Avaliação da angiogênese em resposta ao tratamento com melatonina no câncer de mama: estudo in vitro e in vivo

Breast cancer has high rates of incidence and mortality, and it is the most common cancer among women. The rapid tumor growth results in hypoxia on tumor microenvironment, leading to a cascade of events that induce angiogenesis and subsequent cancer progression. Thus, the identification of therapeutic agents that can inhibit angiogenesis is essential for the control of tumor progression. Exogenous administration of melatonin, a hormone secreted by the pineal gland, has been shown several oncostatics effects on different types of cancers. The aim of this study was to evaluate the effectiveness of melatonin treatment on angiogenesis in breast cancer, in the in vitro and in vivo studies. In the in vitro study, breast cancer cell lines (MCF-7 and MDA-MB-231) were treated with melatonin under cobalt chloride (CoCl2)-induced hypoxic conditions. Cell viability was measured by MTT assay, the expression of hypoxia-inducible factor 1-alpha (HIF-1α) and vascular endothelial growth factor (VEGF-A) was assessed by real-time PCR and immunocytochemistry. Additionally, other proteins involved in angiogenesis were evaluated by the Protein Array. In the in vivo study, the MDA-MB-231 cells were implanted in athymic nude mice, which were treated with melatonin (40 mg/kg) for 21 days. The tumor was measured weekly and evaluation of angiogenesis was performed by single-photon emission computed tomography (SPECT) with Tc-99m-HYNIC-VEGF-c, which is specific for VEGF receptors (VEGFR2/VEGF3). Moreover, VEGFR2, VEGFR3, von Willebrand factor (vWF) and cell proliferation marker (Ki-67) were evaluated in tumor tissue by immunohistochemistry, and other angiogenic proteins by Protein Array. Results from the in vitro study showed that 1 mM of melatonin under hypoxic conditions (200 μM CoCl2) led to decreased cell viability, protein levels of HIF- 1α and gene and protein expression of VEGF-A in both cell lines (p < 0.05). Among other proteins evaluated, melatonin ...O câncer de mama apresenta altas taxas de incidência e mortalidade, sendo a neoplasia mais comum entre as mulheres. O rápido crescimento do tumor resulta em hipóxia no microambiente tumoral, levando a uma cascata de eventos que induzem a angiogênese e conseqüente progressão do câncer. Assim, a identificação de agentes terapêuticos que possam inibir a angiogênese é essencial para o controle da progressão tumoral. Nesse sentido, tem sido demonstrado que a administração exógena da melatonina, um hormônio naturalmente secretado pela glândula pineal, apresenta diversos efeitos oncostáticos em diferentes tipos de câncer. Assim, o objetivo desse estudo foi avaliar a efetividade do tratamento com melatonina sobre a angiogênese do câncer de mama, em estudos in vitro e in vivo. No estudo in vitro, as linhagens de câncer de mama MCF-7 e MDA-MB-231 foram tratadas com melatonina sob condições de hipóxia mimetizadas pelo Cloreto de Cobalto (CoCl2). A viabilidade celular foi verificada pelo ensaio MTT, a expressão do fator de transcrição induzido por hipóxia (HIF-1α) e do fator de crescimento endotelial vascular (VEGF-A) foi avaliada por PCR em tempo real e imunocitoquímica. Além disso, demais proteínas envolvidas na angiogênese foram avaliadas por Protein Array. No estudo in vivo, as células MDA-MB-231 foram implantadas em camundongos nude atímicos, os quais foram tratados com melatonina (40 mg/kg) por 21 dias. O tumor foi medido semanalmente e a avaliação da angiogênese foi realizada pela técnica de tomografia computadorizada por emissão de fóton único (SPECT), com o radiotraçador Tc- 99m-HYNIC-VEGF-c, agente específico para os receptores de VEGF (VEGFR2/VEGF3). Além disso, as proteínas VEGFR2, VEGFR3, fator de fator de von Willebrand (vWF) e marcador de proliferação celular (Ki-67) foram avaliados no tecido tumoral por imuno-histoquímica, e demais proteínas angiogênicas por Protein Array. O estudo in ...Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Molecular markers of angiogenesis and metastasis in lines of oral carcinoma after treatment with melatonin

Background: Oral cancer is the most common type of head and neck cancer and its high rate of mortality and morbidity is closely related to the processes of angiogenesis and tumor metastasis. The overexpression of the pro-angiogenic genes, HIF-1 alpha and VEGF, and pro-metastatic gene, ROCK-1, are associated with unfavorable prognosis in oral carcinoma. Melatonin has oncostatic, antiangiogenic and antimetastatic properties in several types of neoplasms, although its relationship with oral cancer has been little explored. This study aims to analyze the expression of the genes HIF-1 alpha, VEGF and ROCK-1 in cell lines of squamous cell carcinoma of the tongue, after treatment with melatonin.Methods: SCC9 and SCC25 cells were cultured and cell viability was assessed by MTT assay, after treatment with 100 mu M of CoCl2 to induce hypoxia and with melatonin at different concentrations. The analysis of quantitative RT-PCR and the immunocytochemical analysis were performed to verify the action of melatonin under conditions of normoxia and hypoxia, on gene and protein expression of HIF-1 alpha, VEGF and ROCK-1.Results: The MTT assay showed a decrease in cell viability in both cell lines, after the treatment with melatonin. The analysis of quantitative RT-PCR indicated an inhibition of the expression of the pro-angiogenic genes HIF-1 alpha (P < 0.001) and VEGF (P < 0.001) under hypoxic conditions, and of the pro-metastatic gene ROCK-1 (P < 0.0001) in the cell line SCC9, after treatment with 1 mM of melatonin. In the immunocytochemical analysis, there was a positive correlation with gene expression data, validating the quantitative RT-PCR results for cell line SCC9. Treatment with melatonin did not demonstrate inhibition of the expression of genes HIF-1 alpha, VEGF and ROCK-1 in line SCC25, which has different molecular characteristics and greater degree of malignancy when compared to the line SCC9.Conclusion: Melatonin affects cell viability in the SCC9 and SCC25 lines and inhibits the expression of the genes HIF-1 alpha, VEGF and ROCK-1 in SCC9 line. Additional studies may confirm the potential therapeutic effect of melatonin in some subtypes of oral carcinoma.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

RNA-Seq transcriptome analysis shows anti-tumor actions of melatonin in a breast cancer xenograft model

Melatonin is a pleiotropic anti-cancer molecule that controls cancer growth by multiple mechanisms. RNA-Seq can potentially evaluate therapeutic response and its use in xenograft tumor models can differentiate the changes that occur specifically in tumor cells or in the tumor microenvironment (TME). Melatonin actions were evaluated in a xenograft model of triple-negative breast cancer. Balb/c nude mice bearing MDA-MB-231 tumors were treated with melatonin or vehicle. RNA-Seq was performed on the Illumina HiSeq. 2500 and data were mapped against human and mouse genomes separately to differentiate species-specific expression. Differentially expressed (DE) genes were identified and Weighted Gene Co-expression Network Analysis (WGCNA) was used to detect clusters of highly coexpressed genes. Melatonin treatment reduced tumor growth (p < 0.01). 57 DE genes were identified in murine cells, which represented the TME, and were mainly involved in immune response. The WGCNA detected co-expressed genes in tumor cells and TME, which were related to the immune system among other biological processes. The upregulation of two genes (Tnfaip8l2 and Il1f6) by melatonin was validated in the TME, these genes play important roles in the immune system. Taken together, the transcriptomic data suggests that melatonin anti-tumor actions occur through modulation of TME in this xenograft tumor model9FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2014/13815-5Fundacao de Amparo a Pesquisa do Estado de Sao PauloFundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [2014/13815-5]; Fundacao de Apoio a Pesquisa e Extensao de Sao Jose do Rio Preto (FAPERP

Evaluation of melatonin treatment in primary culture of canine mammary tumors

Mammary neoplasias are the most common tumors observed in female dogs. Identification of these tumors is valuable in order to identify beneficial therapeutic agents as alternative treatments for this tumor type. Oral administration of melatonin appears to exert an oncostatic effect on mammary neoplasia and may have a possible mechanism of action through its interaction with estrogen receptors on epithelial cells. Hence, we analyzed the potential therapeutic value of melatonin in tumors that are estrogen-dependent or -independent, and established a relationship of its action with the expression of the melatonin receptors MT1 and MT2. Furthermore, we analyzed the rate of cell proliferation and apoptosis after treatment with melatonin. Cell cultures were performed using 10 canine mammary tumor fragments and were divided into estrogen receptor (ER)-positive and ER-negative tumors. The results showed that both ER-positive and ER-negative tumors had decreased cell viability and proliferation after treatment with melatonin (p<0.05), although treatment was more effective in the ER-positive tumors. Analysis of the relative expression of the MT1 and MT2 genes by quantitative PCR was performed and the data were compared with the expression of ER in 24 canine mammary tumors and the cellular response to melatonin in 10 samples. MT1 was overexpressed in ER-positive tumors (p<0.05), whereas MT2 was not expressed. Furthermore, melatonin treatment in ER-positive tumors showed an efficient oncostatic effect by inhibiting cell viability and proliferation and inducing apoptosis. These results suggest that melatonin decreased neoplastic mammary cell proliferation and viability and induced apoptosis, with greater efficacy in ER-positive tumors that have a high expression of melatonin receptor MT1. This is a strong evidence for the use of melatonin as a therapeutic agent for estrogen-dependent canine mammary tumors.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Effect of melatonin on tumor growth and angiogenesis in xenograft model of breast cancer

As neovascularization is essential for tumor growth and metastasis, controlling angiogenesis is a promising tactic in limiting cancer progression. Melatonin has been studied for their inhibitory properties on angiogenesis in cancer. We performed an in vivo study to evaluate the effects of melatonin treatment on angiogenesis in breast cancer. Cell viability was measured by MTT assay after melatonin treatment in triple-negative breast cancer cells (MDA-MB-231). After, cells were implanted in athymic nude mice and treated with melatonin or vehicle daily, administered intraperitoneally 1 hour before turning the room light off. Volume of the tumors was measured weekly with a digital caliper and at the end of treatments animals underwent single photon emission computed tomography (SPECT) with Technetium-99m tagged vascular endothelial growth factor (VEGF) C to detect in vivo angiogenesis. In addition, expression of pro-angiogenic/growth factors in the tumor extracts was evaluated by membrane antibody array and collected tumor tissues were analyzed with histochemical staining. Melatonin in vitro treatment (1 mM) decreased cell viability (p0.05) images. In addition, there was a decrease of micro-vessel density (Von Willebrand Factor) in melatonin treated mice (p<0.05). However, semiquantitative densitometry analysis of membrane array indicated increased expression of epidermal growth factor receptor and insulin-like growth factor 1 in treated tumors compared to vehicle treated tumors (p<0.05). In conclusion, melatonin treatment showed effectiveness in reducing tumor growth and cell proliferation, as well as in the inhibition of angiogenesis.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Intraperitoneal Delivery of Iopamidol to Assess Extracellular pH of Orthotopic Pancreatic Tumor Model by CEST-MRI

The extracellular pH (pHe) of solid tumors is often acidic, as a consequence of the Warburg effect, and an altered metabolic state is often associated with malignancy. It has been shown that acidosis can promote tumor progression; thus, many therapeutic strategies have been adopted against tumor metabolism; one of these involves alkalinization therapies to raise tumor pH to inhibit tumor progression, improve immune surveillance, and overcome resistance to chemotherapies. Chemical exchange saturation transfer-magnetic resonance imaging (CEST-MRI) is a noninvasive technique that can measure pH in vivo using pH-sensitive contrast agents. Iopamidol, an iodinated contrast agent, clinically used for computed tomography (CT), contains amide group protons with pH-dependent exchange rates that can reveal the pHe of the tumor microenvironment. In this study, we optimized intraperitoneal (IP) delivery of iopamidol to facilitate longitudinal assessments of orthotopic pancreatic tumor pHe by CEST-MRI. Following IV-infusion and IP-bolus injections, we compared the two protocols for assessing tumor pH. Time-resolved CT imaging was used to evaluate the uptake of iopamidol in the tumor, revealing that IP-bolus delivered a high amount of contrast agent 40 min postinjection, which was similar to the amounts reached with the IV-infusion protocol. As expected, both IP and IV injection protocols produced comparable measurements of tumor pHe, showing no statistically significant difference between groups (p=0.16). In addition, we showed the ability to conduct longitudinal monitoring of tumor pHe using CEST-MRI with the IP injection protocol, revealing a statistically significant increase in tumor pHe following bicarbonate administration (p<0.001). In conclusion, this study shows the capability to measure pHe using an IP delivery of iopamidol into orthotopic pancreatic tumors, which is important to conduct longitudinal studies

Prognostic value of vascular endothelial growth factor and hypoxia-inducible factor 1 alpha in canine malignant mammary tumors

Mammary tumors are the most common type of tumor in dogs, with approximately half of these tumors being malignant. Hypoxia, characterized by oxygen levels below normal, is a known adverse factor to cancer treatment. The hypoxia-inducible factor 1 alpha(HIP-1 alpha) is a central regulator of the pathophysiological response of mammalian cells to low oxygen levels. HIF-1 alpha activates the transcription of vascular endothelial growth factor (VEGF), which in turn promotes angiogenesis through its ability to stimulate the growth, migration and invasion of endothelial cells to form new blood vessels, contributing to tumor progression: In this study, we evaluated the serum concentration and gene expression of VEGF and HIP-1 alpha linking them with clinicopathological parameters and survival of dogs with mammary tumors in order to infer the possible prognostic value of these factors. We collected blood and tumor fragments of 24 female dogs with malignant mammary tumors (study group) and 26 non-affected female dogs (control group) to verify the gene expression of VEGF and HIF-1 alpha by quantitative real-time PCR (qPCR) and the serum levels by ELISA (enzyme-linked immunosorbent). The results showed high serum levels of VEGF in the study group and its correlation between abundant vascularization, lymph node involvement, metastasis, death rate and low survival (p&lt;0.05). The serum percentage of HIF-1 alpha in female dogs with mammary neoplasia was lower than that in the control group and higher in female dogs with tumor metastasis and history of tumor recurrence (p&lt;0.05). Regarding gene expression, there was a gene overexpression of VEGFA in female dogs with poor outcome, in contrast to the gene underexpression of HIP-1A. Taken together, these results suggested that VEGF is important in tumor progression and can be used as a potential prognostic marker in the clinic and may be useful in predicting tumor progression in dogs with mammary neoplasia.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP