Raloxifene (LY139481 HCI) prevents bone loss and reduces serum cholesterol without causing uterine hypertrophy in ovariectomized rats

Why Animal Experiments Are Still Indispensable in Bone Research: A Statement by the European Calcified Tissue Society

Major achievements in bone research have always relied on animal models and in vitro systems derived from patient and animal material. However, the use of animals in research has drawn intense ethical debate and the complete abolition of animal experimentation is demanded by fractions of the population. This phenomenon is enhanced by the reproducibility crisis in science and the advance of in vitro and in silico techniques. 3D culture, organ-on-a-chip, and computer models have improved enormously over the last few years. Nevertheless, the overall complexity of bone tissue cross-talk and the systemic and local regulation of bone physiology can often only be addressed in entire vertebrates. Powerful genetic methods such as conditional mutagenesis, lineage tracing, and modeling of the diseases enhanced the understanding of the entire skeletal system. In this review endorsed by the European Calcified Tissue Society (ECTS), a working group of investigators from Europe and the US provides an overview of the strengths and limitations of experimental animal models, including rodents, fish, and large animals, as well the potential and shortcomings of in vitro and in silico technologies in skeletal research. We propose that the proper combination of the right animal model for a specific hypothesis and state-of-the-art in vitro and/or in silico technology is essential to solving remaining important questions in bone research. This is crucial for executing most efficiently the 3R principles to reduce, refine, and replace animal experimentation, for enhancing our knowledge of skeletal biology, and for the treatment of bone diseases that affect a large part of society. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Quercetin and Ferulic Acid Elicit Estrogenic Activities In Vivo and In Silico

In this study, we examined the sub-acute toxicity of quercetin and ferulic acid and evaluated their effects on protein, cholesterol, and estrogen levels in vivo. Six groups of female Wistar rats were fed by gavage. The first and second groups represent the positive (Clomiphene citrate 10 mg/kg) and negative (NaCl 0.9%) control groups, while the other groups received quercetin and ferulic acid at doses of 5 and 10 mg/kg/day for 28 days. The sub-acute toxicity was monitored by examining the weights, biochemical parameters (AST, ALT, ALP, urea, and CREA), and histological changes in the kidneys and liver of the treated animals. Furthermore, the in vivo estrogenic effects were studied in terms of the serum and ovarian cholesterol levels, serum estradiol, and uterine proteins. Finally, Docking studies were conducted to evaluate the binding affinity of quercetin and ferulic acid for alpha and beta estrogen receptors. Results showed that both compounds were devoid of any signs of nephrotoxicity or hepatotoxicity. Additionally, quercetin and ferulic acid caused significant estrogenic effects evidenced by an increase of 8.7 to 22.48% in serum estradiol, though to a lesser amount than in the reference drug-treated group (64.21%). Moreover, the two compounds decreased the serum cholesterol levels (12.26-32.75%) as well as the ovarian cholesterol level (11.9% to 41.50%) compared to the negative control. The molecular docking in estrogen alpha and estrogen beta active sites showed high affinity of quercetin (-10.444 kcal/mol for estrogen alpha and -10.662 kcal/mol for estrogen beta) and ferulic acid (-6.377 kcal/mol for estrogen alpha and -6.3 kcal/mol for estrogen beta) to these receptors. This study provides promising insights into the potential use of quercetin as a therapeutic agent for the management of female fertility issues.

Membrane estrogen receptor α signaling modulates the sensitivity to estradiol treatment in a dose- and tissue- dependent manner

Estradiol (E2) affects both reproductive and non-reproductive tissues, and the sensitivity to different doses of E2 varies between tissues. Membrane estrogen receptor α (mERα)-initiated signaling plays a tissue-specific role in mediating E2 effects, however, it is unclear if mERα signaling modulates E2 sensitivity. To determine this, we treated ovariectomized C451A females, lacking mERα signaling, and wildtype (WT) littermates with physiological (0.05 μg/mouse/day (low); 0.6 μg/mouse/day (medium)) or supraphysiological (6 μg/mouse/day (high)) doses of E2 (17β-estradiol-3-benzoate) for three weeks. Low-dose treatment increased uterus weight in WT, but not C451A mice, while non-reproductive tissues (gonadal fat, thymus, trabecular and cortical bone) were unaffected in both genotypes. Medium-dose treatment increased uterus weight and bone mass and decreased thymus and gonadal fat weights in WT mice. Uterus weight was also increased in C451A mice, but the response was significantly attenuated (- 85%) compared to WT mice, and no effects were triggered in non-reproductive tissues. High-dose treatment effects in thymus and trabecular bone were significantly blunted (- 34% and - 64%, respectively) in C451A compared to WT mice, and responses in cortical bone and gonadal fat were similar between genotypes. Interestingly, the high dose effect in uterus was enhanced (+ 26%) in C451A compared to WT mice. In conclusion, loss of mERα signaling reduces the sensitivity to physiological E2 treatment in both non-reproductive tissues and uterus. Furthermore, the E2 effect after high-dose treatment in uterus is enhanced in the absence of mERα, suggesting a protective effect of mERα signaling in this tissue against supraphysiological E2 levels.

Praeruptorin B inhibits osteoclastogenesis by targeting GSTP1 and impacting on the S-glutathionylation of IKKβ

Osteoporosis a common disease in postmenopausal women which contains significant impact on the living quality of women. With the aging of the population, the number of patients suffer from osteoporosis has shown a significant increase. Given the limitations of clinical drugs for the treatment of osteoporosis, natural extracts with small side effects have a great application prospect in the treatment of osteoporosis. Praeruptorin B (Pra-B), is one of the main components found in the roots of Peucedanum praeruptorum Dunn and exhibits anti-inflammatory effects. However, there is no research on the influence of Pra-B on osteoporosis. Here, we showed that Pra-B can dose-dependently suppress osteoclastogenesis without cytotoxicity. Receptor activator of nuclear factor kappa-B (NF-κB) ligand (RANKL)-induced the nuclear import of P65 was inhibited by Pra-B, which indicated the suppressive effect of Pra-B on NF-κB signaling. Further, Pra-B enhanced the expression of Glutathione S-transferase Pi 1 (GSTP1) and promoted the S-glutathionylation of IKKβ to inhibit the nuclear translocation of P65. Moreover, in vivo experiments showed that Pra-B considerably attenuated the bone loss in ovariectomy (OVX)-induced mice. Collectively, our studies revealed that Pra-B suppress the NF-κB signaling targeting GSTP1 to rescued RANKL-induced osteoclastogenesis in vitro and OVX-induced bone loss in vivo, supporting the potential of Pra-B for treating osteoporosis in the future.

Searching for an ideal SERM: Mining tamoxifen structure-activity relationships

The repurposing of old drugs for new treatments has recently garnered increased attention in the face of new diseases and declining productivity of the pharmaceutial industry. This report draws attention to potential opportunities hiding in plain sight within the SAR of off-patent drugs. Herein we explore the untapped potential of Selective Estrogen Receptor Modulators (SERMs). SERMs are a class of molecules that have been highly influential in the treatment of estrogen receptor-positive breast cancers. However, the most commonly prescribed SERM, tamoxifen, has been found to increase the risk of endometrial cancer. Another SERM, raloxifene, does not increase incidence of endometrial cancer, but has been abandoned as a breast cancer treatment. We report the design, synthesis, and evaluation of an unexplored tamoxifen substitution pattern which mimics the geometry of raloxifene to confer its favorable pharmacodynamics. This substitution pattern was found to maintain excellent binding affinity to estrogen receptor-α.

Turning scientific serendipity into discoveries in breast cancer research and treatment: a tale of PhD students and a 50-year roaming tamoxifen team

PURPOSE

This retrospective, about a single "mobile" laboratory in six locations on two continents, is intended as a case study in discovery for trainees and junior faculty in the medical sciences. Your knowledge of your topic is necessary to expect the unexpected.

HISTORICAL METHOD

In 1972, there was no tamoxifen, only ICI 46, 474, a non-steroidal anti-estrogen with little chance of clinical development. No one would ever be foolish enough to predict that the medicine, 20 years later, would achieve legendary status as the first targeted treatment for breast cancer, and millions of women would benefit from long-term adjuvant tamoxifen therapy. The secret of tamoxifen's success was a translational research strategy proposed in the mid 1970's. This strategy was to treat only patients with estrogen receptor (ER)-positive breast cancer and deploy 5 or more years of adjuvant tamoxifen therapy to prevent recurrence. Additionally, tamoxifen prevented mammary cancer in animals. Could the medicine prevent breast cancer in women?

RESULTS

Tamoxifen and the failed breast cancer drug raloxifene became the first selective estrogen receptor modulators (SERMs): a new drug group, discovered at the University of Wisconsin, Comprehensive Cancer Center. Serendipity can play a fundamental role in discovery, but there must be a rigorous preparation for the investigator to appreciate the possibility of a pending discovery. This article follows the unanticipated discoveries when PhD students "get the wrong answer." The secret of success of my six Tamoxifen Teams was their technical excellence to create models, to decipher mechanisms, that drove the development of new medicines. Discoveries are listed that either changed women's health or allowed an understanding of originally opaque mechanisms of action of potential therapies. These advances in women's health were supported entirely by government-sponsored peer-reviewed funding and major philanthropy from the Lynn Sage Breast Cancer Foundation, the Avon Foundation, and the Susan G. Komen Breast Cancer Foundation. The resulting lives saved or extended, families aided in a time of crisis and the injection of billions of dollars into national economies by drug development, is proof of the value of Federal or philanthropic investment into unencumbered research aimed at saving millions of lives.

Current and emerging estrogen receptor-targeted therapies for the treatment of breast cancer

Nearly 80% of all breast cancers are estrogen receptor positive (ER+) and require the activity of this transcription factor for tumor growth and survival. Thus, endocrine therapies, which target the estrogen signaling axis, have and will continue to be the cornerstone of therapy for patients diagnosed with ER+ disease. Several inhibitors of ER activity exist, including aromatase inhibitors (AIs), selective estrogen receptor modulators (SERMs), selective estrogen receptor degraders/down-regulators (SERDs), and ER proteolysis-targeting chimeras (ER PROTACs); drugs which differ in the mechanism(s) by which they inhibit this signaling pathway. Notwithstanding their significant impact on the management of this disease, resistance to existing endocrine therapies remains a major impediment to durable clinical responses. Although the mechanisms of resistance are complex and varied, dependence on ER is typically retained after progression on SERMs and AIs, suggesting that ER remains a bona fide therapeutic target. The discovery and development of orally bioavailable drugs that eliminate ER expression (SERDs and ER PROTACs) will likely aid in treating this growing patient population. All of the existing endocrine therapies were developed with the intent of inhibiting the cancer cell intrinsic actions of ER and/or with the objective of achieving extreme estrogen deprivation and most achieve that goal. A longstanding question that remains to be addressed, however, is how actions of existing interventions extrinsic to the cancer cells influence tumor biology. We believe that these issues need to be addressed in the development of strategies to develop the next generation of ER-modulators optimized for positive activities in both cancer cells and other cells within the tumor microenvironment (TME).

Identification of the Active Ingredient and Beneficial Effects of Vitex rotundifolia Fruits on Menopausal Symptoms in Ovariectomized Rats

Estrogen replacement therapy is a treatment to relieve the symptoms of menopause. Many studies suggest that natural bioactive ingredients from plants resemble estrogen in structure and biological functions and can relieve symptoms of menopause. The fruit of V. rotundifolia, called "Man HyungJa" in Korean, is a traditional medicine used to treat headache, migraine, eye pain, neuralgia, and premenstrual syndrome in Korea and China. The aim of the present study was to confirm that V. rotundifolia fruit extract (VFE) exerts biological functions similar to those of estrogen in menopausal syndrome. We investigated its in vitro effects on MCF-7 cells and in vivo estrogen-like effects on weight gain and uterine contraction in ovariectomized rats. Using the polar extract, the active constituents of VFE (artemetin, vitexicarpin, hesperidin, luteolin, vitexin, and vanillic acid) with estrogen-like activity were identified in MCF-7 cells. In animal experiments, the efficacy of VFE in ameliorating body weight gain was similar to that of estrogen, as evidenced from improvements in uterine atrophy. Vitexin and vitexicarpin are suggested as the active constituents of V. rotundifolia fruits.

Assessment of in vivo estrogenic and anti-inflammatory activities of the hydro-ethanolic extract and polyphenolic fraction of parsley (Petroselinum sativum Hoffm.)

ETHNOPHARMACOLOGICAL RELEVANCE

Since the dawn of time, medicinal and aromatic plants (AMPs) represent a precious heritage for humanity, especially in developing countries, who exploit their virtues in traditional pharmacopoeia to cope with health problems such as diabetes, kidney stones, ulcer, and digestive disorders. Petroselinum sativum Hoffm. belongs to Apiaceae family. It is traditionally used to treat arterial hypertension, diabetes, cardiac disease, renal disease, and recently reported as a plant endowed with a female anti-infertility effect.

AIM OF THE STUDY

This study aims to evaluate the in vivo effect of hydro-ethanolic extract and polyphenols of Petroselinum sativum Hoffm. on cholesterol, protein and estrogen levels, and characterize the chemical composition of polyphenolic fraction. In addition, acute toxicity and anti-inflammatory activity of tested extract was also investigated.

MATERIALS AND METHODS

Chemical composition of polyphenolic fraction was determined using High-Performance Liquid Chromatography with Diode-Array Detection (HPLC-DAD). First, toxicological investigations including sub-acute toxicity were performed by measuring animals' weights daily for four weeks. Afterwards, histopathological examination of livers and kidneys, and serum assay of ASAT and ALAT were also checked. Next, the acute in vivo anti-inflammatory study of the hydro-ethanolic extract and polyphenols of Petroselinum sativum Hoffm. versus Indomethacin was conducted. Furthermore, we evaluated the estrogenic effect of its hydro-ethanolic extract and the polyphenolic fraction following biochemical assays for the determination of proteins, cholesterol and estrogen levels.

RESULTS

The results revealed the presence of some phenolic compounds mainly ferulic acid, gallic acid and quercetin. Petroselinum sativum Hoffm. extracts also showed no evidence of hepatotoxicity nor nephrotoxicity, with remarkable anti-inflammatory activity, as well as a significant estrogenic effect compared to negative control.

CONCLUSION

This study provides a scope of the potential use of Petroselinum sativum Hoffm. extracts in counteracting female infertility issues.

Anti-osteoporotic effects of alisol C 23-acetate via osteoclastogenesis inhibition

Alismatis rhizoma (AR) is the dried rhizome of Alisma orientale (Sam.) Juz. (Alismataceae). This traditional Chinese formula is diuretic, hypoglycemic, and hypolipidemic. Alisol C 23-acetate (AC23A) from AR is anti-inflammatory and ameliorates certain metabolic diseases. However, the mechanism by which AC23A mitigates osteoporosis is unknown. The present study investigated the anti-osteoporotic effects of AC23A in vivo and in vitro. In an ovariectomized (OVX) rat model, AC23A ameliorated OVX-induced organ coefficients and trabecular bone loss. In OVX rats, AC23A treatment lowered serum TRAP5b, CTK, β-CTX, TNF-α, IL-6, and IL-1β, raised serum E2, and did not significantly change serum OCN or BALP. AC23A inhibited osteoclast formation in a rat co-culture system without affecting osteoblast activity. RANK (receptor activator of nuclear factor kappaB) signaling channels are vital osteoclastogenesis transcription elements. AC23A inhibited RANK ligand (RANKL)-induced TRAP, c-Fos, MMP9, NFATc1, and CTK expression and JNK phosphorylation. Therefore, AC23A is anti-osteoclastogenic in vitro and in vivo by inhibiting RANKL-induced osteoclast differentiation and function. Moreover, AC23A could help prevent or limit osteoclast-mediated bone diseases by inhibiting osteoclastogenesis.

Serendipity in the search for "morning-after pills" led to clomiphene for the induction of ovulation

The approval of the oral contraceptive on June 23, 1960, by the United States Food and Drug Administration (FDA), changed society forever. For the first time, a pill designed and tested by men, supported by influential women, allowed women to control their fertility. For the first time, the FDA approved a medicine to be taken by humans without a disease. The chance discovery of a new group of medicines called nonsteroidal antiestrogens, created an opportunity for the pharmaceutical industry. These compounds were shown to be postcoital antifertility agents in rats and mice. In the 1960s, the development of a "morning-after pill" would have had an enormous market. Numerous companies focused discovery efforts to evaluate the development of their patented nonsteroidal antiestrogens: Merrell (clomiphene), Upjohn (U-11,100A), and ICI Pharmaceutical Division (ICI46,474). However, the antifertility effects of antiestrogens in rats and mice does not mean that the new medicine would be an antifertility agent in women. In this case, clomiphene did exactly the opposite of what it was predicted to prevent. Clomiphene became the first medicine to induce ovulation in subfertile women. This article describes the twists and turns of drug discovery and development over the past half century. The conclusion emphasizes the evolution of drug development over decades, based on fashions in medical research and discoveries in clinical pharmacology. As a result, new uses for old molecules, that started life as "nonsteroidal antiestrogens," have revolutionized women's health as members of the new group of medicines called selective estrogen receptor modulators.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Reproductive Regulation and Oxidative Stress Alleviation of Chinese Herbal Medicine Therapy in Ovariectomised Mouse Model

In Taiwan, the herbal formula B401 is considered as a health supplement for middle-aged women that can alleviate sweating, anxiety, and sleep disorders. However, the relevant mechanisms are still unclear. In this study, we evaluated the beneficial effects of the herbal formula B401 therapy in the reproductive regulation of ovariectomised mice. Female ICR mice were randomised into four groups: wild-type (WT) mice with sham treatment, wild-type mice treated with the herbal formula B401, bilateral ovariectomised (OVX) mice with sham treatment, and bilateral ovariectomised mice treated with the herbal formula B401. Mice were orally given the herbal formula B401 at a dose of 30 mg/kg bw/day for 2 weeks. At the end of oral treatment with sham or the herbal formula B401, levels of reactive oxygen species (ROS), calcium, phosphorus, and estradiol-17β in the blood; uterine weight and endometrial thickness; and expressions of estrogen receptor α (ERα), estrogen receptor β (ERβ), progesterone receptor (PR), vascular endothelial growth factor (VEGF), and superoxide dismutase 2 (SOD2) in the uterine tissue were examined and then compared among the four groups of mice. We found that OVX mice decreased levels of calcium, phosphorus, and estradiol-17β in the blood, decreased uterine weight and endometrial thickness, and decreased expressions of ERα, ERβ, PR, and SOD2 in the uterine tissue but increased blood ROS levels compared with those of WT mice. In addition, OVX mice with the herbal formula B401 therapy can increase levels of calcium, phosphorus, and estradiol-17β in the blood, increase uterine weight and endometrial thickness, and increase expressions of ERα, ERβ, PR, VEGF, and SOD2 in the uterine tissue but decrease blood ROS levels. Our results may provide reasonable explanation for the reproductive regulation of the herbal formula B401 therapy.

The SERM Saga, Something from Nothing: American Cancer Society/SSO Basic Science Lecture

BACKGROUND

The discovery of nonsteroidal antiestrogens created a new group of medicines looking for an application; however, at the time, cytotoxic chemotherapy was the modality of choice to treat all cancers. Antiestrogens were orphan drugs until 1971, with the passing of the National Cancer Act. This enabled laboratory innovations to aid patient care.

METHODS

This article traces the strategic application of tamoxifen to treat breast cancer by targeting the estrogen receptor (ER), deploying long-term adjuvant tamoxifen therapy, and becoming the first chemopreventive for any cancer. Laboratory discoveries from the University of Wisconsin Comprehensive Cancer Center (UWCCC) are described that address a broad range of biological issues with tamoxifen. These translated to improvements in clinical care.

RESULTS

Tamoxifen was studied extensively at UWCCC in the 1980s for the development of acquired resistance to long-term therapy. Additionally, the long-term metabolism of tamoxifen and regulation of growth factors were also studied. A concern with tamoxifen use for chemoprevention was that an antiestrogen would increase bone loss and atherosclerosis. Laboratory studies with tamoxifen and keoxifene (subsequently named raloxifene) demonstrated that 'nonsteroidal antiestrogens' maintained bone density, and this translated into successful clinical trials with tamoxifen at UWCCC. However, tamoxifen also increased endometrial cancer growth; this discovery in the laboratory translated into changes in clinical care. Selective estrogen receptor modulators (SERMs) were born at UWCCC.

CONCLUSIONS

There are now five US FDA-approved SERMs, all with discovery origins at UWCCC. Women's health was revolutionized as SERMs have the ability to treat multiple diseases by switching target sites around a woman's body on or off.

Successful Targeted Therapies for Breast Cancer: the Worcester Foundation and Future Opportunities in Women's Health

The signing of the National Cancer Act in 1971 was designed to take laboratory discoveries rapidly from the bench to the bedside. A "war on cancer" had been declared. Combination cytotoxic chemotherapy was predicted to cure all cancers, based on the stunning success in treating childhood leukemia. Breast cancer treatments were primitive; radical mastectomy and radiation were standard of care for disease that had not spread. Ablative endocrine surgery (oophorectomy, hypophysectomy, and adrenalectomy) was a palliative last option for metastatic breast cancer. However, only 30% responded, surviving for only 1 or 2 years: every patient soon died. The discovery of the estrogen receptor (ER) and translation to breast cancer treatment triggered a revolution in women's health. Two important but interconnected events occurred in 1972 at the Worcester Foundation for Experimental Biology (WFEB) that would exploit the breast tumor ER as the first target to save lives and prevent breast cancer development. Two new groups of medicines-selective ER modulators (SERMs) and aromatase inhibitors (AIs)-would continue the momentum of research at the WFEB to improve women's health. Here, we recount the important progress made in women's health based on knowledge of the endocrinology of breast cancer. We propose future opportunities in SERM therapeutics to "refresh" the current standards of care for breast cancer treatment. The opportunity is based on emerging knowledge about acquired resistance to long-term adjuvant AI therapy used to treat breast cancer.

Treatment of Desmoids and Mesenteric Fibromatosis in Familial Adenomatous Polyposis with Raloxifene

Background

Among the great variety of extracolonic manifestations of familial adenomatous polyposis, the most serious are desmoids and fibromatosis of the abdominal cavity. These may be a danger to the patient and a concern to the clinician. Pharmacological management of this relentless problem is favored by surgical intervention. At present, however, beneficial actions of medical therapy are not separable from undesirable side effects.

Methods

We studied the effects of 120 mg daily of raloxifene, a non-steroidal benzothiophene, on progressive desmoid tumors and mesenteric fibromatosis by evaluation of lesion size and symptoms in 13 patients with familial adenomatous polyposis, selected on the basis of intra-abdominal localization of the lesion, on refractoriness to other medical treatments, and on estrogen receptor-α expression.

Results

The patients had a significant response to raloxifene therapy, with complete remission in 8 cases and partial response in 5 cases, evaluated by regression of symptoms and tumor size. Serum biochemical parameters did not show any significant changes. Side effects were never observed.

Conclusions

Although the number of patients included in the study is limited and in spite of some limitations, the available results support that, in the evaluation of response, daily therapy with raloxifene decreases desmoid tumor and mesenteric fibromatosis size and symptoms and does not cause side effects. These findings offer a novel option in the pharmacological treatment of desmoids, leading to medical therapy of these neoplastic lesions in familial adenomatous polyposis patients.

Mechanochemically induced solid state transformations: The case of raloxifene hydrochloride

Raloxifene hydrochloride is a benzothiophene derivative mainly used in the prevention and treatment of osteoporosis, but exhibits a low bioavailability hindered by its poor water solubility. In this study, a mechanochemical approach based on neat and liquid-assisted grinding was applied to produce new solid forms of raloxifene hydrochloride. The solids obtained were characterized by several solid-state techniques, such as powder X-ray diffraction, thermal analysis, infrared and Raman spectroscopy. These results showed that depending on the processing conditions solvated or amorphous forms can be produced. The thermal stability of the new forms was also investigated showing that the new forms convert back into the raw material form, as observed by Raman spectroscopy, which was successfully used to discriminate amorphous and crystalline forms, as well as, to monitor in situ the recrystallization process. Furthermore, the solubility of the new forms was evaluated, showing the clear advantage of the amorphous form, when compared with the currently marketed salt.

Agonistic activity of tamoxifen, a selective estrogen-receptor modulator (SERM), on arthritic ovariectomized mice

Arthritis is positively associated with the decline of sex hormones, especially estrogen. Tamoxifen (TMX) is a selective estrogen receptor modulator, possessing agonist or antagonistic activity in different tissues. Thus, the objective of this study was to investigate the effect of TMX on the zymosan-induced arthritis model. Female Swiss normal and ovariectomized (OVX) mice were divided into groups and treated for five days with TMX (0.3, 0.9 or 2.7 mg/kg) or 17-β-estradiol (E2, 50 µg/kg). On the fifth day, arthritis was induced and 4 h later, leukocyte migration into joint cavities was evaluated. The neutrophil migration in OVX animals, but not in normal mice, treated with TMX (all tested doses) was significantly decreased compared with mice that received the vehicle (P≤0.05). Similarly, this effect was also demonstrated in the E2-treated group. Therefore, the present study demonstrates that TMX presented agonist effects in inhibiting neutrophil migration and preventing arthritis progression in OVX mice.

Schizandra chinensis exhibits phytoestrogenic effects by regulating the activation of estrogen receptor-α and -β

OBJECTIVE

To investigate the phytoestrogenic effects of Schizandra chinensis (SC) extract by regulating the activation of estrogen receptor.

METHODS

Western blotting assay was performed to investigate the effect of SC extract (1, 10, 100 μg/mL) on the expression of estrogen receptor (ER)-α and -β in MCF-7 human breast cancer cells. Cell viability and the levels of c-fos and c-Jun were analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and Western blot analysis, respectively, to further confirm the anti-cancer effect of SC extract.

RESULTS

SC extract increased the expressions of ER-α and -β (P<0.001), whereas cell viability and the expressions of growth factors (c-fos and c-Jun) were inhibited (P< and <0.001, respectively) following treatment.

CONCLUSIONS

SC extract has phytoestrogenic effects, and its biological action includes ER binding ability with low cancer risk. Therefore, SC might be a potential source for the development of a new alternative to hormone therapy in menopause.

Anabolic therapy with Equisetum arvense along with bone mineralising nutrients in ovariectomized rat model of osteoporosis

Objective:

Equisetum arvense has been used to treat bone diseases. The traditional supplementation of calcium and Vitamin D for osteoporosis patients is insufficient considering the rise in patients every year. We have observed that extending the calcium and Vitamin D supplement with L-lysine, L-proline, L-arginine, and L-ascorbic acid (N) positively affects bone mineralization in ovariectomized rat. Here, we report a further extension of the above supplement with E. arvense.

Materials and Methods:

The changes in serum biomarkers, bone mineral content, and femur bone histology were studied and compared to the standard drug for osteoporosis, namely raloxifene (RAL).

Results:

We report a significant change in formation and resorption markers of bone as well as in cortical bone thickness and trabecular width in N and N + EA groups. The treatment N + EA also restored lipid profile near to normal level compared to ovariectomized group.

Conclusions:

Treatment N + EA was found to be as effective as RAL in reversing the osteoporotic changes.

Protective Effect of 17β-Estradiol Upon Hippocampal Spine Density and Cognitive Function in an Animal Model of Vascular Dementia

The current study examined whether the steroid hormone, 17β-estradiol (E2) can exert long-lasting beneficial effects upon axonal health, synaptic plasticity, dementia-related amyloid-beta (Aβ) protein expression, and hippocampal-dependent cognitive function in an animal model of chronic cerebral hypoperfusion and vascular dementia (VaD). Chronic cerebral hypoperfusion and VaD was induced by bilateral common carotid artery occlusion (BCCAO) in adult male Sprague Dawley rats. Low dose E2 administered for the first 3-months after BCCAO exerted long-lasting beneficial effects, including significant neuroprotection of hippocampal CA1 neurons and preservation of hippocampal-dependent cognitive function when examined at 6-months after BCCAO. E2 treatment also prevented BCCAO-induced damage to hippocampal myelin sheaths and oligodendrocytes, enhanced expression of the synaptic proteins synaptophysin and PSD95 in the hippocampus, and prevented BCCAO-induced loss of total and mushroom dendritic spines in the hippocampal CA1 region. Furthermore, E2-treatment also reduced BCCAO induction of dementia-related proteins expression such as p-tau (PHF1), total ubiquitin, and Aβ1-42, when examined at 6 m after BCCAO. Taken as a whole, the results suggest that low-dose E2 replacement might be a potentially promising therapeutic modality to attenuate or block negative neurological consequences of chronic cerebral hypoperfusion and VaD.

Antiestrogens: structure-activity relationships and use in breast cancer treatment

About 70% of breast tumors express estrogen receptor alpha (ERα), which mediates the proliferative effects of estrogens on breast epithelial cells, and are candidates for treatment with antiestrogens, steroidal or non-steroidal molecules designed to compete with estrogens and antagonize ERs. The variable patterns of activity of antiestrogens (AEs) in estrogen target tissues and the lack of systematic cross-resistance between different types of molecules have provided evidence for different mechanisms of action. AEs are typically classified as selective estrogen receptor modulators (SERMs), which display tissue-specific partial agonist activity (e.g. tamoxifen and raloxifene), or as pure AEs (e.g. fulvestrant), which enhance ERα post-translational modification by ubiquitin-like molecules and accelerate its proteasomal degradation. Characterization of second- and third-generation AEs, however, suggests the induction of diverse ERα structural conformations, resulting in variable degrees of receptor downregulation and different patterns of systemic properties in animal models and in the clinic.

Serum lipidomics analysis of ovariectomized rats under Curcuma comosa treatment

ETHNOPHARMACOLOGICAL RELEVANCE

Curcuma comosa Roxb. (C. comosa) or Wan Chak Motluk, Zingiberaceae family, has been used in Thai traditional medicine for the treatment of gynecological problems and inflammation.

AIM OF THE STUDY

This study aimed to investigate the therapeutic potential of C. comosa by determining the changes in the lipid profiles in the ovariectomized rats, as a model of estrogen-deficiency-induced hyperlipidemia, after treatment with different components of C. comosa using an untargeted lipidomics approach.

MATERIALS AND METHODS

Lipids were extracted from the serum of adult female rats subjected to a sham operation (SHAM; control), ovariectomy (OVX), or OVX with 12-week daily doses of estrogen (17β-estradiol; E₂), (3R)-1,7-diphenyl-(4E,6E)-4,6-heptadien-3-ol (DPHD; a phytoestrogen from C. comosa), powdered C. comosa rhizomes or its crude ethanol extract. They were then analyzed by liquid chromatography-mass spectrometry, characterized, and subjected to the orthogonal projections to latent structures discriminant analysis statistical model to identify tentative biomarkers.

RESULTS

Levels of five classes of lipids (ceramide, ceramide-1-phosphate, sphingomyelin, 1-O-alkenyl-lysophosphatidylethanolamine and lysophosphatidylethanolamine) were elevated in the OVX rats compared to those in the SHAM rats, while the monoacylglycerols and triacylglycerols were decreased. The E₂ treatment only reversed the levels of ceramides, whereas treatments with DPHD, C. comosa extract or powder returned the levels of all upregulated lipids back to those in the SHAM control rats.

CONCLUSIONS

The findings suggest the potential beneficial effects of C. comosa on preventing the increased ceramide levels in OVX rats, a possible cause of metabolic disturbance under estrogen deficiency. Overall, the results demonstrated the power of untargeted lipidomics in discovering disease-relevant biomarkers, as well as evaluating the effectiveness of treatment by C. comosa components (DPHD, extract or powder) as utilized in Thai traditional medicine, and also providing scientific support for its folklore use.

Effects of ospemifene on the female reproductive and urinary tracts: translation from preclinical models into clinical evidence

Objective

Treatment of menopausal symptoms by compounds with tissue-selective estrogen agonist/antagonist effects, often called selective estrogen receptor modulators, has been researched as an alternative to the use of estrogen therapy. These structurally diverse molecules elicit tissue-dependent responses in hormone-responsive tissues and organs, exhibiting variations in estrogenic activity in preclinical models of postmenopausal reproductive tissues that may improve postmenopausal women’s health (eg, prevention and treatment of breast cancer, osteoporosis, and vulvar and vaginal atrophy).

Methods

This literature review investigates whether preclinical data predicted the clinical effects of ospemifene on female reproductive and urinary tract tissues and compares these findings with the specific vaginal effects of other estrogen receptor agonists/antagonists (tamoxifen, raloxifene, and bazedoxifene) in preclinical and clinical studies. Lasofoxifene, although not currently available, is included because of its unique effects on vaginal tissue.

Results

The response of endometrial and vaginal tissues to estrogen receptor agonists/antagonists can be differentiated using transvaginal ultrasound, endometrial histopathology, cytologic examination of vaginal smears, assessment of physical changes in the vagina, and relief of symptoms associated with vulvar and vaginal atrophy (such as dyspareunia).

Conclusions

Available evidence indicates that ospemifene has unique effects on tissue, leading to a favorable long-term profile for the relief of vulvar and vaginal atrophy compared with other estrogen receptor agonists/antagonists (eg, tamoxifen, raloxifene, and bazedoxifene) with no short-term concerns about endometrial safety (based on endometrial hyperplasia, carcinoma, endometrial spotting, and endometrial bleeding).

Ovarian hormones modulate endothelin A and B receptor expression

AIMS

The study aims to determine the modulatory roles of ovarian hormones, estrogen (E2) and progesterone (P), on the expression of endothelin A (ETA) and B (ETB) receptors in lung, liver and kidney tissues.

MAIN METHODS

Female Sprague-Dawley rats were subjected to bilateral ovariectomy and divided into four groups ovariectomized (OVX), OVX+E2, OVX+P, and OVX+E2+P. A separate group of rats underwent sham surgery and served as a control. Three weeks after OVX or sham surgery, tissues from lungs, liver, renal cortex, and inner medulla were collected, snap-frozen, and kept at -80°C for assessment of ETA and ETB receptor expression using real-time PCR.

KEY FINDINGS

E2-treated OVX animals had significantly lower expression of ETA receptors in the lungs, compared to OVX rats. Pulmonary ETB receptor mRNA was not measurably affected by any of the interventions. Hepatic ETA and ETB were significantly increased in OVX+E2+P rats, compared to sham rats. Renal inner medullary ETA and ETB receptor expressions were significantly elevated in OVX compared to sham, an effect that was prevented by co-supplementation of OVX with E2 and P. Additionally, both ETA and ETB receptor expression in the renal cortex were significantly attenuated by ovariectomy, and this reduction was not evident in OVX+E2 rats.

SIGNIFICANCE

These data suggest that ovarian hormones regulate ET receptor expression and may contribute to sex differences in cardiovascular and renal health.

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

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

BF3·Et2O Catalysed 4-Aryl-3-phenyl-benzopyrones, Pro-SERMs, and Their Characterization

We have synthesized the novel 4-(4-hydroxy-benzyl)-3-phenyl-chromen-2-one which is a precursor of SERMs with a smaller number of steps and good yield. Two methodologies for the synthesis have been worked out. Anhydrous BF3·Et2O catalyzed reaction was found to be selective for product formation while anhydrous AlCl3, FeCl3, and SnCl4 catalyzed ones were nonselective.

Is raloxifene associated with lower risk of mortality in postmenopausal women with vertebral fractures after vertebroplasty?: a hospital-based analysis

Background

Osteoporotic fractures are associated with mortality in postmenopausal woman. Whether raloxifen treatment after vertebroplasty can reduce mortality is unclear in this group. To compare the effect of raloxifene and no osteoporosis treatment on the risk of mortality after vertebroplasty, we designed this study.

Methods

This was a retrospective study (January 2001 to December 2007). Follow-up for each participant was calculated as the time from inclusion in the study to the time of death, or to December 31^st, 2013, whichever occurred first. All of the patients underwent baseline bone density studies, and age and body mass index (kg/m²) were recorded. All associated medical diseases such as diabetes, hypertension, and liver and renal disease were recorded.

Results

One hundred and forty-nine patients with vertebral fractures were enrolled, of whom 51 used raloxifene and 98 patients did not receive any anti-osteoporotic therapy. At the end of the follow-up period, 62 patients had died and 87 were still alive. The treated patients had a lower mortality rate than those who did not receive treatment (P = 0.001, HR = 3.845, 95 % CI 1.884-7.845). The most common cause of mortality was sepsis, and those who received raloxifene had a lower rate of sepsis compared to those who did not receive treatment (P < 0.001).

Conclusions

Effective treatment with raloxifene may had a lower mortality rate in patients with postmenopausal osteoporosis-related vertebral fractures after vertebroplasty.

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.

Effects of genistein in combination with conjugated estrogens on endometrial hyperplasia and metabolic dysfunction in ovariectomized mice

Tissue-selective estrogen complex (TSEC), which combines a selective estrogen receptor modulator (SERM) with one or more estrogens, is a novel approach to menopausal therapy. It has been demonstrated that the phytoestrogen genistein (GEN) exhibits mixed estrogen receptor agonist and antagonist activity, suggesting that GEN may have potential for use as a natural SERM. We evaluated, for the first time, the effects of GEN, conjugated estrogens (CE), and their pairing effects as a TSEC treatment on estrogen-induced endometrial hyperplasia and metabolic dysfunction in ovariectomized (OVX) mice fed a high-fat diet. CE replacement prevented fat accumulation in the adipose tissue and liver, improved glucose homeostasis, and induced endometrial hyperplasia in OVX mice. GEN at 100 mg/kg showed CE mimetic effects in preventing ovariectomy-induced metabolic dysfunctions without endometrial stimulation. Combination treatments with CE and GEN prevented metabolic dysfunctions more strongly than CE alone, but at both low and high doses, GEN did not reverse CE-induced endometrial hyperplasia. In addition, we found that in a TSEC regimen, a typical SERM raloxifene maintains the metabolic benefits of CE while simultaneously protecting the endometrium in OVX mice. These findings indicate that GEN acts as an estrogen agonist in metabolic regulation, but has no SERM function in the uteri of OVX mice.

Raloxifene modulates regulators of osteoclastogenesis and angiogenesis in an oestrogen deficiency periapical lesion model

AIM

To analyse the local regulatory mechanisms of osteoclastogenesis and angiogenesis during the progression of periapical lesions in female rats with oestrogen deficiency and treatment with raloxifene (RLX).

METHODOLOGY

Female Wistar rats were distributed into groups: SHAM-veh, subjected to sham surgery and treated with a vehicle; OVX-veh, subjected to ovary removal and treated with a vehicle; and OVX-RLX, subjected to ovary removal and treated with RLX. Vehicle or RLX was administered orally for 90 days. During treatment, the dental pulp of mandibular first molars was exposed to the oral environment for induction of periapical lesions, which were analysed after 7 and 30 days. After the experimental periods, blood samples were collected for measurement of oestradiol, calcium, phosphorus and alkaline phosphatase. The rats were euthanized and the mandibles removed and processed for immunohistochemical detection of receptor activator of nuclear factor kappa-B ligand (RANKL), osteoprotegerin (OPG), hypoxia-inducible factor-1 alpha (HIF-1α) and bone-specific alkaline phosphatase (BALP). Data were compared using Kruskal-Wallis followed by Dunn test (nonparametric values) and anova followed by the Tukey's test (parametric values).

RESULTS

The plasma concentration of oestradiol showed hypo-oestrogenism in the rats subjected to ovary removal. On day 7, alkaline phosphatase activity, calcium and phosphorus were higher in the OVX-RLX group than in the OVX-veh group (P < 0.001), but immunolabelling for RANKL and HIF-1α was lower in OVX-RLX group (P < 0.001). On day 30, the OVX-veh group had higher immunolabelling for RANKL than the OVX-RLX group (P < 0.05). There were no significant differences in the immunoreactivity of OPG and BALP between any groups at either time-point (P > 0.05).

CONCLUSION

RLX therapy reversed the increased levels of the local regulators of both osteoclastogenesis and angiogenesis induced by oestrogen deficiency.

From empirical to mechanism-based discovery of clinically useful Selective Estrogen Receptor Modulators (SERMs)

Our understanding of the molecular mechanisms underlying the pharmacological actions of estrogen receptor (ER) ligands has evolved considerably in recent years. Much of this knowledge has come from a detailed dissection of the mechanism(s) of action of the Selective Estrogen Receptor Modulators (SERMs) tamoxifen and raloxifene, drugs whose estrogen receptor (ER) agonist/antagonist properties are influenced by the cell context in which they operate. These studies have revealed that notwithstanding differences in drug pharmacokinetics, the activity of an ER ligand is determined primarily by (a) the impact that a given ligand has on the receptor conformation and (b) the ability of structurally distinct ER-ligand complexes to interact with functionally distinct coregulators. Exploitation of the established relationships between ER structure and activity has led to the development of improved SERMs with more favorable therapeutic properties and of tissue-selective estrogen complexes, drugs in which a SERM and an ER agonist are combined to yield a blended activity that results in distinct clinical profiles. Remarkably, endogenous ligands that exhibit SERM activity have also been identified. One of these ligands, 27-hydroxycholesterol (27HC), has been shown to manifest ER-dependent pathological activities in the cardiovascular system, bone and mammary gland. Whereas the physiological activity of 27HC remains to be determined, its discovery highlights how cells have adopted mechanisms to allow the same receptor ligand complex to manifest different activities in different cells, and also how these processes can be exploited for new drug development.

The evolution of nonsteroidal antiestrogens to become selective estrogen receptor modulators

The discovery of the first nonsteroidal antiestrogen ethamoxytriphetol (MER25) in 1958, opened the door to a wide range of clinical applications. However, the finding that ethamoxytriphetol was a "morning after" pill in laboratory animals, energized the pharmaceutical industry to discover more potent derivatives. In the wake of the enormous impact of the introduction of the oral contraceptive worldwide, contraceptive research was a central focus in the early 1960's. Numerous compounds were discovered e.g., clomiphene, nafoxidine, and tamoxifen, but the fact that clinical studies showed no contraceptive actions, but, in fact, induced ovulation, dampened enthusiasm for clinical development. Only clomiphene moved forward to pioneer an application to induce ovulation in subfertile women. The fact that all the compounds were antiestrogenic made an application in patients to treat estrogen responsive breast cancer, an obvious choice. However, toxicities and poor projected commercial returns severely retarded clinical development for two decades. In the 1970's a paradigm shift in the laboratory to advocate long term adjuvant tamoxifen treatment for early (non-metastatic) breast cancer changed medical care and dramatically increased survivorship. Tamoxifen pioneered that paradigm shift but it became the medicine of choice in a second paradigm shift for preventing breast cancer during the 1980's and 1990's. This was not surprising as it was the only medicine available and there was laboratory and clinical evidence for the eventual success of this application. Tamoxifen is the first medicine to be approved by the Food and Drug Administration (FDA) to reduce the risk of breast cancer in women at high risk. But it was the re-evaluation of the toxicology of tamoxifen in the 1980's and the finding that there was both carcinogenic potential and a significant, but small, risk of endometrial cancer in postmenopausal women that led to a third paradigm shift to identify applications for selective estrogen receptor (ER) modulation. This idea was to establish a new group of medicines now called selective ER modulators (SERMs). Today there are 5 SERMs FDA approved (one other in Europe) for applications ranging from the reduction of breast cancer risk and osteoporosis to the reduction of menopausal hot flashes and improvements in dyspareunia and vaginal lubrication. This article charts the origins of the current path for progress in women's health with SERMs.

Novel selective estrogen mimics for the treatment of tamoxifen-resistant breast cancer

Endocrine-resistant breast cancer is a major clinical obstacle. The use of 17β-estradiol (E2) has reemerged as a potential treatment option following exhaustive use of tamoxifen or aromatase inhibitors, although side effects have hindered its clinical usage. Protein kinase C alpha (PKCα) expression was shown to be a predictor of disease outcome for patients receiving endocrine therapy and may predict a positive response to an estrogenic treatment. Here, we have investigated the use of novel benzothiophene selective estrogen mimics (SEM) as an alternative to E2 for the treatment of tamoxifen-resistant breast cancer. Following in vitro characterization of SEMs, a panel of clinically relevant PKCα-expressing, tamoxifen-resistant models were used to investigate the antitumor effects of these compounds. SEM treatment resulted in growth inhibition and apoptosis of tamoxifen-resistant cell lines in vitro. In vivo SEM treatment induced tumor regression of tamoxifen-resistant T47D:A18/PKCα and T47D:A18-TAM1 tumor models. T47D:A18/PKCα tumor regression was accompanied by translocation of estrogen receptor (ER) α to extranuclear sites, possibly defining a mechanism through which these SEMs initiate tumor regression. SEM treatment did not stimulate growth of E2-dependent T47D:A18/neo tumors. In addition, unlike E2 or tamoxifen, treatment with SEMs did not stimulate uterine weight gain. These findings suggest the further development of SEMs as a feasible therapeutic strategy for the treatment of endocrine-resistant breast cancer without the side effects associated with E2.

Selective estrogen receptor modulators: tissue specificity and clinical utility

Selective estrogen receptor modulators (SERMs) are a diverse group of nonsteroidal compounds that function as agonists or antagonists for estrogen receptors (ERs) in a target gene-specific and tissue-specific fashion. SERM specificity involves tissue-specific expression of ER subtypes, differential expression of co-regulatory proteins in various tissues, and varying ER conformational changes induced by ligand binding. To date, the major clinical applications of SERMs are their use in the prevention and treatment of breast cancer, the prevention of osteoporosis, and the maintenance of beneficial serum lipid profiles in postmenopausal women. However, SERMs have also been found to promote adverse effects, including thromboembolic events and, in some cases, carcinogenesis, that have proven to be obstacles in their clinical utility. In this review, we discuss the mechanisms of SERM tissue specificity and highlight the therapeutic application of well-known and emergent SERMs.

Treatment with bazedoxifene and conjugated estrogens results in regression of endometriosis in a murine model

Bazedoxifene (BZA), a selective estrogen receptor modulator (SERM), inhibits the action of estrogens on endometrial proliferation. Here, we evaluate the effect of a tissue-selective estrogen complex (TSEC) containing BZA and conjugated estrogens (CE) on ectopic endometrial lesions in a mouse model of endometriosis. Experimental endometriosis was created in 60 female CD-1 mice. The mice were randomly divided into 10 groups that received varying doses of either BZA (1, 2, 3, or 5 mg/kg/day), BZA (1, 2, 3, or 5 mg/kg/day) in combination with CE (3 mg/kg/day), CE treatment alone (3 mg/kg/day), or vehicle control for 8 wk. Treatment with BZA alone or the TSEC containing BZA/CE led to a decrease in endometriotic lesion size compared to controls. The mean surface area of the untreated lesions was 19.6 mm(2). Treatment with BZA or BZA/CE resulted in reduced lesion size (to 8.8 and 7.8 mm(2), respectively). No significant difference was found in lesion size between the BZA and BZA/CE treatment groups or between different doses of either treatment. Ovarian cyst formation was not evident in the treated groups. Treatment with the TSEC containing higher BZA dosages (3 and 5 mg/kg/day) led to significantly lower levels of estrogen receptor (Esr1) mRNA expression compared to the control treatment. No differences were observed in expression of progesterone receptor (Pgr). Immunohistochemical analysis also demonstrated a decrease in ESR protein. The combination of CE and BZA may prove to be a novel treatment option for endometriosis.

Effects of sequential osteoporosis treatments on trabecular bone in adult rats with low bone mass

We used an osteopenic adult ovariectomized (OVX) rat model to evaluate various sequential treatments for osteoporosis, using FDA-approved agents with complementary tissue-level mechanisms of action. Sequential treatment for 3 months each with alendronate (Aln), followed by PTH, followed by resumption of Aln, created the highest trabecular bone mass, best microarchitecture, and highest bone strength.

INTRODUCTION

Individual agents used to treat human osteoporosis reduce fracture risk by ∼ 50-60%. As agents that act with complementary mechanisms are available, sequential therapies that mix antiresorptive and anabolic agents could improve fracture risk reduction, when compared with monotherapies.

METHODS

We evaluated bone mass, bone microarchitecture, and bone strength in adult OVX, osteopenic rats, during different sequences of vehicle (Veh), parathyroid hormone (PTH), Aln, or raloxifene (Ral) in three 90-day treatment periods, over 9 months. Differences among groups were evaluated. The interrelationships of bone mass and microarchitecture endpoints and their relationship to bone strength were studied.

RESULTS

Estrogen deficiency caused bone loss. OVX rats treated with Aln monotherapy had significantly better bone mass, microarchitecture, and bone strength than untreated OVX rats. Rats treated with an Aln drug holiday had bone mass and microarchitecture similar to the Aln monotherapy group but with significantly lower bone strength. PTH-treated rats had markedly higher bone endpoints, but all were lost after PTH withdrawal without follow-up treatment. Rats treated with PTH followed by Aln had better bone endpoints than those treated with Aln monotherapy, PTH monotherapy, or an Aln holiday. Rats treated initially with Aln or Ral, then switched to PTH, also had better bone endpoints, than monotherapy treatment. Rats treated with Aln, then PTH, and returned to Aln had the highest values for all endpoints.

CONCLUSION

Our data indicate that antiresorptive therapy can be coupled with an anabolic agent, to produce and maintain better bone mass, microarchitecture, and strength than can be achieved with any monotherapy.

Effect of Red Clover on CYP Expression: An Investigation of Herb-Drug Interaction at Molecular Level

Hormone replacement therapy and selective estrogen receptor modulator are the most common therapy for women going through menopause. These therapies though popular fail to relieve withdrawal symptoms such as hot flashes, fatigue, leg cramps and nausea. This scenario necessitates to herbal preparations as alternative which may lead to simultaneous intake of herbal preparations, containing flavonoids, as well as Selective estrogen receptor modulator hence creating a phenomenon of herb drug interaction. Here we investigate the effect of red clover on steady state mRNA levels of rat cytochrome P 450 enzymes. Further, red clover's effect on cytochrome P 450's expression has been investigated when co-administered with tamoxifen and raloxifene. Exposure to red clover resulted in significant down regulation of all the cytochrome P 450 isoform mRNA except cytochrome P 450 2C13 and cytochrome P 450 3A2. When red clover is given in combination with tamoxifen or raloxifene altered level of cytochrome P 450 enzyme mRNA is observed. Present results suggest that herbal medical preparations such red clover has potential for herb drug interaction.

The SERM raloxifene improves diaphyseal fracture healing in mice

Although several studies reported that raloxifene treatment improves postmenopausal osteoporotic bone structure and reduces fracture risk, only a few animal and no human studies have examined its effects on the fracture healing process. Thus the aim of the present study was to determine, whether systemic application of the selective estrogen receptor modulator raloxifene promotes fracture healing compared to untreated control-, estrogen-deficient-, as well as estrogen-treated mice using a standardized femoral osteotomy model (n = 60 mice). Ten days after surgery, contact radiography and undecalcified histomorphometric analysis revealed that raloxifene administration significantly improved the early stage of fracture healing compared to all other groups. At day 20, raloxifene and estrogen treatment led to a significant increase in callus mineralization and trabecular thickness compared to control mice. μCT analyses revealed no evidence of complete bony bridging of the fracture site in any control-, nor estrogen-deficient mouse after 20 days, while all femoral fractures in the raloxifene and estrogen group already healed adequately at this time. These data indicate that raloxifene treatment significantly improves all phases of fracture healing at least in mice. Therefore, raloxifene could be a possible pharmaceutical to enhance fracture healing in women, without the known side effects of estrogen.

Characterization of raloxifene glucuronidation: potential role of UGT1A8 genotype on raloxifene metabolism in vivo

Raloxifene is a second-generation selective estrogen receptor modulator used for the prevention and treatment of osteoporosis and the prevention of breast cancer in postmenopausal women. Raloxifene is extensively metabolized by glucuronidation to form raloxifene-6-glucuronide (ral-6-Gluc) and raloxifene-4'-glucuronide (ral-4'-Gluc). The goal of the present study was to determine whether functional polymorphisms in active UGTs could play a role in altered raloxifene glucuronidation in vivo. Using homogenates from HEK293 UGT-overexpressing cell lines, raloxifene was shown to be glucuronidated primarily by the hepatic UGTs 1A1 and 1A9 and the extra-hepatic UGTs 1A8 and 1A10; no detectable raloxifene glucuronidation activity was found for UGT2B enzymes. Functional UGT1A1 transcriptional promoter genotypes were significantly (Ptrend = 0.005) associated with ral-6-Gluc formation in human liver microsomes, and, consistent with the decreased raloxifene glucuronidation activities observed in vitro with cell lines overexpressing UGT1A8 variants, the UGT1A8*2 variant was significantly (P = 0.023) correlated with total raloxifene glucuronide formation in human jejunum homogenates. While ral-4'-Gluc exhibited 1:100th the anti-estrogenic activity of raloxifene itself as measured by binding to the estrogen receptor, raloxifene glucuronides comprised about 99% of the circulating raloxifene dose in raloxifene-treated subjects, with ral-4'-Gluc comprising ~70% of raloxifene glucuronides. Plasma ral-6-Gluc (Ptrend = 0.0025), ral-4'-Gluc (Ptrend = 0.001), and total raloxifene glucuronides (Ptrend = 0.001) were increased in raloxifene-treated subjects who were predicted slow metabolizers [UGT1A8 (*1/*3)] versus intermediate metabolizers [UGT1A8 (*1/*1) or UGT1A8 (*1/*2)] versus fast metabolizers [UGT1A8 (*2/*2). These data suggest that raloxifene metabolism may be dependent on UGT1A8 genotype and that UGT1A8 genotype may play an important role in overall response to raloxifene.