RESUMEN
During rat hepatocarcinogenesis preneoplastic lesions (PNL) emerge which may persist (pPNL) and be sites of progress to cancer or suffer remodeling (rPNL) tending to disappear. Cellular and molecular mechanisms involved in both phenotypes are not sufficiently elucidated. pPNL and rPNL cellular proliferation and apoptosis were evaluated in rats submitted to the resistant hepatocyte (RH) model, and an adjusted growth index (AGI) was established. p53, Bcl-2, and NF-kappaB p65 subunit expression was evaluated by immunohistochemistry in pPNL and rPNL. p65 expression and NF-kappaB activation was evaluated by Western blot assays in whole livers. A lower number of BrdU-stained hepatocyte nuclei/mm(2) and higher number of apoptotic bodies (AB) per mm(2) were observed in remodeling compared to pPNL. Cytoplasmic p53 accumulation is related to increased hepatocarcinoma malignancy. We observed that 71.3% pPNL and 25.4% rPNL (P < 0.05) presented p53 staining in the cytoplasm. Similarly, 67.7% pPNL and 23.1 % rPNL (P < 0.05) presented increased Bcl-2 staining. Thirty-two percent pPNL and 15.6% rPNL (P < 0.05) presented p65 staining. Compared to normal rats, increase (P < 0.05) of hepatic p65 expression and NF-kappaB activation in rats submitted to the RH model was observed. In agreement to previous studies hepatic pPNL and rPNL differ regarding cell proliferation and apoptosis. Moreover, persistence and remodeling involve differences in p53, Bcl-2, and NF-kappaB pathways. These data point to molecular pathways that may direct preneoplastic lesions to spontaneously regress or to progress to cancer. J. Cell. Biochem. 103: 538-546, 2008. (c) 2007 Wiley-Liss, Inc.
Asunto(s)
Hepatopatías/patología , Neoplasias Hepáticas Experimentales/patología , FN-kappa B/fisiología , Lesiones Precancerosas/patología , Proteínas Proto-Oncogénicas c-bcl-2/fisiología , Factor de Transcripción ReIA/fisiología , Proteína p53 Supresora de Tumor/fisiología , 2-Acetilaminofluoreno/toxicidad , Animales , Apoptosis , Enfermedad Hepática Inducida por Sustancias y Drogas , Cocarcinogénesis , Replicación del ADN , Dietilnitrosamina/toxicidad , Progresión de la Enfermedad , Regulación de la Expresión Génica , Hepatectomía/métodos , Hepatocitos/metabolismo , Hepatocitos/patología , Hepatopatías/genética , Hepatopatías/metabolismo , Neoplasias Hepáticas Experimentales/inducido químicamente , Neoplasias Hepáticas Experimentales/genética , Regeneración Hepática , Masculino , Lesiones Precancerosas/inducido químicamente , Lesiones Precancerosas/genética , Lesiones Precancerosas/metabolismo , Distribución Aleatoria , Ratas , Ratas Endogámicas F344RESUMEN
Chemopreventive activities of all-trans retinoic acid (AtRA), 9-cis retinoic acid (9cRA), retinol (ROL) and beta-carotene (betaC) were evaluated during hepatocarcinogenesis. Rats received 1 mg/100 g body wt AtRA (AtRA group), 9cRA (9cRA group), ROL (ROL group), 7 mg/100 g body wt betaC (betaC group) or corn oil (CO group, controls). Hepatocyte nodule incidence was reduced (P < 0.05) in betaC group (46%), but not (P > 0.05) in AtRA (92%), 9cRA (92%) and ROL (82%) groups, compared with the CO group (100%). Multiplicity of these preneoplastic lesions (PNL) was different (P < 0.05) between CO group (44 +/- 9) and 9cRA (11 +/- 4), ROL (7 +/- 3) and betaC (4 +/- 2) groups, except for AtRA group (27 +/- 9; P > 0.05). Number/cm(2) liver section, mean area (mm(2)) and percent liver section area occupied by total (persistent + remodeling) placental glutathione S-transferase (GST-P) positive PNL was reduced (P < 0.05) in AtRA (107 +/- 13; 0.12 +/- 0.06; 13.9 +/- 3.9), 9cRA (71 +/- 12; 0.12 +/- 0.06; 6.8 +/- 2.2), ROL (96 +/- 13; 0.11 +/- 0.22; 6.8 +/- 2.0) and betaC (106 +/- 13; 0.08 +/- 0.03; 10.8 +/- 2.5) groups compared with CO group (166 +/- 14; 0.18 +/- 0.09; 28.6 +/- 5.2). Percent of remodeling GST-P positive PNL was increased (P < 0.05) in 9cRA (92 +/- 1), ROL (96 +/- 1) and betaC (93 +/- 1) groups, but not (P > 0.05) in AtRA group (90 +/- 2), compared with the CO group (86 +/- 1). Compared with the CO group, all groups present in PNL reduced (P < 0.05) cell proliferation and no differences (P > 0.05) in apoptosis. DNA damage [comet length (mum)] was reduced (P < 0.05) in ROL (87.9 +/- 2.6) and betaC (89.2 +/- 4.0) groups, but not in AtRA (94.8 +/- 4.1) and 9cRA (94.2 +/- 1.5) groups, compared with the CO group (100.4 +/- 3.9). AtRA, 9cRA, ROL and betaC presented chemopreventive activities against hepatocarcinogenesis. These involve inhibition of cell proliferation, but not induction of apoptosis. Increased remodeling of GST-P positive PNL relates to 9cRA, ROL and betaC actions, while inhibition of DNA damage relates to ROL and betaC actions.
Asunto(s)
Antineoplásicos/farmacología , Quimioprevención , Daño del ADN/efectos de los fármacos , Glutatión Transferasa/metabolismo , Neoplasias Hepáticas Experimentales/prevención & control , Lesiones Precancerosas/prevención & control , beta Caroteno/farmacología , Alitretinoína , Animales , Antioxidantes/farmacología , Apoptosis/efectos de los fármacos , Peso Corporal/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Ensayo Cometa , Hepatocitos/citología , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Incidencia , Neoplasias Hepáticas Experimentales/enzimología , Neoplasias Hepáticas Experimentales/patología , Masculino , Tamaño de los Órganos/efectos de los fármacos , Lesiones Precancerosas/enzimología , Lesiones Precancerosas/patología , Ratas , Ratas Wistar , Tretinoina/farmacología , Vitamina A/farmacologíaRESUMEN
Chemopreventive activities of the isoprenoids geranylgeraniol (GGO) and beta-ionone (BI) were evaluated during initial phases of hepatocarcinogenesis. Rats received 8 or 16 mg/100 g body wt GGO (GGO8 and GGO16 groups) or BI (BI8 and BI16 groups), or only corn oil (CO group, controls) daily for 7 weeks. Incidence (%) and the mean number of visible hepatocyte nodules/animal were inhibited in the GGO8 (64% and 21 +/- 40), GGO16 (33% and 3 +/- 5), BI8 (50% and 13 +/- 34) and BI16 (42% and 9 +/- 19) groups compared with the CO group (100% and 34 +/- 51) (P < 0.05, except for the GGO8 group). Number/cm(2) liver section, mean area (mm(2)) and % liver section area occupied by persistent hepatic placental glutathione S-transferase positive preneoplastic lesions (PNL) were reduced in the GGO8 (11 +/- 9; 0.26 +/- 0.35; 2.7 +/- 3.0), GGO16 (6 +/- 6; 0.18 +/- 0.16; 0.9 +/- 0.9), BI8 (9 +/- 5; 0.13 +/- 0.20; 1.1 +/- 1.2) and BI16 (8 +/- 6; 0.08 +/- 0.09; 0.6 +/- 0.4) groups compared with the CO group (26 +/- 18; 0.29 +/- 0.34; 7.0 +/- 5.5) (P < 0.05). GGO16 and BI16 groups showed smaller visible hepatocyte nodules, reduced PNL cell proliferation and total plasma cholesterol levels compared with the CO group (P < 0.05), but did not show any differences (P > 0.05) in PNL apoptosis. DNA damage expressed as comet length (microm) was reduced in the GGO8 (96.7 +/- 1.5), GGO16 (94.2 +/- 1.5), BI8 (97.1 +/- 1.1) and BI16 (95.1 +/- 1.5) groups compared with the CO group (102.1 +/- 1.7) (P < 0.05). In comparison with normal animals, the CO group animals showed increased (P < 0.05) nuclear levels of nuclear factor kappa B (NF-kappaB) p65 subunit in hepatic cells, which were decreased (P < 0.05) in the GGO16 group animals. Anticarcinogenic actions of these isoprenoids seem to follow a dose-response relationship. Results indicate that GGO and BI could be represented as promising chemopreventive agents against hepatocarcinogenesis. Inhibition of cell proliferation and DNA damage seems to be important for the anticarcinogenic actions of isoprenoids, while the inhibition of NF-kappaB activation seems to be specifically related to GGO actions.
Asunto(s)
Anticarcinógenos/farmacología , Colesterol/sangre , Daño del ADN/efectos de los fármacos , Diterpenos/farmacología , Neoplasias Hepáticas Experimentales/prevención & control , FN-kappa B/antagonistas & inhibidores , Norisoprenoides/farmacología , Animales , Apoptosis/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Aceite de Maíz , Activación Enzimática/efectos de los fármacos , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Neoplasias Hepáticas Experimentales/patología , Masculino , FN-kappa B/metabolismo , Lesiones Precancerosas/patología , Lesiones Precancerosas/prevención & control , Ratas , Ratas Wistar , Factor de Transcripción ReIARESUMEN
Avaliou-se os efeitos dos ácidos oleanólico (AO) e ursólico (AU), triterpenóides presentes em alimentos vegetais e especiarias, quando administrados a ratos F344 durante as etapas de iniciação e seleção/promoção do modelo de hepatocarcinogênese do ®hepatócito resistente¼ (RH). Os ratos receberam durante 8 semanas, por entubação gástrica e dissolvido em óleo de milho (OM): AO ou AU (8 mg/100 g de peso corpóreo [p.c]). Os grupos controle receberam apenas OM (0,25 mL/100 g de p.c; grupo OM), ou água (0,25 mL/100 g de p.c; grupo Água). O grupo Normal não recebeu qualquer tratamento. O agente iniciante foi uma dose de dietilnitrosamina (DEN, 20 mg/100 g de p.c.). Após 2 semanas de entubação, aplicou-se 3 doses diárias consecutivas de 2-acetilaminofluoreno (2-AAF)(2 mg/100 g de p.c.) e fez-se uma hepatectomia parcial a 70 por cento, acrescida de 1 dose de 2-AAF (0,5 mg/100 g de p.c.) 4 dias após a cirurgia...
It was evaluated the effects of the oleanólico acid (OA) and ursolic acid (UA), triterpenoids present in vegetable foods and spices, when administered to rat F344 during the initiation and selection/promotion stages of the resistant hepatocyte model of hepatocarcinogenesis RH. The rat received for 8 weeks, by gavage and dissolved in com oil (CO): OA or UA (8 mg/100 g of body weight [b.w.]). The control groups just received CO (0,25 mL/100 g b.w.; CO group), or water (0,25 mL/100 g b.w.; group Water). Normal group did not receive any treatment type. The initiation agent was dietilnitrosamine (DEN, 20 mg/100 g b.w.). 2 weeks after gavage, it was applied 3 consecutive doses of 2-acetilaminofluoreno (2-AAF) (2 mg/100 g of b.w.) and it was made a 70% partial hepatectomy, added of 1 dose of 2-AAF (0,5 mg/100 9 b.w.) 4 days after the surgery. In 6 weeks after the initiation, the animals were sacrificed. Results: the macroscopic analysis demonstrated that OA did not alter and UA tended to increase the number of hepatocytes nodules, compared to the CO group. The morphometric analysis of the pre-neoplastic lesions (PNL) positive for glutatione S-transferase placentary form (GST-p), demonstrated that OA and UA did not alter the medium number of persistent LPN, however they reduced the medium number of remodeling LPN, compared to the OM group (p <0,05). OA and UA did not alter the medium area of persistent LPN, but they reduced the medium area of remodeling LPN, compared to the CO group (p <0,05). The triterpenoids did not alter the occupied area of the section for persistent LPN, but they reduced the occupied area cut for remodeling LPN, compared to the CO group (p <0,05). The Water, OM and AU groups showed increase in the plasmatic concentration of cholesterol, compared to the Normal group. OA promoted increase of the expression of the gene that codifies for the HMG-CoA reductase enzyme, compared to the Normal group (p <0,05), and AU promoted increase expression when compared to the Normal, Water, OM and AU groups (p <0,05). OA and UA did not alter the indexes of cellular proliferation (imunoistochemistry for bromodeoxiuridine [BrdU)) in persistent LPN. AU promoted increase (p <0,05) in the cellular proliferation in remodeling LPN when compared to the CO group. OA and UA did not alter the apoptosis in persistent LPN, but they increased the medium number of apoptotics bodies in remodeling LPN (p <0,05). The Adjusted Index Growth (cellular apoptosis/proliferation) of the groups demonstrated that, in persistent LPN, the cellular proliferation has predominance on the apoptosis. In remodeling LPN, the apoptosis has preponderance over the cellular proliferation. The damages in hepatic DNA (method of the "comet") were larger in the group OA (p <0,05) and AU (p <0,061), compared to the CO group. The analysis for imunoblot revealed that the RH model increased the expression and the activation of the NF-κB transcription factor (p <0,05). OA and UA increased the expression and the activation of NF-κB, compared to the CO group (p> 0,05). It was...
Asunto(s)
Animales , Ratas , Quimioprevención , Hidroximetilglutaril-CoA Reductasas , Ácido Oleanólico , Plantas , Especias , Triterpenos , Daño del ADN , FN-kappa B , Ciencias de la NutriciónRESUMEN
Diversos autores relataram os efeitos do césio não radioativo sobre o câncer, que se mostrou efetivo na diminuição da incidência de neoplasias em modelos experimentais. Estudos em humanos em estado terminal mostraram 50 por cento de cura. Em algumas localidades onde a concentração de césio no solo é elevada e as populações se alimentam de plantações ali feitas, a incidência de câncer é baixa. Este estudo mostra a necessidade de mais pesquisas sobre os efeitos antineoplásicos do césio, baseadas nos recentes avanços técnicos e teóricos sobre o câncer.