Progesterone inhibits growth and induces apoptosis in cancer cells through modulation of reactive oxygen species

Cadmium as a male reproductive toxicant and natural and non-natural ways to tackle it: a review

Cadmium (Cd) is a naturally occurring environmental pollutant, a toxic substance that causes oxidative stress. According to epidemiological studies, the data suggested that environmental and occupational Cd exposure may be related to several diseases and severe testicular damage. However, studies are going on to explore the mechanism of Cd-induced male reproductive toxicity and its treatment strategies. Currently, researchers are focusing on naturally occurring bioactive compounds, plant extracts, and biochemical, which have better efficacy, less toxicity, and high bioavailability. This review focuses on the mechanistic effect of Cd on testicular toxicity and different categories of compounds having a beneficial impact on Cd-induced male reproductive toxicity. Some potent bioactive antioxidants are quercetin, caffeic acid phenethyl ester, cyanidin-3-O-glucoside, curcumin, and silymarin. In comparison, plant extracts are Costus afer leaf methanol extract, methanol root extract of Carpolobia lutea, red carrot methanolic extract, Panax ginseng extract, and biochemicals including melatonin, progesterone, glutamine, L-carnitine, and selenium. Advanced and more detailed studies are needed on these compounds to explore their mechanism in attenuating Cd-induced testicular toxicity and can be potential therapeutics in the future.

Downregulation of pattern recognition receptors on macrophages involved in aggravation of endometriosis

PROBLEM

In women of reproductive age, endometriosis may contribute to dysmenorrhea, chronic pelvic pain, dyspareunia, infertility, adenomyosis, and endometrial ovarian cyst (EOC). Recent studies have shown that chronic inflammation occurs in the pelvis of endometriosis patients and that this inflammation is exacerbated by immunosuppression, leading to survival endometrial debris. However, the detailed immunological mechanisms underlying the aggravation of inflammation and immunosuppression in endometriosis patients remain unclear.

METHOD OF STUDY

We investigate the alarmins (high-mobility group box-1, IL-33, IL-1α, and S100B protein), proinflammatory cytokines (IL-6 and IL-1β), and immune cells (CD8+ T cells, CD4+ T cells, natural killer cells, natural killer T cells, dendritic cells, and macrophages) in peritoneal fluid of patients with EOC using enzyme-linked immunosorbent assay, electrochemiluminescence, and flow cytometry. Then, we analyzed the correlation between these factors and the aggravating indicators of endometriosis, tumor size and revised American Society for Reproductive Medicine (r-ASRM) score.

RESULTS

Unexpectedly, there was no correlation between each alarmin level and aggravating indicators. However, the expression of pattern recognition receptors, toll-like receptor 4, and receptor of advanced glycation end-products on macrophages was inversely correlated with aggravating indicators.

CONCLUSIONS

The aggravation of endometriosis is associated with a decrease in alarmin receptors but not alarmin levels. Investigation of innate immune systems, such as alarmins and their receptors, may help elucidate new mechanisms of endometriosis.

Reevaluating the Role of Progesterone in Ovarian Cancer: Is Progesterone Always Protective?

Ovarian cancer (OC) represents a collection of rare but lethal gynecologic cancers where the difficulty of early detection due to an often-subtle range of abdominal symptoms contributes to high fatality rates. With the exception of BRCA1/2 mutation carriers, OC most often manifests as a post-menopausal disease, a time in which the ovaries regress and circulating reproductive hormones diminish. Progesterone is thought to be a "protective" hormone that counters the proliferative actions of estrogen, as can be observed in the uterus or breast. Like other steroid hormone receptor family members, the transcriptional activity of the nuclear progesterone receptor (nPR) may be ligand dependent or independent and is fully integrated with other ubiquitous cell signaling pathways often altered in cancers. Emerging evidence in OC models challenges the singular protective role of progesterone/nPR. Herein, we integrate the historical perspective of progesterone on OC development and progression with exciting new research findings and critical interpretations to help paint a broader picture of the role of progesterone and nPR signaling in OC. We hope to alleviate some of the controversy around the role of progesterone and give insight into the importance of nPR actions in disease progression. A new perspective on the role of progesterone and nPR signaling integration will raise awareness to the complexity of nPRs and nPR-driven gene regulation in OC, help to reveal novel biomarkers, and lend critical knowledge for the development of better therapeutic strategies.

In vitro chemo-preventive efficacy of synthetic progestin Norethindrone in human epithelial ovarian cancer

Progestin-only based oral contraceptives are majorly used as 'minipill' to prevent unintended pregnancy and treat conditions like polycystic ovary syndrome, hirsutism, and acne. However, the dearth of literature has constrained our comprehension of the exogenous progestin in relation to ovarian cancer progression. Therefore, the aim of the present study was to evaluate the chemo-preventive potential of synthetic progestin Norethindrone (NET) in epithelial ovarian cancer in vitro. Briefly, SKOV3 cells were treated with 1, 10 and 100 µM concentrations of NET for seven days period. The assays for cell viability, wound-healing, cell cycle progression, detection of reactive oxygen species (ROS) and apoptosis were executed to illustrate the protective role of NET. To further clarify the underlying process, quantitative analysis of mRNA levels of oncogenes linked to angiogenesis, inflammation, proliferation, and metastasis (VEGF, HIF-1α, COX-2, and PGRMC1) and tumour suppressor (TP53) genes was conducted. Our study revealed that NET treatment significantly reduced SKOV3 cell growth by inducing cell cycle arrest at G2/M phase, elevating ROS levels, triggering cell death via apoptosis and necrosis, and inhibiting cell migration in a dose-dependent manner. Notably, NET also upregulated TP53 expression while concurrently downregulating VEGF, HIF-1α, COX-2, and PGRMC1 expression. Our results demonstrated that the chemo-preventive effect of Norethindrone may originate from the interaction of genes which exert a protective effect against ovarian carcinogenesis. The current findings also support further investigation, which may lead to changes in prescription practices or health-related advice for women.

Association of functional superoxide gene polymorphism with chlamydia trachomatis-associated recurrent spontaneous abortion

BACKGROUND

Oxidative stress generated by Chlamydia trachomatis infection is associated with reproductive complications such as recurrent spontaneous abortion. Aim of prospective study was to evaluate whether single nucleotide polymorphisms (SNPs) of SOD1 and SOD2 gene are associated with C. trachomatis-infected recurrent spontaneous abortion (RSA).

METHODS

150 patients with history of RSA and 150 patients with history of successful deliveries were recruited from Department of Obstetrics and Gynecology, Safdarjung hospital, New Delhi, India. Urine and non-heparinized blood samples were collected and C. trachomatis was detected by polymerase chain reaction (PCR). Using qualitative real time PCR, SNPs rs4998557 (SOD1) and rs4880 (SOD2) were screened in enrolled patients. Level of 8-hydroxyguanosine (8-OHdG), 8-isoprostane (8-IP), progesterone and estrogen was determined by enzyme-linked immunosorbent assays and correlated with SNPs.

RESULTS

Significant differences were found in frequency of AA genotype of SOD1 gene among RSA patients versus controls, (82% and 54.66%, respectively; p = 0.02; OR 0.40; CI 95%). Frequency of AA genotype of SOD1 gene among RSA patients with C. trachomatis infection was 87.33%, while in uninfected RSA patients was 71.33% (p < 0.0001; OR 8; CI 95%). No significant relation was found between SOD2 (rs4880) genotype and RSA. Furthermore, significant increase in 8-OHdG, 8-IP and estrogen and significant decrease in progesterone was observed among patients carrying AA genotype.

CONCLUSIONS

Findings suggest the clinical importance of AA genotype along with 8-OHdG, 8-IP and estrogen and progesterone in screening C. trachomatis-infected RSA women.

Progesterone exerts a neuroprotective action in a Parkinson's disease human cell model through membrane progesterone receptor α (mPRα/PAQR7)

Parkinson's disease (PD) is the second most common neurodegenerative disease worldwide, and current treatment options are unsatisfactory on the long term. Several studies suggest a potential neuroprotective action by female hormones, especially estrogens. The potential role of progestogens, however, is less defined, and no studies have investigated the potential involvement of membrane progesterone receptors (mPRs). In the present study, the putative neuroprotective role for mPRs was investigated in SH-SY5Y cells, using two established pharmacological treatments for cellular PD models, 6-hydroxydopamine (6-OHDA) and 1-methyl-4-phenylpyridinium (MPP+). Our results show that both the physiologic agonist progesterone and the specific mPR agonist Org OD 02-0 were effective in reducing SH-SY5Y cell death induced by 6-OHDA and MPP⁺, whereas the nuclear PR agonist promegestone (R5020) and the GABA_A receptor agonist muscimol were ineffective. Experiments performed with gene silencing technology and selective pharmacological agonists showed that mPRα is the isoform responsible for the neuroprotective effects we observed. Further experiments showed that the PI3K-AKT and MAP kinase signaling pathways are involved in the mPRα-mediated progestogen neuroprotective action in SH-SY5Y cells. These findings suggest that mPRα could play a neuroprotective role in PD pathology and may be a promising target for the development of therapeutic strategies for PD prevention or management.

Highly Expressed Progesterone Receptor B Isoform Increases Platinum Sensitivity and Survival of Ovarian High-Grade Serous Carcinoma

Simple Summary

Ovarian high-grade serous carcinoma is the deadliest ovarian cancer. Cancer cells develop resistance to anti-cancer regimens leading to poor prognosis. Previous studies showed that the progesterone receptor was associated with better rates of survival of ovarian cancer patients. We aimed to investigate the association between the progesterone receptor and its isoform-B and platinum sensitivity of ovarian high-grade serous carcinoma. We found that strong progesterone receptor-B expression was associated with better platinum sensitivity and better survival in high-grade serous ovarian cancer patients. Our clinical data also showed that a high expression of progesterone receptor-B and optimal debulking were the independent factors associated with better platinum sensitivity. In a cell model, enhancing progesterone receptor-B expression and progesterone treatment increased platinum sensitivity and platinum-related apoptosis of the ovarian cancer cells. These might be potential therapeutic targets of ovarian high-grade serous carcinoma.

Abstract

Background: Expression of the progesterone receptor (PR) has been reported to influence survival outcomes in patients with ovarian high-grade serous carcinoma (HGSC). In the present study, we attempted to investigate the association among PR and its isoforms’ expression, platinum sensitivity, and survival in ovarian HGSC. Material and methods: This retrospective study reviewed ovarian HGSC patients who received surgery followed by adjuvant chemotherapy. We analyzed total PR and PR isoform-B (PR-B) expression by immunohistochemical staining and quantified using the H-score. Then, we compared platinum sensitivity and survival outcomes between those patients with weak and strong PR-B expression. Cisplatin viability assays were carried out in ovarian HGSC cell lines (OC-3-VGH and OVCAR-3) with different PR-B expression. Results: Among 90 patients, 49 and 41 patients were considered to have platinum-sensitive and platinum-resistant disease, respectively. Pearson’s correlation model showed that the H-score of total PR correlated positively with PR-B (r = 0.813). The PR-B H-score of tumors was significantly higher in the platinum-sensitive group (p = 0.004). Multivariate analysis revealed that the PR-B H-score and optimal debulking status were independent factors predicting platinum sensitivity. When compared with strong PR-B expression, patients with weak PR-B had significantly poorer progression-free (p = 0.021) and cancer-specific survival (p = 0.046). In a cell model, cisplatin-resistant OC-3-VGH cells expressed a lower level of PR-B than wild-type cells. Overexpression of PR-B or progesterone could increase cisplatin sensitivity in both OC-3-VGH and OVCAR-3 cells via the mechanism of promoting cisplatin-related apoptosis. Conclusions: When compared to weak PR-B, ovarian HGSC patients with a strong PR-B expression had a better chance of platinum sensitivity and survival, and this finding was compatible with our experimental results. Progesterone seemed to be a platinum sensitizer, but the value of adding progesterone in the treatment of ovarian HGSC should be further investigated.

DMF Activates NRF2 to Inhibit the Pro-Invasion Ability of TAMs in Breast Cancer

Tumor-associated macrophages (TAMs) account for more than 50% of the cells in the tumor immune microenvironment of patients with breast cancer. A high TAM density is associated with a poor clinical prognosis. Targeting TAMs is a promising therapeutic strategy because they promote tumor growth, development, and metastasis. In this study, we found that dimethyl formamide (DMF) significantly inhibited the tumor invasion-promoting ability of TAMs in the co-culture system and further showed that DMF functioned by reducing reactive oxygen species (ROS) production in TAMs. The orthotopic 4T1 cell inoculation model and the spontaneous mouse mammary tumor virus-polyoma middle tumor-antigen tumor model were used to evaluate the antitumor effect of DMF. The results showed that DMF significantly inhibited tumor metastasis and increased T-cell infiltration into the tumor microenvironment. Mechanistically, NRF2 activation was necessary for DMF to exert its function, and DMF can play a role in breast cancer as an anticancer drug targeting TAMs.

A Narrative Review of the Role of Diet and Lifestyle Factors in the Development and Prevention of Endometrial Cancer

Simple Summary

The incidence and prevalence of endometrial cancer is increasing globally. The main factors involved in this increase have been the way women live today and what they eat and drink. In fact, the obesity pandemic that is sweeping across the planet is considered to be the main contributory feature. This review aims to introduce to a new audience, those that are not experts in the field, what is known about the different types of endometrial cancer and the mechanisms for their induction and protection. We also seek to summarise the existing knowledge on dietary and lifestyle factors that prevent endometrial development in susceptible populations and identify the main problem in this arena; the paucity of research studies and clinical trials that investigate the interaction(s) between diet, lifestyle and endometrial cancer risk whilst highlighting those areas of promise that should be further investigated.

Abstract

Endometrial cancer is the most common cancer affecting the reproductive organs of women living in higher-income countries. Apart from hormonal influences and genetic predisposition, obesity and metabolic syndrome are increasingly recognised as major factors in endometrial cancer risk, due to changes in lifestyle and diet, whereby high glycaemic index and lipid deposition are prevalent. This is especially true in countries where micronutrients, such as vitamins and minerals are exchanged for high calorific diets and a sedentary lifestyle. In this review, we will survey the currently known lifestyle factors, dietary requirements and hormonal changes that increase an individual’s risk for endometrial cancer and discuss their relevance for clinical management. We also examine the evidence that everyday factors and clinical interventions have on reducing that risk, such that informed healthy choices can be made. In this narrative review, we thus summarise the dietary and lifestyle factors that promote and prevent the incidence of endometrial cancer.

Ovarian hormones-autophagy-immunity axis in menstruation and endometriosis

Menstruation occurs in few species and involves a cyclic process of proliferation, breakdown and regeneration under the control of ovarian hormones. Knowledge of normal endometrial physiology, as it pertains to the regulation of menstruation, is essential to understand disorders of menstruation. Accumulating evidence indicates that autophagy in the endometrium, under the regulation of ovarian hormones, can result in the infiltration of immune cells, which plays an indispensable role in the endometrium shedding, tissue repair and prevention of infections during menstruation. In addition, abnormal autophagy levels, together with resulting dysregulated immune system function, are associated with the pathogenesis and progression of endometriosis. Considering its potential value of autophagy as a target for the treatment of menstrual-related and endometrium-related disorders, we review the activity and function of autophagy during menstrual cycles. The role of the estrogen/progesterone-autophagy-immunity axis in endometriosis are also discussed.

The apoptotic effects of progesterone on breast cancer (MCF-7) and human osteosarcoma (MG-636) cells

Purpose

Progesterone has been reported to inhibit the proliferation of breast cancer and osteosarcoma cells; however, its inhibitory mechanism has not yet been clarified. The aim of the present study was to clarify the effects of progesterone on apoptosis in breast cancer (MCF-7) and human osteosarcoma (MG-63) cells.

Materials and methods

In this experimental study the cytotoxic effect of progesterone was measured in MCF-7 and MG-63 cells exposed to different concentrations of progesterone using MTT assay, and effective concentrations were identified. The expression levels of the Bax, P53 and Bcl-2 genes were evaluated by real-time PCR, and caspase-3, 8 and 9 activity levels were determined using a colorimetric method. Hoechst staining and flow cytometry were used to confirm apoptosis. The data were statistically analyzed using one-way analysis of variance (ANOVA) and independent-samples t-test.

Results

Compared to the control group, we observed a significant increase in the expression levels of the Bax and P53 genes and the activity levels of caspase-3 and 9, and a significant decrease in the expression level of the Bcl-2 gene in MCF-7 and MG-63 treated with effective concentration of progesterone. The caspase-8 activity level did not change significantly in treated MG-63 but increased in treated MCF-7 cells. Hoechst staining and flow cytometry results confirmed apoptosis in the cells exposed to effective concentration of progesterone.

Conclusions

The cytotoxic effect of progesterone on breast cancer and osteosarcoma cells was mediated by apoptotic pathways. In this context, progesterone triggers the extrinsic and intrinsic apoptotic pathways in MCF-7 cells and induces the intrinsic apoptotic pathway in MG-63 cells.

Effects of the menstrual cycle on oxidative stress and antioxidant response to high-intensity intermittent exercise until exhaustion in healthy women

BACKGROUND

This study aimed to investigate the effects of the menstrual cycle on the oxidative stress and antioxidant response during high-intensity intermittent exercise until exhaustion in healthy women who habitually exercised.

METHODS

Ten women with normal menstrual cycle completed 2 menstrual cycle phases, including the early follicular phase (FP) and the midluteal phase (LP). High-intensity exercise until exhaustion was performed on each test day. Blood samples were collected before the exercise (Pre), immediately after the exercise (Post0), and 60 minutes after the exercise (Post60). The levels of estradiol; progesterone; oxidative stress, which was measured as diacron reactive oxygen metabolites (d-ROMs); and antioxidant capacity, which was measured as the biological antioxidant potential (BAP), were assessed.

RESULTS

The levels of serum estradiol and progesterone at Pre were significantly higher in the LP than in the FP (P<0.01). There were no significant differences in the d-ROMs, BAP, and BAP/d-ROMs between the FP and the LP at Pre, Post0, and Post60. Compared with the FP, the LP had significantly lower d-ROMs change rate from Pre at Post0 and Post60 (P<0.05). Moreover, the BAP/d-ROMs change rate from Pre showed a significantly higher trend in the LP than in the FP at Post0 and Post60 (P=0.06).

CONCLUSIONS

In women with regular menstrual cycle, oxidative stress during exercise and recovery may be eliminated during the LP, when the estradiol and progesterone levels are higher, compared with those during the FP.

Effect of progesterone and first evidence about allopregnanolone action on the progression of epithelial human ovarian cancer cell lines

Ovarian carcinoma is one of the most common cause of death by gynecologic cancer. Several epidemiological and in vitro studies have shown controversial data about progesterone effects in ovarian cancer. Progesterone can be converted in its active metabolite, allopregnanolone, its effects in ovarian cancer are still unknown. Previously, we demonstrated that allopregnanolone modifies ovarian morphophysiology, being able to alter critical process of tumor development such as proliferation, apoptosis and angiogenesis. Taking into account these antecedents, we investigated the effect of progesterone and allopregnanolone on proliferation, apoptosis, clonogenic capacity and migration on two epithelial human ovarian cancer cell lines, IGROV-1 and SKOV-3. To this end, IGROV-1 and SKOV-3 cells were exposed to a range of progesterone and allopregnanolone concentrations (10^-11 to 10^-5 M) for 72 h. Proliferation was analyzed by MTT and Ki67 expression. Apoptosis was measured by immunocytochemistry of cleaved caspase 3. Clonogenic capacity was evaluated by counting colonies. Migration was analyzed by wound assay. We found that allopregnanolone increased proliferation and Ki67 expression respect to control on IGROV-1 cells, while expression of cleaved caspase 3 did not change in any cell line studied. IGROV-1 clonogenic capacity was also increased by allopregnanolone treatment. Both steroids, progesterone and allopregnanolone, increased IGROV-1 migration in a concentration dependent manner. None of the steroids tested modified SKOV-3 biological behavior analized. This is the first evidence that allopregnanolone, a progesterone metabolite, affects critical events in tumor development of human epithelial ovarian cancer. These results could have an impact in the future in clinic diagnosis, prognosis and treatment of ovarian cancer patients. The regulation of progesterone and allopregnanolone steroideogenesis and their molecular mechanisms might be considered as potential therapeutic tool in ovarian cancer.

Biotransformation of progestonic hormone dydrogesterone with Macrophomina phaseolina, and study of the effect of biotransformed products on phagocytes oxidative burst

Biotransformation of a synthetic progestonic hormone dydrogesterone (1), C₂₁H₂₈O₂, with a plant pathogenic fungus Macrophomina phaseolina yielded two new 2 and 3, and a known 4 metabolites. These analogues were identified as, 3β,11α-dihydroxy-5β,9β,10α-pregna-7-ene-6,20-dione (2), 15β-hydroxy-9β,10α-pregna-4,6-diene-3,20-dione (3), and 8α-hydroxy-9β,10α-pregna-4,6-diene-3,20-dione (4). Major structural changes were observed in metabolite 2. New metabolite 3 showed anti-inflammatory potential, and was found to be the potent inhibitor of intracellular reactive oxygen species (ROS) from whole blood phagocytes (IC₅₀ = 4.2 ± 0.3 μg/mL), as compared to standard drug Ibuprofen (IC₅₀ = 11.2 ± 1.9 μg/mL). The metabolites 2, 3, and 4 were found to be non-toxic to NIH-3T3 (CRL-1658) normal cell line. This indicated anti-inflammatory potential of resulting metabolites.

Cadmium induced damage in Wistar rats, ameliorative potentials of progesterone

Asides the increased human exposure to Cadmium containing products; the adverse effects of Cadmium on human health is further exacerbated by its toxicity at low dosage, long biologic half-life and low rate of excretion from the body. This study investigated the protective potential of progesterone on cadmium-induced damage in Wistar rats. Adult male Wistar rats received CdCl₂ once daily for 21 days. Progesterone was given 30 min. after administration of CdCl₂ while 3 other groups were given distilled water, CdCl₂ and progesterone alone. Blood samples were collected from the animals for the determination of liver function and antioxidant status while the liver, kidney, cerebellar and hippocampal tissues were excised and fixed in Neutral buffered formalin for histopathological studies. While Cadmium caused changes in liver function parameters which were indicative of oxidative stress, pre-treatment with progesterone caused restoration to values which were non-significant to the control. Similar findings were made for G6PD, GSH, SOD, CAT and MDA. Histopathology revealed tissue damage in the Cd treated group; this was attenuated by prior treatment with progesterone. Progesterone ameliorated the free radical induced oxidative stress and tissue injury arising from exposure to Cadmium; attention should be given to its antioxidant role in Cadmium toxicity.

Polycystic ovarian syndrome is linked to increased oxidative stress in Omani women

Purpose

Literature emerging from Western countries has reported increased levels of serum oxidative stress markers among polycystic ovarian syndrome (PCOS) women. In the Arab region, there is limited research about the association between oxidative stress and PCOS. This study aimed to compare sociodemographic and clinical characteristics, sex hormones, and oxidative stress indices between PCOS women and non-PCOS women and to investigate the correlation between oxidative stress biomarkers and sex hormones.

Methods

This hospital-based case-control study was conducted among reproductive-aged women. The study included 51 women diagnosed with PCOS (as per Rotterdam 2003 criteria) and 45 control women who were not diagnosed with PCOS. Serum samples were collected to measure the mean levels of the following sex hormones: total testosterone, dehydroepiandrosterone sulfate, estradiol and progesterone, as well as to measure biomarkers of oxidative stress including glutathione peroxidase (GPx), glutathione reductase (GR), glutathione (GSH), and total antioxidant capacity (TAC).

Results

PCOS women exhibited clinical characteristics including irregular menses, hirsutism, and acne compared to the control group (P≤0.05). Significant differences were observed in the waist-hip ratio of PCOS women compared to controls (P=0.004). GPx and GR activity levels appeared to be higher among PCOS women compared to controls; however, no statistically significant differences were observed between the two groups (P>0.05). PCOS women had lower GSH and TAC levels compared to controls with a statistically significant difference observed for GSH levels (P=0.006). Correlation analysis showed a significant negative correlation between estradiol and TAC in the total sample (r=-0.284, P=0.005).

Conclusion

This study provides supportive evidence that oxidative stress might play a role in the pathogenesis of PCOS and, hence, oxidative stress parameters could be suggested as diagnostic markers for early diagnosis of high-risk groups. Also, the study provides supportive evidence that obesity and sex hormones, particularly estradiol, in PCOS may contribute to enhanced oxidative stress.

Progesterone influences cytoplasmic maturation in porcine oocytes developing in vitro

Progesterone (P4), an ovarian steroid hormone, is an important regulator of female reproduction. In this study, we explored the influence of progesterone on porcine oocyte nuclear maturation and cytoplasmic maturation and development in vitro. We found that the presence of P4 during oocyte maturation did not inhibit polar body extrusions but significantly increased glutathione and decreased reactive oxygen species (ROS) levels relative to that in control groups. The incidence of parthenogenetically activated oocytes that could develop to the blastocyst stage was higher (p < 0.05) when oocytes were exposed to P4 as compared to that in the controls. Cell numbers were increased in the P4-treated groups. Further, the P4-specific inhibitor mifepristone (RU486) prevented porcine oocyte maturation, as represented by the reduced incidence (p < 0.05) of oocyte first polar body extrusions. RU486 affected maturation promoting factor (MPF) activity and maternal mRNA polyadenylation status. In general, these data show that P4 influences the cytoplasmic maturation of porcine oocytes, at least partially, by decreasing their polyadenylation, thereby altering maternal gene expression.

Reproductive factors and ovarian cancer risk in African-American women

PURPOSE

Reproductive characteristics, the most established ovarian cancer risk factors, differ markedly between African-American and white women. Studies in predominantly white populations suggest that associations between reproductive characteristics and ovarian cancer vary by timing of the events and menopause status. This analysis examined associations between number, duration, and timing of reproductive events and epithelial ovarian cancer among African-American women.

METHODS

Data from a multicenter case-control study of ovarian cancer in African-American women (641 cases/752 controls) were used to examine associations with oral contraceptive (OC) use and pregnancy characteristics. Odds ratios (ORs) and 95% confidence intervals (CIs) associated with reproductive characteristics were calculated with logistic regression models.

RESULTS

OC use (OR = 0.7, 95% CI 0.5-0.9), parity (OR = 0.5, 95% CI 0.3-0.6), and breastfeeding for >12 months (OR = 0.3, 95% CI 0.2-0.5) were inversely associated with ovarian cancer. More recent pregnancies and OC use had stronger associations with ovarian cancer than pregnancies or OC use that occurred earlier in life, especially among premenopausal women.

CONCLUSIONS

This study provides the first thorough documentation that pregnancy, breastfeeding, and OC use are inversely associated with ovarian cancer in African-American women, similar to what has been observed in white women. The associations with timing of the exposures suggest that these factors have both short- and long-term effects.

High-Fat Diet Promotion of Endometriosis in an Immunocompetent Mouse Model is Associated With Altered Peripheral and Ectopic Lesion Redox and Inflammatory Status

Endometriosis is a benign gynecological condition that causes considerable morbidity due to associated infertility, debilitating pelvic pain and inflammatory dysfunctions. Diet is a highly modifiable risk factor for many chronic diseases, but its contribution to endometriosis has not been extensively investigated, due partly to the paradoxical inverse association between obesity and disease incidence. Nevertheless, chronic exposure to dietary high-fat intake has been linked to greater systemic inflammation and oxidative stress, both features of women with endometriosis. Here, we evaluated the effects of a high-fat diet (HFD) (45% fat kcal) on endometriosis progression using an immunocompetent mouse model where ectopic lesion incidence was induced in wild-type recipients by ip administration of endometrial fragments from transcription factor Krüppel-like factor 9-null donor mice. We show that HFD significantly increased ectopic lesion numbers in recipient mice with no significant weight gain and modifications in systemic ovarian steroid hormone and insulin levels, relative to control diet-fed (17% fat kcal) mice. HFD promotion of lesion establishment was associated with reductions in stromal estrogen receptor 1 isoform and progesterone receptor expression, increased F4/80-positive macrophage infiltration, higher stromal but not glandular epithelial proliferation, and enhanced expression of proinflammatory and prooxidative stress pathway genes. Lesion-bearing HFD-fed mice also displayed higher peritoneal fluid TNFα and elevated local and systemic redox status than control diet-fed counterparts. Our results suggest that HFD intake exacerbates endometriosis outcome in the absence of ovarian dysfunction and insulin resistance in mice and warrants further consideration with respect to clinical management of endometriosis progression and recurrence in nonobese patients.

Ovarian hormones ameliorate memory impairment, cholinergic deficit, neuronal apoptosis and astrogliosis in a rat model of Alzheimer's disease

Ovarian hormones, including progesterone (P4) and 17 β-estradiol (E2), have been shown to affect memory functions; however, the underlying mechanism whereby ovarian hormone replacement therapy may decrease the risk of Alzheimer's disease (AD) is currently unclear. The present study aimed to investigate the effects of P4 and E2 on spatial and learning memory in an ovariectomized rat model of AD. β-amyloid (Aβ) or saline were stereotaxically injected into the hippocampus of the rats and, after 1 day, ovariectomy or sham operations were performed. Subsequently, the rats were treated with P4 alone, E2 alone, or a combination of P4 and E2. Treatment with E2 and/or P4 was shown to improve the learning and memory functions of the rats, as demonstrated by the Morris water maze test. In addition, treatment with E2 and P4 was associated with increased expression levels of choline acetyltransferase and 5-hydroxytryptamine receptor 2A (5-HT2A), and decreased expression levels of the glial fibrillary acidic protein in the hippocampus of the rats. Furthermore, E2 and P4 treatment significantly attenuated neuronal cell apoptosis, as demonstrated by terminal deoxynucleotidyl transferase dUTP nick end labeling assays; thus suggesting that the ovarian hormones were able to protect against Aβ-induced neuronal cell toxicity. The results of the present study suggested that the neuroprotective effects of P4 and E2 were associated with amelioration of the cholinergic deficit, suppression of apoptotic signals and astrogliosis, and upregulation of 5-HT2A expression levels. Therefore, hormone replacement therapy may be considered an effective strategy for the treatment of patients with cognitive disorders and neurodegenerative diseases.

Progesterone regulates the proliferation of breast cancer cells - in vitro evidence

Reports state that surgery performed at different phases of the menstrual cycle may significantly affect breast cancer treatment outcome. From previous studies, we identified differentially expressed genes in each menstrual cycle phase by microarray, then subjected them to functional in vitro analyses. Microarray studies disclosed genes that are upregulated in the luteal phase and follicular phase. TOB-1 is a tumor suppressor gene and was expressed exclusively in the luteal phase in our microarray study. Therefore, we further functionally characterized the protein product of TOB-1 in vitro. To our knowledge, no studies have yet been conducted on reactive oxygen species-regulated tumor suppressor interactions in accordance with the biphasic nature of progesterone. This work demonstrates that progesterone can produce reactive oxygen species in MCF-7 cells and that TOB-1 exerts a series of non-genomic interactions that regulate antiproliferative activity by modulating the antioxidant enzyme superoxide dismutase. Furthermore, this study implicates PTEN as an interacting partner for TOB-1, which may regulate the downstream expression of cell cycle control protein p27 via multiple downstream signaling pathways of progesterone through a progesterone receptor, purely in a time- and concentration-dependent manner. These results support the hypothesis that surgery conducted during the luteal phase of the menstrual cycle may facilitate improved patient survival.

Protective Effect of Progesterone during Pregnancy against Ovarian Cancer

There have been several epidemiologic studies supporting the protective role of pregnancy, although the mechanism is not clear. High level of progesterone, which is crucial in maintaining pregnancy, has been supposed to be one of the causative factors. Progesterone is produced at the corpus luteum in the early pregnancy and the placenta in the late pregnancy period. In several experimental studies, progesterone was reported to induce apoptosis of ovarian cancer cells through intrinsic and extrinsic pathways. In addition, progesterone has been shown to exert its anticancer effect through genomic and non-genomic action. The objective of this review is to discuss the protective mechanism of pregnancy against ovarian cancer focusing on the steroid hormone, progesterone.

Progesterone induces apoptosis of insulin-secreting cells: insights into the molecular mechanism

Progesterone has been associated with the development of gestational diabetes (GD) due to the enhancement of insulin resistance. As β-cell apoptosis participates in type 1 and type 2 diabetes pathophysiology, we proposed the hypothesis that progesterone might contribute to the development of GD through a mechanism that also involves β-cell death. To address this question, RINm5F insulin-producing cells were incubated with progesterone (25-100 μM), in the presence or absence of α-tocopherol (40 μM). After 24 or 48 h, membrane integrity and DNA fragmentation were analyzed by flow cytometry. Caspase activity was used to identify the mode of cell death. The involvement of endoplasmic reticulum stress in the action of progesterone was investigated by western blotting. Oxidative stress was measured by 2',7'-dichlorofluorescein diacetate (DCFDA) oxidation. Isolated rat islets were used in similar experiments in order to confirm the effect of progesterone in primary β-cells. Incubation of RINm5F cells with progesterone increased the number of cells with loss of membrane integrity and DNA fragmentation. Progesterone induced generation of reactive species. Pre-incubation with α-tocopherol attenuated progesterone-induced apoptosis. Western blot analyses revealed increased expression of CREB2 and CHOP in progesterone-treated cells. Progesterone caused apoptotic death of rat islet cells and enhanced generation of reactive species. Our results show that progesterone can be toxic to pancreatic β-cells through an oxidative-stress-dependent mechanism that induces apoptosis. This effect may contribute to the development of GD during pregnancy, particularly under conditions that require administration of pharmacological doses of this hormone.

Estrogen combined with progesterone decreases cell proliferation and inhibits the expression of Bcl-2 via microRNA let-7a and miR-34b in ovarian cancer cells

PURPOSE

This study evaluated the effect of estrogen (E(2)), progesterone (P4), and the combination of them (E(2) + P4) on survival rate, apoptosis, and the expressions of Bcl-2, hsa-let-7a and has-miR-34b in primary ovarian cancer cells to provide new clues for the clinical treatments of ovarian cancer.

METHODS

The primary ovarian cancer cells from 60 cases of clinical ovarian cancer tissues were isolated and then cultured. The survival rate of ovarian cancer cells after the treatment of E(2), P4 and E(2) + P4 was analyzed by MTT assay. Cell apoptosis rate and cell cycle were measured by FACS analysis. Moreover, the relative abundance of Bcl-2 and microRNAs (let-7a, miR-34b) expressions were detected by quantitative real-time PCR (qRT-PCR) and Western blotting.

RESULTS

Low concentrations of estrogen (10(-10), 10(-8), 10(-6 )mol/L) did not affect the proliferation of ovarian cancer cells. However, the high concentration of estrogen (10(-4 )mol/L) inhibited survival rate of ovarian cancer cells. Progesterone (10(-4 )mol/L) inhibited the proliferation of cancer cells. The combination of estrogen and progesterone significantly inhibited the survival rate of ovarian cancer cells with a time- and dose-dependent manner. High concentration of estrogen combined with progesterone (E(2) + P4) induced apoptosis of ovarian cancer cells. E(2) + P4 promoted the expression of let-7a and miR-34b and reduced the expression of Bcl-2 in ovarian cancer cells. When the expression of let-7a or/and miR-34b was inhibited using miRNA inhibitors, E(2) + P4 treatment did not change the protein level of Bcl-2.

CONCLUSION

E(2) + P4 significantly inhibited the cell survival, promoted the cell apoptosis, induced the expression of let-7a and miR-34b, and reduced the expression of Bcl-2 in ovarian cancer cells.

Progesterone enhances calcitriol antitumor activity by upregulating vitamin D receptor expression and promoting apoptosis in endometrial cancer cells

Human studies suggest that progesterone and calcitriol may prove beneficial in preventing or inhibiting oncogenesis, but the underlying mechanism is not fully understood. The current study investigates the effects of progesterone, calcitriol, and their combination on immortalized human endometrial epithelial cells and endometrial cancer cells and identifies their targets of action. Combination treatment with both agents enhanced vitamin D receptor expression and inhibited cell proliferation through caspase-3 activation and induction of G0-G1 cell-cycle arrest with associated downregulation of cyclins D1 and D3 and p27 induction. We used mass spectrometry-based proteomics to measure protein abundance differences between calcitriol-, progesterone-, or combination-exposed endometrial cells. A total of 117 proteins showed differential expression among these three treatments. Four proteins were then selected for validation studies: histone H1.4 (HIST1H1E), histidine triad nucleotide-binding protein 2 (HINT2), IFN-induced, double-stranded RNA-activated protein kinase (EIF2AK2), and Bcl-2-associated X protein (BAX). Abundance levels of selected candidates were low in endometrial cancer cell lines versus the immortalized endometrial epithelial cell line. All four proteins displayed elevated expression in cancer cells upon exposure to calcitriol, progesterone, or the combination. Further BAX analysis through gain- or loss-of-function experiments revealed that upregulation of BAX decreased cell proliferation by changing the BAX:BCL-2 ratio. Knockdown of BAX attenuated progesterone- and calcitriol-induced cell growth inhibition. Our results showed that progesterone and calcitriol upregulate the expression of BAX along with other apoptosis-related proteins, which induce inhibition of endometrial cancer cell growth by apoptosis and cell-cycle arrest.

Progesterone and calcitriol attenuate inflammatory cytokines CXCL1 and CXCL2 in ovarian and endometrial cancer cells

Cytokines/chemokines are key players in cancer-related inflammation. Increasing evidence suggests that chemokines produced by tumor cells are the mediators of metastasis. Thus, agents that can downregulate chemokines expression have potential against cancer metastasis. We have previously shown inhibition of ovarian and endometrial cancer cell growth with progesterone and calcitriol. In the present study, we evaluated the effect of these two agents on the expression of inflammatory genes. Using a RT-PCR array of inflammatory cytokines/chemokines and their receptors, we found a marked attenuation of CXCL1 and CXCL2 (GRO-α and -β) in cancer cells by both treatments. Knockdown of NFκB resulted in a reduced expression of CXCL1 and CXCL2 and the inhibitory effect of progesterone and calcitriol on the expression of chemokines was abrogated in NFκB-silenced cancer cells. Silencing of IκBα increased the expression of CXCL1 and CXCL2 in cancer cells, which can be attributed to the increased activation of NFκB-p65, caused by the lack of its inhibitor. Progesterone and calcitriol-induced inhibition was abolished in IκBα-knockdown cells. Our results demonstrate that suppression of IκBα phosphorylation by progesterone and calcitriol contributes to the reduced expression of CXCL1 and CXCL2. Downregulation of CXCL1 and CXCL2 was associated with a marked inhibition of metastasis-promoting genes. Overall, our results indicate that progesterone and calcitriol inhibit IκBα phosphorylation, NFκB activation, and the expression of NFκB regulated metastasis promoting genes. These results provide attractive data for the possible use of progesterone and calcitriol in the management of endometrial and ovarian tumors.

Upsides and downsides of reactive oxygen species for cancer: the roles of reactive oxygen species in tumorigenesis, prevention, and therapy

SIGNIFICANCE

Extensive research during the last quarter century has revealed that reactive oxygen species (ROS) produced in the body, primarily by the mitochondria, play a major role in various cell-signaling pathways. Most risk factors associated with chronic diseases (e.g., cancer), such as stress, tobacco, environmental pollutants, radiation, viral infection, diet, and bacterial infection, interact with cells through the generation of ROS.

RECENT ADVANCES

ROS, in turn, activate various transcription factors (e.g., nuclear factor kappa-light-chain-enhancer of activated B cells [NF-κB], activator protein-1, hypoxia-inducible factor-1α, and signal transducer and activator of transcription 3), resulting in the expression of proteins that control inflammation, cellular transformation, tumor cell survival, tumor cell proliferation and invasion, angiogenesis, and metastasis. Paradoxically, ROS also control the expression of various tumor suppressor genes (p53, Rb, and PTEN). Similarly, γ-radiation and various chemotherapeutic agents used to treat cancer mediate their effects through the production of ROS. Interestingly, ROS have also been implicated in the chemopreventive and anti-tumor action of nutraceuticals derived from fruits, vegetables, spices, and other natural products used in traditional medicine.

CRITICAL ISSUES

These statements suggest both "upside" (cancer-suppressing) and "downside" (cancer-promoting) actions of the ROS. Thus, similar to tumor necrosis factor-α, inflammation, and NF-κB, ROS act as a double-edged sword. This paradox provides a great challenge for researchers whose aim is to exploit ROS stress for the development of cancer therapies.

FUTURE DIRECTIONS

the various mechanisms by which ROS mediate paradoxical effects are discussed in this article. The outstanding questions and future directions raised by our current understanding are discussed.