- 學位論文
肝細胞癌之Caveolin-1與血管新生之探討
The Study of Caveolin-1 and Angiogenesis in Hepatocellular Carcinoma
摘要
目的： Caveolae為細胞膜上直徑大小約50-100 nm的凹陷結構，其參與許多細胞內訊號調節過程。Caveolin-1則是caveolae結構中主要的成分之一，先前研究指出某些癌症患者檢體內或癌症細胞株觀察到caveolin-1有表現量異常的情況。血管新生在癌症發展及轉移過程中扮演了正或負調控角色。本論文將藉由研究caveolin-1與血管新生因子eNOS、VEGF、 HIF-1α在肝細胞癌患者檢體內表現情形及其與患者臨床病理特徵相關性。進一步討論肝細胞癌患者檢體中，上述蛋白質於肝細胞癌發展過程中所扮演之角色。 材料與方法：本研究共收集75例由1995至2003年間接受肝細胞癌腫瘤切除手術所石蠟包埋之檢體進行caveolin-1、eNOS、VEGF及HIF-1α免疫組織化學染色，以半定量方式記錄其表現量及觀察這些分子染色的位置，並與患者的臨床病理特徵相互比對。且利用西方墨點法觀察caveolin-1在肝細胞癌患者檢體內的表現情況。 結果：Caveolin-1、eNOS、VEGF及HIF-1α在肝細胞癌患者體中表現各占 98.67%、82.67%、96%及52%，caveolin-1與其他eNOS、VEGF及HIF-1α這些血管新生相關因子彼此間不具統計上的相關性。分析臨床病理特徵與個蛋白質間相關性：caveolin-1及VEGF與患者的臨床病理分期分別具負相關性（P = 0.033）和正相關性（P = 0.050）、eNOS與患者的腫瘤分化分級呈正相關性（P = 0.003）。當caveolin-1的高度表現患者的存活率高於低表現患者（P = 0.0392），且caveolin-1低度表現與eNOS高度表現時患者預後較差（P = 0.0026），隨後以多變項變數分析，結果顯示Caveolin-1高度表現與eNOS低度表現與患者的復發相關（P = 0.020, P = 0.017）。此外，利用西方墨點法觀察患者檢體中的caveolin-1蛋白質表現則發現患者肝細胞癌腫瘤部分檢體caveolin-1 有異構物表現量降低的情況。 結論：由本論文實驗結果顯示，caveolin-1並非直接與eNOS、VEGF及HIF-1α相互作用調控血管新生的過程進而影響肝細胞癌發展。當caveolin-1表現量降低時患者存活率下降且容易復發。Caveolin-1低度表現與eNOS高度表現時患者存活率降低說明此兩蛋白質間可相互調控。因此caveolin-1 可做為肝細胞癌患者預後之預測因子。
並列摘要
Background：Caveolae are 50 to 100nm flask-shaped invaginations of the plasma membrane. The putative functions of caveolae include several intracellular physiological processes. Caveolin-1 is one of the major protein component of caveolae. It has been demonstrated that caveolin-1 is down- or up- regulated in several cancers. Angiogenesis is a crucial process for tumor growth and metastasis regulated by the balance of positive and negative factors. The aim of this study was to analyze the correlation among the expression of caveolin-1, eNOS, VEGF and HIF-1α with clinicopathologic features and outcome of hepatocellular carcinoma（HCC） patients. Materials and Methods：Based on immunohistochemical study, the expression levels of caveolin-1, eNOS, VEGF and HIF-1α in 75 HCC patients were investigated, and their correlations with clinicopathologic features were evaluated statistically. Furthermore, caveolin-1 protein expression was compared in cancerous and non-cancerous liver tissue using western blotting. Results：The positive rates of caveolin-1, eNOS, VEGF and HIF-1α staining were 98.67%、82.67%、96% and 52% in 75 HCC lesions, nespechively. There was no significant correlation among caveolin-1, eNOS, VEGF and HIF-1α. caveolin-1 and VEGF expression were correlated inversely with clinical stage（P = 0.033）. eNOS expression was correlated positively with histological grade （P = 0.003）. The patients with low caveolin-1 and high eNOS expression had a poor outcome（P = 0.0026）. Multivariate analyses indicated that vascular invasion, caveolin-1 and eNOS expression were identified as prognostic predictor. Conclusions：There was no correlation between caveolin-1 and angiogenic factors in this study. Our current results suggest that caveolin-1 may function as a tumor suppressor in HCC. Reduced expression of caveolin-1 and increased eNOS predict a poor outcome in a subset of patients.