RESUMEN
Esophageal squamous cell carcinoma (ESCC) is among the ten most frequent and deadly cancers, without effective therapies for most patients. More recently, drugs targeting deregulated growth factor signaling receptors have been developed, such as HGF-MET targeted therapy. We assessed MET and HGF genetic alterations and gene and protein expression profiles in ESCC patients from the Brazilian National Cancer Institute and publicly available datasets, as well as the intratumor heterogeneity of the alterations found. Our analyses showed that HGF and MET genetic alterations, both copy number and mutations, are not common in ESCC, affecting 5 and 6% of the cases, respectively. HGF showed a variable mRNA expression profile between datasets, with no alterations (GSE20347), downregulation (GSE45670), and upregulation in ESCC (our dataset and GSE75241). On the other hand, MET was found consistently upregulated in ESCC compared to non-tumor surrounding tissue, with median fold-changes of 5.96 (GSE20347), 3.83 (GSE45670), 6.02 (GSE75241), and 5.0 (our dataset). Among our patients, 84% of the tumors showed at least a two-fold increase in MET expression. This observation was corroborated by protein levels, with 55% of cases exhibiting positivity in 100% of the tumor cells. Intratumor heterogeneity was evaluated in at least four tumor biopsies from five patients and two cases showed a consistent increase in MET expression (at least two-fold) in all tumor samples. Our data suggested that HGF-MET signaling pathway was likely to be overactivated in ESCC, representing a potential therapeutic target, but eligibility for this therapy should consider intratumor heterogeneity.
Asunto(s)
Carcinoma de Células Escamosas , Neoplasias Esofágicas , Carcinoma de Células Escamosas de Esófago , Neoplasias de Cabeza y Cuello , Brasil , Carcinoma de Células Escamosas/genética , Línea Celular Tumoral , Neoplasias Esofágicas/genética , Carcinoma de Células Escamosas de Esófago/genética , Regulación Neoplásica de la Expresión Génica , Humanos , Proteínas Proto-Oncogénicas c-met/genética , Proteínas Proto-Oncogénicas c-met/metabolismoRESUMEN
Esophageal squamous cell carcinoma (ESCC) is among the ten most frequent and deadly cancers, without effective therapies for most patients. More recently, drugs targeting deregulated growth factor signaling receptors have been developed, such as HGF-MET targeted therapy. We assessed MET and HGF genetic alterations and gene and protein expression profiles in ESCC patients from the Brazilian National Cancer Institute and publicly available datasets, as well as the intratumor heterogeneity of the alterations found. Our analyses showed that HGF and MET genetic alterations, both copy number and mutations, are not common in ESCC, affecting 5 and 6% of the cases, respectively. HGF showed a variable mRNA expression profile between datasets, with no alterations (GSE20347), downregulation (GSE45670), and upregulation in ESCC (our dataset and GSE75241). On the other hand, MET was found consistently upregulated in ESCC compared to non-tumor surrounding tissue, with median fold-changes of 5.96 (GSE20347), 3.83 (GSE45670), 6.02 (GSE75241), and 5.0 (our dataset). Among our patients, 84% of the tumors showed at least a two-fold increase in MET expression. This observation was corroborated by protein levels, with 55% of cases exhibiting positivity in 100% of the tumor cells. Intratumor heterogeneity was evaluated in at least four tumor biopsies from five patients and two cases showed a consistent increase in MET expression (at least two-fold) in all tumor samples. Our data suggested that HGF-MET signaling pathway was likely to be overactivated in ESCC, representing a potential therapeutic target, but eligibility for this therapy should consider intratumor heterogeneity.
Asunto(s)
Humanos , Neoplasias Esofágicas/genética , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas de Esófago/genética , Neoplasias de Cabeza y Cuello , Brasil , Regulación Neoplásica de la Expresión Génica , Proteínas Proto-Oncogénicas c-met/genética , Proteínas Proto-Oncogénicas c-met/metabolismo , Línea Celular TumoralRESUMEN
The International Agency for Research on Cancer (IARC) and the US National Cancer Institute (NCI) have initiated a series of cancer-focused seminars [Scelo G, Hofmann JN, Banks RE et al. International cancer seminars: a focus on kidney cancer. Ann Oncol 2016; 27(8): 1382-1385]. In this, the second seminar, IARC and NCI convened a workshop in order to examine the state of the current science on esophageal squamous cell carcinoma etiology, genetics, early detection, treatment, and palliation, was reviewed to identify the most critical open research questions. The results of these discussions were summarized by formulating a series of 'difficult questions', which should inform and prioritize future research efforts.
Asunto(s)
Carcinoma de Células Escamosas , Neoplasias Esofágicas , Internacionalidad , Carcinoma de Células Escamosas/epidemiología , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/terapia , Detección Precoz del Cáncer , Neoplasias Esofágicas/epidemiología , Neoplasias Esofágicas/genética , Neoplasias Esofágicas/terapia , Carcinoma de Células Escamosas de Esófago , Humanos , Factores de RiesgoRESUMEN
Early nutrition plays a long-term role in the predisposition to chronic diseases and influences the metabolism of several drugs. This may happen through cytochromes P450 (CYPs) regulation, which are the main enzymes responsible for the metabolism of xenobiotics. Here, we analyzed the effects of maternal protein restriction (MPR) on the expression and activity of hepatic offspring's CYPs during 90 days after birth, using Wistar rats as a mammal model. Hepatic CYP1A1, CYP1A2, CYP2B1, CYP2B2 and CYP2E1 mRNA and protein expression, and associated catalytic activities (ECOD, EROD, MROD, BROD, PROD and PNPH) were evaluated in 15-, 30-, 60-, and 90-day-old offspring from dams fed with either a 0% protein (MPR groups) or a standard diet (C groups) during the 10 first days of lactation. Results showed that most CYP genes were induced in 60- and 90-day-old MPR offspring. The inductions detected in MPR60 and MPR90 were of 5.0- and 2.0-fold (CYP1A2), 3.7- and 2.0-fold (CYP2B2) and 9.8- and 5.8- fold (CYP2E1), respectively, and a 3.8-fold increase of CYP2B1 in MPR90. No major alterations were detected in CYP protein expression. The most relevant CYP catalytic activities' alterations were observed in EROD, BROD and PNPH. Nevertheless, they did not follow the same pattern observed for mRNA expression, except for an induction of EROD in MPR90 (3.5-fold) and of PNPH in MPR60 (2.2-fold). Together, these results suggest that MPR during lactation was capable of altering the expression and activity of the hepatic CYP enzymes evaluated in the offspring along development.
Asunto(s)
Sistema Enzimático del Citocromo P-450/metabolismo , Dieta con Restricción de Proteínas , Lactancia/metabolismo , Hígado/enzimología , Animales , Hidrocarburo de Aril Hidroxilasas/metabolismo , Citocromo P-450 CYP1A1/metabolismo , Citocromo P-450 CYP1A2/metabolismo , Citocromo P-450 CYP2B1/metabolismo , Citocromo P-450 CYP2E1/metabolismo , Femenino , Modelos Animales , Ratas , Ratas Wistar , Esteroide Hidroxilasas/metabolismo , Factores de TiempoRESUMEN
Cytochrome P450 (CYP) is a superfamily of enzymes involved in the metabolism of endogenous compounds and xenobiotics. CYP2A6 catalyzes the oxidation of nicotine and the activation of carcinogens such as aflatoxin B1 and nitrosamines. CYP2E1 metabolizes ethanol and other low-molecular weight compounds and can also activate nitrosamines. The CYP2A6 and CYP2E1 genes are polymorphic, altering their catalytic activities and susceptibility to cancer and other diseases. A number of polymorphisms described are ethnic-dependent. In the present study, we determined the genotype and allele frequencies of the main CYP2A6 and CYP2E1 polymorphisms in a group of 289 volunteers recruited at the Central Laboratory of Hospital Universitário Pedro Ernesto. They had been residing in the city of Rio de Janeiro for at least 6 months and were divided into two groups according to skin color (white and non-white). The alleles were determined by allele specific PCR (CYP2A6) or by PCR-RFLP (CYP2E1). The frequencies of the CYP2A6*1B and CYP2A6*2 alleles were 0.29 and 0.02 for white individuals and 0.24 and 0.01 for non-white individuals, respectively. The CYP2A6*5 allele was not found in the population studied. Regarding the CYP2E1*5B allele, we found a frequency of 0.07 in white individuals, which was statistically different (P < 0.05) from that present in non-white individuals (0.03). CYP2E1*6 allele frequency was the same (0.08) in both groups. The frequencies of CYP2A6*1B, CYP2A6*2 and CYP2E1*6 alleles in Brazilians are similar to those found in Caucasians and African-Americans, but the frequency of the CYP2E1*5B allele is higher in Brazilians.
Asunto(s)
Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Hidrocarburo de Aril Hidroxilasas/genética , /genética , Genética de Población , Frecuencia de los Genes/genética , Oxigenasas de Función Mixta/genética , Polimorfismo Genético/genética , Población Negra/genética , Brasil/etnología , Población Blanca/genética , Genotipo , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de RestricciónRESUMEN
Cytochrome P450 (CYP) 2A enzymes are involved in the metabolism of numerous drugs and hormones and activate different carcinogens. Human CYP2A6, mouse CYP2A5 and rat CYP2A3 are orthologous enzymes that present high similarity in their amino acid sequence and share substrate specificities. However, different from the human and mouse enzyme, CYP2A3 is not expressed in the rat liver. There are limited data about expression of CYP2A3 in extrahepatic tissues and its regulation by typical CYP inducers. Therefore, the objective of the present study was to analyze CYP2A3 mRNA expression in different rat tissues by RT-PCR, and to study the influence of 3-methylcholanthrene, pyrazole and -ionone treatment on its expression. Male Wistar rats were divided into four groups of 5 rats each, and were treated ip for 4 days with 3-methylcholanthrene (25 mg/kg body weight), pyrazole (150 mg/kg body weight), -ionone (1 g/kg body weight), or vehicle. Total RNA was extracted from tissues and CYP2A3 mRNA levels were analyzed by semiquantitative RT-PCR. CYP2A3 mRNA was constitutively expressed in the esophagus, lung and nasal epithelium, but not along the intestine, liver, or kidney. CYP2A3 mRNA levels were increased in the esophagus by treatment with 3-methylcholanthrene and pyrazole (17- and 7-fold, respectively), in lung by pyrazole and -ionone (3- and 4-fold, respectively, although not statistically significant), in the distal part of the intestine and kidney by 3-methylcholanthrene and pyrazole, and in the proximal part of the intestine by pyrazole. CYP2A3 mRNA was not induced in nasal epithelium, liver or in the middle part of the intestine. These data show that, in the rat, CYP2A3 is constitutively expressed in several extrahepatic tissues and its regulation occurs through a complex mechanism that is essentially tissue specific.
Asunto(s)
Hidrocarburo de Aril Hidroxilasas/genética , Inhibidores Enzimáticos/farmacología , Metilcolantreno/farmacología , Oxigenasas de Función Mixta/genética , Norisoprenoides/farmacología , Pirazoles/farmacología , ARN Mensajero/metabolismo , Animales , Hidrocarburo de Aril Hidroxilasas/efectos de los fármacos , Citocromo P-450 CYP2A6 , Familia 2 del Citocromo P450 , Expresión Génica , Masculino , Oxigenasas de Función Mixta/efectos de los fármacos , Ratas , Ratas Wistar , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
Cytochrome P450 (CYP) 2A enzymes are involved in the metabolism of numerous drugs and hormones and activate different carcinogens. Human CYP2A6, mouse CYP2A5 and rat CYP2A3 are orthologous enzymes that present high similarity in their amino acid sequence and share substrate specificities. However, different from the human and mouse enzyme, CYP2A3 is not expressed in the rat liver. There are limited data about expression of CYP2A3 in extrahepatic tissues and its regulation by typical CYP inducers. Therefore, the objective of the present study was to analyze CYP2A3 mRNA expression in different rat tissues by RT-PCR, and to study the influence of 3-methylcholanthrene, pyrazole and ß-ionone treatment on its expression. Male Wistar rats were divided into four groups of 5 rats each, and were treated ip for 4 days with 3-methylcholanthrene (25 mg/kg body weight), pyrazole (150 mg/kg body weight), ß-ionone (1 g/kg body weight), or vehicle. Total RNA was extracted from tissues and CYP2A3 mRNA levels were analyzed by semiquantitative RT-PCR. CYP2A3 mRNA was constitutively expressed in the esophagus, lung and nasal epithelium, but not along the intestine, liver, or kidney. CYP2A3 mRNA levels were increased in the esophagus by treatment with 3-methylcholanthrene and pyrazole (17- and 7-fold, respectively), in lung by pyrazole and ß-ionone (3- and 4-fold, respectively, although not statistically significant), in the distal part of the intestine and kidney by 3-methylcholanthrene and pyrazole, and in the proximal part of the intestine by pyrazole. CYP2A3 mRNA was not induced in nasal epithelium, liver or in the middle part of the intestine. These data show that, in the rat, CYP2A3 is constitutively expressed in several extrahepatic tissues and its regulation occurs through a complex mechanism that is essentially tissue specific
Asunto(s)
Animales , Masculino , Ratas , Inhibidores Enzimáticos , Pirazoles , ARN Mensajero , Expresión Génica , Ratas Wistar , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
The association between alcohol consumption and esophageal cancer is particularly marked in Northern France where an apple brandy, Calvados, is drunk. Calvados contains branched chain alcohols such as isoamyl alcohol (IAA) and it has been suggested that these play a particular role in the etiology of the cancer. In this study the effect of IAA, alone or with ethanol, on the ethylation of DNA by N-nitrosodiethylamine was evaluated in living rats, and the effect of IAA on the metabolism of N-nitrosodiethylamine by rat liver microsomes or esophageal epithelium was measured. As previously reported co-administration of ethanol increases the ethylation of esophageal DNA by the nitrosamine by almost 2-fold, but IAA did not alter the proportion of DNA ethylation between liver and esophagus. When both alcohols were given together with the nitrosamine, the alteration on DNA ethylation produced by ethanol remained unchanged. Different from ethanol, IAA inhibited NDEA metabolism catalyzed not only by rat liver microsomes (K(i)=0.42 mM), but also by esophageal epithelium (K(i)=0.52 mM), thus possessing an affinity also for the esophageal NDEA metabolizing P450.
Asunto(s)
Carcinógenos/metabolismo , Carcinógenos/toxicidad , Depresores del Sistema Nervioso Central/toxicidad , ADN/efectos de los fármacos , Dietilnitrosamina/metabolismo , Dietilnitrosamina/toxicidad , Etanol/toxicidad , Pentanoles/toxicidad , Alquilación , Animales , ADN/genética , ADN/aislamiento & purificación , Esófago/metabolismo , Riñón/metabolismo , Cinética , Hígado/metabolismo , Masculino , Microsomas Hepáticos/efectos de los fármacos , Microsomas Hepáticos/metabolismo , Ratas , Ratas Sprague-DawleyRESUMEN
beta-myrcene (MYR) is an acyclic monoterpene found in the essential oils of several useful plants such as lemongrass (Cymbopogon citratus), hop, bay, verbena and others. Recently it has been reported that MYR as well as lemongrass oil blocked the metabolic activation of some promutagens (e.g., cyclophosphamide and aflatoxin B1) in in vitro genotoxicity assays. The present study was performed to evaluate the inhibitory effects of MYR and some other monoterpenoid compounds on microsomal enzymes involved in the activation of genotoxic substances. The effects of MYR and other monoterpenes on the activity of pentoxyresorufin-O-depenthylase (PROD), a selective marker for CYP2B1, was determined in a pool of liver microsomes prepared from phenobarbital-treated rats. The effect of MYR on the activity of ethoxyresorufin-O-deethylase (EROD), a marker for CYP4501A1, was investigated in liver microsomes of untreated rats. Results revealed that MYR had almost no effect on EROD (IC50 > 50 microM), but produced a concentration-dependent inhibition of PROD activity (IC50 =0.14 microM). The analysis of alterations produced by MYR on PROD kinetic parameters (Lineweaver-Burk plot) suggested that inhibition is competitive (Ki = 0.14 microM). The inhibitory effects of seven other monoterpenes on PROD activity (pentoxyresorufin 5 microM) were also studied and the IC50 were as follows: (-)-alpha-pinene, 0.087 microM; (+)-alpha-pinene, 0.089 microM; d-limonene, 0.19 microM; alpha-terpinene, 0.76 microM; citral, 1.19 microM; citronellal, 1.56 microM, and (+/-) camphor, 7.89 microM. The potent inhibitory effects on CYP4502B1 suggest that MYR, and other monoterpenes, interfere with the metabolism of xenobiotics which are substrates for this isoenzyme.
Asunto(s)
Citocromo P-450 CYP2B1/antagonistas & inhibidores , Aditivos Alimentarios/farmacología , Monoterpenos , Terpenos/farmacología , Monoterpenos Acíclicos , Animales , Citocromo P-450 CYP1A1/metabolismo , Citocromo P-450 CYP2B1/metabolismo , Inhibidores Enzimáticos , Femenino , Cinética , Microsomas Hepáticos/efectos de los fármacos , Microsomas Hepáticos/enzimología , Ratas , Ratas Wistar , Relación Estructura-ActividadRESUMEN
The high incidence of oesophageal cancer in Northern Iran has been associated with opium. N-Nitrosamines are the only carcinogens known to induce oesophageal cancer in animals. Ethanol, which is the major influence on oesophageal cancer incidence in the West, inhibits the first pass clearance of N-nitrosodimethylamine in animals and increases the alkylation of oesophageal DNA by oesophageal cancer-inducing N-nitrosamines. The experiments now reported were to test whether opium or morphine, which is the major alkaloid in opium, have a similar effect. It is shown that administration of morphine to rats does increase the ethylation of oesophageal DNA by N-nitrosodiethylamine and may reduce the first pass clearance of N-nitrosodimethylamine by the liver, but only at high doses of morphine.
Asunto(s)
Carcinógenos/metabolismo , Metilación de ADN , Dietilnitrosamina/metabolismo , Esófago/metabolismo , Morfina/farmacología , Narcóticos/farmacología , Opio/farmacología , Administración Oral , Animales , Carcinógenos/administración & dosificación , Dietilnitrosamina/administración & dosificación , Riñón/metabolismo , Hígado/metabolismo , Masculino , Microsomas Hepáticos/efectos de los fármacos , Microsomas Hepáticos/metabolismo , Ratas , Ratas Sprague-DawleyRESUMEN
Beta-Myrcene (MYR) is an acyclic monoterpene found in the essential oils of a variety of useful plants such as lemongrass (Cymbopogon citratus), hop, verbena, bay and others. MYR and essential oils containing this olefinic monoterpene are widely used as flavoring food additives, as fragrances in cosmetics and as scents in household products. The present study was undertaken to investigate the induction of liver monooxygenases by MYR. Female Wistar rats were treated by gavage with MYR (1000 mg/kg body weight) or corn oil (vehicle) for 1 or 3 consecutive days. Activities of ethoxycoumarin-O-deethylase (ECOD) and alkoxy-resorufin O-dealkylases (methoxy- (MROD), ethoxy- (EROD), pentoxy- (PROD) and benzyloxy-resorufin-O-dealkylation (BROD)) were determined fluorimetrically in the hepatic microsomal fraction. Exposure to MYR, either for 1 or 3 days, produced marked (13-34-fold) increases in the activities of PROD and BROD and only minor changes in ECOD, EROD and MROD. Since PROD and BROD are metabolized mainly by CYP2B isoenzymes, these results suggest that MYR induces this phenobarbital-inducible P450 subfamily. The induction of CYP2B isoenzymes was confirmed by SDS-PAGE and immunoblotting. Levels of apoproteins CYP2B1/2B2 were increased 8.2-fold after treatment with MYR (1000 mg/kg body wt, 3 days). Results from this study therefore indicate that MYR is an inducer of isoenzymes belonging to CYP2B subfamily.