EXPRESSION OF TRANSFORMING GROWTH FACTOR BETA IN RHABDOMYOSARCOMA

我们发现横纹肌肉瘤表现出持续高水平的转化生长因子-β1， 和较小程度的转化生长因子β3，但缺乏转化生长因子β2蛋白。 体内免疫组织化学染色。我们还检测到不同水平的 培养上清液中转化生长因子-β蛋白的合成 横纹肌肉瘤细胞与水貂肺成纤维细胞(CCL-) 生物测定法和酶联免疫吸附试验法。此外，所有的均方根都表达了变量 转化生长因子-β1基因在体外的表达水平。这些数据，与我们的 转化生长因子-β抑制RMS细胞分化的研究进展 以及已知的转化生长因子-β对正常肌肉发生的抑制作用 向我们提出了转化生长因子-β在人类RMS中的作用。我们已经研究过 人参皂甙对RMS细胞转化生长因子-β1基因表达的影响 5-氮胞苷(AZA)，一种导致分化和抑制 细胞在RMS中生长，发现有2个RMS系细胞生长增加。然后我们 决定研究与其他药物是否有类似的变化 已知会导致分化和生长抑制，或生长抑制 单独，并选择一个RMS细胞系(RD)和3个额外的药物，即， 维甲酸、TPA和阿糖胞苷。转化生长因子-2的可能作用 在这个RMS细胞系的生长和分化中的β将是 以下列方式追求：(1)表达和亲和力的水平 其受体的转化生长因子-β将在治疗前后进行研究 上述试剂，通过结合试验和PAGE的细胞裂解物与 125I-转化生长因子-β1.(2)使用抗转化生长因子-β封闭抗体 以确定他们的作用是否与转化生长因子水平有关- Beta1。(3)将进行核转录分析，以评估是否 转化生长因子-β1基因水平升高是由于转录增加所致。 而不是减少营业额。(4)转化生长因子-β蛋白水平 评估以确定它们是否与信使核糖核酸水平平行。

We found that rhabdomyosarcomas show consistently high levels of TGF-beta1, and to a lesser extent TGF-beta3, but lack TGF-beta2 protein by immunohistochemical staining in vivo. We also detected variable levels of TGF-beta protein synthesis in conditioned media of cultured rhabdomyosarcoma (RMS) cells with the mink lung fibroblast (CCL-64) bioassay and the ELISA method. Furthermore, all RMS expressed variable levels of TGF-beta1 mRNA in vitro. These data, in combination with our previous data of TGF-beta-induced inhibition of RMS cell differentiation in vitro, and the known inhibitory effect of TGF-beta in normal myogenesis have suggested to us a role of TGF-beta in human RMS. We have studied levels of TGF-beta1 mRNA expression in RMS cell lines after treatment with 5-azacytodine (AZA), an agent that causes differentiation and inhibition of cell growth in RMS, and found them increased in 2 RMS lines. We then decided to study if there were similar changes with other agents that are known to cause differentiation and growth inhibition, or growth inhibition alone, and selected one RMS cell line (RD) and 3 additional agents, i.e., retinoic acid, TPA, and cytosine arabinoside. The possible role of TGF- beta in the growth and differentiation of this RMS cell line will be pursued in the following ways: (1) Levels of expression and affinity of TGF-beta for its receptors will be studied before and after treatment with the above agents, by binding assays and PAGE of cell lysates incubated with 125I-TGF-beta1. (2) Anti-TGF-beta blocking antibodies will be used along with the agents to determine if their action is linked to levels of TGF- beta1. (3) Nuclear transcription assays will be performed to evaluate if the elevated TGF-beta1 mRNA levels are due to increased transcription rather than decreased turnover. (4) TGF-beta protein levels will be evaluated to determine if they parallel the levels of mRNA.