RESUMO
The pregnane X receptor (PXR) is the key regulator of our defense mechanism against foreign substances such as drugs, dietary nutrients, or environmental pollutants. Because of increased health consciousness, the use of dietary supplements has gradually increased, and most of them can activate PXR. Therefore, an analysis of the interaction between drugs and nutrients is important because altered levels of drug-metabolizing enzymes or transporters can remarkably affect the efficiency of a co-administered drug. In the present study, we analyzed the effect of vitamin K-mediated PXR activation on drug metabolism-related gene expression in intestine-derived LS180 cells via gene expression studies and western blotting analyses. We demonstrated that menaquinone 4 (MK-4), along with other vitamin Ks, including vitamin K1, has the potential to induce MDR1 and CYP3A4 gene expression. We showed that PXR knockdown reversed MK-4-mediated stimulation of these genes, indicating the involvement of PXR in this effect. In addition, we showed that the expression of MDR1 and CYP3A4 genes increased synergistically after 24 h of rifampicin and MK-4 co-treatment. Our study thus elucidates the importance of drug-nutrient interaction mediated via PXR.
Assuntos
Citocromo P-450 CYP3A/efeitos dos fármacos , Expressão Gênica/efeitos dos fármacos , Receptor de Pregnano X/efeitos dos fármacos , Vitamina K/farmacologia , Subfamília B de Transportador de Cassetes de Ligação de ATP/efeitos dos fármacos , Carcinoma/tratamento farmacológico , Carcinoma/metabolismo , Linhagem Celular Tumoral , Humanos , Neoplasias Intestinais/tratamento farmacológico , Neoplasias Intestinais/metabolismo , Fenômenos Fisiológicos da Nutrição/genética , Rifampina/administração & dosagem , Vitamina K 1/farmacologia , Vitamina K 2/análogos & derivados , Vitamina K 2/farmacologiaRESUMO
SCOPE: The previous study shows that obesity-promoted inflammation is responsible for the activation of the intestinal tumorigenic Wnt-signaling. The present study aims to test a dietary strategy, dietary supplementation with a high dose of vitamin D (VD) or its combination with sulforaphane (SFN) to inhibit intestinal inflammation and obesity-associated tumorigenesis. METHODS AND RESULTS: Apc1638N mice are randomly divided into four groups: LF, a low-fat diet (10 kcal% fat) with 200 IU VD; HF, a high-fat diet (60 kcal% fat) with 200 IU VD; HFD, a high-fat diet with 5000 IU VD; and HFDS, a high-fat diet plus 5000 IU VD and 0.23 g SFN per ≈4000 kcal. VD administration decreased tumor incidence and size, and the co-administration with SFN (HFDS) magnified the effects. Inflammation and Wnt-signaling are suppressed by VD. The addition of SFN decreased the activity of histone deacetylase (HDAC) and increased autophagy. CONCLUSION: The administration of VD, at 5000 IU level, exerts an anti-inflammatory property and leads to suppressed intestinal Wnt-signaling and tumorigenesis in obese mice. The molecular function of SFN on a high dose of VD supplementation, although displayed on the inhibition of HDAC and the activation of autophagy, needs further investigation.
Assuntos
Antineoplásicos/farmacologia , Dieta Hiperlipídica/efeitos adversos , Neoplasias Intestinais/prevenção & controle , Isotiocianatos/farmacologia , Vitamina D/farmacologia , Animais , Anticarcinógenos/farmacologia , Autofagia/efeitos dos fármacos , Enterite/prevenção & controle , Feminino , Histona Desacetilases/metabolismo , Neoplasias Intestinais/metabolismo , Neoplasias Intestinais/patologia , Masculino , Camundongos Mutantes , Obesidade/complicações , Sulfóxidos , Vitamina D/análogos & derivados , Vitamina D/sangue , beta Catenina/metabolismoRESUMO
SCOPE: Evidence suggests that the dietary consumption of plant extracts containing polyphenols might help prevent the onset of cancers of the gastrointestinal tract. In the present study, the chemopreventive and antiproliferative efficacy of a grapevine shoot extract (Vineatrol®30) containing resveratrol and resveratrol oligomers is investigated in vivo and in vitro. METHODS AND RESULTS: The in vivo study is performed using ApcMin mice on a high-fat diet, which represents a model of human adenomatous polyposis, while the potential of the extract as well as some of its isolated constituents to inhibit intestinal adenoma cell proliferation in vitro is investigated using APC10.1 cells derived from an ApcMin mouse. Vineatrol®30 at a low (2.3 mg kg-1 diet) or high dose (476 mg kg-1 diet) reduces the adenoma number in male and adenoma volume in female animals. Furthermore, Vineatrol®30 as well as resveratrol and two resveratrol tetramers compromise the expansion of APC10.1 cells by reducing cell number, inducing cell cycle arrest, cellular senescence, and apoptosis. However, except for the extract, none of the isolated resveratrol oligomers is more efficacious than resveratrol in these cells. CONCLUSION: Vineatrol®30 may merit further investigation as a potential dietary gastrointestinal cancer chemopreventive agent in humans.
Assuntos
Adenoma/prevenção & controle , Anticarcinógenos/farmacologia , Neoplasias Intestinais/prevenção & controle , Fenóis/farmacologia , Resveratrol/farmacologia , Adenoma/metabolismo , Adenoma/patologia , Animais , Anticarcinógenos/química , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Caspases/metabolismo , Proliferação de Células/efeitos dos fármacos , Feminino , Neoplasias Intestinais/metabolismo , Neoplasias Intestinais/patologia , Masculino , Camundongos Mutantes , Fenóis/química , Resveratrol/química , Estilbenos/farmacologiaRESUMO
The role of folate one-carbon metabolism in colorectal cancer development is controversial, with nutritional intervention studies producing conflicting results. It has been reported that ApcMin/+ mice maintained on a diet deficient in the methyl donors folic acid, methionine, choline, and vitamin B12, and supplemented with homocysteine, show a greater than 95% reduction in intestinal tumor development. The present study extends these findings and shows that tumor protection afforded by dietary methyl donor deficiency (MDD) is long-lasting. After 11 weeks of MDD, tumor protection persisted for at least an additional 7 weeks of methyl donor repletion (22.2 ± 3.5 vs. 70.2 ± 4.6 tumors per mouse; P < 0.01). Sustained tumor protection was associated with a reduction in intestinal crypt length (26%, P < 0.01), crypt cell division and crypt fission, and an increase in apoptosis of both normal crypts and tumors (4.9- and 3.2-fold, respectively, P < 0.01). MDD also caused a significant reduction in the number of Dclk1-positive cells in the intestine (62%, P < 0.01), a long-lived crypt cell with cancer stem cell potential. Several undesirable effects associated with methyl donor restriction (e.g., reduced body weight gain) were shown to be transient and readily reversible following methyl donor repletion. Taken together, these results indicate that even temporary dietary methyl donor restriction in adenoma-prone mice can induce persistent changes to the intestinal epithelium and provide long-lasting tumor protection. These data also suggest that transient reductions in dietary methyl donor consumption should be considered when studying the impact of folate on colon cancer risk in humans. Cancer Prev Res; 9(10); 812-20. ©2016 AACR.
Assuntos
Adenoma/metabolismo , Dieta , Neoplasias Intestinais/metabolismo , Animais , Colina/metabolismo , Ácido Fólico/metabolismo , Metionina/deficiência , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Distribuição Aleatória , Vitamina B 12/metabolismoRESUMO
Therapeutic targeting of tumor angiogenesis with VEGF inhibitors results in demonstrable, but transitory efficacy in certain human tumors and mouse models of cancer, limited by unconventional forms of adaptive/evasive resistance. In one such mouse model, potent angiogenesis inhibitors elicit compartmental reorganization of cancer cells around remaining blood vessels. The glucose and lactate transporters GLUT1 and MCT4 are induced in distal hypoxic cells in a HIF1α-dependent fashion, indicative of glycolysis. Tumor cells proximal to blood vessels instead express the lactate transporter MCT1, and p-S6, the latter reflecting mTOR signaling. Normoxic cancer cells import and metabolize lactate, resulting in upregulation of mTOR signaling via glutamine metabolism enhanced by lactate catabolism. Thus, metabolic symbiosis is established in the face of angiogenesis inhibition, whereby hypoxic cancer cells import glucose and export lactate, while normoxic cells import and catabolize lactate. mTOR signaling inhibition disrupts this metabolic symbiosis, associated with upregulation of the glucose transporter GLUT2.
Assuntos
Inibidores da Angiogênese/uso terapêutico , Resistencia a Medicamentos Antineoplásicos , Neoplasias Intestinais/irrigação sanguínea , Neoplasias Intestinais/metabolismo , Tumores Neuroendócrinos/irrigação sanguínea , Tumores Neuroendócrinos/metabolismo , Neoplasias Pancreáticas/irrigação sanguínea , Neoplasias Pancreáticas/metabolismo , Transdução de Sinais , Neoplasias Gástricas/irrigação sanguínea , Neoplasias Gástricas/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Inibidores da Angiogênese/farmacologia , Animais , Axitinibe , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Glucose/metabolismo , Glutamina/metabolismo , Glicólise/efeitos dos fármacos , Humanos , Imidazóis/farmacologia , Imidazóis/uso terapêutico , Indazóis/farmacologia , Indazóis/uso terapêutico , Indóis/farmacologia , Indóis/uso terapêutico , Neoplasias Intestinais/tratamento farmacológico , Ácido Láctico/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Camundongos , Modelos Biológicos , Tumores Neuroendócrinos/tratamento farmacológico , Neoplasias Pancreáticas/tratamento farmacológico , Pirróis/farmacologia , Pirróis/uso terapêutico , Transdução de Sinais/efeitos dos fármacos , Sirolimo/farmacologia , Neoplasias Gástricas/tratamento farmacológico , Sunitinibe , Regulação para Cima/efeitos dos fármacosRESUMO
PURPOSE: Naringin is a natural dietary flavonoid compound. We aimed to evaluate the effects of naringin on intestinal tumorigenesis in the adenomatous polyposis coli multiple intestinal neoplasia (Apc (Min/+)) mouse model. METHODS: Apc (Min/+) mice were given either naringin (150 mg/kg) or vehicle by p.o. gavage daily for 12 consecutive weeks. Mice were killed with ether, and blood samples were collected to assess the concentrations of IL-6 and PGE2. Total intestines were removed, and the number of polyps was examined. Tissue samples of intestinal polyps were subjected to the assays of histopathology, immunohistochemical analysis and Western blotting analysis. RESULTS: Apc (Min/+) mice fed with naringin developed less and smaller polyps in total intestines. Naringin prevented intestinal tumorigenesis without adverse effects. Histopathologic analysis revealed the reduction of dysplastic cells and dysplasia in the adenomatous polyps. The treatments' effects might arise from its anti-proliferation, induction of apoptosis and modulation of GSK-3ß and APC/ß-catenin signaling pathways. Naringin also exerted its effects on tumorigenesis through anti-chronic inflammation. CONCLUSION: Naringin prevented intestinal tumorigenesis likely through a collection of activities including anti-proliferation, induction of apoptosis, modulation of GSK-3ß and APC/ß-catenin pathways and anti-inflammation. Naringin is a potential chemopreventive agent for reducing the risk of colonic cancers.
Assuntos
Transformação Celular Neoplásica/efeitos dos fármacos , Suplementos Nutricionais , Modelos Animais de Doenças , Flavanonas/farmacologia , Neoplasias Intestinais/prevenção & controle , Pólipos Intestinais/prevenção & controle , Proteína da Polipose Adenomatosa do Colo/fisiologia , Animais , Apoptose/efeitos dos fármacos , Western Blotting , Proliferação de Células/efeitos dos fármacos , Transformação Celular Neoplásica/metabolismo , Transformação Celular Neoplásica/patologia , Citocinas/metabolismo , Feminino , Humanos , Técnicas Imunoenzimáticas , Mediadores da Inflamação/metabolismo , Neoplasias Intestinais/metabolismo , Neoplasias Intestinais/patologia , Pólipos Intestinais/metabolismo , Pólipos Intestinais/patologia , Camundongos , Camundongos Endogâmicos C57BL , Células Tumorais CultivadasRESUMO
Mortality from colorectal cancer increases with latitude and decreases with ambient UV radiation. We investigated whether moderate UV dosages could inhibit intestinal tumor development and whether this corresponded with UV-induced vitamin D. FabplCre;Apc(15lox/+) mice, which develop intestinal tumors, and their parents were put on a vitamin D-deficient diet. Next to a control group, one group was vitamin D supplemented and another one group was daily UV irradiated from 6 weeks of age. Vitamin D statuses after 6 weeks of treatment were markedly increased: mean ± SD from 7.7 ± 1.9 in controls to 75 ± 15 nmol/l with vitamin D supplementation (no gender difference), and to 31 ± 13 nmol/l in males and 85 ± 17 nmol/l in females upon UV irradiation. The tumor load (area covered by tumors) at 7.5 months of age was significantly reduced in both the vitamin D-supplemented group (130 ± 25 mm(2), p = 0.018) and the UV-exposed group (88 ± 9 mm(2), p < 0.0005; no gender differences) compared to the control group (202 ± 23 mm(2)). No reductions in tumor numbers were found. Only UV exposure appeared to reduce progression to malignancy (p = 0.014). Our experiments clearly demonstrate for the first time an inhibitory effect of moderate UV exposure on outgrowth and malignant progression of primary intestinal tumors, which at least in part can be attributed to vitamin D.
Assuntos
Genes APC/fisiologia , Neoplasias Intestinais/patologia , Neoplasias Intestinais/prevenção & controle , Raios Ultravioleta , Vitamina D/administração & dosagem , Vitaminas/administração & dosagem , Animais , Suplementos Nutricionais , Progressão da Doença , Feminino , Neoplasias Intestinais/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BLRESUMO
Krüppel-like factor 4 (KLF4) is a zinc finger transcription factor that plays a vital role in regulating cell lineage differentiation during development and maintaining epithelial homeostasis in the intestine. In normal intestine, KLF4 is predominantly expressed in the differentiated epithelial cells. It has been identified as a tumor suppressor in colorectal cancer. KLF4 knockout mice demonstrated a decrease in number of goblet cells in the colon, and conditional ablation of KLF4 from the intestinal epithelium led to altered epithelial homeostasis. However, the role of KLF4 in differentiated intestinal cells and colon cancer cells, as well as the mechanism by which it regulates homeostasis and represses tumorigenesis in the intestine is not well understood. In our study, KLF4 was partially depleted in the differentiated intestinal epithelial cells by a tamoxifen-inducible Cre recombinase. We found a significant increase in the number of goblet cells in the KLF4-deleted small intestine, suggesting that KLF4 is not only required for goblet cell differentiation, but also required for maintaining goblet cell numbers through its function in inhibiting cell proliferation. The number and position of Paneth cells also changed. This is consistent with the KLF4 knockout study using villin-Cre [1]. Through immunohistochemistry (IHC) staining and statistical analysis, we found that a stem cell and/or tuft cell marker, DCAMKL1, and a proliferation marker, Ki67, are affected by KLF4 depletion, while an enteroendocrine cell marker, neurotensin (NT), was not affected. In addition, we found KLF4 depletion altered the morphology and polarity of the intestinal epithelial cells. Using a three-dimensional (3D) intestinal epithelial cyst formation assay, we found that KLF4 is essential for cell polarity and crypt-cyst formation in human colon cancer cells. These findings suggest that, as a tumor suppressor in colorectal cancer, KLF4 affects intestinal epithelial cell morphology by regulating proliferation, differentiation and polarity of the cells.
Assuntos
Células Epiteliais/citologia , Regulação Neoplásica da Expressão Gênica , Intestinos/citologia , Fatores de Transcrição Kruppel-Like/fisiologia , Animais , Células CACO-2 , Cromossomos Artificiais Bacterianos , Neoplasias do Colo/metabolismo , DNA Complementar/metabolismo , Homeostase , Humanos , Imuno-Histoquímica/métodos , Neoplasias Intestinais/metabolismo , Fator 4 Semelhante a Kruppel , Fatores de Transcrição Kruppel-Like/metabolismo , Camundongos , Camundongos Knockout , Camundongos TransgênicosRESUMO
Aloe vera is one of the most commonly used botanicals for various prophylactic and therapeutic purposes. Recently, NTP/NCTR has demonstrated a dose-dependent increase in large intestinal tumors in F344 rats chronically exposed to Aloe barbadensis Miller (Aloe vera) non-decolorized whole leaf extract (AVNWLE) in drinking water. The morphological and molecular pathways of AVNWLE-induced large intestinal tumors in the F344 rats were compared to human colorectal cancer (hCRC) literature. Defined histological criteria were used to compare AVNWLE-induced large intestinal tumors with hCRC. The commonly mutated genes (Kras, Ctnnb1, and Tp53) and altered signaling pathways (MAPK, WNT, and TGF-ß) important in hCRC were evaluated within AVNWLE-induced large intestinal tumors. Histological evaluation of the large intestinal tumors indicated eight of twelve adenomas (Ads) and four of twelve carcinomas (Cas). Mutation analysis of eight Ads and four Cas identified point mutations in exons 1 and 2 of the Kras gene (two of eight Ads, two of four Cas), and in exon 2 of the Ctnnb1 gene (three of eight Ads, one of four Cas). No Tp53 (exons 5-8) mutations were found in Ads or Cas. Molecular pathways important in hCRC such as MAPK, WNT, and TGF-ß signaling were also altered in AVNWLE-induced Ads and Cas. In conclusion, the AVNWLE-induced large intestinal tumors in F344 rats share several similarities with hCRC at the morphological and molecular levels.
Assuntos
Aloe/química , Neoplasias Colorretais/metabolismo , Neoplasias Intestinais/induzido quimicamente , Neoplasias Intestinais/metabolismo , Extratos Vegetais/toxicidade , Adenoma/induzido quimicamente , Adenoma/metabolismo , Adenoma/patologia , Animais , Biomarcadores Tumorais/metabolismo , Neoplasias Colorretais/patologia , Modelos Animais de Doenças , Histocitoquímica , Humanos , Neoplasias Intestinais/patologia , Intestino Grosso/patologia , Folhas de Planta/química , Análise de Componente Principal , Ratos , Ratos Endogâmicos F344 , Transdução de Sinais/efeitos dos fármacosRESUMO
PURPOSE: Red grape pomace extract (oenocyanin) is a cheap and rich source of anthocyanins, the agents suggested to possess cancer chemopreventive properties. Here the hypothesis was tested that oenocyanin added to the diet can interfere with intestinal adenoma development in the Apc(Min) mouse, a model of intestinal carcinogenesis linked to an Apc mutation. METHODS: Mice received oenocyanin (0.3%) in their diet until week 16, when adenoma number and burden were recorded. Expression of Akt and ERK proteins was studied by Western blot in adenomas to discover effects of anthocyanins on cellular signalling via the PI3 and MAP kinase pathways. Levels of anthocyanins were measured by HPLC with visible spectroscopic or mass spectrometric detection. RESULTS: In mice which had consumed oenocyanin, overall adenoma burden was halved and adenoma number was marginally reduced when compared with mice on control diet. The proliferation index in colonic adenomatous crypts, as reflected by Ki-67 staining, was significantly decreased from 88.14% in control mice to 75.6+/-4% in mice on oenocyanin (P=0.014). Expression of Akt in small intestinal adenomas from Apc(Min) mice on oenocyanin was reduced by 54% (P=0.003), when compared to controls. Oenocyanin anthocyanins and glucuronide metabolites were found in the urine and intestine but not in plasma. CONCLUSIONS: The results suggest that oenocyanin may be a viable and economical alternative to anthocyanin-rich berry extracts for chemopreventive intervention. Akt and pErk might be suitable biomarkers of anthocyanin target organ efficacy.
Assuntos
Adenoma/prevenção & controle , Antocianinas/análise , Antineoplásicos Fitogênicos/uso terapêutico , Neoplasias Intestinais/prevenção & controle , Fitoterapia/métodos , Vitis/química , Adenoma/metabolismo , Adenoma/patologia , Animais , Antocianinas/farmacocinética , Biomarcadores Tumorais/metabolismo , Proliferação de Células/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão/métodos , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos/métodos , Mucosa Intestinal/metabolismo , Neoplasias Intestinais/metabolismo , Neoplasias Intestinais/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Proteínas Proto-Oncogênicas c-akt/metabolismo , eIF-2 Quinase/metabolismoRESUMO
Most sporadic colorectal cancers (CRCs) develop through the adenoma-carcinoma sequence pathway and are initiated by adenomatous polyposis coli (APC) gene mutations. Estrogen receptor beta (ERbeta) is recognized to progressively reduce its expression in adenomatous and carcinomatous tissues in humans. Moreover, ERbeta deficiency enhances small intestinal tumorigenesis in rodents. In the Apc(Min/+) mouse model, we evaluated intestinal polyp development and ERbeta expression plus other biological parameters influencing tumor growth (epithelial cell proliferation, apoptosis and migration) following the addition of a combination of the ERbeta-selective agonist silymarin (SIL) and/or lignin (LIG) to a high-fat/low-fiber diet. Forty-five Apc(Min/+) mice were divided in four groups: animals fed on the tumorigenic high-fat/low-fiber diet, the tumorigenic diet supplemented with SIL (0.02%) or purified LIG (6.24%) or SIL (0.005%) + LIG (6.24%). In these animals, we assessed polyp number and volume and their degree of dysplasia together with ERbeta messenger RNA (mRNA) and protein levels and epithelial cell proliferation, migration and apoptosis. The latter group of parameters was evaluated in normal and adenomatous mucosa and the results compared with those found in wild-type (WT) mice fed on the control diet. The addition of SIL or LIG to the diet and even more the specific combination of the two significantly counteracted intestinal tumorigenesis and increased ERbeta mRNA and protein levels. Cell proliferation and apoptosis were rebalanced and cell migration accelerated, restoring values similar to those observed in WT animals. Our results further support a protective effect of ERbeta in CRC suggesting the use of the combination of SIL-LIG as a potential approach against CRC development.
Assuntos
Proteína da Polipose Adenomatosa do Colo/fisiologia , Dieta , Receptor beta de Estrogênio/metabolismo , Neoplasias Intestinais/metabolismo , Neoplasias Intestinais/patologia , Adenoma/etiologia , Adenoma/metabolismo , Adenoma/patologia , Animais , Apoptose , Western Blotting , Proliferação de Células , Modelos Animais de Doenças , Receptor beta de Estrogênio/genética , Técnicas Imunoenzimáticas , Marcação In Situ das Extremidades Cortadas , Neoplasias Intestinais/etiologia , Pólipos Intestinais/etiologia , Pólipos Intestinais/metabolismo , Pólipos Intestinais/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Regulação para CimaRESUMO
BACKGROUND: An inverse relationship between selenium (Se) intake and cancer mortality is evident in humans. MATERIALS AND METHODS: In eighty patients who had been operated on for primary gastric cancer, serum Se and carcinoembryonic antigen (CEA) levels were measured preoperatively using a fluorometric and immunoradiometric assay (IRMA), respectively. RESULTS: The serum Se levels were 43+/-6.3 microg l(-1) in the patient group and 68.7+/-4.5 microg l(-1) in healthy individuals (p<0.001). The serum CEA was 12+/-1.9 U ml(-1) in the gastric cancer patients and 2.1 U ml(-1) in the control group (p<0.001). The Se tissue concentrations were 2,640+/-220 mg g(-1) in excised neoplastic tissue and 685+/-115 mg g(-1) in non-neoplastic tissue (p<0.001). An inverse correlation between Se and CEA serum levels was found (r=-0.782). There was no correlation between serum/tissue Se concentration and disease stage/histological type or gender in the patient group.
Assuntos
Adenocarcinoma/metabolismo , Biomarcadores Tumorais/sangue , Antígeno Carcinoembrionário/sangue , Neoplasias Intestinais/metabolismo , Selênio/metabolismo , Neoplasias Gástricas/metabolismo , Adenocarcinoma/secundário , Estudos de Casos e Controles , Feminino , Fluorometria , Humanos , Técnicas Imunoenzimáticas , Ensaio Imunorradiométrico , Neoplasias Intestinais/patologia , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Neoplasias Gástricas/patologiaRESUMO
We investigated the possible mechanisms of inhibition of colorectal carcinogenesis by green tea (GT) in azoxymethane-treated (AOM) Apc(Min/+) mice. Mice received water or a 0.6% (w/v) solution of GT as the only source of beverage. GT treatment commenced at the 8th week of age and lasted for 8 wk. The treatment caused a statistically significant reduction in the number of newly formed tumors (28%, P < 0.05). Immunohistochemical analysis showed that GT decreased the levels of beta-catenin and its downstream target cyclin D1. To probe a mechanism, we further investigated the expression of retinoic X receptor alpha (RXR alpha) in AOM/Apc(Min/+) tumors. Our results show that RXR alpha is selectively downregulated in AOM/Apc(Min/+) mouse intestinal tumors. In contrast, other retinoic receptors including retinoic acid receptor alpha (RAR alpha), RAR beta, RXR beta, and RXR gamma were all expressed in Apc(Min/+) adenomas. Furthermore, our results show that RXR alpha downregulation is an early event in colorectal carcinogenesis and is independent of beta-catenin expression. GT significantly increased the protein levels of RXR alpha. In addition, RT-PCR analysis showed that GT induced a similar increase in the levels of RXR alpha mRNA. Genomic bisulfite treatment of colonic DNA followed by pyrosequencing of 24 CpG sites in the promoter region of RXR alpha gene showed a significant decrease in CpG methylation with GT treatment. The results suggest that a low concentration of GT is sufficient to desilence RXR alpha and inhibit intestinal tumorigenesis in the Apc(Min/+) mouse.
Assuntos
Adenoma/prevenção & controle , Modelos Animais de Doenças , Epigênese Genética/fisiologia , Genes APC/fisiologia , Neoplasias Intestinais/prevenção & controle , Receptor X Retinoide alfa/genética , Adenoma/induzido quimicamente , Adenoma/metabolismo , Adenoma/patologia , Animais , Azoximetano/toxicidade , Camellia sinensis , Carcinógenos/toxicidade , Ciclina D1/metabolismo , Metilação de DNA , Regulação para Baixo , Feminino , Técnicas Imunoenzimáticas , Neoplasias Intestinais/induzido quimicamente , Neoplasias Intestinais/metabolismo , Neoplasias Intestinais/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Regiões Promotoras Genéticas/genética , RNA Mensageiro/metabolismo , Receptor X Retinoide alfa/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Chá , beta Catenina/metabolismoRESUMO
Berries contain a number of compounds that are proposed to have anticarcinogenic properties. We studied the effects and molecular mechanisms of wild berries with different phenolic profiles on intestinal tumorigenesis in multiple intestinal neoplasia/+ mice. The mice were fed a high-fat AIN93-G diet (Con) or AIN93-G diets containing 10% (w:w) freeze-dried bilberry, lingonberry (LB), or cloudberry (CB) for 10 wk. All 3 berries significantly inhibited the formation of intestinal adenomas as indicated by a 15-30% reduction in tumor number (P < 0.05). CB and LB also reduced tumor burden by over 60% (P < 0.05). Compared to Con, CB and LB resulted in a larger (P < 0.05) proportion of small adenomas (43, 69, and 64%, respectively) and a smaller proportion of large adenomas (56, 29, and 33%, respectively). Beta-catenin and cyclin D1 in the small and large adenomas and in the normal-appearing mucosa were measured by Western blotting and immunohistochemistry. CB resulted in decreased levels of nuclear beta-catenin and cyclin D1 and LB in the level of cyclin D1 in the large adenomas (P < 0.05). Early changes in gene expression in the normal-appearing mucosa were analyzed by Affymetrix microarrays, which revealed changes in genes implicated in colon carcinogenesis, including the decreased expression of the adenosine deaminase, ecto-5'-nucleotidase, and prostaglandin E2 receptor subtype EP4. Our results indicate that berries are potentially a rich source of chemopreventive components.
Assuntos
Transformação Celular Neoplásica/efeitos dos fármacos , Frutas/química , Neoplasias Intestinais/prevenção & controle , Rosaceae/química , Transdução de Sinais/efeitos dos fármacos , Vaccinium/química , beta Catenina/metabolismo , Proteína da Polipose Adenomatosa do Colo/genética , Proteína da Polipose Adenomatosa do Colo/metabolismo , Animais , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Caderinas/genética , Caderinas/metabolismo , Ciclina D1/genética , Ciclina D1/metabolismo , Dieta , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Neoplasias Intestinais/tratamento farmacológico , Neoplasias Intestinais/metabolismo , Neoplasias Intestinais/patologia , Camundongos , Camundongos Mutantes , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Transcrição GênicaRESUMO
INTRODUCTION: The American Cancer Society estimated that more than 1 million new cancer cases were diagnosed in 2005 and a majority of these patients died from metastatic spread. The standard for treating solid tumor cancer is surgical resection. However, it has been suggested that surgical resection may, in fact, promote metastasis. One of the body's natural defenses to combat metastasis is the activity of natural killer (NK) cells. NK cells serve as a vital mediator of detection during the early innate immune response and destruction of aberrant cells. It has been demonstrated that benzodiazepines may ameliorate surgery-induced suppression of NK cell activity. We examined the effect of a 14-day course of valerian, a herbal anxiolytic, on NK cell activity in Sprague-Dawley rats. METHODS: Thirty-five rats were assigned to 1 of 3 groups: (1) surgical animals administered research grade valerian, 15 mg/kg solubilized in peanut oil; (2) surgical animals administered peanut oil (vehicle); and (3) anesthesia-only animals administered valerian. One day before the 14-day course of valerian, blood was drawn to assay baseline NK cell activity. On experimental day, all animals were administered isoflurane anesthesia. Surgical animals underwent a standard laparotomy whereas anesthesia-only rats were anesthetized for the same period of time as the surgical rats. Twenty-four hours postexperiment animals underwent a second blood draw to assay NK cell activity. RESULTS: Analysis of covariance (ANCOVA) was used to analyze NK cell activity (measured in lytic units). Our results suggested that there was no difference (P = .9) in suppression within or between groups. CONCLUSIONS: Clinical studies with valerian have been published but with small numbers and some ambiguity. Further research regarding valerian's effectiveness as a modulator of NK cell activity and whether dosage or route of administration is a factor in modulation is still warranted.
Assuntos
Células Matadoras Naturais/efeitos dos fármacos , Laparotomia/efeitos adversos , Fitoterapia/métodos , Pré-Medicação/métodos , Cuidados Pré-Operatórios/métodos , Valeriana , Análise de Variância , Animais , Ansiedade/etiologia , Ansiedade/metabolismo , Ansiedade/prevenção & controle , Modelos Animais de Doenças , Esquema de Medicação , Avaliação Pré-Clínica de Medicamentos , Imunidade Celular , Inflamação , Neoplasias Intestinais/imunologia , Neoplasias Intestinais/metabolismo , Neoplasias Intestinais/cirurgia , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Masculino , Inoculação de Neoplasia , Ratos , Ratos Sprague-Dawley , Fatores de TempoRESUMO
To sustain growth and support metabolic requirements, mammals assimilate energy-producing molecules and nutrients from food. These molecules are distributed throughout the body in order to meet the requirements of the internal organs. The various demands of the different organs are to a large extent met by regulatory processes consisting of a complex interaction between hormones, growth factors and cytokines. Normal metabolic activity and partitioning of nutrients between individual organs is affected by a number of events such as stress, a limited supply of nutrients, infection or tumour growth. Since the intestine has the highest metabolic activity of all the internal organs, a tumour will initially compete with the gut for nutrients and energy-providing molecules. The polyamines represent a class of molecules where the demand in the body increases during tumour growth. A tumour can partly obtain the polyamines required to support its growth by up-regulating its own biosynthetic capacity and partly by increasing uptake from the body pool. Rather than limiting the exogenous supply of dietary polyamines we have used another approach to manipulate polyamine pools in mice. When the lectin phytohaemagglutinin is included in the diet, a fully reversible dose-dependent growth of the small intestine occurs leading to an extensive accumulation of polyamines in the intestinal epithelia. This approach of reducing the availability of exogenous polyamines to a growing tumour will be discussed.
Assuntos
Neoplasias Intestinais/metabolismo , Neoplasias Intestinais/patologia , Fito-Hemaglutininas/uso terapêutico , Poliaminas/metabolismo , Ração Animal , Animais , Disponibilidade Biológica , Suplementos Nutricionais , Modelos Animais de Doenças , Fabaceae , Humanos , Hiperplasia , Mucosa Intestinal/metabolismo , Neoplasias Intestinais/prevenção & controleRESUMO
Arginine is catabolized by NOS2 and other nitric oxide synthases to form nitric oxide. We evaluated the roles of dietary arginine and Nos2 in Apc-dependent intestinal tumorigenesis in Min mice with and without a functional Nos2 gene. NOS2 protein was expressed only in intestinal tissues of Apc(Min/+) Nos2+/+ mice. NOS3 expression was higher in intestinal tissues of mice lacking Nos2, mainly in the small intestine. When diet was supplemented with arginine (0.2% and 2% in drinking water), lack of Nos2 results in decreased tumorigenesis in both small intestine and colon. In Nos2 knockout mice, supplemental arginine (up to 2%) caused a decrease in small intestinal tumor number and size. The arginine-dependent decrease was associated with an increase in nitrotyrosine formation and apoptosis in the region of intestinal stem cells. Mice expressing Nos2 did not show these changes. These mice did, however, show an arginine-dependent increase in colon tumor number and incidence, while no effect on apoptosis was seen. These changes were associated with increased nitrotyrosine formation in epithelial cells. Mice lacking Nos2 did not show changes in tumorigenesis or nitrotyrosine formation, while demonstrating an arginine-dependent increase in apoptosis. These data suggest that Nos2 and dietary arginine have significant effects on intestinal and colonic tumorigenesis in Min mice. In both tissues, loss of Nos2 is associated with decreased tumorigenesis when mice are supplemented with dietary arginine. In the small intestine, Nos2 prevents the arginine-induced decrease in tumor number and size, which is associated with NOS3 expression and increased apoptosis. In the colon, Nos2 is required for the arginine-induced increase in tumor number and incidence.
Assuntos
Arginina/farmacologia , Neoplasias do Colo/enzimologia , Neoplasias Intestinais/enzimologia , Intestino Delgado/patologia , Óxido Nítrico Sintase Tipo II/metabolismo , Proteína da Polipose Adenomatosa do Colo/genética , Proteína da Polipose Adenomatosa do Colo/metabolismo , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Arginina/metabolismo , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Suplementos Nutricionais , Feminino , Neoplasias Intestinais/metabolismo , Neoplasias Intestinais/patologia , Intestino Delgado/efeitos dos fármacos , Masculino , Camundongos , Camundongos Knockout , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo III/efeitos dos fármacos , Óxido Nítrico Sintase Tipo III/genética , Óxido Nítrico Sintase Tipo III/metabolismo , Tirosina/análogos & derivados , Tirosina/metabolismoRESUMO
Flaxseed is a dietary source of possible chemopreventive compounds such as lignans and alpha-linolenic acid (ALA). To study the effects of a flaxseed mixture on adenoma formation in multiple intestinal neoplasia mice, the mice were fed a diet containing 2.7 % flaxseed, 4.5 % fibre and 3.7 % ALA. To elucidate the effect of oils of the mixture we also composed a diet without flaxseed but with the same oil composition. The median number of adenomas in the small intestine was fifty-four for the control group, and thirty-seven (P=0.023) and forty-two (P=0.095) for flaxseed and oil groups, respectively. Compared with controls (1.2 mm), the adenoma size was smaller in the flaxseed (0.9 mm; P=0.002) and oil (1.0 mm; P=0.012) groups. Both diets changed the proportions of n-3 and n-6 fatty acids in the colonic mucosa. Membrane beta-catenin and protein kinase C (PKC)-zeta levels were reduced in the adenoma v. mucosa (P<0.05), and an inverse association was found between the membrane PKC-zeta in the mucosa and the adenoma number (r -0.460, P=0.008, n 32). Only the flaxseed diet increased lignan levels in the caecum (P=0.002) and in plasma (P=0.002) but they were not associated with tumour formation. The results suggest that the preventive effect of flaxseed on colon carcinogenesis may be due to the oil part of flaxseed, and the loss of beta-catenin and PKC-zeta from the membranes of the mucosal tissue may play a permissive role in intestinal tumour development.
Assuntos
Adenoma/prevenção & controle , Linho , Neoplasias Intestinais/prevenção & controle , Neoplasias Primárias Múltiplas/prevenção & controle , Óleos de Plantas/administração & dosagem , Ácido alfa-Linolênico/administração & dosagem , Actinas/análise , Adenoma/metabolismo , Animais , Western Blotting/métodos , Colo/química , Ciclo-Oxigenase 2/análise , Ácidos Graxos/análise , Mucosa Intestinal/química , Neoplasias Intestinais/metabolismo , Lignanas/metabolismo , Óleo de Semente do Linho/metabolismo , Camundongos , Camundongos Mutantes , Modelos Animais , Neoplasias Primárias Múltiplas/metabolismo , Proteína Quinase C/análise , Aumento de Peso , beta Catenina/análiseRESUMO
BACKGROUND & AIM: The mammalian lignan enterolactone (ENL) produced from plant lignans, e. g. secoisolariciresinol diglycoside (SDG), may protect against various cancers in humans. The present work aims to evaluate the effect of flaxseed on tumour formation in multiple intestinal neoplasia (Min) mice, a model for colon tumorigenesis. DESIGN: Male and female Min mice were fed either with a non-fibre control diet or the same diet supplemented with 0.5 % (w/w) defatted flaxseed meal. Conversion of SDG to the mammalian lignans enterodiol (END) and ENL in the gut, and plasma ENL, were measured by HPLC with coulometric electrode array detector (CEAD) and timeresolved fluoroimmunoassay, respectively. Wild-type mice were also fed with the experimental diets in order to see whether lignan metabolism is different in Min and wild-type mice. RESULTS: The total number of adenomas or their size in the small intestine was not different in the flaxseed and control groups. The flaxseed group had a tendency for a decreased number of colon adenomas in both genders. Gender and genotype based differences were found in the intestinal ENL levels. When compared to Min females, Min males in the flaxseed group had several fold higher ENL levels in the small intestine (Min males 125 +/- 124.5 nmol/g vs. females 22.8 +/- 16.0 nmol/g, P = 0.048) and caecum (47.6 +/- 31.6 nmol/g vs. females 14.5 +/- 6.6 nmol/g, P = 0.001). Presence of adenomas in the gut influences the intestinal lignan metabolism. Min mice had less intestinal END and ENL as compared with the wild-type mice (P < 0.05). Mean plasma ENL increased 7-fold during the flaxseed feeding (7 nmol/L in control vs. 50 nmol/L in flaxseed group) but no differences between gender and genotype were found. The plasma ENL level did not correlate with adenoma number in the small intestine and colon. CONCLUSION: The number of intestinal adenomas in the Min mouse model is not related to ENL level in plasma nor is it associated with the levels of intestinal lignans. A gender difference in ENL lignan metabolism was found in the gut but not in the plasma.
Assuntos
Adenoma/prevenção & controle , Linho , Neoplasias Intestinais/prevenção & controle , Lignanas/farmacologia , Fitoestrógenos/farmacologia , Adenoma/genética , Adenoma/metabolismo , Animais , Cromatografia Líquida de Alta Pressão , Modelos Animais de Doenças , Feminino , Fluorimunoensaio , Genótipo , Neoplasias Intestinais/genética , Neoplasias Intestinais/metabolismo , Lignanas/metabolismo , Masculino , Camundongos , Camundongos Mutantes , Neoplasias Primárias Múltiplas/genética , Neoplasias Primárias Múltiplas/metabolismo , Neoplasias Primárias Múltiplas/prevenção & controle , Distribuição Aleatória , Fatores SexuaisRESUMO
The effects of vitamin deficiency on intestinal cancer are unclear, and even less is known about the consequences of excessive intake. We therefore investigated the actions of altered vitamin content on intestinal polyp development, cell proliferation and crypt fission in a mouse model of neoplasia. Ninety multiple intestinal neoplasia (ApcMin/+) mice and 90 wild-type littermates, 4 weeks old, were divided into six groups and fed either a control semi-synthetic diet, or the semi-synthetic diet with the vitamin content lowered to a third of the RDA or the semi-synthetic diet with the vitamin content increased 5-fold (except for retinol and folate, which were doubled). The number and size of polyps in the small and large intestines were scored after 8 weeks on the diets, as was cell proliferation (native mitoses per crypt) and crypt fission. The small intestines of the low and high vitamin groups were heavier than the controls. There were significantly more polyps and the tumour burden was higher in both the low and the high vitamin groups (P < 0.02). Proliferation was slightly reduced by the vitamin alteration and crypt fission was significantly increased in the ApcMin/+ mice when compared with the wild-type (P < 0.001). Fission indices were decreased by vitamin alteration in the small intestine, and increased in the colon, but only in the ApcMin/+ mice. The effects of vitamin alteration on polyp number were most pronounced in the proximal intestine, which is also the site of maximum crypt fission. Both vitamin deficiency and over-supplementation can markedly enhance polyp number and tumour burden.