Update on raloxifene: mechanism of action, clinical efficacy, adverse effects, and contraindications

Synthesis Studies and the Evaluation of C6 Raloxifene Derivatives

Methodology is described for the synthesis of C6 derivatives of raloxifene, a prescribed drug for the treatment and prevention of osteoporosis. Studies have explored the incorporation of electron-withdrawing substituents at C6 of the benzothiophene core. Efficient processes are also examined to introduce hydrogen bond donor and acceptor functionality. Raloxifene derivatives are evaluated with in vitro testing to determine estrogen receptor (ER) binding affinity and gene expression in MC3T3 cells.

Impact of in vitro SARS-CoV-2 infection on breast cancer cells

The pandemic of coronavirus disease 19 (COVID-19), caused by severe respiratory syndrome coronavirus 2 (SARS-CoV-2), had severe repercussions for breast cancer patients. Increasing evidence indicates that SARS-CoV-2 infection may directly impact breast cancer biology, but the effects of SARS-CoV-2 on breast tumor cells are still unknown. Here, we analyzed the molecular events occurring in the MCF7, MDA-MB-231 and HCC1937 breast cancer cell lines, representative of the luminal A, basal B/claudin-low and basal A subtypes, respectively, upon SARS-CoV-2 infection. Viral replication was monitored over time, and gene expression profiling was conducted. We found that MCF7 cells were the most permissive to viral replication. Treatment of MCF7 cells with Tamoxifen reduced the SARS-CoV-2 replication rate, suggesting an involvement of the estrogen receptor in sustaining virus replication in malignant cells. Interestingly, a metagene signature based on genes upregulated by SARS-CoV-2 infection in all three cell lines distinguished a subgroup of premenopausal luminal A breast cancer patients with a poor prognosis. As SARS-CoV-2 still spreads among the population, it is essential to understand the impact of SARS-CoV-2 infection on breast cancer, particularly in premenopausal patients diagnosed with the luminal A subtype, and to assess the long-term impact of COVID-19 on breast cancer outcomes.

Development and validation of CYP26A1 inhibition assay for high-throughput screening

All-trans retinoic acid (atRA) is an endogenous ligand of the retinoic acid receptors, which heterodimerize with retinoid X receptors. AtRA is generated in tissues from vitamin A (retinol) metabolism to form a paracrine signal and is locally degraded by cytochrome P450 family 26 (CYP26) enzymes. The CYP26 family consists of three subtypes: A1, B1, and C1, which are differentially expressed during development. This study aims to develop and validate a high throughput screening assay to identify CYP26A1 inhibitors in a cell-free system using a luminescent P450-Glo assay technology. The assay performed well with a signal to background ratio of 25.7, a coefficient of variation of 8.9%, and a Z-factor of 0.7. To validate the assay, we tested a subset of 39 compounds that included known CYP26 inhibitors and retinoids, as well as positive and negative control compounds selected from the literature and/or the ToxCast/Tox21 portfolio. Known CYP26A1 inhibitors were confirmed, and predicted CYP26A1 inhibitors, such as chlorothalonil, prochloraz, and SSR126768, were identified, demonstrating the reliability and robustness of the assay. Given the general importance of atRA as a morphogenetic signal and the localized expression of Cyp26a1 in embryonic tissues, a validated CYP26A1 assay has important implications for evaluating the potential developmental toxicity of chemicals.

Research Progress on the Mechanism of the SFRP-Mediated Wnt Signalling Pathway Involved in Bone Metabolism in Osteoporosis

Osteoporosis (OP) is a metabolic bone disease linked to an elevated fracture risk, primarily stemming from disruptions in bone metabolism. Present clinical treatments for OP merely alleviate symptoms. Hence, there exists a pressing need to identify novel targets for the clinical treatment of OP. Research indicates that the Wnt signalling pathway is modulated by serum-secreted frizzled-related protein 5 (SFRP5), potentially serving as a pivotal regulator in bone metabolism disorders. Moreover, studies confirm elevated SFRP5 expression in OP, with SFRP5 overexpression leading to the downregulation of Wnt and β-catenin proteins in the Wnt signalling pathway, as well as the expression of osteogenesis-related marker molecules such as RUNX2, ALP, and OPN. Conversely, the opposite has been reported when SFRP5 is knocked out, suggesting that SFRP5 may be a key factor involved in the regulation of bone metabolism via the Wnt signalling axis. However, the molecular mechanisms underlying the action of SFRP5-induced OP have yet to be comprehensively elucidated. This review focusses on the molecular structure and function of SFRP5 and the potential molecular mechanisms of the SFRP5-mediated Wnt signalling pathway involved in bone metabolism in OP, providing reasonable evidence for the targeted therapy of SFRP5 for the prevention and treatment of OP.

Exploring the nexus of nuclear receptors in hematological malignancies

Hematological malignancies (HM) represent a subset of neoplasms affecting the blood, bone marrow, and lymphatic systems, categorized primarily into leukemia, lymphoma, and multiple myeloma. Their prognosis varies considerably, with a frequent risk of relapse despite ongoing treatments. While contemporary therapeutic strategies have extended overall patient survival, they do not offer cures for advanced stages and often lead to challenges such as acquisition of drug resistance, recurrence, and severe side effects. The need for innovative therapeutic targets is vital to elevate both survival rates and patients' quality of life. Recent research has pivoted towards nuclear receptors (NRs) due to their role in modulating tumor cell characteristics including uncontrolled proliferation, differentiation, apoptosis evasion, invasion and migration. Existing evidence emphasizes NRs' critical role in HM. The regulation of NR expression through agonists, antagonists, or selective modulators, contingent upon their levels, offers promising clinical implications in HM management. Moreover, several anticancer agents targeting NRs have been approved by the Food and Drug Administration (FDA). This review highlights the integral function of NRs in HM's pathophysiology and the potential benefits of therapeutically targeting these receptors, suggesting a prospective avenue for more efficient therapeutic interventions against HM.

Hemostatic Effects of Raloxifene in Ovariectomized Rats

This study aimed to explore the effects of raloxifene (Rx) and estradiol (E₂) on prothrombin time (PT), partial thromboplastin time (APTT), coagulation factors (VII, X, XI), and fibrinogen concentrations in rats. Female rats were ovariectomized 11 days prior to starting the treatment. Afterward, they received Rx or E₂ (1, 10, 100, and 1000 µg/kg) or propylene glycol (0.3 mL; vehicle, V) subcutaneously for 3 consecutive days. Plasma was collected to measure the hemostatic parameters. Rx significantly increased PT (8%, at 1000 µg/kg; p < 0.05) and APTT at all doses evaluated (32, 70, 67, 30%; p < 0.05, respectively). Rx (1, 10, 100, and 1000 µg/kg) decreased the activity of factor VII by -20, -40, -37, and -17% (p < 0.05), respectively, and E₂ increased it by 9, 34, 52, and 29%. Rx reduced factor X activity at 10 and 100 µg/kg doses (-30, and -30% p < 0.05), and E₂ showed an increment of 24% with 1000 µg/kg dose only. Additionally, Rx (1, 10, 100 µg/kg) diminished FXI activity (-71, -62, -66; p < 0.05), E₂ (1 and 10 µg/kg) in -60 and -38, respectively (p < 0.05), and Rx (1000 µg/kg) produced an increment of 29% (p < 0.05) in fibrinogen concentration, but not E₂. Our findings suggest that raloxifene has a protective effect on hemostasis in rats.

How Has Molecular Biology Enhanced Our Undertaking of axSpA and Its Management

PURPOSE

This review aims at investigating pathophysiological mechanisms in spondyloarthritis (SpA). Analysis of genetic factors, immunological pathways, and abnormalities of bone metabolism lay the foundations for a better understanding of development of the axial clinical manifestations in patients, allowing physician to choose the most appropriate therapeutic strategy in a more targeted manner.

RECENT FINDINGS

In addition to the contribution of MHC system, findings emerged about the role of non-HLA genes (as ERAP1 and 2, whose inhibition could represent a new therapeutic approach) and of epigenetic mechanisms that regulate the expression of genes involved in SpA pathogenesis. Increasing evidence of bone metabolism abnormalities secondary to the activation of immunological pathways suggests the development of various bone anomalies that are present in axSpA patients. SpA are a group of inflammatory diseases with a multifactorial origin, whose pathogenesis is linked to the genetic predisposition, the action of environmental risk factors, and the activation of immune response. It is now well known how bone metabolism leads to long-term structural damage via increased bone turnover, bone loss and osteoporosis, osteitis, erosions, osteosclerosis, and osteoproliferation. These effects can exist in the same patient over time or even simultaneously. Evidence suggests a cross relationship among innate immunity, autoimmunity, and bone remodeling in SpA, making treatment approach a challenge for rheumatologists. Specifically, treatment targets are consistently increasing as new drugs are upcoming. Both biological and targeted synthetic drugs are promising in terms of their efficacy and safety profile in patients affected by SpA.

Mitophagy Induction and Aryl Hydrocarbon Receptor-Mediated Redox Signaling Contribute to the Suppression of Breast Cancer Cell Growth by Taloxifene via Regulation of Inflammasomes Activation

Aims: Raloxifene, a selective estrogen receptor (ER) modulator, has been reported to exert the tumor-suppressive effects in both ER-positive and ER-negative cancer cells; however, the mechanisms underlying its ER-independent anti-cancer effects are poorly understood. The NLRP3 inflammasome, a critical component of the innate immune system, has recently received growing attention owing to its multifaceted roles in various aspects of cancer development. The present study aimed at examining the involvement of NLRP3 inflammasomes in the anti-breast cancer effects of raloxifene and its underlying mechanisms. Results: Raloxifene significantly inhibited the activation of NLRP3 inflammasomes in various breast cancer cell lines. Importantly, forced expression of a gain-of-function variant of NLRP3 rescued breast cancer cells from growth arrest by raloxifene, suggesting that the suppression of NLRP3 inflammasomes activation mediates the raloxifene-induced inhibition of breast cancer growth. Mechanistically, raloxifene suppressed NLRP3 inflammasomes activation by lowering the cellular levels of reactive oxygen species (ROS) through the modulation of redox signaling mediated via aryl hydrocarbon receptor (AhR)-nuclear factor erythroid 2-related factor 2 (Nrf2)-heme oxygenase-1 (HO-1) axis or the impaired generation of mitochondrial ROS in a mitophagy-dependent manner. Further, the blockage of AhR signaling or inhibition of mitophagy abolished the tumor-suppressive effect of raloxifene in a human breast tumor xenograft model. Innovation: We elucidate a novel molecular mechanism underlying the breast tumor suppressing effect of raloxifene. Conclusion: The results observed in this study suggest that the modulation of NLRP3 inflammasomes activation is a critical event in the inhibition of breast tumor growth by raloxifene. Antioxid. Redox Signal. 37, 1030-1050.

The Regulatory Role of Lipid Metabolism in Endometrial Cancer

Endometrial cancer is the 6th most common carcinoma as well as the 2nd most common malignancy worldwide in women. It is closely related to fat content, and dyslipidemia is among the most significant metabolic changes in this cancer. Therefore, further understanding of the regulation mechanism in lipid metabolism of endometrial cancer is conducive to the development of better therapeutic strategies and methods. Here, we systematically review the signaling pathways that regulate lipid metabolism in endometrial cancer and the research progress of drugs and targeted therapies that act on lipid metabolism by retrieving relevant articles. The underlying mechanism of occurrence and development of endometrial cancer is relatively clear and comprehensively reviewed here. But following more research studies will help to illuminate more specific regulatory roles of lipid metabolism in endometrial cancer and explore new possible mechanisms, prognostic and therapeutic targets, and subsequent drugs. Our review will provide a full view for the following investigation of lipid metabolism in endometrial cancer.

To clot, or not to clot: The dilemma of hormone treatment options for menopause

Untreated menopause may have serious health implications, but treatments can have dangerous side effects. We evaluate menopausal symptoms as well as available treatments -the routes of administration and their effect on blood coagulation. Menopausal females may experience hot flushes, vulva- and vaginal atrophy and osteoporosis. Many treatments are available to relieve these symptoms such as Conjugated Equine Estrogen and bioidentical hormones. The routes of administration include oral and transdermal. Hormones that are administered orally undergo a hepatic first pass metabolism. The by-products have a lower efficacy and possibly enhanced side effects. Furthermore, hormone treatments influence the coagulation cascade through coagulation factors or their regulators. Increased coagulation poses a risk for venous thromboembolism. Currently a definite conclusion on whether the side effects from hormone treatments exceed the risk of untreated menopause cannot be made. However, a more individualised approach to hormone treatments may be the most feasible solution to this dilemma.

Nuclear receptor RORγ inverse agonists/antagonists display tissue- and gene-context selectivity through distinct activities in altering chromatin accessibility and master regulator SREBP2 occupancy

The nuclear receptor RORγ is a major driver of autoimmune diseases and certain types of cancer due to its aberrant function in T helper 17 (Th17) cell differentiation and tumor cholesterol metabolism, respectively. Compound screening using the classic receptor-coactivator interaction perturbation scheme led to identification of many small-molecule modulators of RORγ(t). We report here that inverse agonists/antagonists of RORγ such as VTP-43742 derivative VTP-23 and TAK828F, which can potently inhibit the inflammatory gene program in Th17 cells, unexpectedly lack high potency in inhibiting the growth of TNBC tumor cells. In contrast, antagonists such as XY018 and GSK805 that strongly suppress tumor cell growth and survival display only modest activities in reducing Th17-related cytokine expression. Unexpectedly, we found that VTP-23 significantly induces the cholesterol biosynthesis program in TNBC cells. Our further mechanistic analyses revealed that VTP-23 enhances the local chromatin accessibility, H3K27ac mark and the cholesterol master regulator SREBP2 recruitment at the RORγ binding sites, whereas XY018 exerts the opposite activities. Yet, they display similar inhibitory effects on circadian rhythm program. Similar distinctions and contrasting activities between TAK828F and SR2211 in their effects on local chromatin structure at Il17 genes were also observed. Together, our study shows for the first-time that structurally distinct RORγ antagonists possess different or even contrasting activities in tissue/cell-specific manner. Our findings also highlight that the activities at natural chromatin are key determinants of RORγ modulators' tissue selectivity.

Effects of Raloxifene and tibial loading on bone mass and mechanics in male and female mice

Purpose: Raloxifene (RAL) is a selective estrogen receptor modulator (SERM) that has previously been shown to cause acellular benefits to bone tissue. Due to these improvements, RAL was combined with targeted tibial loading to assess if RAL treatment during periods of active bone formation would allow for further mechanical enhancements.Methods: Structural, mechanical, and microstructural effects were assessed in bone from C57BL/6 mice that were treated with RAL (0.5 mg/kg), tibial loading, or both for 6 weeks, beginning at 10 weeks of age.Results:Ex vivo microcomputed tomography (CT) images indicated RAL and loading work together to improve bone mass and architecture, especially within the cancellous region of males. Increases in cancellous bone volume fraction were heavily driven by increases in trabecular thickness, though there were some effects on trabecular spacing and number. In the cortical regions, RAL and loading both increased cross-sectional area, cortical area, and cortical thickness. Whole-bone mechanical testing primarily indicated the effects of loading. Further characterization through Raman spectroscopy and nanoindentation showed load-based changes in mineralization and micromechanics, while both loading and RAL caused changes in the secondary collagen structure. In contrast to males, in females, there were large load-based effects in the cancellous and cortical regions, resulting in increased whole-bone mechanical properties. RAL had less of an effect on cancellous and cortical architecture, though some effects were still present.Conclusion: RAL and loading work together to impact bone architecture and mechanical integrity, leading to greater improvements than either treatment individually.

Identifying FAAH Inhibitors as New Therapeutic Options for the Treatment of Chronic Pain through Drug Repurposing

Chronic pain determines a substantial burden on individuals, employers, healthcare systems, and society. Most of the affected patients report dissatisfaction with currently available treatments. There are only a few and poor therapeutic options-some therapeutic agents are an outgrowth of drugs targeting acute pain, while others have several serious side effects. One of the primary degradative enzymes for endocannabinoids, fatty acid amide hydrolase (FAAH) attracted attention as a significant molecular target for developing new therapies for neuropsychiatric and neurological diseases, including chronic pain. Using chemical graph mining, quantitative structure-activity relationship (QSAR) modeling, and molecular docking techniques we developed a multi-step screening protocol to identify repurposable drugs as FAAH inhibitors. After screening the DrugBank database using our protocol, 273 structures were selected, with five already approved drugs, montelukast, repaglinide, revefenacin, raloxifene, and buclizine emerging as the most promising repurposable agents for treating chronic pain. Molecular docking studies indicated that the selected compounds interact with the enzyme mostly non-covalently (except for revefenacin) through shape complementarity to the large substrate-binding pocket in the active site. A molecular dynamics simulation was employed for montelukast and revealed stable interactions with the enzyme. The biological activity of the selected compounds should be further confirmed by employing in vitro and in vivo studies.

The Effects of Osteoporotic and Non-osteoporotic Medications on Fracture Risk and Bone Mineral Density

Osteoporosis is a highly prevalent bone disease affecting more than 37.5 million individuals in the European Union (EU) and the  United States of America (USA). It is characterized by low bone mineral density (BMD), impaired bone quality, and loss of structural and biomechanical properties, resulting in reduced bone strength. An increase in morbidity and mortality is seen in patients with osteoporosis, caused by the approximately 3.5 million new osteoporotic fractures occurring every year in the EU. Currently, different medications are available for the treatment of osteoporosis, including anti-resorptive and osteoanabolic medications. Bisphosphonates, which belong to the anti-resorptive medications, are the standard treatment for osteoporosis based on their positive effects on bone, long-term experience, and low costs. However, not only medications used for the treatment of osteoporosis can affect bone: several other medications are suggested to have an effect on bone as well, especially on fracture risk and BMD. Knowledge about the positive and negative effects of different medications on both fracture risk and BMD is important, as it can contribute to an improvement in osteoporosis prevention and treatment in general, and, even more importantly, to the individual's health. In this review, we therefore discuss the effects of both osteoporotic and non-osteoporotic medications on fracture risk and BMD. In addition, we discuss the underlying mechanisms of action.

Effects of raloxifene administration on serum levels of insulin-like growth factor-1 and insulin-like growth factor-binding protein 3 levels: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To ascertain the clinical magnitude of raloxifene administration on insulin-like growth factor-1 (IGF-1) and insulin-like growth factor-binding protein 3 (IGFBP-3) levels.

METHODS

A systematic comprehensive search was performed without language limitation up to 14 December 2020. We included only trials that assessed the effect of raloxifene on IGF-1 and IGFBP-3 in adults. Meta-analysis was performed using the Stata software (Stata Corp. College Station, Texas, USA).

RESULTS

Seven arms were included, encompassing postmenopausal women with type 2 diabetes mellitus, postmenopausal women with breast cancer, healthy postmenopausal women, and healthy elderly men. Raloxifene therapy significantly reduced IGF-1 levels (WMD: -2.92 nmol/L, 95% CI: -3.49, -2.35, p < 0.001) compared to placebo. Raloxifene dosage ˃60 mg/day (WMD: -3.29 ng/mL, 95% CI: -3.50 to -3.08, I² = 0.0%) decreased IGF-1 levels more than 60 mg/day (WMD: -2.29 ng/mL, 95% CI: -2.90 to -1.69, I² = 16%). Moreover, intervention duration ˃26 weeks (WMD: -3.48 ng/mL, 95% CI: -5.26 to -1.69, I² = 0.0%) reduced IGF-1 levels more than ˂26 weeks (WMD: -2.55 ng/mL, 95% CI: -3.31 to -1.79, I² = 92%). In contrast, overall results from the random-effects model did not suggest a significant change in IGFBP-3 levels upon raloxifene therapy.

CONCLUSION

Raloxifene therapy significantly reduced serum levels of IGF-1 levels but without changes in IGFPB-3 levels.

Targeting steroid hormone receptors for anti-cancer therapy-A review on small molecules and nanotherapeutic approaches

The steroid hormone receptors (SHRs) among nuclear hormone receptors (NHRs) are steroid ligand-dependent transcription factors that play important roles in the regulation of transcription of genes promoted via hormone responsive elements in our genome. Aberrant expression patterns and context-specific regulation of these receptors in cancer, have been routinely reported by multiple research groups. These gave an window of opportunity to target those receptors in the context of developing novel, targeted anticancer therapeutics. Besides the development of a plethora of SHR-targeting synthetic ligands and the availability of their natural, hormonal ligands, development of many SHR-targeted, anticancer nano-delivery systems and theranostics, especially based on small molecules, have been reported. It is intriguing to realize that these cytoplasmic receptors have become a hot target for cancer selective delivery. This is in spite of the fact that these receptors do not fall in the category of conventional, targetable cell surface bound or transmembrane receptors that enjoy over-expression status. Glucocorticoid receptor (GR) is one such exciting SHR that in spite of it being expressed ubiquitously in all cells, we discovered it to behave differently in cancer cells, thus making it a truly druggable target for treating cancer. This review selectively accumulates the knowledge generated in the field of SHR-targeting as a major focus for cancer treatment with various anticancer small molecules and nanotherapeutics on progesterone receptor, mineralocorticoid receptor, and androgen receptor while selectively emphasizing on GR and estrogen receptor. This review also briefly highlights lipid-modification strategy to convert ligands into SHR-targeted cancer nanotherapeutics. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Biology-Inspired Nanomaterials > Lipid-Based Structures Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Special Considerations to Improve Clinical Outcomes in Patients with Osteoporosis Undergoing Spine Surgery

BACKGROUND

Osteoporosis is a condition that is commonly encountered, with increasing diagnosis by the medical community with the aging population. Osteoporosis leaves patients susceptible to fragility fractures in the vertebrae and is also associated with degenerative changes, both of which may require intervention from a spine surgeon. The goal of this review is to concisely outline special nonoperative adjuncts, as well as preoperative, intraoperative, and postoperative considerations of osteoporotic patients undergoing spine intervention.

METHODS

A literature analysis was completed for this narrative review. A database search of PubMed and Google Scholar was conducted using "osteoporosis" combined with "spine," "spine surgery," and "spinal fusion" without exclusion based on publication date. Articles were screened to exclude duplicate articles and screened for their full text and English language availability.

RESULTS

The database search yielded recent publications from which the narrative review was completed.

CONCLUSIONS

Preoperatively, screening is traditionally completed with dual-energy x-ray absorptiometry (DEXA). Pharmacological therapy modalities currently include teriparatide, raloxifene, denosumab, bisphosphonates, and calcitonin. In order to prevent operative complications associated with osteoporosis, surgeons have found success in increasing the diameter and the length of pedicle screws, limiting pedicle tapping, achieving bicortical or even tricortical purchase, augmenting with polymethyl methacrylate, using iliosacral stabilization, preventing positive sagittal balance, and using adequate fusion products when necessary. Postoperatively, it is important to implant a care plan that includes adequate pain control and necessary care, and to understand risks associated with falls may increase risk of postoperative fragility fractures as well as instrumentation displacement. At this time there are no recommendations in regard to bracing in the postoperative setting.

CLINICAL RELEVANCE

This review article outlines the most current evidence-based medicine with regard to considerations in spine surgery of the osteoporotic patient, and aims to bring about new questions to be investigated in that paradigm.

Effects of Raloxifene Combined with Low-dose Conjugated Estrogen on the Endometrium in Menopausal Women at High Risk for Breast Cancer

OBJECTIVES

To compare the effects of low-dose conjugated estrogen (CE), raloxifene, and the combination thereof on the endometrium of postmenopausal women.

METHODS

Postmenopausal women between 45 and 60 years of age, with Gail score≥1.67 and no endometrial disorders, were randomly assigned to receive low-dose CE (0.3 mg), raloxifene (60 mg), or combined therapy for 1 year. Transvaginal ultrasound was performed at baseline and every 3 months; the Kupperman Index was assessed at baseline and every 6 months. Endometrial biopsies were performed if endometrial thickness (ET) was ≥5 mm or if vaginal bleeding occurred. The primary outcome was the occurrence of ET≥5 mm over the one-year period.

RESULTS

Seventy-three women were randomly assigned and analyzed on an intent-to-treat basis. Eight, three, and four women in the CE, raloxifene, and combination groups, respectively, exhibited ET≥5 mm. No genital bleeding was reported in the combination group. Endometrial biopsy revealed atrophy or polyps in all groups, with one patient in the CE group exhibiting a proliferative endometrium without atypia. At 6 months, there was a progressive increase in mean ET in the CE group, but not in the other two groups, with statistically significant differences at 6, 9, and 12 months. Mean scores for vasomotor symptoms and Kupperman Index favored the CE and combination groups over raloxifene.

CONCLUSION

Combined raloxifene and low-dose CE decreased the severity of menopausal symptoms to a similar extent as CE alone and had similar effects as raloxifene alone on the endometrium.

Development and validation of ultra-high-performance liquid chromatography-mass spectrometry method for the determination of raloxifene and its phase II metabolites in plasma: Application to pharmacokinetic studies in rats

The aim of this study is to establish a reliable liquid chromatography-mass spectrometry method to simultaneously quantitate raloxifene, and its major metabolites, raloxifene-6-glucuronide, raloxifene-4'-glucuronide, and raloxifene-6-sulfate in rat plasma samples for pharmacokinetic studies. The separation of the analytes was achieved on a Waters BEH C₁₈ column. Water (0.1% formic acid) and acetonitrile were used as the mobile phases for elution. A one-step protein precipitation using a mixture solvent was applied for plasma sample preparation. The method was validated following the FDA guidance. The results showed that the linear range were 1.95-1000 nM for raloxifene-6-glucuronide, and raloxifene-4'-glucuronide, 0.195-100 nM for raloxifene-6-sulfate, and 0.195-200 nM for raloxifene, respectively. The lower limit of quantification was 1.95, 1.95, 0.195, and 0.195 nM for raloxifene-6-glucuronide, raloxifene-4'-glucuronide, raloxifene-6-sulfate, and raloxifene, respectively. Only 20 µl of plasma sample was required since the method is sensitive. The intra- and interday variance is <15% and the accuracy is within 85-115%. The variance of matrix effect and recovery were <15%. The method was successfully applied in a pharmacokinetic study in rats with oral administration of raloxifene.

Raloxifene as Treatment for Various Types of Brain Injuries and Neurodegenerative Diseases: A Good Start

Recent studies have shown that the selective estrogen receptor modulator (SERM) raloxifene had pronounced protective effects against progressing brain damage after traumatic brain injury (TBI) in mice. These studies, indicating beneficial effects of raloxifene for brain health, prompted the study of the history and present state of knowledge of this topic. It appears that, apart from raloxifene, to date, four nonrelated compounds have shown comparable beneficial effects—fucoidan, pifithrin, SMM-189 (5-dihydroxy-phenyl]-phenyl-methanone), and translocator protein (TSPO) ligands. Raloxifene, however, is ahead of the field, as for more than two decades it has been used in medical practice for various chronic ailments in humans. Thus, apart from different types of animal and cell culture studies, it has also been assessed in various human clinical trials, including assaying its effects on mild cognitive impairments. Regarding cell types, raloxifene protects neurons from cell death, prevents glial activation, ameliorates myelin damage, and maintains health of endothelial cells. At whole central nervous system (CNS) levels, raloxifene ameliorated mild cognitive impairments, as seen in clinical trials, and showed beneficial effects in animal models of Parkinson’s disease. Moreover, with stroke and TBI in animal models, raloxifene showed curative effects. Furthermore, raloxifene showed healing effects regarding multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS) in cell culture. The adverse biological signals typical of these conditions relate to neuronal activity, neurotransmitters and their receptors, plasticity, inflammation, oxidative stress, nitric oxide, calcium homeostasis, cell death, behavioral impairments, etc. Raloxifene favorably modulates these signals toward cell health—on the one hand, by modulating gene expression of the relevant proteins, for example by way of its binding to the cell nuclear estrogen receptors ERα and ERβ (genomic effects) and, on the other hand (nongenomic effects) by modulation of mitochondrial activity, reduction of oxidative stress and programmed cell death, maintaining metabolic balance, degradation of Abeta, and modulation of intracellular cholesterol levels. More specifically regarding Alzheimer’s disease, raloxifene may not cure diagnosed Alzheimer’s disease. However, the onset of Alzheimer’s disease may be delayed or arrested by raloxifene’s capability to attenuate mild cognitive impairment. Mild cognitive impairment is a condition that may precede diagnosis of Alzheimer’s disease. In this review, relatively new insights are addressed regarding the notion that Alzheimer’s disease can be caused by bacterial (as well as viral) infections, together with the most recent findings that raloxifene can counteract infections of at least some bacterial and viral strains. Thus, here, an overview of potential treatments of neurodegenerative disease by raloxifene is presented, and attention is paid to subcellular molecular biological pathways that may be involved.

Selective estrogen receptor modulators in the prevention of breast cancer in premenopausal women: a review

The detection of premenopausal women at high risk of breast cancer is key to chemoprevention. Therapy with selective estrogen receptor modulators (SERMs) induces a significant antiproliferative effect in estrogen receptor (ER) positive breast cancer. This review was designed according the guidelines of the 2009 PRISMA statement. Searching different databases, including PubMed, MedlinePlus, PLoS One, Cochrane Breast Cancer Specialized Register, Clinical Trials.gov and American Society of Clinical Oncology. From 168 records screened, 15 full text articles were assessed for eligibility and only 7 studies met the inclusion criteria. Three of the studies included analyzed changes in Ki-67 expression, revealing weaker expression after treatment with acolbifene and raloxifene (P<0.001). Three studies also analyzed the breast volume by magnetic resonance imagining (MRI) and demonstrate a significant difference after 1 year with raloxifene treatment (P=0.0017). Moreover, a 20% reduction in breast density was observed after a 2-year treatment with tamoxifen in premenopausal women. SERMs reduce the risk of developing breast cancer. The studies reviewed here demonstrate the modulation of Ki-67 expression and changes in breast density, suggesting an important preventive role for this group of drugs in prevention for premenopausal women at high risk of developing breast cancer.

Preventive drug therapy and contralateral breast cancer: summary of the evidence of clinical trials and observational studies

Background: Breast cancer patients have a lifelong 2-4-fold increased risk of developing a second primary tumor in the contralateral breast compared with the risk for a first primary breast cancer in the general female population. Prevention of contralateral breast cancer (CBC) has received increased attention during recent decades. Here, we summarize and discuss the available literature on drug preventive therapy and CBC.Results: The endocrine-targetting drugs, tamoxifen and aromatase inhibitors are used as standard adjuvant treatment for estrogen receptor (ER)-positive breast cancer. Both are associated with relative risk reductions of CBC of up to 50%, but incur serious side effects. Several prescription drugs originally developed for other purposes, including bisphosphonates, statins, non-steroidal anti-inflammatory drugs, metformin, anti-hypertensives and retinoids, have shown anti-cancer activity in preclinical models. However, results of observational studies on CBC are sparse and inconsistent, with only statins demonstrating promise as preventive agents and a potential treatment option for ER-negative breast cancer patients.Conclusion: Future studies are needed to assess the effect of statins in risk reduction and to identify other drugs with chemopreventive potential against CBC. Eventually, efforts must be directed towards identifying those breast cancer patients likely to benefit most from specific preventive therapies.

Raloxifene inhibits adipose tissue inflammation and adipogenesis through Wnt regulation in ovariectomized rats and 3 T3-L1 cells

BACKGROUND

Loss of ovarian function, as in menopause or after ovariectomy (OVX), is closely associated with obesity and white adipose tissue (WAT) inflammation. Estrogen replacement protects against postmenopausal obesity but increases the risks of carcinogenesis. In the present study, we investigated the effects of long-term treatment of raloxifene (RAL), a selective estrogen receptor modulator, on the features of estrogen deficiency-induced obesity and explored the involvement of canonical and non-canonical Wnt regulation in vivo and in vitro.

METHODS

Adult female rats received bilateral OVX and divided into 5 groups: (1) Sham, (2) OVX, (3) OVX + E₂: OVX rats were administered with E₂ (50 μg/kg, s.c., 3 times/week), (4) OVX + RAL: OVX rats were treated with RAL (gavage, 1 mg/kg/day) suspended in 0.8% carboxymethylcellulose (CMC), (5) OVX + CMC: 0.8% CMC as vehicle control. All treatments were given for 8 weeks beginning at 1 week after OVX. In 3 T3-L1 cells, the effects of RAL on adipogenesis and lipopolysaccharide (LPS)-induced inflammation were evaluated.

RESULTS

Treatment with RAL significantly decreased body weight, visceral fat pad mass, adipocyte size and plasma levels of glucose but increased plasma adiponectin. RAL reduced the elevation of HIF-1α, VEGF-A and proinflammatory cytokines (MCP-1 and TNF-α) expression by inhibition of NF-κB p65 and JNK cascades in retroperitoneal WAT. This anti-inflammatory capacity of RAL may result from upregulation of secreted frizzle-related protein 5 (SFRP5), an adipokine that repressed Wnt5a signaling. Furthermore, RAL inhibited adipogenic factors such as PPAR-γ, C/EBP-α, and FABP4, and preserved canonical Wnt10b/β-catenin protein expression. In 3 T3-L1 adipocytes, RAL (20 μM) diminished lipid accumulation and inhibited adipogenic factors accompanied with the induction of β-catenin, which were effectively reversed by the β-catenin inhibitor IWR-1-endo. In addition, RAL reduced LPS-induced NF-κB p65 and p-IκB expression as well as TNF-α secretion. Suppression of SFRP5 by small interfering RNA significantly abrogated the anti-inflammatory effects of RAL.

CONCLUSIONS

Distinct activation of canonical β-catenin on inhibition of adipogenesis and non-canonical SFRP5 on suppression of WAT inflammation may contribute to the beneficial effects of RAL. Therefore, this study provides a rationale for the therapeutic potential of RAL for postmenopausal obesity.

Impacts of Psychological Stress on Osteoporosis: Clinical Implications and Treatment Interactions

The significant biochemical and physiological effects of psychological stress are beginning to be recognized as exacerbating common diseases, including osteoporosis. This review discusses the current evidence for psychological stress-associated mental health disorders as risk factors for osteoporosis, the mechanisms that may link these conditions, and potential implications for treatment. Traditional, alternative, and adjunctive therapies are discussed. This review is not intended to provide therapeutic recommendations, but, rather, the goal of this review is to delineate potential interactions of psychological stress and osteoporosis and to highlight potential multi-system implications of pharmacological interventions. Review of the current literature identifies several potentially overlapping mechanistic pathways that may be of interest (e.g., glucocorticoid signaling, insulin-like growth factor signaling, serotonin signaling) for further basic and clinical research. Current literature also supports the potential for cross-effects of therapeutics for osteoporosis and mental health disorders. While studies examining a direct link between osteoporosis and chronic psychological stress are limited, the studies reviewed herein suggest that a multi-factorial, personalized approach should be considered for improved patient outcomes in populations experiencing psychological stress, particularly those at high-risk for development of osteoporosis.

The effect of raloxifene on bone marrow adipose tissue and bone turnover in postmenopausal women with osteoporosis

In patients with postmenopausal osteoporosis low bone volume is associated with high bone marrow adipose tissue (MAT). Moreover, high MAT is associated with increased fracture risk. This suggests an interaction between MAT and bone turnover, however literature remains equivocal. Estrogen treatment decreases MAT, but the effect of raloxifene, a selective estrogen receptor modulator (SERM) registered for treatment of postmenopausal osteoporosis, on MAT is not known. The aim of this study is 1] to determine the effect of raloxifene on MAT and 2] to determine the relationship between MAT and bone turnover in patients with osteoporosis. Bone biopsies from the MORE trial were analyzed. The MORE trial investigated the effects of raloxifene 60 or 120mg per day versus placebo on bone metabolism and fracture incidence in patients with postmenopausal osteoporosis. We quantified MAT in iliac crest biopsies obtained at baseline and after 2years of treatment (n=53; age 68.2±6.2years). Raloxifene did not affect the change in MAT volume after 2years compared to baseline (placebo: 1.89±10.84%, raloxifene 60mg: 6.31±7.22%, raloxifene 120mg: -0.77±10.72%), nor affected change in mean adipocyte size (placebo: 1.45 (4.45) μm, raloxifene 60mg: 1.45 (4.35) μm, raloxifene 120mg: 0.81 (5.21) μm). Adipocyte number tended to decrease after placebo treatment (-9.92 (42.88) cells/mm²) and tended to increase during raloxifene 60mg treatment (13.27 (66.14) cells/mm²) while adipocyte number remained unchanged in the raloxifene 120mg group, compared to placebo (3.06 (39.80) cells/mm², Kruskal-Wallis p=0.055, post hoc: placebo vs raloxifene 60mg p=0.017). MAT volume and adipocyte size were negatively associated with osteoclast number at baseline (R²=0.123, p=0.006 and R²=0.098, p=0.016 respectively). Furthermore adipocyte size was negatively associated with osteoid surface (R²=0.067, p=0.049). Finally, patients with vertebral fractures had higher MAT volume (50.82 (8.80)%) and larger adipocytes (55.75 (3.14) μm) compared to patients without fractures (45.58 (12.72)% p=0.032, 52.77 (3.73) μm p=0.004 respectively). In conclusion, raloxifene did not affect marrow adipose tissue, but tended to increase adipocyte number compared to placebo. At baseline MAT volume and adipocyte size were associated with bone resorption, and adipocyte size was associated with osteoid surface, suggesting an interaction between bone marrow adipocytes and bone turnover. In addition, we found that high MAT volume and larger adipocyte size are associated with prevalent vertebral fractures in postmenopausal women with osteoporosis, indicating that adipocyte size affects bone quality independent of bone volume.

Bone health and evaluation of bone mineral density in patients with premature ovarian insufficiency

Oestrogens exert an influence on skeletal homeostasis during growth and adulthood. Regulation of osteoclasts and osteoblasts generation and apoptosis and prolongation of the lifespan of osteocytes are some of their actions on bone metabolism. Premature ovarian insufficiency (POI) and associated loss of oestrogen action on osteoclasts leads to trabecular perforation and loss of connectivity. Lack of oestrogens acting on osteoblast progenitors also causes a decrease in critical bone mass. Postmenopausal hypoestrogenism is associated with an increase in the number of lymphocyte B-cells expressing nuclear factor κB ligand (RANKL) in the bone marrow and elevated expression of RANKL by B-cells. Increased concentration of RANKL stimulates activation of osteoclasts and leads to oestrogen deficiency-associated bone loss. It has been proven that women with POI have decreased bone mineral density (BMD) measured in lumbar spine and femoral neck. The loss of bone mass associated with oestrogen deficiency is greater in trabecular than in cortical bone, thus women with POI have a significant decrease in BMD, particularly in the lumbar spine vertebrae. Smoking cessation, weight-bearing, and muscle-strengthening exercises on most days of the week, avoidance of excessive alcohol intake, and adequate supplementation of calcium and vitamin D are the main lifestyle rules necessary to avoid decline in BMD. The most important component of decreased BMD treatment in POI patients is systemic hormonal replacement therapy (HRT). HRT should provide hormonal balance and should mimic normal ovarian function as much as possible.

Raloxifene/SBE-β-CD Inclusion Complexes Formulated into Nanoparticles with Chitosan to Overcome the Absorption Barrier for Bioavailability Enhancement

Raloxifene (RXF) is a hormone-like medication used for treating postmenopausal osteoporosis and estrogen-dependent breast cancer, yet associated with bad low bioavailability due to poor solubility. This study was intended to develop cyclodextrin/chitosan nanoparticles (ccNPs) for oral delivery of RXF in order to enhance the oral bioavailability. RXF-loaded ccNPs (RXF-ccNPs) were prepared by cyclodextrin inclusion followed by complexation with chitosan. RXF-ccNPs were fully characterized by particle size, morphology and in vitro drug release. The oral delivery efficacy and transepithelial transport potential were evaluated by pharmacokinetics, in situ single-pass intestinal perfusion, cellular uptake and ex vivo imaging. The resulting RXF-ccNPs were around 165 nm in particle size with a narrow distribution. The oral bioavailability of RXF was enhanced by 2.6 folds through ccNPs compared to RXF suspensions in rats. It was shown that RXF-ccNPs could improve the intestinal permeability of RXF, increase the cellular uptake of RXF and facilitate its transport across the absorptive epithelia. The results indicate that our developed ccNPs based on sulfobutylether-β-cyclodextrin and oligochitosan are a promising vehicle to orally deliver poorly water-soluble drugs over and above RXF.

Translational Significance of Selective Estrogen Receptor Modulators in Psychiatric Disorders

Accumulating data from various clinical trial studies suggests that adjuvant therapy with ovarian hormones (estrogens) could be effective in reducing cognitive deficit and psychopathological symptoms in women with psychiatric disorders. However, estrogen therapy poses serious limitations and health issues including feminization in men and increased risks of thromboembolism, hot flashes, breast hyperplasia, and endometrium hyperplasia when used for longer duration in older women (aged ≥ 60 years) or in women who have genetic predispositions. On the other hand, selective estrogen receptor modulators (SERMs), which may (or may not) carry some risks of hot flashes, thromboembolism, breast hyperplasia, and endometrial hyperplasia, are generally devoid of feminization effect. In clinical trial studies, adjuvant therapy with tamoxifen, a triphenylethylene class of SERM, has been found to reduce the frequency of manic episodes in patients with bipolar disorder, whereas addition of raloxifene, a benzothiophene class of SERM, to regular doses of antipsychotic drugs has been found to reduce cognitive deficit and psychological symptoms in men and women with schizophrenia, including women with treatment refractory psychosis. These outcomes together with potent neurocognitive, neuroprotective, and cardiometabolic properties suggest that SERMs could be the potential targets for designing effective and safer therapies for psychiatric disorders.

Müllerian intra-abdominal carcinomatosis in hereditary breast ovarian cancer syndrome: implications for risk-reducing surgery

More than 40 years ago Lynch et al. described several multigenerational breast cancer family pedigrees which demonstrated autosomal dominant inheritance of a trait(s) that increased risks for both breast and ovarian cancers. Mutation carriers in at least 90 % of these hereditary breast ovarian cancer (HBOC) syndrome families have been linked to cancer-associated mutations in the genes BRCA1 and BRCA2. This review focuses on the contributions of Lynch, colleagues and collaborators and pertinent literature, toward defining the HBOC syndrome, the cancer risks that the inherited adverse mutations convey, the gynecologic tissues and organs from which the malignancy may arise to disseminate throughout the pelvic and abdominal organs and peritoneum and how this information can be used to reduce the risk and morbidities of intra-abdominal carcinomatosis in effected individuals.

Selective Estrogen Receptor Modulators: Cannabinoid Receptor Inverse Agonists with Differential CB1 and CB2 Selectivity

Selective estrogen receptor modulators (SERMs) are used to treat estrogen receptor (ER)-positive breast cancer and osteoporosis. Interestingly, tamoxifen and newer classes of SERMs also exhibit cytotoxic effects in cancers devoid of ERs, indicating a non-estrogenic mechanism of action. Indicative of a potential ER-independent target, reports demonstrate that tamoxifen binds to cannabinoid receptors (CBRs) with affinity in the low μM range and acts as an inverse agonist. To identify cannabinoids with improved pharmacological properties relative to tamoxifen, and further investigate the use of different SERM scaffolds for future cannabinoid drug development, this study characterized the affinity and activity of SERMs in newer structural classes at CBRs. Fourteen SERMs from five structurally distinct classes were screened for binding to human CBRs. Compounds from four of five SERM classes examined bound to CBRs. Subsequent studies fully characterized CBR affinity and activity of one compound from each class. Ospemifine (a triphenylethylene) selectively bound to CB1Rs, while bazedoxifine (an indole) bound to CB2Rs with highest affinity. Nafoxidine (a tetrahydronaphthalene) and raloxifene (RAL; a benzothiaphene) bound to CB1 and CB2Rs non-selectively. All four compounds acted as inverse agonists at CB1 and CB2Rs, reducing basal G-protein activity with IC₅₀ values in the nM to low μM range. Ospemifine, bazedoxifene and RAL also acted as inverse agonists to elevate basal intracellular cAMP levels in intact CHO-hCB2 cells. The four SERMs examined also acted as CB1 and CB2R antagonists in the cAMP assay, producing rightward shifts in the concentration-effect curve of the CBR agonist CP-55,940. In conclusion, newer classes of SERMs exhibit improved pharmacological characteristics (e.g., in CBR affinity and selectivity) relative to initial studies with tamoxifen, and thus suggest that different SERM scaffolds may be useful for development of safe and selective drugs acting via CBRs.

Neurocognitive, Neuroprotective, and Cardiometabolic Effects of Raloxifene: Potential for Improving Therapeutic Outcomes in Schizophrenia

Raloxifene is a selective estrogen receptor modulator that has been approved for treating osteoporosis and breast cancer in high-risk postmenopausal women. However, recent evidence suggests that raloxifene adjunct therapy improves cognition and reduces symptom severity in men and women with schizophrenia. In animal models, raloxifene increases forebrain neurogenesis and enhances working memory and synaptic plasticity. It may consequently repair the neuronal and synaptic connectivity that is disrupted in schizophrenia. It also reduces oxidative stress and neuroinflammation, which are potent etiological factors in the neuropathology of schizophrenia. Furthermore, in postmenopausal women, raloxifene reduces the risks for atherosclerosis, diabetes mellitus, and weight gain, which are serious adverse effects associated with long-term antipsychotic treatment in schizophrenia; therefore, it may improve the safety and efficacy of antipsychotic drugs. In this review, recent insights into the neurocognitive, neuroprotective, and cardiometabolic effects of raloxifene in relation to therapeutic outcomes in schizophrenia are discussed.

Research Resources for Nuclear Receptor Signaling Pathways

Nuclear receptor (NR) signaling pathways impact cellular function in a broad variety of tissues in both normal physiology and disease states. The complex tissue-specific biology of these pathways is an enduring impediment to the development of clinical NR small-molecule modulators that combine therapeutically desirable effects in specific target tissues with suppression of off-target effects in other tissues. Supporting the important primary research in this area is a variety of web-based resources that assist researchers in gaining an appreciation of the molecular determinants of the pharmacology of a NR pathway in a given tissue. In this study, selected representative examples of these tools are reviewed, along with discussions on how current and future generations of tools might optimally adapt to the future of NR signaling research.

Raloxifene as an Adjunctive Treatment for Postmenopausal Women With Schizophrenia: A 24-Week Double-Blind, Randomized, Parallel, Placebo-Controlled Trial

The potential therapeutic utility of estrogens in schizophrenia is increasingly being recognized. Raloxifene, a selective estrogen receptor modulator, appears to act similarly to estrogens on dopamine and serotonin brain systems. One previous trial by our team found that raloxifene was useful to improve negative, positive, and general psychopathological symptoms, without having the negative side effects of estrogens. In this study, we assess the utility of raloxifene in treating negative and other psychotic symptoms in postmenopausal women with schizophrenia exhibiting prominent negative symptoms. This was a 24-week, randomized, parallel, double-blind, placebo-controlled study. Patients were recruited from the inpatient and outpatient departments of Parc Sanitari Sant Joan de Déu, Hospital Universitari Institut Pere Mata, and Corporació Sanitària Parc Taulí. Seventy postmenopausal women with schizophrenia (DSM-IV) were randomized to either adjunctive raloxifene (38 women) or adjunctive placebo (32 women). Psychopathological symptoms were assessed at baseline and at weeks 4, 12, and 24 with the Positive and Negative Syndrome Scale (PANSS) and the Scale for the Assessment of Negative Symptoms (SANS). The addition of raloxifene (60 mg/d) to regular antipsychotic treatment significantly reduced negative (P = .027), general (P = .003), and total symptomatology (P = .005) measured with the PANSS during the 24-week trial, as compared to women receiving placebo. Also Alogia SANSS subscale improved more in the raloxifene (P = .048) than the placebo group. In conclusion, raloxifene improved negative and general psychopathological symptoms, compared with antipsychotic medication alone, in postmenopausal women with schizophrenia. These data replicate our previous results with a larger sample and a longer follow-up.

TRIAL REGISTRATION

NCT01573637.

Structural features underlying raloxifene's biophysical interaction with bone matrix

Raloxifene, a selective estrogen receptor modulator (SERM), reduces fracture risk at least in part by improving the mechanical properties of bone in a cell- and estrogen receptor-independent manner. In this study, we determined that raloxifene directly interacts with the bone tissue. Through the use of multiple and complementary biophysical techniques including nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR), we show that raloxifene interacts specifically with the organic component or the organic/mineral composite, and not with hydroxyapatite. Structure-activity studies reveal that the basic side chain of raloxifene is an instrumental determinant in the interaction with bone. Thus, truncation of portions of the side chain reduces bone binding and also diminishes the increase in mechanical properties. Our results support a model wherein the piperidine interacts with bone matrix through electrostatic interactions with the piperidine nitrogen and through hydrophobic interactions (van der Waals) with the aliphatic groups in the side chain and the benzothiophene core. Furthermore, in silico prediction of the potential binding sites on the surface of collagen revealed the presence of a groove with sufficient space to accommodate raloxifene analogs. The hydroxyl groups on the benzothiophene nucleus, which are necessary for binding of SERMs to the estrogen receptor, are not required for binding to the bone surface, but mediate a more robust binding of the compound to the bone powder. In conclusion, we report herein a novel property of raloxifene analogs that allows them to interact with the bone tissue through potential contacts with the organic matrix and in particular collagen.

Coexistence of adenomyosis and endometrioid endometrial cancer: Role in surgical guidance and prognosis estimation

The aim of the current study was to diagnose the concomitant presence of adenomyosis (AM) in endometrioid endometrial cancer (EEC) in order to evaluate its value as an oncological prognostic marker. A retrospective analysis of 289 patients diagnosed with EEC who underwent total hysterectomy, bilateral salpingo-oophorectomy and pelvic-lymphadenectomy was conducted. The total cohort included 37 patients in Group A (those with concomitant AM and EEC) and 252 patients in Group B (those affected only by EEC). The following factors were evaluated: Presence or absence of AM, tumor grade, depth of myometrial invasion, tumor size, lymphovascular space involvement, lymph node status, peritoneal cytology, concomitant detection of endometrial atypical-hyperplasia or polypoid endometrial features and tumor stage according to the International Federation of Gynecology and Obstetrics (FIGO) classification. Uterine examination of different sections of uterine cervix, corpus, myomas and cervical or endometrial polyps was performed. The diagnosis of AM was confirmed when the distance between the lower border of the endometrium and the foci of the endometrial glands and stroma was >2.5 mm. Parametric and nonparametric statistical tests were performed when possible; continuous variables were analyzed using a Student's t-test, and categorical variables were analyzed by the χ² test or Fisher's exact test. The association between FIGO stage and group was determined to be significant: 83.8% of Group A patients were categorized as FIGO stage I, vs. 68.7% of Group B patients. In addition, Group A was associated with lower grades in FIGO stage, myometrial invasion, lymphovascular space involvement, lymph node involvement and tumor size. The findings suggest that the intraoperative evaluation of the presence of AM in patients with EEC may aid surgeons in estimating oncological risk and in selecting the most appropriate surgical treatment.

Down-regulation of osteopontin mediates a novel mechanism underlying the cytostatic activity of TGF-β

PURPOSE

Loss of a cytostatic response to TGF-β has been implicated in multiple hyper-proliferative disorders, including cancer. Although several key genes involved in the cytostatic activity of TGF-β have in the past been identified, its exact mode of action is yet to be elucidated. A comprehensive understanding of the mechanisms underlying the cytostatic activity of TGF-β may open up new avenues for the development of therapeutic strategies.

METHODS

Quantitative real-time RT-PCR was used to assess osteopontin (OPN) gene expression in human hepatoma-derived Huh-7 and lung adenocarcinoma-derived A549 cells. Reporter assays using an OPN promoter-luciferase construct and its mutated counterparts were performed to assess its transcriptional activity. Binding of Smad4 to the OPN gene promoter was investigated using chromatin immunoprecipitation (CHIP). The putative role of Smad4 in OPN gene expression down-regulation was also assessed using a shRNA-mediated knockdown strategy. The anti-proliferative effect of TGF-β on different cancer-derived cell lines was determined using the cell proliferation reagent WST-1.

RESULTS

We found that the OPN expression levels dose-dependently decreased in TGF-β-treated Huh-7 and A549 cells. Our reporter assays indicated that this TGF-β-induced repression occurred at the transcriptional level, and could largely be abrogated by disruption of an element (TIE2) similar to the TGF-β inhibitory element found in other TGF-β-repressed genes. Our CHIP assay revealed that the Smad protein complex specifically binds to the OPN gene promoter, and that the TGF-β-mediated inhibition of OPN was lost upon shRNA-mediated knockdown of Smad4. Moreover, we found that the deregulation of OPN gene expression by TGF-β occurred concomitantly with loss of the TGF-β anti-proliferative response, whereas a neutralizing anti-OPN antibody partially restored this response.

CONCLUSIONS

Our results indicate that the OPN gene is a direct target of Smad-mediated TGF-β signaling, implying that OPN expression inhibition serves as a novel mechanism underlying the cytostatic activity of TGF-β.

Sex hormones and oxytocin augmentation strategies in schizophrenia: A quantitative review

INTRODUCTION

Sex differences in incidence, onset and course of schizophrenia suggest sex hormones play a protective role in the pathophysiology. Such a role is also proposed for oxytocin, another important regulator of reproduction function. Evidence on the efficacy of sex hormones and oxytocin in the treatment of schizophrenia is summarized.

METHODS

Double-blind, placebo-controlled, randomized studies were included, examining augmentation with estrogens, selective estrogen receptor modulators (SERMs), testosterone, dehydroepiandrosterone (DHEA), pregnenolone, and oxytocin. Outcome measures were total symptom severity, positive and negative symptom subscores, and cognition. In meta-analyses, combined weighted effect sizes (Hedges' g) per hormone were calculated.

RESULTS

Twenty-four studies were included, examining 1149 patients. Significant effects were found for estrogen action (k=10), regarding total symptoms (Hedges' g=0.63, p=0.001), positive (Hedges' g=0.42, p<0.001), and negative symptoms (Hedges' g=0.35, p=0.001). Subgroup analyses yielded significant results for estrogens in premenopausal women (k=6) for total, positive, and negative symptoms, and for the SERM raloxifene in postmenopausal women (k=3) for total and negative, but not positive symptoms. Testosterone augmentation in males (k=1) was beneficial only for negative symptoms (Hedges' g=0.82, p=0.027). No overall effects were found for DHEA (k=4), pregnenolone (k=4), and oxytocin (k=6). Results for cognition (k=12) were too diverse for meta-analyses, and inspection of these data showed no consistent benefit.

CONCLUSIONS

Estrogens and SERMs could be effective augmentation strategies in the treatment of women with schizophrenia, although potential side effects, partially associated with longer duration use, should be taken into account. Future trials are needed to study long-term effects and effects on cognition.

The Dual Estrogen Receptor α Inhibitory Effects of the Tissue-Selective Estrogen Complex for Endometrial and Breast Safety

The conjugated estrogen /: bazedoxifene tissue-selective estrogen complex (TSEC) is designed to minimize the undesirable effects of estrogen in the uterus and breast tissues and to allow the beneficial effects of estrogen in other estrogen-target tissues, such as the bone and brain. However, the molecular mechanism underlying endometrial and breast safety during TSEC use is not fully understood. Estrogen receptor α (ERα)-estrogen response element (ERE)-DNA pull-down assays using HeLa nuclear extracts followed by mass spectrometry-immunoblotting analyses revealed that, upon TSEC treatment, ERα interacted with transcriptional repressors rather than coactivators. Therefore, the TSEC-mediated recruitment of transcriptional repressors suppresses ERα-mediated transcription in the breast and uterus. In addition, TSEC treatment also degraded ERα protein in uterine tissue and breast cancer cells, but not in bone cells. Interestingly, ERα-ERE-DNA pull-down assays also revealed that, upon TSEC treatment, ERα interacted with the F-box protein 45 (FBXO45) E3 ubiquitin ligase. The loss-of- and gain-of-FBXO45 function analyses indicated that FBXO45 is involved in TSEC-mediated degradation of the ERα protein in endometrial and breast cells. In preclinical studies, these synergistic effects of TSEC on ERα inhibition also suppressed the estrogen-dependent progression of endometriosis. Therefore, the endometrial and breast safety effects of TSEC are associated with synergy between the selective recruitment of transcriptional repressors to ERα and FBXO45-mediated degradation of the ERα protein.

Raloxifene glucuronidation in liver and intestinal microsomes of humans and monkeys: contribution of UGT1A1, UGT1A8 and UGT1A9

1. Raloxifene is an antiestrogen that has been marketed for the treatment of osteoporosis, and is metabolized into 6- and 4'-glucuronides by UDP-glucuronosyltransferase (UGT) enzymes. In this study, the in vitro glucuronidation of raloxifene in humans and monkeys was examined using liver and intestinal microsomes and recombinant UGT enzymes (UGT1A1, UGT1A8 and UGT1A9). 2. Although the K(m) and CL(int) values for the 6-glucuronidation of liver and intestinal microsomes were similar between humans and monkeys, and species differences in Vmax values (liver microsomes, humans > monkeys; intestinal microsomes, humans < monkeys) were observed, no significant differences were noted in the K(m) or S50, Vmax and CL(int) or CLmax values for the 4'-glucuronidation of liver and intestinal microsomes between humans and monkeys. 3. The activities of 6-glucuronidation in recombinant UGT enzymes were UGT1A1 > UGT1A8 >UGT1A9 for humans, and UGT1A8 > UGT1A1 > UGT1A9 for monkeys. The activities of 4'-glucuronidation were UGT1A8 > UGT1A1 > UGT1A9 in humans and monkeys. 4. These results demonstrated that the profiles for the hepatic and intestinal glucuronidation of raloxifene by microsomes were moderately different between humans and monkeys.

Levonorgestrel Inhibits Human Endometrial Cell Proliferation through the Upregulation of Gap Junctional Intercellular Communication via the Nuclear Translocation of Ser255 Phosphorylated Cx43

Objects. To assess whether LNG exerts antiproliferation effects on human endometrial cells through changes of GJIC function and the phosphorylated Cx43. Methods. Cell proliferation and apoptosis of human endometrial stromal cells (HESCs) and glandular cells (HEGCs) treated with LNG in a dose- and time-dependent manner. GJIC change and further total Cx43 and serine 368 and 255 phosphorylated Cx43 were measured. Results. 5 × 10⁻⁵ mol/L LNG revealed a time-dependent inhibition of cell proliferation and an increase of apoptosis in both HESCs and HEGCs. Furthermore, these cells demonstrated a significant GJIC enhancement upon treatment with 5 × 10⁻⁵ mol/L for 48 hours. The effects of LNG were most noticeable in HESCs rather than in HEGCs. Associated with these changes, LNG induced a relative increase in total Cx43 in a time-dependent manner but not Ser368 phosphorylated Cx43. Moreover, laser scanning confocal microscope confirmed the increased expression of total Cx43 in the cytoplasm and, interestingly, the nuclear translocation of Ser255 phosphorylated Cx43. Conclusions. LNG likely inhibits the proliferation and promotes apoptosis in HESCs and HEGCs though an increase in gap junction permeability in vitro, which is achieved through the upregulation of Cx43 expression and the translocation of serine 255 phosphorylated Cx43 from the plasma to the nuclear compartment.

Statins as Targeted "Magical Pills" for the Conservative Treatment of Endometriosis: May Potential Adverse Effects on Female Fertility Represent the "Dark Side of the Same Coin"? A Systematic Review of Literature

The aim of the study was to analyze all the available evidence from both in vitro and in vivo studies regarding the efficacy of statin therapy in the treatment of endometriosis, evaluating the potential efficacy, side effects, and contraindications of their administration in humans. We focused on defining the potential benefits that the administration of statins may have on patients affected by endometriosis and the possible adverse effects of such a therapy on ovarian function and fertility profile. According to our article selection criteria, we included in the review in vitro and in vivo studies performed on human or animal models. The systematic review of literature identified 24 eligible articles, 12 of which reported evidence regarding the effects of statins on endometrial/endometriotic cells and 12 regarding their effects on ovarian function and fertility. All articles seem to emphasize the utility of statin administration in the treatment of endometriosis due to their anti-proliferative/proapoptotic effects, their ability to reduce cell viability and migration, and the inhibition of angiogenesis and anti-inflammatory activities. Regarding the potential adverse effects on gonadal activities, steroidogenesis and fertility function, no conclusive data were collected in human models (excluding women affected by polycystic ovary syndrome in which significant decline of androgen levels was reported after statin treatment), while contrasting results were reported by studies conducted in in vitro and in vivo in animal models. Despite evidence supporting statins as the potential therapeutic agent for a targeted conservative treatment of endometriosis, the uncertainties regarding their impact on gonadal function may not define them as an appropriate therapy for all young fertile women.

Comparative effects of estrogen, raloxifene and tamoxifen on endothelial dysfunction, inflammatory markers and oxidative stress in ovariectomized rats

AIM

Endothelial dysfunction is considered a premature indication of atherosclerosis and vessel damage and is present in the postmenopausal period. This study compares the influence of estrogen, raloxifene and tamoxifen on factors that affect endothelial function in ovariectomized (OVX) rats.

MAIN METHODS

The rats were divided into: SHAM; OVX; OVX+estrogen (0.5 μg/kg/day); OVX+raloxifene (2 mg/kg/day) and OVX+tamoxifen (1 mg/kg/day) groups. The acetylcholine vasorelaxation response was evaluated in the mesenteric vascular bed. The vascular oxidative stress and serum inflammatory cytokine levels were monitored, and analyses of eNOS and iNOS were performed.

KEY FINDINGS

The acetylcholine-induced responses obtained in the OVX were lower than those obtained in the SHAM, and all treatments restored this response. l-NAME reduced and equalized the acetylcholine-induced response in all groups. The attenuation of the acetylcholine-induced responses by aminoguanidine was greater in the OVX. Endothelial dysfunction in OVX was associated with oxidative stress and an increase in iNOS and decrease in eNOS expression. Except for the production of reactive oxidative species (ROS) in the OVX+tamoxifen, treatments improved the nitric oxide component of the relaxation response and normalized both the oxidative stress and the expression of those signaling pathway enzymes. Serum levels of TNF-α and IL-6 were increased in OVX, and treatments normalized these levels.

SIGNIFICANCE

Raloxifene and tamoxifen have similar anti-inflammatory effects that may be important in improving vascular dysfunction. Tamoxifen did not affect the ROS but improved endothelial dysfunction. The protective effect on endothelial function by these treatments provides evidence of their potential cardiovascular benefits in the postmenopausal period.

Raloxifene induces autophagy-dependent cell death in breast cancer cells via the activation of AMP-activated protein kinase

Raloxifene is a selective estrogen receptor modulator (SERM) that binds to the estrogen receptor (ER), and exhibits potent anti-tumor and autophagy-inducing effects in breast cancer cells. However, the mechanism of raloxifene-induced cell death and autophagy is not well-established. So, we analyzed mechanism underlying death and autophagy induced by raloxifene in MCF-7 breast cancer cells. Treatment with raloxifene significantly induced death in MCF-7 cells. Raloxifene accumulated GFP-LC3 puncta and increased the level of autophagic marker proteins, such as LC3-II, BECN1, and ATG12-ATG5 conjugates, indicating activated autophagy. Raloxifene also increased autophagic flux indicators, the cleavage of GFP from GFP-LC3 and only red fluorescence-positive puncta in mRFP-GFP-LC3-expressing cells. An autophagy inhibitor, 3-methyladenine (3-MA), suppressed the level of LC3-II and blocked the formation of GFP-LC3 puncta. Moreover, siRNA targeting BECN1 markedly reversed cell death and the level of LC3-II increased by raloxifene. Besides, raloxifene-induced cell death was not related to cleavage of caspases-7, -9, and PARP. These results indicate that raloxifene activates autophagy-dependent cell death but not apoptosis. Interestingly, raloxifene decreased the level of intracellular adenosine triphosphate (ATP) and activated the AMPK/ULK1 pathway. However it was not suppressed the AKT/mTOR pathway. Addition of ATP decreased the phosphorylation of AMPK as well as the accumulation of LC3-II, finally attenuating raloxifene-induced cell death. Our current study demonstrates that raloxifene induces autophagy via the activation of AMPK by sensing decreases in ATP, and that the overactivation of autophagy promotes cell death and thereby mediates the anti-cancer effects of raloxifene in breast cancer cells.

Role of nociceptor estrogen receptor GPR30 in a rat model of endometriosis pain

Endometriosis, the most common cause of chronic pelvic pain, is an estrogen-dependent disease in which classic estrogen receptors (ERα, ERβ) play an important role. Although recent evidence suggests that the novel G protein-coupled estrogen receptor (GPR30) also plays a key role in the progression of endometriosis, whether it is also involved in endometriosis pain is still unknown. Here we tested the hypothesis that GPR30 expressed by nociceptors contributes to endometriosis pain. Intramuscular injection of the GPR30 agonists raloxifene or 17β-estradiol produced a fast-onset, persistent, mechanical hyperalgesia at the site of the injection. Intrathecal antisense (AS) oligodeoxynucleotides (ODN), but not mismatch (MM) ODN, targeting mRNA for GPR30 markedly inhibited its protein expression in nociceptors and attenuated the mechanical hyperalgesia induced by local raloxifene or 17β-estradiol. Pretreatment with the GPR30 antagonist G-36 also inhibited the hyperalgesia induced by raloxifene or 17β-estradiol in naive control rats. Surgical implant of autologous uterine tissue onto the gastrocnemius muscle, which induces endometriosis-like lesions, produced local mechanical hyperalgesia. Intrathecal AS, but not MM, ODN targeting GPR30 mRNA reversibly inhibited the mechanical hyperalgesia at the site of endometriotic lesions. Finally, intralesional injection of the GPR30 antagonist G-36 also inhibited the mechanical hyperalgesia at the site of ectopic uterine tissue. We conclude that local GPR30 agonists produce persistent mechanical hyperalgesia in naive female rats, whereas local GPR30 antagonists inhibit mechanical hyperalgesia in a model of endometriosis pain. Thus, GPR30 expressed by nociceptors innervating ectopic uterine lesions might play a major role in endometriosis pain.

Estrogen or raloxifene during postmenopausal weight loss: adiposity and cardiometabolic outcomes

OBJECTIVE

Estrogen-based hormone therapy (HT) attenuates abdominal fat gain after menopause, but whether HT improves abdominal fat loss during weight loss is unknown. It was hypothesized that HT or a selective estrogen receptor modulator (raloxifene) would augment reductions in abdominal visceral fat during weight loss when compared to placebo, potentially increasing improvements in glucose tolerance and lipid profile.

METHODS

Healthy postmenopausal women (n = 119; age 50-70 yr) underwent a 6-month weight-loss (primarily exercise) intervention with randomization to raloxifene (60 mg/d), HT (conjugated estrogens, 0.625 mg/d), or placebo. Outcomes were change in total and abdominal (visceral and subcutaneous) fat mass, lipid profile, and fasting and post-challenge glucose and insulin.

RESULTS

Neither HT nor raloxifene augmented loss of total or abdominal fat mass during exercise-induced weight loss when compared with placebo. Weight loss-induced improvements in risk factors were similar among the three groups, except for a greater reduction in fasted glucose in the HT group (difference in change [95%CI] from placebo; -0.40 [-0.76, -0.05]) and greater reductions in LDL (-0.36 [-0.63, -0.09]) and increases in HDL (0.15 [0.07, 0.24]) in both treatment groups.

CONCLUSIONS

Postmenopausal HT and raloxifene did not increase abdominal fat loss during weight loss, but did improve some cardiometabolic outcomes.

Synthesis and anti-breast cancer evaluation of novel N-(guanidinyl)benzenesulfonamides

A series of 4-(substituted)-N-(guanidinyl)benzenesulfonamides bearing biologically active pyrazole, pyrimidine and pyridine moieties were prepared and evaluated for their anticancer activity against human tumor breast cell line (MCF7). These sulfonamides showed promising activity with IC50 values ranging from 49.5 to 70.2 μM. The structure-activity relationship of the synthesized compounds was studied. Interestingly, it was found that the most potent compounds in this study were the corresponding 2-cyanoacrylate 3, 3-oxobutanoate 4, pyrazole 6, pyridine 9 and pyrazole 13. Compounds 7 and 8 are nearly as active as Doxorubicin as reference drug with (IC50 values=70.2, 68.1 μM), while compounds 5, 10 and 11 exhibited a moderate activity.