovariectomized (OVX) on PND 50 and treated with E2 or vehicle for 14 days. Microarray analysis was carried out to compare the effects of SPI and E2 alone or in combination on the mammary gene expression. The data suggest a non-estrogenic effect of SPI on the rat mammary even in the absence of endogenous estrogens.
Project description:We generated DNA microarray based gene expression profiles from three estrogen receptor a (ERa) positive breast cancer cell lines stimulated by 17Ã?-estradiol (E2) in vitro over a time course, as well as from MCF-7 cells grown as xenografts in ovariectomized athymic nude mice with E2 supplementation and after its withdrawal. Experiment Overall Design: 8 MCF-7 xenograft profiles (4 with E2,4 without E2), 14 T47D profiles (with E2 treatment in culture from 0 to 24 hr), 10 BT-474 profiles (with E2 treatment from 0 to 24 hr), 12 MCf-7 profiles (with E2 treatment from 0 to 24 hr)
Project description:Soy foods have been suggested to have both positive health benefits and potentially adverse effects largely as a result of their content of isoflavone phytoestrogens. Since soy protein isolate (SPI) contains isoflavones, in addition to purported health benefits, safety concerns have been raised regarding the use of SPI and soy formulas, because of potential estrogenic actions during the neonatal period, including the potential for reproductive toxicity, infertility, and the possibility of increased risk for development and recurrence of estrogen sensitive cancers such as breast cancer. In the current study, we used a rat model to compare the effects of SPI with those of 17b-estradiol (E2), on global gene expression profiles and morphology in the female rat mammary gland. Rats were either fed AIN-93G diets containing casein (CAS) or SPI beginning on postnatal day (PND) 30.
Project description:In order to help determine the genes involved in resistance of breast cancer to endocrine therapy, we compared global gene expression profiles of tamoxifen-resistant MCF-7 WT xenograft tumors with E2-supplemented tumors. Experiment Overall Design: MCF7 xenografts were established in ovariectomized five to six week-old nu/nu athymic nude mice supplemented with 0.25 mg 21 day release estrogen pellets by inoculating subcutaneously (s.c.) 5E-6 cells. When tumors reached the size of 150-200 mm3 (3-5 weeks), the animals were randomly allocated to continued estrogen (E2) and estrogen withdrawal plus tamoxifen citrate. Tumors were harvested for molecular studies when they became resistant to treatment and reached the size of 1000 mm3 (n=7).
Project description:Soyfoods have been drawn the interrest in the roles that reducing risk of cardiovascular disease. Among various components, isoflavones have been come to the attention as beneficial soy ingredients. To evaluate the effectiveness of isoflavone content in dietary soybean (Glycine max) on modulating lipid metabolism, hepatic gene expressions involved in lipid metabolism were analyzed in rats. An isoflavone-rich cultivar (Yukipirika) and a conventional cultivar (Fukuyutaka) were employed. A principal component analysis (PCA) of microarray data was used to summarize characteristics of the experimental groups. As a result, the characteristics of the diets were largely explained by the first principal component (PC1). Soybean content in the diets distinctly separated in PC1. In contrast, isoflavone content had little effect on the mRNA expression. The GeneChip data was normalized and summarized by using SuperNORM data service (Skylight Biotech Inc.). Significance of expressional change among groups was tested by 2-way ANOVA on the normalized CEL data, which was deposited in a tab-separated ASCII text format. Principal components were identified on the summarized gene data.
Project description:Effects of soy isoflavones, genistein and daidzein, on the hepatic gene expression profile and indices for lipid metabolism were compared in rats. The GeneChip data was normalized and summarized by using SuperNORM data service (Skylight Biotech Inc.). Significance of expressional change among groups was tested by 2-way ANOVA on the normalized CEL data, which was deposited in a tab-separated ASCII text format. Principal components were identified on the summarized gene data. Three groups of rats were fed with an experimental diet containing 2 g/kg of either genistein or daidzein, or a control diet free of isoflavone for 14 days. The basal composition of the experimental diet was (in g/kg): casein, 200; palm oil, 100; corn starch, 150; cellulose, 20; mineral mixture (AIN-93G), 35; vitamin mixture (AIN-93), 10; L-cystine, 3.0; choline bitartrate, 2.0 and sucrose to 1 kg.
Project description:Soyfoods have been drawn the interrest in the roles that reducing risk of cardiovascular disease. Among various components, isoflavones have been come to the attention as beneficial soy ingredients. To evaluate the effectiveness of isoflavone content in dietary soybean (Glycine max) on modulating lipid metabolism, hepatic gene expressions involved in lipid metabolism were analyzed in rats. An isoflavone-rich cultivar (Yukipirika) and a conventional cultivar (Fukuyutaka) were employed. A principal component analysis (PCA) of microarray data was used to summarize characteristics of the experimental groups. As a result, the characteristics of the diets were largely explained by the first principal component (PC1). Soybean content in the diets distinctly separated in PC1. In contrast, isoflavone content had little effect on the mRNA expression. The GeneChip data was normalized and summarized by using SuperNORM data service (Skylight Biotech Inc.). Significance of expressional change among groups was tested by 2-way ANOVA on the normalized CEL data, which was deposited in a tab-separated ASCII text format. Principal components were identified on the summarized gene data. Male Splague-Dawley rats were randomly divided into 4 groups and fed an experimental diet for 21 days. The experimental diets were as follows: a diet containing 200 g/kg casein (Cas, n=7); a diet containing two proteins derived equally from casein and Fukuyutaka (conventional cultiver soybean) (F10, n=7); a diet containing two proteins derived from casein and Yukipirika (high-isoflavone soybean) in the proportion of three parts to one (Y05, n=7); a diet containing two proteins derived equally from casein and Yukipirika (Y10, n=8). In each of the groups, five rats with average food intake were used for microarray analysis.