Transformation related proteins of human brain tumors in vivo and in vitro.

在本课题中，我们在体外和体内研究了人脑肿瘤合成的转化因子和/或生长促进因子。在人胶质瘤组织培养基中，集落形成因子(s)分子量小于20Kd。兔抗低分子部分抗体与大于50Kd的高分子蛋白反应，在培养基中不能检测低分子蛋白。另一方面，该抗体与胶质瘤细胞提取物中的17Kd蛋白发生反应。电分离得到17Kd蛋白，并免疫新西兰大白兔。用免疫亲和柱层析法从抗血清中获得单抗IgG抗体。我们发现细胞内17Kd蛋白在免疫学上与血小板衍生生长因子（PDGF）的一个单体相同。17Kd单体迅速组装成更高分子量的形式，其中56Kd蛋白是最稳定和最占优势的。17Kd单体…更多的蛋白未被磷酸化，而组装的形式全部被磷酸化。在人胶质瘤细胞培养培养基中检测到56Kd蛋白。从胶质瘤细胞中纯化的56Kd蛋白可诱导培养细胞形成皱褶膜并重组肌动蛋白纤维。人类脑肿瘤是通过外科手术获得的，保存在-70°c的环境中，直到使用为止，肿瘤中含有不同数量的pdgf相关蛋白，从单体形式到组装形式。PDGF相关蛋白的表达量与肿瘤类型（如良恶性星形细胞瘤、成神经管细胞瘤、脑膜瘤、神经瘤和神经细胞瘤）无关。在每种肿瘤类型中，使用BrdU单克隆抗体的体内s期标记技术测量具有较高增殖活性的肿瘤比具有低增殖活性的肿瘤具有更高数量的pdgf相关蛋白。我们认为脑肿瘤合成和分泌pdgf相关蛋白是维持肿瘤潜能最重要的蛋白之一。少

In the present research project, we have studied on transforming and/or growth promoting factors synthesizedby human brain tumors in vitro and in vivo.In tissue culture media of human glioma, colony-forming factor (s) was low molecular weight less than 20Kd. The rabbit antibody against to the low molecule fraction reacted with high molecule proteins over 50Kd and unable to detect low molecule proteins in culture media. On the other hand, the antibody reacted with 17Kd protein in extracts of glioma cells. The 17Kd protein was electrophereficauy isolated and was immunized to New Zealand white rabbits. The monospecic polyclonal IgG antibody was obtained from the antiserum using immunoaffiny colum chromatography. It was realized that the intracellular 17Kd protein was immunologically identical to a monomer of pletelet derived growth factor (PDGF). The 17Kd monomer promptly assembled to higher molecular weight forms, in which 56Kd protein was the most stable and predominant The 17Kd monomer … More protein was not phosphorylated, while the assembled forms were all phosphorylated. The 56Kd protein was detectable in media of human glioma cell cultures. The 56Kd protein purified from glioma cell homogenates induced cultured cells to forming ruffle membranes and reorganizing actin fibers. Human brain tumors, which was surgically obtained and stored in -70^0C until use, included variuos amounts of PDGF-related proteins as a monomeic form to assembled forms. The amounts of PDGF related proteins were not corelated to tumor types, such as benign or malignt astrocytoma, medulloblastoma, meningioma, neurinoma and neurocytoma. In each tumor type, the tumors possesing higher proliferative activity, which was measured with in vivo S-phase labelling technique using BrdU monoclonal antibody, tended to having higher amounts of PDGF-related proteins than tumors with low proliferative activity.We presume that brain tumors synthesize and secrete PDGF-related proteins as one of the most essential proteins for keeping neoplastic potentials. Less