Preventive Effects of (−)-Epigallocatechin Gallate on Diethylnitrosamine-Induced Liver Tumorigenesis in Obese and Diabetic C57BL/KsJ-db/db Mice
| Autor: | Masaya Kubota, Hisataka Moriwaki, Masahito Shimizu, Yohei Shirakami, Tomohiko Ohno, Hiroyasu Sakai, Daishi Terakura, Yukihiko Hara, Atsushi Baba, Yoichi Yasuda, Takuji Tanaka |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
Adenoma
Male MAPK/ERK pathway Cancer Research medicine.medical_specialty medicine.medical_treatment Fatty Acids Nonesterified Epigallocatechin gallate Biology complex mixtures Catechin Diabetes Mellitus Experimental Receptor IGF Type 1 Mice chemistry.chemical_compound Insulin resistance Internal medicine medicine Hyperinsulinemia Animals Anticarcinogenic Agents Diethylnitrosamine Obesity Extracellular Signal-Regulated MAP Kinases Glycogen synthase Protein kinase B Kinase Insulin Liver Neoplasms food and beverages medicine.disease Mice Inbred C57BL Endocrinology Liver Oncology chemistry Carcinogens biology.protein Proto-Oncogene Proteins c-akt |
| Zdroj: | Cancer Prevention Research. 4:396-403 |
| ISSN: | 1940-6215 1940-6207 |
| Popis: | Obesity and related metabolic abnormalities, including insulin resistance and a state of chronic inflammation, increase the risk of hepatocellular carcinoma. Abnormal activation of the insulin-like growth factor (IGF)/ IGF-1 receptor (IGF-1R) axis is also involved in obesity-related liver tumorigenesis. In the present study, we examined the effects of (−)-epigallocatechin gallate (EGCG), a major biologically active component of green tea, on the development of diethylnitrosamine (DEN)-induced liver tumorigenesis in C57BL/KsJ-db/db (db/db) obese mice. Male db/db mice were given tap water containing 40 ppm DEN for 2 weeks and then they received drinking water containing 0.1% EGCG for 34 weeks. At sacrifice, drinking water with EGCG significantly inhibited the development of liver cell adenomas in comparison with the control EGCG-untreated group. EGCG inhibited the phosphorylation of the IGF-1R, ERK (extracellular signal-regulated kinase), Akt, GSK-3β (glycogen synthase kinase-3β), Stat3, and JNK (c-Jun NH2-terminal kinase) proteins in the livers of experimental mice. The serum levels of insulin, IGF-1, IGF-2, free fatty acid, and TNF-α were all decreased by drinking EGCG, which also decreased the expression of TNF-α, interleukin (IL)-6, IL-1β, and IL-18 mRNAs in the livers. In addition, EGCG improved liver steatosis and activated the AMP-activated kinase protein in the liver. These findings suggest that EGCG prevents obesity-related liver tumorigenesis by inhibiting the IGF/IGF-1R axis, improving hyperinsulinemia, and attenuating chronic inflammation. EGCG, therefore, may be useful in the chemoprevention of liver tumorigenesis in obese individuals. Cancer Prev Res; 4(3); 396–403. ©2011 AACR. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|