Selective Estrogen Receptor Modulators Research Articles

Clinical outcomes of round spermatid injection versus intra-cytoplasmic sperm injection: The potential role of hormonal pretreatment in male patients with non-obstructive azoospermia.

Round spermatid injection (ROSI) into oocytes offers men with non-obstructive azoospermia (NOA) the opportunity to have biological offspring in cases where mature spermatozoa are not detected. However, the clinical outcomes of ROSI remains poor. This study compares the outcomes of ROSI with intracytoplasmic sperm injection (ICSI) and investigates the effect of hormonal pretreatment. This retrospective cohort study enrolled infertile couples undergoing either ROSI or ICSI at the reproductive center in Taipei Veterans General Hospital. The administration of selective estrogen receptor modulators, gonadotropins, and aromatase inhibitors in male patients were collected. Relevant hormonal markers and biochemical parameters were determined. The outcomes of ROSI and ICSI were assessed based on fertilization rate, implantation rate, and live birth rate. A total of 36 couples were recruited in the ROSI group, whereas 39 couples were recruited in the ICSI group for the analysis. Patients in each group demonstrated similar characteristics, except for a higher proportion of male patients in the ROSI group who were pretreated with anastrozole. The fertilization rate and implantation rate were similar between ROSI and ICSI groups after adjusting for confounding variable. The live birth rate was significant lower in the ROSI group (8.3%) than in the ICSI group (30.8%) before and after adjusting for confounding variable. ROSI demonstrated fertilization and implantation rates comparable to those of ICSI for male patient with NOA undergoing testicular sperm extraction surgery. Further studies evaluating the effect of anastrozole administration on ROSI outcomes are warrant.

Pharmacologic Induction of ERα SUMOylation Disrupts Its Chromatin Binding.

Estrogen receptor α (ERα)-positive breast cancer patients are typically treated with ERα inhibitors, including selective estrogen receptor modulators (SERMs) and selective estrogen receptor degraders (SERDs). However, the distinct pharmacological properties of various ERα inhibitors remain incompletely understood. In this study, we employed formaldehyde cross-linking followed by ERα immunoprecipitation and mass spectrometry to reveal that fulvestrant, the first FDA-approved SERD, induces the interaction between ERα and SUMO E3 ligases PIAS1 and PIAS2. Biochemical and genomic assays confirmed that fulvestrant induces SUMOylation of ERα, which inhibits ERα's binding to chromatin DNA. In addition, raloxifene (a SERM) and elacestrant (the first FDA-approved oral SERD) were identified as compounds that similarly induce ERα SUMOylation and inhibit its chromatin interaction. Our findings reveal a mechanism by which select ERα inhibitors disrupt ERα function through SUMOylation, offering insights for the development of next-generation ERα-targeted therapies.

Molecular insights into genistein-NSAID hybrids—synthesis, characterisation and DFT study

AbstractGenistein (GEN) is one of the pharmaceutically valuable phenolic compounds, which belongs to the isoflavone group of flavonoids and is a natural phytohormone found mainly in soybeans and red clover. It affects estrogen receptors, functioning as a selective estrogen receptor modulator (SERM) with anti-inflammatory and antioxidant activity. The presence of reactive phenolic groups in genistein provides an opportunity to expand its structure by introducing components responsible for anti-inflammatory properties. Such an innovative combination of a compound with anticancer and antioxidant potential with an anti-inflammatory compound (NSAID) may lead to interesting new derivatives with dual mechanisms of biological action. The synthesis and characterisation of genistein-NSAID hybrid compounds (ibuprofen, ketoprofen, naproxen, flurbiprofen) was conducted, together with a comprehensive structural and quantum chemistry DFT (density functional theory) computational analysis allowing the description of 1H-NMR and 13C-NMR spectroscopic properties of the starting compounds and the resulting hybrids. The study resulted in the formation of seven hybrid GEN-NSAID derivatives. In the case of ibuprofen, ketoprofen and flurbiprofen, a mixture of isomeric hybrid GEN-4’-NSAID and GEN-7-NSAID derivatives was obtained, whereas, for naproxen, only GEN-4’-NSAID was formed. The structural characteristics of the resulting compounds were determined using MS, IR, 1H-NMR and 13C-NMR spectroscopic methods. The most accurate DFT computational methods for predicting 1H-NMR and 13C-NMR spectra were also established with statistical parameters to assess their accuracy.

Compared Antileishmanial Activity of Clomiphene and Tamoxifen.

Drug repositioning is an efficient strategy to search for new treatment alternatives that is especially valuable for neglected parasitic diseases such as leishmaniasis. Tamoxifen and raloxifene are selective estrogen receptor modulators (SERMs) that have shown antileishmanial activity. Clomiphene is a SERM structurally similar to tamoxifen, whose antileishmanial potential is unknown. That is why the objective of the present work was to evaluate its antileishmanial activity in vitro and in vivo in comparison with tamoxifen. The inhibitory effect against promastigotes of L. amazonensis, L. major, and L. mexicana was evaluated for both compounds, as well as the cytotoxicity against mouse peritoneal macrophages, the growth inhibitory activity in intracellular amastigotes of L. mexicana, and the in vivo activity in mice experimentally infected with L. mexicana. Clomiphene was about twice as active as tamoxifen against both promastigotes and intracellular amastigotes, with IC50 values of 1.7-3.3 µM for clomiphene and 2.9-6.4 µM for tamoxifen against all three species of promastigotes and 2.8 ± 0.2 µM and 3.7 ± 0.3 µM, respectively, against L. mexicana amastigotes. Clomiphene structurally affected several parasite organelles in a concentration-dependent fashion, leading to the death of both promastigotes and intracellular amastigotes. Interestingly, the macrophage host cell did not appear damaged by any of the clomiphene concentrations tested. With oral administration at 20 mg/kg for 14 days, both compounds showed similar effects in terms of reducing the growth of the lesions, as well as the weight of the lesions and the parasite load at the end of the follow-up period. The results showed the potential of SERMs as antileishmanial drugs and support further testing of clomiphene and other compounds of this pharmacological group.

Evaluation of tamoxifen analogues as potential estrogen receptor alpha inhibitors for breast cancer treatment: A computational approach

Estrogen receptors, particularly ERα, play a key role in breast cancer progression, making them prime targets for therapeutic intervention. Tamoxifen (TAM), a selective estrogen receptor modulator (SERM), has been widely used for the treatment of ER+ breast cancer; however, its clinical application is limited by side effects and the emergence of resistance. This study aims to identify and evaluate TAM analogues with improved efficacy and reduced side effects by employing molecular docking and molecular dynamics (MD) simulations. Droloxifene, endoxifen, and afimoxifene emerged as promising candidates, exhibiting strong binding affinities with ERα, as indicated by highly negative binding energy (BE) values in docking simulations. MD simulations further validated the stability of the complexes formed between these analogues and ERα, with low root mean square deviation (RMSD) values and stable radius of gyration (Rg) profiles. Root mean square fluctuation (RMSF) analysis revealed balanced flexibility, with droloxifene and afimoxifene showing optimized flexibility for stable binding. Hydrogen bond analysis indicated more stable interactions between these analogues and ERα compared to TAM, suggesting enhanced binding affinity. MM/GBSA binding free energy analysis confirmed the high affinity of these analogues, with droloxifene displaying the most effective binding free energy (ΔGtotal) value. ADMET profiling suggests that droloxifene and endoxifen have superior pharmacokinetic properties relative to TAM. Overall, droloxifene, endoxifen, and afimoxifene represent promising alternatives to TAM, with the potential for further clinical development in breast cancer treatment. Experimental validation in cell-based and in vivo models will be crucial in future studies to confirm their efficacy and safety profiles.

Bleeding vs Thrombosis: Treatment Strategy for Women Having Large Uterine Fibroids and DVT

Large uterine fibroids (UFs) are clonal neoplasms of the uterus that form during the mid and late-aged women. Such women generally consume oral contraceptive pills, tranexamic acid, or NSAIDS to manage heavy menstrual bleeding (HMB) and associated complications while waiting for a conclusive procedure or avoiding hysterectomy. The procoagulant effect of these medicinal agents can result in venous stasis of the lower limbs, leading to deep vein thrombosis (DVT), a challenging complication with HMB. We examine the complicated state of heavy bleeding with thrombosis and explore better management options. It has been seen that women with hypothyroidism have an increased risk of getting DVT due to an alteration in the coagulation system. These incidences are mostly associated with higher uterine weight, which is related to the extrinsic compression of the inferior vena cava. In such cases, the occurrence of postoperative thrombosis is riskier if hysterectomy/myomectomy is the only option. Utilization of appropriate anticoagulants with modification of the steroid-hormone system using hormone agonists or antagonists (e.g., levonorgestrel intrauterine system, high-dose progestin-only therapy, danazol, aromatase inhibitors, Vitamin-D supplements or selective estrogen receptor modulators) could be an effective technique, but adverse consequences of continued use should be monitored. More research is needed into the basic biology associated with the role of growth factors and genetic alterations in these malignancies. The development of new leiomyomas following conservative therapy is also a significant issue.

Novel Delivery Systems of Raloxifene Hydrochloride for Improved Bioavailability and Therapeutic Efficacy: A Review

Raloxifene hydrochloride belongs to the selective estrogen receptor modulator category. Initially, US FDA approved its use for the prevention and treatment of osteoporosis in postmenopausal women. Later, raloxifene hydrochloride was also approved for the prevention of invasive breast carcinoma in post-menopausal women under the high-risk category. Despite its immense and diverse therapeutic potential, the oral bioavailability of raloxifene hydrochloride is only ~ 2%. The factors responsible for the poor bioavailability of raloxifene hydrochloride include its amphiphobic nature, para-glycoprotein pump-mediated efflux in the intestine, and high pre-systemic glucuronidation. In the past two decades, multiple novel delivery systems, viz. lipid-based nanocarriers, polymeric nanoparticles, polymer-lipid hybrid nanoparticles, micelles, and mixed micelles, have been developed to overcome its drawbacks. Moreover, inclusion complex, phospholipid complex, and solid dispersion have also been developed to improve its solubility and dissolution rate. Further, some research groups successfully explored non-peroral routes like nasal and transdermal for augmenting the raloxifene hydrochloride bioavailability and its therapeutic efficacy. Hence, the principal objective of this review paper is to critically analyze all the delivery systems developed for raloxifene hydrochloride with their advantages and limitations. In addition, a detailed discussion of the physicochemical and pharmacokinetic parameters of raloxifene hydrochloride has been included in this paper. An in-depth understanding of these parameters will assist formulation scientists in developing efficient delivery systems in the future. In conclusion, the literature review revealed that the nanoparticulate systems successfully augmented the raloxifene hydrochloride bioavailability and therapeutic efficacy in pre-clinical experiments. However, future clinical trials should be conducted to assess their safety and therapeutic efficacy for rapid preclinical to clinical translation.

6594 A Rare Case of Clomiphene Induced De Quervain’s Subacute Thyroiditis

Abstract Disclosure: A. Abdelhameed: None. M. Mortagy: None. A. Elsandouby: None. A. Ghaffar: None. Introduction: Clomiphene is a selective estrogen receptor modulator that stimulates LH release by inhibiting negative feedback on the hypothalamic-pituitary axis. De Quervain’s subacute granulomatous thyroiditis is usually caused by viral infections and less often is drug-induced. We present a case of possible subacute thyroiditis induced by clomiphene. To the best of ourknowledge, this association has not been reported before. Case presentation: A 35-year-old female with a past medical history of unexplained infertility presents to the general medicine clinic with severe neck pain for the last 5 days. Her neck pain started 2 days after the completion of the clomiphene course for induction of ovulation (50 mg daily for 5 days). She denied upper respiratory symptoms. She had an extremely tender thyroid with no palpable nodules. Throat was clear. She was clinically euthyroid with no rash or itching. TSH was 3.9 mIU/L (TSH was normal 6 months prior). ESR was 40 mm/hr. Thyroid ultrasound was unremarkable. She was treated with Ibuprofen for subacute thyroiditis. In the first 2 weeks, the patient complained of increased anxiety. In the next month, she had a missed menstrual cycle. Her pain and tenderness resolved after 50 days. Repeat TSH was 2.4 mIU/L. The patient was advised not to retake clomiphene. Discussion: This is a typical presentation of subacute thyroiditis as persistent thyroid pain and tenderness with elevated ESR. The patient didn’t have the classical symptoms of preceding viral infection. However, her symptoms began immediately after completion of clomiphene course suggesting a temporal relation. The patient didn’t have any history of thyroid problems. She had increased anxiety initially followed by a missed period which suggests clinical thyroid dysfunction.Clomiphene has been associated in the literature with an increased risk of thyroid cancer. Uncontrolled thyroid dysfunction is a contraindication for clomiphene use. This might suggest an interaction between clomiphene and thyroid homeostasis. Subacute thyroiditis could be caused by drugs (e.g., lithium and amiodarone). This suggests that other drugs could lead to subacute thyroiditis such as clomiphene in our case. Conclusion: Clinicians should be aware that clomiphene could be associated with thyroid disorders such as subacute thyroiditis. It is also important to note that thyroid dysfunction is a contraindication for clomiphene use. Presentation: 6/3/2024

8018 Improving Anti-Breast Cancer Activities by Optimizing Torsion Angle Energies

Abstract Disclosure: D.R. Zak: None. E.C. Fink: None. G.R. Hancock: None. K.S. Young: None. S.W. Fanning: None. Overexpression of estrogen receptor alpha (ER-alpha) is found in 70% of breast cancer tumors. Normally, ER-alpha remains inactive and sequestered in the cytoplasm until estrogen binds to the ligand-binding domain (LBD) to enable nuclear translocation, coregulator recruitment, and subsequent activation of proliferative ER-alpha-dependent transcriptomic profiles. The majority of breast cancers are treated successfully with ER-targeted endocrine therapies, but hotspot ER-alpha LBD mutants are selected for, namely Y537S and D538G causing therapeutic resistance, relapse, and aggressive metastatic disease. The selective estrogen receptor modulator (SERM) lasofoxifene (laso) and selective estrogen receptor degrader (SERD) elacestrant (RAD1901) are chemically distinctive and show great promise in the ER-alpha mutant setting with potent anti-tumor effects and improved side effect profiles compared to the standard-of-care SERD fulvestrant (ICI). To elucidate the structural-transcriptional relationships of these ligands, we created a laso/RAD1901 chemical hybrid T6I-29 that demonstrated both canonical and unexpected therapeutic mechanisms of action. However, it possesses reduced anti-proliferative potency compared to ICI. We hypothesized that minor chemical changes to T6I-29 could improve potency while maintaining its favorable pharmaceutical profiles. To address this hypothesis, we performed quantum mechanical calculations of a series of T6I-derivatives. The addition of a methyl linker within the scaffold core significantly improved the torsion angle energies of the ligand binding pose. Multiple derivatives were synthesized based on these computations. The new compound T6I-B2 exerted profound anti-proliferative effects on breast cancer cells and adopted a unique ligand binding pose within the LBD. This approach shows that T6I-SERM potency can be improved by optimizing ligand torsion angle energies. Presentation: 6/3/2024

8523 An Unconventional Estrogen Receptor Conformation Induces SUMO Expression In Breast Cancer Cells

Abstract Disclosure: G.R. Hancock: None. K. Young: None. G.L. Greene: None. S.W. Fanning: None. An Unconventional Estrogen Receptor Conformation Induces SUMO Expression in Breast Cancer Cells Govinda Hancock, Kristen Young, Geoffrey L. Greene, Sean W. Fanning Competitive allosteric regulators, selective estrogen receptor modulators (SERMs)/degraders (SERDs) differentially manipulate receptor structure to treat and prevent metastatic breast cancers. However, their utility is limited by the ∼40% rate of disease progression due to acquired therapy resistance. In this study, a new SERM based on a tetrahydro-6-isoquinoline (T6I) scaffold reveals the relationship between ERα conformation and therapeutic transcriptional pathways in drug-resistant breast cancers. Optimization of structure-activity relationships produced unique lead compound that engages transcriptional programs similar to the clinically approved SERD fulvestrant. Notably, both drugs induce the expression of small ubiquitin-like modifier-1 (SUMO1), in opposition to the pathogenic hormone 17β-estradiol. SUMOylation is a post-translational modification affecting protein-protein interactions, localization, stability and functional properties. High expression of SUMO1 is associated with better patient prognosis in ERα+ disease. SUMOylation in breast cancer will be elucidated through understanding how it’s induced, its structural basis, and its role in therapeutic response of antiestrogen treatments. Presentation: 6/3/2024

7253 Changes In Bone Density Observed After Transitioning From Denosumab To Alendronate Or Zoledronic Acid

Abstract Disclosure: A. Khan: None. B.P. Ramchandani: None. R.A. Zielinski: None. J. Liu: None. F.S. Mirza: None. Introduction: Discontinuation of denosumab (Dmab) results in rebound increase in bone turnover and increased risk of vertebral fracture. Guidelines recommend that discontinuation of denosumab should be followed by an oral or intravenous bisphosphonate (BP), hormone therapy or selective estrogen receptor modulator (SERM). Hypothesis: We hypothesize that patients who received weekly alendronate (ALEN) after discontinuation of Dmab will have less of a decline in bone mineral density (BMD) compared to patients who received once yearly zoledronic acid (ZA). Methods: We conducted a retrospective chart review to compare the change in BMD and factors affecting BMD loss in patients who received sequential therapy with ZA versus ALEN. IRB approval was obtained. Patients were selected using Epic SlicerDicer if they had taken Dmab therapy from 2018 (year of epic implementation) onwards and had been transitioned to a BP. A total of 251 patients were initially selected. 35 patients met the inclusion criteria of being transitioned off to ALEN or ZA at least 1 year prior to date of data acquisition; 21 transitioned to ZA and 14 to ALEN. The rest of the patients were continuing Dmab and excluded from the analysis. BMD gain after Dmab therapy was evaluated. BMD change after 1 year of receiving sequential therapy was compared between the two groups at the lumbar spine (LS), femoral neck (FN), and total hip (TH). Results: A total of 35 patients were included in data analysis with mean age of 73.7 + 9 years. The mean percentage gain in BMD achieved after Dmab therapy was 9.9 + 8.5%, 4.6 + 10.6%, and 6 + 5.2% at the LS, FN and TH respectively. The mean duration of Dmab therapy was 4.4 + 2.1 years. One year following sequential therapy, mean percentage BMD loss at the LS was 4.5% with ALEN and 3.0% with ZA (p-value: 0.59, 95% CI: -0.04 to 0.08). Following sequential therapy, mean percentage loss at FN was 2.2% with ALEN and 0.2% with ZA (p-value: 0.1895% CI: (-0.01 to 0.04), mean percentage loss at TH was 2.0 % with ALEN and 2.2% with ZA (p-value: 0.78, 95% CI: -0.03 to 0.02). Mean vitamin D level of all patients at time of starting sequential therapy was 45.9 + 12.9 ng/ml. Duration of prior bisphosphonate use before starting Dmab therapy did not have any significant effect on BMD loss after sequential therapy. All patients had vitamin D level in a good range at the beginning and end of the study period. Conclusion: There is invariably some decline in BMD when transitioning from Dmab to BPs. Although our data showed somewhat greater BMD loss at LS and FN with ALEN compared to ZA, this difference was not statistically significant and failed to reject the null hypothesis. These findings need to be evaluated further in larger prospective studies. Presentation: 6/3/2024

7426 Tamoxifen-Induced Ovarian Hyperstimulation in a Pre-Menopausal Patient with Breast Cancer History: Spontaneous Resolution with Conservative Management

Abstract Disclosure: S. Gondi: None. M. Contento: None. A. Leiter: None. Background: Tamoxifen is a selective estrogen receptor modulator (SERM) that competitively binds to estrogen receptors (ER) on tumors and inhibits the effect of estrogen, which is used in the treatment and prevention of ER-positive breast cancer. Tamoxifen therapy has been reported to increase serum estrogens and cause ovarian hyperstimulation in premenopausal women, but knowledge on how to manage these conditions is limited. Clinical Case: A 36-year-old pre-menopausal female with history of malignant neoplasm of the right breast (ER positive) who completed neoadjuvant chemotherapy, lumpectomy, and radiation, on tamoxifen for seven years presented with new-onset oligomenorrhea. Laboratory testing done by the patient’s gynecologist revealed total estrogen 2,723 pg/mL (reference range [RR] 34-501), testosterone 132 ng/dL (RR 8-60), anti-Mullerian hormone 12.7 ng/mL (RR for age 0.66-8.75), ovulation-phase follicle stimulating hormone 11.5 mIU/mL (RR 4.7-21.5) and luteinizing hormone (LH) 63.3 mIU/mL (RR 14-95.6). Further workup revealed that ovarian tumor markers alpha-fetoprotein and serum human chorionic gonadotropin and other labs including dehydroepiandrosterone sulfate, progesterone 17-OH, lactate dehydrogenase, prolactin, and thyroid stimulating hormone were normal. Transvaginal ultrasound (TVUS) showed a new 2.8 x 1.9 x 2.3 cm complex left ovarian cyst, which, along with the elevated estrogen level, was concerning for ovarian hyperstimulation. Treatment with LH-releasing hormone (LHRH) agonists, surgical consultation, and discontinuation of tamoxifen were offered as potential management strategies, but the patient opted for observation and continued tamoxifen. Two months later, estradiol was 989 pg/mL (RR 85-498), and then three months later decreased to 152 pg/mL with repeat TVUS showing resolution of the left ovarian cyst. The patient’s oligomenorrhea resolved with resumption of regular menstrual cycles. Conclusion: While it is well-known that tamoxifen causes elevated serum estrogen levels and can lead to ovarian hyperstimulation, there is limited research on the management of these side effects. Treatment strategies in past cases have included oophorectomy or medical management with LHRH agonists or gonadotropin-RH agonists. However, this case demonstrates that a tamoxifen-induced ovarian cyst and high estrogen levels can resolve on its own with continued tamoxifen treatment. Conservative management with monitoring via imaging and repeat estrogen levels may be sufficient in management of pre-menopausal women with tamoxifen-induced ovarian hyperstimulation. Presentation: 6/1/2024

8464 A Unique SERM Reveals An Estrogen Receptor-Dependent Secretion Of DKK1 In Breast Cancer Cells

Abstract Disclosure: K.S. Young: None. G. Hancock: None. S. Kregel: None. S.W. Fanning: Grant Recipient; Self; Olema Oncology. Although Estrogen Receptor positive (ER+) breast cancer has been successfully targeted in primary tumors, the critical limitations of hormone therapies are ultimately revealed as many women often experience disease recurrence. A subset of these patients harbor a distinctive tyrosine to serine missense mutation at position 537 (Y537S) in ER leading to allele-specific transcriptional programs that enhance metastasis. ER is a ligand-dependent master transcriptional regulator. Probing unique ER structural features can reveal new transcriptional activities. We developed a structurally unconventional Selective Estrogen Receptor Modulator (SERM), T6I-29, to better understand these structure-transcriptional relationships. T6I-29 shows effective anti-tumoral activities in Y537S ESR1 breast cancer cells. To examine the anti-tumoral mechanism of T6I-29 action, we performed RNA-sequencing on ESR1 Y537S mutant breast cancer cells. Compared to other clinically relevant compounds, our drug uniquely and significantly downregulated DKK1, a tumor secreted protein known to modulate the Wnt/β-Catenin and PI3K/Akt pathways. Upregulation of DKK1 correlates with metastatic burden across multiple cancers but has not been evaluated in ESR1 mutant breast cancers. We find that DKK1 levels are significantly elevated in the plasma of 108 ER+ breast cancer patients compared to 100 matched healthy donors. Furthermore, in wild-type (WT) PIK3CA breast cancer cell lines, those with Y537S ESR1 mutation show constitutive expression and secretion of DKK1, while DKK1 expression and secretion is estrogen-dependent in WT breast cancer cells. Intriguingly, WT cells show significant surface bound DKK1, which is secreted into the media upon hormone stimulation and blocked by T6I-29. Understanding the ER-dependence and functional importance of DKK1 secretion offers a novel approach to potentially reduce breast cancer metastatic burden. Presentation: 6/3/2024

7250 Effects of Romosozumab According To Prior Anti-Resorptive Treatments In Korean Postmenopausal Women From The Real-World Data: A Multi-Center Retrospective Study

Abstract Disclosure: Y. Kim: None. S. Ahn: None. S. Lee: None. S. Lee: None. H. Kim: None. S. Hong: None. Objectives: This study investigated the effects of romosozumab in Korean postmenopausal women based on their prior anti-resorptive treatments for osteoporosis from real-world data. Methods: A retrospective analysis of 145 postmenopausal women (66 drug-naïve [45.5%], 27 prior bisphosphonate [BP, 18.6%], 11 prior selective estrogen receptor modulator [SERM, 7.6%], and 41 prior denosumab [DMAB, 28.3%] groups) who received a 12-month romosozumab treatment between March 2020 and June 2023 at four hospitals in Korea was conducted. Changes in bone mineral densities (BMDs) at the lumbar spine (LS), total hip (TH), and femoral neck (FN), as well as bone turnover markers (C-telopeptide [CTX] and N-terminal type I procollagen propeptide [P1NP]), were evaluated. Results: Significant differences in BMD changes at all skeletal sites were observed between the groups (LS, TH, and FN: P<0.001, P<0.001, and P=0.018, respectively). Especially, the drug-naïve group showed a significantly greater increase in BMD change than the prior DMAB group at LS (17.5% vs. 6.5%, P<0.001), TH (4.8% vs. -0.2%, P<0.001), and FN (5.7% vs. 1.4%, P=0.015). The highest levels of P1NP were observed in the drug-naïve, prior BP, and prior SERM groups after one month of romosozumab treatment, while it was observed after six months in the prior DMAB group. Additionally, CTX levels decreased in the drug-naïve, prior BP, and prior SERM groups during romosozumab treatment, while an increase was observed in the prior DMAB group. Conclusion: The efficacy of romosozumab treatment is influenced by prior anti-resorptive therapies. Further investigation is necessary to develop personalized strategies for optimizing romosozumab's effectiveness based on prior osteoporosis medications, especially in prior DMAB group. Presentation: 6/3/2024

Inhibition of neuroinflammation and neuronal damage by the selective non-steroidal ERβ agonist AC-186.

AC-186 (4-[4-4-Difluoro-1-(2-fluorophenyl) cyclohexyl] phenol) is a neuroprotective non-steroidal selective oestrogen receptor modulator. This study investigated whether inhibition of neuroinflammation contributed to neuroprotective activity of this compound. BV-2 microglia were treated with AC-186 (0.65-5 μM) prior to stimulation with LPS(100 ng/mL). Levels of pro-inflammatory mediators and proteins were then evaluated. Treatment of LPS-activated BV-2 microglia with AC-186 resulted in significant (p < 0.05) reduction in TNFα, IL-6, NO, PGE2, iNOS and COX-2. Further investigations showed that AC-186 decreased LPS-induced elevated levels of phospho-p65, phospho-IκBα and acetyl-p65 proteins, while blocking DNA binding and luciferase activity of NF-κB. AC-186 induced significant (p < 0.05) increase in protein expression of ERβ, while enhancing ERE luciferase activity in BV-2 cells. Effects of the compound on oestrogen signalling in the microglia was confirmed in knockdown experiments which revealed a loss of anti-inflammatory activity following transfection with ERβ siRNA. In vitro neuroprotective activity of AC-186 was demonstrated by inhibition of activated microglia-mediated damage to HT-22 neurons. This study established that AC-186 produces NF-κB-mediated anti-inflammatory activity, which is proposed as a contributory mechanism involved in its neuroprotective actions. It is suggested that the anti-inflammatory activity of this compound is linked to its agonist effect on ERβ.

Raloxifene Prevents Chemically-Induced Ferroptotic Neuronal Death In Vitro and In Vivo.

Ferroptosis, a regulated form of cell death characterized by excessive iron-dependent lipid peroxidation, can be readily induced in cultured cells by chemicals such as erastin and RSL3. Protein disulfide isomerase (PDI) has been identified as an upstream mediator of chemically induced ferroptosis and also a target for ferroptosis protection. In this study, we discovered that raloxifene (RAL), a selective estrogen receptor modulator known for its neuroprotective actions in humans, can effectively inhibit PDI function and provide robust protection against chemically induced ferroptosis in cultured HT22 neuronal cells. Specifically, RAL can bind directly to PDI both in vitro and in intact neuronal cells and inhibit its catalytic activity. Computational modeling analysis reveals that RAL can tightly bind to PDI through forming a hydrogen bond with its His256 residue, and biochemical analysis further shows that when PDI's His256 is mutated to Ala256, RAL loses its inhibition of PDI's catalytic activity. This inhibition of PDI by RAL significantly reduces the dimerization of both the inducible and neuronal nitric oxide synthases and the accumulation of nitric oxide, both of which have recently been shown to play a crucial role in mediating chemically induced ferroptosis through subsequent induction of ROS and lipid-ROS accumulation. In vivo behavioral analysis shows that mice treated with RAL are strongly protected against kainic acid-induced memory deficits and hippocampal neuronal damage. In conclusion, this study demonstrates that RAL is a potent inhibitor of PDI and can effectively prevent chemically induced ferroptosis in hippocampal neurons both in vitro and in vivo. These findings offer a novel estrogen receptor-independent mechanism for RAL's neuroprotective actions in animal models and humans.

Clinical Pharmacology Of Selective Oestrogen Receptor Modulators In The Prevention Of Breast Cancer, Osteoporosis, Coronary Heart Disease, Alzheimer's Disease, Use In Hormone Replacement Therapy, Cholesterol Metabolism

Oestrogen is the key regulatory hormone for the development and maintenance of reproductive functions and affects various physiological systems, including the skeletal, cardiovascular, and central nervous systems. oestrogen replacement therapy (ERT) is highly effective in postmenopausal women, addressing menopausal symptoms and providing beneficial effects on osteoporosis and coronary heart disease. However, ERT is associated with significant side effects, such as an increased risk of breast cancer. To mitigate these risks, selective oestrogen receptor modulators (SERMs) have been developed. SERMs are a growing class of synthetic nonsteroidal compounds that act as oestrogen receptor agonists or antagonists in a tissue-specific manner. They can selectively activate or inhibit oestrogen receptors in different tissues throughout the body. SERMs are used to treat a variety of conditions, including ER-positive breast cancer, osteoporosis, coronary heart disease, Alzheimer’s disease, and cholesterol metabolism disorders in postmenopausal women. Specific SERMs are employed for different conditions: raloxifene for osteoporosis, tamoxifen and toremifene for breast cancer, clomiphene for the induction of ovulation, and ormeloxifene for oral contraception. Arzoxifene is used for altering cholesterol metabolism. Each SERM forms a unique complex with oestrogen receptors, influencing target tissues and resulting in a tissue-selective pharmacological profile. This unique mechanism of action translates into specific safety and efficacy profiles for each SERM. The surprising pharmacology of SERMs has sparked interest in developing new selective medications, allowing for precise treatment of various diseases. This article reviews the pharmacological properties of SERMs and explains how they differ from oestrogen in their actions.

TEMPORARY REMOVAL: Effect of soy isoflavones on measures of estrogenicity: A systematic review and meta-analysis of randomized controlled trials

BackgroundDespite recommendations to increase plant food consumption for public and planetary health and the role that soy foods can play in plant-predominant diets, controversies around the effects of soy foods and especially soy isoflavones, are a barrier to their intake. Given their cardioprotective effects and ability to alleviate menopausal symptoms, addressing these concerns is particularly relevant to women. ObjectiveThis systematic review and meta-analysis of randomized controlled trials aimed to determine the effect of soy isoflavones on measures of estrogenicity in postmenopausal women. MethodsMEDLINE, Embase, and Cochrane Library were searched through August 2024 for randomized trials 3-months investigating soy isoflavones versus non-isoflavone controls in postmenopausal women. Outcomes included endometrial thickness (ET), vaginal maturation index (VMI), follicle-stimulating hormone (FSH), and estradiol. Independent authors extracted data and assessed risk of bias. GRADE (grading of recommendations assessment, development, and evaluation) was used to assess certainty of evidence. ResultsWe included 40 trials (52 trial comparisons, n=3285) assessing the effect of a median reported dose of 75mg/day of soy isoflavones in substitution for non-isoflavone controls over a median of 24 weeks. Soy isoflavones had no statistically significant effect on any measure of estrogenicity; ET (mean difference, -0.22mm [95% confidence interval, -0.45, 0.01mm], PMD=0.059), VMI (2.31 [-2.14, 6.75], PMD=0.310), FSH (-0.02IU/L [-2.39, 2.35IU/L], PMD=0.987), and estradiol (1.61pmol/L [-1.17, 4.38pmol/L], PMD=0.256). The certainty of evidence was high-to-moderate for all outcomes. ConclusionsCurrent evidence suggests that soy isoflavones do not exhibit estrogenic effects compared to non-isoflavone controls on 4 measures of estrogenicity in postmenopausal women. This synthesis supports that soy isoflavones likely act as selective estrogen receptor modulators, differing clinically from the hormone estrogen. Addressing public health concerns may promote soy foods as high-quality plant protein sources with low environmental impact and cost, particularly benefiting postmenopausal women, and aligning with sustainable dietary patterns and guidelines. RegistrationPROSPERO (CRD42023439239)

Severe carbohydrate restriction augments the antiproliferative effect of hormonal therapy in a murine model of Ehrlich breast adenocarcinoma: histological and immunohistochemical investigations

BackgroundMalignant tumors of the breast are the most diagnosed cancers in females globally. Recent evidence suggests that carbohydrate restriction (CR), especially ketogenic diets, has become a potential treatment approach for many malignancies, including breast cancer. Tamoxifen (TAX) is a selective estrogen receptor modulator (ERM) that can reduce the risk of cancer recurrence. The current work was designed to assess the impact of CR on the proliferation of breast adenocarcinoma cells and to compare this impact with that of TAX. Study groups included: group 1: vehicle-treated mice; group 2: the Ehrlich group: injected Ehrlich ascites carcinoma (EAC) cells (2.5 × 106) in 0.25 ml isotonic saline; group 3: CR group: mice were supplied with a diet regimen of severe CR throughout the study and injected EAC at week 7; group 4: hormonal therapy (HT) group: mice in this group injected with EAC at week 7 and then received TAX at a dose of 20 mg/kg 3 times/week orally for 3 weeks; and lastly group 5: the group of combined intervention. The mice in the CR, HT, and the combined groups received Ehrlich cancer cells at the same dose and route as the Ehrlich group.ResultsCR and HT groups demonstrated a significant decrease in levels of insulin-like growth factor (IGF-1), carbohydrate antigen (CA 15–3), hexokinase 2 (HK2), hypoxia-inducible factor-1 (HIF-1) α, and malondialdehyde (MDA) compared to the Ehrlich group. Additionally, the mean area % of caspase-3 was significantly increased, and the mean area % of Ki67 and estrogen receptor (ER)α was significantly decreased.ConclusionsThe combined treatment demonstrated the most advantageous outcome, as evidenced by reduced CA 15–3 levels, tumor size, and the mean area % of Ki67. This suggests that the addition of severe CR to the conventional therapy of breast cancer has a beneficial effect.

The sexually dimorphic expression of glutamate transporters and their implication in pain after spinal cord injury.

In addition to the loss of motor function, ~60% of patients develop pain after spinal cord injury. The cellular-molecular mechanisms are not well understood, but the data suggests that plasticity within the rostral, epicenter, and caudal penumbra of the injury site initiates a cellular-molecular interplay that acts as a rewiring mechanism leading to central neuropathic pain. Sprouting can lead to the formation of new connections triggering abnormal sensory transmission. The excitatory glutamate transporters are responsible for the reuptake of extracellular glutamate which makes them a critical target to prevent neuronal hyperexcitability and excitotoxicity. Our previous studies showed a sexually dimorphic therapeutic window for spinal cord injury after treatment with the selective estrogen receptor modulator tamoxifen. In this study, we investigated the anti-allodynic effects of tamoxifen in male and female rats with spinal cord injury. We hypothesized that tamoxifen exerts anti-allodynic effects by increasing the expression of glutamate transporters, leading to reduced hyperexcitability of the secondary neuron or by decreasing aberrant sprouting. Male and female rats received a moderate contusion to the thoracic spinal cord followed by subcutaneous slow-release treatment of tamoxifen or matrix pellets as a control (placebo). We used von Frey monofilaments and the "up-down method" to evaluate mechanical allodynia. Tamoxifen treatment decreased allodynia only in female rats with spinal cord injury revealing a sex-dependent effect. The expression profile of glutamatergic transporters (excitatory amino acid transporter 1/glutamate aspartate transporter and excitatory amino acid transporter 2/glutamate transporter-1) revealed a sexual dimorphism in the rostral, epicenter, and caudal areas of the spinal cord with a pattern of expression primarily on astrocytes. Female rodents showed a significantly higher level of excitatory amino acid transporter-1 expression while male rodents showed increased excitatory amino acid transporter-2 expression compared with female rodents. Analyses of peptidergic (calcitonin gene-related peptide-α) and non-peptidergic (isolectin B4) fibers outgrowth in the dorsal horn after spinal cord injury showed an increased calcitonin gene-related peptide-α/ isolectin B4 ratio in comparison with sham, suggesting increased receptive fields in the dorsal horn. Although the behavioral assay shows decreased allodynia in tamoxifen-treated female rats, this was not associated with overexpression of glutamate transporters or alterations in the dorsal horn laminae fibers at 28 days post-injury. Our findings provide new evidence of the sexually dimorphic expression of glutamate transporters in the spinal cord. The dimorphic expression revealed in this study provides a therapeutic opportunity for treating chronic pain, an area with a critical need for treatment.