骨橋素調控人類惡性神經膠質瘤細胞的侵襲與增生能力

Osteopontin regulates human glioma cell invasiveness and tumor growth

詹勳錦(Hsun-Jin Jan)

指導教授 ： 李宏謨

臺北醫學大學/醫學院/醫學科學研究所/博士(2009年)

摘要

人類惡性神經膠質瘤細胞具有快速增生和強烈侵襲能力的特性。本研究証實在不同人類惡性膠質瘤細胞株中，骨橋素Osteopontin (OPN)的表現量與人類神經膠質瘤細胞株的增生速率及侵襲能力呈正相關性。為了探究骨橋素與腦瘤之間的關係與骨橋素是否可作為腦瘤的標靶治療分子，本研究利用核?˙臚p髮夾RNA(Small hairpin RNA，shRNA)減幅人類惡性膠質瘤骨橋素的表現，並表現減少骨橋素的表現能有效的降低膠質水解??(Matrix Metalloproteinases, MMP-2)活性和減弱細胞的侵襲能力，減緩在鼠腦內腫瘤的增生速率與侵襲面積。這些結果顯示骨橋素在人類惡性膠質瘤細胞增生和侵襲扮演重要角色。反之，於低度表現骨橋素的腦瘤細胞當增加骨橋素的表現於時，可提高細胞的膠質水解?′〝囥M侵襲能力，顯示骨橋素可能會調控細胞的基質金屬水解?′〝囥M侵襲能力。除此之外，骨橋素的表現還會影響膠質纖維酸性蛋白(Glial Fibrillary Acidic Protein；GFAP)
與中間波形蛋白纖維(Vimentin)的表現情形，顯示骨橋素可以影響人類惡性膠質瘤細胞的分化(Differentiation)。此外，本實驗也發現骨橋素可以調控低氧誘導因子-1α（Hypoxia inducible factor-1α、HIF-1α）的表現。實驗中證實低氧誘導因子-1α在非缺氧狀態下，可影響腦瘤細胞的侵襲與代謝及粒線體的膜電位。先前的實驗已證實血癌治療用藥5-AzadC (5-Aza-2'-deoxycytidine)可以活化絲裂原活化蛋白激?‘h磷酸??-1(Mitogrn activated protein kinase phosphatase-1 MKP-1)，且證實絲裂原活化蛋白激?‘h磷酸??-1 可以有效抑制低氧誘導因子-1α。在本實驗中証實5-AzadC 可減低骨橋素的產生與有效抑制鼠腦中腫瘤的增生與侵襲。綜合以上結果可以得知，骨橋素在人類惡性神經膠質瘤細胞進程中扮演非常重要角色，在未來5-AzadC 可當做重要治療標靶藥物可以有效控制經由骨橋素所誘發的人類惡性膠質瘤的腫瘤特性。

關鍵字

骨橋素 ； 人類惡性神經膠質瘤細胞

並列摘要

Human malignant glioma cells are characterized by invaded-growth of adjacent
tissues. In this study, we demonstrated that different human glioma cells exhibit
distinct capacity of invasiveness and proliferation in vitro and in vivo. Osteopontin
(OPN) protein and mRNA levels correlate well with their capacity of proliferation and
invasiveness. In order to understand whether OPN plays a therapeutic target to
strategy of glioma treatment, glioma cells were stable expressed with specific shRNA
to knockdown OPN expression, subsequently MMP-2 activity and expression were
dramatically reduced. OPN-knockdown also reduced cell invasiveness and
proliferation in glioma cells. In animal model, knockdown of OPN expression
resulted in decreasing of tumor growth in vivo. In contrast, forced OPN expression
in glioma cell with lower OPN level, we found OPN promoted cell invasiveness and
proliferation in vitro and in vivo. These results suggest that OPN may serve a role in
glioma cell invasiveness and proliferation. The ratio of Glial fibrillary acidic protein
(GFAP) and Vimentin have been demonstrated that strong correlated with glioma
malignancy. We found that OPN alters GFAP/Vimentin ratio in glioma cell lines,
suggesting that OPN might regulated the differentiation state in glioma cells. We
investigated that OPN regulated hypoxia inducible factor-1α(HIF-1α) expression in
glioma cell lines. We have demonstrated that HIF-1α plays the pivotal role in cell
invasiveness, metabolism and mitochondria membrane potential in glioma cells. In
our previously studies, we demonstrated that 5-AzadC (5-Aza-2'-deoxycytidine)
induced MKP-1 (Mitogrn activated protein kinase phosphatase-1) expressionin
glioma cell lines. We also found that MKP-1 supressed HIF-1αexpression in human glioma cell lines. Finally, we explore that 5-AzadC reduced OPN expression, led todecrease cell invasiveness and proliferation in vitro and in vivo. Taken together, OPN signaling pathway may play an important role in glioma progression involved in cell invasiveness and tumor growth. Given 5-AzadC can regulated OPN expression in glioma cells. Furthermore, 5-AzadC may serve as a pivotal therapeutic drug in OPN-induced malignant glioma.

並列關鍵字

Osteopontin ； human glioma cell

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