Phytoestrogens induce differential effects on both normal and malignant human breast cellsin vitro

Regulation of the cell cycle and P13K/AKT/mTOR signaling pathway by phthalates in normal human breast cells

OBJECTIVE

To investigate the impact of phthalates, including Butyl benzyl phthalate (BBP), di(n-butyl) phthalate (DBP), and di(2-ethylhexyl) phthalate (DEHP), in breast carcinogenesis.

MATERIALS AND METHODS

MCF-10A normal breast cells were treated with phthalates (100 nM) and 17β-estradiol (E2, 10 nM), which were co-cultured with fibroblasts from normal mammary tissue adjacent to estrogen receptor positive primary breast cancers. Cell viability was determined using a 3-(4,5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Cell cycles were analyzed using flow cytometry. The proteins involving cell cycles and P13K/AKT/mTOR signaling pathway were then evaluated by Western blot analysis.

RESULTS

MCF-10A co-cultured cells treated with E2, BBP, DBP, and DEHP exhibited a significant increase in cell viability using MTT assay. The expressions of P13K, p-AKT, and p-mTOR, as well as PDK1 expression, were significantly higher in MCF-10A cells treated with E2 and phthalates. E2, BBP, DBP, and DEHP significantly increased cell percentages in the S and G2/M phases. The significantly higher expression of cyclin D/CDK4, cyclin E/CDK2, cyclin A/CDK2, cyclin A/CDK1, and cyclin B/CDK1 in MCF-10A co-cultured cells were induced by E2 and these three phthalates.

CONCLUSION

These results provide consistent data regarding the potential role of phthalates exposure in the stimulating proliferation of normal breast cells, enhancing cell viability, and driving P13K/AKT/mTOR signaling pathway and cell cycle progression. These findings strongly support the hypothesis that phthalates may play a crucial role in breast tumorigenesis.

The Importance of Natural Antioxidants in Female Reproduction

Oxidative stress (OS) has an important role in female reproduction, whether it is ovulation, endometrium decidualization, menstruation, oocyte fertilization, or development andimplantation of an embryo in the uterus. The menstrual cycle is regulated by the physiological concentration of reactive forms of oxygen and nitrogen as redox signal molecules, which trigger and regulate the length of individual phases of the menstrual cycle. It has been suggested that the decline in female fertility is modulated by pathological OS. The pathological excess of OS compared to antioxidants triggers many disorders of female reproduction which could lead to gynecological diseases and to infertility. Therefore, antioxidants are crucial for proper female reproductive function. They play a part in the metabolism of oocytes; in endometrium maturation via the activation of antioxidant signaling pathways Nrf2 and NF-κB; and in the hormonal regulation of vascular action. Antioxidants can directly scavenge radicals and act as a cofactor of highly valuable enzymes of cell differentiation and development, or enhance the activity of antioxidant enzymes. Compensation for low levels of antioxidants through their supplementation can improve fertility. This review considers the role of selected vitamins, flavonoids, peptides, and trace elements with antioxidant effects in female reproduction mechanisms.

Improved Activity of Herbal Medicines through Nanotechnology

Phytochemicals or secondary metabolites are substances produced by plants that have been shown to have many biological activities, providing a scientific basis for using herbs in traditional medicine. In addition, the use of herbs is considered to be safe and more economical compared to synthetic medicine. However, herbal medicines have disadvantages, such as having low solubility, stability, and bioavailability. Some of them can undergo physical and chemical degradation, which reduces their pharmacological activity. In recent decades, nanotechnology-based herbal drug formulations have attracted attention due to their enhanced activity and potential for overcoming the problems associated with herbal medicine. Approaches using nanotechnology-based delivery systems that are biocompatible, biodegradable, and based on lipids, polymers, or nanoemulsions can increase the solubility, stability, bioavailability, and pharmacological activity of herbals. This review article aims to provide an overview of the latest advances in the development of nanotechnology-based herbal drug formulations for increased activity, as well as a summary of the challenges these delivery systems for herbal medicines face.

Obesity, the other pandemic: linking diet and carcinogenesis by epigenetic mechanisms

Both obesity and cancer are complex medical conditions that are considered public health problems. The influence of obesity on the predisposition to develop various types of cancer has been observed in a wide variety of studies. Due to their importance as public health problems, and the close relationship between both conditions, it is important to be able to understand and associate them mechanistically. In this review article, we intend to go a little further, by finding relationships between lifestyle, which can lead a person to develop obesity, and how it influences at the cellular and molecular level, affecting gene expression to favor signaling pathways or transcriptional programs involved in cancer. We describe how products of metabolism and intermediate metabolism can affect chromatin structure, participating in the regulation (or dysregulation) of gene expression, and we show an analysis of genes that are responsive to diets high in sugar and fat, and how their epigenetic landscape is altered.

Schisandrol A Exhibits Estrogenic Activity via Estrogen Receptor α-Dependent Signaling Pathway in Estrogen Receptor-Positive Breast Cancer Cells

The aim of this study was to examine the estrogen-like effects of gentiopicroside, macelignan, γ-mangostin, and three lignans (schisandrol A, schisandrol B, and schisandrin C), and their possible mechanism of action. Their effects on the proliferation of the estrogen receptor (ER)-positive breast cancer cell line (MCF-7) were evaluated using Ez-Cytox reagents. The expression of extracellular signal-regulated kinase (ERK), phosphatidylinositol 3-kinase (PI3K), AKT, and estrogen receptor α (ERα) was measured by performing Western blot analysis. 17β-estradiol (E2), also known as estradiol, is an estrogen steroid and was used as a positive control. ICI 182,780 (ICI), an ER antagonist, was used to block the ER function. Our results showed that, except for gentiopicroside, all the compounds promoted proliferation of MCF-7 cells, with schisandrol A being the most effective; this effect was better than that of E2 and was mitigated by ICI. Consistently, the expression of ERK, PI3K, AKT, and ERα increased following treatment with schisandrol A; this effect was slightly better than that of E2 and was mitigated by ICI. Taken together, the ERα induction via the PI3K/AKT and ERK signaling pathways may be a potential mechanism underlying the estrogen-like effects of schisandrol A. This study provides an experimental basis for the application of schisandrol A as a phytoestrogen for the prevention of menopausal symptoms.

Korean red ginseng induces extrinsic and intrinsic apoptotic pathways in MCF-7 breast cancer cells and MCF-10A non-malignant breast cells

BACKGROUND

Among non-hormonal treatments, herbal products are frequently used by women. Korean red ginseng (KRG) is one of the popular herbal medicines. KRG could be one option for relieving menopausal symptoms. However, there are still concerns about the safety for long-term use. In order to be used for alleviating menopausal symptoms, the safety of KRG on breast must be ensured. The purpose of this study was to investigate the effects of KRG on breast cells.

METHODS

MCF-7 and MCF-10A cells were treated with different concentrations of KRG extracts for 48 h. Cell viability was evaluated by MTT assay, and apoptosis by flow cytometry. The expression of apoptosis-related proteins was determined by western blot analysis and estrogen receptor (ER) affinity by ER binding assay.

RESULTS

KRG extract inhibited growth and induced apoptosis of both MCF-7 and MCF-10A cells in dose-dependent manner. KRG extract increased the expression of pro-apoptotic proteins BAX, BAK, and BAD and decreased the expression of anti-apoptotic proteins Bcl-2 and Bcl-XL in both cells. The expressions of Fas and FasL were increased in lower doses, but decreased in higher doses in both cells. Activities of caspase-3, -8 and -9 increased in MCF-10A, while caspase-8 and -9 showed increase in MCF-7. Competition of KRG to E₂ was significant in MCF-7 as KRG dose increased, whereas ER binding was hardly shown in MCF-10.

CONCLUSION

KRG induced apoptosis via extrinsic and intrinsic pathway in MCF-7 breast cancer cells and MCF-10A non-malignant cells. KRG may be safely used with regard to breast cancer risk in postmenopausal women to reduce the vasomotor symptoms.

Synthesis and biological evaluation of resveratrol derivatives with anti-breast cancer activity

Resveratrol is a natural phytoestrogen produced by plants to protect themselves from injury, UV irradiation, and fungal attack. The main active structure is E-resveratrol, which has many pharmacological activities. As the structure of resveratrol is similar to the natural estrogen 17β-estradiol and the synthetic estrogen E-diethylstilbestrol, resveratrol is used in reducing the incidence of breast cancer. However, the therapeutic application of resveratrol is limited due to its low bioavailability. To improve its bioavailability and pharmacological activity, some resveratrol derivatives have been designed and synthesized by substitutions of methoxy, hydroxyl, and other functional groups or heterocyclic esterification either on the "A" or "B" ring, and double bonds were replaced by imine bonds and isometric heterocycles such as naphthyl and imidazole, or synthetic resveratrol oligomers. The structures, synthetic routes, and evaluation of the biological activities of these compounds are discussed. These are aimed at providing some references for the study of resveratrol derivatives in anti-breast cancer treatment.

Nutrition and Breast Cancer: A Literature Review on Prevention, Treatment and Recurrence

Breast cancer (BC) is the second most common cancer worldwide and the most commonly occurring malignancy in women. There is growing evidence that lifestyle factors, including diet, body weight and physical activity, may be associated with higher BC risk. However, the effect of dietary factors on BC recurrence and mortality is not clearly understood. Here, we provide an overview of the current evidence obtained from the PubMed databases in the last decade, assessing dietary patterns, as well as the consumption of specific food-stuffs/food-nutrients, in relation to BC incidence, recurrence and survival. Data from the published literature suggest that a healthy dietary pattern characterized by high intake of unrefined cereals, vegetables, fruit, nuts and olive oil, and a moderate/low consumption of saturated fatty acids and red meat, might improve overall survival after diagnosis of BC. BC patients undergoing chemotherapy and/or radiotherapy experience a variety of symptoms that worsen patient quality of life. Studies investigating nutritional interventions during BC treatment have shown that nutritional counselling and supplementation with some dietary constituents, such as EPA and/or DHA, might be useful in limiting drug-induced side effects, as well as in enhancing therapeutic efficacy. Therefore, nutritional intervention in BC patients may be considered an integral part of the multimodal therapeutic approach. However, further research utilizing dietary interventions in large clinical trials is required to definitively establish effective interventions in these patients, to improve long-term survival and quality of life.

Resveratrol and other dietary polyphenols are inhibitors of estrogen metabolism in human breast cancer cells

Polyphenols in foods and dietary supplements are commonly used for the prevention and treatment of a variety of malignancies, including breast cancer. However, daily intake by patients with breast cancer is controversial, as these compounds may stimulate cancer growth. Estrogens serve key roles in breast cancer cell proliferation; therefore, understanding the interaction between endogenous steroid hormones and natural dietary polyphenols is essential. Currently, comprehensive knowledge regarding these effects remains limited. The current review summarizes the dose-dependent in vitro and in vivo interactions of resveratrol and other dietary polyphenols with estrogen precursors, active estrogens, catechol estrogens and their respective glucuronidated, sulfated, glutathionated or O-methylated metabolites in estrogen receptor alpha negative (ERα-) and positive (ERα+) breast cancer. Which estrogen-metabolizing enzymes are affected by polyphenols is also reviewed in detail. Furthermore, the impacts of dose and therapy duration on disease development and progression in patients with breast cancer are discussed. The present article is part of a Special Issue titled 'CSR 2018'.

Effects of phytoestrogens on the activity and growth of primary breast cancer cells ex vivo

AIM

To explore the ex vivo effects of phytoestrogens on primary human breast cancer cells.

METHODS

Breast cancer cells were obtained from patients who underwent primary breast cancer surgery, which were treated with 10^-8  M 17β-estradiol (E₂ ), one of three phytoestrogens (genistein, resveratrol and quercetin, 10^-7  M), and a combination of E₂ and one of the three phytoestrogens for 48 h. These cells were then extracted for viability and apoptosis assay. The proteins involved in the proliferative and apoptotic pathways were evaluated by western blot analysis.

RESULTS

Human breast cancer cell viability was inhibited by all phytoestrogens but induced by E₂ with or without phytoestrogen. Apoptotic cells, as well as the proteins involved in apoptotic pathway and estrogen receptor (ER) β, were significantly increased in the cells treated with phytoestrogen alone. The use of E₂ with or without a phytoestrogen revealed completely opposite results. The proteins involved in the proliferative pathway and ER α expression were all increased in the cultures with E₂ with or without phytoestrogens.

CONCLUSION

In the presence of E₂ , these phytoestrogens lose the effects of suppressing breast cancer cells; contrastingly, induce growth stimulatory effects by inhibiting apoptosis and stimulating proliferation in primary breast cancer cells. Thus, the effects of phytoestrogens on breast cancer should be considered as E₂ still present in breast cancer tissue.

Effects of phthalates on normal human breast cells co-cultured with different fibroblasts

Whether or not phthalates play a role in breast carcinogenesis remains to be determined. The goal of this study was to explore the effects of phthalates on the growth of normal MCF-10A breast cells modulated by breast fibroblasts. Fibroblasts were derived from normal mammary tissue adjacent to both estrogen receptor (ER) positive and negative primary breast cancers, which were grown separately from nontumorigenic MCF-10A epithelial cells. MCF-10A co-culture cells were treated with 10 nM 17β-estradiol (E₂), Butyl benzyl phthalate (BBP), di(n-butyl) phthalate (DBP), and di(20ethylhexyl) phthalate (DEHP) (10 and 100 nM). After incubation for 120 hours, the cells were harvested and extracted for MTT assay. Western blot analysis was used to evaluate the proliferative pathway proteins and the effects on ER α. Only fibroblasts from ER (+) breast cancer significantly stimulated proliferation of MCF-10A cells. Exposure of the co-culture to E₂, BBP, DBP, DEHP, and E₂ combined with one of these phthalates resulted in significantly increased cell proliferation, as well as proliferating cell nuclear antigen (PCNA) and ER α expressions. The present study demonstrates that phthalates express a significant influence in fibroblast–epithelial interactions, similarly to the effects of E₂ on breast cells. The effects of phthalates on normal breast cells depend upon ER modulating actions. In breast carcinogenesis, phthalates should be considered as having endocrine disrupting potential, even at low concentrations.

ATP2A3 gene as an important player for resveratrol anticancer activity in breast cancer cells

The Ca²⁺ -ATPases from the Sarco/endoplasmic reticulum (SERCA) are fundamental for maintaining intracellular [Ca²⁺ ] homeostasis by pumping Ca²⁺ into the endoplasmic reticulum (ER) of eukaryotic cells. SERCA enzymes are encoded by three different genes (ATP2A1-3), whose expression occurs in a tissue and development stage-specific manner. It has been reported alterations in the expression of SERCA2 and SERCA3 pumps in different types of cancer: oral, lung, colon, stomach, central nervous system, thyroid, breast, and prostate. Resveratrol (RSV), a phytoalexin produced by a wide variety of plants in response to stress situations can modulate cellular processes involved in all stages of carcinogenesis. In this work, we used breast cancer cell lines (MCF-7 and MDA-MB-231) to evaluate mRNA levels of ATP2A2 and ATP2A3 genes in response to RSV treatment. Our results demonstrate that RSV treatment induced the expression of ATP2A3 gene in both cell lines in a time and concentration-dependent manner, while the expression of ATP2A2 gene remained unaffected. The RSV-induced expression of SERCA3 in these breast cancer cell lines produced decreased cell viability, triggered apoptosis and changes in cytosolic Ca²⁺ levels, as well as changes in the capacity for Ca²⁺ release by the ER. These data suggest an important participation of SERCA3 genes in RSV-mediated anti-tumor effect in breast cancer cell lines. Nevertheless, further research is needed to elucidate the molecular mechanisms underlying this effect.

The regulation of tumor suppressor protein, p53, and estrogen receptor (ERα) by resveratrol in breast cancer cells

Resveratrol (RES) is a natural antioxidant found abundantly in grapes, peanuts, and berries, and is known to possess anti-tumorigenic properties. However, there is a noticeable lack of studies on the mechanistic effects of Resveratrol on tumor suppressors. Previous studies from our laboratory have shown the tumor suppressor protein p53 and estrogen receptor-alpha (ERα) to be possible molecular targets for RES. In this study, the anti-estrogenic effects of RES were analyzed on the expression of ERα and p53. The breast cancer cells grown in stripped serum were treated with 60 μM RES, as the optimum concentration based on data obtained from a concentration study using 1-100 μM RES. Our studies indicate that RES caused a decrease in the levels of protein expression of p53 and ERα as compared to the control. Increasing concentrations of RES caused a four-fold decrease in cell number in comparison to estradiol. RES, in conjunction with ICI 182,780 (ICI), caused a down-regulation of both p53 and ERα as compared to the control. These observed effects on cell proliferation and regulation of both p53 and ERα by RES may lead to further understanding of the relationship between tumor suppressor proteins and steroid receptors in breast cancer cells.

Convergent Effects of Resveratrol and PYK2 on Prostate Cells

Resveratrol, a dietary polyphenol, is under consideration as chemopreventive and chemotherapeutic agent for several diseases, including cancer. However, its mechanisms of action and its effects on non-tumor cells, fundamental to understand its real efficacy as chemopreventive agent, remain largely unknown. Proline-rich tyrosine kinase 2 (PYK2), a non-receptor tyrosine kinase acting as signaling mediator of different stimuli, behaves as tumor-suppressor in prostate. Since, PYK2 and RSV share several fields of interaction, including oxidative stress, we have investigated their functional relationship in human non-transformed prostate EPN cells and in their tumor-prone counterpart EPN-PKM, expressing a PYK2 dead-kinase mutant. We show that RSV has a strong biological activity in both cell lines, decreasing ROS production, inducing morphological changes and reversible growth arrest, and activating autophagy but not apoptosis. Interestingly, the PYK2 mutant increases basal ROS and autophagy levels, and modulates the intensity of RSV effects. In particular, the anti-oxidant effect of RSV is more potent in EPN than in EPN-PKM, whereas its anti-proliferative and pro-autophagic effects are more significant in EPN-PKM. Consistently, PYK2 depletion by RNAi replicates the effects of the PKM mutant. Taken together, our results reveal that PYK2 and RSV act on common cellular pathways and suggest that RSV effects on prostate cells may depend on mutational-state or expression levels of PYK2 that emerges as a possible mediator of RSV mechanisms of action. Moreover, the observation that resveratrol effects are reversible and not associated to apoptosis in tumor-prone EPN-PKM cells suggests caution for its use in humans.

Molecular Mechanisms and Therapeutic Effects of (-)-Epicatechin and Other Polyphenols in Cancer, Inflammation, Diabetes, and Neurodegeneration

With recent insight into the mechanisms involved in diseases, such as cardiovascular disease, cancer, stroke, neurodegenerative diseases, and diabetes, more efficient modes of treatment are now being assessed. Traditional medicine including the use of natural products is widely practiced around the world, assuming that certain natural products contain the healing properties that may in fact have a preventative role in many of the diseases plaguing the human population. This paper reviews the biological effects of a group of natural compounds called polyphenols, including apigenin, epigallocatechin gallate, genistein, and (-)-epicatechin, with a focus on the latter. (-)-Epicatechin has several unique features responsible for a variety of its effects. One of these is its ability to interact with and neutralize reactive oxygen species (ROS) in the cell. (-)-Epicatechin also modulates cell signaling including the MAP kinase pathway, which is involved in cell proliferation. Mutations in this pathway are often associated with malignancies, and the use of (-)-epicatechin holds promise as a preventative agent and as an adjunct for chemotherapy and radiation therapy to improve outcome. This paper discusses the potential of some phenolic compounds to maintain, protect, and possibly reinstate health.