| Tumorigenesis is a multi-step process that requires activation of oncogenes and inactivation of tumour suppressor genes. Tumor growth depends on 2 distinctive pathways: cell proliferation and apoptosis. The p53 gene is a tumor suppressor gene, its activity stops the formation of tumors. The p53 pathway is an important regulator of the cell cycle as it triggers growth arrest or leads to apoptosis in response to cellular stress and therefore is commonly targeted during tumorigenesis. Mutations in p53 are found in most tumor types, and so contribute to the complex network of molecular events leading to tumor formation.Rho GTPases belong to the Ras superfamily of small GTPases and control a wide variety of cellular processes such as actin cytoskeleton rearrangement, microtubule dynamics, cell adhesion and polarity. Like all members of the Ras superfamily, Rho GTPases function as conformational switches by cycling active GTP and inactive GDP-bound forms. The cycle is regulated by two classes of protein, guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins. RhoA is a small GTPase involved in morphogenesis, cell adhesion, and cell cycle control. RhoA is a potential oncogene, causing cell malignant transformation.Recently studied showed that GEF-H1, a guanine exchange factor-H1 for RhoA, is transcriptionally activated by the induction of mutant p53 proteins, thereby accelerating tumor cell proliferation. Furthermore, growth of mutant p53 cells was dependent on GEF-H1 expression, whereas that of WT p53 cells was not. These results suggest that increased RhoA expression contributes to the tumor progression phenotype associated with the p53 mutation.Objective: To investigaste the expression of RhoA and mutant p53 gene in the HCC tissue, latero-HCC tissue and the normal liver tissue from the level of molecular biology. Analyze the expression of RhoA and mutant p53 gene in pathology's feature of HCC, the correlation between the RhoA and mutant p53 expression in HCC tissue. To explore the effects of RhoA in the birth and growth process of HCC.Methods: Thirty one samples which excisional specimen by operation which is confirmed HCC through pathological section in our hospital from May, 2006 to February, 2007 were selected to study. With the method of immunohistochemistry and RT-PCR (Reverse transcription polymerase chain reaction) determine respectively the level expression of mutant p53, RhoA, mutant p53 mRNA, RhoA mRNA in the 31 specimen of HCC, homologous latero-HCC tissue and 6 normal liver tissue. Analyze the feature of expression on p53, RhoA, mutant p53 mRNA, RhoA in the sample of HCC and the tissue of latero-HCC tissue, with the combination the information of differentiation's degree of the liver cancer, the level of AFP, HbsAg, whether hepatic cirrhosis complication and the tumormetastasis.Results: (1) Immunohistochemistry shows:①the rate of the RhoA's positive expression in the tissue of HCC(61.3%, 19/31) is obviously higher than that in latero-HCC tissue(14.8%, 4/31), the comparision between them (P<0.01).②p53's positive expression in the tissue of HCC(45.2%, 14/31) is obviously higher than that in latero-HCC tissue(16.1%, 5/31), the comparision between them(P < 0.01).③the rate of RhoA's positive expression in the tissue of HCC with the in poor differentiation degree(78.3%, 18/23) higher than that in well differentiation HCC tissue(12.5%, 1/8), the comparision between them (P<0.05). And the rate of RhoA's positive expression in the tumor metastasis(92.3%, 12/13) is obviously higher than the normal tissue of HCC(38.9%,7/18), the comparision between them (P<0.01), Otherwise, the rate of RhoA's positive expression in the tissue of HCC with hepatic cirrhosis complication significantly(72.0%, 18/25) higher than without hepatic cirrhosis complication(16.7%, 1/6), the comparision between them (P<0.05). Comparision the rate of HbsAg, the level of AFP and the tumor's size, is no significantly distinction.(2) RT-PCR semiquantitative analysis confirmed:①the level of RhoA mRNA expression in HCC tissue higher than that of latero-HCC tissue(0.628±0.012vs0.350±0.012), the comparision between them (P<0.01).②the level of mutant p53 mRNA expression in HCC tissue higher than that of latero-HCC tissue(0.395±0.017vs0.310±0.013), the comparision between them (P<0.01).③the rate of RhoA's expression in the tissue of HCC with the in poor differentiation degree higher than that in well differentiation HCC tissue(0.666±0.012vs0.520±0.037), the comparision between them (P<0.01). And the rate of RhoA's expression in the tumor metastasis is obviously higher than the normal tissue of HCC (0.701±0.010vs0.576±0.011), the comparision between them (P<0.01), Otherwise, the rate of RhoA's expression in the tissue of HCC with hepatic cirrhosis complication significantly higher than without hepatic cirrhosis complication(0.656±0.012vs0.512±0.040), the comparision between them (P<0.01). Comparision the rate of HbsAg, the level of AFP and the tumor's size, is no significantly distinction.(3) Correlation Analysis shows:①Immunohistochemistry shows: The rate the positive expression of RhoA in the p53 positive samples is 85.7%(12/14). And 41.2%(7/17) of RhoA was no expression in p53 negative expression group. Fisher's exact probabilities in 2X2 table shows significantly correlation with p53 and RhoA, the comparision between them(P < 0.05).②RT-PCR shows: Pearson correlation shows significantly correlation with mutant p53 and RhoA, r = 0.754, (P<0.01). Conclusions: (1) RhoA overexpression takes part in the process of the birth, growth of hepatic cancer. The level of RhoA's expression is related with the degree of the HCC, whether metastasis and hepatic cirrhosis complication. The level of RhoA's expression isn't obviously related with the combining the hepatitis of type B, the level of AFP, the size of tumor.(2) RhoA and mutant p53 are tightly related in the expression of HCC. Mutant p53 intervenes the expression of RhoA. We suppose it's one pathways that mutant p53 gene active RhoA gene and accelerate the tumor's growth.
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