The Effects of TGF-Beta on the Tumor Proliferation and Bone Resorption by Human Squamous Cell Carcinoma (S. C. C.)

研究了转化生长因子-β(TGF-β)对人口腔鳞癌细胞株HSC-2、HSC-3和HSC-4的作用。尽管这些细胞系对表皮生长因子同样敏感，但对转化生长因子-β的反应是不同的。加入转化生长因子-β对HSC-4的细胞生长和(~3H)-胸腺嘧啶核苷掺入有剂量依赖性的抑制作用，而对HSC-2和HSC-3的生长抑制作用不明显。并观察HSC-2、HSC-3、HSC-4对裸鼠颅骨的骨吸收作用。HSC-2和HSC-3能引起裸鼠颅骨的骨吸收，而HSC-4不能。Scatchard对转化生长因子-β结合的分析表明，所有鳞癌细胞株都具有相似的结合特性，这两类结合部位与转化生长因子-β结合。对细胞表面受体的亲和标记发现有两条主要的亲和交联带，MRs分别为65 kDa(I型)和280 kDa(III型)。在所有被检测的鳞状细胞癌细胞系中都观察到伴随的85 kDa条带的丢失(II型)。这些细胞系的I型受体的数量是不同的：即HSC-4的I型受体比HSC-2，3的I型受体相对丰富。这些结果表明，SCCC细胞的骨吸收与转化生长因子-β对细胞生长的影响有关，这种作用可能是由I型受体介导的。

The effects of transforming growth Factor-beta (TGF-beta) on three human oral squamous cell carcinoma cell lines, HSC-2, 3, and HSC-4, were investigated. Although these cell lines were equally sensitive to epidermal growth factor, responses to TGF-beta were variable. Dose-dependent inhibition of cell growth and (^3H)-thymidine incorporation of HSC-4 was observed by addition of TGF-beta, whereas growth inhibitory effects on HSC-2 and HSC-3 were marginal. Also the bone resorptions at nude mice calvaria by HSC-2, 3, and HSC-4, were investigated. HSC-2 and HSC-3 were able to cause bone resorption of the nude mice calvaria, whereas HSC-4 was not. Scatchard analysis of the binding of TGF-beta suggested that all squamous cell carcinoma cell lines have similar binding properties, which two classes of binding sites for TGF-beta. Affinity labeling of ^<125>I-TGF-beta to cell surface receptors revealed the two major affinity cross-linked bands with M_rs of 65 kDa (typeI) and 280 kDa (type III). A concomitant loss of 85 kDa band (type II) was observed in all squamous cell carcinoma cell lines examined. The numbers of type I receptors of these cell lines are variable : That is type I receptors of HSC-4 are comparably more abundant than those of HSC-2,3. These results indicate that bone resorption by S.C.C. cell lines is related to TGF-beta's effect on cell growth of the cell lines and that these effects may be mediated by type I receptors.