出版年:

研究生:

王昱昇

研究生(英文姓名):

Wang, Yu-Sheng

論文名稱:

腦神經膠質瘤細胞FasL的調控

英文論文名稱:

Regulation of FasL expression in glioblastoma cells

指導教授:

楊倍昌

指導教授(英文姓名):

Yang, Bei-Chang

學位類別:

碩士

校院名稱:

國立成功大學　

系所名稱:

微生物暨免疫學研究所

學號:

S46861068

學年度:

87

語文別:

英文

論文頁數:

75

關鍵詞:

腦神經膠質瘤 ; 過度表現 ; 生長優勢

英文關鍵詞:

FasL ; Ras ; NF-kappa B ; Raf ; Glioblastoma ;
Jurkat ; overexpression ; growth advantage

被引用次數:

1

[ 摘要 ]

腦神經膠質瘤為人類常見的腦部惡性腫瘤，歷經數十年來的研究，發現一些致癌抑制基因和致癌基因的變化與腫瘤細胞惡化的程度息息相關，然而正常腦膠質細胞如何進行癌化並持續生長的原因仍尚待更多研究加以證實。目前所知，在大部分被研究的癌細胞株都發現FasL高度的表現，而且腫瘤細胞可能透過Fas/FasL結合所產生的死亡訊息造成前來抵禦的免疫細胞死亡，使腫瘤細胞得以生存。除此之外，在試圖發展對抗腫瘤的免疫力時，FasL的免疫抑制力亦必須設法加以克服。在本論文中，所研究的兩株腦神經膠質瘤細胞(U-118MG和U-373MG)表現的FasL量比正常glial來多。我們首要證實的是，促進這些癌化細胞大量表現FasL的刺激因子從何來，根據我們的假設，其可能與Ras的活性相關。在使用抑制Ras藥物、基因和NF-B 競爭胜 的實驗中，都可以造成FasL的表現下降。相反地，將活性Ha-ras基因送入正常glial後發現，FasL的量相對地昇高。因此，我們證實了腦神經膠質瘤細胞高度的FasL表現與 Ras活性間之關連性。其次，控制細胞FasL的表現是將針對FasL的mRNA 進行切除的ribozyme送入此兩株癌細胞內並篩選出穩定株。其中U-373MG細胞因胰島素所產生暫時性細胞死亡的現象不復見，與之共同培養的Jurkat細胞死亡的情形亦較緩和。這兩株所篩選出較低FasL表現的細胞在體外培養時都較具生長優勢。這一套人為控制FasL表現的研究系統，將利於有關腦瘤細胞生長之研究。

[ 英文摘要 ]

Glioma is reported frequently in human malignant brain tumors. The oncogenesis has been the subject of numerous studies through several decades. The alternation of tumor suppressor genes and oncogenes are investigated and verified the phenomena relevant to the progress of the tumor malignancy. How normal glial cells transform and grow requires further determination. Recently, FasL is believed gradually as an immune suppressor to facilitate tumor growth. Many cancer cells have been distinguished in high level of FasL expression. In some studies, Fas/FasL contact caused cell death to activated Fas-bearing lymphocytes infiltrating in cancer tissues. The escape from immune surveillance by FasL overexpression in tumors can be also the obstacle to the development of therapeutic anti-tumor immunity. We found FasL was overexpressed in two glioblastoma cell lines, U-118MG and U-373MG. Two issues were then studied. The first one is where the signal of FasL expression comes from. We hypothesize that it is transmitted from Ras activity. We blocked the Ras signaling pathway with lovastatin, NF-B competitive peptide, and dominant negative genes for Ras or Raf. FasL mRNA and protein decreased in the experiments. We also overexperssed active Ha-ras in glial cells and found an increase in FasL. In the second part of the study, we down-regulated FasL of glioblastoma cells by FasL specific ribozyme. The FasL interference in U-373MG reduced the insulin-associated apoptosis after serum starvation and delayed death in co-cultured Jurkat cells. The stable U-118MG and U-373MG cell lines receiving the ribozyme DNA had an advantage on cell growth in vitro. Taken together, we demonstrated the correlation of FasL overexpression with Ras activity and setup successfully an artificial modulation system of FasL expression.