Studies On The Expression Of KAI1 Gene In Different Hepatic Tissues And Construction Of KAI1 Eukaryotic Expression Vector

Hepatocellular carcinoma(HCC) is a challenging disease because of limitations in surgical treatment and its unresponsiveness to adjuvant chemotherapy, radiotherapy and/or antihormonal treatment. The best therapeutic option to cure patients with HCC is surgical resection . However, despite successful resection , patients with HCC have a high rate of tumor recurrence and metastasis , resulting in short survival time . Although the high incidence of recurrence can partly be attributed to the often-associated cirrhosis in the remaining liver , certain characteristics of the cancer cells may be related to tumor recurrence . Primary HCC and tumor recurrences in the remnant liver are often associated with extrahepatic and intrahepatic metastases occurring via the portal and lymphatic systems . Thus, the presence of intrahepatic metastases and tumor thrombosis of the portal vein and its branches are considered to be the most important correlates of the metastatic potential of HCC . The metastatic potential of a malignant tumor is an important parameter that influences its prognosis . Metastasis formation is a complex process , involving local tumor growth , invasion of tumor cells and decreased host immunological responses . In this regard recent studies indicate that the invasiveness and dissemination of cancer cells are dependent on several genes.Recently, a new metastasis-related gene named KAI1 was discovered. Down-regulation of KAI1 mRNA expression in prostate, lung and pancreatic cancers has been associated with the presence of lymph node or distant metastases, indicating a major influence in metastasis formation. However, the role of KAI1 in HCC has not yet been defined. In this study we investigated the expression of KAI1 mRNA in the tissues of liver cirrhosis, hepatocellular carcinoma and normal liver by Northern blot and analyze the relationship between the expression of KAI1 mRNA and clinical parameters of patients with HCC. We found that the levels of KAI1 mRNA in the tissues of liver cirrhosis and HCC were significantly lower than those in the normal liver. There was no significant difference in the expression of KAI1 mRNA between the tissues of liver cirrhosis and HCC. There was no significant difference in the expression of KAI1 mRNA between the tissues of HCC with different differentiation , but the expression of KAI1 mRNA in the tissues of III stage HCC was obviously lower than those in II stage HCC.We concluded that the low expression of KAI1 mRNA in the tissues of HCC is correlated with invasive and metastatic potential. Then we constructed the eukaryotic expression vector of KAI1 by RT-PCR and molecular cloning technology; and the results of enzymatic digesting identification as well as genetic sequencing confirmed the successful plasmid construction, which make preparation for further study.