FACTORS PRODUCED BY TERATOMA VARIANTS AND IN VIVO TUMORIGENICITY

小鼠C3 H畸胎瘤衍生的脂肪形成细胞系1246，其生长并 在限定培养基中进行脂肪分化严格要求 胰岛素对这两个过程。 几种变异的胰岛素非依赖性细胞系 被隔离了 其中一个被称为1246-3A的被特别研究。 1246-3A细胞失去了分化能力， 致瘤的 它们产生促进生长的活动， 亲本细胞系1246的生长，并对其进行表征。 它 发现1246-3A细胞产生胰岛素相关因子（IRF）， 类似于胰腺胰岛素，起着自我刺激生长的作用， 因子; TGF-α样多肽（55 kDa和15 kDa）; TGF-β样 多肽和不同于TGF-α的13 kDa多肽生长因子 和TGF-β。 结果表明，TGF-α和β多肽和 13 kDa级分也抑制1246细胞的脂肪分化。 根据这些结果，可以认为脂肪 分化抑制剂抑制生产者的分化 细胞自分泌的方式，可以解释表型的变化 在胰岛素非依赖性变体1246-3A细胞中观察到。 而且是 可以假设生长因子的产生可以负责 致瘤胰岛素非依赖性细胞对生长因子的需求较少 线 为了检验这些可能性， 建议：1）分离高度致瘤的胰岛素非依赖性细胞系 从1246-3A细胞中分离出来 体外生长特性和细胞的能力 将检查合成内源性生长因子的细胞， 与1246和1246-3A细胞相比， 分子水平; 2）表征由所述细胞产生的生长因子， 高度致瘤性细胞系; 3）用 通过以下方法产生的各种多肽生长因子的表达载体 胰岛素非依赖性细胞系1246-3A（胰岛素、TGF-α、TGF-β） 并检查体外生长和分化特性， 转染细胞的体内致瘤性，和4）获得 从胰岛素非依赖性细胞系的回复突变细胞，并研究 它们的生长和分化特性，以确定是否 可恢复非致瘤性和分化能力。 这项研究将是我们调查的长期目标的一部分 与控制增长的因素的性质的定性有关， 间充质来源的细胞系的分化，并了解其 作用机制。

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 have been isolated. One of them called 1246-3A was particularly studied. 1246-3A cells have lost their ability to differentiate and have become tumorigenic. They produce growth promoting activities which can stimulate the growth of the parent cell line 1246 and which were characterized. It was found that 1246-3A cells produce an insulin related factor (IRF) similar to pancreatic insulin and acting as an autostimulating growth factor; TGF-alpha like polypeptides (55 kDa and 15 kDa); TGF-beta like polypeptide and a 13 kDa polypeptide growth factor different from TGF-alpha and TGF-beta. It was shown that the TGF-alpha and beta polypeptides and the 13 kDa fractions also inhibited adipose differentiation of 1246 cells. Based on these results, it can be suggested that the adipose differentiation inhibitors inhibit the differentiation of the producer cells in an autocrine fashion and can account for the change of phenotype observed in the insulin-independent variant 1246-3A cells. Moreover, it is possible to assume that growth factor production can be responsible for the lesser growth factor requirement of tumorigenic insulin-independent cell line. In order to examine these possibilities, several approaches are proposed: 1) to isolate highly tumorigenic insulin-independent cell lines from the 1246-3A cells. In vitro growth properties and the ability of the cells to synthesize of endogenous growth factors will be examined and compared to the ones of 1246 and 1246-3A cells both at the cellular and molecular levels; 2) to characterize the growth factor produced by the highly tumorigenic cell line; 3) transfect the parent cell lines with expression vectors for the various polypeptide growth factors produced by the insulin-independent cell line 1246-3A (insulin, TGF-alpha, TGF-beta) and examine the growth and differentiation properties in vitro, and tumorigenic properties in vivo of transfected cells, and 4) to obtain revertant cells from the insulin-independent cell lines and investigate their growth and differentiation properties, in order to determine if nontumorigenic properties and ability to differentiate can be recovered. This study will be part of the long-term objective of our investigations related to characterization of the nature of factors controlling growth and differentiation of mesenchymal derived cell lines and understanding their mechanism of action.