Mechanistic Effects of Estrogens on Breast Cancer

Randomized trials of estrogen-alone and breast cancer incidence: a meta-analysis

PURPOSE

In the Women's Health initiative (WHI) randomized clinical trial, conjugated equine estrogen (CEE)-alone significantly reduced breast cancer incidence (P = 0.005). As cohort studies had opposite findings, other randomized clinical trials were identified to conduct a meta-analysis of estrogen-alone influence on breast cancer incidence.

METHODS

We conducted literature searches on randomized trials and: estrogen, hormone therapy, and breast cancer, and searches from a prior meta-analysis and reviews. In the meta-analysis, for trials with published relative risks (RR) and 95% confidence intervals (CI), each log-RR was multiplied by weight = 1/V, where V = variance of the log-RR, and V was derived from the corresponding 95% CI. For smaller trials with only breast cancer numbers, the corresponding log-RR = (O - E)/weight, where O is the observed case number in the oestrogen-alone group and E the corresponding expected case number, E = nP.

RESULTS

Findings from 10 randomized trials included 14,282 participants and 591 incident breast cancers. In 9 smaller trials, with 1.2% (24 of 2029) vs 2.2% (33 of 1514) randomized to estrogen-alone vs placebo (open label, one trial) (RR 0.65 95% CI 0.38-1.11, P = 0.12). For 5 trials evaluating estradiol formulations, RR = 0.63 95% CI 0.34-1.16, P = 0.15. Combining the 10 trials, 3.6% (262 of 7339) vs 4.7% (329 of 6943) randomized to estrogen-alone vs placebo (overall RR 0.77 95% CI 0.65-0.91, P = 0.002).

CONCLUSION

The totality of randomized clinical trial evidence supports a conclusion that estrogen-alone use significantly reduces breast cancer incidence.

Postmenopausal endometriosis: a challenging condition beyond menopause

IMPORTANCE AND OBJECTIVE

Postmenopausal endometriosis is a complex condition that challenges the conventional belief that endometriosis resolves with menopause. Despite the cessation of menstruation, a subset of women continues to experience or develop endometriosis-related symptoms during the postmenopausal period. Thus, this review aimed to shed light on postmenopausal endometriosis, exploring its clinical features, diagnostic considerations, management approaches, and the potential impact on women's health.

METHODS

PubMed/Medline, Scopus, and Web of Science databases were used for the research, with only articles in English language, using the following terms: "postmenopausal endometriosis," "menopause," "management," "treatment," and "quality of life," from inception to 2023.

DISCUSSION AND CONCLUSION

The clinical features of postmenopausal endometriosis include persistent or recurrent pelvic pain, dyspareunia, bowel, or urinary symptoms and, occasionally, abnormal vaginal bleeding. The absence of menstrual cycles presents a diagnostic challenge, as the traditional diagnostic criteria for endometriosis rely on menstrual patterns. Visual cues may be less evident, and the symptoms often overlap with other gynecological conditions, necessitating a thorough evaluation to differentiate postmenopausal endometriosis from other potential causes. Management approaches for postmenopausal endometriosis encompass surgical intervention, hormonal therapies, pain management, and individualized care. Postmenopausal endometriosis significantly impacts the quality of life, sexual health, and long-term well-being of women. Understanding the clinical features, diagnostic challenges, and management approaches of postmenopausal endometriosis is crucial for healthcare professionals to provide effective care and to improve the quality of life of women affected by this condition.

The 100 top-cited articles in menopausal syndrome: a bibliometric analysis

BACKGROUND

Significant scientific research has been conducted concerning menopausal syndrome(MPS), yet few bibliometric analyses have been performed. Our aim was to recognise the 100 most highly cited published articles on MPS and to analytically evaluate their key features.

METHODS

To identify the 100 most frequently cited articles, a search was conducted on Web of Science using the term 'menopausal syndrome'. Articles that matched the predetermined criteria were scrutinised to obtain the following data: citation ranking, year of publication, publishing journal, journal impact factor, country of origin, academic institution, authors, study type, and keywords.

RESULTS

The publication period is from January 1, 2000, to August 31, 2022. The maximum number of citations was 406 and in 2012. The median citations per year was 39.70. Most of the articles focused on treatment and complications. These articles were published in 36 different journals, with the Journal of MENOPAUSE having published the greatest number (14%). Forty-eight articles (48%) were from the United States, with the University of Pittsburgh being the leading institute (9%). Joann E. Manson was the most frequent first author (n = 6). Observational studies were the most frequently conducted research type (n = 53), followed by experimental studies (n = 33). Keyword analysis identified classic research topics, including genitourinary syndrome of menopause, bone mineral density (BMD), and anti-mullerian hormone (AMH) loci.

CONCLUSION

Using bibliometrics, we conducted an analysis to identify the inadequacies, traditional focal points, and potential prospects in the study of MPS across current scientific areas. Treatment and complications are at the core of MPS research, whereas prediction and biomarkers have less literature of high quality. There is a necessity for innovative analytical metrics to measure the real effect of these papers with a high level of citation on clinical application.

Therapeutic evolution in HR+/HER2- breast cancer: from targeted therapy to endocrine therapy

Breast cancer, a complex and varied disease, has four distinct subtypes based on estrogen receptor and human epidermal growth factor receptor 2 (HER2) levels, among which a significant subtype known as HR+/HER2-breast cancer that has spurred numerous research. The prevalence of breast cancer and breast cancer-related death are the most serious threats to women's health worldwide. Current progress in treatment strategies for HR+/HER2-breast cancer encompasses targeted therapy, endocrine therapy, genomic immunotherapy, and supplementing traditional methods like surgical resection and radiotherapy. This review article summarizes the current epidemiology of HR+/HER2-breast cancer, introduces the classification of HR+/HER2-breast cancer and the commonly used treatment methods. The mechanisms of action of various drugs, including targeted therapy drugs and endocrine hormone therapy drugs, and their potential synergistic effects are deeply discussed. In addition, clinical trials of these drugs that have been completed or are still in progress are included.

Anastrozole Protects against Human Coronavirus Infection by Ameliorating the Reactive Oxygen Species-Mediated Inflammatory Response

The common human coronavirus (HCoV) exhibits mild disease with upper respiratory infection and common cold symptoms. HCoV-OC43, one of the HCoVs, can be used to screen drug candidates against SARS-CoV-2. We determined the antiviral effects of FDA/EMA-approved drug anastrozole (AZ) on two human coronaviruses, HCoV-OC43 and HCoV-229E, using MRC-5 cells in vitro. The AZ exhibited antiviral effects against HCoV-OC43 and HCoV-229E infection. Subsequent studies focused on HCoV-OC43, which is related to the SARS-CoV-2 family. AZ exhibited anti-viral effects and reduced the secretion of inflammatory cytokines, TNF-α, IL-6, and IL-1β. It also inhibited NF-κB translocation to effectively suppress the inflammatory response. AZ reduced intracellular calcium and reactive oxygen species (ROS) levels, including mitochondrial ROS and Ca2+, induced by the virus. AZ inhibited the expression of NLRP3 inflammasome components and cleaved IL-1β, suggesting that it blocks NLRP3 inflammasome activation in HCoV-OC43-infected cells. Moreover, AZ enhanced cell viability and reduced the expression of cleaved gasdermin D (GSDMD), a marker of pyroptosis. Overall, we demonstrated that AZ exhibits antiviral activity against HCoV-OC43 and HCoV-229E. We specifically focused on its efficacy against HCoV-OC43 and showed its potential to reduce inflammation, inhibit NLRP3 inflammasome activation, mitigate mitochondrial dysfunction, and suppress pyroptosis in infected cells.

'Tis but a scratch: a critical review of the Women's Health Initiative evidence associating menopausal hormone therapy with the risk of breast cancer

ABSTRACT

Use of menopausal hormone therapy (HT) fell precipitously after 2002, largely as a result of the Women's Health Initiative's report claiming that the combination of conjugated equine estrogen (CEE) and medroxyprogesterone acetate increased breast cancer risk and did not improve quality of life. More recently, Women's Health Initiative (WHI) publications acknowledge HT as the most effective treatment for managing menopausal vasomotor symptoms and report that CEE alone reduces the risk of breast cancer by 23% while reducing breast cancer death by 40%. Their sole remaining concern is a small increase in breast cancer incidence with CEE and medroxyprogesterone acetate (1 per 1,000 women per year) but with no increased risk of breast cancer mortality. This article closely examines evidence that calls even this claim of breast cancer risk into serious question, including the WHI's reporting of nonsignificant results as if they were meaningful, a misinterpretation of its own data, and the misleading assertion that the WHI's findings have reduced the incidence of breast cancer in the United States. A generation of women has been deprived of HT largely as a result of this widely publicized misinterpretation of the data. This article attempts to rectify this misunderstanding, with the goal of helping patients and physicians make informed joint decisions about the use of HT.

Activation of kappa opioid receptor (KOR) inhibits estrogen receptor (ER)-positive breast cancer through the KOR-ER-XBP1 pathway

Opioids are commonly used in patients with breast cancer (BC), both for perioperative analgesia and for the relief of chronic cancer pain. Studies have suggested a potential association of opioid receptors (ORs) with the prognosis of BC patients. However, the exact roles of different ORs remain poorly understood. In this study, we found that κ opioid receptor (KOR) was the only OR (among the four types of ORs) that was significantly decreased in BC tumor tissues compared with peritumoral normal tissues. In addition, decreased expression of KOR correlated with poor clinical outcomes in patients with estrogen receptor (ER)-positive BC. In vitro studies confirmed the anti-tumor effects of KOR agonists in ER-positive MCF-7 and T47D cells by showing that activation of KOR significantly inhibited cellular proliferation and promoted apoptosis. Using Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein-protein interaction network (PPI) analysis, we found that KOR-ER-XBP1 was the potential downstream signaling pathway mediating the anti-tumor effects of KOR agonist. Finally, the role of XBP1 was confirmed as KOR activation-induced increase in the proliferative and monoclonal formation abilities of ER-positive BC cells were both significantly abolished after silencing of XBP1. These findings provide us a better understanding of the roles of different ORs in BC, identifying KOR agonists as better opioids than traditional μ opioid receptor (MOR) agonists for providing analgesia in ER-positive BC patients owing to their association with better prognosis.

The Women's Health Initiative randomized trials of menopausal hormone therapy and breast cancer: findings in context

IMPORTANCE AND OBJECTIVE

The menopausal hormone therapy (MHT) association with breast cancer has been controversial for more than 40 years. Most recently, findings from cohort studies have been discordant compared with those from the Women's Health Initiative (WHI) randomized trials. In cohort studies, both estrogen therapy and estrogen plus progestin were associated with higher breast cancer incidence. In contrast, in the WHI randomized trials, findings for estrogen plus progestin are concordant with cohort study reports, whereas estrogen therapy significantly reduced breast cancer incidence. In addition, concerns have been raised regarding the WHI findings from both trials. In this report, we briefly summarize findings for MHT on breast cancer from cohort studies and the WHI randomized trials. The report focus is addressing, point-by-point, concerns raised regarding the WHI findings.

METHODS

For cohort studies, we relied on the latest findings from (1) the meta-analysis of the Collaborative Group on Hormonal Factors in Breast Cancer and (2) the Million Women's Study. To identify commentaries and editorials, "Menopause" and "Climacteric" were searched from 2002 to present; PubMed and Google Scholar were searched for commentaries, editorials, and breast cancer, MHT, estrogen, conjugated equine estrogen, estradiol, "hormone replacement therapy," and "HRT."

DISCUSSION AND CONCLUSIONS

Thirty commentaries challenging WHI findings were identified. All were reviewed, and issues needing response were identified. Findings from the meta-analysis from the Collaborative Group on Hormonal Factors in Breast Cancer and the Million Women Study were summarized and compared with finding in the two WHI randomized trials evaluating estrogen therapy and estrogen plus progestin. Based on the randomized clinical trials, estrogen therapy, for women with prior hysterectomy, decreases breast cancer incidence and mortality. In contrast, estrogen plus progestin increases breast cancer incidence, which persists through two decades. Women considering estrogen plus progestin use for vasomotor symptoms should understand the breast cancer risk.

Esr1 but Not CYP19A1 Overexpression in Mammary Epithelial Cells during Reproductive Senescence Induces Pregnancy-Like Proliferative Mammary Disease Responsive to Anti-Hormonals

Molecular-level analyses of breast carcinogenesis benefit from vivo disease models. Estrogen receptor 1 (Esr1) and cytochrome P450 family 19 subfamily A member 1 (CYP19A1) overexpression targeted to mammary epithelial cells in genetically engineered mouse models induces largely similar rates of proliferative mammary disease in prereproductive senescent mice. Herein, with natural reproductive senescence, Esr1 overexpression compared with CYP19A1 overexpression resulted in significantly higher rates of preneoplasia and cancer. Before reproductive senescence, Esr1, but not CYP19A1, overexpressing mice are tamoxifen resistant. However, during reproductive senescence, Esr1 mice exhibited responsiveness. Both Esr1 and CYP19A1 are responsive to letrozole before and after reproductive senescence. Gene Set Enrichment Analyses of RNA-sequencing data sets showed that higher disease rates in Esr1 mice were accompanied by significantly higher expression of cell proliferation genes, including members of prognostic platforms for women with early-stage hormone receptor-positive disease. Tamoxifen and letrozole exposure induced down-regulation of these genes and resolved differences between the two models. Both Esr1 and CYP19A1 overexpression induced abnormal developmental patterns of pregnancy-like gene expression. This resolved with progression through reproductive senescence in CYP19A1 mice, but was more persistent in Esr1 mice, resolving only with tamoxifen and letrozole exposure. In summary, genetically engineered mouse models of Esr1 and CYP19A1 overexpression revealed a diversion of disease processes resulting from the two distinct molecular pathophysiological mammary gland-targeted intrusions into estrogen signaling during reproductive senescence.

Managing Bone Health in Breast Cancer

OBJECTIVE

Osteoporosis is a common condition that can be caused or exacerbated by estrogen deficiency.

METHODS

This narrative review will discuss optimizing bone health in the setting of adjuvant endocrine treatments for hormone receptor-positive breast cancer and the current use of antiresorptive agents as adjuvant therapy and as bone modifying agents.

RESULTS

Adjuvant endocrine treatments for hormone receptor-positive breast cancer (tamoxifen and aromatase inhibitors) affect bone health. The exact effect depends on the agent used and the menopausal state of the woman. Antiresorptive medications for osteoporosis, bisphosphonates and denosumab, lower the risk of bone loss from aromatase inhibitors. Use of bisphosphonates as adjuvant treatment in breast cancer, regardless of hormone receptor status, is increasing because of benefits seen to cancer relapse and survival.

CONCLUSION

Optimizing bone health in women with breast cancer during and after cancer treatment is informed by an understanding of breast cancer treatment and its skeletal effect.