NETO2 promotes melanoma progression via activation of the Ca2+/CaMKII signaling pathway / 医学前沿

Melanoma is the most aggressive cutaneous tumor. Neuropilin and tolloid-like 2 (NETO2) is closely related to tumorigenesis. However, the functional significance of NETO2 in melanoma progression remains unclear. Herein, we found that NETO2 expression was augmented in melanoma clinical tissues and associated with poor prognosis in melanoma patients. Disrupting NETO2 expression markedly inhibited melanoma proliferation, malignant growth, migration, and invasion by downregulating the levels of calcium ions (Ca2+) and the expression of key genes involved in the calcium signaling pathway. By contrast, NETO2 overexpression had the opposite effects. Importantly, pharmacological inhibition of CaMKII/CREB activity with the CaMKII inhibitor KN93 suppressed NETO2-induced proliferation and melanoma metastasis. Overall, this study uncovered the crucial role of NETO2-mediated regulation in melanoma progression, indicating that targeting NETO2 may effectively improve melanoma treatment.

Analysis on tumor immune microenvironment and construction of a prognosis model for immune-related skin cutaneous melanoma / 中南大学学报(医学版)

OBJECTIVES@#Malignant melanoma is a highly malignant and heterogeneous skin cancer. Although immunotherapy has improved survival rates, the inhibitory effect of tumor microenvironment has weakened its efficacy. To improve survival and treatment strategies, we need to develop immune-related prognostic models. Based on the analysis of the Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and Sequence Read Archive (SRA) database, this study aims to establish an immune-related prognosis prediction model, and to evaluate the tumor immune microenvironment by risk score to guide immunotherapy.@*METHODS@#Skin cutaneous melanoma (SKCM) transcriptome sequencing data and corresponding clinical information were obtained from the TCGA database, differentially expressed genes were analyzed, and prognostic models were developed using univariate Cox regression, the LASSO method, and stepwise regression. Differentially expressed genes in prognostic models confirmed by real-time reverse transcription PCR (real-time RT-PCR) and Western blotting. Survival analysis was performed by using the Kaplan-Meier method, and the effect of the model was evaluated by time-dependent receiver operating characteristic curve as well as multivariate Cox regression, and the prognostic model was validated by 2 GEO melanoma datasets. Furthermore, correlations between risk score and immune cell infiltration, Estimation of STromal and Immune cells in MAlignant Tumor tissues using Expression data (ESTIMATE) score, immune checkpoint mRNA expression levels, tumor immune cycle, or tumor immune micro-environmental pathways were analyzed. Finally, we performed association analysis for risk score and the efficacy of immunotherapy.@*RESULTS@#We identified 4 genes that were differentially expressed in TCGA-SKCM datasets, which were mainly associated with the tumor immune microenvironment. A prognostic model was also established based on 4 genes. Among 4 genes, the mRNA and protein levels of killer cell lectin like receptor D1 (KLRD1), leukemia inhibitory factor (LIF), and cellular retinoic acid binding protein 2 (CRABP2) genes in melanoma tissues differed significantly from those in normal skin (all P<0.01). The prognostic model was a good predictor of prognosis for patients with SKCM. The patients with high-risk scores had significantly shorter overall survival than those with low-risk scores, and consistent results were achieved in the training cohort and multiple validation cohorts (P<0.001). The risk score was strongly associated with immune cell infiltration, ESTIMATE score, immune checkpoint mRNA expression levels, tumor immune cycle, and tumor immune microenvironmental pathways (P<0.001). The correlation analysis showed that patients with the high-risk scores were in an inhibitory immune microenvironment based on the prognostic model (P<0.01).@*CONCLUSIONS@#The immune-related SKCM prognostic model constructed in this study can effectively predict the prognosis of SKCM patients. Considering its close correlation to the tumor immune microenvironment, the model has some reference value for clinical immunotherapy of SKCM.

Diagnostic and prognostic significance of long noncoding RNA LINC00173 in patients with melanoma

SUMMARY OBJECTIVE: A growing volume of literature has suggested long noncoding RNAs (lncRNAs) as important players in tumor progression. In this study, we aimed to investigate the expression and prognostic value of lncRNA LINC00173 (LINC00173) in melanoma. METHODS: LINC00173 expression was measured in 163 paired cancerous and noncancerous specimen samples by real-time polymerase chain reaction. The correlations between LINC00173 expression with clinicopathological characteristics and prognosis were analyzed by chi-square test, log-rank test, and multivariate survival analysis. Receiver-operating characteristic curves were used for the assessment of the diagnostic value of LINC00173 for melanoma patients. RESULTS: The expression level of LINC00173 in melanoma specimens was distinctly higher than that in adjacent non-neoplasm specimens (p<0.01). Besides, LINC00173 was expressed more frequently in patients with advanced melanoma than in patients with early melanoma. Multivariate assays confirmed that LINC00173 expression level was an independent prognostic predictor of melanoma patients (p<0.05). CONCLUSION: Our data indicated that LINC00173 expression could serve as an unfavorable prognostic biomarker for melanoma patients.

CircularRNA_0119872 regulates the microRNA-582-3p/E2F transcription factor 3 pathway to promote the progression of malignant melanoma

OBJECTIVES: Malignant melanoma (MM) is an invasive tumor that poses a threat to patient health. Circular RNAs (circRNAs) are important regulators of MM carcinogenesis. In this study, we investigated the expression characteristics and biological functions of, and mechanism underlying, circ_0119872 expression in MM. METHODS: Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was employed to examine the circ_0119872, microRNA (miR)-582-3p, and E2F transcription factor 3 (E2F3) mRNA expression levels in MM tissues and cell lines. Western blotting was performed to quantify E2F3 protein expression. MM cells with circ_0119872 knockdown were established, and cell counting kit 8 (CCK-8) and transwell assays were utilized to examine the function of circ_0119872 and its effects on the malignant characteristics of MM cells. The MiRDB and TargetScan databases were used to predict the target genes of miR-582-3p. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was used to explore the biological functions of the target genes of miR-582-3p. Additionally, a dual-luciferase reporter gene experiment was performed to verify the targeting relationship between circ_0119872 and miR-582-3p as well as that between miR-582-3p and E2F3. RESULTS: Circ_0119872 was remarkably upregulated in MM tissues and cell lines. Circ_0119872 knockdown suppressed the cell proliferation and metastasis In addition, miR-582-3p was identified as a downstream target of circ_0119872. The target genes of miR-193a-3p are involved in melanogenesis and cancer-related signaling pathways. Mechanistically, circ_0119872 facilitated MM progression by adsorbing miR-582-3p and upregulating E2F3 expression. CONCLUSION: Circ_0119872 is an oncogenic circRNA that participates in the promotion of MM progression by regulating the miR-582-3p/E2F3 axis.

Investigação de variantes genéticas germinativas nos pacientes com critério clínico para melanoma hereditário em acompanhamento no ambulatório de melanoma familial do núcleo de câncer de pele do ACCamargo Cancer Center: associação com características clínicas / Germline genetic testing in patients with clinical criteria for hereditary melanoma from the familial melanoma outpatient clinic of the skin cancer Department of ACCamargo Cancer Center: correlation with clinical features

Introdução: Cerca de 5 a 10% de todos os melanomas ocorrem em famílias com predisposição hereditária. A Síndrome do Melanoma Familial (SMF) é síndrome de câncer hereditário que confere predisposição ao melanoma cutâneo e caracteriza-se pela presença de múltiplos casos de melanoma na família ou múltiplos casos de melanoma no mesmo indivíduo, podendo estar associada a outras neoplasias como o carcinoma de pâncreas. Os genes de alta penetrância mais conhecidos, relacionados a SMF, são CDKN2A e CDK4. Ambos atuam no controle negativo do ciclo celular. As variantes patogênicas em CDKN2A correspondem a 10% das famílias com dois casos de melanoma e a 30 a 40% das famílias com 3 ou mais casos, apresentando associação com câncer de pâncreas. Na SMF a prevalência de variante em CDK4 varia de 1 a 3%. Mais recentemente, variantes patogênicas em novos genes de alta penetrância foram identificadas contribuindo com a caracterização de diferentes vias de susceptibilidade ao melanoma, incluindo genes relacionados a diferenciação celular, resposta a dano do DNA e manutenção dos telômeros, como os genes BAP1, POT1, ACD, TERF2IP e TERT. São ainda de grande importância na determinação de risco para o melanoma cutâneo, variantes em genes de baixa a moderada penetrância relacionados a pigmentação da pele e diferenciação dos melanócitos como os genes MC1R e MITF. Objetivos: Identificar variantes germinativas em genes de alta e baixa a moderada penetrância associados a risco aumentado para melanoma em pacientes com critérios clínicos para a SMF, associando os achados às características clínicas dos pacientes. Material e Métodos: Seleção de pacientes com três ou mais melanomas (melanomas primários múltiplos ­ MPM) ou pacientes com diagnóstico de melanoma com dois ou mais casos de melanoma ou câncer de pâncreas em parentes de primeiro ou segundo graus (melanoma familial ­ MF). O DNA genômico foi isolado a partir de sangue periférico ou saliva e realizado teste genético com painel customizado incluindo os genes ACD, BAP1, CDK4, CDKN2A, POT1, TERT, TERF2IP, MC1R e MITF. Foi realizada análise dos dados clínicos dos pacientes e histopatológicos dos seus tumores além de comparação entre os diferentes grupos (MPM x MF) e comparação das frequências de variantes no gene MC1R com grupo controle. Resultados: Foram incluídos 37 pacientes com média de idade ao diagnóstico de 40,1 anos, prevalência do fenótipo de pele clara (89,2%), cabelos e olhos claros (> 50% dos casos), além de grande número de pacientes com história de queimadura solar na infância (89,2%) e múltiplos nevos (> 75% com > 50 nevos). Total de 148 melanomas primários, com predomínio do tipo extensivo superficial (85,8%), localização mais frequente no tronco (52,7%) e maior prevalência de melanomas finos (96,7%). Foram encontrados dois pacientes (5,6%) com variantes patogênicas (P) e quatro (11,1%) com variantes de significado incerto (VUS), nos genes de alta penetrância estudados. As variantes P foram detectadas nos genes CDKN2A e BAP1. Variantes no gene MC1R foram encontradas em 33 casos (89,2%) com predomínio das variantes classificadas como RHC ou alelos R ­ variantes de moderada penetrância (51,4%). As variantes RHC, assim como as variantes MC1R de risco desconhecido (chamados alelos u), foram mais frequentes em nossa coorte quando comparados ao grupo controle. Discussão: A frequência de variantes patogênicas nos genes de alta penetrância estudados foi baixa, considerando-se os critérios utilizados para seleção dos probandos e do número de melanomas nos pacientes e seus familiares. Em algumas famílias, o risco aumentado para melanoma pode estar relacionado à presença dos alelos R ou dos alelos u de MC1R, combinação de duas variantes distintas de MC1R em alguns casos, associado muitas vezes a fenótipo e comportamento de risco. Conclusão: A baixa frequência de variantes nos genes de alta penetrância e a alta prevalência de variantes de MC1R encontradas em nossa coorte mostra a importância do genótipo de MC1R na determinação do risco de melanoma nas famílias brasileiras com critérios clínicos para a Síndrome do Melanoma Familial

Introduction: Approximately 5 to 10% of all melanoma cases occur in a familial context. Familial melanoma syndrome confers hereditary predisposition to cutaneous melanoma and other malignancies such as pancreatic carcinoma. It is characterized by families with multiple melanoma cases or individuals with multiple primary melanomas. CDKN2A and CDK4 were the first and second high-penetrance melanoma gene identified, respectively, both acting in cell cycle regulation. In general, CDKN2A pathogenic variants are found in 10 % of melanoma-prone families with two melanoma cases and in 30 to 40% of families with 3 or more cases, being associated with pancreatic cancer. The prevalence of CDK4 pathogenic variants varies from 1 to 3%. More recently, pathogenic variants in new high-penetrance genes have been identified, contributing to characterization of distinct melanoma susceptibility pathways, including genes related to cellular differentiation, response to DNA damage and maintenance of telomeres, such as BAP1, POT1, ACD, TERF2IP and TERT. Variants in low- to moderate-penetrance genes related to skin pigmentation and melanocytes differentiation, such as MC1R and MITF, are also of great importance in determining risk for cutaneous melanoma. Objectives: To identify germline variants in high and low- to moderate-penetrance genes associated with increased risk for melanoma in patients with clinical criteria for familial melanoma syndrome, and to correlate the findings with clinical features of the patients. Material and Methods: Patients diagnosed with three or more melanomas (multiple primary melanomas - MPM) or melanoma patients with two or more cases of melanoma or pancreatic cancer in first or second degree relatives (familial melanoma - FM). The genomic DNA was isolated from peripheral blood or saliva and genetic testing was performed using a panel including ACD, BAP1, CDK4, CDKN2A, POT1, TERT, TERF2IP, MC1R and MITF genes. We analyzed patients' clinical features and tumors' histopathological characteristics, comparing these findings between the two groups (MPM x FM). In addition, we performed comparison of MC1R variants frequencies between the cohort and the control group. Results: Thirty seven patients were included, with a mean age at diagnosis of 40.1 years, prevalence of the fair skin phenotype (89.2%), blond/red hair and light eyes (> 50%), history of childhood sunburn (89.2%) and multiple nevi (> 75% with > 50 nevi). A total of 148 primary melanomas were identified with a predominance of superficial spreading histological subtype (85.8%), location on the trunk (52.7%) and thin melanomas (96.7%). We identified two patients (5.6%) with pathogenic (P) variants and four patients (11.1%) with variants of uncertain significance (VUS) n the high-penetrance genes studied. The P variants were detected in CDKN2A and BAP1 genes. MC1R variants were found in 33 cases (89.2%) with a predominance of RHC variants or R alleles ­ moderate-penetrance variants (51.4%). The RHC variants as well as the unknown risk variants (the so-called u alleles) were more frequent in our cohort when compared to the control group. Discussion: The frequency of pathogenic variants in the high-penetrance genes studied was low, considering the proband selection criteria and the number of melanomas found in the patients and their families. In some families, the increased risk for melanoma may be related to the presence of the R alleles or the u alleles of MC1R, a combination of two distinct MC1R variants in some cases, both conditions often associated with phenotype and behavior of risk. Conclusion: The low frequency of pathogenic variants in the high-penetrance genes and the high prevalence of MC1R variants found in our cohort show the importance of MC1R genotype in determining the risk of melanoma in the Brazilian melanoma-prone families

MicroRNA-107 is a novel tumor suppressor targeting POU3F2 in melanoma

BACKGROUND: Melanoma is one of the major types of skin cancer. The metastatic melanoma is among the most lethal forms of malignant skin tumors. We hereby aimed to characterize a novel microRNA (miR) in the metastatic melanoma model. METHODS: First, we evaluated the expression of miR-107 in melanoma cells and tumor tissues. The comparison between primary and metastatic cancer tissues was also accessed. Next, we examined the impact of miR-107 on melanoma cell proliferation, cell cycle, colony formation, apoptotic activity, migration and matrix invasion. A downstream target of miR-107 was also predicted and validated functionally in melanoma cells. RESULTS: Our findings showed miR-107 was significantly downregulated in melanoma. Its expression was lowest in metastatic form. Over-expression of miR-107 reduced melanoma cell proliferation, migration and invasion. POU3F2 was identified as the downstream target of miR-107. Over-expression of POU3F2 antagonized miR-107-mediated inhibitory effect on melanoma cells. CONCLUSION: Our study has reported miR-107 as a novel tumor suppressive factor in the metastatic melanoma model. It has provided new avenue to manage melanoma and improve the survival rate in the advanced stage.

Estado mutacional de BRAF y parámetros histopatológicos en melanoma maligno cutáneo / Mutational status of BRAF and histopathological characteristics in cutaneous malignant melanoma

El melanoma maligno es la forma más agresiva de cáncer de piel, con una tasa de mortalidad en Argentina 1997-2001 = 1.1/100 000 en varones y 0.6 en mujeres. El proto-oncogén BRAF es foco de intensa investigación, su mutación es uno de los principales promotores tumorales y pueden presentarse en 50% de los melanomas. Se han aprobado varios fármacos con actividad clínica sobre las mutaciones BRAF. El objetivo del trabajo es evaluar el estado mutacional de BRAF (exón 15) en biopsias con melanoma maligno cutáneo y su relación con las características histopatológicas. Realizamos un estudio observacional, retrospectivo, de muestras fijadas en formol e incluidas en parafina. Revisamos edad, sexo, diagnóstico y datos histopatológicos, tamaño y porcentaje tumoral, viabilidad para análisis molecular y presencia de melanina. Evaluamos mutaciones de BRAF con PCR/secuenciación Sanger. Utilizamos test de Student, Chi cuadrado, Wilcoxon y prueba exacta de Fisher. De 49 casos se pudo purificar y secuenciar el 76% (38/49), 13/38 (34%) mujeres y 25/38 (66%) varones, edad mediana 70 años. Localización más frecuente: tórax con 14/35 (40%). Tipo histológico: extensivo superficial 18/38 (47%). Niveles de Clark, 11/38 (29%): I-II y 27/38 (71%): III, IV y V. Mediana del Breslow: 1.6 mm. Fase de crecimiento radial 11/38 (29%) y 27/38 (71%) vertical. Presentaron mutaciones 16/38 (42%). Como lo informado por otros autores, no se encontró asociación entre el estado mutacional del exón 15 y los parámetros clínicos o histopatológicos.

Malignant melanoma (MM) is the more aggressive form of skin cancer with a mortality rate in Argentina 1997-2001 = 1.1/100 000 in men and 0.6 in women. BRAF proto-oncogene is focus of intense research; its mutation is one of the main tumor promoters and occurs in approximately 50% of MM. Several drugs with clinical activity on BRAF mutations have been approved. The aim of the study is to evaluate the mutational status of BRAF (exon 15) in cutaneous MM biopsies and its relationship with histopathological characteristics. We carried out an observational, retrospective study of samples fixed in formaldehyde and paraffin embedded; reviewing age, sex, diagnosis, histopathological data, tumor size and percentage, viability for molecular analysis and melanin presence. We evaluated BRAF mutations with PCR/Sanger sequencing. For statistics we used Student's t test, Chi square, Wilcoxon and Fisher's exact test. We were able to purify and sequence 76% (38/49) samples, 13/38 (34%) from women and 25/38 (66%) from men, the median age being 70 years. Most frequent location: thorax 14/35 (40%). Histological type: Superficial spreading 18/38 (47%). Clark´s levels, 11/38 (29%): I-II and 27/38 (71%): III, IV and V. Breslow´s median: 1.6 mm. Radial growth phase 11/38 (29%) and 27/38 (71%) vertical. Presented mutations 16/38 (42%). As reported by other authors, no association was found between the mutational state of exon 15 and clinical or histopathological parameters.

Hereditary melanoma: a five-year study of Brazilian patients in a cancer referral center - phenotypic characteristics of probands and pathological features of primary tumors

Abstract: BACKGROUND: Approximately five to 10% of all melanomas occur in families with hereditary predisposition and the main high-risk melanoma susceptibility gene is the CDKN2A. OBJECTIVES: To describe, after a five-years study, the clinical data of patients (probands) from familial melanoma kindreds, and the pathological characteristics of their melanoma. METHODS: The inclusion criteria were melanoma patients with a family history of melanoma or pancreatic cancer (first- or second-degree relatives) or patients with multiple primary melanomas (MPM). RESULTS: A total of 124 probands were studied, where 64 were considered familial cases and 60 MPM. Mean age at diagnosis was 50 years. Our results show that the following characteristics were prevalent: skin phototype I/II (89.5%), sunburn during childhood (85.5%), total number of nevi ≥50 (56.5%), Breslow thickness ≤1.0mm (70.2%), tumors located on the trunk (53.2%) and superficial spreading melanomas (70.2%). STUDY LIMITATIONS: Analyses of probands' relatives will be demonstrated in future publication. CONCLUSIONS: Our findings are in agreement with previous familial melanomas reports. Fifteen new melanomas in 11 patients were diagnosed during follow up, all of which were ≤1.0 mm. This is the largest dataset of Brazilian melanoma prone kindreds to date, thus providing a complete database for future genetic studies.

Genética molecular del melanoma lentiginoso acral / Molecular genetics of acral lentiginous melanoma

En la última década se ha avanzado en la caracterización genética y mapeo molecular del melanoma cutáneo con el objetivo de identificar y comprender mejor los mecanismos patogénicos propios de cada subgrupo y así desarrollar tratamientos específicos. El melanoma lentiginoso acral (MLA) constituye un subtipo de melanoma con características clínicas, epidemiológicas, histopatológicas, pronósticas y terapéuticas distintivas y su perfil mutacional no es la excepción. A diferencia del melanoma ubicado en zonas fotoexpuestas, el MLA presenta una baja tasa de mutaciones BRAF (15%) y mayor frecuencia de amplificaciones y ganancias genéticas de KIT (15-30%), CCND1 (15-40%) y TERT (20%). En esta revisión se describen las características más relevantes del MLA con énfasis en el rol que cumplen los principales genes que participan en la patogenia del MLA.

Over the last decade, the genetic characterization and molecular mapping of cutaneous melanoma has been developed in order to identify and better understand the pathogenic mechanisms of each subgroup and to develop specific treatments. Acral lentiginous melanoma (ALM) is a melanoma subtype with distinctive clinical, epidemiological, histopathological, prognostic and therapeutic features and its mutational profile is not an exception. Unlike melanoma located in photoexposed areas, MLA has a low rate of BRAF mutations (15%) and a higher frequency of amplifications and genetic gains at KIT (15-30%), CCND1 (15-40%) and TERT (20%). In this review we will describe the most relevant characteristics of MLA with emphasis on the role of the main genes involved in its pathogenesis.

Melanoma: tumor microenvironment and new treatments

Abstract: In the recent past years, many discoveries in the tumor microenvironment have led to changes in the management of melanoma and it is rising up hopes, specially, to those in advanced stages. FDA approved seven new drugs from 2011 to 2014. They are: Vemurafenib, Dabrafenib and Trametinib, kinases inhibitors used for patients that have BRAFV600E mutation; Ipilimumab (anti-CTLA4), Pembrolizumab (anti-PD-1) and Nivolumab (anti-PD-1), monoclonal antibodies that stimulate the immune system; and Peginterferon alfa-2b, an anti-proliferative cytokine used as adjuvant therapy. In this article, we will review the molecular bases for these new metastatic melanoma therapeutic agents cited above and also analyze new molecular discoveries in melanoma study, as Cancer-Testis antigens (CT). They are capable of induce humoral and cellular immune responses in cancer patients and because of this immunogenicity and their restrict expression in normal tissues, they are considered an ideal candidate for vaccine development against cancer. Among CT antigens, NY-ESO-1 is the best characterized in terms of expression patterns and immunogenicity. It is expressed in 20-40% of all melanomas, more in metastatic lesions than in primary ones, and it is very heterogeneous inter and intratumoral. Breslow index is associate with NY-ESO-1 expression in primary cutaneous melanomas, but its relation to patient survival remains controversial.

In vivo antitumor potential of extracts from different parts of Bauhinia variegata linn. Against b16f10 melanoma tumour model in c57bl/6 mice

Background: Melanoma is a metastatic type of skin cancer that is difficult to treat and the majority of efforts are directed to the design of new drugs. Medicinal Plants have been the primary source of medicines since life on earth; more than 50% of existing cancer treatments is derived from plants. Bauhinia variegata is well-known medicinal plant used from the ancient era to till date for their medicinal values. Scientific literatures have not documented any evidence of the antitumour potential of Bauhinia variegata against B16F10 melanoma tumor model in C57BL mice. The present investigation was undertaken to explore the antitumour activity of Leaf, stem bark and flower extract of Bauhinia variegata against B16F10 melanoma tumour model in C57BL mice. Methods: Hydro-methanolic extract prepared from the leaf, stem bark and flower of Bauhinia variegata were assessed for their antitumor activity. The extracts at doses of 500 and 750 mg/kg b.wt. were given orally along with cyclophosphamide (chemotherapeutic drug) for 40 days for exploring antitumor activity against melanoma tumor (B16F10) in C57BL mice. Inhibition of tumor growth, increase in survival time of animal with treatment, histopathological studies and antioxidant parameter were determined. Results: The Present investigation showed significant effect of the B. variegata L. in preventing melanoma tumor by B16F10 cell line in C57BL/6 mice. As compared with the tumour control group, the remarkable results especially in the group which received B. variegata extract and cyclophosphamide together were obtained for all of the measured parameters. Dose dependent response was observed in tumor volume, inhibition rate, life span time and antioxidant parameter of extracts. Combination treatment of cyclophosphamide and B. variegata extracts showed more pronounced effect. Conclusions: These findings suggest that B. variegata hydromethanolic extract may contain bioactive compounds of potential therapeutic significance which are relatively safe from toxic effects, and can compromise the medicinal use of this plant in folk medicine (US)

Entendiendo las terapias actuales en melanoma metastásico / Understanding current therapies in metastatic melanoma

Cutaneous melanoma is a highly aggressive tumor developing from melanocytes, its incidence is increasing, and prognosis in advanced stages is daunting. New therapies have been approved during the recent years with unprecedented results, including inhibitors of MAPK/ERK pathway and immune checkpoint blockade (anti-cytotoxic T lymphocyte antigen-4 (CTLA-4) as ipilimumab, anti-programmed cell death protein 1 (PD-L1) as pembrolizumab and anti-programmed cell death protein 1 ligand (PD-L1), among many others). The aim of this paper is to review currently available metastatic melanoma therapies focusing mainly on new therapies that have demonstrated effectiveness, after several decades of little progress in the treatment of this disease.

Multiple cutaneous melanomas associated with gastric and brain metastases

Abstract The occurrence of multiple primary melanomas in a single individual is rare. Most commonly, malignant melanocytic lesions subsequent to the initial diagnosis of melanoma are secondary cutaneous metastases. We report a patient with gastrointestinal bleeding from gastric metastasis of cutaneous melanoma. During clinical evaluation and staging, we discovered a brain metastasis associated with 3 synchronous primary cutaneous melanomas. We suggest the research on the mutation in the cyclin-dependent kinase inhibitor 2A (CDKN2A) (INK4a) in such cases. We also emphasize the importance of clinical examination and dermoscopy of the entire tegument, even after a malignant melanocytic lesion is identified.

Investigação de fatores genéticos na etiologia da síndrome do melanoma familial: copy number variations (CNV) e sequenciamento de exoma / Investigation of genetic factors on the familial melanoma syndrome etiology: copy number variations (CNV) and exome sequencing

O melanoma é um tipo raro e agressivo de câncer de pele e a maioria dos casos é esporádica. Entretanto, alguns indivíduos da população apresentam alta predisposição ao desenvolvimento de tipos específicos de câncer em decorrência da presença de mutações germinativas e/ou variantes genômicas de risco. Aproximadamente 10% dos casos de melanoma cutâneo são causados por mutações germinativas, em especial no locus CDKN2A, responsável por até 40% do melanoma familial. Outros genes com mutações germinativas altamente penetrantes já foram descritos no melanoma, como CDK4, POT1, TERT, entre outros, mas tais mutações são detectadas em pouquíssimas famílias. Portanto, a etiologia genética da maior parte da predisposição ao melanoma cutâneo permanece não determinada. O objetivo central deste trabalho foi a identificação de variantes genômicas raras associadas à suscetibilidade ao melanoma cutâneo em pacientes negativos para mutações nos principais genes conhecidos. Dois tipos de abordagens metodológicas foram empregadas: o estudo de variações do número de cópias de segmentos genômicos (Copy Number Variation - CNV) e sequenciamento de exoma. A análise de CNV foi realizada em uma casuística constituída por um grupo de 41 pacientes de melanoma cutâneo não relacionados (selecionados como melanoma familial e/ou melanomas múltiplos), sem mutações nos genes de predisposição a melanoma CDKN2A, CDK4, MITF e TERT. Identificamos 10 CNVs raras não recorrentes, distribuídas em 9 dos pacientes (22% da coorte). Todas as CNVs foram validadas pela técnica de PCR quantitativo em tempo real (qPCR) e, adicionalmente, não foram detectadas em um grupo controle de 400 indivíduos. As CNVs detectadas afetam segmentos genômicos grandes (>200 Kb), compreendendo 3 deleções (2q33.3-q34, 6p24.3 e 10q22.3) e 7 duplicações (6p22.1, 10q22.3, 12p12.3, 20p12.1, 4q26-q27, 8q23.1 e 9p24.2). Dentre os genes afetados pela mudança no número de cópias, os principais genes candidatos à predisposição ao melanoma cutâneo são IDH1, ANXA11 e ANGPT1. Na segunda parte deste trabalho, um subgrupo de cinco famílias de melanoma familial, sendo 2 membros afetados de cada família e negativos para CNVs raras foram selecionados para o sequenciamento de exoma. Selecionamos apenas variantes genômicas não-sinônimas que fossem raras na população geral (frequência < 0,01%) segundo bancos de dados populacionais e que estivessem presentes nos dois afetados da família; dessa forma, foram identificadas um total de 214 variantes genômicas raras não-sinônimas em 210 genes. Dentre essas, 63 foram consideradas danosas à função proteica, segundo algoritmos de predição. Oito variantes ocasionam perda de função protéica (LoF ­ loss-of-function). Entre os 210 genes afetados, os genes MYO7A e WRN, já foram previamente associados à predisposição ao melanoma cutâneo. Adicionalmente, o grupo de genes identificados no exoma está associado a diferentes fenótipos como melanoma (ITGA3, RECK, ADAMTS4, TYMP e MCM3), pigmentação e pele (COL4A2, HPS5, MLPH, VNN2, NID2, SLIT2 e HMCN1), além de suscetibilidade a câncer em geral (ZFHX3 e CTBP2). Em conclusão, nossos dados revelaram alterações germinativas raras em pacientes de melanoma famílial e/ou melanomas múltiplos, como CNVs e mutações potencialmente patogênicas. Este estudo, portanto, identificou novos fatores genéticos de suscetibilidade ao melanoma cutâneo na população brasileira, contribuindo com vários genes candidatos a serem explorados em futuros trabalhos.

Melanoma is a rare and aggressive kind of skin cancer and sporadic on the most cases. However, some people of the population shows high predisposition to development of specific types of cancer due germline mutations and/or genomic variants of risk. Approximately 10% of all cases of melanoma are caused by germline mutations, specially affecting the CDKN2A locus, which responds up to 40% of familial melanoma cases. Other genes harboring penetrant mutations were already described in hereditary melanoma such as CDK4, POT1, TERT, among others, but these mutations are identified in few families. Therefore, the most part of genetic etiology to cutaneous melanoma predisposition remains not elucidated. The main objective of this work was to identify rare genomic variants associated to the cutaneous melanoma susceptibility in melanoma-prone patients negative for mutations at the main genes associated to this syndrome. Two kinds of methodological approaches were applied: the assess to genomic segments of copy number variations (CNV) through high resolution SNP-arrays and exome sequencing. The cohort of hereditary melanoma was composed by 41 not-related cutaneous melanoma patients, without mutations affecting genes of melanoma predisposition CDKN2A, CDK4, MITF and TERT. We identified 10 not recurrent rare CNVs in 9 patients (22% of our cohort). All CNVs were validated using the quantitative real-time PCR (qPCR) and were not detected in a control group of 400 individuals. These CNVs affected large genomic segments (>200 Kb), comprising 3 deletions (2q33.3-q34, 6p24.3 e 10q22.3) and 7 duplications (6p22.1 10q22.3 12p12.3 20p12.1, 4q26-q27, 8q23.1 e 9p24.2). From this analysis the main candidate genes were: IDH1, ANXA11 e ANGPT1. The exome sequencing was performed in a subset of 5 melanoma-prone families; 2 members affected by melanoma from each family without rare CNVs. We selected non-synonimous genomic variants following 2 main criteria: rarity on population (frequency <0.1%) and common variants between patient and their affected relative. We identified a total of 214 nonsynonimous rare genomic variants in all families affecting 210 genes, which 63 were considered damaging to protein function according to prediction algorithms and 8 leads to loss-of-function (LoF). Between the 210 affected genes, were highlighted variants affecting the MYO7A and WRN genes which were previously associated to melanoma predispodition. Additionally, the set of genes identified by exome sequencing also showed relevance once are associated to melanoma phenotypes (ITGA3, RECK, ADAMTS4, TYMP and MCM3), skin and pigmentation (COL4A2, HPS5, MLPH, VNN2, NID2, SLIT2 and HMCN1) and cancer susceptibility (ZFHX3 and CTBP2). In conclusion, our data revealed rare germline alterations in familial and/or multiple melanomas, such as CNV and potential pathogenic mutations. Therefore, this study identified new genetic factors of susceptibility to cutaneous melanoma on the Brazilian population, contributing with a set of candidate genes to be deeply explored in further studies.

Efeitos das nanocápsulas de núcleo lipídico contendo acetileugenol em melanomas: estudos in vivo e in vitro / Effects of lipid-core nanocapsules with acetyleugenol in melanomas: in vivo and in vitro studies

O melanoma é uma neoplasia de pele invasivo, com maior taxa de morte, sem tratamento efetivo. Nanocápsulas poliméricas de núcleo lipídico (LNC) tem sido empregadas com sucesso como carreadores de fármacos hidrofóbicos. Como o eugenol é um composto hidrofóbico com atividades antiproliferativas e pró-apoptóticas em células cancerosas, visamos avaliar os efeitos dos tratamentos com acetileugenol (AC), LNC ou LNC contendo acetileugenol (LNC-AC) em modelo de melanoma in vivo em camundongos C57B6, e a citotoxicidade dos mesmos em células endoteliais (HUVEC) e de melanoma (SK-Mel-28) in vitro. Os resultados obtidos mostraram que: 1) tratamentos i.p. com as LNC ou com LNC-AC (50 mg/kg, 3-10 dia de indução do tumor) induziram toxicidade sistêmica e, somente o tratamento com LNC inibiu o desenvolvimento do melanoma. O tratamento com LNC, mas não com a mistura de triglicerídeos de cadeia média, por via oral, inibiu o desenvolvimento tumoral, sem toxicidade. Adicionalmente, os tratamentos com AC, LNC ou LNC-AC não foram eficazes quando administrados em fase tardia de evolução tumoral (50 mg/kg, 7-17 dia de indução do tumor, via oral); 2) os tratamentos agudos com AC, LNC ou LNC-AC (20 mg/kg, 200 µL, e.v.) não alteraram o número de leucócitos circulantes, mas os tratamentos com LNC ou com LNC-AC reduziram o comportamento de rolling dos leucócitos em vênulas póscapilares do músculo cremaster e causaram hemólise, sendo que este último efeito também foi observado após tratamento in vitro em hemácias murinas; 3) Os estudos in vitro mostraram que as LNC e LNC-AC foram captadas pelas células HUVEC e SK-Mel-28 após 1 hora de incubação; que a incubação com LNC-AC induziu apoptose tardia e necrose com maior eficácia em SK-Mel-28 do que em HUVEC; que as incubações com LNC ou LNC-AC exerceram efeitos antiproliferativos, induzindo parada na fase G2/M do ciclo celular das duas linhagens de células avaliadas; que somente a incubação com AC ou LNC-AC inibiu a adesão ao Matrigel® com maior eficácia na linhagem SK-Mel-28 do que HUVEC; que somente a incubação com as LNC reduziram a expressão de VCAM-1 em HUVEC e que as incubações com LNC ou LNC-AC reduziram a expressão de ß3 integrina em SK-Mel- 28; que nenhum dos tratamentos alterou a migração celular das HUVEC ou SK-Mel- 28; que somente a incubação com LNC-AC reduziu os níveis de espécies reativas de oxigênio em HUVEC e SK-Mel-28; que a incubação com LNC ou LNC-AC aumentou a produção de óxido nítrico (NO) pelas duas linhagens de células avaliadas; que o tratamento com L-NAME reverteu os níveis de NO e a inibição sobre a proliferação celular induzida pela incubação com LNC ou LNC-AC e; que o tratamento de células de melanoma murino com LNC ou LNC-AC parece alterar a polarizar os neutrófilos para o fenótipo N1. Associados, os resultados obtidos mostram o tratamento oral com LNC inibe o crescimento do melanoma sem induzir efeitos tóxicos, e que este efeito benéfico pode ser dependente, pelo menos em parte, da nanoencapsulação dos triglicerídios de cadeia média e da supraestrutura da formulação, com toxicidade direta sobre as células de melanoma e possível modulação do microambiente tumoral

Melanoma is the most invasive skin cancer, with high rates of death without effective treatment. Polymeric lipid-core nanocapsules (LNC) has been successfully used as carriers of hydrophobic drugs. As eugenol is an hydrophobic compound with antiproliferative and pro-apoptotic activity in cancer cells, here we aimed to evaluate the effects of treatments with acetyleugenol (AC), LNC or LNC containing acetyleugenol (LNC-AC) in an in vivo melanoma model in C57BL6 mice and the cytotoxicity of the treatments in vitro, using endothelial (HUVEC) and melanoma (SK-Mel- 28) cells. The results obtained showed that: 1) i.p. treatments with LNC or LNCAC (50 mg/kg, 3-10 days of tumor injection) induced systemic toxicity and, only the treatment with LNC inhibited the melanoma development. Treatment with LNC, but not with mix of triglycerides of medium chain, by oral route, inhibited the tumor development, without toxicity. In addition, the treatments with AC, LNC or LNC-AC were not effective when administered in the late stage of tumor evolution (50 mg/kg, 10-20 days of tumor induction, oral route); 2) the acute treatments with AC, LNC or LNC-AC (20 mg/kg, 200 µL, intravenous route) did not altered the number of circulating leukocytes, but the treatments with LNC or LNC-AC reduced the rolling behavior of leukocytes in postcapillary venules of the cremaster muscle and induced hemolysis. The latter effect was also observed after in vitro treatment using murine erythrocytes; 3) In vitro studies showed that the LNC and LNC-AC suffered uptake by HUVEC and SK-Mel-28 cells after 1 hour of incubation; that the incubation with LNC-AC induced late apoptosis and necrosis more effectively in SK-Mel-28 than in HUVEC cells; that the incubation with LNC or LNC-AC presented antiproliferative effects, by inducing G2M arrest in cell cycle in both cells lines evaluated; that only the incubation with AC or LNC-AC inhibited the adhesion in Matrigel® with more efficaccy in SK-Mel-28 than in HUVEC cells; that only incubtion with LNC reduced the VCAM-1 expression in HUVEC and the incubation with LNC or LNC-AC reduced the ß3 integrin expression in SK-Mel-28 cells; that any treatment affected the HUVEC or SK-Mel- 28 migration; that only the incubation with LNC-AC reduced the levels of reactive species of oxygen in HUVEC and SK-Mel-28 cells; that the incubation with LNC or LNC-AC increased the nitric oxide (NO) production by both cell lines used; that the treatment with L-NAME reversed the NO levels and the inhibition on cell proliferation induced by incubation with LNC or LNC-AC and; that the in vitro treatment of murine with LNC or LNC-AC altered the neutrophil polarization to N1 phenotype. Together, results obtained show that the oral treatment with LNC inhibit the melanoma growth without any toxic effect, and that the beneficial effect could be dependent, at least in part, of nanoencapsulation of medium chain triglycerides and the supraestrucuture of the formulation, with direct toxicity on melanoma cells and possible modulation of tumor microenvironment

Effects of Ischemic Postconditioning on the Hemodynamic Parameters and Heart Nitric Oxide Levels of Hypothyroid Rats / Efeito do Pós-Condicionamento Isquêmico na Hemodinâmica e nos Níveis Cardíacos de Óxido Nítrico em Ratos com Hipotireoidismo

Background: Ischemic postconditioning (IPost) is a method of protecting the heart against ischemia-reperfusion (IR) injury. However, the effectiveness of IPost in cases of ischemic heart disease accompanied by co-morbidities such as hypothyroidism remains unclear. Objective: The aim of this study was to determine the effect of IPost on myocardial IR injury in hypothyroid male rats. Methods: Propylthiouracil in drinking water (500 mg/L) was administered to male rats for 21 days to induce hypothyroidism. The hearts from control and hypothyroid rats were perfused in a Langendorff apparatus and exposed to 30 min of global ischemia, followed by 120 min of reperfusion. IPost was induced immediately following ischemia. Results: Hypothyroidism and IPost significantly improved the left ventricular developed pressure (LVDP) and peak rates of positive and negative changes in left ventricular pressure (±dp/dt) during reperfusion in control rats (p < 0.05). However, IPost had no add-on effect on the recovery of LVDP and ±dp/dt in hypothyroid rats. Furthermore, hypothyroidism significantly decreased the basal NO metabolite (NOx) levels of the serum (72.5 ± 4.2 vs. 102.8 ± 3.7 μmol/L; p < 0.05) and heart (7.9 ± 1.6 vs. 18.8 ± 3.2 μmol/L; p < 0.05). Heart NOx concentration in the hypothyroid groups did not change after IR and IPost, whereas these were significantly (p < 0.05) higher and lower after IR and IPost, respectively, in the control groups. Conclusion: Hypothyroidism protects the heart from IR injury, which may be due to a decrease in basal nitric oxide (NO) levels in the serum and heart and a decrease in NO after IR. IPost did not decrease the NO level and did not provide further cardioprotection in the hypothyroid group. .

Fundamento: O pós-condicionamento isquêmico (PCI) é um método potente utilizado para proteger o coração contra a lesão de isquemia-reperfusão (I/R). Não está claro se o PCI é eficaz quando a doença cardíaca isquêmica é acompanhada de comorbidades, tais como hipotireoidismo. Objetivo: O objetivo deste estudo foi determinar o efeito do PCI sobre a lesão de I/R do miocárdio em ratos machos com hipotireoidismo. Métodos: O hipotireoidismo foi induzido pela administração de propiltiouracila em água potável na concentração de 500 mg/L durante 21 dias. Os corações de ratos controle e com hipotireoidismo foram perfundidos utilizando o aparelho de Langendorff e expostos a isquemia global por 30 minutos, seguido de reperfusão por 120 minutos. O PCI foi iniciado imediatamente após a isquemia. Resultados: O hipotireoidismo e PCI aumentaram significativamente a pressão ventricular esquerda desenvolvida (PVED) e as taxas máximas de variação positiva (+dp/dt) e negativa (–dp/dt) da pressão ventricular esquerda durante a reperfusão em ratos controle (p < 0,05). No entanto, o PCI não teve efeito aditivo no restabelecimento da PVED e das ±dp/dt em ratos com hipotireoidismo. Além disso, o hipotireoidismo diminuiu significativamente os níveis basais séricos (72,5 ± 4,2 vs. 102,8 ± 3,7 μmol/L; p < 0,05) e cardíacos (7,9 ± 1,6 vs. 18,8 ± 3,2 μmol/L; p < 0,05) de NOx. Os níveis cardíacos de NOx não se alteraram no grupo com hipotireoidismo após I/R e PCI mas foram significativamente maiores e menores (p < 0,05) nos grupos controle após I/R e PCI, respectivamente. Conclusão: O hipotireoidismo protegeu o coração da lesão de I/R, o que pode ser devido à diminuição dos níveis séricos e cardíacos basais de óxido nítrico (NO) e à diminuição dos níveis de NO após I/R. No entanto, o PCI não diminuiu os níveis de NO e não conferiu proteção adicional ao grupo com hipotireoidismo. .

Bap1 y neoplasias melanocíticas / Bap1 and melanocytic neoplasms

El melanoma maligno cutáneo (MMC) es un cáncer genéticamente heterogéneo, en cuya patogénesis participarían varios genes. Algunos de estos activan la vía MAP kinasa (BRAF, NRAS, KIT, NF1), mientras que otros confieren una mayor susceptibilidad a melanoma familiar, como CDKN2A, CDK4, MITF y BAP1. BAP1 (BRCA1-associated-protein 1) ha sido descrito como una proteína que se une a BRCA1 para inhibir el crecimiento celular. Actualmente se sabe que es producto de un gen supresor de tumores (denominado BAP1) y que actúa como una enzima con actividad deubiquitinasa, la cual se asocia a varios complejos de proteínas, regulando diversas vías celulares relacionadas con el ciclo celular, diferenciación y muerte celular, así como también gluconeogénesis y respuesta a daño del ADN. Tanto su actividad deubiquitinasa como su localización nuclear son relevantes para su función en la supresión de tumores.

Malignant cutaneous melanoma (MMC) is a genetically heterogeneous cancer and various genes participate in its pathogenesis. Some of these genes activate the MAP kinase pathway (BRAF, NRAS, KIT, NF1) and others are related to a higher susceptibility to familial melanoma like CDKN2A, CDK4, MITF y BAP1. BAP1 (BRCA1-associated –protein 1) has been described as a BRCA1-binding protein inhibiting cell growth. This protein is a product of a gene with tumor suppressor activity, the protein being a deubiquitinase associated to multiple protein complexes regulating various cellular pathways, including the cell cycle, differentiation and cell death, as well as gluconeogenesis and DNA damage response. Both deubiquitinase activity and location to the nucleus are relevant to its tumor suppressor function.

Determinación de la mutación BRAF V600E en melanomas de pacientes uruguayos / Determination of BRAF V600E mutation in uruguayan patientÆs melanomas

Introducción: la identificación de cambios genéticos que están en la base de la génesis del melanoma ha permitido el desarrollo de terapias dirigidas específicamente contra ellos, lo que determinó, por primera vez en la historia del tratamiento sistémico del melanoma, un incremento en la sobrevida de los pacientes con enfermedad avanzada. Los mejores resultados se han obtenido con vemurafenib, terapia dirigida con-tra BRAF y que solo es efectiva cuando existe la mutación V600E, por lo que su frecuencia en una población determina-da mide el impacto que podría tener en términos de salud.Objetivo: evaluar la frecuencia de la mutación V600E en BRAF en melanomas provenientes de pacientes uruguayos.Material y método: se tomaron 28 muestras de melanoma microdisecadas y se les realizó la investigación de la mutación V600E mediante ASO-PCR (allele specific oligonucleotide - polymerase chain reaction).Resultados: se logró amplificar el ácido desoxirribonucleico (ADN) en 27 de las 28 muestras y se detectó la mutación en21 de ellas (FR: 0,78).Discusión: trabajos previos muestran una frecuencia menor de melanomas portadores de la mutación V600E de BRAF (40%-60% en población caucásica y 25% en población asiática) a la observada en nuestro estudio. Nuestros resultados, si bien requieren confirmación mediante la inclusión de unmayor número de pacientes, podrían explicarse, al menos en parte, por diferencias en la técnica utilizada y tal vez por una proporción diferente de pacientes con melanomas asociadoscon exposición solar intermitente.

Introduction: identifying genetic changes that occur in melanoma genesis has enabled the development of therapies that are specifically geared against such changes, what resulted in an increase of patientsÆ survival for thefirst time in the history of systemic treatment of melanoma, in patients with advanced disease. The best resultshave been obtained with vemurafenib, a therapy that targets the BRAF protein and is only effective in the presence of the V600E mutation. Thus, its frequency in a certain population measures its potential impact in health figures.Objective: to evaluate the frequency of the V600E mutation in BRAF in melanomas of Uruguayan patients.Method: 28 samples of microdissected melanoma were studied and V600E mutation was tested through ASO-PCR (allele specific oligonucleotide - polymerase chain reaction).Results: we managed to amplify DNA in 27 out of the 28 samples and the mutation was identified in 21 ofthem (FR: 0.78).Discussion: previous works demonstrated a lower presence of melanomas that are carriers of the V600E mutation of BRAF (40%-60% in the Caucasian population and 25% in the Asian population) than what ourstudy revealed. Our results, in spite of the need to include a larger number of patients, could partially be due todifferences in the technique used and maybe as a consequence of a different proportion of patients with melanomas associated to the intermittent sun exposure.

Introdução: a identificação de alterações genéticas associadas a origem do melanoma permitiram desenvolver terapias orientadas especificamente contra elas, o que possibilitou, pela primeira vez na história do tratamento sistêmico do melanoma, um aumento da sobrevida dos pacientes com doença avançada. Os melhores resultados foram obtidos com vemurafenib, terapia dirigida contra BRAF e que somente é efetiva quando existe a mutação V600E; sua frequência em uma população determinada mede o impacto que poderia ter sobre asaúde dessa população.Objetivo: avaliar a frequência da mutação V600E em BRAF em melanomas provenientes de pacientesuruguaios.Material e método: foram obtidas 28 amostras microdissecadas de melanoma nas quais fez-se uma pesquisa da mutação V600E utilizando ASO-PCR (allele specific oligonucleotide - polymerase chain reaction).Resultados: foi possível amplificar o ácido desoxirribonucleico (ADN) em 27 das 28 amostras; a mutação foi detectada em 21(FR: 0,78).Discussão: trabalhos anteriores mostram uma frequência menor de melanomas portadores da mutaçãoV600E de BRAF (40%-60% na população caucásica e 25% na população asiática) à observada no nosso estudo. Nossos resultados, embora seja necessário realizarum estudo com um maior número de pacientes, poderiam ser explicados, pelo menos parcialmente, pelas diferenças na técnica utilizada e talvez por una proporção diferente de pacientes com melanomas associados com exposição solar intermitente.

Radiation up-regulates the expression of VEGF in a canine oral melanoma cell line

To evaluate radiosensitivity and the effects of radiation on the expression of vascular endothelial growth factor (VEGF) and VEGF receptors in the canine oral melanoma cell line, TLM 1, cells were irradiated with doses of 0, 2, 4, 6, 8 and 10 Gray (Gy). Survival rates were then determined by a MTT assay, while vascular endothelial growth factor receptor (VEGFR)-1 and -2 expression was measured by flow cytometry and apoptotic cell death rates were investigated using an Annexin assay. Additionally, a commercially available canine VEGF ELISA kit was used to measure VEGF. Radiosensitivity was detected in TLM 1 cells, and mitotic and apoptotic cell death was found to occur in a radiation dose dependent manner. VEGF was secreted constitutively and significant up-regulation was observed in the 8 and 10 Gy irradiated cells. In addition, a minor portion of TLM 1 cells expressed vascular endothelial growth factor receptor (VEGFR)-1 intracellularly. VEGFR-2 was detected in the cytoplasm and was down-regulated following radiation with increasing dosages. In TLM 1 cells, apoptosis plays an important role in radiation induced cell death. It has also been suggested that the significantly higher VEGF production in the 8 and 10 Gy group could lead to tumour resistance.

Mecanismos de patogénesis del melanoma maligno / Mechanisms of pathogenesis of malignant melanoma

El melanoma es una de las neoplasias malignas de la piel más agresivas y peligrosas. Tiene múltiples factores de riesgo, siendo uno de los más importantes la exposición crónica e intermitente al sol. Además, tiene un componente genético que se asocia a los casos familiares, debido principalmente a las mutaciones del gen CDKN2A; sin embargo, la mayoría de los melanomas son esporádicos. En su patogenia se describen mutaciones en la línea germinal y mutaciones somáticas, las cuales modifican la regulación del ciclo celular y permiten un crecimiento no regulado. El sistema inmunitario juega un papel muy importante en la patogénesis porque, a pesar de que este tumor tiene antígenos que son claramente reconocidos, permitiendo que el sistema inmunitario monte una respuesta, las células del melanoma logran evadir la inmunidad innata y la adaptativa, para así invadir y generar metástasis.