Molecular mechanisms of tamoxifen-associated endometrial cancer (Review)

Impact of estradiol in inducing endometrial cancer using RL95-2

BACKGROUND

Endometrial cancer is the most common gynecological malignancy that originates from the inner lining of the uterus and predominantly affects postmenopausal women. Prolonged exposure to estrogen, family history of endometrial cancer, obesity, and hormonal imbalance are some of the risk factors associated with endometrial cancer. In our study, we investigated the effect of estradiol, a potent form of estrogen at various concentrations on endometrial cell line RL95-2.

METHODS

Endometrial cell RL95-2 were cultured in DMEM medium with optimal conditions required to maintain the cells. MTT assay and colony formation assay were further performed after treating the cells with different concentrations of estradiol (1, 10, and 100 nM) and TAM (100 nM). Moreover, the effect of genes regulated by estradiol was also examined using microarray and validated using real-time polymerase chain reaction (qRT-PCR).

RESULTS

Time-dependent MTT assay shows a significant change in the ability of the cells to survive relative to concentrations. Colony formation was found to be directly proportional to the concentration of the estradiol (p < 0.05). Among genes, MMP14 (p = 0.03), SPARCL1 (p = 0.005), and CLU (p = 0.06) showed a significant up-regulation in their expression after estradiol treatment while NRN1 (p < 0.001) showed significant downregulation in expression pattern compared to control. However, the TAM treatment was found to be significantly effective after 72 h (p < 0.001) compared to control and 100 nM E2 (p = 0.0206).

CONCLUSION

Our study suggests that estradiol significantly contributes to regulating the viability, colony formation, and expression of genes associated with endometrial cancer.

The challenge of survivors of gynecological carcinomas: a retrospective study on occurrence of second tumors

OBJECTIVE

To clarify the epidemiologic characteristics and risk of other tumors in survivors of gynecological tumors.

MATERIALS AND METHODS

This is a retrospective study based on the Surveillance, Epidemiology, and End Results database (SEER).

RESULTS

The morbidity of other malignant tumors in patients with gynecological cancer was 8.07%. The most common subsequent tumors are breast, lung, colorectal, thyroid, and bladder cancers. Taking the incidence rate of the general population as reference, the second tumor with the highest relative risk in patients with cervical cancer is vulvar cancer. Bladder cancer is the second tumor with the highest relative risk value both in patients with corpus and ovarian cancer. The median period from the diagnosis of the initial tumor to the diagnosis of the second tumor was 5 years. Most patients with other tumors following gynecological cancer showed worse prognosis than patients with gynecological tumors only. However, thyroid cancer following ovarian cancer is a protective factor in survival.

CONCLUSION

Patients with gynecological tumors have a significantly higher risk of malignant tumors in other systems compared to ordinary population. It is necessary to be vigilant against subsequent high-risk tumors and tumors with poor prognosis within 5 years of initial diagnosis.

Rare Mullerian adenosarcoma of the uterine cervix arising on a background of endometriosis: A diagnostic challenge with risk of malignant transformation-A case report and review of the current literature

Endometriosis may contribute to Mullerian adenosarcoma development but makes diagnosis challenging given similar symptoms. Survival benefit has not been definitively shown for chemotherapy, hormonal therapy, or radiotherapy, consolidating surgery as the mainstay treatment. Local excision may be a treatment option for patients with confined tumors wishing to preserve their fertility.

Breast cancer therapies reduce risk of Alzheimer's disease and promote estrogenic pathways and action in brain

Worldwide, an ever-increasing number of women are prescribed estrogen-modulating therapies (EMTs) for the treatment of breast cancer. In parallel, aging of the global population of women will contribute to risk of both breast cancer and Alzheimer's disease. To address the impact of anti-estrogen therapies on risk of Alzheimer's and neural function, we conducted medical informatic and molecular pharmacology analyses to determine the impact of EMTs on risk of Alzheimer's followed by determination of EMT estrogenic mechanisms of action in neurons. Collectively, these data provide both clinical and mechanistic data indicating that select EMTs exert estrogenic agonist action in neural tissue that are associated with reduced risk of Alzheimer's disease while simultaneously acting as effective estrogen receptor antagonists in breast.

Tamoxifen use and risk of endometrial cancer in breast cancer patients: A systematic review and dose-response meta-analysis

BACKGROUND

Worse prognosis of endometrial cancers (EC) in tamoxifen-treated women compared to non-tamoxifen-treated women been proposed. The relationship between tamoxifen treatment of breast cancer (BC) and the risk of EC is controversial and there is no agreement between publication results on this issue (the answer to all comments provided in the page 2 of manuscript). The aim of this study is investigation the association between tamoxifen treatment and the risk of EC in patients with BC.

METHODS AND RESULTS

We conducted a comprehensive search with related keywords in MEDLINE/PubMed, SCOPUS, and Web of Science databases until April 16, 2022. Random-effects model (DerSimonian and Laird) was used to pool risk ratios (RRs) with 95% confidence intervals (CIs) of EC. Dose, cumulative dose, and duration-response analysis were performed in linear and non-linear states. Twenty-six studies reported a relation between tamoxifen treatment and risk of EC in patients with BC. Results showed a direct relationship between tamoxifen use and EC (RR: 2.03, 95% CI: 1.68-2.45; I2:76%). By increase the age of participants, the risk of EC was decrease (coef = -.0206), although this was not statistically significant (p = .37). Linear dose-response model indicated a direct significant association between dose and duration use of tamoxifen and EC (dose: exe(b) = 1.019, p = .001; duration: exe(b) = 1.014, p = .001). Non-linear dose-response analysis confirmed linear analysis.

CONCLUSION

This study highlights that tamoxifen use is a significant risk factor related to the incidence of EC in patients with BC.

Regulation of progesterone receptor expression in endometriosis, endometrial cancer, and breast cancer by estrogen, polymorphisms, transcription factors, epigenetic alterations, and ubiquitin-proteasome system

The uterus and breasts are hormone-responsive tissues. Progesterone and estradiol regulate gonadotropin secretion, prepare the endometrium for implantation, maintain pregnancy, and regulate the differentiation of breast tissue. Dysregulation of these hormones causes endometriosis, endometrial cancer, and breast cancer, damaging the physical and mental health of women. Emerging evidence has shown that progesterone resistance or elevated progesterone activity is the primary hormonal substrate of these diseases. Since progesterone acts through its specific nuclear receptor, the abnormal expression of the progesterone receptor (PR) dysregulates progesterone function. This review discusses the regulatory mechanisms of PR expression in patients with endometriosis, and endometrial or breast cancer, including estrogen, polymorphisms, transcription factors, epigenetics, and the ubiquitin-proteasome system. (1) Estrogen promotes the expression of PRA (a PR isoform) mRNA and protein through the interaction of estrogen receptors (ERs) and Sp1 with half-ERE/Sp1 binding sites. ERs also affect the binding of Sp1 and Sp1 sites to promote the expression of PRB (another PR isoform)(2) PR polymorphisms, mainly PROGINS and + 331 G/A polymorphism, regulate PR expression by affecting DNA methylation and transcription factor binding. (3) The influence of epigenetic alterations on PR expression occurs through DNA methylation, histone modification, and microRNA. (4) As one of the main protein degradation pathways in vivo, the ubiquitin-proteasome system (UPS) regulates PR expression by participating in protein degradation. These mechanisms may provide new molecular targets for diagnosing and treating endometriosis, endometrial, and breast cancer.

DOK7 CpG hypermethylation in blood leukocytes as an epigenetic biomarker for acquired tamoxifen resistant in breast cancer

BACKGROUND

Breast cancer (BC) is among the most common cause of cancer 10.4% and one of the leading causes of death among 20-50 years old women in the world. Tamoxifen drug is the first line therapy for BC however tamoxifen resistance (TR) has shown in 30-50% of cases that may face BC recurrence. Hence, TR early detection reduces BC recurrence and fatalities. The epigenetic alteration that happens by hypermethylation of tumor suppressor genes and hypomethylation of oncogenes has been suggested to be useful in early cancer or drug resistance diagnosis.

METHODS

This is the first study to investigate DOK7 CpG hypermethylation in blood leukocytes of 31 TR (ER+) BC compared to 29 tamoxifen sensitive BC to evaluate DOK7 as a potential TR biomarker. DNA was extracted from blood samples of all participants and MSRE-PCR and real-time PCR were used for quantification of CpG methylation alterations.

RESULTS

The means of DOK7 CpG hypermethylation were obtained as 85.03%, 29.1% and 57.34% in TR, TS and normal control respectively. Significant hypermethylation were found among TR vs. TS (p < 0.001), TS vs. normal (p < 0.001) and TR vs. normal controls (p < 0.03). Online databases expression and survival analysis of DOK7 showed increasing expression in TS groups vs. TR groups which have consistency with our methylation alteration results. The sensitivity and specificity of the TR epigenetic test were determined using ROC analysis showed 89.66% and 96.77% respectively and showed that 37.5% above hypermethylation is at risk for TR and breast cancer recurrence.

CONCLUSION

There is a significant difference in the methylation ratio of DOK7 between tamoxifen resistant and tamoxifen sensitive groups that may be useful in the early diagnosis of tamoxifen resistance in BC cases and cancer recurrence prevention.

Targeted Therapy and Personalized Medicine

Targeted therapy and personalized medicine are novel emerging disciplines of cancer research intended for treatment and prevention. One of the most significant advancements in modern oncology is the shift from an organ-centric strategy to a personalized strategy guided by deep molecular analysis. This shift in view, which focuses on the tumour's precise molecular changes, has paved the way for individualized treatment. Researchers and clinicians are using targeted therapies to select the best treatment available based on the molecular characterization of malignant cancer. In the treatment of a cancer, personalized medicine entails the use of genetic, immunological, and proteomic profiling to provide therapeutic alternatives as well as prognostic information about cancer. In this book, targeted therapies and personalized medicine have been covered for specific malignancies, including latest FDA-approved targeted therapies and it also sheds light on effective anti-cancer regimens and drug resistance. This will help to enhance our ability to conduct individualized health planning, make early diagnoses, and choose optimal medications for each cancer patient with predictable side effects and outcomes in a quickly evolving era. Various applications and tools' capacity have been improved for early diagnosis of cancer and the growing number of clinical trials that choose specific molecular targets reflects this predicament. Nevertheless, there are several limitations that must need to be addressed. Hence, in this chapter, we will discuss recent advancements, challenges, and opportunities in personalized medicine for various cancers, with a specific emphasis on target therapies in diagnostics and therapeutics.

Hormone replacement therapy alone or in combination with tamoxifen in women with thin endometrium undergoing frozen-thawed embryo transfer: A retrospective study

RESEARCH QUESTION

To investigate the effects of two protocols (hormone replacement therapy (HRT) alone or in combination with tamoxifen) on the endometrium and pregnancy outcome of patients with thin endometrium in frozen-thawed embryo transfer (FET) cycles.

DESIGN

A total of 465 infertile patients with thin endometrium who underwent FET between January 2020 to June 2021 at the Drum Tower Hospital affiliated with Nanjing University Medical School were retrospectively analyzed. A total of 187 patients were given tamoxifen in addition to HRT (TMXF-HRT group), whereas 278 patients were given only HRT (HRT group). Clinical data were compared between the two groups, including general characteristics, endometrial thickness, and clinical pregnancy outcomes.

RESULTS

There were no significant differences in baseline characteristics of all enrolled patients between two groups. Serum progesterone (P) was higher in HRT group than in the TMXF-HRT group (0.28 ± 0.53 ng/mL vs. 0.15 ± 0.25 ng/mL, P = 0.002). There was a significant increase in endometrial thickness in the TMXF-HRT group compared with the HRT group (OR: 1.54, 95% CI: 1.32-1.75, P < 0.001). There were no significant differences in the clinical pregnancy rate, embryo implantation rate, early miscarriage rate, or live birth rate between these two groups.

CONCLUSION

Although tamoxifen when used in combination with hormone replacement therapy can significantly increase endometrial thickness, it may not have a role in improving the pregnancy outcomes of patients with thin endometrium undergoing FET cycles.

The complex nature of heterogeneity and its roles in breast cancer biology and therapeutic responsiveness

Heterogeneity is a complex feature of cells and tissues with many interacting components. Depending on the nature of the research context, interacting features of cellular, drug response, genetic, molecular, spatial, temporal, and vascular heterogeneity may be present. We describe the various forms of heterogeneity with examples of their interactions and how they play a role in affecting cellular phenotype and drug responses in breast cancer. While cellular heterogeneity may be the most widely described and invoked, many forms of heterogeneity are evident within the tumor microenvironment and affect responses to the endocrine and cytotoxic drugs widely used in standard clinical care. Drug response heterogeneity is a critical determinant of clinical response and curative potential and also is multifaceted when encountered. The interactive nature of some forms of heterogeneity is readily apparent. For example, the process of metastasis has the properties of both temporal and spatial heterogeneity within the host, whereas each individual metastatic deposit may exhibit cellular, genetic, molecular, and vascular heterogeneity. This review describes the many forms of heterogeneity, their integrated activities, and offers some insights into how heterogeneity may be understood and studied in the future.

Discovery of Highly Functionalized 5-hydroxy-2H-pyrrol-2-ones That Exhibit Antiestrogenic Effects in Breast and Endometrial Cancer Cells and Potentiate the Antitumoral Effect of Tamoxifen

Tamoxifen improves the overall survival rate in hormone receptor-positive breast cancer patients. However, despite the fact that it exerts antagonistic effects on the ERα, it can act as a partial agonist, resulting in tumor growth in estrogen-sensitive tissues. In this study, highly functionalized 5-hydroxy-2H-pyrrol-2-ones were synthesized and evaluated by using ERα- and phenotype-based screening assays. Compounds 32 and 35 inhibited 17β-estradiol (E2)-stimulated ERα-mediated transcription of the luciferase reporter gene in breast cancer cells without inhibition of the transcriptional activity mediated by androgen or glucocorticoid receptors. Compound 32 regulated E2-stimulated ERα-mediated transcription by partial antagonism, whereas compound 35 caused rapid and non-competitive inhibition. Monitoring of 2D and 3D cell growth confirmed potent antitumoral effects of both compounds on ER-positive breast cancer cells. Furthermore, compounds 32 and 35 caused apoptosis and blocked the cell cycle of ER-positive breast cancer cells in the sub-G1 and G0/G1 phases. Interestingly, compound 35 suppressed the functional activity of ERα in the uterus, as demonstrated by the inhibition of E2-stimulated transcription of estrogen and progesterone receptors and alkaline phosphatase enzymatic activity. Compound 35 showed a relatively low binding affinity with ERα. However, its antiestrogenic effect was associated with an increased polyubiquitination and a reduced protein expression of ERα. Clinically relevant, a possible combinatory therapy with compound 35 may enhance the antitumoral efficacy of 4-hydroxy-tamoxifen in ER-positive breast cancer cells. In silico ADME predictions indicated that these compounds exhibit good drug-likeness, which, together with their potential antitumoral effects and their lack of estrogenic activity, offers a pharmacological opportunity to deepen the study of ER-positive breast cancer treatment.

Molecular Biomarker Expression in Window of Opportunity Studies for Oestrogen Receptor Positive Breast Cancer-A Systematic Review of the Literature

Simple Summary

Window of opportunity (WoO) trials allow the opportunity to assess the use of drugs in breast cancer research before treatment has commenced. The aim of this review of the literature is to review WoO trials in patients with oestrogen receptor-positive (ER+) breast cancer to help guide treatment. This will be useful for patients who receive drug treatment before surgery, or as an alternative to surgery in older, more frail adults.

Abstract

Window of opportunity (WoO) trials create the opportunity to demonstrate pharmacodynamic parameters of a drug in vivo and have increasing use in breast cancer research. Most breast cancer tumours are oestrogen receptor-positive (ER+), leading to the development of multiple treatment options tailored towards this particular tumour subtype. The aim of this literature review is to review WoO trials pertaining to the pharmacodynamic activity of drugs available for use in ER+ breast cancer in order to help guide treatment for patients receiving neoadjuvant and primary endocrine therapy. Five databases (EMBASE, Cochrane, MEDLINE, PubMed, Web of Science) were searched for eligible studies. Studies performed in treatment-naïve patients with histologically confirmed ER+ breast cancer were included if they acquired pre- and post-treatment biopsies, compared measurement of a proteomic biomarker between these two biopsies and delivered treatment for a maximum mean duration of 31 days. Fifteen studies were eligible for inclusion and covered six different drug classes: three endocrine therapies (ETs) including aromatase inhibitors (AIs), selective oestrogen receptor modulators (SERMs), selective oestrogen receptor degraders (SERDs) and three non-ETs including mTOR inhibitors, AKT inhibitors and synthetic oestrogens. Ki67 was the most frequently measured marker, appearing in all studies. Progesterone receptor (PR) and ER were the next most frequently measured markers, appearing five and four studies, respectively. All three of these markers were significantly downregulated in both AIs and SERDs; Ki67 alone was downregulated in SERMs. Less commonly assessed markers including pS6, pGSH3B, FSH and IGF1 were downregulated while CD34, pAKT and SHBG were significantly upregulated. There were no significant changes in the other biomarkers measured such as phosphate and tensin homolog (PTEN), Bax and Bcl-2.WoO studies have been widely utilised within the ER+ breast cancer subtype, demonstrating their worth in pharmacodynamic research. However, research remains focused upon routinely measured biomarkers such ER PR and Ki67, with an array of less common markers sporadically used.

Computational approaches to identify a novel binding site of BHPI on estrogen receptor alpha

3,3-bis(4-hydroxyphenyl)-7-methyl-1,3,dihydro-2H-indol-2-one (BHPI) is a biomodulator of Estrogen Receptor alpha (ERα) that targets ERα positive cancer cells by activating the unfolded protein response (UPR). BHPI induces strong and sustained activation of this pathway, eventually resulting in necrotic cell death. While much is known about how BHPI triggers the UPR leading to necrotic cell death, it is not known how BHPI binds to its putative molecular target, ERα. In an effort to identify the binding site of BHPI on ERα, molecular docking studies in AutoDock Vina were utilized. Unexpectedly, BHPI was found to dock more frequently and with significantly better binding affinity to a newly described surface pocket on the ERα ligand-binding domain, compared to the ligand-binding pocket. This work uncovers a novel binding site for small molecules on ERα that is not targeted by classical ligands, such as estrogen and tamoxifen, and may allow for the design of additional anti-cancer drugs that work in distinct ways.

Discovery and preclinical profile of LX-039, a novel indole-based oral selective estrogen receptor degrader (SERD)

We previously described the discovery of a novel indole series compounds as oral SERD for ER positive breast cancer treatment. Further SAR exploration focusing on substitutions on indole moiety of compound 12 led to the discovery of a clinical candidate LX-039. We report herein its profound anti-tumor activity, desirable ER antagonistic characteristics combined with favorable pharmacokinetic and preliminary safety properties. LX-039 is currently in clinical trial (NCT04097756).

In vitro breast cancer models for studying mechanisms of resistance to endocrine therapy

The development of endocrine resistance is a common reason for the failure of endocrine therapies in hormone receptor-positive breast cancer. This review provides an overview of the different types of in vitro models that have been developed as tools for studying endocrine resistance. In vitro models include cell lines that have been rendered endocrine-resistant by ex vivo treatment; cell lines with de novo resistance mechanisms, including genetic alterations; three-dimensional (3D) spheroid, co-culture, and mammosphere techniques; and patient-derived organoid models. In each case, the key discoveries, different analysis strategies that are suitable, and strengths and weaknesses are discussed. Certain recently developed methodologies that can be used to further characterize the biological changes involved in endocrine resistance are then emphasized, along with a commentary on the types of research outcomes that using these techniques can support. Finally, a discussion anticipates how these recent developments will shape future trends in the field. We hope this overview will serve as a useful resource for investigators that are interested in understanding and testing hypotheses related to mechanisms of endocrine therapy resistance.

Identifying molecular mediators of the relationship between body mass index and endometrial cancer risk: a Mendelian randomization analysis

BACKGROUND

Endometrial cancer is the most common gynaecological cancer in high-income countries. Elevated body mass index (BMI) is an established modifiable risk factor for this condition and is estimated to confer a larger effect on endometrial cancer risk than any other cancer site. However, the molecular mechanisms underpinning this association remain unclear. We used Mendelian randomization (MR) to evaluate the causal role of 14 molecular risk factors (hormonal, metabolic and inflammatory markers) in endometrial cancer risk. We then evaluated and quantified the potential mediating role of these molecular traits in the relationship between BMI and endometrial cancer using multivariable MR.

METHODS

Genetic instruments to proxy 14 molecular risk factors and BMI were constructed by identifying single-nucleotide polymorphisms (SNPs) reliably associated (P < 5.0 × 10-8) with each respective risk factor in previous genome-wide association studies (GWAS). Summary statistics for the association of these SNPs with overall and subtype-specific endometrial cancer risk (12,906 cases and 108,979 controls) were obtained from a GWAS meta-analysis of the Endometrial Cancer Association Consortium (ECAC), Epidemiology of Endometrial Cancer Consortium (E2C2) and UK Biobank. SNPs were combined into multi-allelic models and odds ratios (ORs) and 95% confidence intervals (95% CIs) were generated using inverse-variance weighted random-effects models. The mediating roles of the molecular risk factors in the relationship between BMI and endometrial cancer were then estimated using multivariable MR.

RESULTS

In MR analyses, there was strong evidence that BMI (OR per standard deviation (SD) increase 1.88, 95% CI 1.69 to 2.09, P = 3.87 × 10-31), total testosterone (OR per inverse-normal transformed nmol/L increase 1.64, 95% CI 1.43 to 1.88, P = 1.71 × 10-12), bioavailable testosterone (OR per natural log transformed nmol/L increase: 1.46, 95% CI 1.29 to 1.65, P = 3.48 × 10-9), fasting insulin (OR per natural log transformed pmol/L increase: 3.93, 95% CI 2.29 to 6.74, P = 7.18 × 10-7) and sex hormone-binding globulin (SHBG, OR per inverse-normal transformed nmol/L increase 0.71, 95% CI 0.59 to 0.85, P = 2.07 × 10-4) had a causal effect on endometrial cancer risk. Additionally, there was suggestive evidence that total serum cholesterol (OR per mg/dL increase 0.90, 95% CI 0.81 to 1.00, P = 4.01 × 10-2) had an effect on endometrial cancer risk. In mediation analysis, we found evidence for a mediating role of fasting insulin (19% total effect mediated, 95% CI 5 to 34%, P = 9.17 × 10-3), bioavailable testosterone (15% mediated, 95% CI 10 to 20%, P = 1.43 × 10-8) and SHBG (7% mediated, 95% CI 1 to 12%, P = 1.81 × 10-2) in the relationship between BMI and endometrial cancer risk.

CONCLUSIONS

Our comprehensive MR analysis provides insight into potential causal mechanisms linking BMI with endometrial cancer risk and suggests targeting of insulinemic and hormonal traits as a potential strategy for the prevention of endometrial cancer.

Temporal patterns of chronic disease incidence after breast cancer: a nationwide population-based cohort study

We conducted a retrospective cohort study to evaluate the temporal pattern of incidence of chronic conditions after developing breast cancer using a population-based national registry. We selected 84,969 women with newly diagnosed breast cancer between 2002 and 2016 and a 1:10 sample of age-matched non-breast cancer controls (N = 1,057,674). The main study exposure was incident breast cancer, considered as a time-varying exposure. The outcomes were incident cases of leukemia, endometrial cancer, myeloma, cardiomyopathy, osteoporosis, end stage renal disease (ESRD), pulmonary fibrosis, hypothyroidism, type 2 diabetes, hypertension and hyperlipidemia. The development of breast cancer was associated with a significantly increased risk of all outcomes analyzed except for ESRD and hypertension. The fully-adjusted risks of leukemia (HR 3.09; 95% CI 2.11–4.51), cardiomyopathy (HR 2.65; 95% CI 1.90–3.68), endometrial cancer (HR 3.53; 95% CI 2.76–4.53), hypothyroidism (HR 1.29; 95% CI 1.19–1.40), pulmonary fibrosis (HR 1.84; 95% CI 1.12–3.02), and hyperlipidemia (HR 1.24; 95% CI 1.20–1.28) remained significantly elevated after more than 5 years since diagnosis. Optimal care for breast cancer survivors requires close collaboration between oncologists and allied health care professionals to identify and manage the long-term morbidity and mortality associated with these chronic conditions.

Epigenetic Factors as Etiological Agents, Diagnostic Markers, and Therapeutic Targets for Luminal Breast Cancer

Luminal breast cancer, an etiologically heterogeneous disease, is characterized by high steroid hormone receptor activity and aberrant gene expression profiles. Endocrine therapy and chemotherapy are promising therapeutic approaches to mitigate breast cancer proliferation and recurrence. However, the treatment of therapy-resistant breast cancer is a major challenge. Recent studies on breast cancer etiology have revealed the critical roles of epigenetic factors in luminal breast cancer tumorigenesis and drug resistance. Tumorigenic epigenetic factor-induced aberrant chromatin dynamics dysregulate the onset of gene expression and consequently promote tumorigenesis and metastasis. Epigenetic dysregulation, a type of somatic mutation, is a high-risk factor for breast cancer progression and therapy resistance. Therefore, epigenetic modulators alone or in combination with other therapies are potential therapeutic agents for breast cancer. Several clinical trials have analyzed the therapeutic efficacy of potential epi-drugs for breast cancer and reported beneficial clinical outcomes, including inhibition of tumor cell adhesion and invasiveness and mitigation of endocrine therapy resistance. This review focuses on recent findings on the mechanisms of epigenetic factors in the progression of luminal breast cancer. Additionally, recent findings on the potential of epigenetic factors as diagnostic biomarkers and therapeutic targets for breast cancer are discussed.

Design and synthesis of marine sesterterpene analogues as novel estrogen receptor α degraders for breast cancer treatment

Targeted protein degradation using small molecules is an intriguing strategy for drug development. The marine sesterterpene compound MHO7 had been reported to be a potential ERα degradation agent. In order to further improve its biological activity, two series of novel MHO7 derivatives with long side chains were designed and identified as novel selective estrogen receptor down-regulators (SERDs). The growth inhibition activity of the novel SERD compounds were significantly affected by the type and length of the side chain. Most of the derivatives were significantly more potent than MHO7 against both drug-sensitive and drug-resistant breast cancer cells. Among them, compound 16a, with IC₅₀ values of 0.41 μM against MCF-7 cell lines and 9.6-fold stronger than MHO7, was the most potential molecule. A whole-genome transcriptomic analysis of MCF-7 cells revealed that the mechanism of 16a against MCF-7 cell was similar with that of MHO7. The estrogen signaling pathway was the most affected among the disturbed genes, but the ERα degradation activity of 16a was observed higher than that of MHO7. Other effects of 16a were confirmed similar with MHO7, which means that the basic mechanisms of the derivatives are the same with the ophiobolin backbone, i.e. the degradation of ERα is mediated via proteasome-mediated process, the induction of apoptosis and the cell cycle arrest at the G1 phase. Meanwhile, a decrease of mitochondrial membrane potential and an increase of cellular ROS were also detected. Based on these results, as a novel modified ophiobolin derived compound, 16a may warrant further exploitation as a promising SERD candidate agent for the treatment of breast cancer.

[Early manifestation and progressive multicomponent current of McCune-Albright-Braitsev syndrome in a girl 9 years old: a clinical case and literature review]

McCune-Albright-Braitsev Syndrome (MAB syndrome) is a very rare multisystem disease manifested by fibrous bone dysplasia, coffee-and-milk colored spots, hyperfunction of various endocrine glands and a number of pathologies of other body systems. We present a description of a clinical case of a severe progressive course of MAB Syndrome in a nine-year-old girl. With this diagnosis, the girl is observation of the girl began when she was 2.5 years old, when spots of coffee-and-milk, polyosseous fibrous dysplasia, peripheral premature sexual development against a backdrop of estrogen--secreting ovarian cysts, multinodular goiter were detected. In the process of dynamic observation, it was noted that the child's active growth stopped against a backdrop of deformities of the skeletal system with multiple repeated fractures of the extremities; progression of skull deformity with stenosis of the optic nerve canals and deterioration of visual acuity; development of STH hypersecretion, hypophosphatemic rickets, tachycardia. Appropriate suppressive / replacement therapy was prescribed for each of the endocrine dysfunctions. The article presents algorithms for examining a girl in dynamics, criteria for choosing a component-wise management tactics and a discussion of the features of the course of all manifestations of the Syndrome.

Endometrial Surveillance in Tamoxifen and Letrozole Treated Breast Cancer Patients

Background: Our study aimed to assess the risk of endometrial pathologies after tamoxifen and aromatase inhibitors (AIs) adjuvant treatment for female breast cancer patients treated at Sultan Qaboos University Hospital in Oman.

Materials and Methods: A total of 457 patients diagnosed with estrogen positive breast cancer between January 2011 and December 2018 were screened. Two hundred and four patients met the inclusion criteria, and their detailed clinicopathological and endometrial surveillance data were collected from their electronic health records.

Results: All patients underwent endometrial assessment during tamoxifen or letrozole therapy. The mean diagnostic age of breast cancer patients is 43.6 years, ranging from 27-84 years. Eighty-three percent of those patients are premenopausal, and 17% are postmenopausal. The mean tamoxifen use duration was 33 months. The majority of patients, 123 (60.3%), have had tamoxifen for three years or less, 47 (23.1%) for 3-5 years, and only 22 (10.8%) were on tamoxifen for more than five years. Increased endometrial thickness was reported in 8% of the premenopausal and 14% of the postmenopausal group. Other endometrial pathologies that were detected are inactive endometrium three (1.47%), atrophic endometrium three (1.47%), serous carcinoma one (0.50%), endometrial cancer two (0.98%), and chronic endometritis one (0.50%), which were not significantly associated with tamoxifen or letrozole therapy duration. Two patients have developed endometrial cancer, and both are postmenopausal and > 60 years old.

Conclusions: Tamoxifen and letrozole did not increase the risk of endometrial cancer in premenopausal patients. Breast Cancer (BC) patients on tamoxifen or letrozole might need a pre-treatment endometrial evaluation and explanation of alarming symptoms to guide further endometrial surveillance.

Water extract of Er-xian decoction selectively exerts estrogenic activities and interacts with SERMs in estrogen-sensitive tissues

ETHNOPHARMACOLOGICAL RELEVANCE

The increasing use of "kidney"-nourishing Traditional Chinese Medicine (TCM) like Er-xian decoction (EXD) for management of menopausal symptoms and osteoporosis has aroused concerns about their safety, and whether they interact with prescription drugs as both of them act via estrogen receptors (ERs) and regulate serum estradiol.

AIM OF THE STUDY

The present study aimed to evaluate whether EXD selectively exerted estrogenic activities and interacted with Selective Estrogen Receptor Modulators (SERMs).

MATERIALS AND METHODS

In vivo, mature ovariectomized (OVX) rats were administrated with EXD or combined treatment of EXD and SERMs for 12 weeks. The tissue-selective effect of EXD and its interaction of SERMs were studied in four estrogen sensitive tissues, bone, brain, breast and uterus. In vitro, the interaction of extracts of EXD-treated serum and SERMs in four ER-positive cell lines.

RESULTS

In OVX rats, EXD selectively alleviated estrogen deficiency-induced changes in the bone and brain without inducing any estrogenic effects in the breast or uterus. Two-way ANOVA indicated the presence of interactions between EXD and SERMs in OVX rats but EXD did not significantly alter the tissue responses to SERMs in the bone, breast or brain. Indeed, the combined use of EXD and SERMs appeared to suppress the estrogenic effect of raloxifene and tamoxifen in the uterus. Extract of EXD-treated serum directly stimulated cell proliferation or differentiation in human osteosarcoma MG-63, neuroblastoma SHSY5Y, breast cancer MCF-7, and endometrial Ishikawa cells. Two-way ANOVA revealed that EXD-treated serum interacted with SERMs at various concentrations and altered the effects of tamoxifen in MG-63 and MCF-7 cells.

CONCLUSIONS

EXD exerted estrogenic effects in a tissue-selective manner and interacted with SERMs. Combined treatment of EXD and SERMs did not hamper the beneficial effects of SERMs on the bone or brain but appeared to moderate the estrogenic effect of SERMs in the uterus.

FLTX2: A Novel Tamoxifen Derivative Endowed with Antiestrogenic, Fluorescent, and Photosensitizer Properties

Tamoxifen is the most widely used selective modulator of estrogen receptors (SERM) and the first strategy as coadjuvant therapy for the treatment of estrogen-receptor (ER) positive breast cancer worldwide. In spite of such success, tamoxifen is not devoid of undesirable effects, the most life-threatening reported so far affecting uterine tissues. Indeed, tamoxifen treatment is discouraged in women under risk of uterine cancers. Recent molecular design efforts have endeavoured the development of tamoxifen derivatives with antiestrogen properties but lacking agonistic uterine tropism. One of this is FLTX2, formed by the covalent binding of tamoxifen as ER binding core, 7-nitrobenzofurazan (NBD) as the florescent dye, and Rose Bengal (RB) as source for reactive oxygen species. Our analyses demonstrate (1) FLTX2 is endowed with similar antiestrogen potency as tamoxifen and its predecessor FLTX1, (2) shows a strong absorption in the blue spectral range, associated to the NBD moiety, which efficiently transfers the excitation energy to RB through intramolecular FRET mechanism, (3) generates superoxide anions in a concentration- and irradiation time-dependent process, and (4) Induces concentration- and time-dependent MCF7 apoptotic cell death. These properties make FLTX2 a very promising candidate to lead a novel generation of SERMs with the endogenous capacity to promote breast tumour cell death in situ by photosensitization.

Complete remission of advanced low-grade endometrial stromal sarcoma after aromatase inhibitor therapy: a case report

Background

Low-grade endometrial stromal sarcoma is a rare neoplastic growth in the uterine cavity, representing less than 1% of uterine tumors. Such tumors usually affect premenopausal and perimenopausal women, with a mean age of 46 years. Treatment generally starts with surgical resection of the tumor, followed by chemotherapy, radiotherapy, or hormonal therapy.

Case presentation

In the current report, we again present a case of low-grade endometrial stromal sarcoma in a 51-year-old Mediterranean woman presenting with abdominopelvic pain. Computed tomography scan revealed a primary uterine tumor measuring 17 × 9 × 9 cm metastasizing to the lungs, bladder, and ureteral orifice, along with lymphovascular involvement. The patient underwent total abdominal hysterectomy, omentectomy, and lymph node dissection. Estrogen deprivation was accomplished by bilateral salpingo-oophorectomy. Lifelong hormonal therapy consisting of letrozole 2.5 mg per day was prescribed, which demonstrated remarkable efficacy, resulting in a partial remission of lung metastasis within 8 months after surgery. Full remission was observed after 18 months of hormonal therapy, with no recurrence. Another scan was performed after 2.5 years, revealing complete remission with no recurrence.

Conclusion

We again report a case of complete remission of low-grade endometrial stromal sarcoma after surgical removal of the tumor along with first-line hormonal therapy without the use of chemotherapy or radiotherapy, emphasizing the role of hormonal therapy in the treatment of such tumors.

Tumor Signature Analysis Implicates Hereditary Cancer Genes in Endometrial Cancer Development

Risk of endometrial cancer (EC) is increased ~2-fold for women with a family history of cancer, partly due to inherited pathogenic variants in mismatch repair (MMR) genes. We explored the role of additional genes as explanation for familial EC presentation by investigating germline and EC tumor sequence data from The Cancer Genome Atlas (n = 539; 308 European ancestry), and germline data from 33 suspected familial European ancestry EC patients demonstrating immunohistochemistry-detected tumor MMR proficiency. Germline variants in MMR and 26 other known/candidate EC risk genes were annotated for pathogenicity in the two EC datasets, and also for European ancestry individuals from gnomAD as a population reference set (n = 59,095). Ancestry-matched case-control comparisons of germline variant frequency and/or sequence data from suspected familial EC cases highlighted ATM, PALB2, RAD51C, MUTYH and NBN as candidates for large-scale risk association studies. Tumor mutational signature analysis identified a microsatellite-high signature for all cases with a germline pathogenic MMR gene variant. Signature analysis also indicated that germline loss-of-function variants in homologous recombination (BRCA1, PALB2, RAD51C) or base excision (NTHL1, MUTYH) repair genes can contribute to EC development in some individuals with germline variants in these genes. These findings have implications for expanded therapeutic options for EC cases.

Targeting the IL-6/STAT3 Signalling Cascade to Reverse Tamoxifen Resistance in Estrogen Receptor Positive Breast Cancer

Simple Summary

This study identifies the molecular mechanisms through which BQ323636.1 can enhance IL-6 and IL-6R expression, which leads to the activation of STAT3 and the development of tamoxifen resistance in ER+ breast cancer. We demonstrated a statistically significant association of IL-6R with tamoxifen resistance; patients with high IL-6R expression had poorer survival outcome. In vitro and in vivo studies confirmed that targeting IL-6R with Tocilizumab reduced tamoxifen resistance, providing the basis for potential use for disease management

Abstract

Breast cancer is the most common female cancer. About 70% of breast cancer patients are estrogen receptor α (ERα) positive (ER+) with tamoxifen being the most commonly used anti-endocrine therapy. However, up to 50% of patients who receive tamoxifen suffer recurrence. We previously identified BQ323636.1 (BQ), a novel splice variant of NCOR2, can robustly predict tamoxifen resistance in ER+ primary breast cancer. Here we show that BQ can enhance IL-6/STAT3 signalling. We demonstrated that through interfering with NCOR2 suppressive activity, BQ favours the binding of ER to IL-6 promoter and the binding of NF-ĸB to IL-6 receptor (IL-6R) promoter, leading to the up-regulation of both IL-6 and IL-6R and thus the activation of STAT3. Knockdown of IL-6R could compromise tamoxifen resistance mediated by BQ. Furthermore, Tocilizumab (TCZ), an antibody that binds to IL-6R, could effectively reverse tamoxifen resistance both in vitro and in vivo. Analysis of clinical breast cancer samples confirmed that IL-6R expression was significantly associated with BQ expression and tamoxifen resistance in primary breast cancer, with high IL-6R expression correlating with poorer survival. Multivariate Cox-regression analysis confirmed that high IL-6R expression remained significantly associated with poor overall as well as disease-specific survival in ER+ breast cancer.

Proteolytic Targeting Chimeras with Specificity for Plasma Membrane and Intracellular Estrogen Receptors

Decisions regarding the assignment of hormonal therapy for breast cancer are based solely upon the presence of nuclear estrogen receptors (ERs) in biopsied tumor tissue. This is despite the fact that the G-protein-coupled estrogen receptor (GPER) is linked to advanced breast cancer and is required for breast cancer stem cell survival, an observation that suggests that effective endocrine therapy should also target this receptor. Here, two ER/GPER-targeting proteolytic chimeras (UI-EP001 and UI-EP002) are described that effectively degrade ERα, ERβ, and GPER. These chimeras form high-affinity interactions with GPER and ER with binding dissociation constants of ∼30 nM and 10-20 nM, respectively. Plasma membrane and intracellular GPER and nuclear ER were degraded by UI-EP001 and UI-EP002, but not by a partial proteolytic targeting chimera (PROTAC) lacking its estrogen-targeting domain. Pretreatment of cells with the proteasomal inhibitor, MG132, blocked UI-EP001 and UI-EP002 proteolysis, while the lysosomotrophic inhibitor, chloroquine, had no effect. The off-target activity was not observed against recombinant β1-adrenergic receptor or CXCR4. Target specificity was further demonstrated in human MCF-7 cells where both drugs effectively degraded ERα, ERβ, and GPER, sparing the progesterone receptor (PR). UI-EP001 and UI-EP002 induced cytotoxicity and G2/M cell cycle arrest in MCF-7 breast cancer and human SKBR3 (ERα-ERβ-GPER+) breast cancer cells but not human MDA-MB-231 breast cancer cells that do not express functional GPER/ER. These results suggest that it is possible to develop a receptor-based strategy of antiestrogen treatment for breast cancer that targets both plasma membrane and intracellular estrogen receptors.

Enhancing endocrine therapy activity via fasting cycles: biological rationale and clinical feasibility

We found that periodic fasting increases the anti-cancer activity of endocrine agents used to treat hormone receptor-positive breast cancer and delays acquired resistance to them by reducing blood leptin, insulin and insulin-like growth factor 1 (IGF1). Our work supports further clinical studies of fasting as an adjuvant to endocrine agents in breast cancer patients.

Atypical vessels in hysteroscopy: Usefulness in prediction of malignant diseases in patients treated with tamoxifen

AIM

Tamoxifen (TAM) is widely used in adjuvant endocrine therapy for invasive breast cancer as a selective estrogen modulator, but this treatment has a risk of developing endometrial malignancy. However, hysteroscopic findings during or after TAM treatment are unclear. The aim of this study is to examine the association between hysteroscopic patterns and malignant histological findings during or after treatment with TAM.

METHODS

The subjects were patients who received TAM after surgery for breast cancer and underwent hysteroscopy at our institution from January 2016 to December 2019. Clinicopathological factors and hysteroscopic findings were collected from medical records and investigated retrospectively. Histologically, atypical endometrial hyperplasia, endometrial cancer, and carcinosarcoma were classified as malignant diseases.

RESULTS

A total of 26 patients were eligible for the study. Hysteroscopic findings included an irregular surface of the endometrium (n = 3, 11.5%), atypical vessels (n = 10, 38.5%), papillary structure (n = 3, 11.5%), and polypoid structure (n = 18, 69.2%). Histological examination revealed malignancy in six patients (23.0%). The percentage of atypical vessels in patients with malignancies was significantly higher than that in patients with a normal endometrium or benign lesion (100% vs. 20%, p = 0.0009). The sensitivity and specificity of atypical vessels in hysteroscopy for diagnosis of malignant diseases were 100% and 80%, respectively.

CONCLUSIONS

Hysteroscopic findings of atypical vessels may be useful for prediction of malignant diseases in patients treated with TAM.

The Central Roles of Noncoding RNA in Estrogen-Dependent Female Reproductive System Tumors

The pathogenesis of ovarian and endometrial cancers is closely associated with estrogen-related pathways. These estrogen-dependent tumors seriously threaten the health and quality of life in women. Noncoding RNAs (ncRNAs) are defined as RNAs that do not encode proteins, including microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), both of which have been reported in estrogen-dependent female reproductive system tumors. This review systematically summarizes the role of ncRNAs in estrogen-dependent tumors and common patterns of regulatory mechanisms to explore their future research directions in tumor diagnosis, treatment, and prognosis. This may provide new ideas for the potential application of ncRNAs in estrogen-dependent female reproductive system tumors.

Molecular Signaling Pathways and Essential Metabolic Elements in Bone Remodeling: An Implication of Therapeutic Targets for Bone Diseases

Bone is one of the dynamic tissues in the human body that undergoes continuous remodelling through subsequent actions of bone cells, osteoclasts, and osteoblasts. Several signal transduction pathways are involved in the transition of mesenchymal stem cells into osteoblasts. These primarily include Runx2, ATF4, Wnt signaling and sympathetic signalling. The differentiation of osteoclasts is controlled by M-CSF, RANKL, and costimulatory signalling. It is well known that bone remodelling is regulated through receptor activator of nuclear factor-kappa B ligand followed by binding to RANK, which eventually induces the differentiation of osteoclasts. The resorbing osteoclasts secrete TRAP, cathepsin K, MMP-9 and gelatinase to digest the proteinaceous matrix of type I collagen and form a saucer-shaped lacuna along with resorption tunnels in the trabecular bone. Osteoblasts secrete a soluble decoy receptor, osteoprotegerin that prevents the binding of RANK/RANKL and thus moderating osteoclastogenesis. Moreover, bone homeostasis is also regulated by several growth factors like, cytokines, calciotropic hormones, parathyroid hormone and sex steroids. The current review presents a correlation of the probable molecular targets underlying the regulation of bone mass and the role of essential metabolic elements in bone remodelling. Targeting these signaling pathways may help to design newer therapies for treating bone diseases.

Genomics and splicing events of type II endometrial cancers in the black population: racial disparity, socioeconomic and geographical differences

Endometrial cancer, also known as uterine cancer, is the most common gynaecological malignancy with burgeoning incidence and mortality rates globally. Racial disparity, socioeconomic and geographical differences are important determinants of endometrial cancer incidence and mortality. Endometrial cancer is mainly categorised as type I and type II. Although less prevalent, type II is the most aggressive form of the disease and typically diagnosed at a late stage, contributing to higher mortality. Black women are at higher risk of developing aggressive, type II disease. Type I tumours are related to higher levels of circulating estrogen with lower-grade tumours that have a good prognosis and frequently related to PTEN mutations. In comparison, type II tumours are estrogen-independent, typically have poor prognosis and associated with the p53, HER2, PPP2R1A, FBXW7 and PIK3R1 mutations. The risk of developing type II malignancy is higher in women with Lynch syndrome as a result of mutations in the MMR gene family. Genetic modifications contribute to aberrant alternative splicing events that are related to tumour development, progression and resistance to therapy. Alternative splicing events are rapidly emerging as potential biomarkers and therapeutic targets. Type II endometrial cancer lacks targeted therapy and biomarkers for novel therapeutic strategies. Recent advances have illustrated a number of molecular targets that are currently explored for the treatment of advanced, late-stage endometrial cancer. The aim of this review is to outline 1) the epidemiology of type II endometrial cancer in black women, 2) discuss the correlated risk factors that contribute to the development of type II endometrial cancer and 3) the associated molecular mechanisms and genetic factors underlying the disease, and 4) aberrant splicing events and biomarkers with therapeutic potential as novel drug targets.

Tamoxifen and Endometrial Cancer: A Janus-Headed Drug

Simple Summary

Tamoxifen, an antiestrogen, is a potent drug to treat and prevent hormone dependent breast cancer. As it has low toxicity and is widely available, tamoxifen has become one of the most frequently prescribed anticancer drugs worldwide. A major side effect of tamoxifen is to increase the risk of uterine corpus cancer (endometrial cancer). This happens after long-term (>2 years) application, especially in postmenopausal women with preexisting pathologies in the uterus. On the other hand, tamoxifen is an efficacious treatment for certain forms of advanced endometrial cancer, thus making it a Janus-headed drug that can support the development of endometrial cancer on one hand and be used as a remedy for this disease on the other. This article reviews the clinical data on these controversial effects of tamoxifen and the possible explanations.

Abstract

Tamoxifen is a selective estrogen receptor modulator used for the treatment and prevention of estrogen receptor (ER)—positive breast cancer. However, tamoxifen increases the risk of endometrial cancer (EC) by about 2–7 fold, and more aggressive types of EC with poor prognoses are observed in tamoxifen users. On the other hand, tamoxifen is an efficacious treatment for advanced or recurrent EC with low toxicity. The differential agonistic or antagonistic effects of tamoxifen on ERα are explained by the tissue-specific expression profiles of co-activators and co-repressors of the receptor. The estrogen-agonistic effect of tamoxifen in endometrial cancers can also be explained by the expression of G-protein coupled estrogen receptor 1 (GPER-1), a membrane-bound estrogen receptor for which tamoxifen and other “antiestrogens” are pure agonists.

Enhanced in vivo targeting of estrogen receptor alpha signaling in murine mammary adenocarcinoma by nilotinib/rosuvastatin novel combination

The development of resistance to endocrine therapy of estrogen receptor alpha (ERα)-positive breast cancer is inevitable, necessitating the introduction of alternative treatment strategies. Therefore, the current study was carried out to investigate the in vivo efficacy and tolerability of nilotinib/rosuvastatin novel combination against ERα-positive breast carcinoma. Results showed that treatment of tumor-bearing mice with nilotinib/rosuvastatin exerted a significant antitumor activity. Mechanistically, the combination treatment efficiently inhibited the in vivo ERα protein expression, whereas ERα mRNA levels were unaffected suggesting a posttranslational regulation. In addition, the combination treatment markedly downregulated the expression of two ERα downstream target genes: C3 and pS2 confirming the inhibition of ERα signaling in vivo. Further, nilotinib/rosuvastatin combination strongly induced apoptosis evidenced by a marked caspase-3 cleavage and downregulation of tumor nitric oxide levels. Moreover, histopathology showed significant declines in mitotic figures and tumor giant cells implying the in vivo capability of the combination treatment to interfere with cancer cell proliferation and persistence. Of note, the combination treatment abrogated nilotinib-induced hypercholesterolemia and did not adversely affect the liver function or body weight. Overall, the present study provided evidences that warrant further assessment of nilotinib/rosuvastatin combination as an alternative therapeutic modality for ERα-positive breast cancer.

Fasting-mimicking diet and hormone therapy induce breast cancer regression

Approximately 75% of all breast cancers express the oestrogen and/or progesterone receptors. Endocrine therapy is usually effective in these hormone-receptor-positive tumours, but primary and acquired resistance limits its long-term benefit^1,2. Here we show that in mouse models of hormone-receptor-positive breast cancer, periodic fasting or a fasting-mimicking diet^3-5 enhances the activity of the endocrine therapeutics tamoxifen and fulvestrant by lowering circulating IGF1, insulin and leptin and by inhibiting AKT-mTOR signalling via upregulation of EGR1 and PTEN. When fulvestrant is combined with palbociclib (a cyclin-dependent kinase 4/6 inhibitor), adding periodic cycles of a fasting-mimicking diet promotes long-lasting tumour regression and reverts acquired resistance to drug treatment. Moreover, both fasting and a fasting-mimicking diet prevent tamoxifen-induced endometrial hyperplasia. In patients with hormone-receptor-positive breast cancer receiving oestrogen therapy, cycles of a fasting-mimicking diet cause metabolic changes analogous to those observed in mice, including reduced levels of insulin, leptin and IGF1, with the last two remaining low for extended periods. In mice, these long-lasting effects are associated with long-term anti-cancer activity. These results support further clinical studies of a fasting-mimicking diet as an adjuvant to oestrogen therapy in hormone-receptor-positive breast cancer.

Endocrine Risk Factors of Endometrial Cancer: Polycystic Ovary Syndrome, Oral Contraceptives, Infertility, Tamoxifen

Endometrial cancer is the most common gynecologic cancer and is predominantly endocrine-related. The role of unopposed estrogen in the development of endometrial cancer has been investigated in numerous studies. Different reproductive factors such as younger age at menarche, late age at menopause, infertility, nulliparity, age of birth of the first child, and long-term use of unopposed estrogens during hormone replacement therapy have been associated with an increased risk of endometrial cancer. In contrast, there is a growing body of evidence for a protective role of oral contraceptives. Most of the published data on the association between infertility and polycystic ovary syndrome are inconclusive, whereas the effect of tamoxifen on the risk of endometrial cancer has been well established. With this review, we aim to summarize the evidence on the association between infertility, polycystic ovary syndrome, oral contraceptives, and tamoxifen and the development of endometrial cancer.

Reprogramming of Mesothelial-Mesenchymal Transition in Chronic Peritoneal Diseases by Estrogen Receptor Modulation and TGF-β1 Inhibition

In chronic peritoneal diseases, mesothelial-mesenchymal transition is determined by cues from the extracellular environment rather than just the cellular genome. The transformation of peritoneal mesothelial cells and other host cells into myofibroblasts is mediated by cell membrane receptors, Transforming Growth Factor β1 (TGF-β1), Src and Hypoxia-inducible factor (HIF). This article provides a narrative review of the reprogramming of mesothelial mesenchymal transition in chronic peritoneal diseases, drawing on the similarities in pathophysiology between encapsulating peritoneal sclerosis and peritoneal metastasis, with a particular focus on TGF-β1 signaling and estrogen receptor modulators. Estrogen receptors act at the cell membrane/cytosol as tyrosine kinases that can phosphorylate Src, in a similar way to other receptor tyrosine kinases; or can activate the estrogen response element via nuclear translocation. Tamoxifen can modulate estrogen membrane receptors, and has been shown to be a potent inhibitor of mesothelial-mesenchymal transition (MMT), peritoneal mesothelial cell migration, stromal fibrosis, and neoangiogenesis in the treatment of encapsulating peritoneal sclerosis, with a known side effect and safety profile. The ability of tamoxifen to inhibit the transduction pathways of TGF-β1 and HIF and achieve a quiescent peritoneal stroma makes it a potential candidate for use in cancer treatments. This is relevant to tumors that spread to the peritoneum, particularly those with mesenchymal phenotypes, such as colorectal CMS4 and MSS/EMT gastric cancers, and pancreatic cancer with its desmoplastic stroma. Morphological changes observed during mesothelial mesenchymal transition can be treated with estrogen receptor modulation and TGF-β1 inhibition, which may enable the regression of encapsulating peritoneal sclerosis and peritoneal metastasis.

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) method development for screening of potential tamoxifen-drug/herb interaction via in vitro cytochrome P450 inhibition assay

Screening for potential drug-drug interaction (DDI) or herb-drug interaction (HDI) using in vitro cytochrome P450 inhibition (IVCI) assays requires robust analytical methods with high sensitivity and reproducibility. Utilization of liquid chromatography-mass spectrometry (LC-MS) for analyte quantification is often hampered by the presence of non-volatile IVCI sample buffer constituents that often results in ion suppression. In this study, to enable screening of drug interactions involving tamoxifen (TAM) metabolism using IVCI-LC-MS/MS, a liquid-liquid extraction (LLE) method was developed and optimized for sample clean-up. Utilization of chloroform as extraction solvent and adjustment of sample pH to 11 was found to result in satisfactory recovery (>70%) and low ion suppression (<19%). A LC-MS/MS method was subsequently developed and validated for simultaneous quantification of major TAM metabolites, such as N-desmethyltamoxifen (NDT), endoxifen (EDF) and 4-hydroxytamoxifen (HTF) to enable IVCI sample analysis. Satisfactory separation of E-/Z-isomers of endoxifen with peak resolution (Rs) of 1.9 was achieved. Accuracy and precision of the method was verified within the linear range of 0-50 ng/mL for NDT, 0-25 ng/mL for HTF and 0-25 ng/mL for EDF (E/Z isomers). Inhibitory potency (IC50, Ki and mode of inhibition) of known CYP inhibitors and Strobilanthes crispus extract was then evaluated using the validated method. In summary, the results demonstrated applicability of the developed LLE and validated LC-MS/MS method for in vitro screening of DDI and HDI involving TAM metabolism.

SWATH-MS Analysis of FFPE Tissues Identifies Stathmin as a Potential Marker of Endometrial Cancer in Patients Exposed to Tamoxifen

A specific form of endometrial cancer (EC) can develop in breast cancer patients previously treated with tamoxifen (ET), an antagonist of estrogen receptor (ER) that inhibits proliferation of ER positive breast cancer. ET tumors have a different phenotype than endometrial tumors, which typically develop de novo without previous exposure to tamoxifen (EN). Here we aimed to identify specific protein markers that could serve as specific molecular targets in either phenotype. A set of total 45 formalin-fixed paraffin-embedded (FFPE) endometrial tumor tissues and adjacent myometrium tissue samples were analyzed using LC-MS/MS in SWATH-MS mode. We found that calcyphosin (CAPS) levels were elevated in EN tumors compared to ET tumors. The higher CAPS level in EC tissue invading to myometrium supports its relationship to EC aggressiveness. Further, stathmin (STMN1) levels were found significantly elevated in ET versus EN tumors and significantly associated with patient survival. This finding connects elevated levels of this cell cycle regulating, proliferation-associated protein with tamoxifen exposure. In summary, using SWATH-MS we show that CAPS and STMN1 should be recognized as clinicopathologically different EC markers of which STMN1 is specifically connected with a previous tamoxifen exposition.

Protein modification by thiolactone homocysteine chemistry: a multifunctionalized human serum albumin theranostic

As the most abundant protein with a variety of physiological functions, albumin has been used extensively for the delivery of therapeutic molecules. Thiolactone chemistry provides a powerful tool to prepare spin-labeled albumin-based multimodal imaging probes and therapeutic agents. We report the synthesis of a tamoxifen homocysteine thiolactone derivative and its use in thiol-'click' chemistry to prepare multi-functionalized serum albumin. The released sulfhydryl group of the homocysteine functional handle was labeled with a nitroxide reagent to prepare a spin-labeled albumin-tamoxifen conjugate confirmed by MALDI-TOF-MS, EPR spectroscopy, UV-vis and fluorescent emission spectra. This is the basis for a novel multimodal tamoxifen-albumin theranostic with a significant (dose-dependent) inhibitory effect on the proliferation of malignant cells. The response of human glioblastoma multiforme T98G cells and breast cancer MCF-7 cells to tamoxifen and its albumin conjugates was different in tumor cells with different expression level of ERα in our experiments. These results provide further impetus to develop a serum protein for delivery of tamoxifen to cancer cells.

Association Between Hormone-Modulating Breast Cancer Therapies and Incidence of Neurodegenerative Outcomes for Women With Breast Cancer

Importance

The association between exposure to hormone-modulating therapy (HMT) as breast cancer treatment and neurodegenerative disease (NDD) is unclear.

Objective

To determine whether HMT exposure is associated with the risk of NDD in women with breast cancer.

Design, Setting, and Participants

This retrospective cohort study used the Humana claims data set from January 1, 2007, to March 31, 2017. The Humana data set contains claims from private-payer and Medicare insurance data sets from across the United States with a population primarily residing in the Southeast. Patient claims records were surveyed for a diagnosis of NDD starting 1 year after breast cancer diagnosis for the duration of enrollment in the claims database. Participants were 57 843 women aged 45 years or older with a diagnosis of breast cancer. Patients were required to be actively enrolled in Humana claims records for 6 months prior to and at least 3 years after the diagnosis of breast cancer. The analyses were conducted between January 1 and 15, 2020.

Exposure

Hormone-modulating therapy (selective estrogen receptor modulators, estrogen receptor antagonists, and aromatase inhibitors).

Main Outcomes and Measures

Patients receiving HMT for breast cancer treatment were identified. Survival analysis was used to determine the association between HMT exposure and diagnosis of NDD. A propensity score approach was used to minimize measured and unmeasured selection bias.

Results

Of the 326 485 women with breast cancer in the Humana data set between 2007 and 2017, 57 843 met the study criteria. Of these, 18 126 (31.3%; mean [SD] age, 76.2 [7.0] years) received HMT, whereas 39 717 (68.7%; mean [SD] age, 76.8 [7.0] years) did not receive HMT. Mean (SD) follow-up was 5.5 (1.8) years. In the propensity score-matched population, exposure to HMT was associated with a decrease in the number of women who received a diagnosis of NDD (2229 of 17 878 [12.5%] vs 2559 of 17 878 [14.3%]; relative risk, 0.89; 95% CI, 0.84-0.93; P < .001), Alzheimer disease (877 of 17 878 [4.9%] vs 1068 of 17 878 [6.0%]; relative risk, 0.82; 95% CI, 0.75-0.90; P < .001), and dementia (1862 of 17 878 [10.4%] vs 2116 of 17 878 [11.8%]; relative risk, 0.88; 95% CI, 0.83-0.93; P < .001). The number needed to treat was 62.51 for all NDDs, 93.61 for Alzheimer disease, and 69.56 for dementia.

Conclusions and Relevance

Among patients with breast cancer, tamoxifen and steroidal aromatase inhibitors were associated with a decrease in the number who received a diagnosis of NDD, specifically Alzheimer disease and dementia.

Drug-Related Carcinogenesis: Risk Factors and Approaches for Its Prevention

The review summarizes the data on the role of metabolic and repair systems in the mechanisms of therapy-related carcinogenesis and the effect of their polymorphism on the cancer development risk. The carcinogenic activity of different types of drugs, from the anticancer agents to analgesics, antipyretics, immunomodulators, hormones, natural remedies, and non-cancer drugs, is described. Possible approaches for the prevention of drug-related cancer induction at the initiation and promotion stages are discussed.

Application and biomolecular study of functionalized folic acid-dendrimer nanoparticles in drug delivery

We determined the loading efficacy of folic acid - PAMAM - G3 and folic acid - PAMAM - G4 nanoparticles with doxorubicin (Dox), tamoxifen (Tam) and tetracycline (Tet) in aqueous solution at pH 7.2. Thermodynamic parameters ΔH⁰ -16 to -4 (kJ mol^-1), ΔS⁰ 31 to -0.3 (J mol^-1K^-1) and ΔG⁰ -14 to -11 (kJ mol^-1) showed drug folic acid-PAMAM bindings are via ionic, H-bonding and van der Waals interactions. As acid - PAMAM size increased the stability and loading efficacy of drug-polymer conjugates were increased. The order of stability for drug-nanoparticles was doxorubicin > tetracycline > tamoxifen. TEM analysis showed major polymer morphological changes, upon drug encapsulation. Folic acid-PAMAM conjugates are effective drug delivery tools in vitro. Communicated by Ramaswamy H. Sarma.

Red clover and lifestyle changes to contrast menopausal symptoms in premenopausal patients with hormone-sensitive breast cancer receiving tamoxifen

PURPOSE

To determine whether a red clover preparation plus dietary intervention administered to premenopausal women with breast cancer (BC), improves menopausal symptoms due to anti-oestrogen treatment, and hence promotes compliance with tamoxifen, prevents weight gain and is safe.

METHODS

Surgically-treated premenopausal women with oestrogen receptor (ER) positive disease taking tamoxifen were recruited to a prospective double-blind randomized trial (NCT03844685). The red clover group (N = 42) received one oral tablet/day (Promensil^® Forte) containing 80 mg red clover extract for 24 months. The placebo group (N = 39) received one oral tablet/day without active ingredient. All women were encouraged to follow a Mediterranean-type diet and keep active. Outcomes were Menopausal Rating Score (MRS), body mass index (BMI), waist and hip girth, insulin resistance, and levels of cholesterol, triglycerides, and sex hormones. As safety indicators, endometrial thickness, breast density, and effects of patient serum on ER-positive BC cell lines were investigated.

RESULTS

MRS reduced significantly (p < 0.0001) with no between-group difference (p = 0.69). The red clover group had significantly greater reductions in BMI and waist circumference (p < 0.0001 both cases). HDL cholesterol increased significantly in both groups (p = 0.01). Hormone levels and insulin resistance changed little. Endometrial thickness remained constant (p = 0.93). Breast density decreased significantly in both groups (p < 0.0001). Proliferation and oestrogen-regulated gene expression didn't differ in cell lines treated with serum from each group.

CONCLUSIONS

This is the first trial to assess red clover in BC patients on tamoxifen. The preparation proved safe clinically and in vitro, and was associated with reduced BMI and waist circumference, but the diet-lifestyle intervention probably improved the menopausal symptoms.

1,2,4-Oxadiazole-5-ones as analogues of tamoxifen: synthesis and biological evaluation

A series of 2,3,4-triaryl-substituted 1,2,4-oxadiazole-5-ones have been prepared as fixed-ring analogues of tamoxifen (TAM), a drug inhibitor of Estradiol Receptor (ER) used in breast cancer therapy, by an efficient synthetic protocol based on a 1,3-dipolar cycloaddition of nitrones to isocyanates. Some of the newly synthesized compounds (14d-f, 14h and 14k) show a significant cytotoxic effect in a human breast cancer cell line (MCF-7) possessing IC50 values between 15.63 and 31.82 μM. In addition, compounds 14d-f, 14h and 14k are able to increase the p53 expression levels, activating also the apoptotic pathway. Molecular modeling studies of novel compounds performed on the crystal structure of ER reveal the presence of strong hydrophobic interactions with the aromatic rings of the ligands similar to TAM. These data suggest that 1,2,4-oxadiazole-5-ones can be considered analogues of TAM, and that their anticancer activity might be partially due to ER inhibition.

Alginate based tamoxifen/metal dual core-folate decorated shell: Nanocomposite targeted therapy for breast cancer via ROS-driven NF-κB pathway modulation

Breast cancer endocrine resistance prevents unleashing full capabilities of Tamoxifen (TMX), besides TMX off-target side effects on healthy tissue. In this study, we engineered TMX nanocomposite via co-loading it on alginate-based silver nanoparticles and embedding within folic acid-polyethylene glycol surface conjugate. The coating process was done by w/o/w double emulsion method. To confirm the silver nanoparticles formation, UV spectroscopy, XRD and TEM analysis were carried out. TEM results confirmed the core-shell structure of folate targeted nanocomposite with approximate average diameter of 66 nm, the nanocomposite structures were characterized by FTIR, TGA and SEM. By comparing with the non-targeted formula, folate decorated formula had 12-folds lowered IC₅₀ value and 12.5-14-fold higher cancer cells toxic selectivity index. Also, after 4 h treatment, both fluorescence microscopic and flow cytometric analysis indicated higher intracellular accumulation of folic acid conjugated formula on MCF-7 cancer cells than the non-targeted one with 3.44-folds. The breast cancer cytotoxic effects of this metal-endocrine nanocomposite formula could be explained by the induction of reactive oxygen species (ROS), down regulation of survival oncogenic genes (BCL-2 and Survivin) and the accumulation of MCF-7 cells in G2/M phase. All these data confirm the efficiency and efficacy of the formulated nanocomposite as future treatment for breast cancer.

Cytotoxicity Of Chalcone Of Eugenia aquea Burm F. Leaves Against T47D Breast Cancer Cell Lines And Its Prediction As An Estrogen Receptor Antagonist Based On Pharmacophore-Molecular Dynamics Simulation

Background

The 2ʹ,4ʹ-dihydroxy-6-methoxy-3,5-3-dimethylchalcone (ChalcEA) isolated from Eugenia aquea Burm f. leaves has potential anticancer activity against human breast-adenocarcinoma cell lines (MCF-7) with an IC₅₀ value of 250 µM. However, its apoptotic activity on the T47D breast cancer cell lines which is involving caspase-3 has not been investigated.

Materials and methods

Therefore, this study aims to evaluate the cytotoxicity of ChalcEA on the T47D cell lines using the 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium (WST) method and to predict its possible antagonistic activity on the human estrogen receptor alpha (hERα) using pharmacophore and molecular dynamics (MD) methods. The in vitro test of 10 synthesized ChalcEA derivatives was also performed as an insight into the further development of its structure as an anticancer agent.

Results

It is shown that ChalcEA has an IC₅₀ of 142.58 ± 4.6 µM against the hERα-overexpressed T47D breast cancer cell lines, indicating its possible mechanism of anticancer activity as an antagonist of hERα. Pharmacophore study showed that ChalcEA shares similar features with the known hERα antagonist, 4-hydroxytamoxifen (4-OHT), which has hydrogen bond donor (HBD), hydrogen bond acceptor (HBA), ring aromaticity (RA), and hydrophobicity (Hy) features. Molecular docking showed that ChalcEA formed hydrogen bonds with Glu353 and Arg394, and hydrophobic interactions in a similar manner with 4-OHT. Moreover, MD simulations showed that ChalcEA destabilized the conformation of His524, a remarkable behavior of a known hERa antagonist, including 4-OHT. Furthermore, the 10 best chalcone derivatives resulted from pharmacophore- and docking-based screening, were tested against the T47D cell lines. None of the derivatives have better activity than ChalcEA. It is suggested that the functional groups at the B-ring of ChalcEA are interesting to be further optimized in the next studies.

Conclusion

ChalcEA might act as an antagonist toward hERα, thus warranting further investigation as a potential anticancer agent.

Endocrine and Targeted Therapy for Hormone-Receptor-Positive, HER2-Negative Advanced Breast Cancer: Insights to Sequencing Treatment and Overcoming Resistance Based on Clinical Trials

Background: Advanced hormone-receptor positive HER2 negative breast cancer is a common and a very heterogeneous disease. Hormone therapy is the main first line treatment of choice, given alone or in combination with other agents that have shown to improve patient outcomes, Nevertheless, treatment remains generally palliative rather than curative. Sequencing of such treatment remains challenging, especially with resurgence of variable resistance patterns. Multiple attempts have been made to overcome resistance and improve patient survival, yet resistance remains not very well understood and metastatic cancer remains a disease with dismal prognosis.

Methods: In this paper, we searched pubmed database as well as local and international meetings for all studies discussing advanced and metastatic hormone-receptor-positive, her2-negative breast cancer, hormonal treatment, resistance to hormonal treatment, mechanism of resistance, and means to overcome such resistance.

Conclusion: There does not exist an optimal treatment sequence for hormone-receptor-positive, her2-negative advanced breast cancer. However, after review of literature, a reasonable approach may be starting with tamoxifen, aromatase inhibitors, or fulvestrant in absence of visceral crisis, in addition to ensuring adequate ovarian function suppression in pre/peri-menopausal women. Aromatase inhibitors and fulvestrant seem to be superior. Resistance to such agents is increasing, mostly attributed to genetic and molecular changes. Multiple modalities are addressed to overcome such resistance including use of CKD4/6 inhibitors, mTOR inhibitors and PI3K inhibitors in addition to other agents under study, all with promising results. CDK4/6 inhibitors work best when used in frontline setting. Finally, treatment of breast cancer remains a growing field, and more studies are to be awaited.

Tamoxifen use as a malignancy risk factor in postmenopausal women with endometrial polyps

OBJECTIVE

We analyzed tamoxifen use as a malignancy risk factor in women with endometrial polyps.

METHODS

This retrospective study included 675 women who underwent hysteroscopic polypectomy in 2010 to 2015 at the University of Campinas. Women were divided into tamoxifen use (n = 169) and no tamoxifen use (n = 506) groups. The primary outcome was endometrial cancer prevalence. Dependent variables included age, parity, years since menopause, presence of abnormal uterine bleeding, endometrial pattern on hysteroscopy, and endometrial thickness.

RESULTS

There were seven cases of endometrial cancer in the tamoxifen use group (4.14%) and 41 in the no tamoxifen use group (8.1%; P = 0.083). On performing multivariate analysis, tamoxifen use was not a risk factor for endometrial cancer (prevalence ratio 0.51, 95% confidence interval [CI] 0.23-1.14, P = 0.101). The no tamoxifen use group had an increased prevalence of malignancy when women presented with abnormal uterine bleeding (prevalence ratio 3.9, 95% CI 2.08-7.29, P < 0.001), age >60 years (prevalence ratio 2.1, 95% CI 1.12-3.93, P = 0.021), or nulliparous status (prevalence ratio 3.13, 95% CI 1.55-6.35, P = 0.002). The tamoxifen use group had increased prevalence of malignancy when women were >60 years (prevalence ratio 7.85, 95% CI 1.05-58.87, P = 0.006) or nulliparous (prevalence ratio 8.36, 95% CI 2.32-30.11, P < 0.001).

CONCLUSION

Tamoxifen use was not related with a higher prevalence of endometrial cancer in women with endometrial polyps. Abnormal uterine bleeding, age > 60 years, and nulliparous status were associated with malignancy.