Reguratory mechanisms in growth and differentiation of human embryonal carcinoma --- a model of human embryo.

10 μ M HMBA可诱导人胚胎癌细胞株NEC-14发生形态学分化<-2>。为了阐明分化谱系，我们研究了细胞表面抗原，凝集素结合位点，中间丝，细胞外基质和分泌蛋白的变化。抗原表达的最明显变化是主要组织相容性抗原HLA-A、B、C的诱导，以及阶段特异性胚胎抗原从SSEA-1^-/SSEA-3^+到SSEA-1^+/SSEA-3^-的变化。波形蛋白（Vimentin）是一种间充质中间纤维，只有在分化后才能检测到，提示HMBA诱导NEC-14细胞分化为胚胎中胚层的间充质成分。2、检测了NEC-14细胞中几种细胞癌基因的表达。N-myc的表达水平在未分化的细胞中最高，但在HMBA处理后不久短暂下降至原始水平的1/10以下。建立了几个组成型表达外源N-myc基因的NEC-14转化子。与亲本NEC-14细胞相比，这些转化子表现出不同的特性，例如更高的平板接种效率、更短的群体倍增时间和更高的致瘤潜能，表明额外的N-myc基因赋予细胞更高的转化状态。3、从人畸胎瘤细胞系PA-1中，我们建立了克隆系PA-1/NR，当作为体外多细胞球状体培养时，其稳定地产生神经细胞的独特细胞排列。玫瑰花结的形成伴随着细胞外基质成分，包括层粘连蛋白和IV型胶原蛋白的显著极化和重叠沉积。

1, A pluripotent human embryonal carcinoma cell line (NEC-14) could be induced to morphologically differentiate by treatment with 10^<-2> M HMBA in vitro. To clarify the differentiating lineage, we examined the changes in cell surface antigens, lectin-binding sites, intermediate filaments, and extracellular matrix and secreted proteins. The most distinct changes in antigen expression were the induction of major histocompatibility antigens, HLA-A,B,C, and the changes of stage-specific embryonic antigens, from SSEA-1^-/SSEA-3^+ to SSEA-1^+/SSEA-3^-. Vimentin, a well-known mesenchymal intermediate filament, could be detected only after the differentiation, suggesting that NEC-14 cells were differentiated by HMBA treatment into mesenchymal elements of embryonal mesoderm.2, The expression of several cellular oncogenes in the NEC-14 cells was also examined. The level of N-myc expression was the highest in undifferentiated cells, but decreased transiently shortly after the HMBA treatment to less than 1/10 of the original level. Several NEC-14 transformants constitutively expressing exogenous N-myc gene were established. Compared with the parental NEC-14 cells, these transformants show d quite different properties, for example, higher plating efficiency, shorter population doubling times, and increased tumorigenic potentials, indicating that additional N-myc genes confer the more transformed state on the cells.3, From the human teratocarcinoma cell line PA-1, we established a clonal line, PA-1/NR, that stably produced a distinct cellular arrangement of neural rosettes when cultured as in vitro multicellular spheroids. The rosette formation accompanied a strikingly polarized and overlapped deposition of extracellular matrix components including laminin and type IV collagen.