Vascular endothelial growth factors are differentially regulated by steroid hormones and antiestrogens in breast cancer cells

Differential effects of proton pump inhibitors and vonoprazan on vascular endothelial growth factor expression in cancer cells

Proton pump inhibitors (PPIs) are potent inhibitors of gastric acid secretion, used as first-line agents in treating peptic ulcers. However, we have previously reported that PPIs may diminish the therapeutic effect of anti-vascular endothelial growth factor (VEGF) drugs in patients with cancer. In this study, we explored the effects of vonoprazan, a novel gastric acid secretion inhibitor used for the treatment of peptic ulcers, on the secretion of VEGF in cancer cells and attempted to propose it as an alternative PPI for cancer chemotherapy. The effects of PPI and vonoprazan on VEGF expression in cancer cells were compared by real-time reverse transcription-polymerase chain reaction and ELISA. The interaction of vonoprazan and PPIs with transcriptional regulators by docking simulation analysis. In various cancer cell lines, including the human colorectal cancer cell line (LS174T), PPI increased VEGF messenger RNA expression and VEGF protein secretion, while this effect was not observed with vonoprazan. Molecular docking simulation analysis showed that vonoprazan had a lower binding affinity for estrogen receptor alpha (ER-α), one of the transcriptional regulators of VEGF, compared to PPI. Although the PPI-induced increase in VEGF expression was counteracted by pharmacological ER-α inhibition, the effect of vonoprazan on VEGF expression was unchanged. Vonoprazan does not affect VEGF expression in cancer cells, which suggests that vonoprazan might be an alternative to PPIs, with no interference with the therapeutic effects of anti-VEGF cancer chemotherapy.

Assessing Whether Morphological Changes in Axillary Lymph Node Have Already Occurred Prior to Metastasis in Breast Cancer Patients by Ultrasound

Background and Objectives: Whether the morphological changes in axillary lymph node (ALN) have occurred prior to metastasis remains unclear in breast cancer (BC) patients. The aim of this study is to investigate the influence of BC for the morphology of non-metastasis ALN (N−) and, further, to improve the performance of ultrasound (US) examination for metastasis ALN (N+). Materials and Methods: In this retrospective study, 653 patients with breast mass were enrolled and divided into normal group of 202 patients with benign breast tumor, N− group of 233 BC patients with negative ALN and N+ group of 218 BC patients with positive ALN. US features of ALN were evaluated and analyzed according to long (L) and short (S) diameter, the (L/S) axis ratio, cortical thickness, lymph node edge, replaced hilum and color Doppler flow imaging (CDFI). Results: ALN US features of short diameter, replaced hilum, cortical thickness and CDFI have significant statistical differences in N− group comparing with normal group and N+ group, respectively (p < 0.05). Conclusions: Therefore, BC can affect ALN and lead to US morphological changes whether lymph node metastasis is present, which reduces the sensitivity of axillary US. The combination of US and other examination methods should be applied to improve the diagnostic performance of N+.

Research progress of bile biomarkers and their immunoregulatory role in biliary tract cancers

Biliary tract cancers (BTCs), including cholangiocarcinoma and gallbladder carcinoma, originate from the biliary epithelium and have a poor prognosis. Surgery is the only choice for cure in the early stage of disease. However, most patients are diagnosed in the advanced stage and lose the chance for surgery. Early diagnosis could significantly improve the prognosis of patients. Bile has complex components and is in direct contact with biliary tract tumors. Bile components are closely related to the occurrence and development of biliary tract tumors and may be applied as biomarkers for BTCs. Meanwhile, arising evidence has confirmed the immunoregulatory role of bile components. In this review, we aim to summarize and discuss the relationship between bile components and biliary tract cancers and their ability as biomarkers for BTCs, highlighting the role of bile components in regulating immune response, and their promising application prospects.

Evaluation of Different Doses of the Aromatase Inhibitor Letrozole for the Treatment of Ectopic Pregnancy and Its Effect on Villous Trophoblastic Tissue

Letrozole, an aromatase inhibitor, has recently been introduced as a favorable medical treatment for ectopic pregnancy. We aimed at evaluating the effects of different doses of letrozole for termination of ectopic pregnancy and study their effects on villous trophoblastic tissue. Sixty patients with undisturbed ectopic pregnancy were classified into three equal groups. Group I: the control group that contained women who underwent laparoscopic salpingectomy, Group II: patients who received letrozole (5 mg day⁻¹) for 10 days, and Group III: patients who received letrozole (10 mg day⁻¹) for 10 days. Subsequently, the β-hCG levels were determined on the first day and after 11 days of treatment. Group IV consisted of patients of GII and GIII; their β-hCG did not drop below 100 mIU/ml within 11 days, and underwent salpingectomy. Placental tissues from patients undergoing salpingectomy either from the control group or GIV were processed for the evaluation of estrogen (ER) and progesterone (PR) receptors, vascular endothelial growth factor (VEGF), and cleaved caspase 3 (CC-3) expression. Cases exposed to high dose letrozole 10 mg day⁻¹ resulted in a higher ectopic pregnancy resolution rate of 85% (17/20), while the resolution rate of the low dose letrozole-treated group (5 mg day⁻¹) was 65% (13/20), and also showed a significant reduction in β-hCG levels on the 11th day, 25.63 ± 4.29 compared to the low dose letrozole group 37.91 ± 7.18 (P < 0.001), Meanwhile, the letrozole-treated group GIV showed markedly reduced expression of ER, PR, and VEGF and a significant increase in the apoptotic index cleaved caspase-3 compared to the control group (P < 0.001). The utilization of letrozole at a dose of 10 mg day⁻¹ for medical treatment of ectopic pregnancy results in a high-successful rate without any severe side effects. Letrozole depriving the placenta of estrogen that had vascular supporting signals resulted in destroying the vascular network with marked apoptosis.

The Endocrine Disruptor Compound Bisphenol-A (BPA) Regulates the Intra-Tumoral Immune Microenvironment and Increases Lung Metastasis in an Experimental Model of Breast Cancer

Simple Summary

The widely spread microplastic component and endocrine disruptor BPA is a hazardous material recognized for a long time. Here, for the first time, we demonstrated that BPA, administered into mice in a very specific developmental step of the animal (3 days post-natal), induces an increase in metastasis to the lung in the adult life, compared to the control or vehicle mice. In addition, of novelty, it is the analysis of the cytokine tumor microenvironment, which is the reason for the increased metastasis by BPA (BPA induce the increase in pro-metastatic cytokines).

Abstract

Breast cancer (BC) metastasis represents the main physiopathology leading to poor prognosis and death. Bisphenol A (BPA) is a pollutant, classified as an endocrine-disrupting chemical compound with estrogenic properties, their exposure in the early stages of neonatal life leads to an increase in the size and weight of breast tumors and induces cellular changes in the tumoral immune microenvironment where cytokines play a key role. Thus, we used female BALB/c mice exposed neonatally to a single dose of BPA. Once mice reached sexual maturity, a mammary tumor was induced, injecting 4T1 cells in situ. After 25 days of injection, we evaluated endocrine alterations, cytokine expression, tissue alterations denoted by macro or micro-metastasis in the lung, and cell infiltration induced by metastasis. We found that BPA neonatal treatment did not show significant endocrine alterations. Noteworthy, BPA led to an augmented rate of metastasis to the lung associated with higher intratumoral expression of IL-1β, IL-6, IFN-γ, TNF-α, and VEGF. Our data suggest that cytokines are key players in the induction of BC metastasis and that BPA (an environmental pollutant) should be considered as a risk factor in the clinical history of patients as a possible inductor of BC metastasis.

Three dimensional engineered models to study hypoxia biology in breast cancer

Breast cancer is the second leading cause of mortality among women worldwide. Despite the available therapeutic regimes, variable treatment response is reported among different breast cancer subtypes. Recently, the effects of the tumor microenvironment on tumor progression as well as treatment responses have been widely recognized. Hypoxia and hypoxia inducible factors in the tumor microenvironment have long been known as major players in tumor progression and survival. However, the majority of our understanding of hypoxia biology has been derived from two dimensional (2D) models. Although many hypoxia-targeted therapies have elicited promising results in vitro and in vivo, these results have not been successfully translated into clinical trials. These limitations of 2D models underscore the need to develop and integrate three dimensional (3D) models that recapitulate the complex tumor-stroma interactions in vivo. This review summarizes role of hypoxia in various hallmarks of cancer progression. We then compare traditional 2D experimental systems with novel 3D tissue-engineered models giving accounts of different bioengineering platforms available to develop 3D models and how these 3D models are being exploited to understand the role of hypoxia in breast cancer progression.

Activation of HIF-1α by δ-Opioid Receptors Induces COX-2 Expression in Breast Cancer Cells and Leads to Paracrine Activation of Vascular Endothelial Cells

Opioids promote tumor angiogenesis in mammary malignancies, but the underlying signaling mechanism is largely unknown. The current study investigated the hypothesis that stimulation of δ-opioid receptors (DOR) in breast cancer (BCa) cells activates the hypoxia-inducible factor 1α (HIF-1α), which triggers synthesis and release of diverse angiogenic factors. Immunoblotting revealed that incubation of human MCF-7 and T47D breast cancer cells with the DOR agonist d-Ala²,d-Leu⁵-enkephalin (DADLE) resulted in a transient accumulation and thus activation of HIF-1α DADLE-induced HIF-1α activation preceded PI3K/Akt stimulation and was blocked by the DOR antagonist naltrindole and naloxone, pertussis toxin, different phosphoinositide 3-kinase (PI3K) inhibitors, and the Akt inhibitor Akti-1/2. Whereas DADLE exposure had no effect on the expression and secretion of vascular endothelial growth factor (VEGF) in BCa cells, an increased abundance of cyclooxygenase-2 (COX-2) and release of prostaglandin E2 (PGE₂) was detected. DADLE-induced COX-2 expression was also observed in three-dimensional cultured MCF-7 cells and impaired by PI3K/Akt inhibitors and the HIF-1α inhibitor echinomycin. Supernatant from DADLE-treated MCF-7 cells triggered sprouting of endothelial (END) cells, which was blocked when MCF-7 cells were pretreated with echinomycin or the COX-2 inhibitor celecoxib. Also no sprouting was observed when END cells were exposed to the PGE₂ receptor antagonist PF-04418948. The findings together indicate that DOR stimulation in BCa cells leads to PI3K/Akt-dependent HIF-1α activation and COX-2 expression, which trigger END cell sprouting by paracrine activation of PGE₂ receptors. These findings provide a potential mechanism of opioid-driven tumor angiogenesis and thus therapeutic targets to combat the tumor-angiogenic opioid effect. SIGNIFICANCE STATEMENT: Opioids are indispensable analgesics for treating cancer-related pain. However, opioids were found to promote tumor growth and metastasis, which questions the use of these potent pain-relieving drugs in cancer patients. Enhanced tumor vascularization after opioid treatment implies that tumor progression results from angiogenic opioid effects. Thus, understanding the signaling mechanism of opioid-driven tumor angiogenesis helps to identify therapeutic targets to combat these undesired tumor effects. The present study reveals that stimulation of δ-opioid receptors in breast cancer cells leads to an activation of HIF-1α and expression of COX-2 via PI3K/Akt stimulation, which results in a paracrine activation of vascular endothelial cells by prostaglandin E₂ receptors.

Role of the Angiogenic Factors in Cholangiocarcinoma

Angiogenesis plays a fundamental role in tumor growth and progression. It is regulated by several growth factors, including vascular endothelial growth factor protein family (VEGF) and its receptors, which are probably the most important factors responsible for the development of new vessels. The VEGF family includes several members: VEGF-A, VEGF-B, VEGF-C, VEGF-D, VEGF-E, placental growth factor (PlGF), and their receptors VEGFR-1, VEGFR-2 and VEGFR-3. Other relevant factors are represented by angiopoietins, thrombospondin-1, and endothelins. However, since the therapeutic benefit associated with VEGF-targeted therapy is really complex, a better understanding of these pathways will lead to future advances in the use of these agents for clinic management of tumors. Here we present a review regarding the role of angiogenic factors in cholangiocarcinoma, which arise from cholangiocytes, the epithelial cells of bile ducts. They are rare and aggressive neoplasms with a poor prognosis and limited treatment options, classified as intrahepatic, perihilar, and distal cholangiocarcinoma based on their anatomical location. Therefore, the identification of specific signaling pathways or new tumor biomarkers is crucial in order to develop more effective anti-angiogenic therapies.

Hormone Therapy and Breast Cancer: Emerging Steroid Receptor Mechanisms

Although hormone therapy is widely used by millions of women to relieve symptoms of menopause, it has been associated with several side-effects such as coronary heart disease, stroke and increased invasive breast cancer risk. These side-effects have caused many women to seek alternatives to conventional hormone therapy, including the controversial custom-compounded bioidentical hormone therapy suggested to not increase breast cancer risk. Historically estrogens and the estrogen receptor were considered the principal factors promoting breast cancer development and progression, however, a role for other members of the steroid receptor family in breast cancer pathogenesis is now evident, with emerging studies revealing an interplay between some steroid receptors. In this review, we discuss examples of hormone therapy used for the relief of menopausal symptoms, highlighting the distinction between conventional hormone therapy and custom-compounded bioidentical hormone therapy. Moreover, we highlight the fact that not all hormones have been evaluated for an association with increased breast cancer risk. We also summarize the current knowledge regarding the role of steroid receptors in mediating the carcinogenic effects of hormones used in menopausal hormone therapy, with special emphasis on the influence of the interplay or crosstalk between steroid receptors. Unraveling the intertwined nature of steroid hormone receptor signaling pathways in breast cancer biology is of utmost importance, considering that breast cancer is the most prevalent cancer among women worldwide. Moreover, understanding these mechanisms may reveal novel prevention or treatment options, and lead to the development of new hormone therapies that does not cause increased breast cancer risk.

Hypoxia and Hormone-Mediated Pathways Converge at the Histone Demethylase KDM4B in Cancer

Hormones play an important role in pathophysiology. The hormone receptors, such as estrogen receptor alpha and androgen receptor in breast cancer and prostate cancer, are critical to cancer cell proliferation and tumor growth. In this review we focused on the cross-talk between hormone and hypoxia pathways, particularly in breast cancer. We delineated a novel signaling pathway from estrogen receptor to hypoxia-inducible factor 1, and discussed the role of this pathway in endocrine therapy resistance. Further, we discussed the estrogen and hypoxia pathways converging at histone demethylase KDM4B, an important epigenetic modifier in cancer.

The role of vascular endothelial growth factor-B in metabolic homoeostasis: current evidence

It has been shown that adipose tissue and skeletal muscles in lean individuals respond to meal-induced hyperinsulinemia by increase in perfusion, the effect not observed in patients with metabolic syndrome. In conditions of hyperglycaemia and hypertriglyceridemia, this insufficient vascularization leads to the liberation of reactive oxygen species (ROS), and disruption of nitric oxide (NO) synthesis and endothelial signalling responsible for the uptake of circulating fatty acids (FAs), whose accumulation in skeletal muscles and adipose tissue is widely associated with the impairment of insulin signalling. While the angiogenic role of VEGF-A and its increased circulating concentrations in obesity have been widely confirmed, the data related to the metabolic role of VEGF-B are diverse. However, recent discoveries indicate that this growth factor may be a promising therapeutic agent in patients with metabolic syndrome. Preclinical studies agree over two crucial metabolic effects of VEGF-B: (i) regulation of FAs uptake and (ii) regulation of tissue perfusion via activation of VEGF-A/vascular endothelial growth factor receptor (VEGFR) 2 (VEGFR2) pathway. While in some preclinical high-fat diet studies, VEGF-B overexpression reverted glucose intolerance and stimulated fat burning, in others it further promoted accumulation of lipids and lipotoxicity. Data from clinical studies point out the changes in circulating or tissue expression levels of VEGF-B in obese compared with lean patients. Potentially beneficial effects of VEGF-B, achieved through enhanced blood flow (increased availability of insulin and glucose uptake in target organs) and decreased FAs uptake (prevention of lipotoxicity and improved insulin signalling), and its safety for clinical use, remain to be clarified through future translational research.

Hypoxia reduces testosterone synthesis in mouse Leydig cells by inhibiting NRF1-activated StAR expression

Male fertility disorders play a key role in half of all infertility cases. Reduction in testosterone induced by hypoxia might cause diseases in reproductive system and other organs. Hypoxic exposure caused a significant decrease of NRF1. Software analysis reported that the promoter region of steroidogenic acute regulatory protein (StAR) contained NRF1 binding sites, indicating NRF1 promoted testicular steroidogenesis. The purpose of this study is to determine NRF1 is involved in testosterone synthesis; and under hypoxia, the decrease of testosterone synthesis is caused by lower expression of NRF1. We designed both in vivo and in vitro experiments. Under hypoxia, the expressions of NRF1 in Leydig cells and testosterone level were significantly decreased both in vivo and in vitro. Overexpression and interference NRF1 could induced StAR and testosterone increased and decreased respectively. ChIP results confirmed the binding of NRF1 to StAR promoter region. In conclusion, decline of NRF1 expression downregulated the level of StAR, which ultimately resulted in a reduction in testosterone synthesis.

Molecular expression of vascular endothelial growth factor, prokineticin receptor-1 and other biomarkers in infiltrating canalicular carcinoma of the breast

Vascular endothelial growth factor (VEGF) is important in the growth and metastasis of cancer cells. In 2001, another angiogenic factor, endocrine gland-derived VEGF (EG-VEGF), was characterized and sequenced. EG-VEGF activity appears to be restricted to endothelial cells derived from endocrine glands. At the molecular level, its expression is regulated by hypoxia and steroid hormones. Although VEGF and EG-VEGF are structurally different, they function in a coordinated fashion. Since the majority of mammary tumors are hormone-dependent, it was hypothesized that EG-VEGF would be expressed in these tumors, and therefore, represent a potential target for anti-angiogenic therapy. The aim of the present study was to assess the expression of VEGF, EG-VEGF and its receptor (prokineticin receptor-1), as well as that of breast cancer resistant protein, estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2, in 50 breast samples of infiltrating canalicular carcinoma (ICC) and their correlation with tumor staging. The samples were analyzed using reverse transcription-quantitative polymerase chain reaction and immunohistochemistry. Both angiogenic growth factors were identified in all samples. However, in 90% of the samples, the expression level of VEGF was significantly higher than that of EG-VEGF (P=0.024). There was no association between the expression of VEGF, EG-VEGF or its receptor with tumor stage. In ICC, the predominant angiogenic factor expressed was VEGF. The expression level of either factor was not correlated with the tumor-node-metastasis stage. Although ICC is derived from endothelial cells, EG-VEGF expression was not the predominant angiogenic/growth factor in ICC.

MicroRNA-206, let-7a and microRNA-21 pathways involved in the anti-angiogenesis effects of the interval exercise training and hormone therapy in breast cancer

AIMS

MicroRNAs (miRNAs) are the targeting signal-transduction pathways that can mediate tumorigenesis via their down and/or up-regulation. For example, miR-21 and miR-206 can effect on the tumor angiogenesis as an oncomir and a tumor suppressor, respectively.

MATERIALS AND METHODS

The present study is aimed to investigate the effects of the interval exercise training in combination with tamoxifen and/or letrozole on miR-21, miR-206 and let-7 as well as their underlying pathways in regard to tumor angiogenesis in sixty four mice with breast tumor. ELISA, immunohistochemistry, qRT-PCR assays were performed accomplish the study.

KEY FINDINGS

The results showed that the tumor size was significantly declined in the exercise training, tamoxifen and letrozole groups compared to tumor group. Mir-206 and let-7 were up-regulated, and mir-21 expression was down-regulated in the exercise training compared to tumor group. Exercise training decreased the expression of ER-α, HIF-α, VEGF, CD31 and Ki67 in tumor tissue. The combination tamoxifen and/or letrozole with the exercise training could down-regulate the expression of ERα, miR-21, HIF-1α, TNF-α, CD31, Ki67 and VEGF, and up-regulate the expression of miR-206, PDCD-4, let-7 and IL-10 that led to reducing the angiogenesis and tumor growth.

SIGNIFICANCE

Our results showed that miR-21, miR-206 and let-7a pathways may involve in the anti-angiogenesis effects of the interval exercise training with hormone therapy in mice model of breast tumor.

Pim Kinases Promote Migration and Metastatic Growth of Prostate Cancer Xenografts

Background and methods

Pim family proteins are oncogenic kinases implicated in several types of cancer and involved in regulation of cell proliferation, survival as well as motility. Here we have investigated the ability of Pim kinases to promote metastatic growth of prostate cancer cells in two xenograft models for human prostate cancer. We have also evaluated the efficacy of Pim-selective inhibitors to antagonize these effects.

Results

We show here that tumorigenic growth of both subcutaneously and orthotopically inoculated prostate cancer xenografts is enhanced by stable overexpression of either Pim-1 or Pim-3. Moreover, Pim-overexpressing orthotopic prostate tumors are highly invasive and able to migrate not only to the nearby prostate-draining lymph nodes, but also into the lungs to form metastases. When the xenografted mice are daily treated with the Pim-selective inhibitor DHPCC-9, both the volumes as well as the metastatic capacity of the tumors are drastically decreased. Interestingly, the Pim-promoted metastatic growth of the orthotopic xenografts is associated with enhanced angiogenesis and lymphangiogenesis. Furthermore, forced Pim expression also increases phosphorylation of the CXCR4 chemokine receptor, which may enable the tumor cells to migrate towards tissues such as the lungs that express the CXCL12 chemokine ligand.

Conclusions

Our results indicate that Pim overexpression enhances the invasive properties of prostate cancer cells in vivo. These effects can be reduced by the Pim-selective inhibitor DHPCC-9, which can reach tumor tissues without serious side effects. Thus, Pim-targeting therapies with DHPCC-9-like compounds may help to prevent progression of local prostate carcinomas to fatally metastatic malignancies.

Effect of varying doses of tamoxifen on ovarian histopathology, serum VEGF, and endothelin 1 levels in ovarian hyperstimulation syndrome: an experimental study

OBJECTIVE

To examine the effects of low-to-high doses of tamoxifen on ovarian histopathology, serum VEGF, and endothelin 1 levels in ovarian hyperstimulation syndrome (OHSS) in an experimental setting.

MATERIALS AND METHODS

A total of 20 female Wistar albino rats, 22 days of age, were randomly divided into four groups. Follicle-stimulating hormone 10 IU was administered subcutaneously in 15 rats on 4 consecutive days, with OHSS induction on day 5 by 30 IU of human chorionic gonadotropin. Group 1 (n=5) comprised 35-day-old control rats, group 2 (n=5) 35-day-old OHSS rats, group 3 (n=5) 27-day-old OHSS rats receiving 1 mg/kg of oral tamoxifen for 7 days, group 4 (n=5) 27-day-old OHSS rats receiving 3 mg/kg of oral tamoxifen for 7 days. All rats were decapitated on day 35. Serum VEGF, endothelin 1, and ovarian follicular reserve were assessed in all rats. Kruskal-Wallis variance analysis and the Mann-Whitney U-test were used for statistical comparisons. A Bonferroni correction was performed to control the inflation of significance, with a significance level set at a P-value of less than 0.025.

RESULTS

Despite higher serum VEGF, endothelin 1, follicular reserve, and angiogenesis and fibrosis of the corpus luteum in the OHSS group compared to controls, these differences were not significant (P>0.025, Mann-Whitney U-test). There was a significant reduction in the ovarian follicular reserve in tamoxifen groups compared to controls (P<0.025, Mann-Whitney U-test), while angiogenesis of the corpus luteum, number of atretic follicles, fibrosis, and serum VEGF were significantly higher in rats receiving tamoxifen (P<0.025, Mann-Whitney U-test). Also, significantly lower follicular reserve and fibrosis were observed among rats in the low-dose tamoxifen group in comparison with rats in the high-dose tamoxifen group (P<0.025, Mann-Whitney U-test). No groups had a significant change in endothelin 1 levels (P>0.025, Mann-Whitney U-test).

CONCLUSION

Tamoxifen 1 g and 3 g resulted in a dose-dependent increase in VEGF and endothelin 1 levels, and ovarian follicle reserves were significantly reduced in our experimental model.

Dynamics of IGF-1R expression during endocrine breast cancer treatment

PURPOSE

The aim was to assess changes in insulin-like growth factor 1 receptor (IGF-1R) expression with immunoSPECT/CT and to study the dynamics of IGF-1R expression of human breast tumors during endocrine treatment.

PROCEDURES

Mice with MCF-7 xenografts were treated with estradiol or tamoxifen, and IGF-1R expression was measured by immunohistochemistry and immunoSPECT/CT using (111)In-R1507 (anti-IGF-1R antibody). Moreover, IGF-1R expression was analyzed immunohistochemically on 22 human breast tumors, treated preoperatively with endocrine therapy.

RESULTS

Estradiol resulted in an increased expression of IGF-1R, as measured by immunohistochemistry and immunoSPECT/CT. In contrast, tamoxifen resulted in a downregulation of IGF-1R, whereas this could not be measured with immunoSPECT/CT. A downregulation was also detectable in 9 out of 22 (41 %) human breast tumors after endocrine therapy.

CONCLUSIONS

Anti-estrogen treatment can cause a reduction in membranous IGF-1R expression. Based on these results, a combination of anti-IGF-1R antibodies with anti-estrogen therapy might not be a rational treatment strategy.

Molecular mechanisms of hormone resistance of breast cancer

More than 70% malignant mammary tumors contain steroid hormone receptors; this suggests the possibility of hormone therapy in the majority of patients with breast cancer (BC). The main cause of inefficiency of hormone therapy in BC is hormone resistance (tumor resistance to hormonal cytostatics). Here we discuss the main mechanisms of hormone resistance of BC and the mechanisms underlying the formation of hormone resistance of the tumors are analyzed at the molecular level. The data on the signal pathways of estrogen receptors (ER), the key regulators of BC cell proliferation, are presented. The most important factors of BC hormone resistance are: high activity/expression of receptor tyrosine kinases; high activity of proteins regulating cell defense mechanisms (Akt PI3K, mTOR); changes in the activities of cell cycle regulator proteins (Myc, c-Fos, Cyclin D1). Our experiments have demonstrated that estrogen-independent BC cell growth is supported by VEGF/VEGFR2 and EGF/EGFR mitogenic signal pathways. Our data indicate that NF-kappaB transcription factor is directly involved in the regulation of hormone-resistant BC cell growth and survival, while NF-kappaB suppression determines cell sensitivity to apoptotic activity of antitumor compounds. On the whole, the results indicate good prospects of using EGFR, HER-2/neu, mTOR, VEGFR, PI3K/Akt molecular pathways as targets for BC therapy, including therapy for BC resistant forms.

Impact of adding the multikinase inhibitor sorafenib to endocrine therapy in metastatic estrogen receptor-positive breast cancer

BACKGROUND

Targeting growth factor and survival pathways may delay endocrine-resistance in estrogen receptor-positive breast cancer.

MATERIALS & METHODS

A pilot Phase II study adding sorafenib to endocrine therapy in 11 patients with metastatic estrogen receptor-positive breast cancer was conducted. Primary end point was response by RECIST after 3 months of sorafenib. Secondary end points included safety, time to progression and biomarker modulation. The study closed early owing to slow accrual.

RESULTS

Eight out of 11 patients had progressive disease on study entry and three had stable disease. Of the ten evaluable patients, seven experienced stable disease (70%) and three experienced progressive diseas (30%), with a median time to progression of 6.1 months (8.4 months in the seven patients on tamoxifen). The serum samples demonstrated a significant reduction in VEGF receptor 2 and PDGF receptor-α. Microarray analysis identified 32 suppressed genes, no induced genes and 29 enriched Kyoto Encyclopedia of Genes and Genomes pathways.

CONCLUSION

The strategy of adding a targeted agent to endocrine therapy upon resistance may be worthwhile testing in larger studies.

Clinical experience with ramucirumab : outcomes in breast cancer

INTRODUCTION

Monoclonal antibodies and small molecules targeting the VEGF pathway are part of the arsenal to treat malignant tumors. Antiangiogenesis therapies has been studied in breast cancer with partial success, reflected by the approval of bevacizumab in Europe but not in United States, for metastatic breast cancer (mBC). Ramucirumab is a mAb against VEGFR-2 interfering with the normal activation of this receptor by its natural ligand VEGF.

AREAS COVERED

This article will review the preclinical data available to date for ramucirumab, as well as survey the main clinical trials of antiangiogenic agents reported in breast cancer, focusing on Phase III clinical trials. It will also review the clinical trial data for ramucirumab in mBC, including the design of the Phase II trials, and report on the preliminary results of the TRIO-012 trial. This trial did not meet its primary end point in progression-free survival and has to be considered as a negative trial.

EXPERT OPINION

Despite preliminary positive data with ramucirumab in other metastatic solid tumors reported to date, the results of TRIO-012 discourage pursuing more efforts with ramucirumab in mBC unless predictive and reproducible biomarkers can be established to select those patients who are most likely to benefit from it.

COX-2 silencing enhances tamoxifen antitumor activity in breast cancer in vivo and in vitro

Tamoxifen (Tam), a selective estrogen receptor modulator, is in wide clinical use for the treatment and prevention of breast cancer. However, extended TAM administration for breast cancer induces increased VEGF levels in patients, promoting new blood vessel formation and thereby limiting its efficacy and highlighting the need for improved therapeutic strategies. Cyclooxygenase-2 (COX-2) silencing via a replication-incompetent lentivirus (LV-COX-2) induce cancer apoptosis and suppresses VEGF gene expression. In this study, the effect of LV-COX-2 infection, either alone or in combination with TAM, was analyzed in a breast cell lines for suppressing VEGF expression and simultaneously reducing doses of TAM. Cell proliferation, apoptosis, angiogenesis, metastasis, cell cycle distribution, an receptor signaling were determined after LV-COX-2 combination with TAM treatment. In addition, tumor growth ability in nude mice was detected to define the combination treatment effect in tumorigenesis in vivo. It is found that LV-COX-2 combination with TAM treatment in breast cancer cell significantly suppressed the proliferation and metastasis, and induced tumor apoptosis in vitro, and tumor growth also was suppressed in vivo. In addition, we also found that LV-COX-2 combination with TAM treatment could inhibit angiogenesis and VEGF expression. Taken together, our experimental results indicate that LV-COX-2 combination with TAM has promising outcome in anti-metastatic and apoptotic studies. Furthermore, these results showed that LV-COX-2 combination with TAM is a potential drug candidate for treatment of breast tumors expressing high levels of VEGF.

The use of a whole animal biophotonic model as a screen for the angiogenic potential of estrogenic compounds

BACKGROUND

Vascular endothelial growth factor (VEGF) is essential for normal vascular growth and development during wound repair. VEGF is estrogen responsive and capable of regulating its own receptor, vascular endothelial growth factor receptor-2 (VEGFR-2). Several agricultural pesticides (e.g., methoxychlor) have estrogenic potential that can initiate inappropriate physiological responses in estrogenic-sensitive tissues following exposure in vivo. Thus, the current study was designed to determine whether the VEGFR-2-Luciferase (Luc) reporter transgenic mouse is a useful model for evaluating estrogenic tendencies of methoxychlor by monitoring wound healing via VEGFR-2-mediated gene expression using bioluminescence and real-time imaging technology.

RESULTS

VEGFR-2-Luc gene activity peaked by d 7 (P<0.001) in all groups but was not different (P>0.05) between control and estrogen/methoxychlor exposed mice.

CONCLUSIONS

Changes in VEGFR-2-Luc gene activity associated with the dermal wound healing process were able to be measured via photonic emission. The increase in vasculature recruitment and formation is paralleled by the increase of VEGFR-2-Luc activity with a peak on day 7. However, estrogen/methoxychlor did not significantly alter wound healing mediated VEGFR-2-Luc gene expression patterns compared to controls. This suggests that the VEGFR-2-Luc transgenic mouse wound model tested in this study may not be optimal for use as a screen for the angiogenic potential of estrogenic compounds.

Regeneration of breeding tubercles on zebrafish pectoral fins requires androgens and two waves of revascularization

Sexually dimorphic breeding tubercles (BTs) are keratinized epidermal structures that form clusters on the dorsal surface of the anterior rays of zebrafish male pectoral fins. BTs appear during sexual maturation and are maintained through regular shedding and renewal of the keratinized surface. Following pectoral fin amputation, BT clusters regenerate after the initiation of revascularization, but concomitantly with a second wave of angiogenesis. This second wave of regeneration forms a web-like blood vessel network that penetrates the supportive epidermis of BTs. Upon analyzing the effects of sex steroids and their inhibitors, we show that androgens induce and estrogens inhibit BT cluster formation in intact and regenerating pectoral fins. Androgen-induced BT formation in females is accompanied by the formation of a male-like blood vessel network. Treatment of females with both androgens and an angiogenesis inhibitor results in the formation of undersized BT clusters when compared with females treated with androgens alone. Overall, the growth and regeneration of large BTs requires a hormonal stimulus and the presence of an additional blood vessel network that is naturally found in males.

Cyclin A1 modulates the expression of vascular endothelial growth factor and promotes hormone-dependent growth and angiogenesis of breast cancer

Alterations in cellular pathways related to both endocrine and vascular endothelial growth factors (VEGF) may contribute to breast cancer progression. Inhibition of the elevated levels of these pathways is associated with clinical benefits. However, molecular mechanisms by which endocrine-related pathways and VEGF signalling cooperatively promote breast cancer progression remain poorly understood. In the present study, we show that the A-type cyclin, cyclin A1, known for its important role in the initiation of leukemia and prostate cancer metastasis, is highly expressed in primary breast cancer specimens and metastatic lesions, in contrasting to its barely detectable expression in normal human breast tissues. There is a statistically significant correlation between cyclin A1 and VEGF expression in breast cancer specimens from two patient cohorts (p<0.01). Induction of cyclin A1 overexpression in breast cancer cell line MCF-7 results in an enhanced invasiveness and a concomitant increase in VEGF expression. In addition, there is a formation of protein–protein complexes between cyclin A1 and estrogen receptor ER-α cyclin A1 overexpression increases ER-α expression in MCF-7 and T47D cells. In mouse tumor xenograft models in which mice were implanted with MCF-7 cells that overexpressed cyclin A1 or control vector, cyclin A1 overexpression results in an increase in tumor growth and angiogenesis, which is coincident with an enhanced expression of VEGF, VEGFR1 and ER-α Our findings unravel a novel role for cyclin A1 in growth and progression of breast cancer, and suggest that multiple cellular pathways, including cell cycle regulators, angiogenesis and estrogen receptor signalling, may cooperatively contribute to breast cancer progression.

Celecoxib alleviates tamoxifen-instigated angiogenic effects by ROS-dependent VEGF/VEGFR2 autocrine signaling

BACKGROUND

Tamoxifen (TAM) is widely used in the chemotherapy of breast cancer and as a preventive agent against recurrence after surgery. However, extended TAM administration for breast cancer induces increased VEGF levels in patients, promoting new blood vessel formation and thereby limiting its efficacy. Celecoxib (CXB), a selective COX-2 inhibitor, suppresses VEGF gene expression by targeting the VEGF promoter responsible for its inhibitory effect. For this study, we had selected CXB as non-steroidal anti-inflammatory drug in combination with TAM for suppressing VEGF expression and simultaneously reducing doses of both the drugs.

METHODS

The effects of CXB combined with TAM were examined in two human breast cancer cell lines in culture, MCF7 and MDA-MB-231. Assays of proliferation, apoptosis, angiogenesis, metastasis, cell cycle distribution, and receptor signaling were performed.

RESULTS

Here, we elucidated how the combination of TAM and CXB at nontoxic doses exerts anti-angiogenic effects by specifically targeting VEGF/VEGFR2 autocrine signaling through ROS generation. At the molecular level, TAM-CXB suppresses VHL-mediated HIF-1α activation, responsible for expression of COX-2, MMP-2 and VEGF. Besides low VEGF levels, TAM-CXB also suppresses VEGFR2 expression, confirmed through quantifying secreted VEGF levels, luciferase and RT-PCR studies. Interestingly, we observed that TAM-CXB was effective in blocking VEGFR2 promoter induced expression and further 2 fold decrease in VEGF levels was observed in combination than TAM alone in both cell lines. Secondly, TAM-CXB regulated VEGFR2 inhibits Src expression, responsible for tumor progression and metastasis. FACS and in vivo enzymatic studies showed significant increase in the reactive oxygen species upon TAM-CXB treatment.

CONCLUSIONS

Taken together, our experimental results indicate that this additive combination shows promising outcome in anti-metastatic and apoptotic studies. In a line, our preclinical studies evidenced that this additive combination of TAM and CXB is a potential drug candidate for treatment of breast tumors expressing high levels of VEGF and VEGFR2. This ingenious combination might be a better tailored clinical regimen than TAM alone for breast cancer treatment.

Randomized controlled trial of toremifene 120 mg compared with exemestane 25 mg after prior treatment with a non-steroidal aromatase inhibitor in postmenopausal women with hormone receptor-positive metastatic breast cancer

BACKGROUND

After the failure of a non-steroidal aromatase inhibitor (nsAI) for postmenopausal patients with metastatic breast cancer (mBC), it is unclear which of various kinds of endocrine therapy is the most appropriate. A randomized controlled trial was performed to compare the efficacy and safety of daily toremifene 120 mg (TOR120), a selective estrogen receptor modulator, and exemestane 25 mg (EXE), a steroidal aromatase inhibitor. The primary end point was the clinical benefit rate (CBR). The secondary end points were objective response rate (ORR), progression-free survival (PFS), overall survival (OS) and toxicity.

METHODS

Initially, a total of 91 women was registered in the study and randomly assigned to either TOR120 (n = 46) or EXE (n = 45) from October 2008 to November 2011. Three of the 46 patients in the TOR120 arm were not received treatment, 2 patients having withdrawn from the trial by their preference and one having been dropped due to administration of another SERM.

RESULTS

When analyzed after a median observation period of 16.9 months, the intention-to-treat analysis showed that there were no statistical difference between TOR120 (N = 46) and EXE (n = 45) in terms of CBR (41.3% vs. 26.7%; P = 0.14), ORR (10.8% vs. 2.2%; P = 0.083), and OS (Hazard ratio, 0.60; P = 0.22). The PFS of TOR120 was longer than that of EXE, the difference being statistically significant (Hazard ratio, 0.61, P = 0.045). The results in treatment-received cohort (N = 88) were similar to those in ITT cohort. Both treatments were well-tolerated with no severe adverse events, although the treatment of 3 of 43 women administered TOR120 was stopped after a few days because of nausea, general fatigue, hot flush and night sweating.

CONCLUSIONS

TOR120, as a subsequent endocrine therapy for mBC patients who failed non-steroidal AI treatment, could potentially be more beneficial than EXE.

TRIAL REGISTRATION NUMBER

UMIN000001841.

Biomarkers for anti-angiogenic therapy in cancer

Angiogenesis, the development of new vessels from existing vasculature, plays a central role in tumor growth, survival, and progression. On the molecular level it is controlled by a number of pro- and anti-angiogenic cytokines, among which the vascular endothelial growth factors (VEGFs), together with their related VEGF-receptors, have an exceptional position. Therefore, the blockade of VEGF signaling in order to inhibit angiogenesis was deemed an attractive approach for cancer therapy and drugs interfering with the VEGF-ligands, the VEGF receptors, and the intracellular VEGF-mediated signal transduction were developed. Although promising in pre-clinical trials, VEGF-inhibition proved to be problematic in the clinical context. One major drawback was the generally high variability in patient response to anti-angiogenic drugs and the rapid development of therapy resistance, so that, in total, only moderate effects on progression-free and overall survival were observed. Biomarkers predicting the response to VEGF-inhibition might attenuate this problem and help to further individualize drug and dosage determination. Although up to now no definitive biomarker has been identified for this purpose, several candidates are currently under investigation. This review aims to give an overview of the recent developments in this field, focusing on the most prevalent tumor species.

Low ERK phosphorylation in cancer-associated fibroblasts is associated with tamoxifen resistance in pre-menopausal breast cancer

Purpose

The aim of this study was to evaluate ERK phosphorylation as a stromal biomarker for breast cancer prognosis and tamoxifen treatment prediction within a randomized tamoxifen trial.

Patients and Methods

Tissue microarrays of two breast cancer cohorts including in total 743 invasive breast cancer samples were analyzed for ERK phosphorylation (pERK) and smooth muscle actin-alpha expression (SMAα) in cancer-associated fibroblasts (CAFs) and links to clinico-pathological data and treatment-predictive values were delineated.

Results

By analyzing a unique randomized tamoxifen trial including breast cancer patients receiving no adjuvant treatment we show for the first time that patients low in ERK phosphorylation in CAFs did not respond to tamoxifen treatment despite having estrogen-receptor alpha (ERα-positive tumors compared to patients with high pERK levels in CAFs (P = 0.015, multivariate Cox regression interaction analysis). In both clinical materials we further show a significant association between pERK and SMAα, a characteristic marker for activated fibroblasts. SMAα expression however was not linked to treatment-predictive information but instead had prognostic qualities.

Conclusion

The data suggests that the presence of a subpopulation of CAFs, defined by minimal activated ERK signaling, is linked to an impaired tamoxifen response. Thus, this report illustrates the importance of the stroma for monitoring treatment effects in pre-menopausal breast cancer.

High-dose toremifene as first-line treatment of metastatic breast cancer resistant to adjuvant aromatase inhibitor: A multicenter phase II study

There is currently no standardized therapy available for metastatic breast cancer in patients with aromatase inhibitor (AI)-resistant breast cancer. We conducted a prospective study to examine the efficacy and safety of high-dose toremifene (TOR) treatment for the first-line treatment of metastatic breast cancer following AI adjuvant therapy. A multicenter phase II study was designed (Registry no.: UMIN000000489). Inclusion criteria comprised hormone-responsive postmenopausal women who had received adjuvant AI postoperatively for >1 year and had relapsed during the treatment or within 12 months of completion of adjuvant therapy. Treatment comprised oral intake of 120 mg TOR once a day. The primary endpoint was objective response rate (ORR). The secondary endpoints were evaluations of clinical benefit (CB), progression-free survival (PFS) and toxicity. A total of 13 patients were enrolled. ORR was 7.7% (1/13) [95% CI, 0.2-36.0%]. In total, 7 patients (53.8%) had stable disease (SD), 5 of whom were long SD, and 5 patients (38.5%) experienced progressive disease (PD). The CB rate was 46.2% (6/13) [95% CI, 19.2-74.9%]. The median time to PFS was 5.9 months. No serious adverse events were observed. Patients with HER2-positive disease exhibited marginally poorer PFS (p=0.08). Patients with PD had a relatively short duration of AI treatment in contrast to responders, who had a longer period of AI treatment (p=0.02). High-dose TOR as a first-line treatment following AI adjuvant therapy was effective and well tolerated. A longer duration of adjuvant AI therapy and negative HER2 overexpression may, with further studies, be beneficial as positive predictive factors for the effectiveness of TOR treatment.

Long pentraxin-3 inhibits FGF8b-dependent angiogenesis and growth of steroid hormone-regulated tumors

Fibroblast growth factor-8b (FGF8b) exerts nonredundant autocrine/paracrine functions in steroid hormone-regulated tumors. Previous observations had shown that the soluble pattern recognition receptor long pentraxin-3 (PTX3) is a natural selective antagonist for a restricted number of FGF family members, inhibiting FGF2 but not FGF1 and FGF4 activity. Here, we assessed the capacity of PTX3 to antagonize FGF8b and to inhibit the vascularization and growth of steroid hormone-regulated tumors. Surface plasmon resonance analysis shows that PTX3 binds FGF8b with high affinity (K(d) = 30-90 nmol/L). As a consequence, PTX3 prevents the binding of FGF8b to its receptors, inhibits FGF8b-driven ERK1/2 activation, cell proliferation, and chemotaxis in endothelial cells, and suppresses FGF8b-induced neovascularization in vivo. Also, PTX3 inhibits dihydrotestosterone (DHT)- and FGF8b-driven proliferation of androgen-regulated Shionogi 115 (S115) mouse breast tumor cells. Furthermore, DHT-treated, PTX3 overexpressing hPTX3_S115 cell transfectants show a reduced proliferation rate in vitro and a limited angiogenic activity in the chick embryo chorioallantoic membrane and murine s.c. Matrigel plug assays. Accordingly, hPTX3_S115 cells show a dramatic decrease of their tumorigenic activity when grafted in immunodeficient male mice. These results identify PTX3 as a novel FGF8b antagonist endowed with antiangiogenic and antineoplastic activity with possible implications for the therapy of hormonal tumors.

The combination of VEGF inhibitors and anti-oestrogen therapies in breast cancer

Despite effective treatments for oestrogen receptor-positive breast cancers, drug resistance is common and remains a significant clinical challenge. Targeting tumour vasculature by blockade of the vascular endothelial growth factor (VEGF) has proved successful in a variety of cancers. Phase III clinical trials of bevacizumab in combination with chemotherapy showed some efficacy in breast cancer. Concomitant targeting of the VEGF and oestrogen signalling pathways has the potential to provide enhanced therapeutic benefit in oestrogen receptor-positive breast cancer, and this strategy is under evaluation in clinical trials. This article summarises the rationale for this approach and clinical studies so far.

Effects of androgen on the expression of vascular endothelial growth factor in the penile corpus cavernosum

OBJECTIVES

To investigate the effect of orchiectomy and androgen replacement on the expression of vascular endothelial growth factor (VEGF) in rat penile tissue.

MATERIAL AND METHODS

Adult male Sprague-Dawley rats (12 weeks old) were left intact (control) or surgically castrated. Orchiectomized rats were left untreated or received testosterone propionate (TP) for 7 days, beginning 1 or 2 weeks after castration. Erectile function was assessed by measuring intracavernosal pressure in response to cavernous nerve stimulation, and the expression of VEGF protein and mRNA was determined by immunohistochemistry, Western blot analysis, and reverse transcriptase-polymerase chain reaction. Serum testosterone values were measured in each animal by radioimmunoassay.

RESULTS

Serum androgen levels decreased significantly in castrated animals, whereas TP injection normalized the serum levels of testosterone. Intracavernosal pressure was significantly decreased in untreated castrated rats (31.3 ± 15.7% at 2 weeks postcastration; 18.6 ± 4.6% at 3 weeks postcastration) compared with intact controls (58.0 ± 11.4% and 58.9 ± 8.2%, respectively). Erectile function was normalized in androgen-replaced rats, irrespective of treatment was initiation 1 or 2 weeks after orchiectomy. The expression of VEGF protein and mRNA was decreased in the corpus cavernosum of castrated animals compared with controls, whereas androgen replacement normalized the expression of VEGF. These results were consistently observed by all 3 methods of assessment.

CONCLUSIONS

These data suggest that androgen regulates the expression of VEGF in rat penile corpus cavernosum and confirms the importance of androgens in the maintenance of erectile function.

Fast growth associated with aberrant vasculature and hypoxia in fibroblast growth factor 8b (FGF8b) over-expressing PC-3 prostate tumour xenografts

BACKGROUND

Prostate tumours are commonly poorly oxygenated which is associated with tumour progression and development of resistance to chemotherapeutic drugs and radiotherapy. Fibroblast growth factor 8b (FGF8b) is a mitogenic and angiogenic factor, which is expressed at an increased level in human prostate tumours and is associated with a poor prognosis. We studied the effect of FGF8b on tumour oxygenation and growth parameters in xenografts in comparison with vascular endothelial growth factor (VEGF)-expressing xenografts, representing another fast growing and angiogenic tumour model.

METHODS

Subcutaneous tumours of PC-3 cells transfected with FGF8b, VEGF or empty (mock) vectors were produced and studied for vascularity, cell proliferation, glucose metabolism and oxygenation. Tumours were evaluated by immunohistochemistry (IHC), flow cytometry, use of radiolabelled markers of energy metabolism ([18F]FDG) and hypoxia ([18F]EF5), and intratumoral polarographic measurements of pO2.

RESULTS

Both FGF8b and VEGF tumours grew rapidly in nude mice and showed highly vascularised morphology. Perfusion studies, pO2 measurements, [18F]EF5 and [18F]FDG uptake as well as IHC staining for glucose transport protein (GLUT1) and hypoxia inducible factor (HIF) 1 showed that VEGF xenografts were well-perfused and oxygenised, as expected, whereas FGF8b tumours were as hypoxic as mock tumours. These results suggest that FGF8b-induced tumour capillaries are defective. Nevertheless, the growth rate of hypoxic FGF8b tumours was highly increased, as that of well-oxygenised VEGF tumours, when compared with hypoxic mock tumour controls.

CONCLUSION

FGF8b is able to induce fast growth in strongly hypoxic tumour microenvironment whereas VEGF-stimulated growth advantage is associated with improved perfusion and oxygenation of prostate tumour xenografts.

SU11248, a selective tyrosine kinases inhibitor suppresses breast tumor angiogenesis and growth via targeting both tumor vasculature and breast cancer cells

SU11248 is a selective inhibitor of certain protein kinases including VEGFR types 1-3 that are expressed in human breast cancer. The present study determines whether the anti-tumor activity of SU11248 results from the inhibition of angiogenesis, as well as direct anti-proliferation and anti-migration effects on breast tumors. Eight-wk old female mice (C57BL/6) were given SU11248 at 20-40 mg/kg/d in drinking (distilled) water for 4 wks. Control mice received drinking water only. In the 2nd wk, 10(6) E0771 (mouse breast cancer) cells were injected in the left fourth mammary gland. Tumor size was monitored using dial calipers. At the end, tumors were isolated for measuring tumor size and intratumoral microvessel density (IMD) using CD31 immunohistochemistry. SU11248 significantly reduced tumor weight over the control (1.22 ± 0.28 vs. 3.28 ± 0.31 g; n = 8; p < 0.01) and IMD (111 ± 10 vs. 155 ± 6 IM#/mm2; p < 0.01). RT-PCR indicated that VEGFR1 and R2 were expressed in cultured E0771 cells. VEGF (10 ng/ml) caused a 42% increase in proliferation of E0771 cells, compared to the control (p < 0.01; n = 8), and there was a significant decrease in proliferation of E0771 cells treated with VEGF plus SU11248 (10 μmol/L) vs. the control (65%, p < 0.01). VEGF caused a 2-fold increase in the proliferation of HUVEC vs. the control (p < 0.01; n = 8), but its action was completely eradicated by SU11248. Neither VEGF nor SU11248 had any effect on the proliferation of cultured HAS MC. Migration assay showed that SU11248 (10 μmol/L) significantly inhibited the migration of cultured E0771 cells. SU11248 significantly inhibited the proliferation of MCF-7 and MDAMB-231 cells in a dose-related manner. These findings support the hypothesis that the antitumor activity of SU11248 on breast cancer is possibly mediated by targeting the paracrine and autocrine effects of VEGF on breast cancer to suppress tumor angiogenesis, proliferation and migration.

Antiangiogenic strategies in breast cancer management

Angiogenesis is considered one of the key mechanisms of tumour growth and survival. Therefore it represents an ideal pharmaceutical target. Many antiangiogenic agents have been developed so far in several solid tumours and also in breast cancer. Vascular endothelial growth factor (VEFG) is the main target and both monoclonal antibodies and small molecules belonging to the tyrosine kinase inhibitors directed against VEGF(R) have been developed. Some other therapeutic approaches have shown to exert some antiangiogenic activity, such as hormonal agents, metronomic chemotherapy, bisphosphonates and others. In this paper we provide an introduction of the current data supporting the angiogenesis in breast cancer and a review of the most relevant antiagiogenic therapies which have been investigated so far.

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.

Roles of small RNAs in tumor formation

MicroRNAs (miRNAs) are small noncoding RNAs that act as post-transcriptional repressors of gene expression in organisms ranging from plants to humans. A widespread role for miRNAs in diverse molecular processes driving the initiation and progression of various tumor types has recently been described. Here, we discuss the etiology of the aberrant expression of miRNAs in human cancers and their role in tumor metastasis, which might define miRNAs as oncogenes or tumor suppressors. Moreover, we highlight the genomic/epigenetic alterations and transcriptional/post-transcriptional mechanisms associated with the misexpression of miRNAs in cancer. A better understanding of miRNA biology might ultimately yield further insight into the molecular mechanisms of tumorigenesis and new therapeutic strategies against cancer.

Prolonged tamoxifen treatment increases relapse-free survival for patients with primary breast cancer expressing high levels of VEGF

Previous retrospective studies have shown that high intratumoural levels of vascular endothelial growth factor (VEGF) correlate with an inferior outcome for patients treated with adjuvant tamoxifen. Our objectives were to validate the impact of VEGF on survival after adjuvant tamoxifen and to investigate the interaction between VEGF and treatment duration. For this purpose tumour homogenates from 402 patients with operable oestrogen receptor positive breast cancer (BC), treated with tamoxifen for 2 (n=149) or 5 years (n=253) as the only systemic adjuvant therapy were included. The median follow-up time for surviving patients was 9.8 years (range 0.5-14.8 years). Expression of VEGF was assessed by an enzyme-linked immunosorbent assay and investigated in relation to the standard BC parameters and survival. In the total population, higher VEGF was significantly correlated with shorter recurrence-free survival (RFS) (HR=1.63, 95%CI=1.11-2.39, p=0.010), breast cancer corrected survival (BCCS) (HR=1.82, 95%CI=1.13-2.93, p=0.014) and overall survival (OS) (HR=1.51, 95%CI=1.11-2.05, p=0.009). High VEGF was significantly associated with reduced RFS (HR=2.61, 95%CI=1.45-4.70, p=0.001) after two years of tamoxifen, whilst no difference was seen in patients treated for five years (HR=1.09, 95%CI=0.64-1.84, p=0.760). A statistically significant interaction was observed between high VEGF expression and improved RFS after 5-year tamoxifen (p=0.034). In concordance with previous studies, high VEGF was significantly correlated with shorter survival. We present data not reported previously revealing that patients expressing high levels of VEGF display a better outcome provided that tamoxifen is given for five years. Further studies on the impact of VEGF on a 5-year regimen are motivated.

Production of vascular endothelial growth factors from human lung macrophages induced by group IIA and group X secreted phospholipases A2

Angiogenesis and lymphangiogenesis mediated by vascular endothelial growth factors (VEGFs) are main features of chronic inflammation and tumors. Secreted phospholipases A(2) (sPLA(2)s) are overexpressed in inflammatory lung diseases and cancer and they activate inflammatory cells by enzymatic and receptor-mediated mechanisms. We investigated the effect of sPLA(2)s on the production of VEGFs from human macrophages purified from the lung tissue of patients undergoing thoracic surgery. Primary macrophages express VEGF-A, VEGF-B, VEGF-C, and VEGF-D at both mRNA and protein level. Two human sPLA(2)s (group IIA and group X) induced the expression and release of VEGF-A and VEGF-C from macrophages. Enzymatically-inactive sPLA(2)s were as effective as the active enzymes in inducing VEGF production. Me-Indoxam and RO092906A, two compounds that block receptor-mediated effects of sPLA(2)s, inhibited group X-induced release of VEGF-A. Inhibition of the MAPK p38 by SB203580 also reduced sPLA(2)-induced release of VEGF-A. Supernatants of group X-activated macrophages induced an angiogenic response in chorioallantoic membranes that was inhibited by Me-Indoxam. Stimulation of macrophages with group X sPLA(2) in the presence of adenosine analogs induced a synergistic increase of VEGF-A release and inhibited TNF-alpha production through a cooperation between A(2A) and A(3) receptors. These results demonstrate that sPLA(2)s induce production of VEGF-A and VEGF-C in human macrophages by a receptor-mediated mechanism independent from sPLA(2) catalytic activity. Thus, sPLA(2)s may play an important role in inflammatory and/or neoplastic angiogenesis and lymphangiogenesis.

Bevacizumab and breast cancer: current therapeutic progress and future perspectives

Bevacizumab is a humanized monoclonal antibody to VEGF, and the incorporation of bevacizumab to chemotherapy is one of the rapidly evolving areas in the treatment of breast cancer. Bevacizumab in combination with chemotherapy versus chemotherapy alone improves progression-free survival and increases the response rate in first-line therapy for locally recurrent or metastatic breast cancer. This approach has been and is still being evaluated for early breast cancer in neoadjuvant and adjuvant settings. Bevacizumab is well tolerated and has an established tolerability profile. Both tumor- and host-related biomarkers of bevacizumab activity, response and benefit are emerging from Phase I, II and III clinical trials. The biomarkers of benefit will ultimately help identify the subgroups of patients who specifically benefit from anti-VEGF therapy with bevacizumab.

Hormonal Repression of miRNA Biosynthesis Through a Nuclear Steroid Hormone Receptor

The maturation of primary microrRNAs (pri-miRNAs) to precursor miRNAs (pre-miRNAs) is mediated by the "microprocessor" complex minimally comprimising two core components, Drosha and DGCR8. However, the roles of RNA-binding proteins associated with these core units in the large Drosha complex remain to be defined. While signal-dependent regulation of miRNA biogenesis is assumed, such regulation remains to be described. here, we provide a short review based on our recent findings of hormonally-regulated pri-miRNA processing by nuclear estrogen receptor.

Inhibition of oxygen-induced hypoxia-inducible factor-1alpha degradation unmasks estradiol induction of vascular endothelial growth factor expression in ECC-1 cancer cells in vitro

Estradiol (E(2)) rapidly and strongly induces vascular endothelial growth factor (VEGF) transcription in uterine endometrial epithelial cells in vivo. We have shown that this is mediated by both the estrogen receptor-alpha and hypoxia-inducible factor (HIF)-1alpha. By contrast, E(2) induces little or no VEGF expression in cultured breast or endometrial cancer cells, which lack HIF-1alpha due to the abnormally high concentration of oxygen ( approximately 20%) to which they are exposed. To test the hypothesis that restoring HIF-1alpha in cultured cells would restore the ability of E(2) to induce VEGF expression, we treated human endometrial cancer cells (ECC-1) with cobalt chloride (CoCl(2);100 microm), which prevents oxygen-induced HIF-1alpha degradation. HIF-1alpha was absent in untreated ECC-1 cells but detectable by 4 h after treatment with CoCl(2) alone, as was a significant increase in VEGF mRNA. E(2) plus CoCl(2) induced detectable HIF-1alpha expression at 2 h and an even higher level than that induced by CoCl(2) alone at 4 h; this HIF-1alpha was localized in the nuclei. This was accompanied by increasing VEGF expression, with the increase at 4 h severalfold higher than that induced by CoCl(2) alone and was concurrent with recruitment of both HIF-1alpha and estrogen receptor-alpha to the VEGF promoter. These results confirm that HIF-1alpha plays an essential role in E(2)-induced expression of VEGF. Through the induction of increased microvascular permeability and the consequent exudation of plasma growth factors, VEGF in turn may play an essential role in cancer cell proliferation in vivo.

Maturation of microRNA is hormonally regulated by a nuclear receptor

Steroid hormones and their cognate nuclear receptors exert a wide spectrum of biological actions through regulation of transcriptional and posttranscriptional processes. However, the underlying molecular mechanism by which steroid hormones control posttranscriptional processes is largely unknown. We now report that estrogen receptor alpha (ERalpha) inhibits the maturation of a particular microRNA (miRNA) and thereby stabilizes the mRNA of an ERalpha target gene through the 3'UTR. Estrogen-bound ERalpha downregulated expression of a set of miRNAs in both animals and cultured cells. Activated ERalpha attenuated the processing of primary miRNAs into pre-miRNAs through estrogen-dependent association with the Drosha complex, resulting in stabilization of the transcript of an ERalpha target gene through its 3'UTR. Thus, a steroid hormone achieves posttranscriptional control by regulating the maturation of miRNA.

The Int7G24A variant of transforming growth factor-beta receptor type I is a risk factor for colorectal cancer in the male Spanish population: a case-control study

BACKGROUND

The Int7G24A variant of transforming growth factor-beta receptor type I (TGFBR1) has been shown to increase the risk for kidney, ovarian, bladder, lung and breast cancers. Its role in colorectal cancer (CRC) has not been established. The aims of this study were to assess the association of TGFBR1*Int7G24A variant with CRC occurrence, patient age, gender, tumour location and stage.

METHODS

We performed a case-control study with 504 cases of sporadic CRC; and 504 non-cancerous age, gender and ethnically matched controls. Genotyping analysis was performed using allelic discrimination assay by real time PCR.

RESULTS

The Int7G24A variant was associated with increased CRC incidence in an additive model of inheritance (P for trend = 0.005). No significant differences were found between Int7G24A genotypes and tumour location or stage. Interestingly, the association of the Int7G24A variant with CRC risk was significant in men (odds ratio 4.10 with 95% confidence intervals 1.41-11.85 for homozygous individuals; P for trend = 0.00023), but not in women. We also observed an increase in susceptibility to CRC for individuals aged less than 70 years.

CONCLUSION

Our data suggest that the Int7G24A variant represents a risk factor for CRC in the male Spanish population.