Anticarcinogenic activity of methanol extract of Melastoma malabathricum leaves is attributed to the presence of phenolics compounds and the activation of endogenous antioxidant system / Actividad anticancerígena del extracto metanólico de hojas de Melastoma malabathricum atribuida a la presencia de compuestos fenólicos y a la activación del sistema antioxidante endógeno

Melastoma malabathricum (M. malabathricum) extracts have been reported to exert various pharmacological activities including antioxidants, anti-inflammatory and antiproliferative activities. The objective of the present study was to determine the anticarcinogenic activity of its methanol extract (MEMM) against the azoxymethane (AOM)-induced early colon carcinogenesis in rats. Rats were randomly assigned to five groups (n=6) namely normal control, negative control, and treatment (50, 250 or 500 mg/kg of MEMM) groups. Colon tissues were harvested for histopathological analysis and endogenous antioxidant system determination. MEMM was also subjected to HPLC analysis. Findings showed that MEMM significantly (p<0.05) reversed the AOM-induced carcinogenicity by: i) reducing the formation of aberrant crypt foci (ACF) in colon tissues, and; ii) enhancing the endogenous antioxidant activity (catalase, superoxide dismutase and glutathione peroxidase). Moreover, various phenolics has been identified in MEMM. In conclusion, MEMM exerts the in vivo anticarcinogenic activity via the activation of endogenous antioxidant system and synergistic action of phenolics.

Se ha informado que los extractos de Melastoma malabathricum (M. malabathricum) ejercen diversas actividades farmacológicas, incluidas actividades antioxidantes, antiinflamatorias y antiproliferativas. El objetivo del presente estudio fue determinar la actividad anticancerígena de su extracto de metanol (MEMM) contra la carcinogénesis de colon temprana inducida por azoximetano (AOM) en ratas. Las ratas se asignaron al azar a cinco grupos (n=6), a saber, los grupos de control normal, control negativo y tratamiento (50, 250 o 500 mg/kg de MEMM). Tejidos de colon fueron recolectados para análisis histopatológico y determinación del sistema antioxidante endógeno. MEMM también se sometió a análisis de HPLC. Los hallazgos mostraron que MEMM invirtió significativamente (p<0.05) la carcinogenicidad inducida por AOM al: i) reducir la formación de focos de criptas aberrantes (ACF) en los tejidos del colon, y; ii) potenciar la actividad antioxidante endógena (catalasa, superóxido dismutasa y glutatión peroxidasa). Además, se han identificado varios fenólicos en MEMM. En conclusión, MEMM ejerce la actividad anticancerígena in vivo mediante la activación del sistema antioxidante endógeno y la acción sinérgica de los fenólicos.

Modulação da concentração intracelular de NAD+ e seu efeito na tumorigênese induzida por benzo[a]pireno em células bronquiais epiteliais humanas / Modulation of intracellular concentration of NAD+ and its effect on benzo[a]pyrene-induced tumorigenesis in human epithelial bronchial cells

A alta incidência, prevalência e mortalidade do câncer de pulmão demonstram a necessidade de se identificar alterações moleculares envolvidas na carcinogênese pulmonar. Nesse contexto, a reprogramação do metabolismo energético é uma marca emergente do câncer. Há evidências de que benzo[a]pireno (B[a]P), um conhecido carcinógeno humano, induz alterações metabólicas via modificação da função mitocondrial tanto in vitro quanto in vivo. Uma vez que as alterações metabólicas não são somente o resultado da transformação celular, mas podem também ter papel na etiologia do câncer ao modular o epigenoma e a expressão de genes, intervir no metabolismo de células em processo de transformação pode contribuir para desvendar mecanismos de carcinogênese e revelar alvos para quimioprevenção. A fim de investigar a relação entre alterações no metabolismo celular, marcas epigenéticas e transformação celular, implementamos um modelo de tumorigênese (avaliada pela formação de colônias em soft-agar) induzida por B[a]P em células epiteliais bronquiais humanas imortalizadas (linhagem BEAS-2B) crescidas em monocamada (2D). O modelo possibilitou a observação de alterações precoces do metabolismo celular. Levando em consideração que o nucleotídeo NAD+ regula as atividades de diversas vias moleculares importantes para a sobrevivência, diferenciação, crescimento e morte celular, e que suas concentrações foram rapidamente diminuídas após exposição a B[a]P, decidimos suplementar as células BEAS-2B com nicotinamida ribosídeo (NR), um precursor intracelular de NAD+, concomitantemente à exposição a B[a]P. NR em baixa concentração no meio de cultura (1 µM) induziu estresse energético em células BEAS-2B expostas a B[a]P (1 µM) ao longo do período de uma semana de co-incubação, aumentando seletivamente a taxa de apoptose dessas células. Protegeu contra a transformação celular induzida por B[a]P e impediu completamente a formação espontânea de colônias das células controle em soft-agar. Usamos uma abordagem metabolômica direcionada a alvos específicos ("targeted metabolomics") desenvolvida no grupo para quantificar metabólitos conhecidamente alterados no câncer. Os dados indicam que NR diminui o metabolismo de glutamina nas células expostas a B[a]P, o que ocorre em paralelo com a diminuição das concentrações de citrato e aspartato, aumento da razão malato/aspartato, diminuição das razões ATP/AMP e ATP/ADP e aumento das concentrações de adenosina. As alterações se enquadram na hipótese de inibição do shuttle malato-aspartato, cuja atividade é necessária para a sobrevivência de células que sofrem o efeito Warburg (alta dependência de NADH citosólico para geração de ATP). NR adicionalmente protegeu as células contra o estresse redox, a hipermetilação do DNA e o aumento da atividade de sirtuína 1 (SIRT1) induzidos por B[a]P, além de aumentar a expressão de genes supressores tumorais (E-caderina, PTEN, semaforina 3F, p16(ink4a)) que podem ser reprimidos por CtBP (proteína ligante de NADH que atua como sensor redox e traduz a condição metabólica da célula para o controle da expressão gênica). Foi ainda observada maior atividade de PARP1 nas células expostas a B[a]P+NR em comparação aos demais grupos. Os resultados obtidos mostram que NR se contrapõe a ou exacerba alterações bioquímicas induzidas por B[a]P, diminuindo a chance de transformação carcinogênica das células BEAS-2B. Estudos em modelos mais complexos, como micro tecidos in vitro, são necessários para a confirmação do efeito quimiopreventivo da NR e alterações bioquímicas subjacentes

Tese de DoutoradoDOIhttps://doi.org/10.11606/T.9.2021.tde-05082021-095853DocumentoTese de DoutoradoAutorCordeiro, Everson Willian Fialho (Catálogo USP)Nome completoEverson Willian Fialho CordeiroE-mailE-mailUnidade da USPFaculdade de Ciências FarmacêuticasÁrea do ConhecimentoToxicologiaData de Defesa2021-04-08ImprentaSão Paulo, 2021OrientadorLoureiro, Ana Paula de Melo (Catálogo USP) Banca examinadoraLoureiro, Ana Paula de Melo (Presidente) Àvila, Daiana Silva de Meotti, Flavia Carla Silva, Eloiza Helena Tajara da Título em portuguêsModulação da concentração intracelular de NAD+ e seu efeito na tumorigênese induzida por benzo[a]pireno em células bronquiais epiteliais humanasPalavras-chave em portuguêsBenzo[a]pireno Câncer de pulmão Metabolismo energético Nicotinamida ribosídeo Resumo em portuguêsA alta incidência, prevalência e mortalidade do câncer de pulmão demonstram a necessidade de se identificar alterações moleculares envolvidas na carcinogênese pulmonar. Nesse contexto, a reprogramação do metabolismo energético é uma marca emergente do câncer. Há evidências de que benzo[a]pireno (B[a]P), um conhecido carcinógeno humano, induz alterações metabólicas via modificação da função mitocondrial tanto in vitro quanto in vivo. Uma vez que as alterações metabólicas não são somente o resultado da transformação celular, mas podem também ter papel na etiologia do câncer ao modular o epigenoma e a expressão de genes, intervir no metabolismo de células em processo de transformação pode contribuir para desvendar mecanismos de carcinogênese e revelar alvos para quimioprevenção. A fim de investigar a relação entre alterações no metabolismo celular, marcas epigenéticas e transformação celular, implementamos um modelo de tumorigênese (avaliada pela formação de colônias em soft-agar) induzida por B[a]P em células epiteliais bronquiais humanas imortalizadas (linhagem BEAS-2B) crescidas em monocamada (2D). O modelo possibilitou a observação de alterações precoces do metabolismo celular. Levando em consideração que o nucleotídeo NAD+ regula as atividades de diversas vias moleculares importantes para a sobrevivência, diferenciação, crescimento e morte celular, e que suas concentrações foram rapidamente diminuídas após exposição a B[a]P, decidimos suplementar as células BEAS-2B com nicotinamida ribosídeo (NR), um precursor intracelular de NAD+, concomitantemente à exposição a B[a]P. NR em baixa concentração no meio de cultura (1 µM) induziu estresse energético em células BEAS-2B expostas a B[a]P (1 µM) ao longo do período de uma semana de co-incubação, aumentando seletivamente a taxa de apoptose dessas células. Protegeu contra a transformação celular induzida por B[a]P e impediu completamente a formação espontânea de colônias das células controle em soft-agar. Usamos uma abordagem metabolômica direcionada a alvos específicos ("targeted metabolomics") desenvolvida no grupo para quantificar metabólitos conhecidamente alterados no câncer. Os dados indicam que NR diminui o metabolismo de glutamina nas células expostas a B[a]P, o que ocorre em paralelo com a diminuição das concentrações de citrato e aspartato, aumento da razão malato/aspartato, diminuição das razões ATP/AMP e ATP/ADP e aumento das concentrações de adenosina. As alterações se enquadram na hipótese de inibição do shuttle malato-aspartato, cuja atividade é necessária para a sobrevivência de células que sofrem o efeito Warburg (alta dependência de NADH citosólico para geração de ATP). NR adicionalmente protegeu as células contra o estresse redox, a hipermetilação do DNA e o aumento da atividade de sirtuína 1 (SIRT1) induzidos por B[a]P, além de aumentar a expressão de genes supressores tumorais (E-caderina, PTEN, semaforina 3F, p16(ink4a)) que podem ser reprimidos por CtBP (proteína ligante de NADH que atua como sensor redox e traduz a condição metabólica da célula para o controle da expressão gênica). Foi ainda observada maior atividade de PARP1 nas células expostas a B[a]P+NR em comparação aos demais grupos. Os resultados obtidos mostram que NR se contrapõe a ou exacerba alterações bioquímicas induzidas por B[a]P, diminuindo a chance de transformação carcinogênica das células BEAS-2B. Estudos em modelos mais complexos, como micro tecidos in vitro, são necessários para a confirmação do efeito quimiopreventivo da NR e alterações bioquímicas subjacentes.Título em inglêsModulation of intracellular concentration of NAD+ and its effect on benzo[a]pyrene-induced tumorigenesis in human epithelial bronchial cellsPalavras-chave em inglêsBenzo[a]pyrene Energetic metabolism Lung cancer Nicotinamide riboside Resumo em inglêsThe high incidence, prevalence and mortality of lung cancer demonstrates the need to identify molecular changes involved in lung carcinogenesis. In this context, the reprogramming of energy metabolism is an emerging brand of cancer. There is evidence that benzo[a]pyrene (B[a]P), a known human carcinogen, induces metabolic changes via modification of mitochondrial function both in vitro and in vivo. Since metabolic changes are not only the result of cell transformation, but can also play a role in the etiology of cancer by modulating the epigenome and gene expression, intervening in the metabolism of cells in the process of transformation can contribute to unravel mechanisms of carcinogenesis and reveal targets for chemoprevention. In order to investigate the relationship between changes in cell metabolism, epigenetic marks and cell transformation, we implemented a model of tumorigenesis (assessed by the formation of colonies on soft-agar) induced by B[a]P in immortalized human bronchial epithelial cells (BEAS-2B cell line human) grown in monolayer (2D). The model enabled the observation of early changes in cell metabolism. Taking into account that the NAD+ nucleotide regulates the activities of several molecular pathways important for cell survival, differentiation, growth and death, and that their concentrations were rapidly decreased after exposure to B[a]P, we decided to supplement the BEAS-2B cells with nicotinamide riboside (NR), an intracellular precursor of NAD+, concomitantly with exposure to B[a]P. NR in low concentration in the culture medium (1 µM) induced energy stress in BEAS-2B cells exposed to B[a]P (1 µM) over the period of a week of co-incubation, selectively increasing the apoptosis rate of these cells. It protected against cell transformation induced by B[a]P and completely prevented the spontaneous formation of control cell colonies on soft-agar. We use a targeted metabolomics approach developed in the group to quantify metabolites known to be altered in cancer. The data indicate that NR decreases the glutamine metabolism in cells exposed to B[a]P, which occurs in parallel with the decrease in citrate and aspartate concentrations, increased malate/aspartate ratio, decreased ATP/AMP and ATP/ADP ratios and increased adenosine concentrations. The changes fit the hypothesis of inhibition of the malate-aspartate shuttle, whose activity is necessary for the survival of cells that suffer the Warburg effect (high dependence on cytosolic NADH for ATP generation). NR additionally protected cells against redox stress, DNA hypermethylation and increased B[a]P-induced sirtuin 1 (SIRT1) activity, in addition to increasing the expression of tumor suppressor genes (E-cadherin, PTEN, semaphorin 3F, p16 (ink4a)) that can be suppressed by CtBP (NADH-binding protein that acts as a redox sensor and translates the cell's metabolic condition to control gene expression). Higher PARP1 activity was also observed in cells exposed to B[a]P+NR compared to the other groups. The results obtained show that NR is opposed to or exacerbates biochemical changes induced by B[a]P, reducing the chance of carcinogenic transformation of BEAS-2B cells. Studies on more complex models, such as micro tissues in vitro, are necessary to confirm the chemopreventive effect of NR and underlying biochemical changes

Ação Quimiopreventiva dos Fitoquímicos por meio da Regulação do Fator de Transcrição Nrf2: Revisão Integrativa da Literatura: Revisão Integrativa de Literatura / Quimiopreventive Action of Phytochemicals through Regulation of Transcription Factor Nrf2: Integrative Literature Review / Acción Quimiopreventiva de los Fitoquímicos a través de la Regulación del Factor de Transcripción Nrf2: Revisión Integradora de la Literatura

Introdução: O fator nuclear eritroide 2 relacionado ao fator 2 (Nrf2) desempenha papel fundamental na expressão de genes mediados por elemento de resposta antioxidante (ERA); sendo assim, é uma via importante para proteger as células de substâncias carcinogênicas. Objetivo: Realizar uma revisão integrativa da literatura acerca da ação quimiopreventiva dos fitoquímicos por meio da regulação do fator de transcrição Nrf2. Método: O levantamento de artigos para a revisão integrativa da literatura sobre essa temática foi realizado nos periódicos indexados nas bases de dados: Google Acadêmico, PubMed, SciELO, ScienceDirect e SpringerLink, utilizando-se os descritores advindos do MeSH: fitoquímicos, radicais livres, estresse oxidativo, carcinogênese, quimioprevenção e Nrf2. Os critérios de seleção foram artigos publicados de 2000 a 2019, relacionados, ou que investiguem diretamente a atuação de fitoquímicos no fator de transcrição Nrf2, e a prevenção do desenvolvimento de câncer. Resultados: Foram selecionados 58 artigos que estavam relacionados com o objetivo da revisão. Os estudos revisados apontaram que fitoquímicos, tais como resveratrol, curcumina, isotiocianato, luteolina, entre outros, atuam na ativação da via Nrf2, utilizando diferentes mecanismos, sendo eles dependentes ou independentes da proteína repressora Kelch-Like Epichlorohydrin-Associated Protein 1. Conclusão: Diante disso, conclui-se que a modulação do fator de transcrição Nrf2 é um mecanismo que se configura como um importante mediador no que concerne compostos nocivos ao organismo humano, e que a atuação dos fitoquímicos nessa via contribui para a redução do risco de câncer. No entanto, ainda não são completamente elucidados todos os mecanismos utilizados pelos fitoquímicos, sendo necessários ulteriores estudos na área

Introduction: The nuclear factor erythroid 2-related factor 2 (NRF2) plays a fundamental role in the expression of genes mediated by antioxidant response element (ARE), thus it is an important pathway to protect the cells from carcinogenic substances. Objective: To perform an integrative literature review on the quimiopreventive action of phytochemicals through regulation of the transcription factor Nrf2. Method: Search of papers for the integrative literature review about this theme conducted in journals indexed in the databases: Academic Google, PubMed, SciELO, ScienceDirect and Springer Link, using the MeSH descriptors: phytochemicals, free radicals, oxidative stress, carcinogenesis, chemoprevention and Nrf2. The selection criteria were articles published from 2000 to 2019, related to or that directly investigate the role of phytochemicals in the transcription factor Nrf2, and the prevention of cancer development. Results: 58 articles were selected, all related to the objective of the review. The reviewed studies showed that phytochemicals, such as resveratrol, curcumin, isothiocyanate, luteolin, among others, act on the activation of the Nrf2 pathway, using different mechanisms, which are dependent or independent of the repressor protein Kelch-Like Epichlorohydrin-Associated Protein 1. Conclusion: Therefore, the conclusion is that the modulation of the transcription factor Nrf2 is a mechanism that configures itself as an important mediator for harmful compounds to the human organism, and that the action of phytochemicals, in this pathway, contributes to the reduction of cancer risk. However, all the mechanisms used by phytochemicals, are not completely elucidated, and further studies are needed in the area

Introducción: El factor nuclear eritroide 2 relacionado con el factor 2 (Nrf2) desenvuelve un papel fundamental en la expresión de los genes mediados por él elemento de respuesta antioxidante (ERA), por lo tanto, es una vía importante para proteger las células de las sustancias carcinógenas. Objetivo: Realizar una revisión integradora de la literatura sobre la acción quimiopreventiva de los fitoquímicos mediante la regulación del factor de transcripción Nrf2. Método: El levantamiento de artículos para la revisión integral de la literatura sobre este tema se realizó en revistas indexadas en las bases de datos: Google Académico, PubMed, Scielo, ScienceDirect y SpringerLink, usando los descriptores MeSH: fitoquímicos, radicales libres, estrés oxidativo, carcinogénesis, quimioprevención y Nrf2. Los criterios de selección fueron artículos publicados entre 2000 y 2019, relacionados o que investigan directamente el papel de los fitoquímicos en el factor de transcripción Nrf2 y la prevención del desarrollo del câncer. Resultados: 58 artículos relacionados con el objetivo de la revisión fueron seleccionados. Los estudios revisados mostraron que los fitoquímicos, como el resveratrol, la curcumina, el isotiocito, la luteolina, entre otros, actúan sobre la activación de la vía Nrf2, utilizando diferentes mecanismos, que son dependientes o independientes de la proteína represora Kelch-Like Epichlorohydrin-Associated Protein 1. Conclusión: Por lo tanto, se concluí que la modulación del factor de transcripción Nrf2 es un mecanismo que se configura como un importante mediador en relación con los compuestos nocivos para el cuerpo humano, y que la acción de los fitoquímicos en esta vía contribuye a reducir el riesgo de cáncer. Sin embargo, todos los mecanismos utilizados por los fitoquímicos aún no se han dilucidado por completo, por lo que se necesitan más estudios en esta área

Expressão dos genes CYP1A1, CYP1B1, CYP2A6 e CYP2E1 em fumantes com câncer bucal / Expression of CYP1A1, CYP1B1, CYP2A6 and CYP2E1 in smokers with oral cancer

Os carcinógenos do tabaco estão relacionados a diversos tipos de câncer incluindo o carcinoma de células escamosas (CCE) bucal. Aliado ao álcool, o tabaco contribui para o desfecho desfavorável destes casos. A susceptibilidade individual ao câncer pode estar relacionada a expressão das enzimas que metabolizam tais carcinógenos. O objetivo deste trabalho é avaliar a expressão dos genes CYP1A1, CYP1B1, CYP2A6 e CYP2E1 no CCE bucal por meio de qPCR. Foram coletadas amostras de 32 indivíduos com CCE e de 15 controles submetidos a cirurgias bucais por lesões benignas. Foram constituídos quatro grupos: Grupo CCE fumante (n=26), Grupo CCE não fumante (n=6), Grupo controle fumante (n=9) e Grupo controle não fumante (n=6). O Teste de Fagerström para Dependência a Cigarros (TFDC) foi usado para avaliar a DN (DN) e AUDIT para avaliação do consumo de etílicos. Houve diminuição da expressão do gene CYP1B1 nos casos de CCE comparados aos controles. Foram encontradas diferenças estaticamente significativas de expressão gênica de CYP1B1 entre os Grupos CCE fumante e controle fumante (p=0,0018), Grupo CCE não fumante e controle não fumante (p=0,0079) e CCE fumante com CCE não fumante (p=0,0385) e entre os quatro grupos (p<0,0001). Houve diminuição da expressão do CYP2A6 no Grupo CCE fumante em relação ao Grupo controle, mas apenas um paciente do Grupo controle expressou este gene. Houve aumento da expressão de CYP2E1 entre os Grupos CCE fumante e controle fumante (p=0,0424). Concluindo, foi encontrada grande variabilidade interindividual no estudo da expressão dos genes estudados. Houve maior expressão de CYP1A1 e CYP2E1 em amostras de indivíduos fumantes com CCE. Os genes CYP1B1 e CYP2A6 estavam menos expressos no Grupo CCE fumante em relação ao Grupo controle. Para os genes CYP1B1 e CYP2E1 foram encontrados valores significativos na correlação entre a expressão gênica e parâmetros demográficos e de perfil tabágico no Grupo controle fumante, e do AUDIT no Grupo CCE não fumante. O gene CYP2E1, além de estar relacionado ao metabolismo do álcool, também deve ser considerado importante marcador do metabolismo dos carcinógenos derivados do tabaco

Tobacco carcinogens are related to various types of cancer, including oral squamous cell carcinoma (OSCC). Allied to alcohol, tobacco contributes to the unfavorable outcome of the cases. Individual cancer susceptibility may be related to an expression of the enzymes that metabolize such carcinogens. The aim of this work is to evaluate the expression of the genes CYP1A1, CYP1B1, CYP2A6 and CYP2E1 on OSCC by qPCR. Samples were collected from 32 individuals with OSCC and 15 controls submitted to oral surgeries due to benign lesions. There were four groups: Smoker SCC group (n = 26), nonsmoker SCC group (n = 6), Smoker control group (n = 9) and nonsmoker control group (n = 6). The Fagerström Test for Cigarette Dependence (TFCD) was used to evaluate nicotinic dependence (ND) and AUDIT for the evaluation of alcohol consumption. There was a decrease in CYP1B1 gene expression in cases of SCC compared to controls. (P = 0.0018); smoker CCE and non-smoker control (p = 0.0079); smoker SCC with nonsmoker SCC (p = 0.0385) and between the four groups (p <0.0001). There was a decreased expression in CYP2A6 in the smoker SCC Group compared to the control group, but only one control group patient expressed this gene. There was an increased expression of CYP2E1 between the smoking and nonsmoking SCC groups (p = 0.0424). In conclusion, large interindividual variability was found in the study of the expression of the genes studied. There was greater expression of CYP1A1 and CYP2E1 in samples from smokers with SCC. The CYP1B1 and CYP2A6 genes were less expressed in the smoker SCC Group. Significant values were found for the CYP1B1 and CYP2E1 genes in the correlation between a gene expression and a parameter and a non-smoker control group, non-smoker control group and AUDIT. The CYP2E1 gene, besides being related to alcohol metabolism, should also be considered an important marker of the metabolism of the carcinogens derived from tobacco

Estudo da expressão gênica dos principais metabolizadores de fase II de xenobióticos: GSTM1, GSTP1 e GSTT1 em carcinoma de células escamosas bucal / Study of the gene expression of the main xenobiotic phase II metabolizers: GSTM1, GSTP1 and GSTT1 in squamous cell carcinoma of the oral cavity

Tabaco e álcool são considerados os principais fatores de risco para o carcinoma de células escamosas (CCE) bucal contribuindo de maneira desfavorável para o tratamento e desfecho clínico. Seus carcinógenos são metabolizados em duas fases, sendo a segunda fase realizada pelas Glutationa S-transferases (GSTs). O objetivo do presente estudo foi avaliar a expressão gênica da forma selvagem dos genes GSTM1, GSTP1 e GSTT1 por qPCR em 33 amostras de CCE bucal de fumantes, ex-fumantes e não fumantes, e 15 controles em busca de uma correlação clínica com consumo de tabaco, álcool e estadiamento clínico. A dependência nicotínica foi avaliada pelo Teste de Fagerström pra Dependência a Cigarros (TFDC) e para consumo de etílicos o Teste AUDIT. Foi observado aumento da expressão de GSTM1 no Grupo CCE fumante em relação ao Grupo Controle (p=0,0161). Contrariamente, foi encontrada uma menor expressão de GSTT1 no Grupo CCE fumante em relação ao Grupo Controle fumante (p=0,0183). No grupo CCE fumante não foi encontrada uma correlação entre a expressão dos genes estudados e fatores ligados ao tabagismo, etilismo e estadiamento clinico. No grupo Controle fumante, houve correlação entre teste AUDIT e a expressão de GSTM1 (p=0,0000). Para GSTP1 e GSTT1 houve correlação entre a expressão quando comparada a idade do paciente (p=0,0008; p=0,0095), idade de inicio do tabagismo (p=0,0033; p=0,0081), TFDC (p=0,0102; p=0,0085) e AUDIT (p=0,0052; p=0,0219) respectivamente. Para GSTT1 foi encontrada uma correlação entre a expressão e número de cigarros/dia (p=0,0175). Concluímos que as formas selvagens das GSTs estudadas apresentaram uma alta expressão nas amostras de CCE bucal, entretanto, quantitativamente essa expressão foi baixa, com grande variabilidade interindividual. Outrossim, não houve uma correlação direta entre níveis de expressão, carga tabágica, TFDC, teste AUDIT e estadiamento clínico. O aumento da expressão de GSTM1 e GSTP1 parece não ter tido um efeito protetor. A baixa expressão de GSTT1 em pacientes fumantes com CCE bucal se mostrou um potencial marcador a ser avaliado em pacientes fumantes que ainda não desenvolveram uma neoplasia maligna(AU)

Tobacco and alcohol are considered to be the main risk factors for oral squamous cell carcinoma (SCC), contributing to treatment and clinical outcome. Its carcinogens are metabolized in two phases, being the second phase carried out by Glutathione Stransferases (GSTs). The objective of the present study was to evaluate the wild-type gene expression of the GSTM1, GSTP1 and GSTT1 genes by qPCR in 33 samples of oral SCC from smokers, former smokers and nonsmokers, and 15 controls looking for a clinical correlation with tobacco and alcohol consumption and clinical staging. Nicotinic dependence was assessed by the Fagerström Test for Cigarette Dependence (TFCD) and alcohol consumption by the AUDIT Test. Increased expression of GSTM1 in the Smoker SCC Group was observed in relation to the Control Group (p=0.0161). Conversely, a lower expression of GSTT1 was found in the smoker SCC group compared to the Smoker Control Group (p=0.0183). In the smoker SCC group, no correlation was found between the genes expression studied and factors related to smoking, alcoholism and clinical staging. In the Smoker Control Group, there was a correlation between the AUDIT test and the GSTM1 expression (p=0.0000). For GSTP1 and GSTT1, there was a correlation between the expression compared with the patient's age (p=0.0008, p=0.0095), age of starting smoking (p=0.0033, p=0.0081), FTCD (p=0.0102, p=0.0085) and AUDIT (p=0.0052, p=0.0219) respectively. For GSTT1 a correlation was found between expression and number of cigarettes/day (p=0.0175). We concluded that the wild forms of the GSTs studied presented a high expression in the samples of oral SCC; however, quantitatively this expression was low, with great interindividual variability. Also, there was no direct correlation between levels of expression, pack-years, FTCD, AUDIT Test and clinical stage. Increased expression of GSTM1 and GSTP1 appears to have had no protective effect. The low GSTT1 expression in smokers with oral SCC was shown to be a potential marker to be evaluated in smoker patients who have not yet developed a malignant neoplasm(AU)

Effect of letrozole in carcinogen-plus-estrogen-induced endometrial hyperplasia in mice

PURPOSE: To evaluate the effects of letrozole (Ltz) in carcinogen+estrogen-induced endometrial hyperplasia. METHODS: BALB/c female mice were divided into four groups of 12 animals each receiving an intrauterine dose of N-ethyl-N-nitrosourea (ENU) and weekly subcutaneous injections of estradiol hexaidrobenzoate (EHB), except for group I(control). The groups were divided in I (control), II (ENU+EHB), III (ENU+EHB+MPA) and IV (ENU+EHB+Ltz). Group III also received intramuscular injections of MPA (medroxy progesterone acetate) every four weeks, while group IV received oral doses of Ltz daily. At the end of 16 weeks, the animals were sacrificed, and blood samples were collected for the measurement of serum estradiol and progesterone levels. Uterine histological sections were made to evaluate the presence of endometrial proliferative lesions. Differences between groups were evaluated with student's t test, ANOVA and chi-square test. RESULTS: Groups ENU+EHB, ENU+EHB+MPA and ENU+EHB+Ltz showed varying degrees of endometrial hyperplasia. The incidence of hyperplasia in groups ENU+EHB and ENU+EHB+Ltz was higher and more severe than in group ENU+EHB+MPA. Control group showed lower levels of serum estradiol than the other groups. CONCLUSION: There was no evidence that letrozole could act as an antiestrogenic drug in the development of endometrial proliferative lesions.

DNA methylation regulates expression of VEGF-C, and S-adenosylmethionine is effective for VEGF-C methylation and for inhibiting cancer growth

DNA hypomethylation may activate oncogene transcription, thus promoting carcinogenesis and tumor development. S-adenosylmethionine (SAM) is a methyl donor in numerous methylation reactions and acts as an inhibitor of intracellular demethylase activity, which results in hypermethylation of DNA. The main objectives of this study were to determine whether DNA hypomethylation correlated with vascular endothelial growth factor-C (VEGF-C) expression, and the effect of SAM on VEGF-C methylation and gastric cancer growth inhibition. VEGF-C expression was assayed by Western blotting and RT-qPCR in gastric cancer cells, and by immunohistochemistry in tumor xenografts. VEGF-C methylation was assayed by bisulfite DNA sequencing. The effect of SAM on cell apoptosis was assayed by flow cytometry analyses and its effect on cancer growth was assessed in nude mice. The VEGF-C promoters of MGC-803, BGC-823, and SGC-7901 gastric cancer cells, which normally express VEGF-C, were nearly unmethylated. After SAM treatment, the VEGF-C promoters in these cells were highly methylated and VEGF-C expression was downregulated. SAM also significantly inhibited tumor growth in vitro and in vivo. DNA methylation regulates expression of VEGF-C. SAM can effectively induce VEGF-C methylation, reduce the expression of VEGF-C, and inhibit tumor growth. SAM has potential as a drug therapy to silence oncogenes and block the progression of gastric cancer.

Targeting PPM1D by lentivirus-mediated RNA interference inhibits the tumorigenicity of bladder cancer cells

Protein phosphatase magnesium/manganese-dependent 1D (PPM1D) is a p53-induced phosphatase that functions as a negative regulator of stress response pathways and has oncogenic properties. However, the functional role of PPM1D in bladder cancer (BC) remains largely unknown. In the present study, lentivirus vectors carrying small hairpin RNA (shRNA) targeting PPM1D were used to explore the effects of PPM1D knockdown on BC cell proliferation and tumorigenesis. shRNA-mediated knockdown of PPM1D significantly inhibited cell growth and colony forming ability in the BC cell lines 5637 and T24. Flow cytometric analysis showed that PPM1D silencing increased the proportion of cells in the G0/G1 phase. Downregulation of PPM1D also inhibited 5637 cell tumorigenicity in nude mice. The results of the present study suggest that PPM1D plays a potentially important role in BC tumorigenicity, and lentivirus-mediated delivery of shRNA against PPM1D might be a promising therapeutic strategy for the treatment of BC.

Potential chemoprotective effects of green propolis, L-lysine and celecoxib on bone marrow cells and peripheral blood lymphocytes of Wistar rats subjected to bladder chemical carcinogenesis

PURPOSE: To evaluate the genotoxicity of propolis and L-lysine, as well as their effects on the possible cellular damage in erythroblasts (bone marrow) and leukocytes (peripheral blood) caused by the carcinogen BBN (n - butyl - n {4 - hydroxybutyl} nitrosamine) in rats subjected to bladder carcinogenesis and treated with green propolis and L-lysine. METHODS: One hundred and twenty five rats were distributed into the following groups: I, IIA, IIB, III, K, L M N, X, XI, XII and XIII. Groups I to X received BBN in drinking water for 14 weeks (wks). Group I was treated with intragastric (ig) propolis at 150 mg/kg body weight, for 44 wks, beginning 30 days before start of BBN. Groups IIA and III were treated with propolis (150 mg/kg), for 40 wks, subcutaneous (sc) and ig, respectively, beginning simultaneously with BBN. On the 32nd wk, the animals of groups L, M and N were treated ig with L-lysine (300 mg/kg), celecoxib (30 mg/kg) and propolis (300 mg/kg), respectively, up to the 40th wk. The groups that received only BBN (IIB and K) were treated with water, sc and orally, respectively, for 40 wks. Groups XI, XII and XIII received respectively propolis (150 mg/kg), L-lysine (150 mg/kg) and water ig for 40 wks. After 40 wks, the surviving animals were anesthetized and subjected to femoral bone marrow aspiration and blood collection from the aorta, for CA and MNT, respectively, for investigation of genotoxicity. RESULTS: Groups IIB and K, which received only BBN and water, showed the greatest DNA damage in peripheral leukocytes (CA) and largest number of micronuclei in bone marrow erythrocytes (MNT) in relation to all other groups that received BBN and lysine and/or propolis (p<0.001). CONCLUSIONS: Both propolis and L-lysine are effective in protecting against genotoxicity, as well not being genotoxic themselves toward the cells evaluated, at the doses and times administered and according to the two tests utilized. .

Liver cancer stem cells are selectively enriched by low-dose cisplatin

Accumulating evidence has indicated the importance of cancer stem cells in carcinogenesis. The goal of the present study was to determine the effect of low-dose cisplatin on enriched liver cancer stem cells (LCSCs). Human hepatoblastoma HepG2 cells were treated with concentrations of cisplatin ranging from 1 to 5 μg/mL. Cell survival and proliferation were evaluated using a tetrazolium dye (MTT) assay. LCSCs were identified using specific markers, namely aldehyde dehydrogenase-1 (ALDH1) and CD133. The percentage of ALDH1+ or CD133+ cells was examined by flow cytometric analysis. The expression of ALDH1 and/or CD133 in HepG2 cells was determined by immunocytochemical analysis. Low-dose cisplatin treatment significantly decreased cell survival in HepG2 cells after 24 or 72 h. However, the percentage of LCSCs in the surviving cells was greatly increased. The percentage of ALDH1+ or CD133+ cells was increased in a time- and dose-dependent manner after treatment with 1-4 μg/mL cisplatin, whereas 5 μg/mL cisplatin exposure slightly reduced the number of positive cells. These findings indicate that low-dose cisplatin treatment may efficiently enrich the LCSC population in HepG2 cells.

Chemopreventive effect of Brazilian green propolis on experimental dermal carcinogenesis in murine model / Efecto quimiopreventivo del propóleos verde brasileño sobre la carcinogénesis cutánea en el modelo murino experimental

The aim of this study was to assess the effect of oral administration of Hydroalcoholic Extract of Green Propolis (HEGP) on dermal carcinogenesis in rodent model. For the biological assay, we used 36 mice, assigned into 6 groups (n=6): CTR (treated with 100 mg/kg HEGP and no tumor induction), TUM (treated with water and tumor induction), GP10 (treated with 10 mg/kg HEGP and tumor induction), GP50 (treated with 50 mg/kg HEGP and tumor induction) and GP100 (treated with 100 mg/kg HEGP and tumor induction). Cancer induction was performed in the back of the mice by topical application of DMBA. After 16 weeks, mice were euthanized and their backs were submitted to post-mortem histological analysis. The mean number of lesions developed in TUM (4.14±0.89) was significantly higher than in GP10 (2.05±1.02), GP50 (1.8±1.92) and GP100 (2.5±1.73) (p<0.05). The tumors formed in HEGP-treated groups were histologically more differentiated, but only in PV100 in situ lesions were evidenced. Infiltration of anatomical noble structures was less frequent in HEGP-treated groups (p<0.05). Our data suggest that oral administration of HEGP provided partial inhibition of DMBA-induced dermal carcinogenesis, as well as appeared to modulate the differentiation and infiltrative potential of the carcinomas in rodent model.

El objetivo de este estudio fue evaluar el efecto de la administración oral de extracto hidroalcohólico del propóleos verde (HEGP) sobre la carcinogénesis dérmica en modelo de roedores. Para el ensayo biológico, se utilizaron 36 ratones asignados en 6 grupos (n = 6): CTR (tratado con 100 mg/kg HEGP y sin inducción de tumores), TUM (tratada con agua e inducción de tumores), GP10 (tratado con 10 mg/kg HEGP e inducción de tumores), GP50 (tratado con 50 mg/kg HEGP e inducción de tumores) y GP100 (tratado con 100 mg/kg HEGP e inducción de tumores). La inducción de cáncer se llevó a cabo en la región dorsal de los ratones por aplicación tópica de DMBA. Después de 16 semanas, los ratones fueron sacrificados y sus dorsos fueron sometidos a análisis histológico post-mortem. El número medio de lesiones desarrolladas en TUM (4,14±0,89) fue significativamente mayor que GP10 (2,05±1,02), GP50 (1,8±1,92) y gp100 (2,5±1,73) (p<0,05). Los tumores formados en grupos tratados con HEGP fueron histológicamente más diferenciados, pero sólo en PV100 las lesiones in situ fueron manifiestas. La infiltración de las estructuras anatómicas blanco fue menos frecuente en los grupos tratados con HEGP (p<0,05). Nuestros datos sugieren que la administración oral de HEGP proporciona una inhibición parcial de la carcinogénesis dérmica inducida por DMBA, así como pareció modular la diferenciación y potencial infiltrante de los carcinomas en el modelo animal.

Anti-carcinogenic potential of Euphorbia neriifolia leaves and isolated flavonoid against N-Nitrosodiethylamine-induced renal carcinogenesis in mice.

Anti-carcinogenic potential of hydro-ethanolic extract of Euphorbia neriifolia (EN) leaves and an isolated flavonoid (ENF) was investigated against N-Nitrosodiethylamine (DENA)-induced renal carcinogenesis in mice. Experimental mice were pretreated with 150 and 400 mg/kg body wt of EN, 0.5% and 1% mg/kg body wt of butylated hydroxylanisole (BHA) as a standard antioxidant and 50 mg/kg body wt of ENF for 21 days prior to the administration of a single dose of 50 mg/kg body wt of DENA. Levels of renal markers (urea and creatinine), xenobiotic metabolic enzymes (Cyt P450 and Cyt b5), lipid peroxidation (LPO), antioxidants (SOD, CAT, GST and GSH) and other biochemical parameters — AST, ALT, ALP, total protein (TP), and total cholesterol (TC) were measured to determine the renal carcinogenesis caused by DENA. DENA administration significantly (p<0.001) decreased the body weight and increased the tissue weight. It significantly (p<0.001) enhanced the levels of Cyt P450, Cyt b5 and LPO and decreased the levels of SOD, CAT, GST and GSH content. The activities of AST, ALT and ALP and the TP content and renal markers were also significantly decreased (p<0.001), while TC level was markedly increased after DENA administration, as compared with the normal control group (p<0.001). Pretreatment with EN and ENF counteracted DENA-induced oxidative stress (LPO) and exerted its protective effects by restoring the levels of antioxidants (SOD, CAT, GST and GSH), biochemical parameters (AST, ALT, ALP, TP and TC), renal markers (urea and creatinine) and xenobiotic enzymes (Cyt P450 and Cyt b5) in renal tissue. In conclusion, the present study showed significant anti-carcinogenic potential of the hydro-ethanolic extract of E. neriifolia and ENF against DENA-induced renal carcinogenicity.

Repercussão hepática da carcinogênese colorretal induzida pelo azoximetano / Hepatic repercussions of azoxymethane-induced colorectal carcinogenesis

OBJETIVO: Avaliar as repercussões hepáticas da carcinogênese colônica induzida por diferentes doses e tempos de exposição ao azoximetano em ratos Wistar. MÉTODOS: Quarenta e quatro ratos foram distribuídos em quatro grupos. Os animais tinham oito semanas no início do experimento. No grupo 1, receberam 1.0mL de solução salina intraperitonealmente uma vez por semana por duas semanas. No grupo 2, receberam 15 mg/kg de azoximetano intraperitonealmente uma vez por semana por duas semanas. Esses animais foram mortos na 15ª semana do experimento. Os animais do grupo 3 receberam solução salina intraperitonealmente uma vez por semana por duas semanas. Os animais do grupo 4 receberam 20mg/kg de azoximetano intraperitonealmente uma vez por semana por duas semanas. Esses animais foram mortos na 26ª semana do experimento. Os fragmentos de tecido hepático foram corados pela hematoxilina e eosina e avaliadas microscopicamente. RESULTADOS: Grupo 1 e grupo 2 diferiram significantemente em relação a esteatose, mas não houve diferença entre o grupo 3 e o grupo 4. No entanto, no grupo 4 foram observadas lesões pré-neoplásicas (focos de células alteradas, claras, vacuoladas, basofílicas, anfofílicas, tigróides, oncocíticas, pequenas ou acidófilas, espongioses e pelioses) e lesões neoplásicas (colangiomas e adenomas) contendo hepatócitos atípicos de permeio, não identificados no grupo 3. CONCLUSÃO: No modelo de carcinogênese colorretal, lesões hepáticas pré-neoplásicas e neoplásicas aparecem e evoluem na proporção do tempo e dose de exposição ao azoximetano.

OBJECTIVE: To evaluate the hepatic effects of colonic carcinogenesis induced by azoxymethane at different doses and times of exposure in rats. METHODS: Forty-four Wistar rats were divided into four groups. The animals were eight weeks at the beginning of the experiment. group 1 received 1.0ml of saline intraperitoneally once a week for two weeks. Group 2 received 15 mg/kg of azoxymethane intraperitoneally once a week for two weeks. These animals were killed at the 15th week of the experiment. The animals of group 3 received saline intraperitoneally once a week for two weeks. Group 4 animals received 20mg/kg of azoxymethane intraperitoneally once a week for two weeks. These animals were killed at the 26th week of the experiment. The fragments of liver tissue were stained with hematoxylin and eosin and evaluated microscopically. RESULTS: Groups 1 and 2 differed significantly in relation to steatosis, no difference having been found between group 3 and group 4. However, in group 4 we observed pre-neoplastic lesions (foci of altered, clear, vacuolated, basophilic, amphophilic tigroid, oncocytic, small or acidophilus cells, spongiosis and peliosis) and neoplastic lesions (adenomas and colangiomas) containing atypical hepatocytes in between, not identified in group 3. CONCLUSION: In the model of colorectal carcinogenesis, preneoplastic and neoplastic hepatic lesions appear and evolve in proportion to the time of exposure and dose of azoxymethane.

Chemopreventive effect of Ardisia crispa hexane fraction on the peri-initiation phase of mouse skin tumorigenesis

To investigate the chemopreventive effect of the hexane extract of Ardisia crispa during the peri-initiation phase of mouse skin tumorigenesis. This study was conducted for 12 weeks on two-stage 7,12-dimethylbenz[alpha]-anthracene [DMBA]-induced tumor initiation followed by croton-oil-induced tumor promotion in mice. A. crispa root hexane extract [ACRH] was applied at various doses [30, 100, 300 mg/kg] 7 days prior to and after DMBA treatment. Throughout the study, morphological observations, i.e., tumor incidence, tumor volume and tumor burden were measured for each of the treated groups. At the end of the experiment, the mice were sacrificed and their skin tissues were examined histopathologically. The highest dose of ACRH [300 mg/kg] significantly delayed tumor formation [week 9, p < 0.05] and exhibited the lowest tumor volume [0.71 +/- 0.00 mm[3], p < 0.05], tumor burden [2.00 +/- 0.00, p < 0.05], and tumor incidence [16.67%, p < 0.05] compared to other doses of ACRH. A 100-mg/kg dose produced tumor latency at week 7, tumor volume of 2.44 +/- 0.88 mm[3] [p < 0.05], tumor burden of 1.60 +/- 0.60 [p < 0.05], and tumor incidence of 50%; 30 mg/kg produced tumor latency at week 8, tumor volume of 2.04 +/- 0.45 mm[3] [p < 0.05], tumor burden of 2.17 +/- 0.54, tumor incidence of 60% and carcinogen control [tumor latency at week 7; tumor volume, 3.56 mm3; tumor incidence of 66.67%].The highest dose of A. crispa hexane extract delayed tumor development, thus showing a chemopreventive effect on mouse skin tumorigenesis

[ promising extract suppresses cellular proliferation during the initiation phase of chemically induced colon carcinogenesis]

The present study was undertaken to investigate the chemopreventive efficacy of the ethanolic extract of indigenous Nigella sativa [NsE] seeds during the initiation phase of 1,2- dimethylhydrazine [DMH]-induced colon carcinogenesis in a rat model, and to appraise its potential impact on cellular proliferation. The results demonstrated that [NsE], at an orally daily dose equivalent to 150 mg of the seeds/kg body weight, has an inhibitory effect against colon carcinogenesis as reflected by significant reductions in tumor incidence, multiplicity and mean tumor volumes. These reductions were accompanied by a significant decrease in colonic proliferating cell nuclear antigen-Labeling index [PCNA-LI]. In conclusion, we provided evidence that [NsE] has a chemopreventive effect against DMH- induced colon carcinogenesis. We surmise that such effect of [NsE] is mediated, at least in part, through its ability to suppress cellular proliferation. The results could provide an effective chemopreventive approach in the primary prevention of colon cancer in humans in the next future

Cancer cell metabolism: implications for therapeutic targets

Cancer cell metabolism is characterized by an enhanced uptake and utilization of glucose, a phenomenon known as the Warburg effect. The persistent activation of aerobic glycolysis in cancer cells can be linked to activation of oncogenes or loss of tumor suppressors, thereby fundamentally advancing cancer progression. In this respect, inhibition of glycolytic capacity may contribute to an anticancer effect on malignant cells. Understanding the mechanisms of aerobic glycolysis may present a new basis for cancer treatment. Accordingly, interrupting lactate fermentation and/or other cancer-promoting metabolic sites may provide a promising strategy to halt tumor development. In this review, we will discuss dysregulated and reprogrammed cancer metabolism followed by clinical relevance of the metabolic enzymes, such as hexokinase, phosphofructokinase, pyruvate kinase M2, lactate dehydrogenase, pyruvate dehydrogenase kinase and glutaminase. The proper intervention of these metabolic sites may provide a therapeutic advantage that can help overcome resistance to chemotherapy or radiotherapy.