Estrogen and angiogenesis: A review

Molecular target based combinational therapeutic approaches in thyroid cancer

Background

Thyroid cancer, as with other types of cancer, is dependent on angiogenesis for its continued growth and development. Interestingly, estrogen has been shown to contribute to thyroid cancer aggressiveness in vitro, which is in full support of the observed increased incidence of thyroid cancer in women over men. Provided that estrogen has been observed to contribute to increased angiogenesis of estrogen responsive breast cancer, it is conceivable to speculate that estrogen also contributes to angiogenesis of estrogen responsive thyroid cancer.

Methods

In this study, three human thyroid cancer cells (B-CPAP, CGTH-W-1, ML-1) were treated with estrogen alone or estrogen and anti-estrogens (fulvestrant and 3,3′-diindolylmethane, a natural dietary compound) for 24 hours. The cell culture media was then added to human umbilical vein endothelial cell (HUVECs) and assayed for angiogenesis associated events. Vascular endothelial growth factor (VEGF) levels were also quantified in the conditioned media so as to evaluate if it is a key player involved in these observations.

Results

Conditioned medium from estrogen treated thyroid cancer cells enhanced phenotypical changes (proliferation, migration and tubulogenesis) of endothelial cells typically observed during angiogenesis. These phenotypic changes observed in HUVECs were determined to be modulated by estrogen induced secretion of VEGF by the cancer cells. Lastly, we show that VEGF secretion was inhibited by the anti-estrogens, fulvestrant and 3,3′-diindolylmethane, which resulted in diminished angiogenesis associated events in HUVECs.

Conclusion

Our data establishes estrogen as being a key regulator of VEGF secretion/expression in thyroid cells which enhances the process of angiogenesis in thyroid cancer. These findings also suggest the clinical utility of anti-estrogens as anti-angiogenic compounds to be used as a therapeutic means to treat thyroid cancer. We also observed that 3,3′-diindolylmethane is a promising naturally occurring anti-estrogen which can be used as a part of therapeutic regimen to treat thyroid cancer.

Stromal estrogen receptor-α promotes tumor growth by normalizing an increased angiogenesis

Estrogens directly promote the growth of breast cancers that express the estrogen receptor α (ERα). However, the contribution of stromal expression of ERα in the tumor microenvironment to the protumoral effects of estrogen has never been explored. In this study, we evaluated the molecular and cellular mechanisms by which 17β-estradiol (E2) impacts the microenvironment and modulates tumor development of ERα-negative tumors. Using different mouse models of ER-negative cancer cells grafted subcutaneously into syngeneic ovariectomized immunocompetent mice, we found that E2 potentiates tumor growth, increases intratumoral vessel density, and modifies tumor vasculature into a more regularly organized structure, thereby improving vessel stabilization to prevent tumor hypoxia and necrosis. These E2-induced effects were completely abrogated in ERα-deficient mice, showing a critical role of host ERα. Notably, E2 did not accelerate tumor growth when ERα was deficient in Tie2-positive cells, even in mice grafted with wild-type bone marrow. These results were extended by clinical evidence of ERα-positive stromal cell labeling in the microenvironment of human breast cancers. Together, our findings therefore show that E2 promotes the growth of ERα-negative cancer cells through the activation of stromal ERα (extra-hematopoietic Tie-2 positive cells), which normalizes tumor angiogenesis and allows an adaptation of blood supply to tumors, thereby preventing hypoxia and necrosis. These findings significantly deepen mechanistic insights into the impact of E2 on tumor development with potential consequences for cancer treatment.

Estrogen promotes ER-negative tumor growth and angiogenesis through mobilization of bone marrow-derived monocytes

Estrogen has a central role in the genesis and progression of breast cancers whether they are positive or negative for the estrogen receptor (ER). While therapies that disrupt estrogen biosynthesis or ER activity can treat these diseases in postmenopausal women, in younger women where ovarian function remains intact, these anti-estrogen therapies are not as effective. Moreover, emerging clinical evidence suggests that estrogen may promote other cancers. Thus, circulating estrogens may participate in cancer pathogenesis in ways that are not yet understood. In this study, we show that estrogen can promote the outgrowth of murine xenograft tumors established from patient-derived ER-negative breast cancer cells by influencing the mobilization and recruitment of a proangiogenic population of bone marrow-derived myeloid cells. ERα expression was necessary and sufficient in the bone marrow-derived cells themselves to promote tumor formation in response to estrogen. Our findings reveal a novel way in which estrogen promotes tumor formation, with implications for the development and application of anti-estrogen therapies to treat cancer in premenopausal women.

Coronary artery disease in aging women: a menopause of endothelial progenitor cells?

The cardiovascular protection provided to women during the reproductive age and the unique angiogenic properties of the female reproductive system provide insights into the complex regulatory network of female sex hormones, angiogenic growth factors, and stem cell regulatory molecules. The intricate and interwoven endometrial physiology of the female menstrual cycle shows that in order to harness the physiologic cardioprotection provided by nature to women of reproductive age, for better cardiovascular therapies in postmenopausal women and the population in general, a coherent and systematic approach is needed.

Estrogen activity as a preventive and therapeutic target in thyroid cancer

Thyroid cancer is the most common endocrine-related cancer with increasing incidences during the last five years. Interestingly, according to the American Thyroid Association, the incidences of thyroid proliferative diseases occur four to five times more in women than in men with the risk of developing thyroid disorders being one in every eight females. Several epidemiological studies have suggested a possible correlation between incidences of thyroid malignancies and hormones but the precise contribution of estrogen in thyroid proliferative disease initiation, and progression is not well understood. This review is an attempt to define the phenotypic and genotypic modulatory effects of estrogen on thyroid proliferative diseases. The significance and relevance of expression of estrogen receptors, α and β, in normal and malignant thyroid tissues and their effects on different molecular pathways involved in growth and function of the thyroid gland are discussed. These novel findings open up areas of developing alternative therapeutic treatments and preventive approaches which employ the use of antiestrogen to treat thyroid malignancies.

2-Hydroxyestradiol slows progression of experimental polycystic kidney disease

Male gender is a risk factor for progression of polycystic kidney disease (PKD). 17β-Estradiol (E2) protects experimentally, but clinical use is limited by adverse effects. Novel E2 metabolites provide many benefits of E2 without stimulating the estrogen receptor, and thus may be safer. We hypothesized that E2 metabolites are protective in a model of PKD. Studies were performed in male control Han:SPRD rats, and in cystic males treated with orchiectomy, 2-methoxyestradiol, 2-hydroxyestradiol (2-OHE), or vehicle, from age 3 to 12 wk. Cystic rats exhibited renal functional impairment (∼50% decrease in glomerular filtration and renal plasma flow rates, P < 0.05) and substantial cyst development (20.5 ± 2.0% of cortex area). 2-OHE was the most effective in limiting cysts (6.0 ± 0.7% of cortex area, P < 0.05 vs. vehicle-treated cystic rats) and preserving function, in association with suppression of proliferation, apoptosis, and angiogenesis markers. Downregulation of p21 expression and increased expression of Akt, the mammalian target of rapamycin (mTOR), and some of its downstream effectors were significantly reversed by 2-OHE. Thus, 2-OHE limits disease progression in a cystic rodent model. Mechanisms include reduced renal cell proliferation, apoptosis, and angiogenesis. These effects may be mediated, at least in part, by preservation of p21 and suppression of Akt and mTOR. Estradiol metabolites may represent a novel, safe intervention to slow progression of PKD.

Alcohol and maternal uterine vascular adaptations during pregnancy-part I: effects of chronic in vitro binge-like alcohol on uterine endothelial nitric oxide system and function

BACKGROUND

Pregnancy-induced utero-placental growth, angiogenic remodeling, and enhanced vasodilation are all partly regulated by estradiol-17β-mediated activation of endothelial nitric oxide synthase (eNOS) and nitric oxide (NO) production. However, very little is known about the effects of alcohol on these maternal utero-placental vascular adaptations during pregnancy and its potential role in the pathogenesis of fetal alcohol spectrum disorders (FASDs). In this study, we hypothesized that in vitro chronic binge-like alcohol will decrease uterine arterial endothelial eNOS expression and alter its multisite phosphorylation activity state via disruption of AKT signaling. To study the direct effects of alcohol on uterine vascular adaptations, we further investigated the effects of alcohol on estradiol-17β-induced uterine angiogenesis in vitro.

METHODS

Uterine artery endothelial cells were isolated from pregnant ewes (gestational day 120 to 130; term = 147), fluorescence-activated cell sorted, validated, and maintained in culture to passage 4. To mimic maternal binge drinking patterns, cells were cultured in the absence or presence of a lower (LD) or higher dose (HD) of alcohol in a compensating sealed humidified chamber system equilibrated with aqueous alcohol for 3 hours on 3 consecutive days. Immunoblotting was performed to assess expression of NO system-associated proteins and eNOS multi-site phosphorylation. Following this treatment paradigm, control and binge alcohol-treated cells were passaged, grown for 2 days, and then treated with increasing concentrations of estradiol-17β (0.1, 1, 10, 100 nM) in the absence or presence of LD or HD alcohol to evaluate estradiol-17β-induced angiogenesis index using BrdU proliferation assay.

RESULTS

LD and HD binge-like alcohol decreased uterine arterial eNOS expression (p = 0.009). eNOS multisite phosphorylation activation state was altered: P(635) eNOS was decreased (p = 0.017), P(1177) eNOS was not altered, and P(495) eNOS exhibited an inverse U-shaped dose-dependent relationship with alcohol. LD and HD alcohol decreased the major eNOS-associated protein cav-1 (p < 0.001). However, the commonly implicated AKT pathway did not correlate with eNOS posttranslational modifications. Assessment of uterine vascular adaptation via angiogenesis demonstrated that alcohol abrogated the dose-dependent proliferative effects of estradiol-17β and thus blunted angiogenesis.

CONCLUSIONS

Thus, the maternal uterine vasculature during pregnancy may be vulnerable to chronic binge-like alcohol. Altered eNOS multisite phosphorylation also suggests that alcohol produces specific effects at the level of posttranslational modifications critical for pregnancy-induced uterine vascular adaptations. Finally, the alcohol and estradiol-17β data suggest a negative impact of alcohol on estrogen actions on the uterine vasculature.

Estradiol-mediated tumor neo-vascularization

Neo-vascularization is essential for tumor growth and metastasis and is presumably initiated by bone marrow-derived endothelial progenitor cells (BM-EPCs). These cells predominantly reside in the bone marrow and are recruited at sites of inflammation, tissue damage and tumors. The tissue-specific factors responsible for recruitment of BM-EPCs and neo-vascularization are the subject of intense investigation. Using bone marrow cells from Tek/green fluorescent protein (GFP) transgenic mice, we analyzed the effect of estrogen on the mobilization of BM-EPCs to orthotopically implanted cancer cells in estrogen- and non-estrogen-supplemented ovariectomized mice. The donor marrow cells were unique as they were fluorescently tagged, allowing for the tracking of their migration to the tumor tissues. Results showed that GFP + BM-EPCs were incorporated within the tumor vasculature in comparison to the sham injections. Notably, estrogen supplementation enhanced the mobilization of BM-EPCs to the tumor site. This elevation shows that estrogen may affect tumor neo-vascularization by inducing the mobilization of BM-EPCs. Understanding and characterizing the mechanism involved in the estrogen-induced mobilization of BM-EPCs may serve as a 'Trojan horse' in the delivery of bio-molecules that may disrupt tumor vasculogenesis and induce the targeted killing of tumor cells.

Bevacizumab in metastatic breast cancer: when may it be used?

Tumor angiogenesis, which is necessary for breast cancer growth, invasion and metastases, is regulated by pro-angiogenic factors such as vascular endothelial growth factor (VEGF). Bevacizumab is a recombinant humanized monoclonal antibody that targets VEGF. The addition of bevacizumab to chemotherapy has improved progression-free survival in the first- and second-line treatment of patients with advanced-stage breast cancer. In this article we review the clinical trials testing the utility of bevacizumab for the treatment of metastatic disease.

Sex-based differences in vascular function

Cardiovascular disease is the leading cause of morbidity and mortality for both men and women in the USA. However, there are differences between the sexes in age-dependent onset, severity, symptoms and outcomes. Basic research into the causes of sex-dependent differences in cardiovascular disease is ongoing and includes investigation into genetic variation in expression and distribution of receptors for the sex steroids; specificity of natural and synthetic ligands that activate the sex steroid receptors; and intracellular mechanisms that are activated by the receptors in all components of the vessel wall and blood elements, which integrate to regulate vascular tone, vascular repair and remodeling in health and disease. In this era of personalized medicine, basic research into mechanisms of sex differences in vascular function will result in improved prevention, detection and treatment of cardiovascular disease in both men and women.

Effects of estrogens and endocrine-disrupting chemicals on cell differentiation-survival-proliferation in brain: contributions of neuronal cell lines

Estrogens and estrogen receptors (ER) are key actors in the control of differentiation and survival and act on extrareproductive tissues such as brain. Thus, estrogens may display neuritogenic effects during development and neuroprotective effects in the pathophysiological context of brain ischemia and neurodegenerative pathologies like Alzheimer's disease or Parkinson's disease. Some of these effects require classical transcriptional "genomic" mechanisms through ER, whereas other effects appear to rely clearly on "membrane-initiated mechanisms" through cytoplasmic signal transduction pathways. Disturbances of these mechanisms by endocrine-disrupting chemicals (EDC) may exert adverse effects on brain. Some EDC may act via ER-independent mechanisms but might cross-react with endogenous estrogen. Other EDC may act through ER-dependent mechanisms and display agonistic/antagonistic estrogenic properties. Because of these potential effects of EDC, it is necessary to establish sensitive cell-based assays to determine EDC effects on brain. In the present review, some effects of estrogens and EDC are described with focus on ER-mediated effects in neuronal cells. Particular attention is given to PC12 cells, an interesting model to study the mechanisms underlying ER-mediated differentiating and neuroprotective effects of estrogens.

Timing of the vascular actions of estrogens in experimental and human studies: why protective early, and not when delayed?

Estrogens, and in particular 17β-estradiol (E2), play a pivotal role in sexual development and reproduction and are also implicated in a large number of physiological processes including the cardiovascular system. Although epidemiological studies and Nurses' Health Study suggested, and all animal models of early atheroma clearly demonstrated a vasculoprotective action of both endogenous and exogenous estrogens, the Women's Health Initiative did not confirm the preventive action of estrogens against coronary heart disease (CHD). However, women who initiated hormone therapy closer to menopause tended to have reduced CHD risk compared with increased CHD risk among women more distant from menopause. Thus, it is now mandatory to try to understand the mechanisms that could have influenced the actions of estrogens at various stages of atherosclerosis and/or of life. In this current review, we will summarize our understanding of the potential cellular targets and mechanisms of the vasculoprotective actions of estrogens, as well as of the lack of action of estrogens when administered after a period of hormonal deprivation. The mechanisms of the aggravating role of progestogens such as medroxyprogesterone acetate will be considered. Finally, we will analyze the possibilities to uncouple some beneficial from other undesirable actions following the partial/selective activation of estrogen receptors.

Estrogen administration during superovulation increases oocyte quality and expressions of vascular endothelial growth factor and nitric oxide synthase in the ovary

AIMS

This study investigated whether estrogen administration during superovulation enhances oocyte quality using a mice model. We also investigated whether this estrogen treatment regulates the expressions of angiogenic factors, such as vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS), in the ovary.

METHOD

Female mice were co-injected with various doses of estrogen (1 microM, 10 microM and 100 microM) and pregnant mare serum gonadotrophin during superovulation, followed by human chorionic gonadotrophin injection 48 hours later. Then they were mated with individual males. After 18 hours, zygotes were flushed and cultured to blastocyst. The expression of VEGF and eNOS in the ovary was examined using Western blot and immunohistochemistry. The control group was superovulated without estrogen.

RESULTS

Both numbers of ovulated zygotes and the rate of embryo development to blastocyst were significantly increased in the 1-microM estrogen dose compared to the control group. VEGF and eNOS expressions were stimulated by estrogen treatment. In particular, VEGF expression was significantly increased at 1-microM estrogen concentration, whereas, eNOS expression was significantly increased in all estrogen concentrations compared to controls.

CONCLUSIONS

The study showed that estrogen co-injection during superovulation increased the ovarian response, embryo developmental competence and expressions of VEGF and eNOS in the ovary.

Estrogen plus progestin and breast cancer incidence and mortality in postmenopausal women

CONTEXT

In the Women's Health Initiative randomized, placebo-controlled trial of estrogen plus progestin, after a mean intervention time of 5.6 (SD, 1.3) years (range, 3.7-8.6 years) and a mean follow-up of 7.9 (SD, 1.4) years, breast cancer incidence was increased among women who received combined hormone therapy. Breast cancer mortality among participants in the trial has not been previously reported.

OBJECTIVE

To determine the effects of therapy with estrogen plus progestin on cumulative breast cancer incidence and mortality after a total mean follow-up of 11.0 (SD, 2.7) years, through August 14, 2009.

DESIGN, SETTING, AND PARTICIPANTS

A total of 16,608 postmenopausal women aged 50 to 79 years with no prior hysterectomy from 40 US clinical centers were randomly assigned to receive combined conjugated equine estrogens, 0.625 mg/d, plus medroxyprogesterone acetate, 2.5 mg/d, or placebo pill. After the original trial completion date (March 31, 2005), reconsent was required for continued follow-up for breast cancer incidence and was obtained from 12,788 (83%) of the surviving participants.

MAIN OUTCOME MEASURES

Invasive breast cancer incidence and breast cancer mortality.

RESULTS

In intention-to-treat analyses including all randomized participants and censoring those not consenting to additional follow-up on March 31, 2005, estrogen plus progestin was associated with more invasive breast cancers compared with placebo (385 cases [0.42% per year] vs 293 cases [0.34% per year]; hazard ratio [HR], 1.25; 95% confidence interval [CI], 1.07-1.46; P = .004). Breast cancers in the estrogen-plus-progestin group were similar in histology and grade to breast cancers in the placebo group but were more likely to be node-positive (81 [23.7%] vs 43 [16.2%], respectively; HR, 1.78; 95% CI, 1.23-2.58; P = .03). There were more deaths directly attributed to breast cancer (25 deaths [0.03% per year] vs 12 deaths [0.01% per year]; HR, 1.96; 95% CI, 1.00-4.04; P = .049) as well as more deaths from all causes occurring after a breast cancer diagnosis (51 deaths [0.05% per year] vs 31 deaths [0.03% per year]; HR, 1.57; 95% CI, 1.01-2.48; P = .045) among women who received estrogen plus progestin compared with women in the placebo group.

CONCLUSIONS

Estrogen plus progestin was associated with greater breast cancer incidence, and the cancers are more commonly node-positive. Breast cancer mortality also appears to be increased with combined use of estrogen plus progestin.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00000611.

Calycosin promotes angiogenesis involving estrogen receptor and mitogen-activated protein kinase (MAPK) signaling pathway in zebrafish and HUVEC

Background

Angiogenesis plays an important role in a wide range of physiological processes, and many diseases are associated with the dysregulation of angiogenesis. Radix Astragali is a Chinese medicinal herb commonly used for treating cardiovascular disorders and has been shown to possess angiogenic effect in previous studies but its active constituent and underlying mechanism remain unclear. The present study investigates the angiogenic effects of calycosin, a major isoflavonoid isolated from Radix Astragali, in vitro and in vivo.

Methodology

Tg(fli1:EGFP) and Tg(fli1:nEGFP) transgenic zebrafish embryos were treated with different concentrations of calycosin (10, 30, 100 µM) from 72 hpf to 96 hpf prior morphological observation and angiogenesis phenotypes assessment. Zebrafish embryos were exposed to calycosin (10, 100 µM) from 72 hpf to 78 hpf before gene-expression analysis. The effects of VEGFR tyrosine kinase inhibitor on calycosin-induced angiogenesis were studied using 72 hpf Tg(fli1:EGFP) and Tg(fli1:nEGFP) zebrafish embryos. The pro-angiogenic effects of calycosin were compared with raloxifene and tamoxifen in 72 hpf Tg(fli1:EGFP) zebrafish embryos. The binding affinities of calycosin to estrogen receptors (ERs) were evaluated by cell-free and cell-based estrogen receptor binding assays. Human umbilical vein endothelial cell cultures (HUVEC) were pretreated with different concentrations of calycosin (3, 10, 30, 100 µM) for 48 h then tested for cell viability and tube formation. The role of MAPK signaling in calycosin-induced angiogenesis was evaluated using western blotting.

Conclusion

Calycosin was shown to induce angiogenesis in human umbilical vein endothelial cell cultures (HUVEC) in vitro and zebrafish embryos in vivo via the up-regulation of vascular endothelial growth factor (VEGF), VEGFR1 and VEGFR2 mRNA expression. It was demonstrated that calycosin acted similar to other selective estrogen receptor modulators (SERMs), such as raloxifene and tamoxifen, by displaying selective potency and affinity to estrogen receptors ERα and ERβ. Our results further indicated that calycosin promotes angiogenesis via activation of MAPK with the involvement of ERK1/2 and ER. Together, this study revealed, for the first time, that calycosin acts as a selective estrogen receptor modulator (SERM) to promote angiogenesis, at least in part through VEGF-VEGFR2 and MAPK signaling pathways.

Estradiol stimulates capillary formation by human endothelial progenitor cells: role of estrogen receptor-{alpha}/{beta}, heme oxygenase 1, and tyrosine kinase

Endothelial progenitor cells (EPCs) repair damaged endothelium and promote capillary formation, processes involving receptor tyrosine kinases (RTKs) and heme oxygenase 1 (HO-1). Because estradiol augments vascular repair, we hypothesize that estradiol increases EPC proliferation and capillary formation via RTK activation and induction of HO-1. Physiological concentrations of estradiol (10 nmol/L) increased EPC-induced capillary sprout and lumen formation in matrigel/fibrin/collagen systems. Propyl-pyrazole-triol (PPT; 100 nmol/L; estrogen receptor [ER]-alpha agonist), but not diarylpropionitrile (ER-beta agonist), mimicked the stimulatory effects of estradiol on capillary formation, and methyl-piperidino-pyrazole (ER-alpha antagonist) abolished the effects of estradiol and PPT. Three different RTK activators (vascular endothelial growth factor, hepatocyte growth factor, and stromal derived growth factor 1) mimicked the capillary-stimulating effects of estradiol and PPT. SU5416 (RTK inhibitor) blocked the stimulatory effects of estradiol and PPT on capillary formation. Estradiol increased HO-1 expression by 2- to 3-fold, an effect blocked by SU5416, and PPT mimicked the effects of estradiol on HO-1. The ability of estradiol to enhance capillary formation, increase expression of HO-1, and augment phosphorylation of extracellular signal-regulated kinase 1/2, Akt, and vascular endothelial growth factor receptor 2 was mimicked by its cell-impermeable analog BSA estradiol. Actinomycin (transcription inhibitor) did not alter the effects of estradiol on RTK activity or vascular endothelial growth factor secretion. We conclude that estradiol via ER-alpha promotes EPC-mediated capillary formation by a mechanism that involves nongenomic activation of RTKs and HO-1 activation. Estradiol in particular and ER-alpha agonists in general may promote healing of injured vascular beds by promoting EPC activity leading to more rapid endothelial recovery and capillary formation after injury.

Beta-elemene inhibits melanoma growth and metastasis via suppressing vascular endothelial growth factor-mediated angiogenesis

PURPOSE

It was to assess antiangiogenic effect of β-elemene in vitro and in vivo, and it was involved in inhibiting melanoma growth and metastasis, as well as to elucidate its intrinsic mechanism.

METHODS

Inhibitive effect of β-elemene on B16F10 cells was performed by cell proliferation assay. Angiogenesis assays in vitro including rat aortic ring and chick embryo chorioallantoic membrane were used, as well as melanoma growth and metastasis assay in C57BL/6 mice. Vascular endothelial growth factor (VEGF) expression in vitro and in vivo was measured respectively by western blot analysis and enzyme-linked immunosorbent assay (ELISA). Immunohistochemistry analysis of CD34 and VEGF expression in primary melanoma was also presented.

RESULTS

β-Elemene inhibited B16BF10 cell proliferation starting from 200 μM, but VEGF from 20 μM. Both 20 and 50 μM β-elemene in vitro inhibited VEGF-induced sprouting vessel of rat aortic ring and microvessel formation of chick embryo chorioallantoic membrane. In vivo, tumor size of primary melanoma in mice intraperitoneally treated with β-elemene was significantly smaller than that of the control; CD34 expression of primary melanoma was also suppressed; and the metastatic melanoma colonies and content of melanin in lung were detected obviously decreased in mice of β-elemene-treated groups. Furthermore, results of VEGF expressing in primary melanoma, serum and lung of mice also disclosed that VEGF was inhibited in vivo.

CONCLUSIONS

β-Elemene inhibited melanoma growth and metastasis through suppressing VEGF-mediated angiogenesis. It is a natural potential antiangiogenic agent.

Androgens, angiogenesis and cardiovascular regeneration

PURPOSE OF REVIEW

Striking sex differences exist not only in the incidence of cardiovascular disease, but also in the clinical outcomes. Although cardiovascular events occur earlier in men, in women, it appears they have poorer short-term and long-term outcomes following these events compared to men. Thus, intrinsic sex differences may exist not only in atherogenesis, but also with respect to cardiovascular adaptation/repair in response to ischemia and/or infarction. Angiogenesis, the growth of new blood vessels, is essential for organ development and is critical to cardiovascular repair/regeneration. Although the effect of estrogen on angiogenesis has been studied extensively, the role of androgens has remained largely unexplored.

RECENT FINDINGS

Multiple lines of evidence now suggest an important role for androgens in cardiovascular repair and regeneration. Studies suggest that androgens stimulate angiogenesis via vascular endothelial growth factor-related mechanisms and by the stimulation of erythropoietin production. Furthermore, endothelial progenitor cells, important in angiogenesis, appear to be hormonally regulated and an important target of androgen action.

SUMMARY

Given the age-related decline in androgens, the findings discussed here have implications for therapeutic angiogenesis and androgen replacement therapies in aging and hypogonadal men.

Bevacizumab for advanced breast cancer

Tumor angiogenesis is an important step in breast cancer development, progression, invasion and metastasis. Pro-angiogenic factors such as VEGF regulate angiogenesis and are targets for drug development. Bevacizumab, an anti-VEGF antibody, has demonstrated significant clinical benefit in several solid tumors, including breast cancer. Its use in combination with either paclitaxel or docetaxel has prolonged progression-free survival and increased response rates in the first-line treatment of patients with metastatic breast cancer. This review article discusses the clinical trials establishing the use of bevacizumab for the treatment of advanced breast cancer.

RSK in tumorigenesis: connections to steroid signaling

The Ser/Thr kinase family, RSK, has been implicated in numerous types of hormone-dependent and -independent cancers. However, there has been little consideration of RSKs as downstream mediators of steroid hormone non-genomic effects or of their ability to facilitate steroid receptor-mediated gene expression. Steroid hormone signaling can directly stimulate the MEK/ERK/RSK pathway to regulate cellular proliferation and survival in transformed cells. To date, multiple mechanisms of RSK and steroid hormone receptor-mediated proliferation/survival have been elucidated. For example, RSK enhances proliferation of breast and prostate cancer cells via its ability to control the levels of the estrogen receptor co-activator, cyclin D1. While in lung and other tumors RSK may control apoptosis via estrogen-mediated regulation of mitochondrial integrity. Thus the RSKs could be important anti-cancer therapeutic targets in many different transformed tissues. The recent discovery of RSK-specific inhibitors will advance our current understanding of RSK in transformation and drive these studies into animal and clinical models. In this review we explore the mechanisms associated with RSK in tumorigenesis and their relationship to steroid hormone signaling.

Feasibility trial of letrozole in combination with bevacizumab in patients with metastatic breast cancer

PURPOSE

Preclinical models suggest that the use of anti-vascular endothelial growth factor (anti-VEGF) therapy with antiestrogens may prevent or delay the development of endocrine therapy resistance. We therefore performed a feasibility study to evaluate the safety of letrozole plus bevacizumab in patients with hormone receptor-positive metastatic breast cancer (MBC).

METHODS

Patients with locally advanced breast cancer or MBC were treated with the aromatase inhibitor (AI) letrozole (2.5 mg orally daily) and the anti-VEGF antibody bevacizumab (15 mg/kg intravenously every 3 weeks). The primary end point was safety, defined by grade 4 toxicity using the National Cancer Institute Common Toxicity Criteria, version 3.0. Secondary end points included response rate, clinical benefit rate, and progression-free survival (PFS). Prior nonsteroidal AIs (NSAIs) were permitted in the absence of progressive disease.

RESULTS

Forty-three patients were treated. After a median of 13 cycles (range, 1 to 71 cycles), select treatment-related toxicities included hypertension (58%; grades 2 and 3 in 19% and 26%), proteinuria (67%; grades 2 and 3 in 14% and 19%), headache (51%; grades 2 and 3 in 16% and 7%), fatigue (74%; grades 2 and 3 in 19% and 2%), and joint pain (63%; grades 2 and 3 in 19% and 0%). Eighty-four percent of patients had at least stable disease on an NSAI, confounding efficacy results. Partial responses were seen in 9% of patients and stable disease >or= 24 weeks was noted in 67%. Median PFS was 17.1 months.

CONCLUSION

Combination letrozole and bevacizumab was feasible with expected bevacizumab-related events of hypertension, headache, and proteinuria. Phase III proof-of-efficacy trials of endocrine therapy plus bevacizumab are in progress (Cancer and Leukemia Group B 40503).

A sex-specific role for androgens in angiogenesis

Mounting evidence suggests that in men, serum levels of testosterone are negatively correlated to cardiovascular and all-cause mortality. We studied the role of androgens in angiogenesis, a process critical in cardiovascular repair/regeneration, in males and females. Androgen exposure augmented key angiogenic events in vitro. Strikingly, this occurred in male but not female endothelial cells (ECs). Androgen receptor (AR) antagonism or gene knockdown abrogated these effects in male ECs. Overexpression of AR in female ECs conferred androgen sensitivity with respect to angiogenesis. In vivo, castration dramatically reduced neovascularization of Matrigel plugs. Androgen treatment fully reversed this effect in male mice but had no effect in female mice. Furthermore, orchidectomy impaired blood-flow recovery from hindlimb ischemia, a finding rescued by androgen treatment. Our findings suggest that endogenous androgens modulate angiogenesis in a sex-dependent manner, with implications for the role of androgen replacement in men.

Expressions of vascular endothelial growth factor and nitric oxide synthase III in the thyroid gland of ovariectomized rats are upregulated by estrogen and selective estrogen receptor modulators

BACKGROUND

Estrogen promotes the growth of thyroid cells. Therefore, we analyzed the influence of estrogen and selective estrogen receptor modulators (SERMs) on the expression of vascular endothelial growth factor (VEGF) and nitric oxide synthase III (NOS III) in the thyroid gland of ovariectomized (Ovx) rats.

METHODS

Wistar rats were divided into five groups, and bilateral ovariectomies were performed, except on the Sham-operated controls (Sham). Rats were grouped as follows: Sham; Ovx; and Ovx rats treated with daily subcutaneous injections of estradiol benzoate 3.5 microg/kg, tamoxifen 2.5 mg/kg, or raloxifene 2.5 mg/kg for 50 consecutive days. Control animals received vehicle (propyleneglycol), and at the end of the treatment, rats were sacrificed. The thyroid glands were excised, weighed, and processed for analysis of the expression of VEGF or NOS III by immunohistochemistry. The mean vascular areas were evaluated by immunodetection of alpha-smooth muscle actin.

RESULTS

Thyroid weight and mean vascular area were lower in Ovx as compared with Sham, Ovx + estradiol benzoate, Ovx + Tam, or Ovx + Ral (p < 0.01). VEGF (p < 0.01) and NOS III expressions (p < 0.05) were significantly lower in the Ovx group, as compared with Sham, Ovx + estradiol benzoate, Ovx + Tam, and Ovx + Ral. Immunoreactivity for both VEGF and NOS III was mainly detected in the cytoplasm of the follicular epithelial cells.

CONCLUSIONS

Our data suggest that estrogen and SERMs regulate the thyroid gland vascularization and that tamoxifen and raloxifene behave like estrogen does. Estrogen and SERMs upregulate VEGF and NOS III in such a way as to reverse the effects detected on the thyroid microvasculature of the Ovx rats.

Investigating expression profiles of VEGF-Flk, and Angpt1 during development of gas glands in Japanese eel (Anguilla japonica)

Angiogenesis is a highly regulated physiological process in animals. Angiopoietin-1 (Angpt1) induces the signaling pathways related to vessel maturation in late phase of angiogenesis, which recruits pericyte supplements to make compact interaction with vessel tubes. There are only few data showing Angpt1 functions in fish. By using degenerate primers, partial sequence (812 bp) of Angpt1 was cloned from Anguilla japonica, and deduced amino acids showed 80% similarity to those of zebrafish. Physiological functions of cloned eel Angpt1 were studied by in vitro and in vivo manipulations with gas glands (rete mirabile) taken as the tested target tissues. RT-PCR and immunofluorescent staining techniques were performed to examine the expression patterns of Angpt1 as well as VEGF-Flk. Experimental data showed that, in vitro, bFGF, PPAR beta agonist, and estradiol affected Angpt1 expression; while cobalt ions, a VEGF expression-inducer, did not affect Angpt1 expression. In vivo, expression levels of Angpt1 increased with body growth. Furthermore, Angpt1 expressions increased significantly in the late stage of gas glands in the stimulated eel. Successive expression patterns on VEGF-Flk, and Angpt1 on different development stages of gas glands were observed. Our results suggest that the original function of angiopoietin-1 on angiogenesis is conserved during evolution.

Oestrogen plus progestin and lung cancer in postmenopausal women (Women's Health Initiative trial): a post-hoc analysis of a randomised controlled trial

BACKGROUND

In the post-intervention period of the Women's Health Initiative (WHI) trial, women assigned to treatment with oestrogen plus progestin had a higher risk of cancer than did those assigned to placebo. Results also suggested that the combined hormone therapy might increase mortality from lung cancer. To assess whether such an association exists, we undertook a post-hoc analysis of lung cancers diagnosed in the trial over the entire follow-up period.

METHODS

The WHI study was a randomised, double-blind, placebo-controlled trial undertaken in 40 centres in the USA. 16 608 postmenopausal women aged 50-79 years with an intact uterus were randomly assigned by a computerised, stratified, permuted block algorithm to receive a once-daily tablet of 0.625 mg conjugated equine oestrogen plus 2.5 mg medroxyprogesterone acetate (n=8506) or matching placebo (n=8102). We assessed incidence and mortality rates for all lung cancer, small-cell lung cancer, and non-small-cell lung cancer by use of data from treatment and post-intervention follow-up periods. Analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00000611.

FINDINGS

After a mean of 5.6 years (SD 1.3) of treatment and 2.4 years (0.4) of additional follow-up, 109 women in the combined hormone therapy group had been diagnosed with lung cancer compared with 85 in the placebo group (incidence per year 0.16%vs 0.13%; hazard ratio [HR] 1.23, 95% CI 0.92-1.63, p=0.16). 96 women assigned to combined therapy had non-small-cell lung cancer compared with 72 assigned to placebo (0.14%vs 0.11%; HR 1.28, 0.94-1.73, p=0.12). More women died from lung cancer in the combined hormone therapy group than in the placebo group (73 vs 40 deaths; 0.11%vs 0.06%; HR 1.71, 1.16-2.52, p=0.01), mainly as a result of a higher number of deaths from non-small-cell lung cancer in the combined therapy group (62 vs 31 deaths; 0.09%vs 0.05%; HR 1.87, 1.22-2.88, p=0.004). Incidence and mortality rates of small-cell lung cancer were similar between groups.

INTERPRETATION

Although treatment with oestrogen plus progestin in postmenopausal women did not increase incidence of lung cancer, it increased the number of deaths from lung cancer, in particular deaths from non-small-cell lung cancer. These findings should be incorporated into risk-benefit discussions with women considering combined hormone therapy, especially those with a high risk of lung cancer.

FUNDING

National Heart, Lung and Blood Institute, National Institutes of Health.

Fibrocollagen-covered prosthesis for a noncircumferential segmental tracheal replacement

OBJECTIVE

Fibrocollagen-covered polyester meshes can be used as possible substitutions for tracheal segments if they become integrated into the tissue without complications. The aim of this study was to assess a fibrocollagen-covered polyester prosthesis to be used as a substitution for a tracheal segment.

METHODS

We performed a blind, randomized experimental assay. Adult Wistar rats were assigned to one of 2 groups. Prostheses were made by implanting polyester tubing in a group of animals to cover them with homologous collagen. They were implanted as substitutions of tracheal segments in the experimental group after creating a defect in the anterior wall of the trachea. Clinical, histomorphologic, and immunohistochemical assessments were made at 4 different time points.

RESULTS

The experimental group presented some respiratory distress signs during the first 7 to 10 days, such as stertors, hissing, and low motor activity. After this initial period, the symptoms subsided progressively and disappeared at the end of the first month. These respiratory symptoms caused no mortality. Initially undifferentiated monolayer cells predominated on the implant's surface, but during the last 2 months, the proportion of epithelial and ciliated cells was similar to that seen in control animals. Types I, III, and V collagen fibers were identified around the mesh. The intraluminal area of the tracheas with prostheses and prosthesis thickness were larger during the 4 months of the experiment. The increase in thickness was due to angiogenesis without evidence of fibrosis or chronic inflammation.

CONCLUSIONS

Polyester-collagen prostheses used as substitutions of tracheal segments in rats enabled the proliferation of normal respiratory epithelium and maintained tracheal function without collapse, inflammatory reaction, or secondary stenosis.

Estradiol-induced, endothelial progenitor cell-mediated neovascularization in male mice with hind-limb ischemia

We investigated whether administration of estradiol to male mice augments mobilization of bone marrow-derived endothelial progenitor cells (EPC) and incorporation into foci of neovascularization after hind-limb ischemia, thereby contributing to blood flow restoration. Mice were randomized and implanted with placebo pellets or pellets containing low-dose estradiol (0.39 mg) or high-dose estradiol (1.7 mg). Hind-limb ischemia was induced by unilateral resection of the left femoral artery 1 week after pellet implantation, then EPC mobilization and functional recovery was evaluated. EPC recruitment was assessed in mice transplanted with bone marrow from transgenic donors expressing beta-galactosidase driven by the Tie-2 promoter. EPC culture assay performed 2 weeks after pellet implantation revealed a significantly greater (p<0.05) number of circulating EPCs in the high-dose estradiol group than in the low-dose estradiol and placebo groups. At 3 and 4 weeks after induction of hind-limb ischemia, perfusion was significantly greater (p<0.05) in high-dose estradiol mice than in mice implanted with the low-dose estradiol or placebo pellets. At 1 and 4 weeks after hind-limb ischemia surgery, more bone marrow-derived EPCs, identified as beta-galactosidase-positive cells, were observed in ischemic regions from high-dose estradiol animals than in low-dose (p<0.05) or placebo groups (p<0.05). These results indicate that estradiol dose-dependently increases the levels of EPCs in peripheral blood in male animals, improves the recovery of blood flow, and decreases limb necrosis after hind-limb ischemia, and that this enhancement occurs, in part, through augmentation of EPC mobilization and greater incorporation of bone marrow-derived EPCs into foci of neovascularization.

Interaction of estrogen and tumor necrosis factor alpha in endothelial cell migration and early stage of angiogenesis

The role of estrogen replacement therapy in postmenopausal women remains controversial. The authors hypothesized that contradictory results with estrogen therapy may be explained by estrogen's potent proangiogenic property, which could be protective in women without atherosclerotic disease but in the presence of chronic inflammation, could lead to destabilization of atherosclerotic plaques. The authors thus examined the interaction between 17beta-estradiol (E2) and the inflammatory cytokine tumor necrosis factor alpha (TNFalpha) in an early stage of angiogenesis. Human umbilical endothelial cells were grown to confluence. Migration was assessed with a wound assay and proliferation was assessed with 5-bromo-2'-deoxyuridine (BrDU). Cells were treated with medium alone, TNFalpha at 0.3, 1, or 20 ng/ml, E2 at 20 nM, or the combination of E2 and TNFalpha. The authors used real-time polymerase chain reaction (PCR) to measure changes in expression of the angiogenesis genes angiopoeitin-2 (Ang-2), vacular endothelial growth factor (VEGF)-A and -C, and interleukin (IL)-8. A large dose of TNFalpha (20 ng/ml) inhibited healing at 24 to 48 h and the addition of E2 preserved some healing. E2 by itself doubled migration, with only a minimal effect on proliferation. A low dose of TNFalpha (0.3 ng/ml) had no effect on migration, 1.0 ng/ml moderately increased it, but the addition of E2 to both doses of TNFalpha increased migration. There was no change in migration when cells were pretreated with E2 and given TNFalpha after wounding, whereas pretreatment with TNFalpha followed by E2 significantly increased wound healing. The nitric oxide synthase (NOS) inhibitor N-nitro-l-arginine-methyl ester (l-NAME) completely blocked the E2 effect on migration. TNFalpha (0.3 and 1.0 ng/ml) increased expression of VEGF-C (2.8 +/- 0.1- and 2.5 +/- 0.2-fold, respectively) and IL-8 (32.8 +/- 1.2- and 42.7 +/- 3.6-fold, respectively) mRNA, but E2 had no significant effect on these molecules. E2 increases the angiogenic activity of TNFalpha. This could potentially worsen the stability of complex atherosclerotic plaques and increase cardiovascular events.

Estrogens stimulate the proliferation of human cholangiocarcinoma by inducing the expression and secretion of vascular endothelial growth factor

BACKGROUND

Estrogens may induce the proliferation of neoplastic cells by activating neo-angiogenesis.

AIM

To evaluate the effect of estrogens on the expression of vascular endothelial growth factor (VEGF) and related receptors (VEGF-R) in human cholangiocarcinoma and the role played by VEGF in mediating the proliferative effects of estrogens.

METHODS

Seven biopsies of intra-hepatic cholangiocarcinoma and the HuH-28 cell lines were investigated. Cell proliferation was measured by both PCNA Western blot and MTS proliferation assay.

RESULTS

By immunohistochemistry, biopsies of human cholangiocarcinoma stained positively for VEGF-A and VEGF-C and related receptors. HuH-28 cells expressed VEGF-A, -C, and VEGFR-1, -2, -3 and, their protein level was enhanced by 17beta-estradiol in association with the stimulation of cell proliferation. 17beta-Estradiol-stimulated proliferation of HuH-28 cells was blocked by 70% by VEGF-TRAP, a receptor-based VEGF inhibitor. 17beta-Estradiol induced the secretion of VEGF in the supernatant of HuH-28 cells. The stimulatory effect of 17beta-estradiol on the protein expression of VEGF-A, VEGF-C and VEGFR-1, -2, -3 was blocked by antagonists of ER (Ici182,780) or insulin-like growth factor 1-receptor (alphaIR3).

CONCLUSIONS

With the limitations of experiments performed in a cell line, our study indicates that VEGF plays a major role in mediating the proliferative effects of estrogens on human cholangiocarcinoma.

Metabolic syndrome and collateral vessel formation in patients with documented occluded coronary arteries: association with hyperglycaemia, insulin-resistance, adiponectin and plasminogen activator inhibitor-1

Aims

The metabolic syndrome (MS) is associated with an increased cardiovascular risk. Patients with the MS have endothelial dysfunction, decreased circulating adiponectin, and a high expression of angiogenic inhibitors such as plasminogen activator inhibitor-1 (PAI-1). We hypothesized that such patients, in the event of a coronary occlusion, might exhibit a less developed collateral circulation.

Methods and results

Three hundred and eighty-seven consecutive patients with at least one coronary occlusion of a major coronary vessel at diagnostic angiography were prospectively enrolled. Collateral development was graded with validated angiographic methods. The MS was defined according to the ATP-III definition. Fasting glucose, adiponectin, insulin concentrations, and PAI-1 were measured at the time of angiography. MS was associated with less developed collateral vessels (P = 0.005). In multivariable analysis adjusting for potential confounding factors including the duration of coronary occlusion (P = 0.0001), fasting glycaemia (P = 0.0007), low adiponectin concentration (P = 0.01), insulin-resistance (HOMA-IR; P = 0.01), high circulating PAI-1 concentration (P = 0.01), and hypertension (P = 0.008) were independently associated with poor coronary collateral vessel development.

Conclusion

This study shows that in patients with coronary occlusion, collateral circulation is impaired in patients with the MS. This association is partly related to fasting glycaemia and to key parameters linked to insulin resistance.

Role of estrogen receptors in menstrual cycle-related neoangiogenesis and their influence on endothelial progenitor cell physiology

OBJECTIVE

To study whether estrogen receptors (ERs) are expressed in vitro and in vivo by female circulating endothelial progenitor cells (EPCs); and the role of ERs in the periodic vascular damage and repair that occurs during the menstrual cycle.

DESIGN

Quantification of circulating progenitor cells, EPCs, and relative CXCR4+ fraction by flow cytometry. Quantification of plasma 17beta-E(2) by electrochemiluminescent immunoassay. Expression of ERs by immunofluorescence and immunohistochemistry. Estrogen receptor, CXCR4, and matrix metalloproteinase 9 gene expression by reverse transcriptase-polymerase chain reaction and real-time polymerase chain reaction.

SETTING

University clinic and academic research laboratory.

PATIENT(S)

Twelve young fertile women (aged 22-27 years) observed for 6 months, 10 postmenopausal women (aged 52-63 years), and 50 male control subjects (aged 24-61 years).

INTERVENTION(S)

Blood (35 mL) was collected at each observation point.

MAIN OUTCOME MEASURE(S)

Correlation between 17beta-E(2) exposure and neoangiogenesis markers.

RESULT(S)

Estrogen receptors are expressed both in cultured EPCs after prolonged estrogen stimulation and in circulating EPCs, such as in CD34+ cells in bone marrow. The number of ER-beta+ and CXCR4+ EPCs increased during the ovulatory phase, and this increase is probably mediated by ER-beta and matrix metalloproteinase 9.

CONCLUSION(S)

Estrogens play a key role in neoangiogenesis processes, such as endometrium recovery, and this mechanism involves both a central action (on bone marrow) and a cytokine-mediated peripheral one (on endothelium).

Estrogen-replacement therapy promotes angiogenesis after acute myocardial infarction by enhancing SDF-1 and estrogen receptor expression

Although observational data suggest that estrogen-replacement therapy (ERT) may confer cardioprotection, estrogen's putative protective role has been challenged. This study investigated the effect of estradiol on peripheral blood stem cells and angiogenesis after acute myocardial infarction and potential mechanisms of estrogen's pro-angiogenesis effect. An ovariectomized rat acute myocardial infarction (AMI) model was established by ligation of the left anterior descending coronary followed by delivery of varying doses of estradiol benzoate. Serum estradiol levels were assessed by radioimmunoassay. Expression levels of alpha and beta estrogen receptor (ER) proteins in myocardium were determined by Western blotting. CD34(+) cells in myocardium at 24 h and in peripheral blood 1, 3 and 7 days after AMI were measured by immunohistochemistry and flow cytometry, respectively. Stromal cell-derived factor (SDF-1) expression and capillary density in myocardium were detected by immunohistochemistry. In ovariectomized rats, ERT significantly increased estradiol levels and up-regulated ER-alpha and -beta expression relative to untreated controls. Furthermore, ERT elevated the number of CD34(+) cells in peripheral blood and myocardium, increased SDF-1 expression, and increased capillary density 4 weeks after AMI. Therefore, our data suggest that estrogen can promote the mobilization and homing of bone marrow stem cells into the myocardium and can increase capillary density in myocardium after AMI. The pro-angiogenesis effect of ERT is associated with enhanced SDF-1 and ER-alpha and -beta expression in myocardium after AMI.

Tamoxifen and aromatase inhibitors differentially affect vascular endothelial growth factor and endostatin levels in women with breast cancer

PURPOSE

Circulating and cellular proangiogenic and antiangiogenic proteins such as vascular endothelial growth factor (VEGF) and endostatin contribute to the local angiogenic balance. We explored the effects of tamoxifen and aromatase inhibitors on concentrations of VEGF and endostatin in plasma, serum, and platelet releasate (induced by platelet activation).

EXPERIMENTAL DESIGN

VEGF and endostatin concentrations were measured with a quantitative immunoassay before and after 1 to 5 weeks of treatment in 30 women with breast cancer treated with either tamoxifen (n = 14) or aromatase inhibitors (n = 16). Platelet activation was induced by a thrombin receptor agonist.

RESULTS

Tamoxifen therapy resulted in an increase in platelet releasate concentrations of VEGF (P = 0.01) but no change in plasma VEGF. In contrast, aromatase inhibitor therapy did not affect serum, plasma, or platelet releasate VEGF. In univariate analysis, aspirin use attenuated the tamoxifen-associated increase in VEGF in the platelet releasate and decreased serum levels of VEGF (P = 0.03). Aromatase inhibitor therapy resulted in a decrease in serum endostatin concentrations (P = 0.04), whereas plasma concentrations of endostatin tended to be higher during treatment with aromatase inhibitors (P = 0.06). Tamoxifen therapy resulted in no change in serum or plasma endostatin concentrations. Platelet releasate concentrations of endostatin did not change with either treatment. Interindividual variability was noted among both aromatase inhibitor--and tamoxifen-treated patients.

CONCLUSIONS

Tamoxifen and aromatase inhibitor therapy affect VEGF and endostatin levels and likely contribute to the angiogenic balance in breast cancer patients. Aspirin decreased the proangiogenic effects of tamoxifen, suggesting that antiplatelet and/or antiangiogenic therapy might improve the effectiveness of tamoxifen in women with breast cancer.

Oestrogen promotes coronary angiogenesis even under normoxic conditions

Angiogenic therapy is one of the new treatments of ischaemic heart disease. Oestrogen has angiogenic properties under hypoxic condition, and if oestrogen also induces angiogenesis under normoxic condition, it could be used in combination with other angiogenic therapies in the treatment of ischaemic heart disease. In this study, we evaluated the angiogenic effect of high-dose oestrogen treatment in normoxic rat heart tissue. Fifty-two ovariectomized rats were randomized in oestrogen-treated and control groups. 17beta-oestradiol (1 mg/week) and normal saline (1 mg/week) were administered intramuscularly in the treatment and control groups for 2 months. After that, coronary capillary density and coronary vessel permeability were measured. The serum vascular endothelial growth factor (VEGF) level was also measured before and after the treatment. The results indicate that coronary capillary density (number of capillary per square millimetre) and coronary vessel permeability (fluorescence intensity) were significantly higher in the oestrogen-treated group than in the control group (628 +/- 26 per mm(2) versus 540 +/- 26 per mm(2); P < 0.05 and 207 +/- 10 versus 147 +/- 19 per gram tissue; P < 0.05). Oestrogen treatment increased serum VEGF level in the oestrogen-treated group compared to the control group (52 +/- 3 versus 33 +/- 6 pg/ml; P < 0.05), but interestingly VEGF was also increased in the control group after placebo treatment. It seems that high-dose oestrogen administration has angiogenic properties even in normoxic conditions. These angiogenic properties may result from oestrogen's direct effect on VEGF or other mechanisms, such as endothelial progenitor cell mobilization. Because of the broad effect of oestrogen on angiogenic growth factors and endothelial cells, more studies are required to clarify angiogenic properties of high-dose oestrogen.

Estradiol-estrogen receptor: a key interplay of the expression of syndecan-2 and metalloproteinase-9 in breast cancer cells

Estrogens are related with the growth and development of target tissues and play a critical role in breast cancer progression. The effects of estrogens are mediated by the estrogen receptors ERalpha and ERbeta, which are members of the nuclear steroid receptor superfamily. To date, it is not known how these hormones elicit many of their effects on extracellular matrix molecules and how these effects can be connected with ER expression. For this purpose, the effect of estradiol on ER expression as well as on proteoglycan and metalloproteinase expression was studied. The effect of E2 on extracellular matrix molecule expression has been studied using ERalpha suppression in breast cancer cells. Our studies using ERalpha-positive MCF-7 cells show that estradiol affects the expression of syndecan-2, but not of syndecan-4, through ERalpha. Furthermore, the ability of estradiol to affect MMP-9 and TIMP-1 expression is connected with ERalpha status. Together, these data demonstrate the significant role of ERalpha on mediating the effect of estradiol on extracellular matrix molecules.

Current NCI-sponsored Cooperative Group trials of endocrine therapies in breast cancer

Over several decades, investigators working through National Cancer Institute-sponsored Cooperative Groups have contributed to major advances in the endocrine treatment of breast cancer. Accomplishments include the benefit of tamoxifen therapy for early stage invasive and noninvasive breast cancer, the benefit of raloxifene and tamoxifen for prevention of breast cancer, the improved efficacy of tamoxifen after chemotherapy as opposed to concurrent administration, and the ability of letrozole administered after 5 years of tamoxifen to improve disease-free survival. Most recently, Cooperative Group studies have contributed to the development of a molecular profiling test, Oncotype Dx, which identifies women who have an excellent prognosis with hormonal therapy alone. Ongoing phase 3 clinical trials address the following questions: Is prolonged duration of aromatase inhibitor (AI) therapy beneficial? What is the efficacy and toxicity of steroidal versus nonsteroidal AIs in adjuvant treatment? Is combination hormonal therapy with an estrogen receptor down-regulator (fulvestrant) and an AI superior to an AI alone in the treatment of metastatic breast cancer? Does ovarian suppression offer superior benefit to standard therapy in the treatment of premenopausal breast cancer? What is the role of chemotherapy for early stage breast cancer selected via molecular profiling analysis? How can targeted therapies be used effectively in combination? Studies in subsets of patients defined by molecular profiling will be necessary to fully define breast cancer subtypes and realize the promise of personalized medicine. Close research partnerships that promote large-scale translational research are essential to the continuation of rapid achievements in this field.

Palmar erythema

Palmar erythema (PE), an often overlooked physical finding, is due to several physiologic or systemic pathologic states. PE can exist as a primary physiologic finding or as a secondary marker of systemic pathology. Primary or physiologic PE can be due to heredity, occurs in at least 30% of pregnant women as a result of associated alterations in the function of the skin and its microvasculature, or may be a diagnosis of exclusion (i.e. idiopathic PE). Secondary PE from systemic pathology encompasses a wide range of disease states. Twenty-three percent of patients with liver cirrhosis, from varying causes, can manifest PE as a result of abnormal serum estradiol levels. Patients with a rare neonatal liver disease such as Wilson disease and hereditary hemochromatosis may exhibit PE along with the other systemic manifestations of the genodermatoses. PE has been reported to occur in >60% of patients with rheumatoid arthritis and is associated with a favorable prognosis. Up to 18% of patients with thyrotoxicosis and 4.1% of patients with diabetes mellitus can have PE. This cutaneous manifestation of diabetes occurs more often than the more classic diseases such as necrobiosis lipoidica diabeticorum (0.6%). PE can be seen in early gestational syphilis and among patients with human T-lymphotrophic virus-1-associated myelopathy. Drug-induced PE with hepatic damage has been documented with use of amiodarone, gemfibrozil, and cholestyramine, while topiramate and albuterol (salbutamol) have been reported to cause PE in the setting of normal liver function. Fifteen percent of patients with both metastatic and primary brain neoplasms may have PE. Increased levels of angiogenic factors and estrogens from solid tumors have been postulated as the cause of PE in such cases. Erythema ab igne can mimic PE, and patients with atopic diathesis are more likely to have PE than matched control subjects. Smoking and chronic mercury poisoning are environmental causes of PE.No treatment of primary PE is indicated. If medication is the cause of PE, the drug responsible should be discontinued if possible. Identification of PE related to underlying disorders should be followed by treatment of the underlying condition. In light of the numerous etiologies of PE, this article reviews the current literature and provides a framework to help guide the clinician in determining the cause of PE in patients presenting with this finding.

Epulis gravidarum manum: pyogenic granuloma of the hand occurring in pregnant women

Pyogenic granuloma, also known as lobular capillary hemangioma, is a benign vascular tumor of the skin and mucous membranes. Whereas the literature describes pyogenic granulomas of pregnancy as occurring mainly within the gingival or oral mucosa, we present 5 cases of a histologically confirmed pyogenic granuloma on the hands of gravid women, each with no history of antecedent trauma. These tumors failed to resolve spontaneously postpartum necessitating surgical removal. We propose the term epulis gravidarum manum to describe this skin lesion.

Tumor dormancy and surgery-driven interruption of dormancy in breast cancer: learning from failures

Primary tumor removal, usually considered intrinsically beneficial, can perturb metastatic homeostasis, and for some patients results in the acceleration of metastatic cancer. The continuous-growth model is required to yield to an interrupted-growth model, the implications of which are episodes of tumor dormancy. This Review analyzes the recent evolution of two paradigms related to the development of breast cancer metastases. The evolution of the paradigms described herein is supported by a growing body of findings from experimental models, and is required to explain breast cancer recurrence dynamics for patients undergoing surgery with or without adjuvant chemotherapy.

Tamoxifen induces heparanase expression in estrogen receptor-positive breast cancer

PURPOSE

Mammalian heparanase degrades heparan sulfate, the main polysaccharide of the basement membrane. Heparanase is an important determinant in cancer progression, acting via the breakdown of extracellular barriers for invasion, as well as release of heparan sulfate-bound angiogenic and growth-promoting factors. The present study was undertaken to elucidate molecular mechanisms responsible for heparanase overexpression in breast cancer.

EXPERIMENTAL DESIGN

To characterize heparanase regulation by estrogen and tamoxifen and its clinical relevance for breast tumorigenesis, we applied immunohistochemical analysis of tissue microarray combined with chromatin immunoprecipitation assay, reverse transcription-PCR, and Western blot analysis.

RESULTS

A highly significant correlation (P<0.0001) between estrogen receptor (ER) positivity and heparanase overexpression was found in breast cancer. Binding of ER to heparanase promoter accompanied estrogen-induced increase in heparanase expression by breast carcinoma cells. Surprisingly, heparanase transcription was also stimulated by tamoxifen, conferring a proliferation advantage to breast carcinoma cells grown on a naturally produced extracellular matrix. Heparanase overexpression was invariably detected in ER-positive second primary breast tumors, developed in patients receiving tamoxifen for the initial breast carcinoma. The molecular mechanism of the estrogenlike effect of tamoxifen on heparanase expression involves recruitment of transcription coactivator AIB1 to the heparanase promoter.

CONCLUSIONS

Heparanase induction by ligand-bound ER represents an important pathway in breast tumorigenesis and may be responsible, at least in part, for the failure of tamoxifen therapy in some patients. Our study provides new insights on breast cancer progression and endocrine therapy resistance, offering future strategies for delaying or reversing this process.

The complex role of estrogens in inflammation

There is still an unresolved paradox with respect to the immunomodulating role of estrogens. On one side, we recognize inhibition of bone resorption and suppression of inflammation in several animal models of chronic inflammatory diseases. On the other hand, we realize the immunosupportive role of estrogens in trauma/sepsis and the proinflammatory effects in some chronic autoimmune diseases in humans. This review examines possible causes for this paradox. This review delineates how the effects of estrogens are dependent on criteria such as: 1) the immune stimulus (foreign antigens or autoantigens) and subsequent antigen-specific immune responses (e.g., T cell inhibited by estrogens vs. activation of B cell); 2) the cell types involved during different phases of the disease; 3) the target organ with its specific microenvironment; 4) timing of 17beta-estradiol administration in relation to the disease course (and the reproductive status of a woman); 5) the concentration of estrogens; 6) the variability in expression of estrogen receptor alpha and beta depending on the microenvironment and the cell type; and 7) intracellular metabolism of estrogens leading to important biologically active metabolites with quite different anti- and proinflammatory function. Also mentioned are systemic supersystems such as the hypothalamic-pituitary-adrenal axis, the sensory nervous system, and the sympathetic nervous system and how they are influenced by estrogens. This review reinforces the concept that estrogens have antiinflammatory but also proinflammatory roles depending on above-mentioned criteria. It also explains that a uniform concept as to the action of estrogens cannot be found for all inflammatory diseases due to the enormous variable responses of immune and repair systems.

Can surgery provoke the outgrowth of latent breast cancer? A unifying hypothesis

AbstractTo explain bimodal relapse patterns, we have previously suggested that metastatic breast cancer growth commonly includes periods of temporary dormancy at both the single cell and avascular micrometastasis phases (with 1 year and 2 year half-lives respectively). We further suggested that primary surgery sometimes initiates growth of distant dormant disease accelerating relapse. These iatrogenic events are common in that they occur in over half of all relapses. Surgery induced angiogenesis is mostly confined to premenopausal node positive patients in which case 20% of patients are so affected. We review here how this hypothesis explains a vairety of previously unrelated breast cancer phenomenon including 1) the mammography paradox for women age 40–49 untreated with adjuvant therapy, 2) the particularly high benefit of adjuvant chemotherapy for premenopausal node positive patients, 3) the heterogeneity of breast cancer, 4) the aggressiveness of cancer in young women, 5) the outcome differences with timing of surgery within the menstrual cycle, 6) the common myths regarding cancer spreading “when the air hits it” and treatment “provoking” the tumor, 7) the excess mortality of blacks over whites, and 8) reports from physicians 2000 years ago. In parallel to physicists who have long sought to explain all of physics with a unified field theory, we now suggest temporary dormancy together with surgery induced tumor growth provides a unifying theory for much of breat cancer.

New Perspectives on Mars and Venus: Unravelling the Role of Androgens in Gender Differences in Cardiovascular Biology and Disease

There are substantial gender differences in the pattern, severity and clinical outcomes of coronary heart disease independent of environmental risk factor exposure. As a consequence, there has been considerable interest in the potential role of sex hormones in atherogenesis, particularly the potential protective effects of oestrogen. However, the failure of the recent clinical randomised trials to show a cardioprotective effect for oestrogen coupled with a growing interest in androgen replacement therapy in elderly men has refocused interest on the role of androgens in cardiovascular biology and disease. Over the last decade, compelling evidence has emerged that sex differences in vascular biology are not only determined by gender-related differences in sex steroid levels but also by gender-specific tissue and cellular characteristics which mediate sex-specific responses to a variety of stimuli. In the vasculature, androgens often act in a gender-specific manner, with differential effects in male and female cells. This gender-dependent regulation may have important implications for understanding the basis of the gender gap in atherosclerosis and may eventually lead to the development of sex-specific treatments for cardiovascular disease. This review will summarise the current data for the role of androgens in gender differences in coronary heart disease and cardiovascular biology.

The effect of maturation and age on oestrogen-induced functional hypertrophy of the female rabbit bladder

OBJECTIVE

To evaluate the effect of maturation and ageing on oestrogen-induced functional hypertrophy of the female rabbit bladder.

MATERIALS AND METHODS

Twenty female rabbits were separated into two groups of 10 each by age, young (immature) and old rabbits and each age group was subdivided into three subgroups. The rabbits in subgroup 1 were controls, subgroup 2 were ovariectomized (Ovx) and subgroup 3 were Ovx and received 17-beta oestradiol (1 mg/kg/day) by a subcutaneous slow-release tablet implant. After 15 days of treatment, the rabbits were killed, the bladder was excised, and the body and base separated; two full-thickness longitudinal strips from the ventral surface of the bladder body, and one full-thickness strip from the base, were prepared for contractile studies. The contractile responses to electrical-field stimulation, carbachol, ATP and KCl were determined for both the bladder body and base strips. In addition, full-thickness strips of bladder body and base were fixed in formalin for histological and immunohistological studies.

RESULTS

Ovx plus oestradiol resulted in significant increases in bladder weight and responses to all forms of stimulation in young and old rabbits (except for the response to KCl). Vascular density and the smooth muscle (SM)/collagen ratio significantly increased after oestradiol replacement. Interestingly, the increase in vascular density was greater in the young than in the old rabbits.

CONCLUSIONS

The present study shows that oestrogen supplementation mediates a functional hypertrophy characterized by increased contractile responses to all forms of stimulation in both young and old rabbits. The increased contractile responses might be explained by the increases in vascular density and SM/collagen ratio.