2010-08-012024-05-13https://scholars.lib.ntu.edu.tw/handle/123456789/649113摘要：本計劃主要目的是要探討beta1,4-galactosyltransferase III (B4GALT3)對神經母細胞瘤(NB)的腫瘤生物特性、病理變化、病人預後的影響及其中的分子機制。NB源自於胚胎時期發育為人體交感神經系統的神經脊細胞（neural crest cells），也是幼兒期最常見的惡性腫瘤。大約60％的NB病患在診斷時已經是第四期，預後非常差，五年存活率大約只有40％。此腫瘤的特徵在於其多樣性，此特性亦表現於其病理組織檢查的型態學上。在NB中，往往可看到分化程度不同的腫瘤細胞組織同時存在。診斷時，組織病理上的分化程度和病人的預後也有相關，分化程度愈好者，預後愈好。雖然其病理成因仍然不明，但很可能是胚胎神經母細胞在發育過程中無法正常分化而造成。之前的研究顯示，癌細胞表面的醣類結構變化，包括醣蛋白及醣脂質，對癌細胞本身的生物特性和惡性程度有很大的影響。B4GALT3是一種glycosyltransferase，可改變細胞表面的醣類構造，但它對癌細胞生物特性的影響仍是未知。我們的前驅實驗發現B4GALT3的表現和NB病人腫瘤的分化程度有明顯的相關性：腫瘤的分化程度越好，B4GALT3表現越高。此外，在最近的文獻報告也發現在hepatoma HepG2及NIH 3T3細胞中，表現B4GALT3則可抑制colony的形成。這樣的結果表示B4GALT3在NB中可能和腫瘤的分化有關，並進一步影響NB細胞的惡性程度，並且也可能是病人重要的預後因子。所以我們提出一個假說，即在NB中，B4GALT3的表現會增進細胞分化、影響細胞的惡性程度並為病人重要的預後因子。本研究的目的就是想證實此一假說，同時探討其中牽涉的分子機轉。因此我們主要的目標為:1.確認B4GALT3的表現與NB分化程度及病人預後的相關性。我們會以免疫染色的方式在全部台大醫院的病人(約85位)腫瘤組織中，確認B4GALT3的表現與腫瘤組織分化程度的相關性，並以NB細胞株的實驗進一步確認這樣的關係。同時收集病人的臨床資料，和腫瘤組織B4GALT3的表現量比對後，探討B4GALT3的表現量與NB病人預後的相關性。2.確認B4GALT3的表現會影響NB細胞的惡性程度並探討其中牽涉的分子機轉。我們將會建立B4GALT3穩定表現的NB細胞株，在和B4GALT3不表現的細胞株比較後，觀察細胞生物特性及惡性程度的變化，並探討其中牽涉到的主要細胞訊息傳遞路徑。23.在活體實驗中確認B4GALT3的表現對 NB腫瘤生長、轉移及動物存活的影響。我們將以小鼠的動物實驗模式，將B4GALT3穩定表現及不表現的NB細胞株分別種在小鼠身上，來探討B4GALT3的表現在活體動物中，對NB腫瘤生長、轉移及動物存活的影響。本研究完成後，我們將確認B4GALT3的表現對NB病人預後的重要性，了解B4GALT3的表現在NB中如何影響腫瘤的分化和惡性程度，及其中牽涉的分子機制。藉由這樣的了解，希望未來可以進一步對這個腫瘤設計出新的治療藥物，增進治療的成績，改善病人的預後。<br> Abstract: The objective of this proposal is to investigate the biological and pathological role of beta1,4-galactosyltransferase III (B4GALT3) in neuroblastoma (NB). NB is one of the most common pediatric cancers and accounts for about 5% of malignancies in patients younger than 18 years old in Taiwan. It can develop anywhere in the sympathetic nervous system, but most commonly arises in the adrenal gland. Approximately 60% of NB patients are clinically diagnosed as the stage IV disease and have a very poor prognosis. NB is quite a heterogeneous tumor and presents a broad clinical and biologic spectrum ranging from highly undifferentiated tumors with very poor outcomes to the most differentiated benign ganglioneuroma or NB with high probability of spontaneous regression and hence favorable prognosis.Altered carbohydrate structures on cell surfaces are prominent features of cancer cells and play an important role in determining tumor malignant characteristics and metastatic potential. Changes in expression levels of glycosyltransferases lead to altered carbohydrate structures of N-linked and O-linked glycoproteins as well as glycolipids. B4GALT3 is a galactosyltransferase which contributes to the synthesis of polylactosamine. Although the in vitro enzymatic activity of B4GALT3 has been studied, its expression in tumors and its role in regulating tumor properties are still unknown.Our preliminary data showed that B4GALT3 expression was higher in NB tumors with more mature differentiation histology. In addition, overexpression of B4GALT3 has been reported to suppress the colony formation of hepatoma HepG2 and NIH 3T3 cells. We therefore hypothesize that B4GALT3 expression is a prognostic factor of NB and its expression can affect NB cell behaviors. In this proposal, we will study the role of B4GALT3 in human NB and the molecular mechanisms by which B4GALT3 affects the cellular properties of NB cells.Our specific aims are to: 1. Verify the association of B4GALT3 expression and NB tumor differentiation and the prognostic roles of B4GALT3 expression in NB patients. We will exam the association of B4GALT3 expression and NB tumor differentiation by immunohistochemistry of all NB patients at present in National Taiwan University Hospital (about 85 cases) and by in vitro NB cell studies. The clinical data of these NB patients will be collected and prognostic role of B4GALT3 expression in these patients will be verified. 2. Determine the effect of B4GALT3 expression on NB cell behaviors and the underlying mechanisms by which B4GALT3 affects the NB cell behaviors. B4GALT3 stable transfectants of NB cells will be established. The malignant behaviors of B4GALT3 stable transfectants will be compared with mock transfectants. We will further determine the major signaling pathways by which B4GALT3 affects the NB cell behaviors.3. Determine the effect of B4GALT3 expression on NB tumor growth, survival, and metastasis in vivo. To investigate whether B4GALT3 overexpression will alter NB tumor growth, survival, and metastasis in vivo, we will compare the NB tumor growth, survival, and tumor metastasis in SCID mice bearing B4GALT3 stable transfectants and mock transfectants.Altogether, our study will not only define the prognostic role of B4GALT3 expression in NB patients, but also depict the molecular mechanism by which B4GALT3 regulates differentiation and tumor behaviors of NB. The results may further provide us the information to develop therapeutic drugs for the treatment of NB in the future.