Combination Of Genistein Research Articles

Genistein enhances TRAIL-induced cancer cell death via inactivation of autophagic flux

Tumor necrosis factor-related apoptosis-inducing ligand(TRAIL) is a transmembrane cytokine that is a promising anticancer agent as it selectively induces apoptosis in various types of tumor cells. Autophagic flux, which includes the complete process of autophagy, and suppression of autophagic flux has been increasingly recognized as a favorable and novel therapeutic approach for cancer treatment. Here, we showed that genistein, a major isoflavone compound that exerts its anticancer properties by inhibiting tumor cell proliferation, can induce TRAIL-mediated apoptotic cell death in TRAIL‑resistant human adenocarcinoma A549 cells. Notably, genistein treatment led to a marked increase in the accumulation of microtubule-associated protein1 light chain3(LC3)-II and p62 protein levels. The combination of genistein and TRAIL increased LC3-II, p62, activated caspase-3 and activated caspase-8 accumulation, confirming the inhibition of autophagic flux. Taken together, our results revealed that genistein enhanced TRAIL-induced tumor cell death in TRAIL-resistant A549 adenocarcinoma cells by inhibiting autophagic flux.

Abstract 909: Mechanistic study of synergistic interaction between genistein and equol in MCF-7 human breast cancer cells in vitro

Abstract Soy isoflavones, such as genistein, daidzein, glycitein and equol, a metabolite of daidzein, have been suggested to affect the growth of estrogen-receptor positive breast cancer cells in vitro, and thus considered to be involved in the prevention of breast cancer. We have recently reported that soy isoflavone component mixture has a greater preventive activity against breast cancer rather than genistein alone using chemically induced rat model of hormone-dependent mammary carcinoma. Therefore, we investigated here whether a synergistic interaction exists between genistein and other isoflavone components in estrogen receptor positive MCF-7 cells. Effects of genistein in combination with other isoflavone components on proliferation, apoptosis, cell cycle perturbation, and signal proteins for survival, proliferation, and apoptosis were evaluated by WST-1 assay, FACS analyses, and Western blotting. Synergistic anti-proliferative activity of genistein was observed in combination with three respective isoflavone components, with the most efficacious interaction observed in combination with equal. In FACS study, cells were arrested at the G2/M by genistein but G1/S by equol. However, when these components were combined, cells were arrested at the G2/M, indicating a dominant effect of genistein over equol. Although apoptosis was not evident when cells were treated with either genistein or equol alone, combination treatment markedly induced apoptosis, with demonstrable cleavage of PARP. Upon combination treatment, constitutive activities of Erk1/2 were enhanced, but those of Akt were significantly inhibited, with subsequent reductions of activities of downstream mTOR. Reduced expression of anti-apoptotic Bcl-xL and enhanced expression of proapoptotic Bax were also demonstrated. These data indicate that synergic mechanism of genistein in combination with equol would be mediated by enhanced apoptosis induction through inactivation of Akt and its downstream molecule mTOR, followed by subsequent upregulation of Bax and downregulation of Bcl-xL, thus providing mechanistic rationale for soy isoflavone for the prevention of human breast cancer. Citation Format: MISAKI ONO, KAORU EJIMA, MIKAKO TAKESHIMA, TAKAKO HIGUCHI, REI WAKIMOTO, SHUJI NAKANO. Mechanistic study of synergistic interaction between genistein and equol in MCF-7 human breast cancer cells in vitro. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 909. doi:10.1158/1538-7445.AM2015-909

Abstract 910: Genistein does not alter the effectiveness of taxane chemotherapeutics on human prostate cancer cells

Abstract Prostate cancer (PCa) continues to be a major health problem in the United States. Despite the general effectiveness of androgen deprivation therapy, nearly all cases will progress to become resistant to this first-line treatment. The standard of care for castrate-resistant prostate cancer (CRPC) includes a regimen of chemotherapy with taxane-based agents. Patients with CRPC commonly make dietary modifications and/or use nutritional supplements in addition to their standard of care therapy. Soy products are commonly used by men with PCa, but there are only few publications addressing either the safety or efficacy of soy products in combination with chemotherapy. Previously published studies (Prostate 2013;73:1681-9) suggest that the soy isoflavone genistein has synergistic activity when combined the taxane drug cabazitaxel. We studied the effects of the combination of taxane chemotherapy with genistein. PC-3, 22Rv1, and C4-2 prostate cancer cells were treated with genistein (1, 10, and 100 μM) in combination with docetaxel or cabazitaxel (0.1, 1.0, and 10.0 nM); after 72 hours proliferation was measured using the SRB assay and combination index (CI) analysis was performed to identify synergistic or antagonistic activity. Similar dose response curves were observed for docetaxel and cabazitaxel as expected since both drugs have the same mechanism of action. Compared to cells treated only with taxanes (either docetaxel or cabazitaxel), treatment with physiologically relevant concentrations genistein (1 μM and 10 μM) did not yield additional inhibition or enhancement of proliferation in any of the cell lines studied. There was slight synergistic activity at 100 μM in combination with 1 nM docetaxel in C4-2 (CI = 0.03), PC-3 (CI = 0.60), and 22Rv1 (CI = 0.20) cells. Similarly, slight synergism with 1 nM cabazitaxel was observed in all cell lines: C4-2 (CI = 0.29), PC-3 (CI = 0.40), and 22Rv1 (CI = 0.53). We did not observe any antagonism at clinically relevant concentration combinations of genistein and taxanes. These findings suggest that genistein supplementation is not harmful for PCa patients undergoing chemotherapy, but do not fully support findings of others that demonstrate synergistic activity. Although we did observe an enhancement of growth inhibition, it only occurred at the highest concentration of genistein (100 μM) tested, which is beyond what is achievable through dietary consumption of soy products. Quantities of genistein consumed in the diet or by supplementation are likely not sufficient to enhance the cytotoxicity of chemotherapy, but can be used without reducing the effectiveness of taxane drugs. Citation Format: Jillian N. Eskra, Alaina Dodge, Maarten C. Bosland. Genistein does not alter the effectiveness of taxane chemotherapeutics on human prostate cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 910. doi:10.1158/1538-7445.AM2015-910

Increased Intestinal Absorption of Genistein by Coadministering Verapamil in Rats.

Combination of genistein (GT) and verapamil, a P-glycoprotein (P-gp) inhibitor, can increase GT absorption in situ perfusion technology in rat. To date, little information is yet available about the effect of verapamil on oral absorption of GT in vivo. In this study, a simple and reproducible HPLC-UV method was developed and validated for determination of total GT in rat plasma. Based on this, a pharmacokinetic experiment was designed to characterize biopharmaceutical properties of GT with or without coadministration of verapamil (10.0, 20.0, 30.0mg/kg) in rats. The coadministration of verapamil (30.0mg/kg) with GT caused a significant increase of the maximum GT plasma concentration (1.31-fold vs. GT, P<0.05) and area under the curve (1.39-fold vs. GT, P<0.05). Our data show that verapamil would increase intestinal absorption of GT in rat, suggesting there is some drug-nutrition interaction between verapamil and GT.

A Combination of Intravenous Genistein Plus Mg2+ Enhances Antihypertensive Effects in SHR by Endothelial Protection and BKCa Channel Inhibition.

The effects of combining genistein (GST) plus magnesium (Mg) upon the development of hypertension were examined in 28 twelve-week-old male spontaneous hypertension rats (SHRs). Four experimental groups were tested: SHR (0.9% NaCl and DMSO), SHR + GST (0.9% NaCl and GST 5mg/kg/day), SHR + Mg (Mg(2+) 0.75 mmol/kg/day and DMSO), and SHR + GST + Mg (Mg(2+) 0.75 mmol/kg/day and GST 5mg/kg/day). A group of normotensive genetic control, Wistar-Kyoto (WKY) rats were also included for comparison. Drugs were administrated intravenously daily for 30 days. Systolic blood pressure (SBP) and heart rate were measured by tail-cuff plethysmography every five days. Vascular tone of mesenteric arteries was examined by an isometric force transducer. Big-conductance calcium-activated potassium channel (BKCa) currents were detected by whole-cell patch-clamp techniques. SBP in SHRs was significantly elevated vs. that in WKY rats. GST or Mg lowered SBP of SHRs. Their combination enhanced antihypertensive effects, as indicated by significantly lowered SBP and shorter onset times. GST or Mg individually improved endothelial dysfunction of SHRs. However, again their combination enhanced endothelial protection, nearly restoring maximal relaxation responses to those seen in WKY. BKCa currents in SHRs were increased compared with WKY rats. GST, Mg, and their combination restored BKCa currents to those of WKY rats. The combination of GST and Mg produces antihypertensive effects and improvement of endothelial dysfunction, which are substantially greater than that when either is used individually. These results suggest a novel and feasible protocol for the prevention and treatment of hypertension and related cardio- and cerebro-vascular diseases.

Pharmacological Evaluation of Antidepressant-Like Effect of Genistein and Its Combination with Amitriptyline: An Acute and Chronic Study.

The present study was designed to evaluate the acute and chronic antidepressant effect of genistein in combination with amitriptyline in mice. Animals were divided into six groups (n = 6) for treatment with water, genistein, or amitriptyline, either alone or in combination for ten days. Animals were subjected to locomotor activity testing; tail suspension test (TST); and forced swim test (FST) and immobility time was recorded on day one and day ten. Acute treatment of all treatment groups did not significantly reduce the immobility time (p > 0.05). Chronic treatment of combination of genistein (10 mg/kg) and amitriptyline (5 mg/kg and 10 mg/kg) significantly reduced the immobility time as compared to control group (p < 0.001) and was comparable to amitriptyline alone (10 mg/kg). However, no changes in anti-immobility activity in combination of subeffective doses of genistein (5 mg/kg) and amitriptyline (5 mg/kg) were observed. Genistein at its standard dose (10 mg/kg) rendered synergistic effects in combination with subeffective dose of amitriptyline (5 mg/kg) and additive effects in combination with therapeutic dose of amitriptyline (10 mg/kg).

Sex hormone modulation of both induction and inhibition of CYP1A by genistein in HepG2/C3A cells.

Genistein is a widely consumed phytoestrogen in dietary supplements and has been reported to play roles in both cancer prevention and promotion. These conflicting effects may be complicated by sex differences. Cytochrome P450 1A (CYP1A) participates in carcinogen activation and detoxification, and the enzyme may interact with genistein. Therefore, modulation of CYP1A by a combination of genistein and sex hormones could be responsible for sex differences related to cancer prevention and promotion. In the current study, a human liver cell line, HepG2/C3A, cultured in sex hormone-supplemented media was used to investigate the modulatory effect of genistein on CYP1A gene expression and activity. Genistein exerted both long-term (72 h) induction and short-term (immediate) inhibition of CYP1A activity in HepG2/C3A cells. In the long-term study, CYP1A gene expression and enzyme activity were induced to a greater extent in male hormone-supplemented cells than female ones. In the short-term study, CYP1A activity was inhibited more strongly by genistein in the male hormone-supplemented cells than in the female hormone-supplemented cells. These significant differences suggest that male hormones can modulate the effects of genistein on CYP1A gene expression and activity.

Genistein enhances the effect of cisplatin on the inhibition of non-small cell lung cancer A549 cell growth in vitro and in vivo.

Although cisplatin (DDP) has been reported to be a promising antitumor therapy for non-small cell lung cancer (NSCLC), the effectiveness of the treatment remains limited due to an inherent tumor resistance to DDP. Genistein (GEN) is an abundant, naturally occurring isoflavonoid found in soy products that has been demonstrated to increase the anti-neoplastic activity of certain chemotherapy drugs in multiple tumor types. In the present study, DDP in combination with GEN was selected as a potential treatment to suppress tumor growth and simultaneously reduce the doses of the two drugs required for the treatment of NSCLC. Cell growth inhibition, apoptosis, cell cycle distribution and receptor signaling assays were conducted. In the in vivo study, DDP and GEN, either alone or in combination, were used to treat a xenograft model of the A549 cells. It was found that the combination of low concentrations of DDP and GEN induced significantly greater growth inhibition (P<0.01) and increased apoptosis in the A549 cells compared with either agent alone. In addition, DDP in combination with GEN could significantly suppress tumor growth in vivo compared with either agent alone. Combination treatment significantly suppresses constitutive phosphorylation of AKT and phosphoinositide-3 kinase, which may contribute to the inhibition of tumor growth. Overall, the present data suggested that GEN can increase the anti-neoplastic activity of DDP and that a combination of GEN and DDP is a potential drug candidate for the treatment of NSCLC.

Synergistic cytotoxic effect of genistein and doxorubicin on drug-resistant human breast cancer MCF-7/Adr cells.

The molecular mechanisms underlying genistein-mediated reversal of chemoresistance remains unknown. In the present study, we investigated the molecular mechanisms by which genistein overcomes chemoresistance and its effect on doxorubicin-induced cytotoxicity. Consistent with previous reports, genistein combined with doxorubicin had a synergistic effect on MCF-7/Adr cells, and genistein reduced the chemoresistance of these cells. Genistein treatment increased the intracellular accumulation of doxorubicin but did not influence P-gp function. The combination of genistein and doxorubicin significantly induced cell cycle arrest and apoptosis. Genistein treatment strongly inhibited HER2/neu but not MDR-1 expression at both the mRNA and protein levels. Therefore, our results demonstrated that genistein combined with doxorubicin had a synergistic effect on MCF-7/Adr cells, and the mechanisms likely involve an increase in the intracellular accumulation of doxorubicin and suppression of HER2/neu expression.

Solid-state characterization and solubility of a genistein–caffeine cocrystal

Combination of genistein and caffeine leads to a 1:1 cocrystalline phase, which was identified by means of a solvent-drop grinding experiment and isolated afterwards in a solution-evaporation approach. Obtained cocrystal was characterized by X-ray single-crystal and powder diffraction as well as investigated in terms of thermal stability and Hirshfeld surfaces. A scale-up procedure was provided by slurry technique, enabling solubility determination. Neutral forms of both compounds cocrystallize in a common P21/c space group of the monoclinic crystal system. Analysis of packing and interactions in the crystal lattice reveals formation of molecular layers, formed by O–H⋯O, O–H⋯N and C–H⋯O-type contacts between genistein and caffeine molecules, whereas stabilization of the three-dimensional crystal lattice is provided by π⋯π interactions. Dissolution studies in a 50:50 v/v ethanol–water medium revealed that the maximum solubility of the cocrystalline phase reached 0.861mg/mL after 8h, revealing some degree of enhancement as compared to parent genistein, maximum solubility of which was also reached after 8h and equalled 0.588mg/mL.

Effect of estrogenic binary mixtures in the yeast estrogen screen (YES)

Endocrine disrupting compounds (EDCs) of natural or synthetic origin can interfere with the balance of the hormonal system, either by altering hormone production, secretion, transport, or their binding and consequently lead to an adverse outcome in intact animals. An important aspect is the prediction of effects of combined exposure to two or more EDCs at the same time. The yeast estrogen assay (YES) is a broadly used method to assess estrogenic potential of chemicals. Besides exhibiting good predictivity to identify compounds which interfere with the estrogen receptor, it is easy to handle, rapid and therefore allows screening of a large number of single compounds and varying mixtures. Herein, we applied the YES assay to determine the potential combination effects of binary mixtures of two estrogenic compounds, bisphenol A and genistein, as well as one classical androgen that in vitro also exhibits estrogenic activity, trenbolone. In addition to generating data from combined exposure, we fitted these to a four-parametric logistic dose–response model. As all compounds tested share the same mode of action dose additivity was expected. To assess this, the Loewe model was utilized. Deviations between the Loewe additivity model and the observed responses were always small and global tests based on the whole dose–response data set indicated in general a good fit of the Loewe additivity model. At low concentrations concentration additivity was observed, while at high concentrations, the observed effect was lower than additivity, most likely reflecting receptor saturation. In conclusion, our results suggest that binary combinations of genistein, bisphenol A and trenbolone in the YES assay do not deviate from expected additivity.

Genistein and exercise do not improve cardiovascular risk factors in the ovariectomized rat

Objective To investigate the effect of either genistein, or exercise, or both, on parameters that are indicators of cardiovascular health.Methods We investigated the effect of genistein treatment (300 mg genisten/kg body weight/day), or exercise training, or combined genistein and exercise training, for a period of 6 weeks on physical characteristics, cardiovascular plasma markers, blood pressure, aortic morphology, cardiac structure and oxidative stress in the ovariectomized (OVX) Sprague–Dawley rat. Comparisons were made with intact rats.Results Ovariectomy (compared to intact) resulted in significant decreases in uterine weight (6-fold, p < 0.0001), insulin levels (4-fold, p = 0.0214), insulin/glucose ratio (3-fold, p = 0.0029), and tumor necrosis factor-α plasma levels (2-fold, p < 0.0001). Similarly, aortic blood pressure was significantly increased (by 8%, p < 0.0033) in OVX rats, without changes in aortic luminal or wall dimensions. Heart surface area was significantly increased (by 16%, p = 0.0160) in OVX rats and this was without changes in non-protein thiol levels (a marker of oxidative stress). Physical characteristics were not altered by treatment with genistein, or genistein with exercise, with the exception of increased uterine weight in OVX rats treated under these same conditions. There were no effects of genistein or exercise on indices of blood pressure and aortic morphology in the OVX rat. However, right ventricular nuclei count was reduced in sedentary genistein-treated rats compared to non-treated control OVX rats.Conclusion Our results indicate that administration of genistein at this dose, treadmill running, or the combination of both, are not associated with any improvement in cardiovascular function and structure, and risk factors in an ovariectomy model of postmenopause.

Genistein Reinforces the Inhibitory Effect of Cisplatin on Liver Cancer Recurrence and Metastasis after Curative Hepatectomy

The high recurrence rate after hepatic resection in hepatocellular carcinoma (HCC) is a major obstacle to improving prognosis. The objective of the present study was to explore the function of genistein, a soy-derived isoflavone, in enhancing the inhibitory effect of cisplatin on HCC cell proliferation and on tumor recurrence and metastasis in nude mice after curative hepatectomy. Proliferation of human HCC cells (HCCLM3) was detected by 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (MTT) assay. Synergistic effects of genistein and cisplatin were evaluated with the median-effect formula. Nude mice bearing human HCC xenografts underwent tumour resection (hepatectomy) 10 days post implantation, then received intraperitoneal administration of genistein or cisplatin alone or the combination of the two drugs. 33 days after surgery, recurrent tumours and pulmonary metastasis were evaluated individually. MMP-2 level in recurrent tumours was detected by immunohistochemistry and real-time PCR; MMP-2 expression in HCCLM3 was detected by immunocytochemistry. Genistein and cisplatin both suppressed the growth and proliferation of HCCLM3 cells. The two drugs exhibited synergistic effects even at relatively low concentrations. In vivo, mice in the combined genistein and cisplatin group had a smaller volume of liver recurrent tumors and fewer pulmonary metastatic foci compared with single drug treated groups. Cisplatin upregulated the expression of MMP-2 in both recurrent tumours and HCCLM3, while genistein abolished cisplatin-induced MMP-2 expression. Genistein reinforced the inhibitory effect of cisplatin on HCC cell proliferation and tumour recurrence and metastasis after curative hepatectomy in nude mice, possibly through mitigation of cisplatin-induced MMP-2 upregulation.

Enhanced hematopoietic protection from radiation by the combination of genistein and captopril

The hematopoietic system is sensitive to radiation injury, and mortality can occur due to blood cell deficiency and stem cell loss. Genistein and the angiotensin converting enzyme (ACE) inhibitor captopril are two agents shown to protect the hematopoietic system from radiation injury. In this study we examined the combination of genistein with captopril for reduction of radiation-induced mortality from hematopoietic damage and the mechanisms of radiation protection. C57BL/6J mice were exposed to 8.25Gy 60Co total body irradiation (TBI) to evaluate the effects of genistein and captopril alone and in combination on survival, blood cell recovery, hematopoietic progenitor cell recovery, DNA damage, and erythropoietin production. 8.25Gy TBI resulted in 0% survival after 30days in untreated mice. A single subcutaneous injection of genistein administered 24h before TBI resulted in 72% survival. Administration of captopril in the drinking water, from 1h through 30days postirradiation, increased survival to 55%. Genistein plus captopril increased survival to 95%. Enhanced survival was reflected in a reduction of radiation-induced anemia, improved recovery of nucleated bone marrow cells, splenocytes and circulating red blood cells. The drug combination enhanced early recovery of marrow progenitors: erythroid (CFU-E and BFU-E), and myeloid (CFU-GEMM, CFU-GM and CFU-M). Genistein alone and genistein plus captopril protected hematopoietic progenitor cells from radiation-induced micronuclei, while captopril had no effect. Captopril alone and genistein plus captopril, but not genistein alone, suppressed radiation-induced erythropoietin production. These data suggest that genistein and captopril protect the hematopoietic system from radiation injury via independent mechanisms.

The Synergistic Apoptotic Interaction of Indole-3-Carbinol and Genistein with TRAIL on Endometrial Cancer Cells

Induction of apoptosis in target cells is a key mechanism by which chemotherapy promotes cell killing. The purpose of this study was to determine whether Indole-3-Carbinol (I3C) and Genistein in combination with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induce apoptosis in endometrial cancer cell (Ishikawa) and to assess apoptotic mechanism. The MTT assay and flow cytometry were performed to determine cell viability and cell cycle. The induction of apoptosis was measured by caspase-3 activity test, DNA fragmentation assay, annexin V binding assay and western blot analysis. There was no effect in cell growth inhibition and cell cycle progression alone or in two-combination. However, the treatment of I3C and Genistein followed by TRAIL showed significant cell death and marked increase in sub-G1 arrest. Three-combination treatment revealed elevated expression of DR4, DR5 and cleaved forms of caspase-3, caspase-8, PARP. The Flip was found down regulated. Moreover, increase in caspase-3 activity and DNA fragmentation indicated the induction of apoptosis. The results indicate that I3C and Genistein with TRAIL synergistically induced apoptosis via death receptor dependent pathway. Our findings might provide a new insight into the development of novel combination therapies against endometrial cancer.

Combination with genistein enhances the efficacy of photodynamic therapy against human anaplastic thyroid cancer cells

Photodynamic therapy (PDT) has become one of the emerging options in management of cancer and other diseases. The major goal of PDT is to kill cancer cell without causing any adverse effect to the normal cells. PDT in combination of different therapeutic agents is being evaluated to improve the efficacy of treatment. Genistein, a soy ingredient, has widely been studied against different types of cancer. In the present study, combination of these two therapeutic methods has been studied to evaluate the enhanced effectiveness and find out the mechanism of action. Combination of PDT and genistein has been studied against human thyroid cancer cells SNU 80. Cells were treated with genistein and different concentration of photofrin in PDT singly and conjointly. Viability of SNU 80 cells was analyzed using MTT assay. The cells were stained with Hoechst 33342 and propidium iodide (PI) for morphological observations. Changes in mitochondrial membrane potential and generation of reactive oxygen species (ROS) were also studied by confocal microscopy. Western blot analysis were also performed to find out the expressions of different pro- and anti-apoptotic proteins. From the result, the combination of genistein and photofrin mediated PDT enhanced the apoptotic effect against SNU 80 cells. Proliferation of the cells was inhibited and the mitochondrial membrane depolarisation was observed. ROS level were also increased in combination treatment. The expressions of Caspase 3, Caspase 9, cytochrome c, Caspase 8, Caspae 12 and other apoptosis related proteins were also modified. Thus PDT can induce apoptosis in thyroid cancer cells singly or in combination with genistein. But in combination treatment, the efficacy of inducing apoptosis in SNU 80 cells is much higher than that of individual treatment with genistein or PDT.

Abstract 4029: Enhanced chemosensitivity of estrogen receptor-α (ERα)-negative breast cancer through soybean genistein-induced epigenetic reactivation of ERα

Abstract Estrogen receptor-α (ERα)-negative breast cancer is clinically aggressive and has a poor prognosis due to the lack of estrogen target-directed therapies. The soybean isoflavone, genistein (GE), has been shown to prevent and inhibit breast cancer and recent studies have suggested that GE can enhance the anticancer capacity of an estrogen antagonist, tamoxifen (TAM), especially in ERα-positive breast cancer cells. However, the role of GE in ERα-negative breast cancer remains unknown. In our current studies, we found that GE can reactivate ERα expression and this effect was synergistically enhanced when combined with a histone deacetylase (HDAC) inhibitor, trichostatin A (TSA), in ERα-negative MDA-MB-231 breast cancer cells. GE treatment also re-sensitized ERα-dependent cellular responses to activator 17β-estradiol (E2) and antagonist TAM. Further studies revealed that GE can lead to remodeling of the chromatin structure in the ERα promoter thereby contributing to ERα reactivation. The global enzymatic activities for HDACs and DNA methyltransferases (DNMTs) mediated by GE were altered to favor ERα up-regulation. Consistently, dietary GE significantly reduced the growth of ERα-negative mouse xenograft tumors due at least in part to ERα reactivation. The combination of GE with TAM had more prominent effects on delaying tumor growth than either treatment alone. Collectively, our studies suggest that soybean genistein can epigenetically restore ERα expression, which in turn increases TAM-dependent anti-estrogen chemosensitivity. The results from our studies revealed a novel chemotherapeutic combination approach using bioactive soybean product and anti-hormone therapy in refractory ERα-negative breast cancer which will provide more effective options in breast cancer therapy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4029. doi:1538-7445.AM2012-4029

Molecular targets for botanical compounds genistein and kaempferol to prevent diabetes

Type 2 diabetes (T2D) is a result of chronic insulin resistance and loss of functional â‐cell mass. Thus, a method to simultaneously prevent insulin resistance and protect â‐cells could be a more effective strategy to prevent T2D. Here, we discovered that genistein, an isoflavone present in soybean, directly protects â‐cells from apoptosis ex vivo and promotes islet mass and ameliorates hyperglycemia in streptozotocin‐induced diabetic mice, while kaempferol, a flavonol isolated from gingko biloba, improves insulin sensitivity and glucose homeostasis in high fat diet‐fed mice. Notably, genistein in combination with kaempferol produces a potent additive effect on blood glycemic control in middle‐aged obese diabetic mice. We further found that genistein may protect against â‐cell apoptosis through the G‐protein coupled receptor GPR30‐mediated mechanism, leading to the activation of multiple cell survival pathways, while kaempferol increases energy metabolism, AMPKá activity, and Glut4 protein expression in skeletal muscle cells. These findings demonstrate a potential for using a combination of genistein and kaempferol to prevent diabetes by targeting two critical defects leading to T2D. This work was supported by grants from the ADA (7‐11‐BS‐84 to DL), the NCCAM of NIH (1R21AT004694 to D. Liu), and the Biodesign and Bioprocessing Research Center, College of Agriculture and Life Sciences, Virginia Tech.

A Phase 2 Cancer Chemoprevention Biomarker Trial of Isoflavone G-2535 (Genistein) in Presurgical Bladder Cancer Patients

The soy compound genistein has been observed preclinically to inhibit bladder cancer growth with one potential mechanism being the inhibition of epidermal growth factor receptor phosphorylation (p-EGFR). A phase 2 randomized, placebo-controlled trial investigated whether daily, oral genistein (300 or 600 mg/d as the purified soy extract G-2535) for 14 to 21 days before surgery alters molecular pathways in bladder epithelial tissue in 59 subjects diagnosed with urothelial bladder cancer (median age, 71 years). G-2535 treatment was well tolerated; observed toxicities were primarily mild to moderate gastrointestinal or metabolic and usually not attributed to study drug. Genistein was detected in plasma and urine of subjects receiving G-2535 at concentrations greater than placebo subjects' but were not dose-dependent. Reduction in bladder cancer tissue p-EGFR staining between the placebo arm and the combined genistein arms was significant at the protocol-specified significance level of 0.10 (P = 0.07). This difference was most prominent when comparing the 300-mg group with placebo (P = 0.015), but there was no significant reduction in p-EGFR staining between the 600-mg group and placebo. No difference in normal bladder epithelium p-EGFR staining was observed between treatment groups. No significant differences in tumor tissue staining between treatment groups were observed for COX-2, Ki-67, activated caspase-3, Akt, p-Akt, mitogen-activated protein kinase (MAPK), or p-MAPK. No significant differences in urinary survivin or BLCA-4 levels between treatment groups were observed. Genistein displayed a possible bimodal effect (more effective at the lower dose) on bladder cancer tissue EGFR phosphorylation that should be evaluated further, possibly in combination with other agents.

Effect of a combination of genistein, polyunsaturated fatty acids and vitamins D3 and K1 on bone mineral density in postmenopausal women: a randomized, placebo-controlled, double-blind pilot study

PurposeMany postmenopausal women desire non-pharmaceutical alternatives to hormone therapy for protection against osteoporosis. Soybean isoflavones, especially genistein, are being studied for this purpose. This study examined the effects of synthetic genistein in combination with other potential bone-protective dietary molecules on bone mineral density (BMD) in early postmenopausal women.MethodsIn this 6-month double-blind pilot study, 70 subjects were randomized to receive daily either calcium only or the geniVida™ bone blend (GBB), which consisted of genistein (30 mg/days), vitamin D3 (800 IU/days), vitamin K1 (150 μg/days) and polyunsaturated fatty acids (1 g polyunsaturated fatty acids as ethyl ester: eicosapentaenoic acid/docosahexaenoic acid ratio = ~2/1). Markers of bone resorption and formation and BMD at the femoral neck, lumbar spine, Ward’s triangle, trochanter and intertrochanter, total hip and whole body were assessed.ResultsSubjects supplemented with the GBB (n = 30) maintained femoral neck BMD, whereas in the placebo group (n = 28), BMD significantly decreased (p = 0.007). There was also a significant difference (p < 0.05) in BMD between the groups at Ward’s triangle in favor of the GBB group. Bone-specific alkaline phosphatase and N-telopeptide significantly increased in the GBB group in comparison with those in baseline and in the placebo group. The GBB was well tolerated, and there were no significant differences in adverse events between groups.ConclusionsThe GBB may help to prevent osteoporosis and reduce fracture risk, at least at the hip, in postmenopausal women. Larger and longer-term clinical trials are warranted.