Raloxifene Treatment Research Articles

Oxidative Stress and Raloxifene

Dear Editor, We read “Effects of raloxifene on bone metabolism in hemodialysis patients with type 2 diabetes” by Saito et al. (1) with a great interest. This paper shows that raloxifene works in diabetic or non-diabetic hemodialysis patients to reduce bone loss. This was shown by means of significant decrease in NTx and a significant increase in SOS measurements in both treatment groups compared to the un-treated control arms. We would like to draw attention to the possible anti-oxidant role of raloxifene regarding beneficial effects on the bone turnover markers as well as bone mass. The targeted population in this study consisted hemodialysis patients with type 2 diabetes who under a great oxidative stress related to both renal failure and diabetes (2, 3). We have previously demonstrated that women with post-menopausal osteoporosis had lower erythrocyte catalase (CAT) enzyme activity and higher erythrocyte malondialdehyde (MDA) levels (4). Interestingly, in another study we showed that raloxifene treatment for 3 months significantly enhanced CAT enzyme activity and reduced the MDA levels in women with PMO (5). Similar anti-oxidant effects of raloxifene were confirmed by others (6). Although neither discussed nor studied by means of enzymatic parameters, we would like to attract Authors’ attention to the potent anti-oxidant effect of raloxifene particularly in this special study population. Significant decrease in N-terminal cross-linking telopeptide of type I collagen (NTx) as well as oxidative stress parameters has been achieved with the use of potent anti-oxidants (lycopene) in patients with PMO (7). We think the results of this present study should also be admissible regarding the anti-oxidant effects of raloxifene particularly in hemodialysis patients with type 2 diabetes who are under great oxidative stress.

Successful use of adjuvant raloxifene treatment in clozapine-resistant schizophrenia

Successful use of adjuvant raloxifene treatment in clozapine-resistant schizophrenia

Restoration of Endothelial Function via Enhanced Nitric Oxide Synthesis after Long-term Treatment of Raloxifene in Adult Hypertensive Rats

Raloxifene (CAS 84449-90-1, RAL), a selective estrogen receptor modulator (SERM) effective for the prevention of post-menopausal osteoporosis, also has been shown to acutely stimulate nitric oxide (NO) synthesis associated with improved endothelium-dependent relaxation. The effect of a 3-month RAL treatment (10 mg/kg/d) on basal blood pressure, measured via the carotid artery, and its challenge with increasing doses of intravenous bradykinin (1, 3 and 10 nmol/kg) was investigated. Furthermore, aortic NO bioavailability and relaxation in 9-month-old male and female ovarectomized (OVX) spontaneously hypertensive rats (SHR) was tested. Calcium ionophore stimulated NO release from aortic endothelial cells and aortic superoxide (O2-) production was directly assessed by using electrochemical nanosensors. Relaxation studies were performed with acetylcholine (10(-8) to 10(-5) mol/L) following precontraction with phenylephrine (10(-7) mmol/L). Whereas basal blood pressure (BP) was not significantly decreased in RAL treated SHR, the dose-dependent challenge with bradykinin induced an enhanced BP reduction in either gender. In contrast to female animals, aortic segments from RAL treated male animals showed significantly improved relaxaSHR) to 360 +/- 15 nmol/L. Vice versa, O2- was decreased from 110 +/- 15 to 22 +/- 1 nmol/L. In female SHR, ovarectomy led to an increase/decrease of NO/O2- from 130 +/- 5 to 180 +/- 10 nmol/L and 82 +/- 7 to 68 +/- 3 nmol/L, respectively. These effects were significantly amplified by RAL treatment (NO: 370 +/- 10 and O2-: 25 +/- 2 nmol/L). The results show that long-term treatment with RAL has beneficial affects on the cardiovascular system in old male and female OVX SHR via an increased NO bioavailability.

P2-08-01: Impact of Aromatase Inhibitors on Background Parenchymal Enhancement and Amount of Fibroglandular Tissue on Breast MRI.

Abstract Background: On breast MRI, background parenchymal enhancement (BPE) and volume of fibroglandular tissue (FGT) have been shown to reflect a patient's hormonal status. Tamoxifen has been shown to reduce mammographic breast density and may serve as an early predictor of response in the prevention setting (Cuzick, JNCI 2011). We have shown that adjuvant tamoxifen can reduce BPE in the unaffected breast in women with breast cancer. We hypothesize that aromatase inhibitor (AI) induced endocrine changes in breast tissue should also be evident and therefore we performed a study to evaluate whether adjuvant AI therapy influences BPE or amount of FGT in the contralateral breast. Methods: An electronic medical record review identified 856 postmenopausal women with stage I-III breast cancer who had at least two breast MRIs and took adjuvant AI treatment. A retrospective chart review was conducted to select those patients without a history of prior tamoxifen or raloxifene treatment who had a MRI of the contralateral breast both before and during 6 to 12 months of AI treatment. After exclusion of all irradiated breasts, 168 women were eligible. MRIs were performed between August 1999 and June 2010. Two radiologists who were blind to AI treatment status, independently rated level of BPE and amount of FGT using categorical scales: BPE — Minimal, Mild, Moderate, Marked; FGT — Fatty, Scattered, Heterogeneously Dense, Dense (based on proposed BIRADS criteria for BPE and on ACR criteria for FGT). Blinded side-by-side direct comparison evaluated whether there was a category change between the two MRIs. A consensus was reached in cases of disagreement. The Wilcoxon signed-rank test was used to assess changes in rating categories for BPE and FGT between before and during AI breast MRIs. A waiver of authorization was granted by the institutional review board for this study. Results: In this study 127/168 (76%) women were treated with anastrozole, 33/168 (20%) with letrozole and 8/168 (5%) with exemestane. Based on the blinded side-by-side comparison, a category (or more) decrease in BPE occurred during treatment with AIs (p<0.0001). There was an overall shift from higher to lower degree of BPE in 35% (45/127) of the women taking anastrozole while a category increase occurred in only one woman (1%; p <0.0001). A similar result was seen in the women taking letrozole [45% (15/33) had a decrease versus 3% (1/33) an increase; p=0.0003] and exemestane [25% (2/8) had a decrease versus 12.5% (1/8) an increase; p=0.50]. For FGT a category decrease occurred in 5% (6/127) of anastrozole users while no increase occurred [0% (0/127), p=0.016]. The respective numbers for letrozole were 3% (1/33) and 0% (0/33), and nobody on exemestane had a change in FGT. Conclusions: After 6 to 12 months of treatment with adjuvant AIs, there was a statistically significant category (or more) decrease in BPE. BPE is more sensitive than FGT to changes in normal breast stroma that occur during adjuvant treatment with AIs and BPE may be a marker of anti-hormonal activity in the breasts. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-08-01.

Non-classical estrogen receptors action on human dermal fibroblasts

Objective To study the possible non-genomic effect of selective estrogen receptor modulators on human dermal fibroblasts (HDF). Materials and Methods WS1 cells were used to test the effect of raloxifene. The mRNA expressions of estrogen receptor (ER) α and β and G protein-coupled ER 1(GRP30) were examined by reverse transcription polymerase chain reaction. Apoptosis was identified by TUNEL assay and FACS analysis. MAPK and PI3 K/Akt pathways were determined by immunoblotting analysis. Results Neither ERα nor ERβ, but GPR30 was detected in WS1 cells. Raloxifene increased apoptosis, which was blocked by pertussis toxin, an inhibitor of G protein, or by LY294002. Phosphorylated p38 MAPK and Akt were also increased after raloxifene treatment. Conclusion SERMs could induce apoptosis of HDF through G protein and PI3 K/Akt signaling, which may help understand the role of SERMs on the skin.

Raloxifene improves vascular reactivity in pressurized septal coronary arteries of ovariectomized hamsters fed cholesterol diet

Although vascular effects of selective estrogen receptor modulators (SERMs) have been extensively examined in conduit arteries, whether SERMs could favorably modulate myogenic response in resistance arteries is unknown. The impact of raloxifene therapy and cholesterol diet on myogenic constriction during estrogen deficiency is unresolved. This study investigated changes in vascular reactivity and myogenic responses in female ovariectomized (Ovx) hamsters fed high-cholesterol diet (HCD) with and without chronic treatment of raloxifene. Functional studies were performed on hamster septal coronary arteries cannulated in a pressure myograph. Acetylcholine (ACh)-induced dilatation was reduced in arteries from cholesterol-fed Ovx hamsters, but not in those from cholesterol-fed hamsters, while pressure-induced myogenic constriction was unaffected. Chronic treatment with raloxifene restored ACh-induced dilatation in cholesterol-fed Ovx hamsters. U46619-induced constriction was increased in arteries from cholesterol-fed Ovx hamsters but not from cholesterol-fed control hamsters, which was normalized by chronic raloxifene treatment. The pressure–diameter relationship is presented as normalized diameter versus intraluminal pressure, while the effect of ACh or U46619 is expressed as percentage of tone at 80mmHg. Two-way analysis of variance (ANOVA) followed by Bonferroni post-tests were used for statistical evaluation among different treatment groups. P<0.05 was taken as statistically significant. The present results show that chronic treatment with raloxifene could benefit myogenically active coronary arteries by (i) restoring ACh-induced dilatation and (ii) reducing U46619-induced constriction without affecting pressure-induced myogenic responses in cholesterol-fed hamsters during estrogen deficiency. If such benefit can be observed in humans, raloxifene and other SERMs may be useful to preserve endothelial function and curtail vascular hypersensitivity in resistance coronary arteries in post-menopausal women with hypercholesterolemia or hyperlipidemia, a lipid condition implicated in the pathogenesis of myocardial infarction.

Effects of Raloxifene on Bone in Patients With Type 2 Diabetes

Dear Editor, Raloxifene, one of selective estrogen receptor modulators, has been widely prescribed to relatively early postmenopausal women with osteoporosis and osteopenia since postmenopausal women on hormone therapy (HT) stopped the medication, and the number of postmenopausal women starting HT decreased, mainly because of the increased risks of breast cancer and cardiovascular diseases after the Women’s Health Initiative (WHI) report (1). Saito et al. showed that reduction in BMD in postmenopausal dialysis women both with and without type 2 diabetes was suppressed by raloxifene therapy, indicating raloxifene treatment is useful and could be a possibility for women with type 2 diabetes (2). Before we reach the conclusion, I am afraid that there might be some problems that have to be made clear although the trial was well organized. First, the number of subjects is very small (100 or fewer). Second, the subjects are rather early postmenopausal women (range: 50-87 years). The criteria of postmenopausal status were not defined. Third, do 19 diabetic subjects on diet therapy alone really need hemodialysis? Fourth, the values of HbA1c are not shown in non-diabetic group. Fifth, the speed of sound (SOS) does not measure BMD although the SOS has been shown to be significantly correlated with lumbar BMD. Finally, the changes in serum Ca, P, intact PTH (i-PTH) and BAP have not been evaluated in the text. We have recently shown that raloxifene alone could induce a significant increase in circulating i-PTH, which might diminish the beneficial effect of raloxifene on BMD, and that the addition of alfacalcidol to raloxifene demonstrated a greater bone sparing effect by normalizing serum i-PTH level than raloxifene alone therapy in postmenopausal Japanese women with osteoporosis or osteopenia (3). In our study i-PTH significantly increased and corrected serum calcium significantly decreased at 6 month and thereafter in subjects on raloxifene alone therapy, which might be caused by inhibition of bone resorption. Our result is not in agreement with the reports that raloxifene lowered serum PTH in postmenopausal women with osteoporosis (4) and that raloxifene did not affect PTH levels in those with primary hyperparathyroidism (5) although serum calcium decreased in both studies. However the authors did not mention whether raloxifene has any effects on i-PTH secretion and serum Ca, i-PTH in diabetic patients was lower than in non-diabetic patients after one year. As shown in tables 1 and 2 (2), i-PTH levels decreased one year after raloxifene therapy (54.7 ng/L) in diabetic subjects compared to control (71.9 ng/L) or baseline (78.2 ng/L), suggesting that raloxifene might have some influences on i-PTH secretion, possibly suppressing i-PTH secretion where hemodialysis patients have secondary hyperparathyroidism. In contrast, corrected serum Ca levels did not change remarkably after raloxifene therapy (2.27 mmol/L) vs. control (2.13 mmol/L) or baseline (2.22 mmol/L). The discrepancy between this study and our study could be explained by the difference in vitamin D status of the subjects; in this study vitamin D is co-administered (vitamin D replete) whereas in our study it is not (vitamin D insufficiency or deficiency), suggesting that raloxifene might exert its inhibitory effect on PTH secretion only when vitamin D status is replete or sufficient. In any way this study shows that raloxifene therapy could be useful in postmenopausal dialysis patients both with and without type 2 diabetes.

A postmenopausal woman developed a giant endometrial polyp during Raloxifene treatment

Raloxifene is a selective oestrogen receptor modulator approved for the prevention of osteoporosis in high risk patients. The drug has a good safety record with regard to endometrium, breast and ca...

Are Physicians Ready to Prevent Osteoporotic Fractures in Hemodialysis Patients?

Dear Editor, Chronic kidney disease (CKD) is associated with many adverse outcomes including mineral and bone disorders. The prevalence of fractures among patients with CKD exceeds that of the general population, due to impairments in bone quantity, bone quality, and abnormalities of neuromuscular function with profound effects on morbidity and mortality (1). Type 2 diabetes mellitus (T2DM), that is a major cause of CKD, appears per se associated with an increased fracture risk despite a higher bone mineral density (BMD). The heavy burden of fractures in T2DM is much more due to poor bone quality than BMD, and bone quality is not detected by common diagnostic tools such as dual energy X-ray absorptiometry (2). Little is known about the efficacy of antiosteoporotic drugs in subjects undergoing hemodialysis, as these patients are often excluded in large randomized controlled trials. Raloxifene, a selective estrogen receptor modulator, prevents bone loss in postmenopausal women and reduces risk of vertebral fracture (3). Although the effects on bone density and biochemical markers were about half those observed in women treated with alendronate, the reduction in vertebral fracture risk was similar to alendronate, suggesting that other factors, beyond BMD, contribute to prevention of fractures. Saito et al. have recently reported the effects of one year raloxifene treatment on bone metabolism in hemodialysis women with and without T2DM (4). Data from Saito et al. evidence a significant increase of bone density evaluated by calcaneal quantitative ultrasound and a slight not significant reduction of the bone resorption marker NTx, both in T2DM and non T2DM women treated with raloxifene. Raloxifene is metabolized in the liver, and the resulting glucuronides are excreted in the bile, thus CKD is expected not to affect the pharmacokinetics of raloxifene. Hemodialysis patients with T2DM usually show low bone turnover rate, therefore raloxifene, that is only a mild bone resorption inhibitor seems a valid choice. Raloxifene, differently from hormone replacement therapy (HRT), reduces also the incidence of breast cancer, but, as to HRT, increases the incidence of venous thromboembolic events, thus caution is advised for the treatment of patients with high cardiovascular risk such as in CKD. Moreover, data on the possible effects of raloxifene on the insulin-glucose homeostasis are few, but raloxifene does not significantly affect glycemic control (5). The longer life expectancy obtained through hemodialytic programs in patients with CKD, should encourage researchers to look forward to bone health and reduction of the fracture risk. Unfortunately, to date, there are limited data on fracture risk assessment and fracture preventions with antiosteoporotic drugs in the hemodialytic population. What has been shown by Saito et al. on surrogate markers of bone strength (BMD and bone turnover) is encouraging for further prospective intervention studies to verify the long term safety and antifracture efficacy of raloxifene in T2DM hemodialysis patients.

The effect of raloxifene on telomerase expression in breast carcinoma samples from postmenopausal women

ObjectiveThis study aims to evaluate the effect of raloxifene on the expression of human telomerase reverse transcriptase (hTERT) in invasive ductal breast carcinoma of postmenopausal women. Study designThis study included 20 postmenopausal women with invasive, stage II, estrogen receptor-positive ductal carcinoma diagnosed by incisional biopsy, who received 60mg of raloxifene orally for 28 days prior to definitive surgery. On the 29th day of treatment, definitive surgery was performed and a second tumor sample was taken for analysis. The catalytic subunit of telomerase (hTERT) was evaluated semiquantitatively by immunohistochemistry in the tumor samples obtained prior to and following raloxifene use and the results were analyzed using the McNemar test (p<0.05). ResultsThe samples of 17 patients (85%) were classified as positive for telomerase expression prior to raloxifene treatment, while only 6 (30%) remained positive following raloxifene treatment (p<0.0026). ConclusionIn the present study, raloxifene significantly reduced the expression of hTERT in estrogen receptor-positive breast tumors from postmenopausal women.

Osteoporosis Treatment: An Evidence-Based Approach

Osteoporosis is a disease that results in decreased bone mass and quality of bone, which may lead to fracture. Clinicians need to counsel individuals on appropriate intake of calcium and vitamin D, increasing weight-bearing exercise, limiting alcohol and caffeine, and avoiding smoking. A variety of nonhormonal pharmacological options are available for prevention and treatment of osteoporosis, including bisphosphonates, calcitonin (Miacalcin®), raloxifene (Evista®), teriparatide (Forteo®), and denosumab (Prolia®). The National Osteoporosis Foundation and the American Association of Clinical Endocrinologists have recently published new guidelines, and it is important for clinicians to be familiar with the evidence behind each of these treatment modalities. It is paramount for nurses to make evidence-based, cost-effective decisions about pharmacological therapy based on individual patient-specific factors.

Long-term treatment with raloxifene, but not bisphosphonates, reduces circulating sclerostin levels in postmenopausal women

We determined whether suppression of sclerostin levels by estrogen treatment was mediated by anti-resorptive effect. Raloxifene, but not bisphosphonates, suppressed circulating sclerostin concentration, suggesting that sclerostin may mediate the action of estrogen on bone metabolism, independently of their anti-resorptive effects. Circulating sclerostin concentrations are higher in postmenopausal than in premenopausal women, and estrogen treatment suppresses sclerostin levels in both men and women. We determined whether anti-resorptives may suppress the circulating sclerostin levels. We conducted a retrospective observational study. Eighty postmenopausal women were treated with raloxifene for 19.4 ± 7.7 months (n = 16), bisphosphonates for 19.2 ± 6.7 months (n = 32), or were untreated (n = 32) for 17.1 ± 4.6 months. Plasma sclerostin concentrations were measured before and after treatment. Plasma sclerostin levels after treatment were significantly lower in the raloxifene than in the control group (55.8 ± 23.4 pmol/l vs. 92.1 ± 50.4 pmol/l, p = 0.046), but were similar between the bisphosphonate and control groups. Relative to baseline, raloxifene treatment markedly reduced plasma sclerostin concentration (-40.7 ± 22.8%, p < 0.001), with respect to both control (-7.5 ± 29.1%) and bisphosphonate (-3.1 ± 35.2%) groups. Changes in bone-specific alkaline phosphatase and osteocalcin levels showed reverse associations with sclerostin concentration changes in the raloxifene (γ = -0.505, p = 0.017) and control (γ = -0.410, p = 0.020) groups. Raloxifene, but not bisphosphonates, significantly suppressed circulating sclerostin concentration, suggesting that sclerostin may mediate the action of estrogen on bone metabolism, independently of their anti-resorptive effects.

Efecto del raloxifeno en la función endotelial y la hemostasia en mujeres con enfermedad coronaria

Introduction and objectives Modulation of vascular tone is one of the most relevant estrogen effects. A beneficial effect on endothelial function in postmenopausal women has also been proposed for the selective estrogen receptor modulator raloxifene. However, its effects in women with established cardiovascular disease have not been fully elucidated. In addition, recent trials have generated controversy regarding thromboembolic risk with raloxifene use. The aim of the study was to assess the effect of raloxifene on: a) endothelial function and b) coagulation and fibrinolysis pathways. Methods The MERCED trial was a prospective, randomized clinical trial. Thirty-three postmenopausal women with ischemic heart disease were enrolled in the study. Raloxifene treatment was administered for a 3-month period, according to a double-blind crossover design. Assessment of vascular function and biologic parameters related to coagulation pathways were conducted at various pre-established time-points. Results Flow-mediated dilatation was severely impaired in the study population, and raloxifene had no effect on endothelial function. Treatment with raloxifene was associated to decreased levels of fibrinogen (3.41 [3.11-3.74] vs. 3.69 [3.40-4.00], P < .05); prothrombin fragments F 1+2 (0.93 [0.77-1.12] vs. 0.94 [0.78-1.15], P < .05); and plasmin/antiplasmin complexes (211 [166-267] vs. 242 [199-295], P < .01). Conclusions The present study provides evidence that in postmenopausal women with demonstrated endothelial dysfunction and ischemic heart disease, mid-term treatment with raloxifene does not affect endothelial function. In the MERCED trial, no increased thrombotic risk was observed, but a decreased thrombotic and fibrinolytic activity was observed with raloxifene. Further studies are required to determine whether thrombotic risk is associated with specific clinical characteristics or subgroups of postmenopausal women with cardiovascular disease. Full English text available from: www.revespcardiol.org

Effects of Raloxifene on Endothelial Function and Hemostasis in Women With Ischemic Heart Disease

Introduction and objectives Modulation of vascular tone is one of the most relevant estrogen effects. A beneficial effect on endothelial function in postmenopausal women has also been proposed for the selective estrogen receptor modulator raloxifene. However, its effects in women with established cardiovascular disease have not been fully elucidated. In addition, recent trials have generated controversy regarding thromboembolic risk with raloxifene use. The aim of the study was to assess the effect of raloxifene on: a) endothelial function and b) coagulation and fibrinolysis pathways. Methods The MERCED trial was a prospective, randomized clinical trial. Thirty-three postmenopausal women with ischemic heart disease were enrolled in the study. Raloxifene treatment was administered for a 3-month period, according to a double-blind crossover design. Assessment of vascular function and biologic parameters related to coagulation pathways were conducted at various pre-established time-points. Results Flow-mediated dilatation was severely impaired in the study population, and raloxifene had no effect on endothelial function. Treatment with raloxifene was associated to decreased levels of fibrinogen (3.41 [3.11-3.74] vs. 3.69 [3.40-4.00], P < .05); prothrombin fragments F 1+2 (0.93 [0.77-1.12] vs. 0.94 [0.78-1.15], P < .05); and plasmin/antiplasmin complexes (211 [166-267] vs. 242 [199-295], P < .01). Conclusions The present study provides evidence that in postmenopausal women with demonstrated endothelial dysfunction and ischemic heart disease, mid-term treatment with raloxifene does not affect endothelial function. In the MERCED trial, no increased thrombotic risk was observed, but a decreased thrombotic and fibrinolytic activity was observed with raloxifene. Further studies are required to determine whether thrombotic risk is associated with specific clinical characteristics or subgroups of postmenopausal women with cardiovascular disease.

Effects of Raloxifene on Bone Mineral Metabolism in Postmenopausal Japanese Women on Hemodialysis

In addition to renal osteodystrophy, postmenopausal women on hemodialysis are at high risk for osteoporosis. Recent studies reported the effects of raloxifene, a selective estrogen receptor modulator for osteoporosis, in postmenopausal women. The present study evaluated the efficacy of raloxifene and its effects on bone mineral metabolism in postmenopausal Japanese patients on dialysis. In a prospective, multicentre study, 17 postmenopausal women on chronic hemodialysis with severe osteoporosis (bone mineral density [BMD]≤2 SD by bone densitometry) were treated with 60 mg/day raloxifene hydrochloride for 12 months. The study also included 10 age-matched control women. Vitamin D and calcium salts were not changed during the study. Intact parathyroid hormone (iPTH), serum calcium and phosphorus, and bone resorption marker (NTx) were measured, and BMD were determined by DEXA, at 0, 6, and 12 months after administration of raloxifene. The mean lumbar spine BMD at baseline was similar in the two groups. Raloxifene therapy (for 12 months) improved lumbar spine BMD (by 2.6%) in 53% of the patients, while 70% of the control group showed a reduction in BMD (by 4.0%). Raloxifene significantly decreased serum calcium and increased iPTH. Our results suggested that raloxifene improved trabecular BMD in postmenopausal Japanese women on hemodialysis. The effects of raloxifene on serum calcium and serum iPTH level suggest it improves bone resorption. Vitamin D and/or calcium salts should be added to raloxifene treatment to avoid secondary hyperparathyroidism.

Expression of Ki-67 and Bcl-2 biomarkers in normal breast tissue from women of reproductive age treated with raloxifene

To evaluate the effect of raloxifene on antigen expression of Ki-67 and Bcl-2 in normal breast tissue. A randomized, double-blind study was conducted with 40 premenopausal women aged 18-40years who had been diagnosed with fibroadenoma of the breast. The patients were divided into two groups: Group A (placebo, n=20), and Group B (raloxifene 60mg, n=20).The medication was taken for 22days initiating from the first day of the menstrual cycle. An excisional biopsy was performed on the 23rd day. At the time of biopsy, a sample of normal breast tissue was collected to evaluate protein expression of Ki-67 and Bcl-2. The Student's t test and Chi-square test were used for statistical data analysis and the significance level was established at 5%. The mean percentage of nuclei stained for Ki-67 was 22.16±1.91 (p<0.001) and 2.161±0.181 in the control group and the raloxifene group. The expression of Bcl-2 was similar in both groups (p=0.8888). Raloxifene treatment significantly reduced antigen expression of Ki-67, but failed to have any significant results on the Bcl-2 expression. Further studies are warranted to evaluate the mechanism of raloxifene on apoptosis in normal breast tissue.

Abstract 831: Chemopreventive effects of selective estrogen receptor modulator (SERM) raloxifene on intestinal neoplasia of APCMin/+ mice

Abstract Estrogen receptor β (ER-β) has been implicated in several neoplastic diseases. Previously we have shown that ER-β is up-regulated in human and rodent colonic tumors, suggesting ER-β as a potential target for colon cancer prevention (Naveena et al., CaPR 2009). Thus, ER-β modualtors, SERMs are useful for colon cancer prevention. Hence, we tested raloxifene, an ER antagonist in APCMin/+ mice treated with azoxymethane (AOM), to enhance the colonic tumors. Six-week-old male and female APCMin/+ (9/group) were injected s.c., with AOM at 5 mg/kg BW, once a week for three weeks. APCMin/+ mice were then fed diets containing 0, 1.5, and 3.0 ppm raloxifene for 12 weeks before intestinal tumors and various markers of toxicity, cell proliferation and apoptosis were evaluated. Results suggest that dietary administration of 1.5 and 3.0 ppm raloxifene in male mice suppressed small intestinal polyp formation by 24% (p&amp;lt;0.05) and 58% (p&amp;lt;0.0001), respectively. In female mice, 1.5 and 3.0 ppm raloxifene suppressed small intestinal polyps by 58% (0&amp;lt;0.0001) and 48% (p&amp;lt;0.0001), respectively. Also, significant inhibition of colonic tumor suppression was observed in female mice fed the 1.5 and 3.0 ppm of raloxifene, whereas in male mice, only high-dose inhibited colonic tumors. Mice fed with raloxifene had &amp;gt;70% less polyps with size of &amp;gt;1-mm suggesting suppression of tumor volume/size. Also, we find that raloxifene treatment in female APCMin/+ mice showed significantly reduced serum creatine phosphokinase and cholesterol levels, and an increased alkaline phosphatase levels when compared to untreated control mice. Also, a dose-dependent increase in serum calcium was observed with raloxifene administration. Dietary raloxifene showed no liver enzyme toxicities as measured by aspartate aminotransferase levels in serum. However, raloxifene administered mice showed a modest decrease in serum glucose levels. The mRNA and protein expression levels for p21cip/waf1 were significantly higher with decreased expression of Cyclin D1 and PCNA in raloxifene treated colonic tumors and SI polyps compared to control diet fed mice tissues, suggesting estrogen's function in crypt cell proliferation. Overall, our results clearly suggest that raloxifene significantly suppresses small intestinal and colonic polyps formation by up-regulating p21cip/waf1 and has potential usefulness for human colon cancer prevention. (Supported by CN53300 and R01-94962) Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 831. doi:10.1158/1538-7445.AM2011-831

Raloxifene induces cell death and inhibits proliferation through multiple signaling pathways in prostate cancer cells expressing different levels of estrogen receptorα and β

Raloxifene (RAL), a selective estrogen receptor (ER) modulator (SERM) seems to induce apoptosis in both androgen-dependent and -independent prostate cell (PC) lines via activation of ERβ and an antagonistic effect on ERα. In this study, we evaluated the effects of RAL on epithelial PC growth using the two following in vitro models: the androgen-dependent cell line EPN which expressed both ERs; and a stabilized epithelial cell line derived from a prostate cancer specimen (CPEC), which expressed low levels of ERβ and lacked ERα. In EPN cells, there was an increase in the pre-G1 apoptotic peak and a reduction in the S phase of the cell cycle with G0/G1 arrest after E2 or RAL treatment; bcl-2 mRNA and Bcl-2 protein levels were significantly reduced, while activated caspase-3 and Par-4 levels increased significantly after either E2 or RAL treatment; in addition, c-myc transcript was inhibited after 10(-6) M RAL treatment. A dose-dependent increase of metallothionein II gene RNA level was also induced by RAL in EPN. In CPEC, there was only a weak apoptotic peak associated with caspase-3 activation and Par-4 increase after either E2 or RAL treatment; while c-myc transcript level increased. RAL induced a rapid but transient phosphorylation of ERK 1/2 in EPN cells but generated a sustained effect in CPEC. These findings suggest that RAL effects on PC growth control in vitro are cell-specific, depending on ERβ or ERβ/ERα relative expression levels. Moreover, this study demonstrated that RAL affected both transcriptional regulation and non-genomic signals, which resulted in the modulation of multiple signaling pathways of apoptosis and of cell cycle progression.

Treatment of osteoporosis and reduction in risk of invasive breast cancer in postmenopausal women with raloxifene

Introduction: Raloxifene, a non-steroidal selective estrogen receptor modulator (SERM), offers a new dimension for the treatment and prevention of osteoporosis and risk reduction of invasive breast cancer in postmenopausal populations at high risk. Both osteoporosis and breast cancer are important public health issues for postmenopausal women. It is well known that estrogen and estrogen receptors play an important role in the pathogenesis of both diseases. Initially, hormone replacement therapy (HRT) was used for the purpose of preventing and treating postmenopausal osteoporosis. However, HRT significantly contributed to an increase in breast cancer risk. The SERM, raloxifene, is used for the prevention and for the treatment of postmenopausal osteoporosis and reducing the risk of invasive breast cancer in postmenopausal women.Areas covered: This article reviews the emerging evidence of the efficacy of raloxifene in postmenopausal women, summarizes the results and places in perspective their therapeutic uses for women having either a high risk of osteoporosis or breast cancer. Emerging clinical evidence suggests bisphosphonates, currently used as drugs for the treatment of osteoporosis, may also reduce breast cancer risk. The status of other SERMs and bisphosphonates are included for completeness. A Medline search of raloxifene, osteoporosis, breast cancer and SERMs was used to derive a database of 355 references.Expert opinion: Readers will understand the value of raloxifene to prevent osteoporosis and breast cancer in postmenopausal women. Although most women do not require pharmacotherapy for menopausal symptoms, many are severely affected by osteoporosis or breast cancer at and beyond menopause and, for such women, pharmacologic intervention is important if they are to retain an acceptable quality of life. It is reasonable to use raloxifene or bisphosphonate as an appropriate drug that targets symptom-free postmenopausal women for treatment and prevention of osteoporosis but raloxifene is proven to reduce the incidence of invasive breast cancer.

Effect of raloxifene on human pancreatic adenocarcinoma growth in vitro and in vivo.

207 Background: The role of estrogen receptor (ER) signaling in pancreatic cancer is unknown. Recently, we demonstated that expression of the isoform ER beta correlates with an adverse prognosis in patients with pancreatic cancer. Here, we show that raloxifene, a specific estrogen receptor modulator (SERM), suppresses in vitro and in vivo tumor growth by interfering with ER beta signaling in human pancreatic adenocarcinoma. Methods: The human pancreatic adenocarcinoma cell line L3.6pl was cultured and exposed to raloxifene in vitro, and cell proliferation was determined by the BrdU assay. To analyze the specificity of raloxifene induced effects, ER knockdown was performed using siRNA specific for ER alpha and ER beta. In an in vivo model of orthotopic tumor xenografts in nude mice, raloxifene was administered daily, and tumor growth was monitored. Expression of ER beta and the proliferation marker Ki-67 were determined by immunohistochemistry. Results: Raloxifene treatment resulted in a potent, dose dependent reduction of proliferation in vitro over a nanomolar dose range. This effect was completely reversed by siRNA knockdown of ER beta, but not ER alpha, indicating an ER isotype specific signaling. In vivo, orthotopic tumor growth, as well as lymph node and liver metastases, was significantly suppressed in raloxifene treated mice. Analogous to the in vitro data, Ki-67 expression in vivo was significantly reduced in raloxifene treated mice, while ER beta expression was not changed in vivo. Conclusions: Inhibition of ER beta signaling by raloxifene results in a potent reduction of human pancreatic adenocarcinoma growth in vitro and in vivo. Treatment with SERMs may be an attractive therapeutic option in subjects expressing the ER beta isotype. No significant financial relationships to disclose.