DIFFERENTIALLY EXPRESSED GENE PRODUCTS IN GLIOMAS

人类胶质瘤的致癌作用已被描述为通过 基因损伤的积累，最终导致激活 原癌基因和/或肿瘤抑制基因功能丧失。 这一假设是基于之前的研究，这些研究已经描述了 表皮生长因子受体基因的扩增和缺失 胶质瘤中与9、10和17号染色体相关的序列。这 该项目旨在本地化和确定推定的 位于染色体上的胶质母细胞瘤相关肿瘤抑制基因 10.多项研究表明，染色体的缺失 10个等位基因是在 胶质母细胞瘤(GBM)。为了进一步检验这一观察结果，我们重新- 用微细胞技术将人10号染色体导入两种胶质母细胞瘤细胞系 介导的染色体转移，并表现出戏剧性的丢失 杂交细胞的致瘤表型。杂交细胞表现出一种损失 在软琼脂中生长的能力，降低了饱和密度 单层，不能在裸鼠体内形成肿瘤。可持续发展战略 这一功能方法证明了GTS基因在 10号染色体。我们分离GTS基因的长期目标包括使用 两种不相互排斥的方法：分割10号染色体，以及 要将各种定义的片段重新插入GBM细胞以进行区域定位 通过检测GTS基因对肿瘤的功能性抑制作用。我们的努力 将特别针对区域10q22至10qter，其中 初步证据表明，GTS基因可能存在。另外， 消减杂交将在cDNA表达文库上进行 找出因基因重排而差异表达的基因 将10号染色体插入GBM细胞。差异表达的 然后，基因产品将根据其基因结构进行表征， 表达模式、序列和基因结构，以便最终 检查他们的职能角色。此外，这两种方法可以是 结合以确定映射到特定染色体区域的基因 兴趣，并以不同方式表达。这些结果应该会增加 我们对神经胶质细胞特定基因改变的理解 然后可能为我们提供新的诊断标记物或特异性 人脑胶质瘤治疗干预的靶点。

The oncogenesis of human gliomas has been described to occur through the accumulation of genetic damage that eventually leads to the activation of proto-oncogenes and/or the loss of function of tumor suppressor genes. This hypothesis is based on previous studies that have described amplification of epidermal growth factor receptor gene and losses of sequences associated with chromosomes 9, 10, and 17 in gliomas. This project is directed at the localization and identification of a putative glioblastoma-associated tumor suppressor (GTS) gene located on chromosome 10. Several investigations have demonstrated that deletion of chromosome 10 alleles are the most frequent genetic alteration observed in glioblastomas (GBMs). To further examine this observation, we have re- inserted human chromosome 10 into two glioblastoma cell lines by micro-cell mediated chromosomal transfer and have demonstrated a dramatic loss of the tumorigenic phenotype of the hybrid cells. The hybrid cells exhibit a loss of their ability to grow in soft agarose, a decreased saturation density in monolayer, and failure to form tumor in nude animals. The utilization of this functional method demonstrates the presence of a GTS gene on chromosome 10. Our long-term goal to isolate the GTS gene involves the use of two non-mutually exclusive approaches: to fragment chromosome 10, and to re-insert the various defined pieces into GBM cells to regionally locate the GTS gene by assaying for functional tumor suppression. Our efforts will particularly be directed towards the region 10q22 to 10qter, where preliminary evidence suggests the GTS gene may reside. Additionally, subtractive hybridizations will be performed on cDNA expression libraries to identify genes which are differentially expressed as a result of re- insertion of chromosome 10 into GBM cells. The differentially expressed gene products will then be characterized for their gene structure, expression patterns, sequence, and gene structure, in order to eventually examine their functional roles. Furthermore, these two approaches can be combined to identify genes which map to specific chromosomal regions of interest and are differentially expressed. These results should increase our understanding of the specific genetic alterations involved in glial oncogenesis and may then provide us with new diagnostic markers or specific targets for therapeutic intervention in human gliomas.