Raloxifene: a review of its use in postmenopausal osteoporosis

From Bones to Bugs: Structure-Based Development of Raloxifene-Derived Pathoblockers That Inhibit Pyocyanin Production in Pseudomonas aeruginosa

The human pathogen Pseudomonas aeruginosa is particularly notorious for its multiple resistance mechanisms. A new concept for anti-infectives is the "pathoblocker" approach, which targets virulence factors to disarm rather than kill pathogens and thus attenuates the development of resistance. Based on the estrogen receptor modulator raloxifene, which had previously been identified as a potential biosynthesis inhibitor of the virulence factor pyocyanin via in silico screening, analogues have been developed as pathoblockers against P. aeruginosa. These compounds reduce the production of pyocyanin by binding to the phenazine biosynthesis enzyme PhzB. Structure-activity relationships (SAR) were explored using nano differential scanning fluorimetry, isothermal titration calorimetry, and 12 X-ray cocrystal structures. Compared to raloxifene, congener 20c shows a 60-fold lower affinity for the human estrogen receptor with a 15-fold increase in pyocyanin inhibitory activity. The comprehensive structural information gathered in this study paves the way for the development of improved pathoblockers with increased potency and selectivity.

Ganoderic Acid A Prevented Osteoporosis by Modulating the PIK3CA/p-Akt/TWIST1 Signaling Pathway

Osteoporosis is a disorder of decreased bone mass, microarchitectural deterioration, and fragility fractures. Ganoderma lucidum has been reported to have a variety of pharmacological activities, including immune regulation, anti-inflammation, antioxidation, sedative hypnosis, blood sugar and lipid regulation, and so on. However, the effective ingredients and the underlying mechanism of Ganoderma lucidum against osteoporosis are rarely clarified. Ganoderic acid A (GA-A), a triterpenoid, is one of the main components of Ganoderma lucidum. Our previous preliminary bioinformatic study found that it may affect bone metabolism, and it has been reported that GA-A has anti-osteoporosis potential via regulating MC3T3-E1 cells' osteogenic differentiation activity. Therefore, the aim of this study is to investigate the effects of Ganoderic acid A in preventing osteoporosis and uncover the potential mechanisms. In vivo, the 8-week-old C57BL/6J female mice were used to establish the osteoporosis model by ovariectomy (OVX). Two cell lines, MC3T3-E1 cells and primary osteoblasts, were used and induced with hydrogen peroxide (H2O2) to the state of oxidative stress in osteoporosis in vitro. We showed that Ganoderic acid A could inhibit OVX-induced bone loss in a dose-dependent manner and promote H2O2-induced osteogenic differentiation of primary osteoblasts and MC3T3-E1 cells. The mechanism-related signaling pathways were identified by network pharmacology screening and verified by bioinformatics. Results predicted that the target of Ganoderic acid A might be PIK3CA. Mechanistically, we found that PIK3CA activated the Akt receptor, then inhibited the expression of TWIST1 in the osteoblasts to up-regulate the protein expression of the osteogenic-related markers. Our results suggested that Ganoderic acid A could prevent OVX-induced osteoporosis and promote H2O2-induced osteogenic differentiation of primary osteoblasts and MC3T3-E1 cells. Ganoderic acid A might play an important role in the prevention of osteoporosis by modulating the PIK3CA/p-Akt/TWIST1 signaling pathway.

Risk assessment and drug interruption guidelines for dentoalveolar surgery in patients with osteoporosis receiving anti-resorptive therapy

Medication-related osteonecrosis of the jaw (MRONJ) is a rare and challenging complication of anti-resorptive therapy. This review addresses the critical issue of risk management in patients with osteoporosis who require dentoalveolar surgery while undergoing anti-resorptive therapy. Dental practitioners should be aware of these risks; however, they should not refuse treatment based solely on them. This review discusses the risks through five major factors: invasive dentoalveolar surgeries, concomitant oral infection, type of medication, duration of medication, and preoperative drug discontinuation. Additionally, we discussed the local factors associated with dental practices. Our review underscored the importance of personalized risk assessment, considering each patient's unique drug history and oral condition. Based on a comprehensive literature review and clinical evidence, we proposed specific guidelines for preoperative drug interruption tailored to different anti-resorptive agents. These recommendations aimed to balance osteoporosis management by minimizing the risk of MRONJ during oral surgical interventions and bridging the knowledge gap in managing patients with osteoporosis requiring dental care. This review will allow clinicians to improve their practice and optimize patient outcomes by providing evidence-based strategies.

Screening of orthopedic medicines identifies raloxifene hydrochloride as a novel ferroptosis inhibitor for spinal cord injury therapy

Spinal cord injury (SCI) is a severe condition that can lead to irreversible central nervous system damage. Spinal cord injury patients frequently present with coexisting orthopedic conditions, and many of them also have underlying bone and joint diseases. Recent studies have identified ferroptosis as a significant contributor that exacerbates the progression of spinal cord injury. This study conducted a screening in common orthopedic medications, which includes anti-osteoporosis agents and calcium supplements, in order to identify potential ferroptosis inhibitors and investigate their therapeutic effects on spinal cord injury. Among the 8 drugs screened, raloxifene hydrochloride was found to significantly inhibit ferroptosis induced by RSL3 in neural cells. Subsequent studies confirmed its inhibitory effect on ferroptosis both in vitro and in vivo. It was also demonstrated that Nrf2 inhibitor Brusatol could reverse the anti-ferroptotic effect of Raloxifene hydrochloride in neural cells in vitro as well as its therapeutic effect on SCI in vivo, suggesting its inhibitory effect on ferroptosis is through Nrf2. This study identifies a novel ferroptosis inhibitor among orthopedic medicines and also confirms the therapeutic effect of Raloxifene hydrochloride on SCI. The results of the current study may provide reference for the clinical administration of SCI.

Benzylidene-isophorone hybrids with strong anticancer activity

Isophorone is a cyclic ketone that has gained significant attention in the field of organic chemistry due to its versatile reactivity and structural attributes. Derivatives of isophorone offer a broad spectrum of applications ranging from pharmaceuticals to polymer chemistry. With the aim of developing novel hybrid structures based on benzylidene by combining with isophorone scaffold, we report 3 derivatives of the benzylidene-isophorone hybrids and its potent anticancer activity. In order to optimize the anticancer activity of hybrids di-substitution of -Cl group in C2 and C6 position of phenyl ring (compound1), -OCH3 group in C2 and C5 position of phenyl ring (compound2), and -OCH3 group in C2 and C3 position of phenyl ring (compound3) of benzylidene (PhCH=) moiety were made. The structure of Compounds1,2 and 3 were elucidated using spectral and XRD methods. Compounds1,2 and 3 exhibit space group P c a 21, P-1, and P 1 21/n 1 respectively. Compounds1,2 and 3 were tested for the potent anticancer activity on MDA MB-231 cell line. All the three compounds exhibit good anticancer activity on the breast cancer cells. The parent hybrid with ortho, ortho directing -Cl (1) exhibits strong antiproliferation effect (IC50 = 0.028 µM) on MDA-MB 231 cell line. However, hybrid structures with ortho, meta directing -OCH3 (2) group showed moderate effect (IC50 = 0.061 µM) and hybrid with ortho, meta directing -OCH3 (3) substitution showed the least potent anticancer activity (IC50 = 0.074 µM). The benzylidene-isophorone hybrids exhibit anticancer effects in the following order: 1 > 2 > 3.

New potential selective estrogen receptor modulators in traditional Chinese medicine for treating menopausal syndrome

Women go through several predictable conditions and symptoms during menopause that are caused by age, changes in sex hormone levels, and other factors. Conventional menopause hormone therapy has raised serious concerns about the increased risks of cancers, blood clots, depression, etc. Selective estrogen receptor modulators (SERMs) that can be both agonists and antagonists of estrogen receptors in a tissue-specific manner are being developed to reduce the health concerns associated with menopause hormone therapy. Here, we have searched the Chinese national traditional Chinese medicine (TCM) patent database to identify potential SERM-like compounds with reduced health risks. TCM has been widely used for treating complex symptoms associated with menopause syndrome and thus can be a particularly rich source for pharmaceutical alternatives with SERM properties. After extensive literature review and molecular simulation, we conclude that protopanaxatriol, paeoniflorin, astragalin, catalpol, and hyperoside among others may be particularly promising as SERM-like compounds in treating the menopausal syndrome. Compounds in TCM hold promise in yielding comparable outcomes to hormone therapy but with reduced associated risks, thus presenting promising avenues for their clinical applications.

Clinical challenges and considerations in pharmacotherapy of osteoporosis due to menopause

INTRODUCTION

Osteoporosis is a chronic systemic skeletal disorder characterized by compromised bone strength and an increased risk of fracture, with a high prevalence worldwide. It is associated with a negative quality of life and an increased morbidity and mortality. Postmenopausal women are more prone to develop osteoporosis, and many of them will suffer at least one fragility fracture along their lifetime.

AREAS COVERED

This review starts by summarizing the pathogenesis of postmenopausal osteoporosis (PMO), with focus on the estrogen deficiency-associated bone loss. It continues with the current PMO diagnostic and fracture risk prediction tools, and it finally addresses management of PMO. All the efficacy and safety profiles of the current and future osteoporosis medications are reviewed. Furthermore, strategies to optimize the long-term disease management are discussed. For this review, only publications in English language were selected. References were extracted from PubMed, Embase, and Medline.

EXPERT OPINION

PMO disease management is far from being ideal. Educational and communication programs with the goal of improving disease knowledge and awareness, as well as reducing the health-care gap, should be implemented. In addition, most effective sequential prevention and treatment strategies should be initiated from the early menopause.

Domino Reaction Protocol to Synthesize Benzothiophene-Derived Chemical Entities as Potential Therapeutic Agents

An efficient synthesis of 3-amino-2-formyl-functionalized benzothiophenes by a domino reaction protocol and their use to synthesize a library of novel scaffolds have been reported. Reactions of ketones and 1,3-diones with these amino aldehyde derivatives formed a series of benzothieno[3,2-b]pyridine and 3,4-dihydro-2H-benzothiopheno[3,2-b]quinolin-1-one, respectively. A plausible mechanism for the formation of fused pyridine derivatives by the Friedlander reaction has been elucidated by density functional theory (DFT) calculations. Furthermore, hydrazones were obtained by reacting the aldehyde functional group of benzothiophenes with different hydrazine derivatives. Preliminary screening of these compounds against several bacterial strains and cancer cell lines led to the discovery of several hit molecules. Hydrazone and benzothieno[3,2-b]pyridine derivatives are potent cytotoxic and antibacterial agents, respectively. One of the potent compounds effected ∼97% growth inhibition of the LOX IMVI cell line at 10 μM concentration.

Recent advance of small-molecule drugs for clinical treatment of osteoporosis: A review

Osteoporosis is a metabolic bone disorder typified by a reduction in bone mass and structural degradation of bone tissue, leading to heightened fragility and vulnerability to fractures. The incidence of osteoporosis increases with age, making it a significant public health challenge. The pathogenesis of osteoporosis involves an imbalance between osteoblast-mediated bone formation and resorption. The current treatment options for osteoporosis include bisphosphonates, hormone replacement therapy (HRT), selective estrogen receptor modulators (SERMs), and denosumab. The recent advances in small-molecule drugs for the clinical treatment of osteoporosis offer promising options for improving bone health and reducing fracture risk. This review aims to provide an overview of the clinical applications and synthetic routes of representative small-molecule drugs for the treatment of osteoporosis. A comprehensive understanding of the synthetic methods of drug molecules for osteoporosis may inspire the development of new, more effective, and practical synthetic techniques for treating this condition.

Examining the role of cannabinoids on osteoporosis: a review

PURPOSE

Prior research studies have shown that the endocannabinoid system, influenced by CBD and THC, plays a role in bone remodeling. As both the research on cannabis and use of cannabis continue to grow, novel medicinal uses of both its constituents as well as the whole plant are being discovered. This review examines the role of cannabinoids on osteoporosis, more specifically, the endocannabinoid system and its role in bone remodeling and the involvement of the cannabinoid receptors 1 and 2 in bone health, as well as the effects of Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD), and synthetic cannabinoids on bone.

METHODS

A comprehensive literature search of online databases including PUBMED was utilized.

RESULTS

A total of 29 studies investigating the effects of cannabis and/or its constituents as well as the activation or inactivation of cannabinoid receptors 1 and 2 were included and discussed.

CONCLUSION

While many of the mechanisms are still not yet fully understood, both preclinical and clinical studies show that the effects of cannabis mediated through the endocannabinoid system may prove to be an effective treatment option for individuals with osteoporosis.

Raloxifene/Vitamin D Combination Therapy vs. Raloxifene Monotherapy on Serum 25-Hydroxy-Vitamin D Level among Postmenopausal Women with Osteoporosis or Osteopenia: A Randomized Controlled Trial

Background

We compared the efficacy of a fixed dose combination of raloxifene 60 mg/vitamin D 800 IU to raloxifene 60 mg alone on vitamin D status, as indicated by change in serum 25-hydroxy-vitamin D (25[OH]D) levels.

Methods

In this 16-week, open-label, randomized, active controlled, multicenter clinical trial conducted in 4 university-affiliated hospitals in Korea, postmenopausal women aged 55 to 70 years with osteoporosis or osteopenia were randomly assigned in a 1:1 ratio to receive raloxifene 60 mg/cholecalciferol 800 IU combination therapy or raloxifene 60 mg monotherapy. Primary endpoint was change in serum 25(OH)D level from baseline to 16 weeks after the intervention.

Results

A total of 96 participants were randomly assigned to raloxifene/vitamin D combination therapy (N=49) and raloxifene monotherapy (N=47) groups. At week 16, serum 25(OH)D level increased from baseline, only in the raloxifene/vitamin D combination therapy group. Change in serum 25(OH)D level from baseline to week 16 was higher in the raloxifene/vitamin D combination therapy group (2.7±6.5 ng/mL) than in the raloxifene monotherapy (−1.7±6.2 ng/mL; P=0.0034) group. Proportions and number of adverse events (AEs) categorized by the System-Organ Class were not different between the groups. There was only one severe AE case (spondylolisthesis; raloxifene/vitamin D group), unlikely to be related to trial intervention.

Conclusions

Among postmenopausal women with osteoporosis or osteopenia, a fixed dose combination of raloxifene 60 mg/vitamin D 800 IU showed superior efficacy in elevating serum 25(OH)D levels compared with raloxifene 60 mg alone during 16 weeks of follow-up. The safety of raloxifene/vitamin D combination was comparable to raloxifene alone.

Characterization of raloxifene as a potential pharmacological agent against SARS-CoV-2 and its variants

The new coronavirus SARS-CoV-2 is the causative agent of the COVID-19 pandemic, which so far has caused over 6 million deaths in 2 years, despite new vaccines and antiviral medications. Drug repurposing, an approach for the potential application of existing pharmaceutical products to new therapeutic indications, could be an effective strategy to obtain quick answers to medical emergencies. Following a virtual screening campaign on the most relevant viral proteins, we identified the drug raloxifene, a known Selective Estrogen Receptor Modulator (SERM), as a new potential agent to treat mild-to-moderate COVID-19 patients. In this paper we report a comprehensive pharmacological characterization of raloxifene in relevant in vitro models of COVID-19, specifically in Vero E6 and Calu-3 cell lines infected with SARS-CoV-2. A large panel of the most common SARS-CoV-2 variants isolated in Europe, United Kingdom, Brazil, South Africa and India was tested to demonstrate the drug's ability in contrasting the viral cytopathic effect (CPE). Literature data support a beneficial effect by raloxifene against the viral infection due to its ability to interact with viral proteins and activate protective estrogen receptor-mediated mechanisms in the host cells. Mechanistic studies here reported confirm the significant affinity of raloxifene for the Spike protein, as predicted by in silico studies, and show that the drug treatment does not directly affect Spike/ACE2 interaction or viral internalization in infected cell lines. Interestingly, raloxifene can counteract Spike-mediated ADAM17 activation in human pulmonary cells, thus providing new insights on its mechanism of action. A clinical study in mild to moderate COVID-19 patients (NCT05172050) has been recently completed. Our contribution to evaluate raloxifene results on SARS-CoV-2 variants, and the interpretation of the mechanisms of action will be key elements to better understand the trial results, and to design new clinical studies aiming to evaluate the potential development of raloxifene in this indication.

Phenols in Pharmaceuticals: Analysis of a Recurring Motif

Phenols and phenolic ethers are significant scaffolds recurring both in nature and among approved small-molecule pharmaceuticals. This compendium presents the first comprehensive compilation and analysis of the structures of U.S. FDA-approved molecules containing phenol or phenolic ether fragments. This dataset comprises 371 structures, which are strongly represented by natural products. A total of 55 of the compounds described here are on the World Health Organization's list of essential medicines. Structural analysis reveals significant differences in the physicochemical properties imparted by phenols versus phenol ethers, each having benefits and drawbacks for drug developability. Despite trends over the past decade to increase the fraction of sp³ centers in drug leads, thereby "escaping flatland", phenols and phenolic ethers are represented in 62% of small-molecule drugs approved in 2020, suggesting that this aromatic moiety holds a special place in drugs and natural products.

Pharmacokinetic Drug Interaction Between Raloxifene and Cholecalciferol in Healthy Volunteers

Osteoporosis is a common skeletal disorder, often leading to fragility fracture. Combination therapy with raloxifene, a selective estrogen receptor modulator, and cholecalciferol (vitamin D₃) has been proposed to improve the overall efficacy and increase compliance of raloxifene therapy for postmenopausal osteoporosis. To our knowledge, there has been no report of any study on the pharmacokinetic interaction between raloxifene and cholecalciferol. This study aimed to evaluate the possible pharmacokinetic interactions between raloxifene and cholecalciferol in healthy adult male Korean volunteers. Twenty subjects completed this open‐label, randomized, single‐dose, 3‐period, 6‐sequence, crossover phase 1 study with a 14‐day washout period. Serial blood samples were collected from 20 hours before dosing to 96 hours after dosing. The plasma concentrations of raloxifene and cholecalciferol were determined using a validated method for high‐performance liquid chromatography with tandem mass spectrometry. The geometric mean ratios (90%CIs) for area under the plasma concentration–time curve from time 0 to the last quantifiable time point and maximum plasma concentration of raloxifene with or without cholecalciferol were 1.02 (0.87‐1.20) and 0.87 (0.70‐1.08), respectively. For baseline‐corrected cholecalciferol, geometric mean ratios (90%CIs) of area under the plasma concentration–time curve from time 0 to the last quantifiable time point and maximum plasma concentration with or without raloxifene were 1.01 (0.93‐1.09) and 0.99 (0.92‐1.06), respectively. Concurrent treatment with raloxifene and cholecalciferol was generally well tolerated. These results suggest that raloxifene and cholecalciferol have no clinically relevant pharmacokinetic drug‐drug interactions when administered concurrently. All treatments were well tolerated, with no serious adverse events.

Structure-based design and synthesis of conformationally constrained derivatives of methyl-piperidinopyrazole (MPP) with estrogen receptor (ER) antagonist activity

Nuclear Estrogen receptors (ER) are cytoplasmic proteins; translocated to the nucleus to induce transcriptional signals after getting bound to the estrogen hormone. ER activation implicated in cancer cell proliferation of female reproductive organs. Thus, the discovery of ER antagonists is a reliable strategy to combat estrogen-dependent breast cancer. Endometrial carcinoma is one of the complications encountered upon long-term therapy by selective estrogen receptor modulators (SERMs) like Tamoxifen (TMX) and methyl piperidinopyrazole (MPP). Thus, the ER-full antagonist is a solution to improve the safety of this class of therapeutics during the treatment of breast cancer. We selected MPP as a lead structure to design conformationally constrained analogs. Structural rigidification is a proven strategy to transform the SERMs into full antagonists. Accordingly, we synthesized 7-methoxy-3-(4-methoxyphenyl)-4,5-dihydro-2H-benzo[g]indazoles (4), (6a-c),(8-12) along with the biphenolic counterparts(13-19)that are the anticipated active metabolites. The 4-nitrophenyl derivative(4)is with the most balanced profile regardingthe in vivoanti-uterotrophic potential (EC₅₀ = 4.160 μM); and the cytotoxicity assay of the corresponding active metabolite(13)against ER+ breast cancer cell lines (MCF-7 IC₅₀ = 7.200 μM, T-47D IC₅₀ = 11.710 μM). The inconsiderable uterotrophic activities of the elaborated ER-antagonists and weak antiproliferative activity of the compound(13)against ovarian cancer (SKOV-3 IC₅₀ = 29.800 μM) highlighted it as a good start point to elaborate potential ER-full antagonists devoid of endometrial carcinoma. Extending the pendant chain that protrudes from the 2-(4-(substituted)-phenyl) ring of the new benzo-indazoles is recommended for enhancing the potency based on the binding mode of compound(13)in the ligand-binding domain (LBD) of ER.

Chiral Benzothiophene Synthesis via Enantiospecific Coupling of Benzothiophene S-Oxides with Boronic Esters

Benzothiophenes are valuable heterocycles that are widely used in medicines, agrochemicals, and materials science. Herein, we report a general method for the synthesis of enantioenriched 2,3-disubstituted benzothiophenes via a transition-metal-free C2-alkylation of benzothiophenes with boronic esters. The reactions utilize benzothiophene S-oxides in lithiation-borylations to generate intermediate arylboronate complexes, and subsequent Tf₂ O-promoted S-O bond cleavage to trigger a Pummerer-type 1,2-metalate shift, which gives the coupled products with complete enantiospecificity. Primary, secondary and tertiary alkyl boronic esters and aryl boronic esters are successfully coupled with a range of C3-substituted benzothiophenes. Importantly, this transformation does not require the use of C3 directing groups, therefore it overcomes a major limitation of previously developed transition-metal-mediated C2 alkylations of benzothiophenes.

Identification of raloxifene as a novel α-glucosidase inhibitor using a systematic drug repurposing approach in combination with cross molecular docking-based virtual screening and experimental verification

α-Glucosidase is a promising target for the treatment of diabetes. Drug repurposing can increase the chances of discovering an active inhibitor. Therefore, this study aimed to identify potential α-glucosidase inhibitor using drug repurposing and in silico strategies. We identified critical amino acid residues of the three α-glucosidase proteins. Based on cross molecular docking studies of three α-glucosidase proteins and drugs in the FDA database, we screened hits with the favorable binding affinities and modes targeting the three proteins. Subsequently, an in vitro activity assay showed that raloxifene was an excellent inhibitor of α-glucosidase. Moreover, molecular dynamics simulations of raloxifene and three proteins were performed to assess the stability of the protein-hit systems in physiological conditions and clarify protein-hit interactions. We also performed the binding free energy calculation, Hirshfeld surface and alanine scanning mutagenesis analyses. These results demonstrated that binding between raloxifene and the three proteins was stable, and the critical amino acid residues of the three proteins formed stable contacts with raloxifene. The molecular mechanisms agree well with its activity, reinforcing that raloxifene is a candidate α-glucosidase inhibitor. Our study smoothes the path for the development of novel a-glucosidase inhibitors with high efficacy and low toxicity for the treatment of diabetes.

The Effect of Raloxifene Treatment on Lipid Profile in Elderly Individuals: A Systematic Review and Meta-analysis of Randomized Clinical Trials

PURPOSE

To perform a systematic review and meta-analysis of randomized clinical trials (RCTs) to elucidate the effects of raloxifene on the lipid profile in elderly individuals.

METHODS

A systematic review and meta-analysis of RCTs was performed following the PRISMA statement. Data on triglycerides (TGs), total cholesterol (TC), HDL-C, and LDL-C were extracted. Relevant publications up to October 2020 were detected through searches in the PubMed/MEDLINE, Web of Science, Scopus, and Embase databases. Changes were reported as weighted mean differences (WMDs) and 95% CIs using random-effects models.

FINDINGS

Nine studies were selected, with a duration of intervention ranging from 2 and 12 months and a raloxifene dose of 60 to 120 mg/d. Studies were performed in healthy individuals and in those with disorders, such as osteoporosis, type 2 diabetes, and kidney disease required long-term hemodialysis. Overall, TG (WMD, -6.50 mg/dL; 95% CI, -34.18 to 21.20 mg/eL; P = 0.646), LDL-C (WMD, -17.86 mg/dL; 95% CI, -42.44 to 6.72 mg/dL; P = 0.154), and HDL-C (WMD, 2.35 mg/dL; 95% CI, -1.14 to 5.84 mg/dL; P = 0.187) levels did not change significantly after the administration of raloxifene. In contrast, TC levels decreased after raloxifene therapy (WMD, -6.59 mg/dL; 95% CI, -13.13 to -0.05 mg/dL; P = 0.048).

IMPLICATIONS

Raloxifene therapy decreased TC levels but did not alter TG, HDL-C, and LDL-C concentrations in elderly individuals. Regarding the LDL-C levels, although the finding lacked statistical significance, we believe that there was a mean reduction that deserves further clinical attention as much as TC.

Expedition of sulfur-containing heterocyclic derivatives as cytotoxic agents in medicinal chemistry: A decade update

This review article proposes a comprehensive report of the design strategies engaged in the development of various sulfur-bearing cytotoxic agents. The outcomes of various studies depict that the sulfur heterocyclic framework is a fundamental structure in diverse synthetic analogs representing a myriad scope of therapeutic activities. A number of five-, six- and seven-membered sulfur-containing heterocyclic scaffolds, such as thiazoles, thiadiazoles, thiazolidinediones, thiophenes, thiopyrans, benzothiazoles, benzothiophenes, thienopyrimidines, simple and modified phenothiazines, and thiazepines have been discussed. The subsequent studies of the derivatives unveiled their cytotoxic effects through multiple mechanisms (viz. inhibition of tyrosine kinases, topoisomerase I and II, tubulin, COX, DNA synthesis, and PI3K/Akt and Raf/MEK/ERK signaling pathways), and several others. Thus, our concise illustration explains the design strategy and anticancer potential of these five- and six-membered sulfur-containing heterocyclic molecules along with a brief outline on seven-membered sulfur heterocycles. The thorough assessment of antiproliferative activities with the reference drug allows a proficient assessment of the structure-activity relationships (SARs) of the diversely synthesized molecules of the series.

Construction of a TF-miRNA-gene feed-forward loop network predicts biomarkers and potential drugs for myasthenia gravis

Myasthenia gravis (MG) is an autoimmune disease and the most common type of neuromuscular disease. Genes and miRNAs associated with MG have been widely studied; however, the molecular mechanisms of transcription factors (TFs) and the relationship among them remain unclear. A TF–miRNA–gene network (TMGN) of MG was constructed by extracting six regulatory pairs (TF–miRNA, miRNA–gene, TF–gene, miRNA–TF, gene–gene and miRNA–miRNA). Then, 3/4/5-node regulatory motifs were detected in the TMGN. Then, the motifs with the highest Z-score, occurring as 3/4/5-node composite feed-forward loops (FFLs), were selected as statistically significant motifs. By merging these motifs together, we constructed a 3/4/5-node composite FFL motif-specific subnetwork (CFMSN). Then, pathway and GO enrichment analyses were performed to further elucidate the mechanism of MG. In addition, the genes, TFs and miRNAs in the CFMSN were also utilized to identify potential drugs. Five related genes, 3 TFs and 13 miRNAs, were extracted from the CFMSN. As the most important TF in the CFMSN, MYC was inferred to play a critical role in MG. Pathway enrichment analysis showed that the genes and miRNAs in the CFMSN were mainly enriched in pathways related to cancer and infections. Furthermore, 21 drugs were identified through the CFMSN, of which estradiol, estramustine, raloxifene and tamoxifen have the potential to be novel drugs to treat MG. The present study provides MG-related TFs by constructing the CFMSN for further experimental studies and provides a novel perspective for new biomarkers and potential drugs for MG.

Raloxifene as a treatment option for viral infections

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused corona virus disease 2019 (COVID-19) pandemic and led to mass casualty. Even though much effort has been put into development of vaccine and treatment methods to combat COVID-19, no safe and efficient cure has been discovered. Drug repurposing or drug repositioning which is a process of investigating pre-existing drug candidates for novel applications outside their original medical indication can speed up the drug development process. Raloxifene is a selective estrogen receptor modulator (SERM) that has been approved by FDA in 1997 for treatment and prevention of postmenopausal osteoporosis and cancer. Recently, raloxifene demonstrates efficacy in treating viral infections by Ebola, influenza A, and hepatitis C viruses and shows potential for drug repurposing for the treatment of SARS-CoV-2 infection. This review will provide an overview of raloxifene's mechanism of action as a SERM and present proposed mechanisms of action in treatment of viral infections.

Recent Progress in the Synthesis of Benzo[b]thiophene

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Due to such a wide range of applicability, the synthesis of benzo[b]thiophene derivatives has attracted intensive research. Numerous mild and efficient approaches for the synthesis of benzo[b]thiophenes have been developed over the years. Different catalysts and substrates have been applied for benzo[b]thiophene synthesis. This review will focus on the studies in the construction of benzo[b]thiophene skeleton, which date back from 2012.

Hormone therapy for first-line management of menopausal symptoms: Practical recommendations

Hormone therapy use has undergone dramatic changes over the past 20 years. Widespread use of hormone therapy in the 1980s and 1990s came to an abrupt halt in the early 2000s after initial findings of the Women’s Health Initiative trial were published and the study was terminated. Since then, much has been learned about the characteristics of women most likely to benefit from hormone therapy. There is general agreement that women younger than 60 years or who initiate hormone therapy within 10 years of menopause onset gain short-term benefit in terms of symptomatic relief and long-term benefit in terms of protection from chronic diseases that affect postmenopausal women. Despite accumulating evidence in support of hormone therapy for symptomatic menopausal women, the slow response by the medical community has led to a ‘large and unnecessary burden of suffering’ by women worldwide. Greater efforts are clearly needed to educate physicians and medical students about the pathophysiology of menopause and the role of hormone therapy in supporting women through the transition. This article provides a brief historical perspective of events that led to the backlash against hormone therapy, explores the current position of guideline groups, and provides practical recommendations to guide first-line management of symptomatic menopausal women.

Influence of Supplementary Vitamin D on Bone Mineral Density When Used in Combination with Selective Estrogen Receptor Modulators

Objectives

Vitamin D is regarded as one of the major nutrients that significantly influence bone metabolism. This study aims to look at the effect of supplementary vitamin D on bone mineral density (BMD) in female osteoporosis patients.

Methods

The retrospective hospital record review was performed on 282 patients who were diagnosed with osteoporosis and treated with selective estrogen receptor modulators (SERMs) between January 2015 and December 2016. Of these patients, 151 were treated with SERMs only while 131 were treated using both SERMs and vitamin D supplements. The BMD and any occurrence of osteoporotic fracture episode were investigated after one year. The result of two groups was compared to find the significance of vitamin D.

Results

Overall, improvement in BMD score was observed in 76% of the patients. The BMD of the SERMs only group improved by 3% in spine and 1% in the hip while that of the SERMs with vitamin D group improved by 6% and 1% respectively. Statistical significance was noticed in the spine only. One distal radius fracture and one single level vertebral fracture occurred in patients of SERMs group while two distal radius fractures occurred in SERMs with vitamin D group. There was no occurrence of around hip fracture in both groups.

Conclusion

The result of the current study suggests that additional vitamin D may have some additive effect on improving BMD of the spine. Further study with the larger study population and the extended study period is recommended.

Targeting hypothalamic-pituitary-adrenal axis hormones and sex steroids for improving cognition in major mood disorders and schizophrenia: a systematic review and narrative synthesis

Cognitive deficits are a core feature of serious mental illnesses such as schizophrenia, major depressive disorder (MDD) and bipolar disorder (BD) and are a common cause of functional disability. There is limited efficacy of pharmacological interventions for improving the cognitive deficits in these disorders. As pro-cognitive pharmacological treatments are lacking, hormones or drugs that target the endocrine system may become potential candidates for 'repurposing' trials aiming to improve cognition. We aimed to study whether treatment with drugs targeting the hypothalamic-pituitary-adrenal (HPA) axis and sex steroids can improve cognition in patients with schizophrenia, MDD or BD. A systematic search was performed using PubMed (Medline), PsychInfo and clinicaltrials.gov, and a narrative synthesis was included. The systematic review identified 12 studies dealing with HPA-related drugs (mifepristone [n = 3], cortisol synthesis inhibitors [ketoconazole, n = 2], dehydroepiandrosterone [n = 5], fludrocortisone [n = 2]) and 14 studies dealing with sex steroids (oestradiol [n = 2], selective oestrogen receptor modulators [raloxifene, n = 7], pregnenolone [n = 5]). Positive trials were found for BD (mifepristone), MDD (dehydroepiandrosterone and fludrocortisone) and schizophrenia (dehydroepiandrosterone, raloxifene and pregnenolone). A replication of positive findings by at least two clinical trials was found for mifepristone in BD and raloxifene and pregnenolone in schizophrenia. The use of drugs targeting hormones related to the HPA axis and sex steroids is a promising field of research that might help to improve the cognitive outcome of patients with schizophrenia, bipolar disorder and major depressive disorder in the near future.

Protective effect of Rhizoma Dioscoreae extract against alveolar bone loss in ovariectomized rats via regulation of IL-6/STAT3 signaling

The aim of the present study was to assess the effectiveness of Rhizoma Dioscoreae extract (RDE) on preventing rat alveolar bone loss induced by ovariectomy (OVX), and to determine the role of interleukin-6 (IL-6)/signal transducer and activator of transcription 3 (STAT3) signaling pathway in this effect. Female Wistar rats were subjected to OVX or sham surgery. The rats that had undergone OVX were treated with RDE (RDE group), vehicle (OVX group) or 17β-estradiol subcutaneous injection (E2 group). Subsequently, bone metabolic activity was assessed by analyzing 3-D alveolar bone construction, bone mineral density, as well as the plasma biomarkers of bone turnover. The gene expression of alveolar bone in the OVX and RDE groups was evaluated by IL-6/STAT3 signaling pathway polymerase chain reaction (PCR) arrays, and differentially expressed genes were determined through reverse transcription-quantitative PCR. The inhibitory effect of RDE on alveolar bone loss in the OVX group was demonstrated in the study. In comparison with the OVX group, the RDE group exhibited 19 downregulated genes and 1 upregulated gene associated with the IL-6/STAT3 signaling pathway in alveolar bone. Thus, RDE was shown to relieve OVX-induced alveolar bone loss in rats, an effect which was likely associated with decreased abnormal bone remodeling via regulation of the IL-6/STAT3 signaling pathway.

Drug repurposing in cancer

Cancer is a major health issue worldwide, and the global burden of cancer is expected to increase in the coming years. Whereas the limited success with current therapies has driven huge investments into drug development, the average number of FDA approvals per year has declined since the 1990s. This unmet need for more effective anti-cancer drugs has sparked a growing interest for drug repurposing, i.e. using drugs already approved for other indications to treat cancer. As such, data both from pre-clinical experiments, clinical trials and observational studies have demonstrated anti-tumor efficacy for compounds within a wide range of drug classes other than cancer. Whereas some of them induce cancer cell death or suppress various aspects of cancer cell behavior in established tumors, others may prevent cancer development. Here, we provide an overview of promising candidates for drug repurposing in cancer, as well as studies describing the biological mechanisms underlying their anti-neoplastic effects.

Raloxifene Administration in Women Treated with Long Term Gonadotropin-releasing Hormone Agonist for Severe Endometriosis: Effects on Bone Mineral Density

Objectives

To evaluate the efficacy of raloxifene in preventing bone loss associated with long term gonadotropin-releasing hormone agonist (GnRH-a) administration.

Methods

Twenty-two premenopausal women with severe endometriosis were treated with leuprolide acetate depot at a dosage of 3.75 mg/4 weeks, for 48 weeks. Bone mineral density (BMD) was evaluated at admission, and after 12 treatment cycles.

Results

At cycle 12 of GnRH-a plus raloxifene treatment, lumbar spine, trochanter femoral neck, and Ward's BMD differed from before the treatment. A year after treatment, the lumbar spine and trochanter decreased slightly, but were not significantly different.

Conclusions

Our study shows that the administration of GnRH-a plus raloxifene in pre-menopausal women with severe endometriosis, is an effective long-term treatment to prevent bone loss.

Raloxifene: A Selective Estrogen Receptor Modulator for Reducing the Risk of Invasive Breast Cancer in Postmenopausal Women

Raloxifene hydrochloride is a selective estrogen receptor modulator that has antiestrogenic effects on breast and endometrial tissue and estrogenic effects on bone, lipid metabolism and blood clotting. Tamoxifen is the prototypical selective estrogen receptor modulator and reduces the risk of both in situ and invasive breast cancers by half when compared with placebo. The limitations on the use of tamoxifen for breast cancer risk reduction relate to its well-known, but rare, side effects. A number of clinical trials have established the benefit of raloxifene on osteoporosis and fracture. Raloxifene significantly improves serum lipids and serum markers of cardiovascular disease risk, but has no significant effect on the risk of primary coronary events. In several osteoporosis trials and the Raloxifene Use for The Heart (RUTH) trial, raloxifene decreased the risk of estrogen receptor-positive breast cancer by 44–90%. In the Study of Tamoxifen And Raloxifene (STAR) trial, the effect of raloxifene on invasive breast cancer was equivalent to that of tamoxifen, with more favorable effects on uterine malignancy and clotting events. Symptomatic side effects are acceptable. In total, the available data indicate that raloxifene represents an acceptable alternative to tamoxifen for the reduction of the risk of postmenopausal breast cancer in high-risk women. The potential market for a compound shown to reduce the risk of breast cancer in postmenopausal women who are at increased risk for breast cancer is more than 10 million women in the USA alone.

Antiosteoporotic effects of Alpinia officinarum Hance through stimulation of osteoblasts associated with antioxidant effects

BACKGROUND/OBJECTIVE

Alpinia officinarum Hance (AOH) is a traditional herbal medicine specific to south China and serves as a civil medication application of an antioxidant. Growing evidence demonstrates that antioxidants are beneficial for the treatment of osteoporosis. This study was designed to investigate the antiosteoporotic effects of total extracts from AOH in ovariectomised (OVX) rats and the different fractions in AOH on primary osteoblasts activities.

METHODS

The total extract of AOH was extracted by refluxing using 95% ethanol, then the five fractions (F1-F5) were separated from AOH using thin-layer chromatography according to polarity from high to low, and the galangin content was determined using high performance liquid chromatography. In an in vivo study, 36 4-month-old female Sprague-Dawley rats were used as a Sham-operated group, OVX with vehicle (OVX), OVX with epimedium flavonoids (EF, 150 mg/kg/d), and OVX with AOH (AOH, 300 mg/kg/d), respectively. Daily oral administration started on Day 3 after OVX and lasted for 12 weeks. In the in vitro study, primary osteoblasts were incubated with AOH, galangin, and five different fractions (F1-F5) with or without hydrogen peroxide (H2O2), respectively.

RESULTS

Treatment with AOH significantly attenuated osteopenia accompanied by a decreased percentage of osteoclast perimeter and bone formation rate per unit of bone surface, enhanced the bone strength, and prevented the deterioration of trabecular microarchitecture associated with a decrease in biochemical parameters of oxidative stress. Furthermore, treatment with AOH, F3, F4, and galangin increased cell viability, differentiation, and mineralisation in osteoblasts with or without H2O2 and rescued the deleterious effects of H2O2 on cell apoptosis and intracellular reactive oxygen species level. The effects on osteoblast formation were highly aligned with the amounts of flavonoids within AOH.

CONCLUSION

These data demonstrate that ethanol extracts from AOH significantly reverse bone loss, partially by increasing bone formation, and by suppressing bone resorption associated with antioxidant effects, suggesting that AOH can be developed as a promising agent for the prevention and treatment of osteoporosis.

The challenges for cancer chemoprevention

The incidence of cancer is rising in parallel with an ageing populous thus increasing the strain on both treatment options and budgets for healthcare providers worldwide. New cancer therapies are being developed but at what cost? The new treatments are expensive and poor survival rates still exist for some cancers. What is needed now is to prevent or at least limit the disease occurring in the first place. This review evaluates the current situation and the progress in upcoming strategies as well as suggesting some areas for further research within the increasingly important field of cancer chemoprevention. The key principles of cancer chemoprevention are discussed and areas for improvement highlighted. Despite significant progress, chemoprevention has not been widely adopted. Cancer chemoprevention has many challenges to face but this only emphasises the size of the task. These hurdles include a lack of awareness of the benefits, a lack of interest and a lack of investment in taking prevention forward. Despite the huge potential importance of cancer prevention and clinical success stories such as the well-publicised HPV vaccine, the challenges remain significant. With cancer and its treatment being a global issue, the opportunities offered by chemoprevention must be re-evaluated and uptake of chemoprevention actively encouraged. If chemoprevention is to be adopted successfully, a holistic approach is required. This approach will involve multidisciplinary teams of healthcare providers and scientists with the big challenge particularly for medicinal chemists being to design and synthesise the ideal chemopreventative agent.

Synthesis and biological evaluation of novel m-carborane-containing estrogen receptor partial agonists as SERM candidates

We designed and synthesized novel m-carborane-containing selective estrogen receptor modulator (SERM) candidates using previously reported m-carborane-containing ER partial agonist 1 as the lead compound. Biological activities were evaluated by means of ERα competitive binding assay and MCF-7 cell proliferation assay. Re-positioning the N,N-dimethylaminoethyloxy group at the para position of 1 to the meta position enhanced the ERα-binding affinity, and 4c showed the highest relative binding affinity (RBA: 83 vs 17β-estradiol = 100) among the tested compounds. Compound 4b showed the most potent ER-agonist activity (EC50: 1.4 nM) and the lowest maximal efficacy (Emax: 50%) in MCF-7 cell proliferation assay. Inhibition of 0.1 nM 17β-estradiol-induced MCF-7 cell proliferation by 4b (IC50: 0.4 μM) was at least 10 times more potent than that of the lead compound 1.

The protective effect of Rhizoma Dioscoreae extract against alveolar bone loss in ovariectomized rats via regulating Wnt and p38 MAPK signaling

AIM

The aim of this study was to evaluate the osteoprotective effect of aqueous Rhizoma Dioscoreae extract (RDE) on the alveolar bone of rats with ovariectomy-induced bone loss.

METHODS

Female Wistar rats were subjected to either ovariectomy or a sham operation (SHAM). The ovariectomized (OVX) rats were treated with vehicle (OVX) or RDE by oral gavage or with 17β-estradiol (E2) subcutaneously. After treatments, the bone mineral density (BMD), the three-dimensional bone architecture of the alveolar bone and the plasma biomarkers of bone turnover were analyzed to assess bone metabolism, and the histomorphometry of the alveolar bone was observed. Microarrays were used to evaluate gene expression profiles in alveolar bone from RDE-treated and OVX rats. The differential expression of genes was further analyzed using Ingenuity Pathway Analysis (IPA). The key findings were verified using real-time quantitative RT-PCR (qRT-PCR).

RESULTS

Our results showed that RDE inhibited alveolar bone loss in OVX rats. Compared to the OVX rats, the RDE-treated rats showed upregulated expression levels of 207 genes and downregulated expression levels of 176 genes in the alveolar bone. The IPA showed that several genes had the potential to code for proteins that were involved in the Wnt/β-catenin signaling pathway (Wnt7a, Fzd2, Tcf3, Spp1, Frzb, Sfrp2 and Sfrp4) and the p38 MAPK signaling pathway (Il1rn and Mapk14).

CONCLUSION

These experiments revealed that RDE could inhibit ovariectomy-induced alveolar bone loss in rats. The mechanism of this anti-osteopenic effect in alveolar bone may be involved in the reduced abnormal bone remodeling, which is associated with the modulation of the Wnt/β-catenin and the p38 MAPK signaling pathways via gene regulation.

High-dose diosgenin reduces bone loss in ovariectomized rats via attenuation of the RANKL/OPG ratio

The aim of this study was to evaluate effect of diosgenin (DG) on rats that had osteoporosis-like features induced by ovariectomy (OVX). Seventy-two six-month-old female Wistar rats were subjected to either ovariectomy (n = 60) or Sham operation (SHAM group, n = 12). Beginning at one week post-ovariectomy, the OVX rats were treated with vehicle (OVX group, n = 12), estradiol valerate (EV group, n = 12), or DG at three doses (DG-L, -M, -H group, n = 12, respectively). After a 12-week treatment, administration of EV or DG-H inhibited OVX-induced weight gain, and administration of EV or DG-H or DG-M had a significantly uterotrophic effect. Bone mineral density (BMD) and indices of bone histomorphometry of tibia were measured. Levels of protein and mRNA expression of osteoprotegerin (OPG) and receptor activator of nuclear factor kappa-B ligand (RANKL) in tibia were evaluated by immunohistochemistry and in situ hybridization. Our results show that DG at a high dose (DG-H) had a significant anti-osteoporotic effect compared to OVX control. DG-H treatment down-regulated expression of RANKL and up-regulated expression of OPG significantly in tibia from OVX rats compared to control, and thus lowered the RANKL/OPG ratio. This suggests that the anti-osteoporotic effect of DG might be associated with modulating the RANKL/OPG ratio and DG had potential to be developed as alternative therapeutic agents of osteoporosis induced by postmenopause.

Contemporary pharmacotherapy for the prevention of skeletal complications in patients with prostate cancer

INTRODUCTION

Bones represent the most common metastatic sites in prostate cancer (PCa) patients, and in addition with androgen deprivation therapy, they represent the causative reasons of bone mineral density loss and the onset of skeletal-related events.

AREAS COVERED

An extensive search of PubMed/Medline was performed to identify randomized, Phase II/III controlled trials reporting results regarding the prevention of skeletal morbidity in patients with PCa.

EXPERT OPINION

Preventing bone health is an imperative issue for preserving quality of life and elongate survival and, thus, a concerted effort should be made to monitor skeletal changes and to apply treatment for preventing bone loss. Although several agents have received approval for routine use, it is of paramount importance to identify the appropriate patients who would mostly be benefited by the use of these agents with attention to documenting the toxicity and economic implications. Additionally, it remains to be justified the frequency of administration in order to balance the efficacy and the potential complications.

An overview of current and emerging SERMs

Selective estrogen receptor modulators (SERMs) are compounds that exhibit tissue-specific estrogen receptor (ER) agonist or antagonist activity, and are used for various indications, including treatment of breast cancer, osteoporosis, and menopausal symptoms. Endometrial safety has been a key differentiator between SERMs in clinical practice. For example, tamoxifen exhibits ER agonist activity in the uterus, resulting in an increased risk of endometrial hyperplasia and malignancy, whereas raloxifene and bazedoxifene have neutral effects on the uterus. Based on their efficacy and long-term safety, SERMs are increasingly being prescribed for women who cannot tolerate other treatment options and for younger women at an increased risk of fracture who may remain on therapy for long periods of time. Continuing advances in the understanding of SERM mechanisms of action and structural interactions with the ER may lead to the development of new agents and combinations of agents to provide optimal treatments to meet the varying needs of postmenopausal women. One such example is the tissue selective estrogen complex, which partners a SERM with 1 or more estrogens, with the aim of blending the desired estrogen-receptor agonist activities of estrogens on vasomotor symptoms, vulvar-vaginal atrophy, and loss of bone mass with the tissue selectivity of a SERM.

Mechanism of raloxifene-induced upregulation of glutamate transporters in rat primary astrocytes

Raloxifene (RX), a selective estrogen receptor modulator (SERM), exerts neuroprotection in multiple clinical and experimental settings. Astrocytic glutamate transporters GLT-1 (EAAT2) and GLAST (EAAT1) are the main glutamate transporters in the central nervous system, taking up most of excess glutamate from the synaptic cleft to prevent excitotoxic neuronal death. Since drugs targeting astrocytic glutamate transporters to enhance their expression and function represent potential therapeutics for neurodegenerative disorders associated with excitotoxicity, we tested if RX modulates the expression and function of GLT-1 and GLAST in rat primary astrocytes. The results showed that RX significantly increased glutamate uptake and expression of GLT-1 mRNA and protein levels. RX enhanced GLT-1 expression by the activation of multiple signaling pathways including ERK, EGFR, and CREB mediated by estrogen receptors (ERs) ER-α, ER-β, and GPR30. At the transcriptional level, NF-κB played a critical role in RX-induced GLT-1 expression as RX increased NF-κB reporter activity and induced binding of NF-κB p65 and p50 to the GLT-1 promoter. RX attenuated the reduction of GLT-1 expression and glutamate uptake induced by manganese (Mn) whose chronic high levels of exposure cause manganism. RX also upregulated GLAST by increasing its promoter activity and protein levels via the NF-κB pathway and ERs. Our findings provide new insight into the mechanism of RX-induced enhancement of GLT-1 and GLAST expression, as well as the attenuation of Mn-reduced expression of these transporters. These findings will be highly valuable for developing therapeutics of neurodegenerative diseases associated with impaired astrocytic glutamate transporters.

Treatment with Rhizoma Dioscoreae extract has protective effect on osteopenia in ovariectomized rats

The aims of this study were to evaluate the osteoprotective effect of aqueous extract from Rhizoma Dioscoreae (RDE) on rats with ovariectomy- (OVX-) induced osteopenia. Our results show that RDE could inhibit bone loss of OVX rats after a 12-week treatment. The microarray analysis showed that 68 genes were upregulated and that 100 genes were downregulated in femurs of the RDE group rats compared to those in the OVX group. The Ingenuity Pathway Analysis (IPA) showed that several downregulated genes had the potential to code for proteins that were involved in the Wnt/ β -catenin signaling pathway (Sost, Lrp6, Tcf7l2, and Alpl) and the RANKL/RANK signaling pathway (Map2k6 and Nfatc4). These results revealed that the mechanism for an antiosteopenic effect of RDE might lie in the synchronous inhibitory effects on both the bone formation and the bone resorption, which is associated with modulating the Wnt/ β -catenin signaling and the RANKL/RANK signaling.

Nuclear receptors and their selective pharmacologic modulators

Nuclear receptors are ligand-activated transcription factors and include the receptors for steroid hormones, lipophilic vitamins, sterols, and bile acids. These receptors serve as targets for development of myriad drugs that target a range of disorders. Classically defined ligands that bind to the ligand-binding domain of nuclear receptors, whether they are endogenous or synthetic, either activate receptor activity (agonists) or block activation (antagonists) and due to the ability to alter activity of the receptors are often termed receptor "modulators." The complex pharmacology of nuclear receptors has provided a class of ligands distinct from these simple modulators where ligands display agonist/partial agonist/antagonist function in a tissue or gene selective manner. This class of ligands is defined as selective modulators. Here, we review the development and pharmacology of a range of selective nuclear receptor modulators.

Adverse drug reactions to osteoporosis treatments

Treatments for postmenopausal osteoporosis are generally safe, but are linked to some rare serious adverse drug reactions, for which causality is not always certain. The bisphosphonates are associated with gastrointestinal effects, acute phase reactions, and musculoskeletal pain, and, more rarely, cases of atrial fibrillation, subtrochanteric fracture, osteonecrosis of the jaw, cutaneous hypersensitivity reactions and renal impairment. It is too soon for pharmacovigilance data on denosumab, but it has been associated with cutaneous effects and possibly osteonecrosis of the jaw (to date, only in metastatic cancer). The selective estrogen receptor modulators may induce hot flushes and leg cramps, and--more rarely--venous thromboembolism and stroke. Strontium ranelate is associated with headache, nausea and diarrhea, and, more rarely, cutaneous hypersensitivity reactions and venous thromboembolism, while teriparatide and parathyroid hormone(1-84) are associated with headache, nausea, dizziness and limb pain. The management of osteoporosis should entail weighing the probability of adverse reactions against the benefits of therapy--that is, reduction of fracture risk.

Ormeloxifene inhibits osteoclast differentiation in parallel to downregulating RANKL-induced ROS generation and suppressing the activation of ERK and JNK in murine RAW264.7 cells

Ormeloxifene (Orm), a triphenylethylene compound, has been established as a selective estrogen receptor modulator (SERM) that suppresses the ovariectomy-induced bone resorption in rats. However, the precise mechanism underlying the bone-preserving action of Orm remains unclear. In this study, we evaluated the effect of Orm on osteoclast formation induced by receptor activator of nuclear factor κB ligand (RANKL) in the murine macrophage cell line RAW264.7. We also explored the mechanism of action of Orm by studying the RANKL-induced signaling pathways required for osteoclast differentiation. We found that Orm inhibited osteoclast formation from murine macrophage RAW264.7 cells induced by RANKL in a dose-dependent manner. Orm was able to abolish RANKL-induced reactive oxygen species (ROS) elevation and inhibited the transcriptional activation of two key RANKL-induced transcription factors namely activator protein-1 (AP-1) and NF-κB through mechanisms involving MAPKs. Activation of two MAPKs, i.e. ERK (MAPK1) and JNK (MAPK8), was alleviated by Orm effectively, which subsequently affected the activation of c-Jun and c-Fos, which are the essential components of the AP-1 transcription complex. Taken together, our results demonstrate that Orm potentially inhibits osteoclastogenesis by inhibiting ROS generation and thereby suppressing the activation of ERK1/2 (MAPK3/MAPK1) and JNK (MAPK8) and transcription factors (NF-κB and AP-1), which subsequently affect the regulation of osteoclastogenesis. These results provide a possible mechanism of action of Orm in regulating osteoclastogenesis, thereby supporting the beneficial bone-protective effects of this compound.