Immunohistochemical localization of vascular factors in tooth germ of amphibian (Cynops pyrrhogaster) / Localización inmunohistoquímica de factores vasculares en germen dentario de anfibios (Cynops pyrrhogaster)

SUMMARY: Vascular endothelial growth factor (VEGF) and its receptor, VEGFR-2, are known to regulate blood vessel endothelium growth. They play important role in human and rodents teeth development. In newt jaws, there are sequential developmental teeth germs following behind the mature teeth. We examined the immunohistochemical localization of VEGF and its receptor and showed the specific expression pattern of VEGF and VEGF receptor in Cynops pyrrhogaster sequential tooth development. The intensity of immunoreactivity for VEGF in the inner enamel epithelium was weaker than that in the outer enamel epithelium in the dentine matrix formation and mineralization stages. Finally, at the enameloid maturation and enamel-like matrix formation stage, immunoreactivity for VEGF in inner enamel epithelium was stronger than in the outer enamel epithelium. The intensity of immunoreactivity for VEGFR-2 was positive for the outer enamel epithelium throughout tooth development. The crown sides of the odontoblasts were stained especially strongly for VEGF and VEGFR-2 during the dentine matrix formation and mineralization stage of the enameloid maturation and enamel- like matrix formation stage. We postulate that the expression of VEGF in the inner enamel epithelium and odontoblast widely effects tooth development in newts, as well as in human and rodents.

RESUMEN: Se sabe que el factor de crecimiento endotelial vascular (VEGF) y su receptor, VEGFR-2, regulan el crecimiento del endotelio de los vasos sanguíneos. Desempeñan un papel importante en el desarrollo de los dientes humanos y de los roedores. En las mandíbulas de tritón, hay gérmenes dentales de desarrollo secuenciales que siguen a los dientes maduros. Examinamos la localización inmunohistoquímica de VEGF y su receptor y mostramos el patrón de expresión específico de VEGF y receptor de VEGF en el desarrollo secuencial de dientes de Cynops pyrrhogaster. La intensidad de la inmunorreactividad para VEGF en el epitelio interno del esmalte era más débil que en el epitelio externo del esmalte en las etapas de formación y mineralización de la matriz de dentina. Finalmente, en la etapa de maduración del esmalte y de formación de la matriz similar al esmalte, la inmunorreactividad para VEGF en el epitelio interno del esmalte fue más fuerte que en el epitelio externo del esmalte. La intensidad de la inmunorreactividad para VEGFR- 2 fue positiva para el epitelio externo del esmalte durante el desarrollo del diente. Los márgenes de la corona de los odontoblastos se tiñeron especialmente para VEGF y VEGFR-2 durante la etapa de formación de la matriz de dentina y mineralización de la etapa de maduración del esmalte y la etapa de formación de la matriz similar al esmalte. Postulamos que la expresión de VEGF en el epitelio interno del esmalte y odontoblastos afecta ampliamente el desarrollo de los dientes en tritones, así como en humanos y roedores.

A comprehensive analysis of the angiogenesis-related genes in glioblastoma multiforme vs. brain lower grade glioma / Uma análise abrangente dos genes relacionados à angiogênese no glioblastoma multiforme vs. glioma cerebral de baixo grau

Abstract Brain tumors are one of the most common causes of cancer-related deaths around the world. Angiogenesis is critical in high-grade malignant gliomas, such as glioblastoma multiforme. Objective: The aim of this study is to comparatively analyze the angiogenesis-related genes, namely VEGFA, VEGFB, KDR, CXCL8, CXCR1 and CXCR2 in LGG vs. GBM to identify molecular distinctions using datasets available on The Cancer Genome Atlas (TCGA). Methods: DNA sequencing and mRNA expression data for 514 brain lower grade glioma (LGG) and 592 glioblastoma multiforme (GBM) patients were acquired from The Cancer Genome Atlas (TCGA), and the genetic alterations and expression levels of the selected genes were analyzed. Results: We identified six distinct KDR mutations in the LGG patients and 18 distinct KDR mutations in the GBM patients, including missense and nonsense mutations, frame shift deletion and altered splice region. Furthermore, VEGFA and CXCL8 were significantly overexpressed within GBM patients. Conclusions: VEGFA and CXCL8 are important factors for angiogenesis, which are suggested to have significant roles during tumorigenesis. Our results provide further evidence that VEGFA and CXCL8 could induce angiogenesis and promote LGG to progress into GBM. These findings could be useful in developing novel targeted therapeutics approaches in the future.

Resumo Os tumores cerebrais são uma das causas mais comuns de mortes relacionadas ao câncer em todo o mundo. A angiogênese tem caráter crítico em gliomas malignos de alto grau, como o glioblastoma multiforme. Objetivo: O objetivo deste estudo foi analisar comparativamente os genes relacionados à angiogênese, VEGFA, VEGFB, KDR, CXCL8, CXCR1 e CXCR2 em GBG vs. GBM para identificar distinções moleculares usando conjuntos de dados disponíveis no The Cancer Genome Atlas (TCGA). Métodos: Os dados de sequenciamento de DNA e expressão de mRNA para 514 pacientes com glioma cerebral de baixo grau (GBG) e 592 pacientes com glioblastoma multiforme (GBM) foram adquiridos do TCGA e as alterações genéticas e os níveis de expressão dos genes selecionados foram analisados. Resultados: Identificamos seis mutações KDR distintas nos pacientes GBG e 18 mutações KDR distintas nos pacientes GBM, incluindo mutações missense e nonsense, exclusão de mudança de quadro e região de emenda alterada. Além disso, VEGFA e CXCL8 foram significativamente super-expressos nos pacientes com GBM. Conclusões: VEGFA e CXCL8 são fatores importantes para a angiogênese, os quais parecem ter um papel significativo durante a tumorigênese. Nossos resultados fornecem evidências adicionais de que o VEGFA e o CXCL8 podem induzir a angiogênese e promover o GBG a progredir no GBM. Esses achados podem ser úteis no desenvolvimento de novas abordagens terapêuticas direcionadas no futuro.

Is the effect of melatonin on vascular endothelial growth factor receptor-2 associated with angiogenesis in the rat ovary?

OBJECTIVES Vascular endothelial growth factor (VEGF) and its receptors play important roles in angiogenesis. Melatonin plays an important role in gonadal development; thus, its effect on the reproductive system is evident. We investigated the influence of melatonin on the expression of VEGF, vascular endothelial growth factor receptor-1 (VEGFR1) and vascular endothelial growth factor receptor-2 (VEGFR2), as well as on changes in oxidative stress markers and follicle numbers in rat ovaries. METHODS For this purpose, 45 Wistar rats were separated into the following groups: Group 1, control; Group 2, vehicle; and Group 3, melatonin. Rats in Group 3 were treated with melatonin at 50 mg/kg/day for 30 days. The effects of melatonin on the expression of VEGF, VEGFR1 and VEGFR2 were established by immunohistochemistry analysis. The effects of melatonin on antioxidant enzyme activities were demonstrated by spectrophotometric analysis. RESULTS Based on immunohistochemistry analysis, VEGFR2 was predominantly localized to theca cells in the ovary. Our data indicate that melatonin treatment can significantly increase VEGF and VEGFR1 expression in the ovary ( p <0.05). Additionally, the number of degenerated follicles significantly decreased with melatonin treatment ( p <0.05). Melatonin administration also led to significant increases in antioxidant enzyme levels in the ovary. CONCLUSION Melatonin treatment exerts protective effects on follicles against increased lipid peroxidation through modulating tissue antioxidant enzyme levels. These effects may be related to angiogenesis and antioxidant activities.

Expresión de VEGF-A y VEGFR2 en Miocardio de Pollos Tratados con Ácido Acetilsalicílico (AAS) / VEGF-A and VEGFR2 Expression in Chicken Myocardium Treated with Acetylsalicylic Acid (AAS)

RESUMEN: Los niveles de VEGF y su unión a sus receptores son etapas claves en la regulación de la angiogénesis. El ácido acetilsalicílico (AAS), ampliamente utilizado en tratamiento post infarto al miocardio ha mostrado poseer un efecto antiangiogénico en modelos tumorales. Este efecto potencialmente contraproducente requiere ser estudiado en miocardio. El objetivo del presente trabajo es cuantificar el efecto de AAS y de ácido salicílico (AS) sobre la vascularización en membrana alantocoriónica (MAC) y sobre los niveles de VEGF-A y VEGFR2 en miocardio de embriones de pollo. Para ello, treinta fetos de pollo White Leghorn fueron instilados a los 10 días de gestación con 60 µL de DMSO 0,1 % (control) o conteniendo además 0,3 µmol de AAS o AS. A las 48 horas se realizó procesamiento histológico de MAC para recuento de vasos sanguíneos y de tejido cardíaco para cuantificar VEGF-A y VEGFR2 por inmunohistoquímica. La inmunorreactividad fue cuantificada mediante Image J. Tanto AAS como AS disminuyeron la densidad microvascular de MAC. En miocardio, AAS aunque no AS, disminuyó la concentración de VEGFR2. No hubo efecto sobre VEGF-A. En nuestro modelo experimental, fetos de pollo a los 10 días de gestación también se observó el efecto inhibidor de AAS sobre la angiogénesis en MAC. La disminución de VEGFR2 en cardiomiocitos sugiere que AAS también afecta la angiogénesis en miocardio sano, modificando la disponibilidad del receptor a VEGF. Estos hallazgos nos permiten postular que AAS podría interferir con la regeneración de tejido, en situaciones como post infarto al miocardio.

SUMMARY: The VEGF levels and its binding to its receptors are key stages in the regulation of angiogenesis. Acetylsalicylic acid (ASA), widely used in post-myocardial infarction treatment, has been shown to have an anti-angiogenic effect in tumor models. This potentially counterproductive effect requires to be studied in myocardium. The aim of this study is to quantify the effect of ASA and salicylic acid (SA) on the vascularization in chick allantochorionic membrane (CAM) and on the levels of VEGF-A and VEGFR2 in myocardium of chicken embryos. Thirty White Leghorn chicken fetuses were instilled at 10 days of gestation with 60 mL of 0.1 % DMSO (control) or also containing 0.3 mmol of ASA or SA. After 48 hours, CAM histological processing was performed to count blood vessels and heart tissue to quantify VEGFA and VEGFR2 by immunohistochemistry. Immunoreactivity was quantified by Image J. Both ASA and SA decreased CAM microvascular density. In myocardium, AAS, although not SA, decreased the concentration of VEGFR2. There was no effect on VEGF-A. In our experimental model, chicken fetuses at 10 days of gestation, the inhibitory effect of ASA on angiogenesis in CAM were also observed. The decrease in VEGFR2 in cardiomyocytes suggests that ASA also affects angiogenesis in healthy myocardium, modifying the availability of the receptor to VEGF. These findings allow us to postulate that ASA could interfere with tissue regeneration, when it is required, as post myocardial infarction.

The role of KDR in intrauterine adhesions may involve the TGF-ß1/Smads signaling pathway

The aim of this study was to investigate the role of kinase-insert domain-containing receptor (KDR) in intrauterine adhesions (IUA) and its mechanism. The Case group consisted of 92 patients diagnosed with IUA, and the Control group included 86 patients with uterine septum who had normal endometrium verified with an uteroscope. In addition, 50 rats were randomly assigned into Control, Sham, Model, NC-siRNA, and KDR-siRNA groups. Rats in the Model, NC-siRNA, and KDR-siRNA groups were induced by uterine curettage and lipopolysaccharide (LPS) treatment to establish the IUA model. Then, immunohistochemistry was applied for detection of VEGF and KDR expression, HE staining was used for observation of the endometrial morphology and gland counting, Masson staining for measurement of the degree of endometrial fibrosis, and qRT-PCR and western blot for the expression of KDR, VEGF, MMP-9, as well as TGF-β1/Smads pathway-related proteins. Compared with the Control group, the mRNA and protein expressions of KDR were significantly higher in IUA endometrial tissues, and the expression of KDR was positively correlated to the severity of IUA. In addition, the injection of si-KDR increased the number of endometrial glands, reduced the area of fibrosis, inhibited mRNA and protein expression of KDR and VEGF, up-regulated the expression of MMP-9 and Smad7, and decreased the expression level of TGF-β1, p-Smad2, p-Smad3, and Smad4 in rats with IUA. Highly-expressed KDR was related to patients' severity of IUA, and silencing KDR may prevent the occurrence and development of IUA via TGF-β1/Smads signaling pathway and up-regulating the expression of MMP-9.

Fatores prognósticos de resposta à quimioterapia em tumores avançados do colo uterino: o papel da neoangiogênese / Prognostic factors for response to chemotherapy in advanced tumors of the uterine cervix: the role of neoangiogenesis

RESUMO Objetivo: analisar a expressão do Fator de Crescimento do Endotélio Vascular (VEGF), seu receptor (VEGFR-2), idade e tipo histológico de carcinomas avançados de colo uterino com relação à resposta clínica à quimioterapia neoadjuvante. Métodos: foram incluídas 40 pacientes com diagnóstico de carcinoma de colo uterino (IB2 e IVA), com biópsias prévias ao tratamento. Todas as pacientes foram submetidas à quimioterapia neoadjuvante e avaliadas quanto à resposta clínica e à expressão do VEGF. Considerou-se boa resposta clínica uma regressão tumoral total ou maior do que 50%. Resultados: em relação à resposta à quimioterapia, 18 pacientes (45%) apresentaram boa resposta e 22 (55%), má resposta. Quanto à expressão do VEGF, em 16 pacientes foi considerada positiva e em 24, negativa. Quando os casos foram analisados separadamente em relação à resposta à quimioterapia, somente a expressão positiva de VEGF foi associada à boa resposta clínica (p=0,0157). Conclusão: a expressão de VEGF mostrou ser isoladamente, um importante marcador de boa resposta ao tratamento quimioterápico neoadjuvante das pacientes com carcinoma avançado de colo uterino.

ABSTRACT Objective: to analyze the expression of Vascular Endothelial Growth Factor (VEGF), its receptor (VEGFR-2), age and histological type of advanced cervical carcinomas with respect to the clinical response to neoadjuvant chemotherapy. Methods: we studied 40 patients with cervical carcinoma (IB2 and IVA) diagnosed by biopsies prior to treatment. All patients underwent neoadjuvant chemotherapy and evaluation for clinical response and expression of VEGF. We considered a tumor regression greater than 50% as a good clinical response. Results: eighteen patients (45%) had good response to chemotherapy, and 22 (55%), poor response. VEGF expression was positive in 16 patients and negative in 24. When analyzed separately for response to chemotherapy, only the positive expression of VEGF was associated with good clinical response (p=0.0157). Conclusion: VEGF expression alone was an important marker of good response to neoadjuvant chemotherapy in patients with advanced carcinoma of the cervix.

Pioglitazone Induces Cardiomyocyte Apoptosis and Inhibits Cardiomyocyte Hypertrophy Via VEGFR-2 Signaling Pathway / Pioglitazona Induz Apoptose e Inibe Hipertrofia de Cardiomiócitos pela Via de Sinalização do VEGFR-2

Abstract Background: Pioglitazone has been widely used as an insulin-sensitizing agent for improving glycemic control in patients with type 2 diabetes mellitus. However, cardiovascular risk and protective effects of pioglitazone remain controversial. Objectives: In this study, we investigated whether pioglitazone affects cardiomyocyte apoptosis and hypertrophy by regulating the VEGFR-2 signaling pathway. Methods: Cardiomyocytes were enzymatically isolated from 1- to 3-day-old Sprague-Dawley rat ventricles. Effects of pioglitazone and the VEGFR-2-selective inhibitor apatinib on cardiomyocyte apoptotic rate was determined using flow cytometry, and hypertrophy was evaluated using [3H]-leucine incorporation. The protein expressions of unphosphorylated and phosphorylated VEGFR-2, Akt, P53, and mTOR were determined by Western-Blotting. Analysis of variance (ANOVA) was used to assess the differences between groups. Results: Pioglitazone and VEGFR-2-selective inhibitor apatinib reduced rat cardiomyocyte viability and cardiomyocyte hypertrophy induced by angiotensin II in vitro. Furthermore, in the same in vitro model, pioglitazone and apatinib significantly increased the expression of Bax and phosphorylated P53 and decreased the expression of phosphorylated VEGFR-2, Akt, and mTOR, which promote cardiomyocyte hypertrophy. Conclusions: These findings indicate that pioglitazone induces cardiomyocyte apoptosis and inhibits cardiomyocyte hypertrophy by modulating the VEGFR-2 signaling pathway.

Resumo Fundamento: A pioglitazona tem sido amplamente utilizada como droga sensibilizadora da insulina para melhorar o controle glicêmico em pacientes com diabetes mellitus tipo 2. No entanto, o risco cardiovascular bem como os efeitos protetores da pioglitazona ainda são controversos. Objetivos: Neste estudo, investigamos se os efeitos da pioglitazona sobre a apoptose e a hipertrofia de cardiomiócitos ocorrem via regulação da via de sinalização do VEGFR-2. Métodos: os cardiomiócitos foram isolados enzimaticamente dos ventrículos de ratos Sprague-Dawley de 1-3 anos de vida. Os efeitos da pioglitazona e do inibidor seletivo de VEGFR-2 apatinib sobre a taxa de apoptose dos cardiomiócitos foram avaliados por citometria de fluxo, e a hipertrofia avaliada por incorporação de leucina-[3H]. As expressões de VEGFR-2, Akt, P53, e mTOR fosforiladas e não fosforiladas foram determinadas por Western Blotting. Análise de variância (ANOVA) foi usada para avaliar diferenças entre os grupos. Resultados: a pioglitazona e o apatinib reduziram a viabilidade e a hipertrofia de cardiomiócitos induzida por angiotensina II in vitro. Além disso, no mesmo modelo in vitro, a pioglitazona e o apatinib aumentaram significativamente a expressão de Bax e P53 fosforilada, e diminuiu a expressão de VEGFR-2, Akt, e mTOR, que promove hipertrofia de cardiomiócitos. Conclusões: Esses resultados indicam que a pioglitazona induz a apoptose e inibe a hipertrofia de cardiomiócitos pela modulação da via de sinalização de VEGFR-2.

Ventilation-induced changes correlate to pulmonary vascular response and VEGF, VEGFR-1/2, and eNOS expression in the rat model of postnatal hypoxia

Neonatal asphyxia occurs due to reduction in oxygen supply to vital organs in the newborn. Rapid restoration of oxygen to the lungs after a long period of asphyxia can cause lung injury and decline of respiratory function, which result from the activity of molecules that induce vascular changes in the lung such as nitric oxide (NO) and vascular endothelial growth factors (VEGF). In this study, we evaluated the pulmonary and vascular morphometry of rats submitted to the model of neonatal asphyxia and mechanical ventilation, their expression of pulmonary VEGF, VEGF receptors (VEGFR-1/VEGFR-2), and endothelial NO synthase (eNOS). Neonate Sprague-Dawley rats (CEUA #043/2011) were divided into four groups (n=8 each): control (C), control submitted to ventilation (CV), hypoxia (H), and hypoxia submitted to ventilation (HV). The fetuses were harvested at 21.5 days of gestation. The morphometric variables measured were body weight (BW), total lung weight (TLW), left lung weight (LLW), and TLW/BW ratio. Pulmonary vascular measurements, VEGFR-1, VEGFR-2, VEGF, and eNOS immunohistochemistry were performed. The morphometric analysis showed decreased TLW and TLW/BW ratio in HV compared to C and H (P<0.005). Immunohistochemistry showed increased VEGFR-2/VEGF and decreased VEGFR-1 expression in H (P<0.05) and lower eNOS expression in H and HV. Median wall thickness was increased in H, and the expression of VEGFR-1, VEGFR-2, VEGF, and eNOS was altered, especially in neonates undergoing H and HV. These data suggested the occurrence of arteriolar wall changes mediated by NO and VEGF signaling in neonatal hypoxia.

Effects of Chronic Exercise on Endothelial Progenitor Cells and Microparticles in Professional Runners / Efeitos de Exercício Crônico Sobre Células Progenitoras Endoteliais e Micropartículas em Corredores Profissionais

Abstract Background: The effects of chronic exposure to exercise training on vascular biomarkers have been poorly explored. Objective: Our study aimed to compare the amounts of endothelial progenitor cells (EPCs), and endothelial (EMP) and platelet (PMP) microparticles between professional runners and healthy controls. Methods: Twenty-five half-marathon runners and 24 age- and gender-matched healthy controls were included in the study. EPCs (CD34+/KDR+, CD133+/KDR+, and CD34+/CD133+), EMP (CD51+) and PMP (CD42+/CD31+) were quantified by flow-cytometry. All blood samples were obtained after 12 h of fasting and the athletes were encouraged to perform their routine exercises on the day before. Results: As compared with controls, the CD34+/KDR+ EPCs (p=0.038) and CD133+/KDR+ EPCs (p=0.018) were increased, whereas CD34+/CD133+ EPCs were not different (p=0.51) in athletes. In addition, there was no difference in MPs levels between the groups. Conclusion: Chronic exposure to exercise in professional runners was associated with higher percentage of EPCs. Taking into account the similar number of MPs in athletes and controls, the study suggests a favorable effect of exercise on these vascular biomarkers.

Resumo Fundamento: Os efeitos da exposição crônica ao exercício sobre biomarcadores vasculares foram pouco estudados. Objetivo: Nosso estudo teve como objetivo comparar as quantidades de células progenitoras endoteliais (CPEs), e de micropartículas endoteliais (MPEs) e plequetárias (MPPs) de corredores profissionais com controles sadios. Métodos: Vinte e cinco corredores de meia maratona e 24 controles pareados quanto à idade e ao sexo foram incluídos no estudo. CPEs (CD34+/KDR+, CD133+/KDR+ e CD34+/CD133+), MPE (CD51+) e MPPs (CD42+/CD31+) foram quantificadas por citometria de fluxo. Todas as amostras de sangue foram obtidas após 12 horas de jejum, e os atletas foram incentivados a realizar seus exercícios de rotina no dia anterior à coleta. Resultados: Em comparação aos controles, CPEs CD34+/KDR+ (p=0,038) e CD133+/KDR+ (p=0,018) estavam aumentados, e CPEs CD34+/CD133+ não foram diferentes (p=0,51) nos atletas. As concentrações de MP não diferiram entre os grupos. Conclusão: A exposição crônica ao exercício em corredores profissionais associou-se a uma maior porcentagem de CPEs. Considerando o número similar de MPs entre atletas e controles, o estudo sugere um efeito favorável do exercício sobre esses biomarcadores vasculares.

Estrogen deficiency in ovariectomized rats: can resistance training re-establish angiogenesis in visceral adipose tissue?

OBJECTIVE: The purpose of this study was to investigate the effects of resistance training on angiogenesis markers of visceral adipose tissue in ovariectomized rats. METHOD: Adult Sprague-Dawley female rats were divided into four groups (n=6 per group): sham-sedentary, ovariectomized sedentary, sham-resistance training and ovariectomized resistance training. The rats were allowed to climb a 1.1-m vertical ladder with weights attached to their tails and the weights were progressively increased. Sessions were performed three times per week for 10 weeks. Visceral adipose tissue angiogenesis and morphology were analyzed by histology. VEGF-A mRNA and protein levels were analyzed by real-time PCR and ELISA, respectively. RESULTS: Ovariectomy resulted in higher body mass (p=0.0003), adipocyte hypertrophy (p=0.0003), decreased VEGF-A mRNA (p=0.0004) and protein levels (p=0.0009), and decreased micro-vascular density (p=0.0181) in the visceral adipose tissue of the rats. Resistance training for 10 weeks was not able to attenuate the reduced angiogenesis in the visceral adipose tissue of the ovariectomized rats. CONCLUSION: Our findings indicate that the resistance training program used in this study could not ameliorate low angiogenesis in the visceral adipose tissue of ovariectomized rats.

Caracterização funcional das isoformas variantes de 'splicing' da osteopontina nos carcinomas de ovário e próstata / Functional characterization of osteopontin 'splicing' variant isoforms in ovarian and prostate carcinomas

"A osteopontina (OPN) é um dos transcritos que apresenta maiores aumentos no nível de expressão no câncer de ovário (CO) e próstata (CaP), e está envolvida na tumorigênese e metástase. O gene que codifica a OPN está sujeito à 'splicing' alternativo, gerando 3 mensagens, denominadas de OPNa, OPNb e OPNc. O objetivo deste projeto é a caracterização do perfil de expressão e do papel funcional das isoformas variantes de 'splicing' da OPN na tumorigênese e progressão tumoral no CO e CaP. A OPNc encontra-se especificamente expressa nos tumores malignos de ovário. No CaP, observamos que as isoformas apresentam maior nível de expressão na amostras de CaP quando comparado com o tumor benigno da próstata. A expressão diferencial das isoformas da OPN nas amostras tumorais e não tumorais de ovário e próstata identificam as isoformas como potenciais novos biomarcadores para estas neoplasias. Observamos que a OPNc, no modelo de ovário e próstata, e a OPNb, no modelo de próstata, apresentam efeitos estimulatórios sobre a proliferação, migração, invasão, formação de colônia e crescimento de tumores in vivo. A OPNc nos dois modelos tumorais estimula a proliferação celular da IOSE e RWPE-1, indicando que a OPNc apresenta características pró-tumorigênicas. Descrevemos também que os efeitos da OPNb e OPNc são mediados pela via de sinalização PI3K/Akt. Com base na observação de que tumores que superexpressam a OPNc apresentam altos níveis de expressão de marcadores típicos de angiogênese nos tumores ovarianos, tais como VEGF-A, Flk-1 e CD34, investigamos o papel funcional e o mecanismo molecular pelo qual a OPNc estimula a angiogênese no CO. Nossos dados demonstram que a OPNc secretada interage com receptores do tipo integrinas de forma RGD-dependente, possivelmente ativando a via de sinalização PI3K/Akt. Observamos também que a OPNc secretada e a via de sinalização PI3k/Akt modulam a expressão de VEGF-A, c-Fos e c-Jun e a fosforilação de c-Jun. Adicionalmente, observamos que o meio condicionado da OPNc induz a proliferação, migração e adesão das células endoteliais HUVEC, de forma a contribuir para a neovascularização. Através de PCR em tempo real, caracterizamos que a OPNc altera a expressão de 34 genes, no modelo de CO, e 16 genes, no CaP, essenciais para a transformação e progressão tumoral destas neoplasias. Os resultados gerados por este estudo contribuem para o melhor entendimento da biologia e dos mecanismos moleculares do CO e CaP. O papel crucial destas isoformas em distintas etapas da progressão destes tumores indicam a OPNb e OPNc como potenciais alvos terapêuticos para o CO e CaP"(AU)

"Osteopontin (OPN) is one of the proteins overexpressed in ovarian carcinoma (OC) and prostate cancer (PCa), and is involved in tumorigenesis and metastasis. Alternative splicing of OPN (OPN-SI) leads to 3 isoforms, OPNa, OPNb, and OPNc. This study aims to characterize the expression profile and functional roles of OPN isoforms in OC and PCa tumor progression. In OC, OPNc is specifically expressed in ovarian tumor samples. PCa tissue samples presented significantly higher levels of OPN-SI transcripts than in BPH specimens. OPN-SI mRNA expression were positively correlated with Gleason Score. The OPNc isoform was the most upregulated variant and the best marker to distinguish patients groups, presenting sensitivity and specificity of 90% and 100%, respectively. OPNc, in OC and PCa, and OPNb, in PCa, significantly activated OvCar-3 and PC-3 cell proliferation, migration, invasion, anchorage independent growth and tumor formation in vivo. Additionally, we have also shown that some of the OPNc-dependent protumorigenic roles are mediated by PI3K/Akt signaling pathway. OPNc stimulated immortalized ovarian and prostate epithelial cell proliferation, indicating a role for this isoform in OC and PCa tumorigenesis. Functional assays using OPNc conditioned medium and an anti-OPNc antibody have shown that most cellular effects observed here were promoted by the secreted OPNc. We identified that OPNc can affect the expression of genes involved in cancer pathways in these tumor models. Tumors formed by OvCar-3 OPNc-overexpressing cells present high expression levels of typical angiogenesis markers, as VEGF-A, VEGFR-2 and CD34. Based on this observation, we also investigated the molecular mechanisms by which OPNc stimulates angiogenic processes. Our data showed that OPNc overexpression activates VEGF-A expression and secretion, also through the PI3K/Akt pathway. This splicing isoform is also able to activate the expression of c-Fos, c-Jun and phospho-c-Jun. OPNc role on activating the phosphorylation of c-Jun is mediated by integrin receptor, in an RGD dependent manner. OPNc-conditioned medium is able to induce HUVEC endothelial cells proliferation, migration and adhesion. According to our data, contributes to the physiopathology of ovarian and prostate cancer progression and tumorigenesis. Altogether, the data open possibilities of new therapeutic approaches that selectively down regulate OPNc, altering its properties favoring OC and PCa tumor progression"(AU)

Terapia antiangiogénica en cáncer de mama / Antiangiogenic therapy in breast cancer

La angiogénesis es el proceso de formación de vasos sanguíneos y juega un rol central en el crecimiento local y de metástasis a distancia en cáncer de mama. Normalmente existe un equilibrio entre los factores pro y antiangiogénicos. La angiogénesis es un importante paso en el desarrollo, invasión, progresión y metástasis tumoral, y es regulado principalmente por factores pro angiogénicos; entre estos factores el VEGF es el más importante. Otros factores pro angiogénicos que participan son: PDGF-BB, ECF, TNF" y bFGF.Estudios clínicos han demostrado que altos niveles de VEGF se correlacionan con un peor pronóstico y disminución de la sobrevida en pacientes con cáncer de mama. De esta manera, se postuló que VEGF es un blanco terapéutico válido. Recientemente se ha iniciado una nueva era en el tratamiento contra el cáncer que consiste en el uso de anticuerpos monoclonales y pequeñas moléculas blanco que bloquean el proceso angiogénico. Estas estrategias se desarrollaron inicialmente con la idea de inhibir el crecimiento de los nuevos vasos sanguíneos y de esta manera disminuir el oxigeno y nutrientes del tumor. Sin embargo, el beneficio asociado a la terapia anti VEGF es modesto y probablemente involucre múltiples mecanismos. Un mejor conocimiento de estos mecanismos va a permitir el avance futuro de estos agentes en la clínica.La propuesta de esta revisión es:a) examinar el rol de VEGF y la biología tumoralb) describir los efectos de la terapia antiangiogénicac) mencionar los últimos ensayos clínicos con agentes antiangiogénicos como agentes únicos y combinados con agentes citotóxicos, en el tratamiento del cáncer de mama