Glial cell differentiation and glioma formation

拟议研究的总体目标是阐明负责神经胶质细胞分化的分子机制，并利用参与分化的信号传导成分作为最终治疗低级别胶质瘤的工具。 我们小组先前的工作确定了自分泌环PDGF信号传导导致培养物中星形胶质细胞向胶质祖细胞的去分化，以及小鼠中低级别胶质瘤的形成。 PDGF受体酪氨酸激酶活性的药理学阻断导致细胞恢复为分化的星形胶质细胞样细胞。 因此，我们假设已知促进分化的药物将逆转肿瘤发生表型。 我们在原代少突胶质细胞中的研究已经确定了参与少突胶质细胞分化的关键信号蛋白，包括Fyn、p190 RhoGAP、Rho和Cdk抑制剂。 因此，我们打算直接测试这些信号分子的能力，以调节神经胶质细胞分化的文化，和少突胶质细胞瘤形成的小鼠和人类，如下：目的1：为了确定Src家族激酶的作用，Rho通路，Cdk抑制剂和Rb家族成员在神经胶质细胞分化的文化。 用编码Fyn、p190 RhoGAP、Rho、p21和p27的wt和突变形式的RCAS载体感染表达GFAP-PDGF以及nestin-PDGF的细胞，并测定对细胞生长和分化的影响。目的2：探讨Src家族激酶、Rho通路、Cdk抑制剂和Rb家族成员在少突胶质细胞瘤形成中的作用。 转基因小鼠将用于确定上述分子在小鼠肿瘤形成中的作用。目的3：分析人少突胶质细胞瘤中上述分子和通路的活性，以验证所提出的实验模型。 将测定上述蛋白在人神经胶质瘤肿瘤样品中的活性。

The overall goal of the proposed research is to elucidate the molecular mechanisms responsible for glial cell differentiation and to exploit the signaling components involved in differentiation as tools for the ultimate treatment of low grade gliomas. Previous work by our group established that autocrine loop PDGF signaling causes a dedifferentiation of astrocytes to glial progenitors in culture, and formation of low- grade gliomas in mice. Pharmacologic blockade of PDGF receptor tyrosine kinase activity causes the cells to revert to differentiated astrocyte-like cells. We therefore hypothesize that agents that are known to promote differentiation will reverse the tumorigenic phenotype. Our studies in primary oligodendrocytes have identified key signaling proteins, including Fyn, p190RhoGAP, Rho, and Cdk inhibitors, that are involved in oligodendrocyte differentiation. We therefore intend to directly test the ability of these signaling molecules to regulate glial cell differentiation in culture, and oligodendroglioma formation in mice and humans, as follows: Aim 1: To determine the role of Src family kinases, the Rho pathway, Cdk inhibitors and Rb family members in glial cell differentiation in culture. GFAP-PDGF as well as nestin-PDGF expressing cells will be infected with RCAS vectors encoding wt and mutant forms of Fyn, p190RhoGAP, Rho, p21 and p27 and the effects on growth and differentiation of the cells will be determined. Aim 2: To determine the role of Src family kinases, the Rho pathway, Cdk inhibitors and Rb family members in oligodendroglioma formation in vivo. Transgenic mice will be utilized to determine the role of the above molecules in tumor formation in mice. Aim 3: To analyze human oligodendrogliomas for activity of the above molecules and pathways in order to validate the proposed experimental models. The activity of the above proteins in human glioma tumor samples will be determined.