Estrogen promotes angiogenic activity in human umbilical vein endothelial cells in vitro and in a murine model

Core-shell cell bodies composed of human cbMSCs and HUVECs for functional vasculogenesis

Rapid induction and creation of functional vascular networks is essential for the success of treating ischemic tissues. The formation of mature and functional vascular networks requires the cooperation of endothelial cells (ECs) and perivascular cells. In the study, we used a thermo-responsive hydrogel system to fabricate core-shell cell bodies composed of cord-blood mesenchymal stem cells (cbMSCs) and human umbilical vascular ECs (HUVECs) for functional vasculogenesis. When seeded on Matrigel, the shelled HUVECs attempted to interact and communicate vigorously with the cored cbMSCs initially. Subsequently, HUVECs migrated out and formed tubular structures; cbMSCs were observed to coalesce around the HUVEC-derived tubes. With time progressing, the tubular networks continued to expand without regression, indicating that cbMSCs might function as perivascular cells to stabilize the nascent networks. In the in vivo study, cbMSC/HUVEC bodies were embedded in Matrigel and implanted subcutaneously in nude mice. At day 7, visible blood-filled vessels were clearly identified within the implant containing cbMSC/HUVEC bodies, indicating that the formed vessels anastomosed with the host vasculature. The cored cbMSCs were stained positive for smooth muscle actin, suggesting that they underwent smooth muscle differentiation and formed microvessels with the shelled HUVECs, as the role of perivascular cells. These data confirm that the formation of mature vessels requires heterotypic cooperation of HUVECs and MSCs. This study provides a new strategy for therapeutic vasculogenesis, by showing the feasibility of using cbMSC/HUVEC bodies to create functional vascular networks.

The G-protein-coupled estrogen receptor GPER in health and disease

Estrogens mediate profound effects throughout the body and regulate physiological and pathological processes in both women and men. The low prevalence of many diseases in premenopausal women is attributed to the presence of 17β-estradiol, the predominant and most potent endogenous estrogen. In addition to endogenous estrogens, several man-made and plant-derived molecules, such as bisphenol A and genistein, also exhibit estrogenic activity. Traditionally, the actions of 17β-estradiol are ascribed to two nuclear estrogen receptors (ERs), ERα and ERβ, which function as ligand-activated transcription factors. However, 17β-estradiol also mediates rapid signaling events via pathways that involve transmembrane ERs, such as G-protein-coupled ER 1 (GPER; formerly known as GPR30). In the past 10 years, GPER has been implicated in both rapid signaling and transcriptional regulation. With the discovery of GPER-selective ligands that can selectively modulate GPER function in vitro and in preclinical studies and with the use of Gper knockout mice, many more potential roles for GPER are being elucidated. This Review highlights the physiological roles of GPER in the reproductive, nervous, endocrine, immune and cardiovascular systems, as well as its pathological roles in a diverse array of disorders including cancer, for which GPER is emerging as a novel therapeutic target and prognostic indicator.

Estradiol induces endothelial cell migration and proliferation through estrogen receptor-enhanced RhoA/ROCK pathway

Migration and proliferation of endothelial cells are involved in re-endothelialization and angiogenesis, two important cardiovascular processes that are increased in response to estrogens. RhoA, a small GTPase which controls multiple cellular processes, is involved in the control of cell migration and proliferation. Our aim was to study the role of RhoA on estradiol-induced migration and proliferation and its dependence on estrogen receptors activity. Human umbilical vein endothelial cells were stimulated with estradiol, in the presence or absence of ICI 182780 (estrogen receptors antagonist) and Y-27632 (Rho kinase inhibitor). Estradiol increased Rho GEF-1 gene expression and RhoA (gene and protein expression and activity) in an estrogen receptor-dependent manner. Cell migration, stress fiber formation and cell proliferation were increased in response to estradiol and were also dependent on the estrogen receptors and RhoA activation. Estradiol decreased p27 levels, and significantly raised the expression of cyclins and CDK. These effects were counteracted by the use of either ICI 182780 or Y-27632. In conclusion, estradiol enhances the RhoA/ROCK pathway and increases cell cycle-related protein expression by acting through estrogen receptors. This results in an enhanced migration and proliferation of endothelial cells.

The role of estrogen deficiency in skin ageing and wound healing

The links between hormonal signalling and lifespan have been well documented in a range of model organisms. For example, in C. elegans or D. melanogaster, lifespan can be modulated by ablating germline cells, or manipulating reproductive history or pregnenolone signalling. In mammalian systems, however, hormonal contribution to longevity is less well understood. With increasing age human steroid hormone profiles change substantially, particularly following menopause in women. This article reviews recent links between steroid sex hormones and ageing, with special emphasis on the skin and wound repair. Estrogen, which substantially decreases with advancing age in both males and females, protects against multiple aspects of cellular ageing in rodent models, including oxidative damage, telomere shortening and cellular senescence. Estrogen's effects are particularly pronounced in the skin where cutaneous changes post-menopause are well documented, and can be partially reversed by classical Hormone Replacement Therapy (HRT). Our research shows that while chronological ageing has clear effects on skin wound healing, falling estrogen levels are the principle mediator of these effects. Thus, both HRT and topical estrogen replacement substantially accelerate healing in elderly humans, but are associated with unwanted deleterious effects, particularly cancer promotion. In fact, much current research effort is being invested in exploring the therapeutic potential of estrogen signalling manipulation to reverse age-associated pathology in peripheral tissues. In the case of the skin the differential targeting of estrogen receptors to promote healing in aged subjects is a real therapeutic possibility.

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.

Androgen stimulates endothelial cell proliferation via an androgen receptor/VEGF/cyclin A-mediated mechanism

Growing evidences support that androgen displays beneficial effects on cardiovascular functions although the mechanism of androgen actions remains to be elucidated. Modulation of endothelial cell growth and function is a potential mechanism of androgen actions. We demonstrated in the present study that androgens [dihydrotestosterone (DHT) and testosterone], but not 17β-estradiol, produced a time- and dose-dependent induction of cell proliferation in primary human aortic endothelial cells (HAECs) as evident by increases in viable cell number and DNA biosynthesis. Real-time qRT-PCR analysis showed that DHT induced androgen receptor (AR), cyclin A, cyclin D1, and vascular endothelial growth factor (VEGF) gene expression in a dose- and time-dependent manner. The addition of casodex, a specific AR antagonist, or transfection of a specific AR siRNA blocked DHT-induced cell proliferation and target gene expression, indicating that the DHT effects are mediated via AR. Moreover, coadministration of SU5416 to block VEGF receptors, or transfection of a specific VEGF-A siRNA to knockdown VEGF expression, produced a dose-dependent blockade of DHT induction of cell proliferation and cyclin A gene expression. Interestingly, roscovitine, a selective cyclin-dependent kinase inhibitor, also blocked the DHT stimulation of cell proliferation with a selective inhibition of DHT-induced VEGF-A expression. These results indicate that androgens acting on AR stimulate cell proliferation through upregulation of VEGF-A, cyclin A, and cyclin D1 in HAECs, which may be beneficial to cardiovascular functions since endothelial cell proliferation could assist the repair of endothelial injury/damage in cardiovascular system.

Glucocorticoid-mediated inhibition of angiogenic changes in human endothelial cells is not caused by reductions in cell proliferation or migration

Background

Glucocorticoid-mediated inhibition of angiogenesis is important in physiology, pathophysiology and therapy. However, the mechanisms through which glucocorticoids inhibit growth of new blood vessels have not been established. This study addresses the hypothesis that physiological levels of glucocorticoids inhibit angiogenesis by directly preventing tube formation by endothelial cells.

Methodology/Principal Findings

Cultured human umbilical vein (HUVEC) and aortic (HAoEC) endothelial cells were used to determine the influence of glucocorticoids on tube-like structure (TLS) formation, and on cellular proliferation (5-bromo-2′-deoxyuridine (BrdU) incorporation), viability (ATP production) and migration (Boyden chambers). Dexamethasone or cortisol (at physiological concentrations) inhibited both basal and prostaglandin F_2α (PGF_2α)-induced and vascular endothelial growth factor (VEGF) stimulated TLS formation in endothelial cells (ECs) cultured on Matrigel, effects which were blocked with the glucocorticoid receptor antagonist RU38486. Glucocorticoids had no effect on EC viability, migration or proliferation. Time-lapse imaging showed that cortisol blocked VEGF-stimulated cytoskeletal reorganisation and initialisation of tube formation. Real time PCR suggested that increased expression of thrombospodin-1 contributed to glucocorticoid-mediated inhibition of TLS formation.

Conclusions/Significance

We conclude that glucocorticoids interact directly with glucocorticoid receptors on vascular ECs to inhibit TLS formation. This action, which was conserved in ECs from two distinct vascular territories, was due to alterations in cell morphology rather than inhibition of EC viability, migration or proliferation and may be mediated in part by induction of thrombospodin-1. These findings provide important insights into the anti-angiogenic action of endogenous glucocorticoids in health and disease.

Lower extremity changes experienced during pregnancy

The anatomic and physiologic changes occurring with pregnancy result in a variety of symptoms affecting the lower extremity. The purpose of this investigation is to provide a comprehensive look at the lower extremity changes experienced during pregnancy and correlate symptoms with underlying etiology in a literature review. In this retrospective study, 100 postpartum women were interviewed regarding the lower extremity changes experienced in pregnancy. The interview included dermatologic, vascular, neurologic, and musculoskeletal portions. Results demonstrate more than 50% of women reported faster toenail growth, roughened toenail texture, increased dryness of the skin, swelling of the foot, ankle, and leg, unsteady gait, increased foot width, and hip pain. Though a majority of patients did not experience the remaining symptoms represented in the interview, all results are pertinent and deserve understanding to provide better insight and care for the pregnant woman. Therefore, a thorough literature review is presented to correlate the outcomes of the present study with previously published research.

Detection of RXFP1 receptors in skin biopsies from children with congenital adrenal hyperplasia: a preliminary report

OBJECTIVE

Relaxin may potentiate the effect of topical estrogen treatment to eradicate post-incisional scarring in congenital adrenal hyperplasia (CAH) patients undergoing genitoplasty. The aim of this study was to determine whether CAH skin is capable of responding to relaxin.

PATIENTS AND METHODS

Skin biopsies were obtained from four female CAH patients (aged 2-9 years; Prader 4-5, salt-wasting, 21-hydroxylase deficiency, Caucasian) during routine genitoplasty surgery and screened for relaxin receptors. All received corticosteroid and mineralocorticoid replacement therapy. Specimens were sectioned, mounted and screened for the presence of the putative H2 relaxin receptor using conventional two-antibody immunohistochemistry. Tissue controls were processed concurrently.

RESULTS

Tissue controls evidenced appropriate staining. Biopsies from CAH patients stained positively for RXFP1 expression while some variation between specimens was evident. Staining occurred adjacent to the basement membrane of the epithelium, localized to germinative basal keratinocytes.

CONCLUSION

Based on a limited patient sample, germinative keratinocytes in CAH patients appear competent to respond to relaxin perhaps topically applied. Given that relaxin downregulates collagen accretion and upregulates collagenases, its use may potentiate the effects of estradiol and abrogate post-incisional wound scarring. More research is needed to confirm or refute this thesis.

Promotion of direct angiogenesis in vitro and in vivo by Puerariae flos extract via activation of MEK/ERK-, PI3K/Akt/eNOS-, and Src/FAK-dependent pathways

Puerariae flos has been used for oriental herbal medicine; however, its angiogenic effect has not been elucidated. We found that the extract from Puerariae flos (PFE) increased in vitro angiogenic events, such as endothelial cell proliferation, migration, and tube formation, as well as in vivo neovascularization. These events were followed by the activation of multiple signal modulators, such as extracellular signal-regulated kinase (ERK), Akt, endothelial nitric oxide synthase (eNOS), nitric oxide production, p38, Src, and focal adhesion kinase (FAK), without increasing vascular endothelial growth factor (VEGF) expression. Inhibition of ERK, Akt, and eNOS suppressed PFE-induced angiogenic events, and inhibition of p38 and Src activities blocked PFE-induced endothelial cell migration. PFE did not affect the expression of intracellular adhesion molecule-1 and vascular cell adhesion molecule-1 and transendothelial permeability, which are involved in the adverse effects of the well-known angiogenic inducer VEGF. These results suggest that PFE directly stimulates angiogenesis through the activation of MEK/ERK-, phosphatidylinositol 3-kinase/Akt/eNOS-, and Src/FAK-dependent pathways, without altering VEGF expression, vascular inflammation, and permeability in vitro and in vivo and may be used as a therapeutic agent for ischemic disease and tissue regeneration.

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.

Proliferation, behavior, and cytokine gene expression of human umbilical vascular endothelial cells in response to different titanium surfaces

Success of dental implantation is initially affected by wound healing of both, hard and soft tissues. Endothelial cells (ECs) are involved as crucial cells in the angiogenesis and inflammation process of wound healing. In the present study, proliferation, mobility, cluster formation, and gene expression of angiogenesis-related molecules of human umbilical vascular endothelial cells (HUVECs) were investigated on titanium surfaces with different roughnesses: acid-etched (A), coarse-grit-blasted and acid-etched (SLA) surfaces, as well as on hydrophilic modified modA and modSLA surfaces. Cell behaviors were analyzed by proliferation assay and time-lapse microscopy, gene expression was analyzed by real time PCR. Results showed that cell proliferation, mobility, and cluster formation were highest on modA surfaces compared with all other surfaces. HUVECs moved slowly and exhibited seldom cell aggregation on SLA and modSLA surfaces during the whole observing period of 120 h. The gene expressions of the angiogenesis-related factors von Willebrand factor, thrombomodulin, endothelial cell protein C receptor, and adhesion molecules intercellular adhesion molecule-1 and E-selectin were most enhanced on modSLA surfaces. These results suggest that modA surface is optimal for proliferation and angiogenic behavior of ECs. However, modSLA surface seems to promote ECs to express angiogenesis-related factor genes, which play essential roles in controlling inflammation and revascularization of wound healing.

Effect and mechanism of panaxoside Rg1 on neovascularization in myocardial infarction rats

OBJECTIVE

To investigate the effects and mechanisms of panaxoside Rg1 on the new vessel formation in acute myocardial infarction (AMI) rats.

METHODS

The AMI model of male Sprague-Dawley (SD) rats was established, and rats were randomly divided into the AMI model group, the treatment group of panaxoside Rg1, the placebo group and the treatment group of panaxoside Rg1 plus rapamycin. Cardiac creatases were determined with 1 mL blood drawn from vena caudalis of the rats 48 h after the model was successfully made. After 4 weeks, Evans blue was injected into the aorta roots of the rats, and then, red tetrazoline was dyed again and the myocardial infarction area was evaluated. The microvessel density (MVD) of infarction area was determined by the immunohistochemistry of CD31; enzyme-linked immunosorbent assay (ELISA) was used to detect the protein content of CD31 and hypoxia inducible factor-1alpha (HIF-1alpha) of the infarction area.

RESULTS

The MVD in the infarction area and the contents of CD31 and HIF-1alpha in the Rg1 treatment group were higher than those in the AMI model group significantly (P<0.05). The cardiac creatase and infarction area were lower in the Rg1 treatment group than those in the AMI model group significantly (P<0.05). The above effects, however, disappeared when rapamycin, the antagonist of mammalian target of rapamycin (mTOR), was administered simultaneously.

CONCLUSIONS

Panaxoside Rg1 could increase the expression of HIF-1alpha and CD31 of myocardium and stimulate the angiogenesis. The above mentioned role of panaxoside Rg1 might be related to the excitation of mTOR receptor.

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.

In vitro angiogenesis: endothelial cell tube formation on gelled basement membrane extract

A protocol is presented here for a rapid, quantitative and reliable in vitro angiogenesis assay that can be adapted for high throughput use. Endothelial cells are plated on a gelled basement matrix, their natural substrate, and form capillary-like structures with a lumen. The assay can be used to identify inhibitors or stimulators of angiogenesis, as well as genes and signaling pathways involved in angiogenesis. It has also been used to identify endothelial progenitor cells. This assay involves endothelial cell adhesion, migration, protease activity and tubule formation. This tube formation assay is preferred, as other in vitro assays for angiogenesis, such as cell adhesion, migration and invasion, measure limited steps in the angiogenesis process. The tube formation assay on basement membrane can be completed in a day because transformed endothelial cells form tubes within 3 h, whereas non-transformed endothelial cells form tubes within 6 h.

Estradiol-17beta and its cytochrome P450- and catechol-O-methyltransferase-derived metabolites stimulate proliferation in uterine artery endothelial cells: role of estrogen receptor-alpha versus estrogen receptor-beta

Estradiol-17beta (E(2)beta) and its metabolites, which are sequentially synthesized by cytochrome P450s and catechol-O-methyltransferase to form 2 and 4-hydroxyestradiol (OHE(2)) and 2- and 4-methoxestradiol (ME(2)), are elevated during pregnancy. We investigated whether cytochrome P450s and catechol-O-methyltransferase are expressed in uterine artery endothelial cells (UAECs) and whether E(2)beta and its metabolites modulate cell proliferation via ER-alpha and/or ER-beta and play roles in physiological uterine angiogenesis during pregnancy. Cultured ovine UAECs from pregnant and nonpregnant ewes were treated with 0.1 to 100.0 nmol/L of E(2)beta, 2-OHE(2), 4-OHE(2), 2-ME(2), and 4-ME(2). ER-alpha or ER-beta specificity was tested using ICI 182 780, ER-alpha-specific 1,3-bis(4-hydroxyphenyl)-4-methyl-5-[4-(2-piperidinyleth oxy)phenol]-1H-pyrazole dihydrochloride, ER-beta-specific 4-[2-phenyl-5,7-bis(trifluoromethyl)pyrazolo [1,5-a]pyrim idin-3-yl]phenol antagonists and their respective agonists ER-alpha-specific 4,4',4"-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol and ER-beta-specific 2,3-bis(4-Hydroxyphenyl)-propionitrile. Angiogenesis was evaluated using 5-bromodeoxyuridine proliferation assay. Using confocal microscopy and Western analyses to determine enzyme location and levels, we observed CYP1A1, CYP1A2, CYP1B1, CYP3A4, and catechol-O-methyltransferase expression in UAECs; however, expressions were similar between nonpregnant UAECs and pregnant UAECs. E(2)beta, 2-OHE(2), 4-OHE(2), and 4-ME(2) treatments concentration-dependently stimulated proliferation in pregnant UAECs but not in nonpregnant UAECs; 2-ME(2) did not stimulate proliferation in either cell type. Proliferative responses of pregnant UAECs to E(2)beta were solely mediated by ER-beta, whereas responses to E(2)beta metabolites were neither ER-alpha nor ER-beta mediated. We demonstrate an important vascular role for E(2)beta, its cytochrome P450- and catechol-O-methyltransferase-derived metabolites, and ER-beta in uterine angiogenesis regulation during pregnancy that may be dysfunctional in preeclampsia and other cardiovascular disorders.

A poly(propylene fumarate)--calcium phosphate based angiogenic injectable bone cement for femoral head osteonecrosis

Osteonecrosis of the femoral head commonly occurs when the blood supply to bone was disrupted. The general treatment for early stages of necrosis in the femoral head is core decompression. However, the long-term outcome of this operation is usually compromised due to collapse of the necrotic bone. In this study, poly(propylene fumarate) (PPF) and calcium phosphate cement (CPC) were combined to provide appropriate mechanical strength after core-decompressed femoral heads and offer the properties of osteoconductivity. Effects of different ratios of CPC to PPF on mechanical and cytotoxicity were investigated. Results show that bone cement is less cytotoxic with the C/P ratio raise, and the increment of the CPC proportion also strengthens the mechanical strength, reduces the crosslinking temperature and diminishes excessive swelling of the cement. With addition of ginsenoside Rg1 the bone cement composite can also offer angiogenic effect. The drug release profiles were analyzed and the angiogenecity of released Rg1 was confirmed by the assay of tube formation in human umbilical vein endothelial cells (HUVECs). In summary, the newly developed angiogenic bone cement composite possesses remarkable development potential for application to treating osteonecrosis of the femoral head.

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.

Myocyte enhancer factor 2 and class II histone deacetylases control a gender-specific pathway of cardioprotection mediated by the estrogen receptor

RATIONALE

Gender differences in cardiovascular disease have long been recognized and attributed to beneficial cardiovascular actions of estrogen. Class II histone deacetylases (HDACs) act as key modulators of heart disease by repressing the activity of the myocyte enhancer factor (MEF)2 transcription factor, which promotes pathological cardiac remodeling in response to stress. Although it is proposed that HDACs additionally influence nuclear receptor signaling, the effect of class II HDACs on gender differences in cardiovascular disease remains unstudied.

OBJECTIVE

We aimed to examine the effect of class II HDACs on post-myocardial infarction remodeling in male and female mice.

METHODS AND RESULTS

Here we show that the absence of HDAC5 or -9 in female mice protects against maladaptive remodeling following myocardial infarction, during which there is an upregulation of estrogen-responsive genes in the heart. This genetic reprogramming coincides with a pronounced increase in expression of the estrogen receptor (ER)alpha gene, which we show to be a direct MEF2 target gene. ERalpha also directly interacts with class II HDACs. Cardioprotection resulting from the absence of HDAC5 or -9 in female mice can be attributed, at least in part, to enhanced neoangiogenesis in the infarcted region via upregulation of the ER target gene vascular endothelial growth factor-a.

CONCLUSIONS

Our results reveal a novel gender-specific pathway of cardioprotection mediated by ERalpha and its regulation by MEF2 and class II HDACs.

Estrogen receptor modulators and estrogen receptor beta immunolabelling in human umbilical vein endothelial cells

Human umbilical vein endothelial cells (HUVEC) exposed to the female sex hormone estradiol show different kinds of effects including increased elasticity, activation of plasma membrane Na+/H+ exchange, prostacyclin production, prevention of apoptosis and many others. The aim of this study was the systematic analysis of the immunolabelling of estrogen receptors (ERs), ERalpha and ERbeta, in HUVEC after stimulation with different commercially available ER modulators and ER agonists or antagonists. HUVEC response to these substances was shown to be regulated via ERbeta. ERalpha immunolabelling or up-regulation was abrogated after application of estrogen derivatives, selective estrogen receptor modulators (SERM) and ER agonists or antagonists. Immunolabelling of ERbeta was significantly increased by estradiol, estrone, ethinylestradiol and tumour necrosis factor alpha (TNFalpha). SERM, such as Tamoxifen, and pure antagonists, such as ICI 182.780, stimulated ERbeta in HUVEC at low concentrations, whereas higher concentrations inhibited ERbeta immunolabelling. The pure estrogen receptor agonist 2,3-bis (4-hydroxyphenyl) proprionitrile (DPN) exhibited its activating potential at low concentrations. In contrast, higher concentrations resulted in a down-regulation of ERbeta. Estrogenic effects in HUVEC, independent of stimulation or inhibition, are mediated via the ERbeta. SERM such as Tamoxifen and ER antagonists such as ICI 182.780 act as ER activators in low concentrations, whereas higher concentrations lead to inhibitory effects.

Women and heart disease--physiologic regulation of gene delivery and expression: bioreducible polymers and ischemia-inducible gene therapies for the treatment of ischemic heart disease

Ischemic heart disease (IHD) is the leading cause of death in the United States today. This year over 750,000 women will have a new or recurrent myocardial infarction. Currently, the mainstay of therapy for IHD is revascularization. Increasing evidence, however, suggests that revascularization alone is insufficient for the longer-term management of many patients with IHD. To address these issues, innovative therapies that extend beyond revascularization to protection of the myocyte and preservation of ventricular function are required. The emergence of gene therapy and proteomics offers the potential for innovative prophylactic and treatment strategies for IHD. The goal of our research is to develop therapeutic gene constructs for the treatment of myocardial ischemia that are clinically safe and effective. Toward this end, we describe the development of physiologic regulation of gene delivery and expression using bioreducible polymers and ischemia-inducible gene therapies for the potential treatment of ischemic heart disease in women.

Estrogen receptor beta in breast cancer--diagnostic and therapeutic implications

More than 10 years have passed since the discovery of the second estrogen receptor, estrogen receptor beta (ERbeta). It is now evident that ERalpha is not the only ER in breast cancer cells; in fact, ERbeta is expressed in the majority of breast cancers although at lower levels than in the normal breast. In addition, ERbeta is expressed in breast cancer infiltrating lymphocytes, fibroblasts and endothelial cells, all known to influence tumor growth. By overexpressing or knocking-out ERbeta in breast cancer cell lines, several researchers have investigated its function with respect to proliferation and tumor growth. It appears that ERbeta is anti-proliferative, in many ways antagonising the function of ERalpha. Furthermore, phytoestrogens have a binding-preference for ERbeta and several epidemiological studies indicate a breast cancer preventing effect of this class of compounds. Tamoxifen is one of the standard, adjuvant treatments for ERalpha positive breast cancer, classically thought to mediate its effect through ERalpha. However, in several recent studies, ERbeta has been described as a potential marker for tamoxifen response. In summary, experimental, epidemiological as well as diagnostic studies point towards ERbeta as an important factor in breast cancer, opening up the possibility for novel ERbeta-selective therapies in the treatment of breast cancer.

Effect of estrogen on the blood supply of pituitary autografts in rats

Estrogens are known to cause pituitary enlargement and lactotroph proliferation. They also modulate pituitary angiogenesis and induce tumor formation. Pituitary grafts, due to the loss of hypothalamic dopamine, also show lactotroph hyperplasia. We investigated the role of estrogen on rat pituitary autograft vascularization by light and transmission electron microscopy, and assessed prolactin (PRL) blood levels, microvessel density (MVD) and cell proliferation using the BrdU labeling index. All adenohypophysial cell types were identified by immunohistochemistry (streptavidin-biotin-peroxidase complex method). The proangiogenic factors, vascular endothelial growth factor (VEGF), its receptor Flk-1, and hypoxia inducible factor-1alpha (HIF-1alpha) were similarly demonstrated. The prevalence of lactotrophs, as well as more intense staining for VEGF, Flk-1 and HIF-1alpha, was noted in those grafts exposed to estrogen, mainly in the area surrounding the central necrotic core. Immunostaining showed Flk-1 expression increased in endothelial cells of the estrogen-exposed grafts as compared with those unexposed. In contrast to the grafts not exposed to estrogen, in the estrogen-exposed grafts, only fenestrated endothelium could be demonstrated, suggesting that estrogen induces fenestration of newly formed capillaries. There was an increase in blood PRL levels in the estrogen-treated groups as compared with controls. Both MVD and BrdU labeling indices were higher in grafts exposed to estrogen, especially after 4 weeks. Our results suggest that estrogen administration not only enhances the expression of proangiogenic factors in the pituitary grafts but also induces their expression at earlier stages, leading to rapid neoformation of purely fenestrated capillaries.

Unique and synergistic roles for 17beta-estradiol and macrophage migration inhibitory factor during cutaneous wound closure are cell type specific

The cutaneous wound healing response is complex, comprising numerous overlapping events including inflammation, fibroblast migration, reepithelialization, and wound contraction. With increased age and resultant reduced systemic estrogens, these processes are disrupted and delayed healing ensues. We have demonstrated previously that the proinflammatory cytokine macrophage migration inhibitory factor (MIF) acts as a global regulator of wound healing mediating the majority of estrogen's healing promoting activity. MIF is expressed by numerous wound cell types yet the interaction between estrogens and MIF at the cellular level is still poorly understood. In this study we demonstrate novel accelerated healing in MIF null mice using an excisional wound model. Moreover, we show cell-type-specific differences in the effects of 17beta-estradiol and/or MIF on the cellular function of a range of wound cell types in vitro. Intriguingly, 17beta-estradiol is able to promote the migration of all cell types studied indicating a clear role for cell migration in accelerated wound healing.

An easy to assemble microfluidic perfusion device with a magnetic clamp

We have built and characterized a magnetic clamp for reversible sealing of PDMS microfluidic chips against cover glasses with cell cultures and a microfluidic chip for experiments on shear stress response of endothelial cells. The magnetic clamp exerts a reproducible uniform pressure on the microfluidic chip, achieving fast and reliable sealing for liquid pressures up to 40 kPa inside the chip with <10% deformations of microchannels and minimal variations of the substrate shear stress in perfusion flow. The microfluidic chip has 8 test regions with the substrate shear stress varying by a factor of 2 between each region, thus covering a 128-fold range from low venous to arterial. The perfusion is driven by differential pressure, which makes it possible to create pulsatile flows mimicking pulsing in the vasculature. The setup is tested by 15-40 hours perfusions over endothelial monolayers with shear stress in the range of 0.07-9 dyn/cm(2). Excellent cell viability at all shear stresses and alignment of cells along the flow at high shear stresses are repeatedly observed. A scratch wound healing assay under a shear flow is demonstrated and cell migration velocities are measured. Transfection of cells with a fluorescent protein is performed, and migrating fluorescent cells are imaged at a high resolution under shear flow in real time. The magnetic clamp can be closed with minimal mechanical perturbation to cells on the substrate and used with a variety of microfluidic chips for experiments with adherent and non-adherent cells.

Menstruation angina: a case report

Introduction

Menstruation is commonly associated with migraine and irritable bowel but is rarely correlated with angina or myocardial ischaemia. Only a small number of cases have been reported suggesting a link between menstruation and myocardial ischaemic events.

Case presentation

A case of menstruation angina is reported in order to raise awareness of this association. A 47-year-old South Asian woman presented with recurrent chest pains in a monthly fashion coinciding with her menstruations. Each presentation was associated with troponin elevation. Angioplasty failed to resolve her symptoms but she eventually responded to hormonal therapy.

Conclusions

The possibility of menstruation angina should always be taken into account in any female patients from puberty to menopause presenting with recurrent chest pains. This can allow an earlier introduction of hormonal therapy to arrest further myocardial damage.

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.

Biologic therapy of breast cancer: focus on co-inhibition of endocrine and angiogenesis pathways

There remains a high unmet need for effective treatments for metastatic breast cancer. In recent years there have been many advances in the understanding of biological basis of cancer. Several cellular pathways have been identified that play crucial roles in causing or maintaining the cancer phenotype. Many new agents that target these pathways have entered the clinic or are being investigated. In order to improve the therapeutic efficacy seen with single-agent regimens, rational combinations of targeted agents are being evaluated in ongoing trials. The optimal sequencing and combination of agents has yet to be established. Endocrine and vascular endothelial growth factor pathways are the two most prominent pathways active in breast cancer cells and inhibition of either of these is associated with clinical benefit. Here we discuss the rationale for simultaneously targeting these pathways and highlight ongoing clinical trials.

Disparate effects of simvastatin on angiogenesis during hypoxia and inflammation

AIMS

Studies have shown that some of statin's pleiotropic effects were achieved by either promotion or inhibition of angiogenesis, depending on the underlying disease. This study tested the hypothesis that the angiogenic potential of simvastatin is related to the microenvironmental conditions.

MAIN METHODS

Human umbilical vein endothelial cells (HUVEC) were studied after exposure to hypoxia or the inflammatory factors tumor necrosis factor (TNF)-alpha, with or without co-incubation with simvastatin (1 micromol/L) and mevalonate. HUVEC angiogenesis was evaluated by tube formation, migration, and proliferation assays. Hypoxia inducible factor (HIF)-1alpha, vascular endothelial growth factor (VEGF), Akt, endothelium nitric oxide synthase (e-NOS), and oxidative stress were evaluated.

KEY FINDINGS

HUVEC angiogenesis increased during hypoxia (tube length 14.7+/-0.5 vs. 7.8+/-0.6 mm, p<0.05) and further enhanced by simvastatin (19.3+/-1.1 mm, p<0.05 vs. hypoxia alone), which downregulated the expression of the HIF-1 inhibitor PHD2 and upregulated HIF-1alpha, VEGF, and Akt, without changing oxidative stress or eNOS. Incubation with TNF-alpha promoted HUVEC angiogenesis (7.4+/-0.2 vs. 6.5+/-0.2 mm, p<0.05) with increased oxidative stress. However, simvastatin inhibited this promotion (2.5+/-0.3 mm, p<0.001 vs. TNF-alpha alone) by decreasing oxidative stress, VEGF, Akt, and eNOS.

SIGNIFICANCE

We conclude that at the same dosage, simvastatin can either promote or inhibit angiogenesis, possibly by activating upstream regulators of HIF-1alpha in hypoxia, but conversely interfering with angiogenic signaling downstream to inflammation. These opposing angiogenic effects should be considered in the therapeutic strategies with statins.

17beta-estradiol regulates the secretion of TGF-beta by cultured human dermal fibroblasts

Estrogen plays an important role in skin homeostasis, as demonstrated by the changes seen in the skin of post-menopausal women, changes reversed by HRT. Estrogen also has a role in wound healing, since estrogen deficiency as occurs post-menopausally and in ovariectomised animals, is associated with a reduced rate of wound healing. Estrogen appears to modulate all phases of wound healing with effects on inflammatory cells, epithelialization, angiogenesis, extracellular matrix deposition and tissue remodelling. This study was designed to investigate the effects of 17beta-estradiol on cultured human dermal fibroblasts using an in vitro wound-healing assay. The end points investigated were cell migration, proliferation, total collagen secretion and active TGF-beta1 secretion. 17beta-estradiol significantly increased the migration and proliferation of cultured dermal fibroblasts following mechanical wounding, although the secretion of total soluble collagen was not altered. An increase in TGF-beta1 was demonstrated by unwounded confluent dermal fibroblast monolayers in response to 17beta-estradiol, but paradoxically, a decrease in the secretion of TGF-beta1 was demonstrated in the mechanically wounded dermal fibroblasts. These results identify human dermal fibroblasts as estrogen target cells and provide further evidence for a role by which estrogen regulates this particular cell type as part of the wound-healing process. However, the paradoxical nature of the effect of estrogen on TGF-beta1 secretion following mechanical wounding suggests that the cellular mechanism of action is complex. A greater understanding of the cell-specific action of estrogen may help to develop therapies that will improve cutaneous wound healing in the future.

Rapid recruitment of temporally distinct vascular gene sets by estrogen

Cardiovascular disease is the leading cause of mortality for both men and women in developed countries. The sex steroid hormone estrogen is required for normal vascular physiology. Estrogen functions by binding to intracellular estrogen receptors (ER), ERalpha and ERbeta, ligand-activated transcription factors that are expressed in both vascular endothelial and smooth muscle cells. We recently demonstrated that long-term (8 d) estrogen treatment in vivo in mice recruits distinct vascular gene sets mediated by ERalpha and ERbeta and that the promoters from these gene sets are enriched for binding sites of specific transcription factors, leading to the hypothesis that estrogen initiates a cascade of early transcriptional events that modulate gene expression in the vasculature. Here we test this hypothesis using gene expression profiling to examine initial transcriptional events (2-8 h) mediated by estrogen in blood vessels. Our data reveal that 1) estrogen regulates temporally distinct cascades of vascular gene expression, 2) initially, estrogen-mediated vascular gene repression predominates, 3) the earliest estrogen-recruited gene program is enriched in vascular transcription factors that can interact with binding sites present in estrogen-regulated vascular genes recruited subsequently, and 4) estrogen-regulated genes recruited next have specific functions, including lipid metabolism and cellular growth and proliferation that are potentially important for estrogen's known vascular functions. In summary, estrogen directly and rapidly recruits specific transcriptional factors that then propagate distinct cascades of gene expression. These data define the temporal recruitment of specific vascular genes by estrogen and enable further analysis of the mechanisms by which estrogen directly regulates vascular function.

Differing transcriptional responses to pulsed or continuous estradiol exposure in human umbilical vein endothelial cells

This study used human umbilical vein endothelial cells (HUVECs) that were treated with 17beta-estradiol for 5 days as 1h pulse or 24h continuous treatment at concentrations such that the 24h exposure (concentration x time) was identical in both conditions. Cell proliferation was studied and gene expression profiling was carried out using the Affymetrix GeneChip microarray analysis. Changes in morphology and apoptosis in HUVECs were examined with electron microscopy. Time-course studies of expression of genes vascular endothelial growth factor (VEGF), inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) were performed by quantitative PCR. We observed that cell proliferation was significantly decreased over days 3-5 with pulsed estradiol treatment relative to constant exposure. Microarray results showed that after 5 days, 801 genes differed (P<0.05) between continuous versus pulsed estradiol treatment. Functional analysis showed a significant number of genes to be associated with apoptosis and cell cycle pathways. We did not find any evidence of apoptosis from flow cytometry or electron microscopy examination. Our study highlights a large number of significantly different molecular responses to estradiol depending upon the mode of administration of estradiol. Significant changes were observed in genes involved in apoptosis and proliferation including VEGF, IGF receptors, and tumor protein p53.

Estradiol accelerates endothelial healing through the retrograde commitment of uninjured endothelium

Although the accelerative effect of 17beta-estradiol (E2) on endothelial regrowth has been clearly demonstrated, the local cellular events accounting for this beneficial vascular action are still uncertain. In the present work, we compared the kinetics of endothelial healing of mouse carotid arteries after endovascular and perivascular injury. Both basal reendothelialization as well as the accelerative effect of E2 were similar in the two models. Three days after endothelial denudation, a regenerative area was observed in both models, characterized by similar changes in gene expression after injury, visualized by en face confocal microscopy (EFCM). A precise definition of the injury limits was only possible with the perivascular model, since it causes a complete and lasting decellularization of the media. Using this model, we demonstrated that the migration of uninjured endothelial cells precedes proliferation (bromodeoxyuridine incorporation) and that these events occur at earlier time points with E2 treatment. We have also identified an uninjured retrograde zone as an intimate component of the endothelial regeneration process. Thus, in the perivascular model, the regenerative area can be subdivided into a retrograde zone and a reendothelialized area. Importantly, both areas are significantly enlarged by E2. In conclusion, the combination of the electric perivascular injury model and EFCM is well adapted to the visualization of the endothelial monolayer and to investigate cellular events involved in reendothelialization. This process is accelerated by E2 as a consequence of the retrograde commitment of an uninjured endothelial zone to migrate and proliferate, contributing to an enlargement of the regenerative area.

Possibilities and potential roles of estrogen in the pathogenesis of proliferation hemangiomas formation

Hemangiomas, often categorized as angiogenic diseases, are the most common tumors of infancy, the life span of which is generally divided into proliferating phase, involuting phase, and involuted phase. Despite their high prevalence, the mechanism leading to proliferation hemangiomas formation is poorly understood and the best approach to their management remains controversial. None of the current therapeutic modalities is ideal, partly because the pathogenesis of hemangioma and the mechanism of its proliferation are far from clear. Many clues reveal that estrogen has an important role in developing the vascular system, experimental and clinical evidences accumulated in recent years also suggest the potential for estrogen to influence neovascularization. Based on those, we hypothesize that estrogen play a potential role in the development of hemangiomas, mainly by regulating some key angiogenic factors, including MMP-9, EPCs, VEGF, NO, etc. Accepting the hypothesis to be correct, a therapy that identify estrogen as a potential target for the design of new, more specific treatments can be used to prevent the proliferation hemangiomas formation. The hypothesis may lead a new direction in the study of mechanisms for proliferation hemangiomas formation, and further study of the precise mechanisms for estrogen-induced hemangiomas will produce effective antiestrogens and estrogen receptor antagonists as new medication for the very difficult problem.

Hormone receptor expression in renal angiomyolipoma: clinicopathologic correlation

OBJECTIVES

Although renal angiomyolipoma (AML) occurs more commonly in females than males, the origin of this difference in incidence by sex is unknown. Therefore, we investigated the expression of the androgen receptor (AR), estrogen receptor subtypes alpha (ERalpha) and beta (ERbeta), progesterone receptor, and the enzyme aromatase in renal AML.

METHODS

We evaluated specimens from 110 patients who had undergone resection of a renal AML, including 90 women and 20 men. Immunohistochemistry was performed using monoclonal antibodies on paraffin-embedded tissue sections. Expression was correlated with patient demographics and tumor pathologic features.

RESULTS

ERbeta was expressed in 100% (106 of 106) of the AML specimens evaluated. Of the 104 specimens that could be assessed for the AR, 82 (79%) demonstrated staining. Of 110 lesions, 31 (28%), 42 (38%), and 11 (10%) expressed ERalpha, progesterone receptor, and aromatase, respectively. The level of ERbeta expression was not associated with patient age (P = 0.92), sex (P = 0.82), a diagnosis of tuberous sclerosis (P = 0.56), or histologic subtype of AML (P = 0.94). A trend was found toward increased AR expression in men (P = 0.069) and younger patients (P = 0.052), and ERalpha was expressed in the AML specimens from 5 (71%) of 7 patients with tuberous sclerosis compared with 26 (25%) of 103 without tuberous sclerosis (P = 0.018). Both AR and ERalpha expression were more common in the triphasic subtype of AML than in the lipomatous tumors (P = 0.046 for both).

CONCLUSIONS

The results of our study have shown that ERbeta expression is ubiquitous in renal AML, and the AR is found in most tumors. ERalpha and progesterone receptor were expressed in approximately one third of cases. These data suggest a potential role for hormones in the pathogenesis and management of renal AML.

Sex differences and estrogen modulation of the cellular immune response after injury

Cell-mediated immunity is extremely important for resolution of infection and for proper healing from injury. However, the cellular immune response is dysregulated following injuries such as burn and hemorrhage. Sex hormones are known to regulate immunity, and a well-documented dichotomy exists in the immune response to injury between the sexes. This disparity is caused by differences in immune cell activation, infiltration, and cytokine production during and after injury. Estrogen and testosterone can positively or negatively regulate the cellular immune response either by aiding in resolution or by compounding the morbidity and mortality. It is apparent that the hormonal dysregulation is dependent not only on the type of injury sustained but also the amount of circulating hormones. Therefore, it may be possible to design sex-specific therapies to improve immunological function and patient outcome.

Mechanism of the divergent effects of estrogen on the cell proliferation of human umbilical endothelial versus aortic smooth muscle cells

Diverse estrogen actions are controlled via estrogen receptors (ERs). Mechanisms of action of ERs are modulated by various factors such as ER subtypes, conformation of the ER-ligand complex, and recruitment of coregulator complexes to a target gene promoter. Estrogen exerts divergent actions on vascular cells; namely it increases endothelial cell and inhibits smooth muscle cell growth, resulting in a vasoprotective action. We particularly focused on these divergent effects and examined the mechanisms. The effects of raloxifene, which shows estrogen-like vasoprotective actions, were also examined. To examine the effects of 17beta-estradiol (E(2)) and raloxifene on human aortic smooth muscle cells (HASMCs) and human umbilical venous endothelial cells (HUVECs), we evaluated the effect of E(2) and raloxifene on transcriptional activity, recruitment of the coregulator complex to a target gene promoter, and acetylation of histone of both the IGF-I and COX-2 genes. Treatment with E(2) or raloxifene increased both IGF-I and cyclooxygenase (COX)-2 mRNA expression in HUVECs, whereas they attenuated the serum-induced increase of these genes in HASMCs. Treatment by E(2) and raloxifene induced recruitment of coactivator complex and histone acetylation at both the IGF-I and COX-2 gene promoter in HUVECs. In contrast, in HASMCs, E(2), and raloxifene attenuated the serum-induced recruitment of coactivator complexes and histone acetylation at both the IGF-I and COX-2 gene promoters. Estrogen and raloxifene exert divergent transcriptional regulation on both mRNA expression and the remodeling of IGF-I and COX-2 gene promoters in HUVECs vs. HASMCs.

Progesterone induces the expression of vascular endothelial growth factor (VEGF) 120 and Flk-1, its receptor, in bovine granulosa cells

Vascular endothelial growth factor (VEGF) isoforms (VEGF 120 and VEGF 164) secreted by granulosa cells are involved in thecal angiogenesis during follicular development in the bovine ovary. The follicular fluid in the developing follicle includes a slight amount of the progesterone. However, the progesterone (P4) effects on VEGF120 and VEGF164 isoforms have not been well characterized in the bovine granulosa cells. We investigated the effects of progesterone on the gene expression of hypoxia-inducible factor 1alpha (HIF-1alpha, transcription factor), VEGF120, VEGF164 and Flk-1, its receptors, in cultured bovine granulosa cells. Messenger RNA expression for HIF-1alpha, VEGF120, VEGF164 and Flk-1 was quantified using real-time PCR methods. The levels of VEGF120, HIF-1alpha and Flk-1 mRNAs were increased significantly by P4 at a concentration of 10 ng/ml. In contrast, the expression of VEGF 164 gene is inhibited by P4. The level of VEGF120 and Flk-1 mRNAs in the granulosa cells treated with 10 ng/ml progesterone plus 1 ng/ml estradiol significantly decreased compared with progesterone alone. In contrast, the addition of 1 ng/ml estradiol to the culture medium increased the expression of VEGF164 gene. In conclusion, our data demonstrated that progesterone might stimulate the expression of the VEGF120 via HIF-1alpha, transcription factor, in bovine granulosa cells. These results suggest the hormone-dependent expression pattern of VEGF isoforms during follicular development. Thus, our study suggested the expression of VEGF isoforms in granulosa cells might be controlled by a different pathway during follicle development in cow.

Gelatin microspheres encapsulated with a nonpeptide angiogenic agent, ginsenoside Rg1, for intramyocardial injection in a rat model with infarcted myocardium

Angiogenic therapies may need to select a stable agent to be delivered. In the study, a nonpeptide angiogenic agent, ginsenoside Rg(1) (Rg(1)), was encapsulated in the gelatin microspheres (MSs) crosslinked with genipin and intramuscularly injected into a rat model with infarcted myocardium. bFGF was used as a control. After swelling in an aqueous environment, the MSs without crosslinking became collapsed and stuck together. For those crosslinked, the swollen MSs appeared to be more stable with an increasing the degree of crosslinking. After it was released from MSs in vitro, the remaining activity of bFGF on HUVEC proliferation reduced significantly, while that of Rg(1) remained constant. An inspection of the retrieved hearts revealed a large aneurysmal left ventricle (LV) with a thinned myocardium and a significant myocardial fibrosis for that treated with the Empty MSs (without drug encapsulation). However, those receiving the MSs encapsulated with bFGF or Rg(1) attenuated the enlargement of the LV cavity and the development of myocardial fibrosis. The densities of microvessels found in the border zones of the infarct treated with the bFGF or Rg(1) MSs were significantly greater than that treated with the Empty MSs. These results indicated that Rg(1), a stable angiogenic agent, successfully enhanced the myocardial perfusion and preserved the infarcted LV function.

The hormonal regulation of cutaneous wound healing

Conditions of impaired wound healing in the elderly are associated with substantial morbidity and mortality and impose a significant financial burden upon the world's health services. The findings of a series of recent studies have served to highlight the contrasting contributions made by sex steroid hormones to the regulation of cutaneous repair processes. Although estrogens accelerate healing, the actions of the "male" sex hormones 5alpha-dihydrotestosterone and testosterone are primarily deleterious. The shift that occurs in the balance between serum estrogen and androgen levels as a normal feature of human aging may therefore have important consequences for fundamental tissue repair processes.

Estrogen induces endothelial progenitor cells proliferation and migration by estrogen receptors and PI3K-dependent pathways

Estrogen induces endothelial progenitor cells (EPCs) migration and proliferation, which may serve as a potential target for coronary artery disease, but the mechanisms are unclear. We hypothesized that estrogen receptors (ERs) and phosphatidylinositol 3-kinase (PI3K) signaling pathway, which represent particularly important roles of action for estrogen, may contribute to estrogen-induced EPCs migration and proliferation. Bone marrow mononuclear cells (MNCs) were cultured in Dulbecco's modified Eagle's medium (DMEM) supplemented with growth factors as previously described. A total of 87.32+/-5.13% of adherent cells showed uptake of acetylated low-density lipoprotein and lectin binding. Immunostaining and fluorescence activated cell sorting confirmed the endothelial progenitor phenotype. RT-PCR, immunocytochemistry staining and Western blot demonstrated expression of ERs. Exposure to 17beta-estradiol significantly improved EPCs migration and proliferation. Those effects were blocked by pretreatment with the pharmacological PI3K blockers LY294002 (1 h, 10 micromol/L) and ICI-182780 (1 h, 10 micromol/L), a specific estrogen receptor antagonist, which show involvement of estrogen receptors and PI3K pathway. These results suggest that estrogen induces EPCs migration and proliferation via ERs and PI3K pathway which provided a novel insight and treatment strategy of vascular biology.

Systemic stromal effects of estrogen promote the growth of estrogen receptor-negative cancers

Numerous hormonal factors contribute to the lifetime risk of breast cancer development. These include inherited genetic mutations, age of menarche, age of menopause, and parity. Inexplicably, there is evidence indicating that ovariectomy prevents the formation of both estrogen receptor (ER)-positive and ER-negative breast cancers, suggesting that ER-negative breast cancers are dependent on ovarian hormones for their formation. To examine the mechanism(s) by which this may be occurring, we investigated the hypothesis that steroid hormones promote the outgrowth of ER-negative cancers by influencing host cell types distinct from the mammary epithelial cells. We used a novel xenograft mouse model of parturition-induced breast carcinoma formation, in which the tumors that arise following pregnancy lack the expression of nuclear hormone receptors, thereby recapitulating many clinical cases of this disease. Despite lacking ER expression, the tumors arising following pregnancy in this model require circulating estrogens for their formation. Moreover, increasing the levels of circulating estrogens sufficed to promote the formation and progression of ER-negative cancers, which was accompanied by a systemic increase in host angiogenesis and was attendant with the recruitment of bone marrow-derived stromal cells. Furthermore, bone marrow cells from estrogen-treated mice were sufficient to promote tumor growth. These results reveal a novel mechanism by which estrogens promote the growth of ER-negative cancers.

Angiogenic factors in normal endometrium and endometrial adenocarcinoma

In the endometrium, angiogenesis plays important roles not only in tumor growth but also in the menstrual cycle. The purpose of the present paper was to investigate immunohistochemically the correlation between angiogenic factor expression and angiogenic score in normal and neoplastic endometrium. Immunohistochemical staining for vascular endothelial growth factor (VEGF), angiopoietin (Ang)-1, Ang2, Tie2, CD34 and CD105 was performed on formalin-fixed and paraffin-embedded tissues from 31 normal endometrium and 85 endometrial adenocarcinoma. VEGF, Ang1, Ang2 and Tie2 expression was localized in the cytoplasm of glandular and tumor cells. The levels of each angiogenic factor were different in the phases of the menstrual cycle and each layer of normal endometrium. In general, VEGF and Tie2 expression was higher in adenocarcinoma than in normal epithelial cells. Conversely, Ang1 and Ang2 expression was higher in normal epithelium than in adenocarcinoma. The angiogenic score (CD105/CD34) tended to be higher in the adenocarcinoma than in the normal epithelium. It is suggested that the angiogenic pathway and the role of these factors seem to differ between normal tissue and carcinoma of the endometrium.

Bevacizumab for Advanced Breast Cancer

Tumor angiogenesis is essential for the growth and metastasis of solid tumors. In breast cancer, increased levels of vascular endothelial growth factor (VEGF) have been associated with poor prognosis in lymph node-positive and lymph node-negative patients. In addition to its prognostic significance, VEGF is now a validated target in the treatment of breast cancer. Bevacizumab, an anti-VEGF antibody, has demonstrated significant clinical benefit in several solid tumors. In this article the authors discuss the data pertaining to bevacizumab and other antiangiogenic agents for the treatment of patients who have advanced breast cancer.