CYSTINE-RICH GROWTH FACTOR FOR A TUMORIGENIC CELL LINE

小鼠C3H畸胎瘤来源的成脂细胞系1246 在规定的介质中进行脂肪分化的严格要求 胰岛素对这两个过程都有效。几种不同的胰岛素非依赖性细胞 这些线路都是孤立的。他们已经失去了区分的能力， 在他们的培养基中致癌和产生促进生长 和脂肪分化抑制活性。基于这些 结果提示，产生性细胞产生的因子 以自分泌方式起作用，并解释了表型的变化 在胰岛素非依赖性变体中观察到。此外，有人认为， 增长因素的生产是造成较低增长的原因。 致瘤胰岛素非依赖性细胞系的因子需求。在……里面 为了研究这些可能性，我们已经分离出一个高度 称为PC的致癌胰岛素非依赖性细胞系。结果发现， 高致瘤性PC细胞系依赖于其 在其自身文化中发现的一种促进生长的活动的增殖 5~6成熟。被称为PCDGF的生长因子被提纯为均一种 PC细胞条件培养液的三层析步骤。这个 纯因子是一种90 kDa的糖蛋白。对PCDGF进行了部分测序 表明属于一类新的富含双半胱氨酸的蛋白质 未知的生物活性。因为这是第一次描述 这类新蛋白质的生物学作用以及由于该因子 是由一种高致瘤性的细胞系产生的，建议进一步 描述这种增长的作用、作用机制和结构 在细胞、生化和分子水平上的因素。实验 建议：克隆PC衍生生长因子的cDNAs； 研究其在细胞系中的表达水平 在正常和肿瘤中，肿瘤的致癌性质的增加程度 组织：检测PCDGF基因转染细胞的表型 在正义和反义取向上，并考察其 体外生物活性及其在体内致瘤性中的作用 表达PCDGF的细胞。这些研究将使我们能够调查 详细介绍了一种新的生长因子的生物学特性，并进一步说明了我们 对自分泌机制在获得性脑损伤中作用的认识 中胚层的致瘤性和分化特性丧失 衍生的细胞系。

Mouse C3H teratoma-derived adipogenic cell line 1246 which grows and undergoes adipose differentiation in defined medium strictly requires insulin for both processes. Several variant insulin-independent cell lines were isolated. They have lost their ability to differentiate, have become tumorigenic and produce in their culture medium growth promoting and adipose differentiation inhibitory activities. Based on these results, it was suggested that the factors produced by the producer cells acted in an autocrine fashion and accounted for the change of phenotype observed in the insulin-independent variant. Moreover, it was assumed that growth factor production was responsible for the lesser growth factor requirement of tumorigenic insulin-independent cell lines. In order to examine these possibilities, we have isolated a highly tumorigenic insulin-independent cell line called PC. It was found that the highly tumorigenic PC cell line becomes dependent for its proliferation on a growth promoting activity found in its own culture medium. The growth factor called PCDGF was purified to homogeneity by a three chromatography step from the conditioned medium of PC cells. The pure factor is a 90 kDa glycoprotein. PCDGF was partially sequenced and shown to belong to a novel class of double cysteine rich proteins of unknown biological activity. Since it is the first characterization of a biological role for this novel class of protein and since the factor is produced by a highly tumorigenic cell line, it is proposed to further characterize the role, mechanism of action and structure of this growth factor at the cellular, biochemical and molecular levels. Experiments are proposed: to clone cDNA for the PC derived growth factor; to investigate the level of its expression in cell lines presenting increasing degree of tumorigenic properties and in normal and neoplastic tissues; to determine the phenotype of cells transfected with PCDGF cDNA in the sense and anti sense orientation; and to investigate its biological activity in vitro and its role in the in vivo tumorigenicity of cells expressing PCDGF. These studies will enable us to investigate in detail the biology of a novel growth factor and also to further our understanding in the role of autocrine mechanism in acquisition of tumorigenicity and loss of differentiation properties of mesodermal derived cell lines.