Basic study on the differentiation induction of human germ cell tumors and its clinical application

1.六亚甲基双乙酰胺(HMBA)对体外培养的人胚胎性癌细胞株(NEC14)具有诱导分化作用。分化伴随着人类主要组织相容性抗原(HLA-A、B、C)的显著诱导和阶段特异性胚胎抗原的变化(由SSEA-1^-/SSEA-3^+转变为SSEA-1^+/SSEA-3^-)。结论：1.分化后的NEC14细胞表达间充质相关分子Vimentin和tenascin，HMBA可诱导其分化为胚胎中胚层的某些间充质成分。在未分化的NEC14细胞中，N-myc的表达水平很高，但在HMBA诱导后，N-myc的表达水平短暂下降到不到原始水平的1/10。为了研究N-myc基因在NEC14细胞分化中的作用，我们建立了几个表达外源N-myc基因的NEC14转化子。它们具有较短的群体倍增时间、较高的细胞接种效率和致瘤潜能。血清神经元特异烯醇化酶(NSE)水平可作为诊断未成熟畸胎瘤和无性细胞瘤的新指标。从人畸胎癌细胞系PA-1出发，建立了一个在体外多细胞球体内产生明显神经花环的克隆系。该细胞株表达A2B5、HNK-1、NC-1、NSE、S-100蛋白和波形蛋白等神经外胚层抗原。这些花环显示明显的极化和重叠的细胞外基质成分的沉积，包括层粘连蛋白、IV型胶原、硫酸乙酰肝素蛋白多糖和肌腱蛋白。

1. A plupribotent human embryonal carcinoma cell line (NEC14) could be induced to differentiate morphologically by treatment with 10^<-2>M N, N'-hexamethylene-bis-acetamide (HMBA) in vitro. The differentiation accompanied the marked induction of human 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^-). Differentiated NEC14 cells expressed mesenchym-associated molecules, vimentin and tenascin ; thus HMBA can induce these cells to certain mesenchymalle elements of embryonal mesoderm.2. The level of N-myc expression was high in undifferentiated NEC14 cells, but decreased transiently to less than 1/10 of the original level after the HMBA induction. To investigate the role of N-myc gene in the NEC14 cell differentiation, we established several NEC14 transformants expressing exogenous N-myc genes. They showed shorter population doubling time, increased plating efficiency and tumorigenic potential.3. The level of neuron specific enolase (NSE) in serum was found to be a novel diagnostic marker for immature teratomas and dysgerminomas.4. From the human teratocarcinoma line PA-1, we established a clonal line that produced a distinct neural rosettes within in vitro multicellular spheroids. This line expressed neuroectodermal antigens such as A2B5, HNK-1 and NC-1, NSE, S-100 protein and vimentin. These rosette showed a strikingly polarized and overlapped deposition of extracellular matrix components including laminin, type IV collagen, heparan sulfate proteoglycan and tenascin.