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標題: | MBNL2及其造成的mRNA的剪接在肝細胞癌發生的角色 The role of MBNL2 and its regulated mRNA splicing in liver carcinogenesis |
作者: | Yu-Hsin Lee 李宇心 |
指導教授: | 鄭永銘(Yung-Ming Jeng) |
關鍵字: | 肝癌,muscleblind-like蛋白質,選擇性剪接,肝臟幹細胞,增殖, hepatocellular carcinoma,alternative splicing,muscleblind protein,hepatic progenitor cell,proliferation, |
出版年 : | 2014 |
學位: | 碩士 |
摘要: | 真核細胞mRNA前驅分子經過剪接的過程成為成熟的mRNA,而mRNA前驅分子的選擇性剪接可增加蛋白質的多樣性和基因表達的複雜程度。選擇性剪接不僅影響細胞的分化及個體的發育,目前已知許多遺傳疾病以及癌細胞的產生與轉移都與mRNA的剪接有密切的關係。人類muscleblind-like蛋白質(muscleblind-like protein, MBNL protein)是RNA結合蛋白,可調節RNA的選擇性剪接。近期的研究發現,在胚胎幹细胞中提高muscleblind-like蛋白質的表現量,可誘導分化特性的選擇性剪接事件產生。在我們的實驗中發現,經由免疫組織化學染色法可看到MBNL2會染在肝臟幹細胞所在的區域 (Canal of Herring)以及由肝臟幹細胞所新生成的肝細胞內,MBNL2也會染在具癌前病變特徵的異生性肝臟結節(75%)和肝細胞癌(59.8%)的區域。在統計分析中發現,當腫瘤大小大於5公分時,MBNL2表現量高的比例(25.7%)比小於5公分的比例(49.3%)要少(p=0.004),因此我們認為在肝癌發生的過程中MBNL2的減少會使腫瘤生長的更大。在體外培養實驗中,提高HepJ5肝癌細胞的MBNL2表現量,會減少細胞增殖的速度、聚球(sphere formation)能力、爬行和侵犯的能力,並在小鼠異種移植的試驗中減少腫瘤生長的大小。反之,經由核糖核酸干擾(RNA interference)的方式,剃除HA22T和Huh7肝癌細胞中的MBNL2表現量,在體外培養實驗中會增加細胞爬行和侵犯的能力,但並不足以促進腫瘤的生長。綜合上述的實驗結果,我們證明了MBNL2在肝癌發生的過程中扮演了一個腫瘤抑制蛋白的角色。 Pre-mRNA alternative splicing is an essential step in the process of gene expression. It provides cells with the opportunity to create different protein isoforms. Most human genes undergo alternative splicing events, and disruptions of this process have been associated with a variety of diseases, including cancer. The muscleblind protein (MBNL), an RNA binding protein, is a splicing-regulating factor. Recently, it was found that overexpression of MBNL proteins in embryonic stem cells promotes differentiated cell-like alternative splicing patterns. In our study, we performed immunohistochemical staining in liver tissue and hepatocellular carcinoma (HCC), and we found MBNL2 was stained on canal of Herring and hepatocytes newly derived from hepatic progenitor cells. MBNL2 was overexpressed in premalignant dysplastic nodule (75%) and HCC (59.8%). Further statistical analysis showed the percentage of MBNL2-high group in tumor size > 5cm group (25.7%) is less than in tumor size ≦5cm group (49.3%) (p=0.004) , indicating MBNL2 loss might enhance tumor growth in late HCC development stage. Overexpression of MBNL2 in Hep-J5 suppressed proliferation, sphere formation, migration, and invasion in vitro and reduced in vivo tumour growth in NOD/SCID mice. In contrast, depletion of MBNL2 with RNA interference in HCC cell line HA22T and Huh7 caused an increase in migration and invasion in vitro but did not enhance tumor growth. Our results indicate that MBNL2 is a tumor suppressor protein in liver carcinogenesis. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/18840 |
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顯示於系所單位: | 病理學科所 |
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