| Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in Asia and Africa, and with an annual mean incidence of 300,000. It has bacame the second leading reason among the malignant tumors that causes patients death in China. Recently the survival rate of HCC has been improved with better and better techniques of diagnosis and treatment. Exairesis of tumor is the most effective method by which patients may get long term survival, but even as radical excision, its racurrence rate of 5 years after operation can still reach up to 50%-60%. So it has became hot pot and nodus of improving curative effect on HCC to decrease the recurrence and metastasis rate of HCC after operation.Interferon (IFN) can inhibit evidently the growth of tumors through resisting hyperplasia to encourage apoptosis, inhibiting neovascularization, and immunological regulation. But its exact mechanism hasn't been known clearly. IFN has not manifest effects on solid tumors, although with successful experiences on treatment of some tumors origining specific hematopoietic cells in clinical. The proper administration time, dosage and methods need to investigate further.The tumorigenesis of human is caused by synergistic effect of multiple genes, multiple factors and multiple steps, involved in mutation of many oncogenes and anti-oncogenes, and many kinds of zymologic changes. Especially to genesis of HCC, many factors are involved in, for example gene mutation, amynologic changes, physiologic and biochemistric changes, hormonal regulation and so on. Among them, the expression of cyclooxygenase-2 (COX-2) and vascular endothelial growth factor (VEGF) in HCC has drawn more attention recently. The mechanism of HCC genesis and development may be revealed in some aspects through the deeper study on COX-2 and VEGF.To investigate the relationship between COX-2, VEGF and angiogenesis, clinical pathology in HCC, and between COX-2, VEGF and microvessel density (MVD), the expression of COX-2, VEGF in paraffin imbedding samples from 44 HCC patients was dectected by immunohistochemistry; MVD was measured through vascular endothelial cell count after marked by anti-CD34 monoclonal antibody. The pathologic characteristics of these samples were recorded at the same time, including pathology grades, tumor diameter, alpha fetoprotein, tumor number, amicula, metastasis and clinical stages. Then to identify the effect and clinical significance of COX-2, VEGF in HCC, the correlation between COX-2, VEGF, MVD and pathologic characteristics was analyzed.To explore the inhibition mechanism of interferon-α-2b(IFN-α-2b) to the growth of human HCC transplantation tumor, athymic mouse models of HCC was established. Then HepG2 cells were inoculated subcutaneouly into mice. After tumor formation, the groups were divided randomly basing on the different dosage of hypodermic injection of IFN-α-2b. Then the growth status of tumors was observed, the ratio of apoptosis in tumor samples of athymic mice was detected too. The mRNA and protein expression of COX-2 and VEGF in transplantation tumors was detected by semiquantitative RT-polymerase chain reaction (RT-PCR) and western blot. Basing on these results, it was performed to discuss the effect of IFN-α-2b on apoptosis and expression of COX-2 and VEGF in tumors; Meanwhile it was done to explore the different degree of inhibition of IFN-α-2b on the growth of tumors and different effect on apoptosis in tumors with different dosages.The results were attained as follows:1. The expression of COX-2 protein in well-differentiated HCC was higher significantly than it in moderately and poorly differentiated HCC (P<0.05); Meanwhile it in metastasis group was higher significantly than it in non-metastasis group (P<0.01). The expression of VEGF protein in metastasis group was higher significantly than it in non-metastasis group (P<0.01), and it had a same relationship between HCC with and without amicula (P<0.05). MVD in metastasis group was also higher significantly than it in non-metastasis group (P<0.01). There were manifest positive correlations between the expression level of COX-2 and VEGF, and between VEGF expression and MVD (r=0.6261, r=0.6097 respectively; P<0.001); but no one between COX-2 expression and MVD(r=1.304,P>0.05).2. The weight and volume of tumors in treatment group with IFN-α-2b were lower significantly than them in control group (P<0.01); the expression level of COX-2 and VEGF and MVD were also lower significantly in treatment group (P<0.01); meanwhile the ratio of apoptosis in tumors of treatment group increased manifestly compared with it in control group(P<0.01).3. In treatment group with IFN-α-2b, there were statistical differences in inhibition on tumor growth, the expression of COX-2 and VEGF and MVD of tumors among low dose group (10,000 IU/d), middle dose group (20,000 IU/d) and high dose group (40 000 IU/d) (P<0.05). IFN-α-2b had the most effective inhibition on tumors with middle dosage, meanwhile the expression level of COX-2, VEGF and MVD were lowest in middle dose group too. There was not significant difference between low and high dose groups in these aspects (P>0.05).the conclusions were drawn as follows:1. The over-expression of COX-2 was involved in well-differentiated HCC, and might play a role in early stage of HCC genesis. The expressiones of COX-2 and VEGF had relations with metastasis of HCC. They might improve angiogenesis of tumors with synergistic effect and then enhance the growth, invasion and metastasis of HCC.2. IFN-α-2b produced inhibition effect on the growth of HCC through two ways mainly. One, it could induce apoptosis of HCC by down-regulating the expression of COX-2; The other, it could down-regulate the expression of VEGF, inhibit angiogenesis of tumors and then refrain tumor growth. In addition, the expression of COX-2 might regulate or impact the expression of VEGF.3. IFN-α-2b had a dose-effect relationship in treatment of HCC, and had the most effective inhibition on the growth of tumors with middle dose (20,000 IU/d). it provided a new experimental foundation for chemical control of HCC.
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