The Expression And Potential Role Of Metastasis Associated Protein-1 In Chemical Carcinogen Induced Carcinogenesis Of Mouse Liver

IntroductionLiver cancer is one of the most important diseases which are serious threats to people's health and lives. Liver cancer has badly affected Chinese. According to the statistics, each year about 11 million people died of liver cancer in China, which accounts for about 45% of the world's total. It often happens in middle-aged above, men much more than women. For the lack of clinic features, liver cancer often were found already bound into the more advanced. Therefore, the right animal models have a great help for the research of the development of the liver cancer. Metastasis-associated proteins are parts of NuRD (nucleosome remodeling histone deacetylase) complex which possesses both ATP-dependent nucleosome remodeling and histone deacetylase activities. They were also closely related to the process of invasion and metastasis of liver cancer. MTA1 is the founder of MTA family, which has multiple phosphorylation sites of tyrosine kinase, protein kinase C and casein kinase. This indicates MTA1 may perform its functions by affecting the signal transduction pathways. Although researchers believed MTA1 was associated with liver cancer metastasis, the specific mechanism and the lesions'correlation of MTA1 in liver cancer developing stages has not been clearly elucidated.In previous studies, it was founded that MTA1 might play a role in the process of invasion and metastasis of primary liver cancer. The prognosis of the liver cancer with high level of MTA1 expression were significantly poorer than those with low expression. But the mechanisms underlining this biological phenomenon have remained unclear. In order to shed more light on the relationship between MTA1 and liver carcinogenesis, we used the DEN induced heptocarcinoma model and examined MTA1 expression in the process of the heptocarcinoma development at the level of mRNA by RT-PCR, and protein level by both immunohistochemistry.ObjectiveTo establish a liver injury model of BALB/c mouse induced by DEN/CCl4/alcohol, and explore whether this animal model meets the liver cancer's characteristics and how the changes of MTA1 in the modeling process influence the pathological changes by HE staining, transmission electron microscope, IHC and RT-PCR.Methods1.The combination of DEN /CCl4/ alcohol was used to induce normal BALB/c adult male mice to generate liver tumor. Different period samples of experimental animals were drawn, liver lesions was observed by HE, and changes of other organs in mice were observed and recorded in the process.2.Total RNA of liver lesions samples in different periods were extracted, and RT- PCR was used to detect mAFP and MTA1 changes in different periods of mouse liver tissue lesions.3.On the 150th day, appropriate lesion site was selected to detect by electron microscopy examination, for observing liver cell ultrastructural changes.4. The expression of MTA1 in liver lesions site was observed by using specific MTA1 antibodies to liver lesions in the different time in immunohistochemical detection.Results1.At different stages, samples in mice appeared with varying degrees of hepatitis, liver fibrosis and cirrhosis and liver cancer performance in sequence.We also found that there were lesions in mice'eyes and pancreas.2.With the development of mice's lesions, the level of mAFP has increased .This indicates this mouse model is the type which secretes AFP, just like human primary liver carcinoma. The level of MTA1 has increased, too.3.In the first 150 days, the ultrastructure of mice'liver lesions were accord with the ultrastructural changes of hepatocellular carcinoma, by transmission electron microscope.4. The results of MTA1 immunohistochemical stains indicated that the level of MTA1 has increased in the process of liver lesions aggravating in mice immunohistochemical staining. And we found two very interesting phenomena: firstly, the level of MTA1 in the serious inflammation cells increased much more, which indicates MTA1 may has a relationship with inflammation level; secondly, MTA1 mainly expressed in the cytoplasm in the diseased cells'cirrhosis, which was very different from the early research results. Conclusions1.The model of hepatocarcinoma in BALB/c mouse induced by the combination of DEN/CCl4/alcohol was successfully built. This model's physiological characteristics were like human hepatocarcinoma's.2.The expression of MTA1 has increased in the process of liver lesions, and MTA1 mainly expressed in the cytoplasm in the diseased cells'cirrhosis. The changes of MTA1's expression sites and quantity in liver lesions indicated that MTA1 may play a role in the whole process of liver cancerization.