Natural modulators of estrogen biosynthesis and function as chemopreventive agents

Potential of Anti-inflammatory Molecules in the Chemoprevention of Breast Cancer

Breast cancer is a global issue, affecting greater than 1 million women per annum. Over the past two decades, there have been numerous clinical trials involving the use of various pharmacological substances as chemopreventive agents for breast cancer. Various pre-clinical as well as clinical studies have established numerous anti-inflammatory molecules, including nonsteroidal anti-inflammatory drugs (NSAIDs) and dietary phytochemicals as promising agents for chemoprevention of several cancers, including breast cancer. The overexpression of COX-2 has been detected in approximately 40% of human breast cancer cases and pre-invasive ductal carcinoma in-situ lesions, associated with aggressive elements of breast cancer such as large size of the tumour, ER/PR negative and HER-2 overexpression, among others. Anti-inflammatory molecules inhibit COX, thereby inhibiting the formation of prostaglandins and inhibiting nuclear factor-κBmediated signals (NF-kB). Another probable explanation entails inflammation-induced degranulation, with the production of angiogenesis-regulating factors, such as vascular endothelial growth factor, which can be possibly regulated by anti-inflammatory molecules. Apart from NSAIDS, many dietary phytochemicals have the ability to decrease, delay, or stop the progression and/or incidence of breast cancer by their antioxidant action, regulating inflammatory and proliferative cell signalling pathways as well as inducing apoptosis. The rapid progress in chemoprevention research has also established innovative strategies that can be implemented to prevent breast cancer. This article gives a comprehensive overview of the recent advancements in using antiinflammatory molecules in the chemoprevention of breast cancer along with their mechanism of action, supported by latest preclinical and clinical data. The merits of anti-inflammatory chemopreventive agents in the prevention of cardiotoxicity have been described. We have also highlighted the ongoing research and advancements in improving the efficacy of using antiinflammatory molecules as chemopreventive agents.

QSAR and Molecular Docking Studies of Pyrimidine–Coumarin–Triazole Conjugates as Prospective Anti-Breast Cancer Agents

Cancer is a life-threatening disease and is the second leading cause of death worldwide. Although many drugs are available for the treatment of cancer, survival outcomes are very low. Hence, rapid development of newer anticancer agents is a prime focus of the medicinal chemistry community. Since the recent past, computational methods have been extensively employed for accelerating the drug discovery process. In view of this, in the present study we performed 2D-QSAR (Quantitative Structure-Activity Relationship) analysis of a series of compounds reported with potential anticancer activity against breast cancer cell line MCF7 using QSARINS software. The best four models exhibited a r² value of 0.99. From the generated QSAR equations, a series of pyrimidine-coumarin-triazole conjugates were designed and their MCF7 cell inhibitory activities were predicted using the QSAR equations. Furthermore, molecular docking studies were carried out for the designed compounds using AutoDock Vina against dihydrofolate reductase (DHFR), colchicine and vinblastine binding sites of tubulin, the key enzyme targets in breast cancer. The most active compounds identified through these computational studies will be useful for synthesizing and testing them as prospective novel anti-breast cancer agents.

Effects of Resveratrol on Receptor Expression and Serum Levels of Estrogen and Progesterone in the Rat Endometritis Model

Endometritis is characterized by inflammation of the endometrial lining that leads to reduced reproductive potential. Restoring the impaired hormonal balance is an important component of endometritis treatment. The purpose of the current study was to evaluate the effects of resveratrol on estrogen and progesterone hormone status in endometritis. Mature female Sprague Dawley rats were used, and endometritis was induced by intrauterine infusion of Escherichia coli. Animals were treated with resveratrol alone or combined with marbofloxacin. Compared to the non-treated endometritis group, resveratrol treatment reduced serum oestradiol levels, increased serum progesterone levels, enhanced estrogen receptor (ER) expression in the uterine stroma, decreased ESR1 gene expression, and raised ESR2 gene expression. Resveratrol administration combined with marbofloxacin also increased ER expression in the uterine gland and progesterone receptor expression in the uterine epithelium. The findings of this study suggest that the actions of resveratrol on progesterone levels and estrogen receptor expression might be responsible for its beneficial effect in rats with endometritis.

Tumor-targeted Drug Delivery by Nanocomposites

BACKGROUND

Tumor-targeted delivery by nanoparticles is a great achievement towards the use of highly effective drug at very low doses. The conventional development of tumor-targeted delivery by nanoparticles is based on enhanced permeability and retention (EPR) effect and endocytosis based on receptor-mediated are very demanding due to the biological and natural complications of tumors as well as the restrictions on the design of the accurate nanoparticle delivery systems.

METHODS

Different tumor environment stimuli are responsible for triggered multistage drug delivery systems (MSDDS) for tumor therapy and imaging. Physicochemical properties, such as size, hydrophobicity and potential transform by MSDDS because of the physiological blood circulation different, intracellular tumor environment. This system accomplishes tumor penetration, cellular uptake improved, discharge of drugs on accurate time, and endosomal discharge.

RESULTS

Maximum drug delivery by MSDDS mechanism to target therapeutic cells and also tumor tissues and sub cellular organism. Poorly soluble compounds and bioavailability issues have been faced by pharmaceutical industries, which are resolved by nanoparticle formulation.

CONCLUSION

In our review, we illustrate different types of triggered moods and stimuli of the tumor environment, which help in smart multistage drug delivery systems by nanoparticles, basically a multi-stimuli sensitive delivery system, and elaborate their function, effects, and diagnosis.

Engagement of phytoestrogens in breast cancer suppression: Structural classification and mechanistic approach

Cancer is the world's devastating disease, and breast cancer is the most common reason for the death of women worldwide. Many synthetic drugs and medications are provided with their beneficial actions, but all of these have side effects and resistance problems. Natural remedies are coming forward to overcome the disadvantages of synthetic drugs. Among the natural categories, phytoestrogens having a structural similarity of mammalian oestradiol proves its benefit with various mechanisms not only in the treatment of breast cancer but even to prevent the occurrence of postmenopausal symptoms. Phytoestrogens are plant-derived compounds that were utilized in ancient medications and traditional knowledge for its sex hormone properties. Phytoestrogens exert pleiotropic effects on cellular signalling and show effects on estrogen-dependent diseases. However, because of activation/inhibition of steroid hormonal receptor ER-α or ER-β, these compounds induce or inhibit steroid hormonal (estrogen) action and, therefore, have the potential to disrupt hormone (estrogen) signalling pathway. In this review, we have discussed and summarize the effect of certain phytoestrogens and their possible mechanisms that can substantiate advantageous benefits for the treatment of post-menopausal symptoms as well as for breast cancer.

Potential use of ellagic acid for endometriosis treatment: its effect on a human endometrial cell cycle, adhesion and migration

EA treatment decreases cell adhesion and migration of endometrial cells and alters the progression of an endometrial stromal cell line cycle.

Therapeutic effects of resveratrol in Escherichia coli-induced rat endometritis model

Endometritis is an inflammatory disorder of the endometrial lining of the uterine tissue in postpartum stage. Endometritis mostly progresses subclinically and causes infertility through the disruption of the hormonal balance. It has been shown in many studies that resveratrol has anti-inflammatory and antioxidant properties. However, the possible beneficial effects of resveratrol in endometritis have not been determined yet. The aim of the present study is to evaluate the treatment potential of resveratrol in an experimentally induced endometritis model in rats. Endometritis was induced in 12-week-old female, nonpregnant, Sprague Dawley rats. The animals were divided into six groups: control (NaCl 0.9%) and endometritis (NaCl 0.9%), marbofloxacin + PGF_2α, marbofloxacin, marbofloxacin + resveratrol, and resveratrol groups. To induce endometritis, 5 mg/kg/s.c. progesterone was given for 5 days, and then Escherichia coli (50 μl, 1 × 10⁵ cfu/rat) was injected in the right cornu uteri following laparotomy. Sixteen hours after bacterial inoculation, the treatment protocol was applied for 14 days. At the end of the experiment, the total oxidant status (TOS) and total antioxidant status (TAS) were examined spectrophotometrically in uterus tissues. The severity of inflammation in uterus samples and follicular activity in ovarian tissues were histopathologically evaluated. In addition, serum cytokine levels were determined. While TAS in uterine tissue significantly increased in the resveratrol group when compared to that of the other groups (p < 0.05), there was no difference between the groups in TOS (p > 0.05). The inflammation of the endometrium and the numbers of corpus luteum in the endometritis group were highly significant when compared to those of the other groups (p < 0.05). The recovery of inflammation and follicular activity were similar to those of the other groups in resveratrol group. However, it was realized that resveratrol administration reduced serum cytokine levels. According to the results of the current study, resveratrol was found to be effective in the treatment of endometritis with its antioxidant and anti-inflammatory functions.

Estrogenic effects of phytoestrogens derived from Flemingia strobilifera in MCF-7 cells and immature rats

Phytoestrogen (PE) has received considerable attention due to the physiological significance of its estrogenicity. Flemingia strobilifera (FS) has been used as a folk medicine in Asia for the treatment of inflammation, cancer, and infection; however, the estrogenic effects and chemical components of FS have not yet been reported. We aimed to uncover the estrogenic properties and PEs derived from FS using phytochemical and pharmacological evaluation. PEs from FS extract (FSE) were analyzed by NMR, HPLC, and MS. To evaluate estrogenic activity, FSE and its compounds were evaluated by in vitro and in vivo assays, including human estrogen receptor alpha (hERα) binding, estrogen response element (ERE)-luciferase reporter assays, and uterotrophic assays. FSE and its compounds 1-5 showed binding affinities for hERα and activated ERE transcription in MCF-7 cells. Additionally, FSE and compounds 1-5 induced MCF-7 cell proliferation and trefoil factor 1 (pS2) expression. In immature female rats, significant increases in uterine weight and pS2 gene were observed in FSE-treated groups. We identified estrogenic activities of FSE and its bioactive compounds, suggesting their possible roles as PEs via ERs. PEs derived from FSE are promising candidates for ER-targeted therapy for post-menopausal symptoms.

Phytoestrogens in Botanical Dietary Supplements: Implications for Cancer

Phytoestrogens are plant constituents that possess either estrogenic or antiestrogenic activity. Although their activities are weak as compared with human endogenous estrogens, the consumption of phytoestrogens may have clinically significant consequences. A number of botanicals, or the compounds contained therein, have been identified as putative estrogenic agents, but consensus in the biomedical community has been hampered by conflicting data from various in vitro and in vivo models of estrogenic activity. Phytoestrogens may serve as chemopreventive agents while at the same time being capable of promoting growth in estrogen receptor positive cancer cell lines. Furthermore, they may exert their estrogenic influence through receptor-dependent and/or receptor-independent mechanisms. These findings have led to speculation that phytoestrogen intake might be ill advised for patients at an increased risk for hormone-dependent cancers, cancer patients, or cancer survivors. This article will attempt to sort out discrepancies between various experimental models and establish whether certain herbs possess estrogenic activity. The review will focus on 5 popular botanical dietary supplements: Trifolium pratense (red clover), Cimicifuga racemosa (black cohosh), Humulus lupulus (hops), Angelica sinensis (dong quai), and Glycyrrhiza glabra (licorice). It will address their mechanisms of action, clinical evidence bases, and implications for use in cancer.

Anti-aromatase activity of the constituents from damiana (Turnera diffusa)

ETHNOPHARMACOLOGICAL RELEVANCE

Damiana (Turnera diffusa Willd. Ex Schult) has traditionally been used as an herbal aphrodisiac.

AIM OF THE STUDY

The study was aimed to investigate the anti-aromatse activity and the estrogenic activity of the constituents isolated from Turnera diffusa.

MATERIALS AND METHODS

The methanolic extract and 24 compounds isolated from the leaves of Turnera diffusa were evaluated for aromatase activity by using a tritiated-water release assay and for estrogenic activity by using yeast estrogen screen (YES) assay.

RESULTS

The methanolic extract demonstrated a dose-dependent inhibitory activity of the aromatase enzyme with the IC(50) value of 63.1 microg/ml. Among the 24 tested compounds, pinocembrin and acacetin showed the most potent inhibition with IC(50) values of 10.8 and 18.7 microM, respectively. Estrogenic activity was also observed in the extract and three compounds including apigenin 7-glucoside, Z-echinacin and pinocembrin with EC(50) values of 10, 20 and 67 microuM, respectively.

CONCLUSIONS

The extract of Turnera diffusa and two isolated compounds pinocembrin and acacetin could significantly suppress aromatase activity. Moreover, apigenin 7-glucoside, Z-echinacin and pinocembrin showed estrogenic activity.

Breast Differentiation and Its Implication in Cancer Prevention

Sporadic breast cancer is a fatal disease most frequently diagnosed in American women from all ethnic groups, suggesting that primary prevention should be the ultimate goal for breast cancer control. We have developed a novel paradigm for breast cancer prevention arising from the well-established knowledge that an early first full-term pregnancy protects the breast against neoplastic transformation, as well as from our studies of the biological principle underlying this protection. We have shown experimentally that the first pregnancy induces the expression of a specific genomic signature in the breast that results from the completion of a cycle in this organ's differentiation driven by the reproductive process. This signature, in turn, is a biomarker associated with a possible overall lifetime decrease in breast cancer risk. We have shown in an experimental model that a short treatment with human chorionic gonadotropin, a placental hormone secreted during pregnancy, induces the same genomic signature that occurs in pregnancy, inhibiting not only the initiation but also the progression of mammary carcinomas, and stopping the development of early lesions such as intraductal proliferations and carcinoma in situ. These observations indicate that human chorionic gonadotropin given for a very short period, only until this genomic signature is acquired, has significant potential as a chemopreventive agent, protecting the normal cell from becoming malignant. This is a novel concept which challenges the current knowledge that a chemopreventive agent needs to be given for a long period of time to suppress a metabolic pathway or abrogate the function of an organ.