Phytoestrogens--mechanism of action and effect on bone markers and bone mineral density

Endocrine Disruptors in Food, Estrobolome and Breast Cancer

The microbiota is now recognized as one of the major players in human health and diseases, including cancer. Regarding breast cancer (BC), a clear link between microbiota and oncogenesis still needs to be confirmed. Yet, part of the bacterial gene mass inside the gut, constituting the so called "estrobolome", influences sexual hormonal balance and, since the increased exposure to estrogens is associated with an increased risk, may impact on the onset, progression, and treatment of hormonal dependent cancers (which account for more than 70% of all BCs). The hormonal dependent BCs are also affected by environmental and dietary endocrine disruptors and phytoestrogens which interact with microbiota in a bidirectional way: on the one side disruptors can alter the composition and functions of the estrobolome, ad on the other the gut microbiota influences the metabolism of endocrine active food components. This review highlights the current evidence about the complex interplay between endocrine disruptors, phytoestrogens, microbiome, and BC, within the frames of a new "oncobiotic" perspective.

Phytoestrogens, novel dietary supplements for breast cancer

While endocrine therapy is considered as an effective way to treat breast cancer, it still faces many challenges, such as drug resistance and individual discrepancy. Therefore, novel preventive and therapeutic modalities are still in great demand to decrease the incidence and mortality rate of breast cancer. Numerous studies suggested that G protein-coupled estrogen receptor (GPER), a membrane estrogen receptor, is a potential target for breast cancer prevention and treatment. It was also shown that not only endogenous estrogens can activate GPERs, but many phytoestrogens can also function as selective estrogen receptor modulators (SERMs) to interact GPERs. In this review, we discussed the possible mechanisms of GPERs pathways and shed a light of developing novel phytoestrogens based dietary supplements against breast cancers.

M, K M, Dey T, Zargar MI, Singh J. Recent advance of herbal medicines in cancer- a molecular approach

Bioactive compounds are crucial for an extensive range of therapeutic uses, and some exhibit anticancer activity. Scientists advocate that phytochemicals modulate autophagy and apoptosis, involved in the underlying pathobiology of cancer development and regulation. The pharmacological aiming of the autophagy-apoptosis signaling pathway using phytocompounds hence offers an auspicious method that is complementary to conventional cancer chemotherapy. The current review aims to explore the molecular level of the autophagic-apoptotic pathway to know its implication in the pathobiology of cancer and explore the essential cellular process as a druggable anticancer target and therapeutic emergence of naturally derived phytocompound-based anticancer agents. The data in the review were collected from scientific databases such as Google search, Web of Science, PubMed, Scopus, Medline, and Clinical Trials. With a broad outlook, we investigated their cutting-edge scientifically revealed and/or searched pharmacologic effects, a novel mechanism of action, and molecular signaling pathway of phytochemicals in cancer therapy. In this review, the evidence is focused on molecular pharmacology, specifically caspase, Nrf2, NF-kB, autophagic-apoptotic pathway, and several mechanisms to understand their role in cancer biology.

A database of integrated molecular and phytochemical interactions of the foxm1 pathway for lung cancer

The FoxM1 pathway is an oncogenic signaling pathway involved in essential mechanisms including control cell-cycle progression, apoptosis and cell growth which are the common hallmarks of various cancers. Although its biological functions in the tumor development and progression are known, the mechanism by which it participates in those processes is not understood. The present work reveals images of the oncogenic FoxM1 pathway controlling the cell cycle process with alternative treatment options via phytochemical substances in the lung cancer study. The downstream significant protein modules of the FoxM1 pathway were extracted by the Molecular Complex Detection (MCODE) and the maximal clique (Mclique) algorithms. Furthermore, the effects of post-transcriptional modification by microRNA, transcription factor binding and the phytochemical compounds are observed through their interactions with the lung cancer protein modules. We provided two case studies to demonstrate the usefulness of our database. Our results suggested that the combination of various phytochemicals is effective in the treatment of lung cancer. The ultimate goal of the present work is to partly support the discovery of plant-derived compounds in combination treatment of classical chemotherapeutic agents to increase the efficacy of lung cancer method probably with minor side effects. Furthermore, a web-based system displaying results of the present work is set up for investigators posing queries at http://sit.mfu.ac.th/lcgdb/index_FoxM1.php.Communicated by Ramaswamy H. Sarma.

Medial preoptic estrogen receptor-beta blunts the estrogen receptor-alpha mediated increases in wheel-running behavior of female rats

Estrogens are believed to enhance rodent voluntary wheel-running through medial preoptic (mPOA) estrogen receptor α (ERα) signaling, with little role attributed to estrogen receptor β (ERβ). Systemic ERβ activation has been shown to mitigate ERα driven increases in wheel-running. Therefore, the present goal was to determine whether ERβ signaling in the mPOA plays a similar modulatory role over ERα. We utilized outbred wild-type (WT) and rats selectively bred for low voluntary running (LVR) behavior to address whether mPOA ERβ signaling blunts ERα driven wheel-running behavior and immediate-early gene (Fos, Zif268, and Homer1) mRNA induction. Further, we addressed baseline mPOA mRNA expressions and circulating 17β-estradiol levels between female WT and LVR rats. Following ovariectomy, WT rats reduced running behavior ∼40 %, with no effect in LVR rats. Intra-medial preoptic injection of the ERα-agonist propylpyrazoletriol (PPT) increased wheel-running ∼3.5-fold in WT rats, while injections of the ERβ-agonist diarylpropionitrile (DPN) or a combination of the two agonists had no effect. Similarly, ERα-agonism (PPT) increased Fos and Homer1 induction ∼3-fold in WT and LVR isolated mPOA neurons, with no effect of the ERβ-agonist DPN alone or in combination with PPT, suggesting medial-preoptic ERβ activity may blunt ERα signaling. LVR rats exhibited higher mPOA mRNA expressions of Esr1, Esr2 and Cyp19a1, lower normalized uterine wet weights and lower 17β-estradiol plasma levels compared to WT, suggesting their low running may be due to low circulating estrogen levels. Collectively, these findings highlight mPOA ERβ as a potential neuro-molecular modulator of the estrogenic control of wheel-running behavior.

Therapeutic applications of herbal medicines for cancer patients

Medicinal herbs and their derivative phytocompounds are being increasingly recognized as useful complementary treatments for cancer. A large volume of clinical studies have reported the beneficial effects of herbal medicines on the survival, immune modulation, and quality of life (QOL) of cancer patients, when these herbal medicines are used in combination with conventional therapeutics. Here, we briefly review some examples of clinical studies that investigated the use of herbal medicines for various cancers and the development of randomized controlled trials (RCTs) in this emerging research area. In addition, we also report recent studies on the biochemical and cellular mechanisms of herbal medicines in specific tumor microenvironments and the potential application of specific phytochemicals in cell-based cancer vaccine systems. This review should provide useful technological support for evidence-based application of herbal medicines in cancer therapy.

Preventive effects of phytoestrogens against postmenopausal osteoporosis as compared to the available therapeutic choices: An overview

Estrogen deficiency is a major risk factor for osteoporosis in postmenopausal women. Although hormone replacement therapy (HRT) has been rampantly used to recompense for the bone loss, but the procedure is coupled with severe adverse effects. Hence, there is a boost in the production of newer synthetic products to ward off the effects of menopause-related osteoporosis. As of today, there are several prescription products available for the treatment of postmenopause osteoporosis; most of these are estrogenic agents and combination products. Nevertheless, in view of the lack of effect and/or toxicity of these products, majority of the postmenopausal women are now fascinated by highly publicized natural products. This is an offshoot of the generalized consensus that these products are more effective and free from any adverse effects. Recently, certain plant-derived natural products, mostly phytoestrogens (isoflavones, lignans, coumestanes, stilbenes, flavonoids) and many more novel estrogen-like compounds in plants have been immensely used to prevent menopause-related depletion in bone mineral density (BMD). Although, a number of papers are published on menopause-related general symptoms, sexual dysfunction, cardiovascular diseases, Alzheimer's disease, diabetes, colon, and breast cancers, there is paucity of literature on the accompanying osteoporosis and its treatment. In view of the controversies on synthetic hormones and drugs and drift of a major population of patients toward natural drugs, it was found worthwhile to investigate if these drugs are suitable to be used in the treatment of postmenopausal osteoporosis. Preparation of this paper is an attempt to review the (a) epidemiology of postmenopausal osteoporosis, (b) treatment modalities of postmenopausal osteoporosis by hormones and synthetic drugs and the associated drawbacks and adverse effects, and (c) prevention and treatment of postmenopausal osteoporosis by phytoestrogens, their drawbacks and toxicity. It is apparent that both the categories of treatment are useful and both have adverse effects, but the plant products are nonscientific and hence are not advised to be used till more studies are undertaken to ensure that the benefits clearly outweigh the risk, in addition to recognition by Food and Drug Administration.

Development of a nanoparticle-based FRET sensor for ultrasensitive detection of phytoestrogen compounds

Phytoestrogens are plant compounds that mimic the actions of endogenous estrogens. The abundance of these chemicals in nature and their potential effects on health require the development of a convenient method to detect phytoestrogens. We have developed a nanoparticle (NP)-conjugated FRET probe based on the human estrogen receptor α (ER) ligand-binding domain (LBD) to detect phytoestrogens. The NP-conjugated FRET probe showed fluorescence signals for genistein, resveratrol and daidzein compounds with Δ ratios of 1.65, 2.60 and 1.37 respectively, which are approximately six times greater compared to individual FRET probes. A significantly higher signal for resveratrol versus genistein and daidzein indicates that the probe can differentiate between antagonistic phytoalexin substances and agonistic isoflavone compounds. NP-conjugated probes demonstrated a wide dynamic range, ranging from 10(-18) to 10(-1) M with EC(50) values of 9.6 × 10(-10), 9.0 × 10(-10) and 9.2 × 10(-10) M for genistein, daidzein and resveratrol respectively, whereas individual probes detected concentrations of 10(-13) to 10(-4) M for phytoestrogens compounds. The time profile revealed that the NP-conjugated probe is stable over 30 h and there is not a significant deviation in the FRET signal at room temperature. These data demonstrate that conjugation of a FRET probe to nanoparticles is able to serve as an effective FRET sensor for monitoring bioactive compounds with significantly increased sensitivity, dynamic range and stability.

Effect of beer drinking on ultrasound bone mass in women

OBJECTIVE

To study the effect of beer consumption on bone mass in a group of healthy women, by using phalangeal bone ultrasound to evaluate the amplitude-dependent speed of sound.

METHODS

This was a cross-sectional study of 1697 healthy women (mean age 48.4 y, body mass index (BMI) 19.0-32.0 kg/m(2)), recruited in a clinical convenience sample and screened for the existence of disease and/or medication that would affect calcium metabolism. Of this total, 710 were premenopausal, 176 were perimenopausal, and 811 were postmenopausal. The women recruited completed a questionnaire that contained detailed sections on current cigarette, alcohol, caffeine, and nutrient consumption. In terms of current alcohol intake, the subjects were classified as moderate drinkers, light drinkers, and nondrinkers. Drinkers were also analyzed according to the kind of alcohol consumed: wine or beer.

RESULTS

Quantitative bone ultrasound values were greater in the beer drinkers compared with the no beer and/or wine drinkers. Taking the amplitude-dependent speed of sound as a dependent variable, and age, BMI, gonadal status, intake of beer and wine, and number of cigarettes per day as independent variables, we found age (beta = -1.52), BMI (beta = -3.86), gonadal status (beta = -27.47), and beer intake (beta = 1.06) to be significant.

CONCLUSION

The greater bone density found in women beer drinkers might be a result of the phytoestrogen content of this alcoholic drink; this requires further investigation.

Comparison of the bone protective effects of an isoflavone-rich diet with dietary and subcutaneous administrations of genistein in ovariectomized rats

Administration of the isoflavone genistein (GEN) has been described to result in bone protection but also to induce uterotrophic responses. To compare bone protective effects of GEN with an isoflavone-rich diet (IRD) and to further elucidate molecular mechanisms involved in bone-protection, ovariectomized rats (OVX) received either a diet low in isoflavone content (IDD) enriched with GEN (42 mg kg(-1)b.wtd(-1)) (GEN(d)), an IRD (14 mg kg(-1)b.wtd(-1) GEN, 14 mg kg(-1)b.wtd(-1) daidzein) or were treated subcutaneously (s.c.) with GEN (10 mg kg(-1)b.wtd(-1)) (GEN(sc)) for 12 weeks. Intact (SHAM), vehicle treated OVX animals and those substituted with 17beta-estradiol (2microg kg(-1)b.wtd(-1)) (E(2)), served as controls. OVX-induced bone loss could be antagonized in E(2), GEN(sc), GEN(d) and IRD groups. Uterine wet weight (UWW) was only stimulated in E(2) and GEN(sc) animals. Serum biomarkers of bone-formation (osteocalcin, osteopontin) and bone-resorption (telopeptides of collagen type I, pyridinoline cross-links) were elevated in OVX compared to SHAM and E(2) animals. Feeding IRD stimulated bone-formation and inhibited bone-resorption, whereas s.c. or dietary administration of GEN only resulted in a stimulation of bone-formation. The results of the present study indicate that in contrast to s.c. administration, dietary intake of GEN resulted in bone protection without stimulation of UWW. Dietary intake of isoflavones by an IRD also did not result in a stimulation of UWW, yet IRD appeared to be more effective in bone protection than administration of pure GEN.

The bone-protective effect of the phytoestrogen genistein is mediated via ER alpha-dependent mechanisms and strongly enhanced by physical activity

Reduced estrogen levels occurring during menopause in women are accompanied by a variety of disorders, e.g. hot flushes, depressions, osteoporosis, increase in body weight and reduced movement drive. The phytoestrogen genistein (GEN) has been demonstrated to have a significant bone-protective potency. In order to study the ER subtype-specific effects of this phytoestrogen on bone in an animal model, ovariectomized (OVX) female Wistar rats were either treated with 17beta-estradiol (E(2)) (4 microg/kg/day), the ER alpha-specific agonist (ALPHA) 16 alpha-LE(2) (10 microg/kg/day), the ER beta-specific agonist (BETA) 8 beta-VE(2) (100 microg/kg/day) or GEN (10 mg/kg/day) for 3 weeks. Vehicle-treated OVX animals served as controls. All animals had the opportunity of voluntary wheel running. Movement activity, changes of body weight and trabecular bone mineral density (BMD) in the tibia were analyzed. E(2) and ALPHA treatment, but not treatment with BETA, significantly increased the movement activity of OVX rats. Treatment with GEN resulted in a significant decrease of movement activity as compared to OVX animals. Bone mineral density in the trabecular area of the tibia and the expression of bone morphogenetic protein-2 (BMP-2) were significantly reduced in OVX- and BETA-treated rats as compared to rats substituted with E(2), ALPHA and GEN. The bone-protective effect of ALPHA was antagonized by co-treatment with the pure antiestrogen Faslodex (ICI). In order to distinguish hormone-dependent effects from those of exercise, we performed an additional experiment where the animals had no opportunity of wheel running. The results demonstrate that physically inactive rats have a stronger decrease of bone mineral density than physically active animals. Very surprisingly, our data demonstrate that GEN has no bone-protective activity in the absence of physical activity. In contrast, ALPHA and E(2) are bone-protective in the presence and absence of physical activity. In conclusion, our data provide evidence that the effects of E(2) on body weight, movement drive and protection of bone mineral density are mediated via ER alpha, whereas activation of ER beta has only a limited effect. Our data also indicate that the bone-protective effects of GEN may be mediated via ER alpha-dependent mechanisms and that physical activity has a strong impact on the bone-protective potency of this phytoestrogen.

The diagnosis and treatment of osteoporosis in men on androgen deprivation therapy for advanced carcinoma of the prostate

PURPOSE

Androgen deprivation therapy (ADT) for advanced prostate cancer increases the risk of osteoporosis. Thus, the practicing urologist should be aware of the appropriate assessment and management. In this article we review the tests designed to diagnose osteoporosis as well as treatment options. We also review methods to monitor the response to therapy and make recommendations for management.

MATERIALS AND METHODS

We performed a MEDLINE (1966 to 2004) search for the terms male, osteoporosis, bone mineral density, prostate cancer, androgen deprivation therapy, bisphosphonates, estrogen and the combinations thereof. We then constructed a management algorithm based on the best evidence available.

RESULTS

Dual energy x-ray absorptiometry of the hip is the gold standard test for osteoporosis. Biochemical markers of bone turnover are not suitable for diagnosis but they have been shown to be useful for monitoring the response to treatment. Smoking cessation, weight bearing exercise, and vitamin D and calcium have been shown to help improve bone mineral density (BMD). Bisphosphonates have been demonstrated to increase BMD and decrease fracture risk in men with osteoporosis. Estrogens have also recently been shown to decrease bone turnover and increase BMD in men on ADT.

CONCLUSIONS

Hip dual energy x-ray absorptiometry should be performed in all men who are anticipated to be on long-term ADT. In addition, all men on ADT should receive vitamin D and calcium supplementation, and perform regular weight bearing exercise. The value of smoking cessation cannot be overstated. In men who have osteopenia or osteoporosis bisphosphonate therapy should be initiated. Estrogen therapy has shown promise but specific recommendations cannot be made at this time.

Complementary and alternative therapeutic approaches in patients with early breast cancer: a systematic review

Complementary and alternative medicine (CAM) is becoming increasingly popular, particularly among patients with breast cancer. We have done a systematic review of studies published between 1995 and February 2005, identified through a comprehensive search. CAM encompasses a wide range of treatment modalities, including dietary and vitamin supplements, mind-body approaches, acupuncture, and herbal medicines. The objectives of CAM treatments are diverse: reduction of therapy-associated toxicity, improvement of cancer-related symptoms, fostering of the immune system and even direct anticancer effects. Clinical trials have generated few or no data on the efficacy of CAM, whether regarding disease recurrence, survival, overall quality of life or safety. Some CAM methods may even have adverse effects or reduce the efficacy of conventional treatment. The primary justification for CAM is based on empirical evidence, case studies, and hypothetical physiological effects. We conclude that available data on CAM modalities in the treatment of early-stage breast cancer does not support their application.

One year soy protein supplementation has positive effects on bone formation markers but not bone density in postmenopausal women

BACKGROUND

Although soy protein and its isoflavones have been reported to reduce the risk of osteoporosis in peri- and post-menopausal women, most of these studies are of short duration (i.e. six months). The objective of this study was to examine if one year consumption of soy-containing foods (providing 25 g protein and 60 mg isoflavones) exerts beneficial effects on bone in postmenopausal women.

METHODS

Eighty-seven eligible postmenopausal women were randomly assigned to consume soy or control foods daily for one year. Bone mineral density (BMD) and bone mineral content (BMC) of the whole body, lumbar (L1-L4), and total hip were measured using dual energy x-ray absorptiometry at baseline and after one year. Blood and urine markers of bone metabolism were also assessed.

RESULTS AND DISCUSSION

Sixty-two subjects completed the one-year long study. Whole body and lumbar BMD and BMC were significantly decreased in both the soy and control groups. However, there were no significant changes in total hip BMD and BMC irrespective of treatment. Both treatments positively affected markers of bone formation as indicated by increased serum bone-specific alkaline phosphatase (BSAP) activity, insulin-like growth factor-I (IGF-I), and osteocalcin (BSAP: 27.8 and 25.8%, IGF-I: 12.8 and 26.3%, osteocalcin: 95.2 and 103.4% for control and soy groups, respectively). Neither of the protein supplements had any effect on urinary deoxypyridinoline excretion, a marker of bone resorption.

CONCLUSION

Our findings suggest that although one year supplementation of 25 g protein per se positively modulated markers of bone formation, this amount of protein was unable to prevent lumbar and whole body bone loss in postmenopausal women.

Herbal remedies in the United States: potential adverse interactions with anticancer agents

PURPOSE

Interest in the use of herbal products has grown dramatically in the Western world. Recent estimates suggest an overall prevalence for herbal preparation use of 13% to 63% among cancer patients. With the narrow therapeutic range associated with most anticancer drugs, there is an increasing need for understanding possible adverse drug interactions in medical oncology.

METHODS

In this article, a literature overview is provided of known or suspected interactions of the 15 best-selling herbs in the United States with conventional allopathic therapies for cancer.

RESULTS

Herbs with the potential to significantly modulate the activity of drug-metabolizing enzymes (notably cytochrome p450 isozymes) and/or the drug transporter P-glycoprotein include garlic (Allium sativum), ginkgo (Ginkgo biloba), echinacea (Echinacea purpurea), ginseng (Panax ginseng), St John' s wort (Hypericum perforatum), and kava (Piper methysticum). All of these products participate in potential pharmacokinetic interactions with anticancer drugs.

CONCLUSION

It is suggested that health care professionals and consumers should be aware of the potential for adverse interactions with these herbs, question their patients on their use of them, especially among patients whose disease is not responding to treatments as expected, and urge patients to avoid herbs that could confound their cancer care.