PTEN gene transfer suppresses the invasive potential of human malignant gliomas by regulating cell invasion-related molecules.
PTEN gene transfer suppresses the invasive potential of human malignant gliomas by regulating cell invasion-related molecules.
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DOI：
10.3892/ijo.29.1.73
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发表时间：
2006-07
影响因子：
5.2
通讯作者：
Koji Furukawa;Y. Kumon;H. Harada;S. Kohno;S. Nagato;Mikio Teraoka;Satoshi Fujiwara;Kou Nakagawa;K. Hamada;T. Ohnishi
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文献类型：
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作者：
Koji Furukawa;Y. Kumon;H. Harada;S. Kohno;S. Nagato;Mikio Teraoka;Satoshi Fujiwara;Kou Nakagawa;K. Hamada;T. Ohnishi
抑癌基因PTEN的功能缺失在高级别恶性胶质瘤中比在低级别胶质瘤中更常见。高级别胶质瘤的特点是具有极强的侵袭性，提示PTEN是细胞运动的重要调节因子之一，其编码基因的改变有助于肿瘤细胞更具侵袭性。为了阐明PTEN在脑胶质瘤侵袭中的作用，我们将野生型PTEN基因导入人恶性胶质瘤细胞系，并在模拟正常脑环境的活体脑片模型中研究其运动和侵袭活性。此外，我们还分析了PTEN在胶质瘤细胞中的转移所引起的生化和分子变化。体外迁移和化学侵袭实验表明，携带野生型PTEN基因的复制缺陷型腺病毒载体(Ad5CMV-PTEN)可显著抑制PTEN基因突变的胶质瘤细胞的迁移和侵袭活性。在器官型脑片模型中，胶质瘤球体与大鼠脑片共培养表明，Ad5CMV-PTEN转基因细胞不能侵袭周围的正常脑组织。将Ad5CMV-PTEN导入缺乏野生型基因产物的胶质瘤细胞系，可降低基质金属蛋白酶-2(MMP2)的表达水平，并抑制MMP2和MMP9的活性。相反，PTEN基因转移上调了TIMP-2mRNA的表达。在胶质瘤细胞系中导入PTEN基因可显著降低RAC-GTP和CDC42-GTP的水平，激活这些小分子GTP结合蛋白的形式，并降低粘着斑激酶的磷酸化水平。这些结果表明，PTEN通过两种方式抑制胶质瘤细胞的侵袭：抑制MMPs对细胞外基质的蛋白分解，以及通过灭活两个Rho家族GTP结合蛋白Rac和CDc42来调节胶质瘤细胞的迁移活性，使其运动能力减弱。
Loss of function of the tumor suppressor gene PTEN is more frequently encountered in high-grade malignant gliomas than in low-grade gliomas. High-grade gliomas are characterized by their extremely invasive behavior, suggesting that PTEN is one of the important regulators of cell motility and that alterations of its coding gene contribute to a much more invasive tumor cell phenotype. In order to clarify a role of PTEN in glioma invasion, we introduced the wild-type PTEN gene into human malignant glioma cell lines and investigated their motile and invasive activity in a brain slice model that presents circumstances analogous to normal brain conditions in vivo. In addition, we analyzed biochemical and molecular changes resulting from the transfer of PTEN in the glioma cells. Infection of recombinant replication-defective adenovirus vector containing the wild-type PTEN cDNA (Ad5CMV-PTEN) significantly inhibited the cell migration and invasion activities of PTEN-mutated glioma cell lines in in vitro migration and chemoinvasion assays. In an organotypic brain slice model, co-culture of glioma spheroids and rat brain slices demonstrated that Ad5CMV-PTEN transfected cells failed to invade surrounding normal brain tissues. Ad5CMV-PTEN transfer into the glioma cell lines lacking the wild-type gene product decreased the levels of matrix metalloproteinase (MMP)-2 mRNA and inhibited the enzymatic activities of MMP-2 and MMP-9. In contrast, mRNA expression of tissue inhibitor of metalloproteinase (TIMP)-2 was upregulated by the PTEN gene transfer. Introduction of PTEN gene in glioma cell lines markedly reduced the levels of Rac-GTP and Cdc42-GTP, activated forms of these small GTP-binding proteins, and decreased the phosphorylation levels of focal adhesion kinase. These results suggest that PTEN inhibits glioma cell invasion in two ways: suppressing proteolysis of the extracellular matrix by MMPs and modulating the migratory activity of glioma cells to a less motile nature by inactivating two Rho-family GTP-binding proteins, Rac and Cdc42.