2018-08-012024-05-15https://scholars.lib.ntu.edu.tw/handle/123456789/662648摘要：(A) 背景及重要性： 細胞醣基化(glycosylation)異常是癌症的一項重要特徵。包括黏液蛋白(mucin)在內的許多不同種類蛋白進行O-醣基化的起始步驟皆為藉由N-乙醯半乳糖氨基轉移酶(GALNTs)家族的作用來將乙醯半乳糖胺連接到serine或threonine殘基的羥基上。目前已經發現GALNTs與許多癌症發展相關，有些為致癌、有些則為保護功能。我們發表在2017年Oncotarget期刊的研究已經顯示GALNT6與卵巢癌病人「較差」的預後明顯相關，而其作用主要因為GALNT6造成EGFR異常O-醣基化。 在過去幾年中，我的主要研究興趣是“癌症中的O-醣基化改變”。我們實驗室已經發表了一系列論文，內容包括討論在癌細胞中頻繁改變的轉移酶傳導路徑、醣基化改變和臨床預後的相關性、醣基化改變的基因基礎，以及利用體外細胞和動物實驗研究這些路徑在惡性腫瘤中的重要性。 近日我們進行了文獻搜尋以及卵巢癌組織檢體的初步研究發現，GALNT2的表現量增加與病人「較好」的預後顯著相關。再者，利用CRISPR/Cas系統來降低卵巢癌細胞內GALNT2的表現反會增加細胞的惡性表徵。這些結果強烈反映出GALNT2在卵巢癌癌化過程中與GALNT6同樣佔有重要角色。綜合而言，GALNT2在卵巢癌中的「保護作用」以及與其他GALNTs作用(例如GALNT3與GALNT6)的關聯性都相當值得深入探討。(B) 我們的假設： 異常表現的GALNT2改變了卵巢癌細胞的惡性及侵襲能力。抑制GALNT2會增加腫瘤惡性程度，並抑制卵巢癌細胞對癌症化療藥物的敏感性。(C) 研究目的與方法：1. 為了確定GALNT2在卵巢癌中的保護角色，本實驗將利用癌細胞株及動物模型來過量或減少GALNT2表現，進而研究GALNT2所媒介之細胞的生長、活動和侵襲能力的變化；並釐清GALNT2抑制卵巢癌癌化主要相關的分子機轉；並研究增加GALNT2是否可以提高卵巢癌細胞對化療的靈敏性。2. 為了分析GALNT2與其他GALNTs在卵巢癌細胞中相互作用的影響，研究將使用卵巢癌組織微陣列來研究GALNT2與不同GALNTs表現之間的關聯性; 並研究不同GALNTs所修飾的細胞表面和細胞中的O-聚醣表現變化; 並研究在穩定降低GALNT2表現的癌細胞中同時過量表現其他GALNTs對於細胞惡性行為的變化。<br> Abstract: (A) Background and significance: Altered glycosylation is a hallmark of cancer. The N-acetylgalactosaminyltransferases (GALNTs) family conducts the transfer of N-acetyl galactosamine (GalNAc) to the hydroxyl group of a serine or threonine residue in the first step of O-glycosylation of different proteins, including mucins. GALNTs are involved in multiple cancer developments, including oncogenic and protective functions. Our published paper in Oncotarget 2017 has shown that GALNT6 overexpression predicts poor prognosis and enhances malignant phenotypes via altering O-glycosylation on EGFR in ovarian cancer (OVCA). During the past years, my main research interest is “O-glycosylation changes in cancer”. Our lab have published a series of paper discussing some specific enzymatic pathways that are frequently altered in cancer cells, the correlational patterns between altered glycosylation and clinical prognosis, the genetic basis of some of these changes, and the in vitro assays and in vivo studies that indicate the importance of these pathways in malignancy. Recently, we conducted a literature search and preliminary examination of OVCA tissue specimens. We found that the increased expression of GALNT2 correlates with a better prognosis in OVCA patients. Furthermore, knockdown of GALNT2 in OVCA cell lines increased the malignant phenotypes of cells. These results strongly suggest that GALNT2 also plays a critical role in the carcinogenesis of OVCA as GALNT6. Taken together, the protective role of GALNT2 in OVCA and its interaction with other GALNTs (ex. GALNT3 or GALNT6) are worthy of further discussion.(B) Our hypotheses Aberrant expression of GALNT2 alters the malignant behaviors of OVCA cells. Knockdown of GALNT2 can increase tumor malignancy and decrease cell chemosensitivity.(C) Our specific aims:1. To study the protective roles of GALNT2 in OVCA cells, the study will investigate the overexpressed or knockdowned GALNT2-mediated growth, motility and invasive changes of OVCA cells in vitro and in vivo; identify the target of GALNT2 and the underlying mechanisms affecting OVCA malignant behaviors; and study whether knockdown of GALNT2 can decrease OVCA cells to chemotherapy- induced apoptosis.2. To analyze the effects of interaction between GALNT2 and other GALNTs in OVCA cells, the study will investigate the association of GALNTs expression using tissue microarrays; evaluate the O-glycan expression on cell surfaces and in cells modified by different GALNTs; and study overexpressed GALNTs in stable GALNT2 knockdown OVCA cells to investigate the changes of malignant behaviors.N-乙醯半乳糖氨基轉移酶第2型卵巢癌醣基化化療抗性GANLT2Ovarian cancerGlycosylationChemoresistance