Isfort RJ, Cody DB, Kerckaert GA, LeBoeuf RA
Corporate Professional & Regulatory Services, The Procter & Gamble Company, Miami Valley Laboratories, Cincinnati, Ohio 45253-8707.
In Vitr Mol Toxicol. 1999;12(3):133-148.
The mitogenic growth and differentiation factor (GDFs) oncostatin M (OM), epidermal growth factor (EGF), fibroblast growth factor 4 (FGF-4), platelet-derived growth factor AA (PDGF AA), PDGF AB, and PDGF BB and the anti-mitogenic GDF, transforming growth factor beta one (TGF-beta1), were tested in the 7-day continuous exposure and 24-h transient exposure Syrian hamster embryo (SHE) cell transformation assay to determine their reversible and irreversible transforming potential. OM was negative while EGF, FGF-4, and PDGF AA were positive for statistically significant morphological transformation (MT) in the 7-day exposure SHE cell transformation assay. PDGF AB and PDGF BB (but not EGF, FGF-4, and PDGF AA) were positive for statistically significant MT in the 24-h transient exposure SHE cell transformation assays. TGF-beta1 was not only negative for the induction of MT in the 7-day and 24-h exposure SHE cell transformation assays, but suppressed the spontaneous background transformation response. Investigation of the transformation suppression potential of TGF-beta1 demonstrated that TGF-beta1 was able to irreversibly suppress the transformation potential of a variety of transforming agents including growth factors, Ames assay positive carcinogens, and Ames assay negative carcinogens. PDGF AA and PDGF BB were investigated to better understand the reversible and irreversible transformation response. Differences in the receptors activated, the proteins phosphorylated by the receptors, and immediate early gene expressed were observed in SHE cells treated with either PDGF AA or PDGF BB. Importantly, SHE cells treated with TGF-beta1 and PDGF BB, two GDFs, which modulate SHE cell transformation irreversibly, altered DNA methylation; PDGF AA did not demonstrate this effect. Together these data demonstrate that the SHE cell transformation assay can be utilized to evaluate the transformation potential and mechanism of activation of GDFs.
在7天连续暴露和24小时短暂暴露的叙利亚仓鼠胚胎（SHE）细胞转化试验中，对促有丝分裂生长和分化因子（GDFs）抑瘤素M（OM）、表皮生长因子（EGF）、成纤维细胞生长因子4（FGF - 4）、血小板衍生生长因子AA（PDGF AA）、PDGF AB和PDGF BB以及抗有丝分裂GDF转化生长因子β1（TGF - β1）进行了测试，以确定它们的可逆和不可逆转化潜力。在7天暴露的SHE细胞转化试验中，OM呈阴性，而EGF、FGF - 4和PDGF AA在统计学上具有显著形态转化（MT）为阳性。在24小时短暂暴露的SHE细胞转化试验中，PDGF AB和PDGF BB（但不是EGF、FGF - 4和PDGF AA）在统计学上具有显著MT为阳性。TGF - β1不仅在7天和24小时暴露的SHE细胞转化试验中对MT诱导呈阴性，而且还抑制了自发背景转化反应。对TGF - β1转化抑制潜力的研究表明，TGF - β1能够不可逆地抑制多种转化剂的转化潜力，这些转化剂包括生长因子、艾姆斯试验阳性致癌物和艾姆斯试验阴性致癌物。对PDGF AA和PDGF BB进行了研究，以更好地了解可逆和不可逆转化反应。在用PDGF AA或PDGF BB处理的SHE细胞中，观察到激活的受体、受体磷酸化的蛋白质以及表达的立即早期基因存在差异。重要的是，用TGF - β1和PDGF BB处理的SHE细胞，这两种GDFs不可逆地调节SHE细胞转化，改变了DNA甲基化；PDGF AA没有显示出这种效果。这些数据共同表明，SHE细胞转化试验可用于评估GDFs的转化潜力和激活机制。
