Shuler C, Kurian P, French B T, Noyes I, Sital N, Hollering J, Trewyn R W, Schuller D, Milo G E
Department of Physiological Chemistry, College of Medicine, Ohio State University, Columbus 43210.
Teratog Carcinog Mutagen. 1990;10(1):53-65. doi: 10.1002/tcm.1770100107.
The distribution of heterogeneous cell types within human tumors was examined, and the biological behavior of tumors and different tumor cell lines was evaluated following implantation into surrogate hosts. In situ hybridization and immunohistochemistry were used to examine the expression of oncogenes and localization of the squamous cell carcinoma cell surface-associated antigens. Increased levels of H-ras mRNA and p21 protein were present in six tumors, but enhanced c-myc mRNA expression was observed in just two tumors. The distribution of oncogene mRNA and SCC antigen-positive cells was not uniform throughout the tumor. Isolation of cells from the tumors was accomplished by cell culture, growth in soft agar, and growth in the nude mouse. One nontumorigenic immortalized cell line, SCC-83-01-82, isolated by passage through soft agar, was treated with 50 micrograms/ml of methyl methane sulfonate (MMS). These MMS-converted cells subsequently expressed a tumorigenic phenotype. In situ hybridization of the tumors that developed in nude mice revealed increased c-myc and H-ras mRNA expression. Serial passage of the MMS-converted tumors in vivo was accompanied by consistent enhanced c-myc expression. However, the levels of H-ras and keratin mRNA expression decreased with passage in vitro. Northern blot analysis of c-myc and H-ras mRNA levels from the original SCC cell line showed no change in expression following MMS treatment. The data suggest that SCC-83-01-82 is a premalignant cell line established from a mixed cell population in the tumor mass. It can be converted to a malignant phenotype by treatment with MMS, and the persistence of malignancy is under molecular control other than changes in the level of c-myc and ras gene expression.
研究了人类肿瘤中异质细胞类型的分布，并在将肿瘤和不同肿瘤细胞系植入替代宿主后评估了它们的生物学行为。采用原位杂交和免疫组织化学方法检测癌基因的表达及鳞状细胞癌细胞表面相关抗原的定位。6个肿瘤中存在H-ras mRNA和p21蛋白水平升高，但仅在2个肿瘤中观察到c-myc mRNA表达增强。癌基因mRNA和SCC抗原阳性细胞在肿瘤中的分布并不均匀。通过细胞培养、软琼脂生长和裸鼠生长从肿瘤中分离细胞。一个通过软琼脂传代分离得到的非致瘤性永生化细胞系SCC-83-01-82，用50微克/毫升的甲基磺酸甲酯（MMS）处理。这些经MMS转化后的细胞随后表现出致瘤表型。对在裸鼠中形成的肿瘤进行原位杂交显示c-myc和H-ras mRNA表达增加。MMS转化后的肿瘤在体内连续传代伴随着c-myc表达持续增强。然而，H-ras和角蛋白mRNA表达水平在体外传代时下降。对原始SCC细胞系的c-myc和H-ras mRNA水平进行Northern印迹分析表明，MMS处理后表达无变化。数据表明，SCC-83-01-82是从肿瘤块中的混合细胞群体建立的癌前细胞系。它可以通过MMS处理转化为恶性表型，并且恶性的持续存在受分子控制，而非c-myc和ras基因表达水平的变化。
