- 學位論文
Centrosomal proteins和Aurora family 在人類腦瘤中的差異性表現
Differential expression of centrosomal proteins and Aurora family in human brain tumors
摘要
中文摘要 腦腫瘤常見有星狀細胞瘤、腦膜瘤及腦轉移瘤，其成因與年齡及其位置有關。在細胞分裂中，染色體及中心體複製和分離皆需精確的執行，假如發生錯誤，皆可能導致細胞分裂的不正常。早在1914年，Boveri推測中心體能引起染色體錯誤分離及異倍體，進而造成癌症的形成。在2001年，Doxsey利用轉殖中心體蛋白pericentrin進入正常攝護腺細胞中可誘導出tumor-like的細胞株，也有報告指出在乳癌形成時，中心粒放大會驅使染色體的不穩定等。除此之外，研究報告指出Aurora A在許多腫瘤組織及細胞株中被過度表現，例如：乳癌､結腸癌､膀胱癌､胰臟癌､神經膠質瘤等，也指出Aurora A參與了中心體的成熟､染色體分離及維持基因穩定且Aurora A過度表現會誘導中心體異倍體(centrosome aneuploidy)及中心體放大(centrosome amplification)。然而，常見的中心體蛋白包括hNinein isoforms､centrin､γ-tubulin，它們雖然在microtubulin nucleation扮演重要角色，但是在腦腫瘤細胞中異常表現的功能仍然不清楚。本篇研究，我們將分析中心體蛋白的表現與腦腫瘤生成關係。我們首先使用Reverse Transcription–PCR數據分析，發現中心體蛋白及Aurora family被過度表現， 並且它們在不同腦腫瘤有不同差異性表現，此外，令人感興趣地，hNinein isoform 6僅表現於正常大腦､星狀細胞瘤(17/34)，但並不表現於腦膜瘤(0/29)､腦轉移瘤(0/6)及星狀細胞瘤細胞株，但存在於IMR-32神經細胞瘤細胞株；且在星狀細胞瘤中，γ-tubulin､ hNinein isoform 6表現與否似乎與星狀細胞瘤惡性程度有關係，其中hNinein isoform 6功能的失去，可能扮演抗腫瘤基因(tumor suppressor genes)的功能；更進一步地，我們使用免疫組織染色(IHC)､免疫螢光染色(IIF)以及共軛交顯微鏡方法證實星狀細胞瘤中，Aurora A､hNinein､γ-tubulin有過度表現現象並且觀察到中心體異倍體及中心體放大。綜合上述研究，顯示在腦腫瘤形成中，中心體蛋白和Aurora family的過度表現會誘導中心體不正常行為進而造成癌症形成。
並列摘要
Abstract The brain tumor development is different in age and tissue location, such as the meningioma, astrocytoma and metastasis tumor. The faithful distribution of the genetic material between daughter cells during cell division requires the precise segregation of duplicated chromosome and centrosome. Boveri (1914) speculated that centrosomes could contribute to chromosome missegregation and aneuploidy and this phenomenon may contribute to tumorgenesis. At 2001, Doxsey transected centrosomal protein (pericentrin) into normal prostate cell line and contribute to development of tumor-like cell line. Besides, Centrosome amplification drives chromosomal instability in breast tumor development. Furthermore, Aurora A is member of the mitotic kinase, has been shown to be localized at mitotic spindle poles and is involved in regulating centrosome maturation, chromosome segregation and maintaining genomic stability. In addition, Aurora A were found to be overexpressed in several human cancer type, such as breast cancer, colorectal cancer, blander cancer and gliomas.To gain insights into the molecular basis of the brain tumor formation, we therefore examine the differential expression of Aurora family kinase and various centrosomal proteins (including centrin, ??-tubulin and hNinein isoforms) in human brain tumor samples from KMUH medical center using reverse transcription polymerase chain reaction. Our data show that centrosomal proteins of brain tumors and cell lines display a differential expression. Interestingly, hNinein isoform 6 was only expressed in the cases of normal brain, and astrocytoma tumors (17/34), whereas it was not expressed in meningioma (0/29), metastastic tumors (0/6) and examined cell lines (1/6) except one neuroblastoma cell line. Differential expression of ??-tubulin and hNinein isoform 6 in astrocytoma is correlated to tumor grade. The data also indicate that loss of function of hNinein isoform 6 may function as a tumor-suppressor gene in astrocytomas. Further more, we use Immunofluorence staining and confocal microscopy to find that Aurora A, hNinein and ??-tubulin are shown overexpressed together with centrosome aneuploidy in glioblastoma multiform.These data suggest that centrosomal proteins, including centrin, ?n??-tubulin, hNinein isoforms and Aurora family kinase may be attributed to inappropriate centrosome behavior during various brain tumors progress.