Selective Estrogen Receptor Modulator Raloxifene Research Articles

Synthesis, biological evaluation, and stability studies of raloxifene mono- and bis-sulfamates as dual-targeting agents

All three possible sulfamate derivatives of the selective estrogen receptor modulator Raloxifene (bis-sulfamate 7 and two mono-sulfamates 8–9) were synthesized and evaluated as inhibitors of the clinical drug target steroid sulfatase (STS), both in cell-free and in cell-based assays, and also as estrogen receptor (ER) modulators. Bis-sulfamate 7 was the most potent STS inhibitor with an IC50 of 12.2 nM in a whole JEG3 cell-based assay, with the two mono-sulfamates significantly weaker. The estrogen receptor-modulating activities of 7–9 showed generally lower affinities compared to Raloxifene HCl, diethylstilbestrol and other known ligands, with mono-sulfamate 8 being the best ligand (Ki of 1.5 nM) for ERα binding, although 7 had a Ki of 13 nM and both showed desirable antagonist activity. The antiproliferative activities of the sulfamate derivatives against the T-47D breast cancer cell line showed 7 as most potent (GI50 = 7.12 µM), comparable to that of Raloxifene. Compound 7 also showed good antiproliferative potency in the NCI-60 cell line panel with a GI50 of 1.34 µM against MDA-MB-231 breast cancer cells. Stability testing of 7–9 showed that bis-sulfamate 7 hydrolyzed by desulfamoylation at a surprisingly rapid rate, initially leading selectively to 8 and finally to Raloxifene 3 without formation of 9. The mechanisms of these hydrolysis reactions could be extensively rationalized. Conversion of Raloxifene (3) into its bis-sulfamate (7) thus produced a promising drug lead with nanomolar dual activity as an STS inhibitor and ERα antagonist, as a potential candidate for treatment of estrogen-dependent breast cancer.

Discovery of PLpro and Mpro Inhibitors for SARS-CoV-2.

There are very few small-molecule antivirals for SARS-CoV-2 that are either currently approved (or emergency authorized) in the US or globally, including remdesivir, molnupiravir, and paxlovid. The increasing number of SARS-CoV-2 variants that have appeared since the outbreak began over three years ago raises the need for continual development of updated vaccines and orally available antivirals in order to fully protect or treat the population. The viral main protease (Mpro) and the papain-like protease (PLpro) are key for viral replication; therefore, they represent valuable targets for antiviral therapy. We herein describe an in vitro screen performed using the 2560 compounds from the Microsource Spectrum library against Mpro and PLpro in an attempt to identify additional small-molecule hits that could be repurposed for SARS-CoV-2. We subsequently identified 2 hits for Mpro and 8 hits for PLpro. One of these hits was the quaternary ammonium compound cetylpyridinium chloride with dual activity (IC50 = 2.72 ± 0.09 μM for PLpro and IC50 = 7.25 ± 0.15 μM for Mpro). A second inhibitor of PLpro was the selective estrogen receptor modulator raloxifene (IC50 = 3.28 ± 0.29 μM for PLpro and IC50 = 42.8 ± 6.7 μM for Mpro). We additionally tested several kinase inhibitors and identified olmutinib (IC50 = 0.54 ± 0.04 μM), bosutinib (IC50 = 4.23 ± 0.28 μM), crizotinib (IC50 = 3.81 ± 0.04 μM), and dacominitinib (IC50 = IC50 3.33 ± 0.06 μM) as PLpro inhibitors for the first time. In some cases, these molecules have also been tested by others for antiviral activity for this virus, or we have used Calu-3 cells infected with SARS-CoV-2. The results suggest that approved drugs can be identified with promising activity against these proteases, and in several cases we or others have validated their antiviral activity. The additional identification of known kinase inhibitors as molecules targeting PLpro may provide new repurposing opportunities or starting points for chemical optimization.

Simple Access to 2‐Arylbenzo[b]tellurophenes

AbstractArguably, the simplest way for the preparation of benzo[b]tellurophenes has been elaborated. Cyclization of o‐haloarylalkynes in the presence of Te‐NaOH‐DMSO triad occurs by simple mixing of starting materials and heating overnight without the need for dry and inert atmosphere and provides the corresponding benzo[b]tellurophenes in up to 90 % GC‐yield. Catalytic telluration of aryl iodide substrates extends the applicability of the developed cyclization cascade to substrates that are not suitable for the direct SNAr/5‐endo‐dig cyclization approach. Successful SEAr in the third position of benzo[b]tellurophene provides a synthetic intermediate for the preparation of Te analogues of selective estrogen receptor modulator (SERM) raloxifene.

Protective effects of combining SERMs with estrogen on metabolic parameters in postmenopausal diabetic cardiovascular dysfunction: The role of cytokines and angiotensin II

IntroductionThe beneficial effects of the administration of selective estrogen receptor modulators (SERMs) and estrogen (E2), alone or in combination with each other, have been reported in postmenopausal diabetic cardiovascular dysfunction. In the present study, we determined the mechanism of action of SERMs and E2 on inflammatory balance, angiotensin II (Ang II) serum levels, and glycemic profile in a postmenopausal diabetic rat model. MethodsOvariectomized rats with type 2 diabetes received daily SERMs (tamoxifen and raloxifene) and E2 for one month. After treatment, cardiovascular risk indices, glycemic profile, and serum Ang II, TNF-α and IL-10 levels were measured. ResultsType 2 diabetes caused an abnormal glycemic profile, which was exacerbated by ovariectomy. All treatments inhibited the effects of diabetes and ovariectomy on the glycemic profile, with combined treatments (SERMs + E2) showing stronger effects. Cardiovascular risk indices that became abnormal by diabetes and worsened by ovariectomy were improved in all treatment modalities. Also, combined treatment reduced serum Ang II, TNF-α, and the ratio of TNF-α to IL-10, indicating an improvement in inflammatory balance. ConclusionOur study showed the administration of SERMs and E2, alone or in combination, could be an effective alternative in the treatment of menopausal diabetes, and generally, the beneficial effects of combined treatments were more effective than the effects of E2 or SERMs alone. It appears that E2 or SERMs benefit the cardiovascular system by improving inflammatory balance and reducing Ang II levels.

Selective estrogen receptor modulators (SERMs) affect cholesterol homeostasis through the master regulators SREBP and LXR

Selective estrogen receptor modulators (SERMs) are nonsteroidal drugs that display an estrogen‐agonist or estrogen‐antagonist effect depending on the tissue targeted. SERMs have attracted great clinical interest for the treatment of several pathologies, most notably breast cancer and osteoporosis. There is strong evidence that SERMs secondarily affect cholesterol metabolism, although the mechanism has not been fully elucidated. In this study, we analysed the effect of the SERMs tamoxifen, raloxifene, and toremifene on the expression of lipid metabolism genes by microarrays and quantitative PCR in different cell types, and ascertained the main mechanisms involved. The three SERMs increased the expression of sterol regulatory element‐binding protein (SREBP) target genes, especially those targeted by SREBP-2. In consonance, SERMs increased SREBP‐2 processing. These effects were associated to the interference with intracellular LDL-derived cholesterol trafficking. When the cells were exposed to LDL, but not to cholesterol/methyl-cyclodextrin complexes, the SERM-induced increases in gene expression were synergistic with those induced by lovastatin. Furthermore, the SERMs reduced the stimulation of the transcriptional activity of the liver X receptor (LXR) by exogenous cholesterol. However, their impact on the expression of the LXR canonical target ABCA1 in the presence of LDL was cell-type dependent. These actions of SERMs were independent of estrogen receptors. We conclude that, by inhibiting the intracellular trafficking of LDL-derived cholesterol, SERMs promote the activation of SREBP-2 and prevent the activation of LXR, two master regulators of cellular cholesterol metabolism. This study highlights the impact of SERMs on lipid homeostasis regulation beyond their actions as estrogen receptor modulators.

Structural insights of the conserved “priming loop” of hepatitis B virus pre-genomic RNA

Initiation of protein-primed (-) strand DNA synthesis in hepatitis B virus (HBV) requires interaction of the viral polymerase with a cis-acting regulatory signal, designated epsilon (ε), located at the 5′-end of its pre-genomic RNA (pgRNA). Binding of polymerase to ε is also necessary for pgRNA encapsidation. While the mechanistic basis of this interaction remains elusive, mutagenesis studies suggest its internal 6-nt “priming loop” provides an important structural contribution. ε might therefore be considered a promising target for small molecule interventions to complement current nucleoside-analog based anti-HBV therapies. An ideal prerequisite to any RNA-directed small molecule strategy would be a detailed structural description of this important element. Herein, we present a solution NMR structure for HBV ε which, in combination with molecular dynamics and docking simulations, reports on a flexible ligand “pocket”, reminiscent of those observed in proteins. We also demonstrate the binding of the selective estrogen receptor modulators (SERMs) Raloxifene, Bazedoxifene, and a de novo derivative to the priming loop. Communicated by Ramaswamy H. Sarma

Selective oestrogen receptor modulators (SERMs) for endometriosis.

Endometriosis is defined as the presence of endometrial tissue outside the uterine cavity. This chronic and recurring condition occurs in women of reproductive age. It is a common cause of pain or infertility and can cause non-specific symptoms such as lower back pain, dyspareunia (pain during or after intercourse), and dysmenorrhoea (menstrual pain). Endometriosis is an oestrogen-dependent disease. Medical treatment aims to relieve symptoms and shrink lesions by suppressing the normal menstrual cycle. In this review, we consider medication specifically aiming to modulate oestrogen receptors as an alternative method of treatment. To evaluate the effectiveness and safety of selective oestrogen receptor modulators (SERMs) in the management of endometriosis. We searched for trials in the following databases (from their inception to 28 May 2020): Cochrane Gynaecology and Fertility Group Specialised Register, Cochrane Central Register of Studies (CRS Online), MEDLINE, Embase, CINAHL, PsycINFO, and registers of ongoing trials. In addition, we searched all reference lists of included trials, and we contacted experts in the field, in an attempt to locate trials. We included randomised controlled trials (RCTs) comparing selective oestrogen receptor modulators (SERMs)with placebo, no treatment, other medical treatment, or surgery for endometriosis. We used standard methodological procedures recommended by Cochrane. Two review authors independently selected trials for inclusion, assessed risk of bias, and extracted data using data extraction forms. We used risk ratios (RRs) with 95% confidence intervals (CIs) for reporting dichotomous data. Primary review outcomes were relief of pelvic pain and adverse events. Secondary outcomes included quality of life, recurrence rate, and economic and fertility outcomes. We included only one RCT, which included 93 women, comparing the SERM raloxifene with placebo in biopsy-proven endometriosis. Allwomen first underwentcomplete surgical excision of all lesions. Evidence was of very low quality: the main limitation was imprecision - with very sparse data from only one small study, which included only women after surgical treatment. Relief of pelvic pain The included study did not specifically measure the primary outcome of pain relief. Study authors reported that time to return of pelvic pain (defined as two months of pain equal to or more severe than pain at study entry) was more rapid in the raloxifene group (P = 0.03). Adverse events The included study reported adverse events such as pelvic pain, ovarian cyst, headache, migraine, and depression. We are uncertain whether raloxifene improves the incidence of pelvic pain (RR 1.25, 95% CI 0.63 to 2.45), ovarian cysts (RR 1.57, 95% CI 0.55 to 4.43), headache (RR 1.09, 95% CI 0.49 to 2.43), migraine (RR 0.73, 95% CI 0.28 to 1.95), depression (RR 1.96, 95% CI 0.63 to 6.06), or other adverse events (RR 0.08, 95% CI 0.00 to 1.30) (all: 1 study, n = 93; very low-quality evidence). Quality of life The study describeda statistically significant difference in mental health quality of life(QoL) by 12 months, in favour of placebo treatment (mean difference 11.1, 95% CI 0.01 to 21.19). Other QoL data did not differ between groups but were not reported in detail. Recurrence rate, fertility, and economic outcomes We are uncertain whether raloxifene improves the recurrence rate of endometriosis,proven by biopsy, when compared to placebo (RR 1.20, 95% CI 0.66 to 2.21; 1 study, n = 93; very low-quality evidence). Thissuggests that if 28% of women taking placebo have biopsy-proven recurrence of endometriosis, between 19% and 62% of those taking raloxifene will do so. These outcomes are prone to bias, as not all women had an actual second laparoscopy. Recurrence based on symptoms (non-menstrual pain, dysmenorrhoea, or dyspareunia) was described; in these cases, symptoms improved after use of raloxifene as well as after use of placebo. The included study did not report data on economic outcomes. No comparative data were available on pregnancy, as the study included only women who agreed to postpone pregnancy until after the study endpoint; the few pregnancies that did occur were uneventful but were regarded as an adverse event. AUTHORS' CONCLUSIONS: Based on a single, small RCT and incomplete data, we are uncertain of the effects of SERMs on pain relief in surgically treated patients with endometriosis. The included study was stopped prematurely because of higher pain scores among women who took SERMs when compared to scores among those receiving placebo. Further research is needed to fully evaluate the role of SERMs in endometriosis.

Raloxifene prevents stress granule dissolution, impairs translational control and promotes cell death during hypoxia in glioblastoma cells

Glioblastoma (GBM) is the most common primary malignant brain tumor, and it has a uniformly poor prognosis. Hypoxia is a feature of the GBM microenvironment, and previous work has shown that cancer cells residing in hypoxic regions resist treatment. Hypoxia can trigger the formation of stress granules (SGs), sites of mRNA triage that promote cell survival. A screen of 1120 FDA-approved drugs identified 129 candidates that delayed the dissolution of hypoxia-induced SGs following a return to normoxia. Amongst these candidates, the selective estrogen receptor modulator (SERM) raloxifene delayed SG dissolution in a dose-dependent manner. SG dissolution typically occurs by 15 min post-hypoxia, however pre-treatment of immortalized U251 and U3024 primary GBM cells with raloxifene prevented SG dissolution for up to 2 h. During this raloxifene-induced delay in SG dissolution, translational silencing was sustained, eIF2α remained phosphorylated and mTOR remained inactive. Despite its well-described role as a SERM, raloxifene-mediated delay in SG dissolution was unaffected by co-administration of β-estradiol, nor did β-estradiol alone have any effect on SGs. Importantly, the combination of raloxifene and hypoxia resulted in increased numbers of late apoptotic/necrotic cells. Raloxifene and hypoxia also demonstrated a block in late autophagy similar to the known autophagy inhibitor chloroquine (CQ). Genetic disruption of the SG-nucleating proteins G3BP1 and G3BP2 revealed that G3BP1 is required to sustain the raloxifene-mediated delay in SG dissolution. Together, these findings indicate that modulating the stress response can be used to exploit the hypoxic niche of GBM tumors, causing cell death by disrupting pro-survival stress responses and control of protein synthesis.

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 modulator with estrogen does not affect the proliferation and apoptosis of uterine leiomyoma cells.

BackgroundThe administration of menopausal hormone therapy (MHT) in women with uterine leiomyomas is still debated. The purpose of this article is to study the proliferation and apoptosis of uterine leiomyoma cells under the impact of selective estrogen receptor modulator (SERM) combined with estrogen.MethodsPrimary cultured uterine leiomyoma cells in the perimenopausal period were treated with estrogen (17-beta estradiol) + SERM (raloxifene) as the tissue selective estrogen complex (TSEC) group, while both estrogen + medroxyprogesterone acetate (E+P) and estrogen (E) alone as were used as control groups. The expression of proliferating cell nuclear antigen (PCNA) and B-cell lymphoma-2 (Bcl-2) proteins was assessed by methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay and western-blot analysis, respectively.ResultsThe proliferation in the TSEC group was weaker than the control groups (P<0.001). There was no statistical difference between the TSEC and blank control group on cell proliferation at 72 h (P=0.13). However, there was a significant difference between the other groups (P<0.001). PCNA expression of TSEC was lower than that of the E + P and E groups (P<0.05). There was no statistical difference in the expression of PCNA between the TSEC and blank control groups (P=0.63). Bcl-2 expression of TSEC was lower than that of the E + P and E groups (P<0.05). There was no statistical difference in the expression of Bcl-2 between the TSEC group and the blank control group (P=0.60).ConclusionsSERM combined with estrogen may have a better safety for perimenopausal women with uterine leiomyoma in MHT.

Incidence of venous thromboembolism among postmenopausal women prescribed ospemifene, selective estrogen receptor modulators for noncancer indications, or untreated vulvar and vaginal atrophy.

Ospemifene is a nonsteroidal selective estrogen receptor modulator (SERM) for the treatment of moderate symptomatic vulvar and vaginal atrophy (VVA) due to menopause. A postauthorization safety study is currently examining the incidence of venous thromboembolism (VTE) among postmenopausal women receiving ospemifene or other SERM (raloxifene, bazedoxifene, or tamoxifen, for noncancer indications), or with untreated VVA. This interim analysis used the US MarketScan Commercial and Medicare Supplemental claims database from 2013 to 2017 to identify incident VTE. The incidence rate and 95% confidence interval of VTE during the first continuous course of treatment (or continuous untreated time for the untreated cohort) were calculated for each cohort overall and by age group, with sensitivity analyses examining incidence in the short term (up to 90 days) and long term (all available follow-up, regardless of treatment changes). Analyses included 8,188 ospemifene users, 11,777 other SERM users, and 220,242 women with untreated VVA. The incidence per 1,000 person-years and 95% confidence interval of VTE were 3.7 (1.7-7.1) for ospemifene, 11.5 (8.9-14.6) for other SERM, and 11.3 (10.8-11.7) for untreated VVA. Stratification by age and altering the time frame for analysis produced results with similar patterns to the primary analysis. This interim analysis of an ongoing study suggests a favorable safety profile for ospemifene with respect to VTE. Comparative analyses with covariate adjustment will be performed when data accrual is complete.

Abstract P3-08-71: Medication use to reduce mammographic breast density in premenopausal women: A systematic review

Abstract Background: Mammographic breast density (MBD) is a strong modifiable risk factor for breast cancer, especially in premenopausal women. It is estimated that up to 39% of breast cancer cases in premenopausal women could potentially be prevented by reducing dense breasts to non-dense breasts. Therefore, reducing breast density through targeted interventions is an excellent opportunity to substantially reduce breast cancer incidence in premenopausal women. We performed a critical evaluation of the literature to determine the associations of chemoprevention agents use with MBD. This will guide the management of premenopausal women at risk for breast cancer. Methods: Eleven databases were searched on July 2019. We included interventional, cross-sectional, longitudinal or observational studies in Englishreporting the associations of medication with mammographic breast density in premenopausal womenwith no history of breast cancer. Two researchers extracted the data and assessed the quality of the studies. Supplements not otherwise specified were excluded. Results: After de-duplication process, 1,464 citations were screened for eligibility. Seven studies met our inclusion criteria: two observational, four randomized controlled, and one non-randomized controlled trials (RCT). There were two categories of medications: dietary supplements (i.e. vitamin D, calcium, isoflavone) and drugs (non-steroidal anti-inflammatory drugs [NSAIDs], selective estrogen receptor modulators (SERMs) goserelin, and GnRHA deslorelin acetate). In observational studies, calcium use was associated with a significant reduction in MBD, while vitamin D and NSAIDs showed no reduction6. Likewise, Isoflavone and vitamin D in doses of 1000, 2000 or 3,000IU/day were not associated with a reduction in MBD in two different RCT. Groselin, GnRHA, deslorein acetate, statins were not associated with MBD reduction in an RCT’s. SERMs (tamoxifene and raloxifene) were the only drugs associated with reductions in MBD in RCTs. Conclusions: Only a very limited number of medications (SERMs) are associated with reductions in MBD. In view of their low uptake and adherence, identifying other medications that can reduce MBD is crucial, as these could have utility in breast cancer prevention. Citation Format: Ana S. Salazar, Malika Rakhmankulova, Laura E. Simmon, Adetunji Toriola. Medication use to reduce mammographic breast density in premenopausal women: A systematic review [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-08-71.

Osteoporosis: long-term treatment versus drug holiday-what is the evidence?

The occurrence of multiple vertebral fractures after discontinuation of denosumab in the treatment of osteoporosis has reopened the debate on the optimal treatment duration and drug holidays.In principle, there is a difference in this regard between the discontinuation of medications such as bisphosphonates and substances without bone retention such as selective estrogen receptor modulators (SERMs), denosumab or teriparatide. Even after the end of application bisphosphonates have avery long half-life in the bones. After cessation of drug intake there is a slow, slight increase of bone turnover markers. Even after cessation of the SERM raloxifene, a decline in bone density can be observed, as with the termination of teriparatide. In contrast to these osteoporosis medications, after cessation of denosumab, asteep and rapid increase in markers of bone resorption above baseline levels ("rebound") and a reduction in bone mineral density to initial values can be observed.Osteoporosis is a disease that carries an increased risk of fracture, which is reduced for the duration of osteoporosis treatment. In certain situations, the fracture risk is only temporarily raised. In these situations, cessation of the osteoporosis treatment is possible. Beyond these special clinical situations, however, osteoporosis needs to be addressed as achronic disease with a permanently increased fracture risk and the indication for therapy should be evaluated according to the extent of the risk of fracture.What happens after discontinuation of anti-osteoporosis drugs? The various effects on bone turnover markers, bone mineral density and fracture incidence of the individual drug groups are presented in detail, as are the resulting recommendations of the task forces of the American Society of Bone and Mineral Research (ASBMR) and the European Calcified Tissue Society (ECTS).

Benefits and harms of selective oestrogen receptor modulators (SERMs) to reduce breast cancer risk: a cross-sectional study of methods to communicate risk in primary care.

In Australia, evidence-based guidelines recommend that women consider taking selective oestrogen receptor modulators (SERMs) to reduce their risk of breast cancer. In practice, this requires effective methods for communicating the harms and benefits of taking SERMs so women can make an informed choice. To evaluate how different risk presentations influence women's decisions to consider taking SERMs. Cross-sectional, correlational study of Australian women in general practice. Three risk communication formats were developed that included graphics, numbers, and text to explain the reduction in breast cancer risk and risk of side effects for women taking SERMs (raloxifene or tamoxifen). Women aged 40-74 years in two general practices were shown the risk formats using vignettes of hypothetical women at moderate or high risk of breast cancer and asked to choose 'If this was you, would you consider taking a SERM?' Descriptive statistics and predictors (risk format, level of risk, and type of SERM) of choosing SERMs were determined by logistic regression. A total of 288 women were recruited (an 88% response rate) between March and May 2017. The risk formats that showed a government statement and an icon array were associated with a greater likelihood of considering SERMs relative to one that showed a novel expected frequency tree. Risk formats for raloxifene and for the high-risk vignettes were also more strongly associated with choosing to consider SERMs. No associations were found with any patient demographics. Specific risk formats may lead to more women considering taking SERMs to reduce breast cancer risk, especially if they are at high risk of the condition. Raloxifene may be a more acceptable SERM to patients.

The selective estrogen receptor modulator raloxifene mitigates the effect of all-trans-retinal toxicity in photoreceptor degeneration

The retinoid cycle is a metabolic process in the vertebrate retina that continuously regenerates 11-cis-retinal (11-cisRAL) from the all-trans-retinal (atRAL) isomer. atRAL accumulation can cause photoreceptor degeneration and irreversible visual dysfunction associated with incurable blinding retinal diseases, such as Stargardt disease, retinitis pigmentosa (RP), and atrophic age-related macular degeneration (AMD). The underlying cellular mechanisms leading to retinal degeneration remain uncertain, although previous studies have shown that atRAL promotes calcium influx associated with cell apoptosis. To identify compounds that mitigate the effects of atRAL toxicity, here we developed an unbiased and robust image-based assay that can detect changes in intracellular calcium levels in U2OS cells. Using our assay in a high-throughput screen of 2,400 compounds, we noted that selective estrogen receptor modulators (SERMs) potently stabilize intracellular calcium and thereby counteract atRAL-induced toxicity. In a light-induced retinal degeneration mouse model (Abca4-/-Rdh8-/-), raloxifene (a benzothiophene-type scaffold SERM) prevented the onset of photoreceptor apoptosis and thus protected the retina from degeneration. The minor structural differences between raloxifene and one of its derivatives (Y 134) had a major impact on calcium homeostasis after atRAL exposure in vitro, and we verified this differential impact in vivo In summary, the SERM raloxifene has structural and functional neuroprotective effects in the retina. We propose that the highly sensitive image-based assay developed here could be applied for the discovery of additional drug candidates preventing photoreceptor degeneration.

Selective Estrogen Receptor Modulator Raloxifene as a Possible Regulator of Arginine Vasopressin

Denise Börzsei1, Renáta Szabó1,2, Alexandra Hoffmann1, Krisztina Kupai1, Anikó Magyariné Berkó1, Csaba Varga1 and Anikó Pósa1,2* Author Affiliations 1Department of Physiology, Anatomy and Neuroscience, Faculty of Science and Informatics, Hungary 2Department of Physiology, Anatomy and Neuroscience, Interdisciplinary Excellence Centre, Hungary Received: April 08, 2019 | Published: April 18, 2019 Corresponding author: Anikó Pósa, Department of Physiology, Anatomy and Neuroscience, Szeged, Hungary DOI: 10.26717/BJSTR.2019.17.002969

Identifying Mitochondrial Targets for Pancreatic Cancer Employing Unconventional Combinations of Middle Eastern Phytoextracts with Raloxifene

PCa has a high mortality, substantial chemoresistance, and a poor 5‐year survival rate of 6 to 8%. It is the fourth leading cause of deaths due to cancer in the United States, killing over 53,000 Americans each year, and 250,000 people worldwide. Little is known about the regulation of mitophagy in PCa by drugs and dietary components. There is also a gap in knowledge concerning molecular interactions between drugs and food and the K‐ras pathway in PCa. This is important because mutations in the human homologue of the Kirsten Rat Sarcoma (KRAS) viral oncogene occur in 90% of PCa patients and drive the early development of PCa. Our previous work showed that enhanced mitophagy, which prevents the accumulation of damaged mitochondria in PCa cells was alleviated by repurposing the FDA‐approved selective estrogen receptor modulator raloxifene to treat PCa cells. Here, we used a combination of Middle Eastern dietary components (MEDC) and raloxifene to mitigate mitochondrial renewal and identify novel mitochondrial targets for PCa. We screened crude aqueous extracts from six spices and plants used in Middle Eastern and Indian cuisines, including artichoke (Cynara scolymus), curry leaf (Murraya koenigii), dill (Anethum graveolens), noni (Morinda citrifolia), olive (Olea europaea), rose (Rosa damascena), and sumac (Rhus coriaria) for cytotoxicity in the PCa cell lines, MIA PaCa‐2 (similar KRAS gene mutation as majority of patients) and PANC‐1 (less common KRAS gene mutation). Specifically, we treated PCa cells in vitro with exponentially increasing doses of aqueous extracts at 300 ng/mL, 3 μg/mL, 30 μg/mL, and 300 μg/mL for 48 hours followed by an MTT assays. Aqueous extracts of sumac and artichoke (AESA) induced maximum cytotoxicity, which was exacerbated by raloxifene (AESA‐R). To address whether cytotoxicity was limited to PCa cells, we used NIH‐3T3 cells as a non‐cancer control, showing a sparing effect. We also tested 1:1 combinations of AESA and found evidence of activity. To identify specific compounds, using a fractional approach based on preparative HPLC, 100 mg of the residue was chromatographed onto a silica gel column and gradient eluted using dichloromethane/methanol (gradient, 0, 100%, v/v). Fractions and eluates were monitored by thin layer chromatography using precoated silica gel 60 F254, 0.25 mm aluminum backed plates. Cytotoxic fractions were reconstituted in deuterated solvents and analyzed by NMR spectroscopy to identify pentagalloyl glucose as the bioactive component in sumac. To elucidate the mechanism for the cytotoxicity, we showed that AESA and AESA‐R activated caspase‐3 and 7, induced mitochondrial ROS, and reduced mitochondrial membrane potential in PCa cells, starting within 20 minutes and sustained for 48 hours following treatment. Western blot showed changes in the expression of proapoptotic (bim) and the translocation of antiapoptotic proteins (Bcl2), sustained over 48 hours. Our data demonstrate for the first time that specific food‐drug combinations alter mitochondrial biology and response including the regulation of mitophagy in PCa cells.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Estrogens and selective estrogen receptor modulators differentially antagonize Runx2 in ST2 mesenchymal progenitor cells

Estrogens attenuate bone turnover by inhibiting both osteoclasts and osteoblasts, in part through antagonizing Runx2. Apparently conflicting, stimulatory effects in osteoblast lineage cells, however, sway the balance between bone resorption and bone formation in favor of the latter. Consistent with this dualism, 17ß-estradiol (E2) both stimulates and inhibits Runx2 in a locus-specific manner, and here we provide evidence for such locus-specific regulation of Runx2 by E2 in vivo. We also demonstrate dual, negative and positive, regulation of Runx2-driven alkaline phosphatase (ALP) activity by increasing E2 concentrations in ST2 osteoblast progenitor cells. We further compared the effects of E2 to those of the Selective Estrogen Receptor Modulators (SERMs) raloxifene (ral) and lasofoxifene (las) and the phytoestrogen puerarin. We found that E2 at the physiological concentrations of 0.1–1 nM, as well as ral and las, but not puerarin, antagonize Runx2-driven ALP activity. At ≥10 nM, E2 and puerarin, but not ral or las, stimulate ALP relative to the activity measured at 0.1–1 nM. Contrasting the difference between E2 and SERMs in ST2 cells, they all shared a similar dose-response profile when inhibiting pre-osteoclast proliferation. That ral and las poorly mimic the locus- and concentration-dependent effects of E2 in mesenchymal progenitor cells may help explain their limited clinical efficacy.

O10.7. INVESTIGATING THE MECHANISMS UNDERLYING THE BENEFICIAL EFFECTS OF ESTROGENS IN SCHIZOPHRENIA

BackgroundEstrogens, in particular 17β-estradiol (estradiol) have repeatedly been shown to exert powerful influences over cognitive function, and in particular, on a range of cognitive behaviours associated with neurodevelopmental disorders. This includes depressive and anxious behaviours as well as learning and memory (including working memory). These cognitive enhancing effects have been shown to be dependent on increases in the number of dendritic spines as well as alterations in glutamate receptor transmission and regulation of synaptic protein expression. Modulation of these synaptic functions can result in long-term increases in synaptic connectivity.Interestingly, there is growing evidence that estrogenic-based compounds may have a positive effect in the treatment of a number of neuropsychiatric disorders, including schizophrenia. Importantly, recent clinical studies have demonstrated that adjunct treatment with estradiol or the selective estrogen receptor modulator (SERM) raloxifene, ameliorates positive and negative symptoms and improves working memory and attention deficits in male and female schizophrenic patients. However, it has been argued that estrogenic-based compounds are not an effective treatment option owing to potential serve side effects associated with long-term administration. It is, however, of note that the precise mechanisms that underlie the positive effects of estradiol, or estrogenic-based compounds, in this disease are currently unclear. Therefore, determining how estradiol exerts its positive effects in health as well as in disease, will aid in the development of safer and more effective estrogenic-based compounds.MethodsHere, we have used human induced pluripotent stem cell (iPSC)-derived from healthy or patients diagnosed schizophrenic but with no common genetic background to study the potential mechanism that may underlie estrogens beneficial effects in disease. iPSCs were differentiated into young, developing, cortical neurons using well established methods. First, we assessed the ability of estrogens to modulate key neuronal and synaptic structures as well as synaptic and inflammatory genes. Next, we assessed the expression and distribution of synaptic proteins were determined in both healthy iPSC-neurons and patient iPSC-neurons (from 3–6 individuals from each group). Subsequently, using a pharmacological approach, we have explored the ability of estrogens to rescue cellular and molecular deficits in iPSC-neurons derived from schizophrenic patients.ResultsBoth healthy and patient iPSC differentiated into neuroepithelium, neural progenitors cells and finally into TBR1- and EMX1-positive neurons efficiently. Assessment of synaptic protein expression revealed reduced expression of key synaptic proteins involved in excitatory transmission compared to control lines. When healthy iPSC-neurons were treated with a range of estrogenic compounds, we observed a robust increase in the expression of key synaptic protein including GRIN1 and DGL4. Consistent with previous reports, patient iPSC-neurons displayed reduced synaptic protein expression compared with healthy iPSC-neurons. Critically, when patient iPSC-neurons were treated with 17β-estradiol or raloxifene, we observed an increase in synaptic protein expression to a level similar to that observed in untreated healthy iPSC-neurons.DiscussionThese data are the first to demonstrate that estrogens are capable of regulating synaptic proteins in human neurons taken from patients diagnosed with schizophrenia. Collectively, we hope these data will help us understand how estrogens may confer their positive effects in psychiatric disorders.

Study of micelle and metal complexation-mediated fluorescence enhancements of raloxifene hydrochloride. Application to pharmaceutical analysis

The fluorescence behavior of the selective estrogen receptor modulator raloxifene hydrochloride (RXF) was investigated for the first time. The weak fluorescence of RXF was greatly enhanced by 2.2 folds in borate buffer (pH8.0)/sodium dodecyl sulfate (SDS) solution. As well, complex formation with Al3+ in borate buffer (pH8.5) gave rise to 1.9 folds enhancement in RXF fluorescence. Based on these outcomes, two simple and sensitive fluorimetric methods were established for the quantification of RXF in tablets. The intensity of RXF-SDS fluorescence was optimum at 583nm after excitation at 290nm (Method-I) and that of RXF-Al3+ complex was optimum at 594nm after excitation at 296nm (Method-II). Different fluorescence parameters such as quantum yield and fluorophore brightness were calculated and compared with those of the drug itself. The molar ratio of RXF-Al3+ complex was calculated and a reaction pathway was deduced. Linearity was attained from 0.1 to 1.5 and from 0.1 to 2.0μg/mL with lower detection limits of 0.01 and 0.02μg/mL for Methods-I and -II, respectively. Application of the two methods to quantify RXF in tablets was successfully done with mean recoveries of 98.19±1.01% and 98.64±1.49%, respectively. The results obtained by the proposed methods and the official USP method agreed well.