Cortactin Overexpression Contribute To Invasion And Metastasis In Hepatocellular Carcinoma

Evidence show that invasion is the most important factor which can raise recurrence rate of HCC(hepatocellular carcinoma). High invasiveness leading up to tumor spread within liver, portal vein invasion by malignant cell and tumor extension outside liver indicate poor prognosis of HCC. Cortactin is implicated in various aspects of cell function through phosphorylation including cell movement and migration. It has been found that much of its function is related to regulation of the formation of podosomes, tumor invasion and metastasis. Moreover, the invasion and metastasis of HCC have been observed inhibited by antisense CTTN(cortactin gene) expression vector. But there is lack of clinical research concerning the relation between CTTN expression and HCC invasion at the present time. For this reason, the author in this study applied IHC(immunohistochemistry) and RT-FQ-PCR(real-time fluoresence quantitative polymerase chain reaction) to detect CTTN expression level with the intention of demonstrating that overexpression of CTTN enhance HCC invasiveness.To investigate the expression and clinical significance of cortactin in HCC and to develop a method by which the invasion and metastatic potential could be graded, the expression of cortactin was detected by IHC in human HCC specimens. The level of cortactin expression and its relationship with clinicopathologic parameters was analyzed. To develop a method for detection of CTTN expression in HCC, total RNA(ribonucleic acid) was extracted from human HCC samples. CTTN and GAPDH(glyceraldehyde phosphate dehydrogenase) gene were amplified by RT-PCR(reverse transcription-polymerase chain reaction). The products of each gene were inserted in pMD18-T vector to build standard curves by RT-FQ-PCR with SYBR Green I. Human HCC tissue samples were detected based on the standard curves and the Ct(threshold cycle) value were analyzed to evaluate the precision, linearity and reproducibility. To investigate the relationship of CTTN expression with invasion and metastasis, total RNA was extracted from human HCC tissues and normal hepatic tissues adjacent to cavernous hemangiomas of liver. By using the standard curves aforementioned, the expression of CTTN and GAPDH were detected and the relative values were analyzed with specimens grouped according to their invasive power.IHC results showed that the level of cortactin expression was significantly correlated with integrity of tumor capsule, clinical stage, portal vein tumor thrombus and presence of extrahepatic metastatic. The tumor invasiveness was direct correlated with the level of cortactin expression. pMD18-T(+)/CTTN and pMD18-T(+)/GAPDH recombinant plasmid were established and confirmed as expected. When the concentration of temples were 1.6×10(?)-1.6x10(?)and 1.6×104-1.6x107 copies/μl, CTTN and GAPDH standard curve had good linearity respectively. The repeatability of two genes had no significant difference within run and between days. The level of CTTN mRNA(messenger ribonucleic acid) was significantly higher in high invasive HCC tissues than that in low invasive tissues and noncancerous tissues. There was no statistical significance between low invasive HCC tissues and noncancerous tissues.These findings support a correlation of cortactin with the invasiveness in HCC, suggesting a prognostic implication of cortactin. The method developed in this study show its value in the detection of CTTN expression in a wide range with advantage of sensitivity, specificity and repeatability. The results give evidence that overexpression of CTTN contribute to tumor invasive and metastasis in HCC, and the level of CTTN expression should be a helpful marker to judge the invasive and metastatic potential of liver cancer.