EXPRESSION OF TRANSFORMING GROWTH FACTOR BETA IN RHABDOMYOSARCOMA

我们发现横纹肌肉瘤显示出持续高水平的TGF-β 1， 和较小程度的TGF-β 3，但缺乏TGF-β 2蛋白， 体内免疫组织化学染色。 我们还检测到不同程度的 体外培养的人乳腺癌细胞条件培养基中TGF-β蛋白的合成 水貂肺成纤维细胞（CCL-64） 生物测定和ELISA方法。 此外，所有RMS表示变量 体外TGF-β 1 mRNA水平。 这些数据，结合我们的 以前的数据显示，TGF-β诱导的RMS细胞分化的抑制作用， 体外，和已知的抑制作用，TGF-β在正常的肌生成 向我们提示了TGF-β在人类RMS中的作用。 我们研究了 在用以下物质处理后RMS细胞系中TGF-β 1 mRNA表达水平 5-氮杂胞苷（AZA），一种引起分化和抑制 RMS细胞生长，发现2个RMS细胞系的细胞生长增加。 然后我们 决定研究其他药物是否有类似的变化， 已知引起分化和生长抑制，或生长抑制 单独使用，并选择一种RMS细胞系（RD）和3种另外的试剂，即， 视黄酸、TPA和阿糖胞苷。 TGF-β可能的作用 在这种RMS细胞系的生长和分化中， （1）表达水平和亲和力 将在治疗前后研究TGF-β对其受体的影响， 通过结合测定和与上述试剂孵育的细胞裂解物的PAGE， 125I-TGF-β 1。 (2)抗TGF-β阻断抗体将沿着 以确定它们的作用是否与TGF-β水平有关。 beta1 (3)将进行核转录试验，以评价是否 TGF-β 1 mRNA水平升高是由于转录增加 而不是减少营业额。 (4)TGF-β蛋白水平将 以确定它们是否与mRNA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.