The Expression Of PLKL And P21 WAF1/CIP1 In Hepatocellular Carcinoma

BackgroundHepatocellular carcinoma (HCC), one of common malignant tumor, is the most common histological types in primary liver cancer in China.The development of HCC is a multiple factors involved, more complicated process steps, including cumulative oncogene activation and tumor-suppressor gene inactivation, but its specific molecular mechanism is unclear. Therefore, to clarify the abnormal gene expression is of important significance for the mechanism of hepatocellular carcinoma.Plkl is one of the important kinase in mitosis to play many functions in the cell cycle. In recent years, the relationship between plk1 and tumor is got the attention of people, so far over-expression of plk1 protein has detected in patients with esophageal, stomach, liver, colorectal cancer and many other kinds of solid tumor tissues. Futhermore the over-expression of plk1 protein has significant correlation with the low survival rate of cancer patients, but the mechanism of over-expressed plk1 protein in tumor is unclear. Some research found that cell cycle inhibitor p21 c1P1 can directly act on p1k1 gene promoter area to restrain plk1 gene expression. suggesting that over-expression of plkl protein may be have some relationship with p21 protein in tumor tissue. In this study, expression of plk1 and p21WAP1/CIP1 protein was evaluated separately by Western-blot in 10 surgically resected hepatocellular carcinoma tissues. PFlex-p21 vector was transfected into liver cancer cell line HepG2, and the changes of plk1 mRNA expression and protein expression were detected using RT-PCR and western blot analysis respectively.The study of the correlation between p21 and plkl in hepatocellular carcinoma tissues could provide new experiment basis for the mechanisms of hepatocellular carcinoma.PurposeSome research suggest that the cell cycle inhibitory factor p21 WAF1/CIP1 (p21) can inhibit plkl gene expression in transcription level. In this paper we investigated the Expression and correlation between plk1 and p21WAF1/P1(p21) in Hepatocellular carcinoma.Material and method1. Tissue samples The subjects studied were 10 HCC cases who had undergone hepatectomy at the henan province tumor hospital. it is primary hepatocellular carcinoma from the pathological diagnosis. The corresponding non-tumorous liver tissue samples were taken from cancer tissue adjacent non-cancerous by outside 5cm. There liver tissue samples obtained from these 10HCC cases were freezed immediately in liquid nitrogen after surgical operation. Set aside. All liver cancer patients were men, with an average age of 51±11.53 years old. Informed consent was obtained from the patients for the use of their resected specimens for the investigation.2. Method Expression of plkl and p21WAF1/C1P1 protein was evaluated separately by Western-blot in 10 surgically resected HCCs tissue and the corresponding non-tumorous liver tissue samples. The changes of plk1 mRNA expression and protein expression were detected using RT-PCR and western blot analysis respectively after PFlex-p21 vector was transfected into liver cancer cell line HepG2.3. Statistical analysis Statistical analysis was carried out using the SPSS 11.5.the statistical method is t test. P＜0.05 is considered to be statistical significance.ResultsThe expression of plkl in the 10 cases HCC was higher than that in the adjacent liver cancer tissue. The expression of p21 in 7 cases liver cancer organizations was higher than that in the adjacent liver cancer tissue,but in other 3 cases the expression of p21 of HCC and the corresponding non-tumorous liver tissue was no obvious significant difference. The expression lever of Plkl protein and mRNA was not change significantly in Human liver cell lines HepG2 cells transfected pFlex - p21 plasmids and pFlex plasmids.Conclusions1. The expression of plkl and p21 in hepatocellular carcinom are higher than the corresponding non-tumorous liver tissue respectively.2. Plkl high expression has no definite relationship with p21 protein in hepatocellular carcinom.3. Over-expression of p21 proteins in liver cancer cell lines HepG2 can't restrain plkl gene transcription and plkl protein expression.