Selective Estrogen Receptor Modulators Research Articles

Enhanced oral bioavailability of levormeloxifene and raloxifene by nanoemulsion: simultaneous bioanalysis using liquid chromatography-tandem mass spectrometry.

Aim & objective: Levormeloxifene (L-ORM) and raloxifene (RAL) are selective estrogen receptor modulators used in the treatment of postmenopausal osteoporosis and breast cancer. Here, we developed and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous estimation of both drugs. Materials & methods: A quality-by-design (QbD) approach was used for the optimization of the nanoemulsion, and US FDA guidelines were followed for method validation. Results: Multiple reaction monitoring transitions were used for L-ORM (459.05→98.50), RAL (475.00→112.02) and internal standard (180.10→110.2). Analytes were resolved in a C18 column with 80:20 v/v% acetonitrile (ACN), 0.1% formic acid in triple-distilled water as a mobile phase. The developed method was linear over a concentration range of 1-600ng/ml. Pharmacokinetic results of free L-ORM-RAL and the L-ORM-RAL nanoemulsion showed Cmax of free L-ORM- 70.65±16.64, free RAL13.53±2.72, L-ORM nanoemulsion 65.07±14.0 and RAL-nanoemulsion 59.27±17.44ng/ml. Conclusion: Future findings will contribute to the treatment of postmenopausal osteoporosis and breast cancer using L-ORM and RAL.

Osteoporosis treatments for intervertebral disc degeneration and back pain: a perspective.

Low back pain derived from intervertebral disc (IVD) degeneration is a debilitating spinal condition that, despite its prevalence, does not have any intermediary guidelines for pharmacological treatment between palliative care and invasive surgery. The development of treatments for the IVD is complicated by the variety of resident cell types needed to maintain the regionally distinct structural properties of the IVD that permit the safe, complex motions of the spine. Osteoporosis of the spine increases the risk of vertebral bone fracture that can increase the incidence of back pain. Fortunately, there are a variety of pharmacological treatments for osteoporosis that target osteoblasts, osteoclasts and/or osteocytes to build bone and prevent vertebral fracture. Of particular note, clinical and preclinical studies suggest that commonly prescribed osteoporosis drugs like bisphosphonates, intermittent parathyroid hormone, anti-sclerostin antibody, selective estrogen receptor modulators and anti-receptor activator of nuclear factor-kappa B ligand inhibitor denosumab may also relieve back pain. Here, we cite clinical and preclinical studies and include unpublished data to support the argument that a subset of these therapeutics for osteoporosis may alleviate low back pain by also targeting the IVD.

The estrogen signaling pathway reprograms prostate cancer cell metabolism and supports proliferation and disease progression.

Just like the androgen receptor (AR), the estrogen receptor α (ERα) is expressed in the prostate and is thought to influence prostate cancer (PCa) biology. Yet the incomplete understanding of ERα functions in PCa hinders our ability to fully comprehend its clinical relevance and restricts the repurposing of estrogen-targeted therapies for the treatment of this disease. Using 2 human PCa tissue microarray cohorts, we first demonstrate that nuclear ERα expression was heterogeneous among patients, being detected in only half of the tumors. Positive nuclear ERα levels were correlated with disease recurrence, progression to metastatic PCa, and patient survival. Using in vitro and in vivo models of the normal prostate and PCa, bulk and single-cell RNA-Seq analyses revealed that estrogens partially mimicked the androgen transcriptional response and activated specific biological pathways linked to proliferation and metabolism. Bioenergetic flux assays and metabolomics confirmed the regulation of cancer metabolism by estrogens, supporting proliferation. Using cancer cell lines and patient-derived organoids, selective estrogen receptor modulators, a pure anti-estrogen, and genetic approaches impaired cancer cell proliferation and growth in an ERα-dependent manner. Overall, our study revealed that, when expressed, ERα functionally reprogrammed PCa metabolism, was associated with disease progression, and could be targeted for therapeutic purposes.

Bioanalytical method development and validation for the quantification of raloxifene hydrochloride from mice plasma by RP-HPLC

Raloxifene hydrochloride (RLX) belongs to the Selective estrogen receptor modulator (SERM) class of drugs, exhibiting diverse affinity to estrogen receptors. The drug is known for its anti-cancer and anti-osteoporosis activity. The current study employs a Reverse Phase High-Performance Liquid Chromatography (RP-HPLC) method that is sensitive and time-efficient for quantitative evaluation of RLX from mice plasma, using tamoxifen citrate as an internal standard (IS). The protein precipitation technique was used to extract the RLX and IS. RLX was separated using a C8 column with an isocratic elution of a mobile phase consisting of acetonitrile and Milli-Q water (pH 3) at a 1 mL/min flow rate. The ultraviolet (UV) detection of the analyte and IS were carried out at 287 nm. The linearity plot was constructed in the range of 100–3200 ng/mL with a correlation coefficient of r2 ≥ 0.9996. The inter-day and intra-day accuracy and precision were found to be within acceptable limits. Stability studies revealed that the analyte remained stable. The validated RP-HPLC method was successfully applied to quantify RLX after oral administration in mice, and the pharmacokinetic (PK) parameters were established. The present RP-HPLC method could be a beneficial tool for the fast and reliable estimation of future PK interactions, PK analysis of formulations, and therapeutic drug monitoring.

Endocrine Resistance in Breast Cancer: The Role of mTOR Signaling in Mediating Resistance to Selective Estrogen Receptor Modulators

Selective estrogen receptor modulators (SERMs) have been widely prescribed and effective as a first-line endocrine therapy to treat ER+ breast cancer. Tamoxifen, the most used SERM in the treatment of breast cancer, has been shown to be effectively anti-proliferative in breast tissue and has made a tremendous contribution to reducing breast cancer mortality. Vast experimental evidence from seven sources supports tamoxifen’s ability in repressing the expression of estrogen-responsive genes involved in cancer growth. The binding of tamoxifen to the estrogen receptor prevents the recruitment of coactivators to the complex and instead promotes the recruitment of corepressors and histone deacetylases, thus inhibiting transcriptional activation of target genes. However, the issue of endocrine resistance remains a predominant problem with this therapy. Sources have found that endocrine resistance can arise due to dysregulations in the mTOR signaling pathway. Experiments have revealed some hope regarding a mechanism by which we can re-sensitize the breast cancer cells to the therapy, notably by knocking down YAP/TAZ or PSAT1 in the mTOR pathway. Despite this discovery, endocrine resistance prevails due to irregularities in additional pathways. Therefore, subsequent research is crucial to identify more targets that, when knocked down, enable re-sensitization of resistant cells, restoring full therapeutic ability of SERMs in afflicted women.

Long-term use of clomiphene in male macroprolactinomas with persistent hypogonadism.

Men with macroprolactinoma can present persistent hypogonadism despite normoprolactinemia achieved with clinical and/or neurosurgical treatment. Usually, testosterone replacement therapy is indicated. Nevertheless, although off-label, clomiphene citrate (CC), a selective estrogen receptor modulator, has also been used, mainly when fertility is an issue. The aim of this study is to evaluate the effectiveness of CC in recovering the gonadal axis in men with macroprolactinoma, with or without hyperprolactinemia, and evaluate its safety as a long-term therapy. This is a retrospective study including 10 men with macroprolactinoma on cabergoline treatment and persistent hypogonadism. All patients received initially 50 mg/d of CC. The median age at diagnosis of prolactinomas was 34 (range, 26-60) years old. All patients were treated with cabergoline at a median maximum dose of 2 (1-7) mg/week, with a median time of treatment of 8.5 (2-15) years. Prolactin was still above the normal range when CC was introduced only in two patients. The mean duration of CC therapy was 3.2 (±2.8) years. Prolactin levels maintained stable (p = 0.252) and testosterone increased (p = 0.027) significantly on CC therapy. Tumor size remained stable. Eight patients (80%) maintained testosterone above 300 ng/dL and were classified as responders. Three responders succeeded in using a lower dose of CC and one of them completed withdrawal CC and maintained eugonadism. There were no side effects or safety concerns reported. CC should be seen as a safe treatment option for men with macroprolactinoma and persistent hypogonadism.

Abstract LB051: Protein kinase C beta 1 (PKCβ1) is allosterically inhibited and paradoxically translocated to the membrane by z-endoxifen

Abstract The protein kinase C (PKC) family of enzymes are indispensable serine-threonine kinases involved in signal pathways implicated in many different cellular processes. Dysregulation of PKC isoforms may contribute to the development and progression of breast cancer. Z-Endoxifen (Z-ENDX), the active metabolite of tamoxifen (TAM) and a selective estrogen receptor modulator (SERM) exhibited potent antitumor activity in endocrine-resistant hormone receptor-positive breast and other gynecologic cancers. Mechanistically, we discovered that ENDX inhibits PKCβI and downstream AKT signaling. Based on insights from our recently determined crystal structure of PKCβI, we investigated the effects of ENDX on PKCβI in estrogen receptor-positive (ER+) breast cancer. In vitro FRET-based biochemical assays revealed that ENDX inhibits the kinase activity of conventional (PKCβI) as well as a novel (PKC;) PKC isoform with a similar IC50. However, the PKCβI catalytic domain was found to be less sensitive to ENDX compared to full-length PKCβI. We identified a multi-domain mechanism of PKC inhibition through an allosteric inhibitory model using X-ray crystallography. Since the spatial assembly of PKC is crucial for its kinase activity, we assessed the effects of ENDX on the intracellular localization of PKCβI using live cell confocal imaging. Sub-cellular tracking of YFP-tagged PKCβI in ER+ MCF7 cells paradoxically revealed that ENDX promoted the translocation of PKCβI to the plasma membrane in both a dose and time-dependent manner. Furthermore, co-treatment with inhibitors of PHLPP phosphatases, which regulate PKC, alleviated this translocation. Based on our prior data demonstrating greater antitumor activity of the Z vs E isomer of ENDX, we discovered that Z-ENDX inhibits PKCβI kinase activity more effectively than its E-isomer using in vitro kinase assays. Further, E-ENDX failed to promote PKCβI translocation to the membrane.Taken together, these results suggest that allosteric effects of Z-ENDX trigger PKCβI recruitment to the plasma membrane where it is normally active yet suppresses its kinase activity. These findings indicate that Z-ENDX induces a non-productive structure of the enzyme and "breaks" the well-known mechanism of PKC activation upon binding to the cell membrane. Moreover, Z-ENDX likely triggers PHLPP-mediated PKCβI dephosphorylation, and ultimately PKCβI degradation, suggesting that Z-ENDX represents a new mechanistic basis for targeting and downregulating PKCβI, and potentially other PKC family members, in cancer cells. This newly discovered function of Z-ENDX likely contributes to its superior anti-cancer effects when compared to TAM and other endocrine therapies. Citation Format: Sayantani Sarkar Bhattacharya, Huy V. Huynh, Jasmin K. Farmakes, Taylor L. Witter, Elizabeth S. Bruinsma, Swaathi Jayaraman, Anh T. Cong, John R. Hawse, Matthew P. Goetz, Matthew J. Schellenberg. Protein kinase C beta 1 (PKCβ1) is allosterically inhibited and paradoxically translocated to the membrane by z-endoxifen [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB051.

Abstract CT075: A Phase 1 trial evaluating AC699, an orally bioavailable chimeric estrogen receptor degrader, in patients with advanced or metastatic breast cancer

Abstract Background The role of estrogen receptor (ER) signaling in driving breast carcinogenesis is well established, and endocrine therapy has been a mainstay in the treatment of patients with ER-positive advanced or metastatic breast cancer for decades. Aromatase inhibitors, selective estrogen receptor modulators, and selective ER degraders (SERDs) such as fulvestrant, and more recently elacestrant, are integral components of the therapeutic strategy for patients with ER-positive breast cancer. However, unmet medical need persists in this patient population, due to suboptimal clinical outcomes and the development of resistance to therapy. E3 ligase-engaged chimeric degraders represent a technological advance with the potential to induce potent and deeper ER degradation. Utilizing Accutar's proprietary Protein-Protein Interaction Targeting Chimeras (PPI-TAC) platform, AC699 was designed as a novel chimeric degrader targeting ERα. By effectively linking an ER ligand to an E3-ligase recruiting ligand, AC699 brings ERα in proximity to an E3 ligase, resulting in ubiquitination and subsequent degradation of ERα. Chimeric ER degraders possess the unique advantage of degrading the ER protein without the inherent risk of activating an ER signal. Moreover, these molecules are not degraded alongside the target protein, allowing for their efficient recycling within the cell. This direct mechanism enables chimeric ER degraders to achieve potent ER degradation with increased specificity, thereby potentially providing a higher therapeutic index compared to SERDs. Study Description The AC699-001 trial is a first in human Phase 1 dose escalation study (NCT05654532) which will enroll up to 60 patients with locally advanced or metastatic ER-positive, human epidermal growth factor receptor 2-negative, breast cancer. Patients must have received at least two prior lines of endocrine treatment, or at least one prior line, if combined with a CDK4/6 inhibitor. Prior chemotherapy is not required but must not exceed three prior lines of cytotoxic treatment. Patients must have at least one measurable lesion or at least one predominantly lytic bone lesion. AC699 is administered orally, once daily, with doses ranging from 100 mg to 600 mg in a standard 3+3 dose escalation design. The primary objective is evaluation of the safety and tolerability of AC699. Secondary objectives include assessment of preliminary anti-tumor activity and characterization of the pharmacokinetic profile of single and multiple doses of AC699. Enrollment began in December 2022 and a total of 5 sites have been activated in the United States. Citation Format: Rachel M. Layman, Manish R. Patel, David Cosgrove, Michael Danso, Nancy Mota, Marjorie E. Zettler, Katherine C. Pehlivan, Erika Hamilton. A Phase 1 trial evaluating AC699, an orally bioavailable chimeric estrogen receptor degrader, in patients with advanced or metastatic breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT075.

Tamoxifen protects photoreceptors in the sodium iodate model

Because the selective estrogen receptor modulator tamoxifen was shown to be retina-protective in the light damage and rd10 models of retinal degeneration, the purpose of this study was to test whether tamoxifen is retina-protective in a model where retinal pigment epithelium (RPE) toxicity appears to be the primary insult: the sodium iodate (NaIO3) model. C57Bl/6J mice were given oral tamoxifen (in the diet) or the same diet lacking tamoxifen, then given an intraperitoneal injection of NaIO3 at 25 mg/kg. The mice were imaged a week later using optical coherence tomography (OCT). ImageJ with a custom macro was utilized to measure retinal thicknesses in OCT images. Electroretinography (ERG) was used to measure retinal function one week post-injection. After euthanasia, quantitative real-time PCR (qRT-PCR) was performed. Tamoxifen administration partially protected photoreceptors. There was less photoreceptor layer thinning in OCT images of tamoxifen-treated mice. qRT-PCR revealed, in the tamoxifen-treated group, less upregulation of antioxidant and complement factor 3 mRNAs, and less reduction in the rhodopsin and short-wave cone opsin mRNAs. Furthermore, ERG results demonstrated preservation of photoreceptor function for the tamoxifen-treated group. Cone function was better protected than rods. These results indicate that tamoxifen provided structural and functional protection to photoreceptors against NaIO3. RPE cells were not protected. These neuroprotective effects suggest that estrogen-receptor modulation may be retina-protective. The fact that cones are particularly protected is intriguing given their importance for human visual function and their survival until the late stages of retinitis pigmentosa. Further investigation of this protective pathway could lead to new photoreceptor-protective therapeutics.

Long-Term Oral Tamoxifen Administration Decreases Brain-Derived Neurotrophic Factor in the Hippocampus of Female Long-Evans Rats.

Tamoxifen, a selective estrogen receptor modulator (SERM), is commonly used as an adjuvant drug therapy for estrogen-receptor-positive breast cancers. Though effective at reducing the rate of cancer recurrence, patients often report unwanted cognitive and affective side effects. Despite this, the impacts of chronic tamoxifen exposure on the brain are poorly understood, and rodent models of tamoxifen exposure do not replicate the chronic oral administration seen in patients. We, therefore, used long-term ad lib consumption of medicated food pellets to model chronic tamoxifen exposure in a clinically relevant way. Adult female Long-Evans Hooded rats consumed tamoxifen-medicated food pellets for approximately 12 weeks, while control animals received standard chow. At the conclusion of the experiment, blood and brain samples were collected for analyses. Blood tamoxifen levels were measured using a novel ultra-performance liquid chromatography-tandem mass spectrometry assay, which found that this administration paradigm produced serum levels of tamoxifen similar to those in human patients. In the brain, brain-derived neurotrophic factor (BDNF) was visualized in the hippocampus using immunohistochemistry. Chronic oral tamoxifen treatment resulted in a decrease in BDNF expression across several regions of the hippocampus. These findings provide a novel method of modeling and measuring chronic oral tamoxifen exposure and suggest a putative mechanism by which tamoxifen may cause cognitive and behavioral changes reported by patients.

Abstract 3046: The estrogen signaling pathway reprograms prostate cancer cell metabolism and supports proliferation and disease progression

Abstract Just as the androgen receptor (AR), the estrogen receptor α (ERα) is expressed in the prostate and is thought to influence prostate cancer (PCa) biology. Yet, the incomplete understanding of ERα cellular functions in PCa hinders our ability to fully comprehend its clinical relevance and restricts the repurposing of estrogen-targeted therapies for treatment of this disease. Using two human PCa tissue microarray cohorts, we first demonstrated that nuclear ERα expression was heterogeneous between patients, being only detected in half of tumors. Positive nuclear ERα levels were correlated with disease recurrence, progression to metastatic PCa, and patient survival. Using in vitro and in vivo models of the normal prostate and PCa, bulk and single cell RNA-seq analyses revealed that estrogens partially mimic the androgen transcriptional response and induce specific biological pathways linked to cellular proliferation and metabolism. Bioenergetic flux assays and metabolomics confirmed regulation of cancer metabolism by estrogens, supporting proliferation. Using cancer cell lines and patient-derived organoids, selective estrogen receptor modulators, a pure anti-estrogen, and genetic approaches impaired cancer cell proliferation and growth in an ERα-dependent manner. Overall, our study revealed that, when expressed, ERα functionally reprograms PCa metabolism, is associated with disease progression, and could be targeted for therapeutic purposes. Citation Format: Camille Lafront, Lucas Germain, Gabriel H. Campolina-Silva, Cindy Weidmann, Line Berthiaume, Hélène Hovington, Hervé Brisson, Cynthia Jobin, Lilianne Frégeau-Proulx, Raul Cotau, Kevin Gonthier, Aurélie Lacouture, Patrick Caron, Claire Ménard, Chantal Atallah, Julie Riopel, Éva Latulippe, Alain Bergeron, Paul Toren, Chantal Guillemette, Martin Pelletier, Yves Fradet, Clémence Belleannée, Frédéric Pouliot, Louis Lacombe, Éric Lévesque, Étienne Audet-Walsh. The estrogen signaling pathway reprograms prostate cancer cell metabolism and supports proliferation and disease progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3046.

Abstract 2244: Accelerated aging associated with cancer characteristics and treatments among breast cancer survivors

Abstract There are currently approximately four million breast cancer (BC) survivors in the US. BC survivors may experience accelerated aging, with greater physical dysfunction and cognitive decline than cancer-free women, potentially due to the detrimental effects of BC and/or its treatments (Tx). However, the aging trajectory after BC diagnosis has not been fully elucidated. A biological age measure, PhenoAge acceleration (PAA), derived from chronological age and nine clinical blood chemistry biomarkers, has been associated with aging-related health outcomes and mortality in the general population. Our study aims to evaluate PAA among BC patients by clinical characteristics, cancer Tx, and medications (chemotherapy and endocrine therapy drugs). The study included 1264 BC patients (age 54.7±11.7) recruited at Vanderbilt University Medical Center in 2004-2021. BC-related information and lab test results were obtained from the tumor registry and electronic health records. The differences in PAA (ΔPAA) by BC stage, grade, subtype, Tx, and medications at multiple time points were evaluated using linear mixed models, with the time interval between diagnosis and PAA assessments as a natural spline, and its interaction with the exposures under study as covariates. Associations of PAA with Tx and medications were estimated with adjustment for other Tx and medications. At 10 years post-diagnosis, stage III/IV (vs 0) and intermediate- and high- (vs low-) grade BC were associated with a higher PAA of 4.48 (p<0.001), 1.26 (p=0.03), and 1.95 (p=0.001), respectively; triple-negative (vs hormone receptor+/Her2-) BC was associated with a lower PAA (ΔPAA=-1.96, p=0.004). Compared with surgery, alone or with radiotherapy, surgery plus chemotherapy was associated with a higher PAA at 1 year (ΔPAA ranging from 1.96, p=0.03 to 4.61, p<0.001), while surgery plus endocrine therapy was associated with a higher PAA at 10 years post-diagnosis (ΔPAA ranging from 1.70, p=0.04 to 2.75, p=0.006). The associations of PAA with most chemotherapy agents diminished over time, reverting to negative or null at 10 years. Antimetabolites, on the other hand, were associated with an increased PAA at 2 years (ΔPAA=2.62, p<0.001) which increased further at 10 years post-diagnosis (ΔPAA=7.26, p<0.001). Endocrine therapy and PAA association at 10 years post-diagnosis was likely driven by aromatase inhibitors (AI) (ΔPAA=1.53, p<0.001). Selective estrogen receptor modulators were inversely associated with PAA at year 10 (ΔPAA=-1.03, p=0.01). Additional adjustment for BC stage, grade, and subtype did not materially change the results for Tx and medications. Our study found that BC patients had accelerated aging up to 10 years post-diagnosis, especially those with stage III/IV and high/intermediate-grade BC. The aging trajectory varied by cancer Tx and medications; antimetabolites and AI might accelerate aging in long term BC survivors. Citation Format: Cong Wang, Jill B. De Vis, Kirsten Nguyen, Brigitte Jia, Mason Alford, Anuradha Bapsi Chakravarthy, Xiao-Ou Shu. Accelerated aging associated with cancer characteristics and treatments among breast cancer survivors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2244.

Abstract 776: Change in background contrast enhancement category on abbreviated breast MRI with administration of 6 months of bazedoxifene and conjugated estrogen vs wait list control

Abstract Background MRI background contrast enhancement (BPE) has found to be a marker of breast cancer risk providing information beyond that provided by assessment of breast density. BPE is qualitatively classified into categories that correspond to BPE estimates as minimal, <25% BPE; mild, 25-50% BPE; moderate, 50-75% BPE; and marked, >75% BPE. We divided minimal into minimal and almost none (≤5%). We conducted a feasibility study of change in BPE after 6 months of the selective estrogen receptor modulator bazedoxifene (BZA) 20 mg + conjugated estrogen (CE) 0.45 mg marketed commercially as Duavee™ for relief of hot flashes and prevention of osteoporosis in postmenopausal women. Methods STUDY00145121 started 5-27-2020 with randomization to 6 months of Duavee™ vs waitlist control but was stopped after 11 entrants because participants were unable to receive follow-up breast MRIs due to COVID and Duavee™ became unavailable. STUDY0014761 was opened in early 2022 when a source of BZA was found. Doses of BZA and CE were the same as Duavee™ but given as two pills instead of one. 16 women have been randomized to 6 months of BZA/CE vs a wait list control between 2-14-2022 and 9-19-2023. Inclusion criteria are postmenopausal women ages 45-65 at increased risk for breast cancer, BMI < 36 kg/m2 and having current vasomotor symptoms. Participants had a blood draw, 3D mammogram, and abbreviated breast MRI at baseline and the studies were repeated at 6 months. Volumetric density was assessed by Volpara™ fully automated software. Research evaluation of abbreviated MRI background parenchymal contrast enhancement (BPE) was assessed by 5 categories as almost none, minimal, mild, moderate, and marked. BPE was evaluated by a single radiologist blinded to treatment assignment and compared to the 4-category clinical assessment. Results A total of 27 women have been entered in these studies. Six were not evaluable from STUDY00145121 because of the inability to perform 6-month MRI. Two women on STUDY0014761 are not endpoint evaluable due to early drop out and 3 have not yet completed study. A total of 16 women have completed the 6-month portion of the study and abbreviated MRI, with median age 55 (range 47-62) and median BMI 26 kg/m2 (20-33 kg/m2). At baseline, BPE were 3 almost none, 4 minimal, 8 mild, 1 moderate, and 0 marked. There was little correlation between absolute baseline mammographic fibroglandular volume and baseline BPE. A shift in BPE category using the 5-category assessment was noted in 6/11 women (all but one decreased) randomized to BZA +CE and 2/5 women (both decreased) on waitlist. The one increase and four categorical decreases would not have been detected without expansion of BPE to a 5-category system. Conclusion Using the 5-category classification, abbreviated MRI BPE may have promise as a response biomarker in prevention trials for postmenopausal high-risk women. Citation Format: Carol J. Fabian, Onilisa Winblad, Amy Kreutzjans, Krystal Pittman, Christy Altman, Kandy R. Powers, Mary McCarthy, Lauren Nye, Bruce F. Kimler. Change in background contrast enhancement category on abbreviated breast MRI with administration of 6 months of bazedoxifene and conjugated estrogen vs wait list control [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 776.

Autophagy and senescence facilitate the development of antiestrogen resistance in ER positive breast cancer.

Estrogen receptor positive (ER+) breast cancer is the most common breast cancer diagnosed annually in the US with endocrine-based therapy as standard-of-care for this breast cancer subtype. Endocrine therapy includes treatment with antiestrogens, such as selective estrogen receptor modulators (SERMs), selective estrogen receptor downregulators (SERDs), and aromatase inhibitors (AIs). Despite the appreciable remission achievable with these treatments, a substantial cohort of women will experience primary tumor recurrence, subsequent metastasis, and eventual death due to their disease. In these cases, the breast cancer cells have become resistant to endocrine therapy, with endocrine resistance identified as the major obstacle to the medical oncologist and patient. To combat the development of endocrine resistance, the treatment options for ER+, HER2 negative breast cancer now include CDK4/6 inhibitors used as adjuvants to antiestrogen treatment. In addition to the dysregulated activity of CDK4/6, a plethora of genetic and biochemical mechanisms have been identified that contribute to endocrine resistance. These mechanisms, which have been identified by lab-based studies utilizing appropriate cell and animal models of breast cancer, and by clinical studies in which gene expression profiles identify candidate endocrine resistance genes, are the subject of this review. In addition, we will discuss molecular targeting strategies now utilized in conjunction with endocrine therapy to combat the development of resistance or target resistant breast cancer cells. Of approaches currently being explored to improve endocrine treatment efficacy and patient outcome, two adaptive cell survival mechanisms, autophagy, and "reversible" senescence, are considered molecular targets. Autophagy and/or senescence induction have been identified in response to most antiestrogen treatments currently being used for the treatment of ER+ breast cancer and are often induced in response to CDK4/6 inhibitors. Unfortunately, effective strategies to target these cell survival pathways have not yet been successfully developed. Thus, there is an urgent need for the continued interrogation of autophagy and "reversible" senescence in clinically relevant breast cancer models with the long-term goal of identifying new molecular targets for improved treatment of ER+ breast cancer.

Lomitapide as a Potential Estrogen Receptor Inhibitor: A Computational Drug Repurposing Study

Objective: Estrogen receptor (ER) inhibitors have significant therapeutic potential for hormone-dependent cancers and related disorders. Tamoxifen, a well-known selective estrogen receptor modulator, has been widely used as adjuvant therapy for estrogen receptor-positive breast cancer. However, tamoxifen may exhibit a tendency to develop resistance with prolonged usage and particularly elevate the risk of uterine cancer. Therefore, there is a need for the discovery and development of new ER modulators or inhibitors. In this study, we identified potential estrogen receptor inhibitors through computational drug repositioning.
 
 Methods: A set of 2048 compounds, encompassing FDA-approved drugs and active metabolites, were subjected to molecular docking, molecular dynamics simulations, and free energy calculations to evaluate their interaction with estrogen receptor α (ERα).
 
 Results: Among the compounds evaluated, conivaptan, atogepant, and lomitapide exhibited the highest affinities for ERα. Lomitapide displayed a superior docking score (-12 kcal/mol) compared to the established ER inhibitor, tamoxifen (-10 kcal/mol). Further investigation using molecular dynamics simulations and free energy calculations disclosed lomitapide's heightened binding affinity of -380.727 kJ/mol, surpassing tamoxifen's binding affinity of -352.029 kJ/mol.
 
 Conclusion: This comprehensive computational exploration underscores lomitapide's potential as a compelling candidate with an envisaged stronger estrogen receptor affinity than the acknowledged standard, tamoxifen. To validate lomitapide's promise as a novel ER inhibitor, essential in vitro and in vivo studies are suggested. These investigations will provide essential insights into lomitapide's reposition in addressing the challenges tied to hormone-dependent cancers and associated maladies.

Molecular Docking and ADMET Analysis Strategy-Based Stability Indicating RP-HPLC-PDA Method Development and Validation of Toremifene.

The purpose of this research is to develop an analytical method and validate it according to ICH guidelines for the estimation of Toremifene by RP-HPLC-PDA with molecular docking and ADMET analysis. From molecular docking, it came to know the receptor affinity specifically to estrogen receptors (ERα and ERβ), which are responsible for cancer therapy. ADMET analyses secure its therapeutic potential as well safety of the drug. An isocratic method has developed by RP-HPLC-PDA (AGILENT 1100) with symmetry of 100 mm x 4.6 mm x 5 μm particle size C18 column and optimise mobile phase is methanol: 0.1% OPA (orthophosphoric acid) water ratio of 43:57% v/v. Under different conditions like acidic, alkaline, oxidative, and neutral environments, toremifene was tested for degradation. The developed method is validated in accordance with ICH guidelines. A calibration curve with an r2 value of 0.9987 has been prepared across the range of 10 to 50 μg/ml with five standard dilutions. The retention time of the drug is 5.575 minutes. The validation results are system suitability (%RSD-0.76), inter-day precision (%RSD 0.14-0.29), intraday precision (%RSD 0.08-0.34), accuracy (%RSD 0.16-0.96), and robustness (%RSD 0.16-0.35). In different intended conditions, four peaks are in 1 N HCl, two peaks in 1 N NaOH, three peaks in 10% H2O2 (1hr), and one peak in neutral. Toremifene, a Selective Estrogen Receptor Modulator (SERM), Drug pharmacokinetic properties and receptor binding affinity results are helpful in designing the analytical method. Developing the RP-HPLC-PDA method is found to be novel, simple and precise. It could be used for testing toremifene in bulk and pharmaceutical tablet dosage forms in quality control, as well as stability tests.

Association between pharmacotherapy and secondary vertebral fracture managed with a brace in a real-world setting: A nationwide database study in Japan.

This retrospective cohort study assessed the association between the incidence of secondary vertebral fracture managed with a brace (SVF) and pharmacotherapy. The association between the incidence of SVF and the presence, type, and medication possession ratio (MPR) of pharmacotherapy was investigated using medical insurance data acquired from the National Database of Health Insurance Claims and Specific Health Checkups of Japan. The data of female patients (n = 637 303) were analyzed. The 2-year incidence of SVF was 73.5 per 10 000 patients (n = 4687). Approximately 0.73% of patients without medications and 0.74% with medications had SVF. Patients taking bisphosphonates (0.87), denosumab (0.77), and selective estrogen receptor modulators (0.88) had significantly lower standardized incidence ratios (SIRs) than patients not taking medications after the occurrence of primary fracture; meanwhile, patients taking parathyroid hormone medications had considerably higher SIRs than those not taking medications. The non-SVF group (59.1%) had a significantly higher mean MPR than the SVF group (55.5%). Patients taking denosumab in the non-SVF group (68.2%) had the highest mean MPR. The proportion of patients taking denosumab with an MPR of ≥80% in the non-SVF group was significantly higher than that in the SVF group. Patients taking medications were at a lower risk of developing SVF than those not taking medications. Although this study did not compare the medications' SVF prevention effects, patients taking denosumab had a 0.77 SIR of SVF in Japan. The effect of pharmacotherapy on SVF prevention might be affected by the MPR of each medication. Geriatr Gerontol Int 2024; 24: 390-397.

The 2023 Guidelines for the management and treatment of glucocorticoid-induced osteoporosis

IntroductionAlthough synthetic glucocorticoids (GCs) are commonly used to treat autoimmune and other diseases, GC induced osteoporosis (GIOP) which accounts for 25% of the adverse reactions, causes fractures in 30–50% of patients, and markedly decreases their quality of life. In 2014, the Japanese Society for Bone and Mineral Research (JSBMR) published the revised guidelines for the management and treatment of steroid-induced osteoporosis, providing the treatment criteria based on scores of risk factors, including previous fractures, age, GC doses, and bone mineral density, for patients aged ≥18 years who are receiving GC therapy or scheduled to receive GC therapy for ≥3 months.Materials and methodsThe Committee on the revision of the guidelines for the management and treatment of GIOP of the JSBMR prepared 17 clinical questions (CQs) according to the GRADE approach and revised the guidelines for the management and treatment of GIOP through systematic reviews and consensus conferences using the Delphi method.ResultsBisphosphonates (oral and injectable formulations), anti-RANKL antibody teriparatide, eldecalcitol, or selective estrogen receptor modulators are recommended for patients who has received or scheduled for GC therapy with risk factor scores of ≥3. It is recommended that osteoporosis medication is started concomitantly with the GC therapy for the prevention of fragility fractures in elderly patients.ConclusionThe 2023 guidelines for the management and treatment of GIOP was developed through systematic reviews and consensus conferences using the Delphi method.

Combination clomiphene citrate and anastrozole duotherapy improves semen parameters in a multi-institutional, retrospective cohort of infertile men.

In men with impaired semen parameters, empiric medical therapies such as clomiphene citrate, a selective estrogen receptor modulator (SERM), and anastrozole, a selective aromatase inhibitor, are often employed. The effects of jointly administering these agents on semen parameters are not well understood. Here, we describe the findings of our multi-center, retrospective cohort study of men with idiopathic primary or secondary infertility. Twenty-one men were treated with combination therapy (anastrozole and clomiphene) and 69 men were treated with monotherapy (anastrozole). Patients with pre-treatment normozoospermia and recent or current exogenous testosterone therapy were excluded. Baseline and post-treatment semen and sex hormone parameters were compared among groups. The median follow-up duration was 91 days [interquartile range (IQR), 64-117 days]. Following treatment, 43% of men in the combination therapy group demonstrated normozoospermia, compared to 25% in the monotherapy group. Furthermore, men in the combined group demonstrated marked improvements in total motile sperm count (TMSC) [11.3 vs. 2.1 million (M), P=0.03]. There were no significant differences in hormone levels among the two groups following treatment. Combination therapy with clomiphene citrate and anastrozole was associated with modest benefits in post-treatment semen parameters, when compared to anastrozole monotherapy. These benefits may contribute to improvements in pregnancy outcomes with less invasive assisted reproductive technologies, such as intrauterine insemination (IUI). Future investigations with larger sample sizes and prospective study designs are necessary.

Should ultrasound assessment of the endometrium be necessary in patients treated with Tamoxifen?

Tamoxifen is a nonsteroidal selective estrogen receptor modulator that is used mainly for adjuvant treatment of estrogen receptor-positive breast cancer. However, tamoxifen, due to its estrogen-mimicking effects, has been linked to various uterine conditions including menstrual irregularities, and endometrial cancer. Considering that in women taking tamoxifen, ultrasonographical endometrial thickness can be increased without an underlying pathology and that the tamoxifen induces only an extra endometrial cancer in 1 per 1000 women per year of use, patients undergoing tamoxifen treatment don't typically undergo regular examinations of the endometrium, including ultrasonography. Routine ultrasonographic screening for endometrial lesions could result in excessive intervention for non-symptomatic endometrial conditions, undue stress, and might even negatively affect patients' adherence to tamoxifen therapy, which is crucial for reducing breast cancer recurrence and mortality. Nevertheless, if any unusual bleeding arises, an endometrial evaluation is necessary.