Damjanov I, Horvat B, Gibas Z
Department of Pathology and Cell Biology, Jefferson Medical College, Thomas Jefferson University Philadelphia, Pennsylvania.
Lab Invest. 1993 Feb;68(2):220-32.
Germ cell tumors are empirically divided into seminomas and nonseminomatous germ cell tumors (NSGCT). Some authorities consider seminomas to be the precursors of NSGCT, whereas others consider them as distinct and unrelated neoplasms. Here, we report that the human NSGCT-derived stem cell line, NCCIT has hybrid features of seminoma and embryonal carcinoma, and suggest that this cell line could be useful for studying the relationship of seminoma to NSGCT.
NCCIT, a developmentally pluripotent permanent cell line derived from a mediastinal NSGCT was karyotyped and characterized morphologically, immunochemically, and biochemically. The cells were grown under standard tissue culture conditions and were also exposed to retinoic acid to induce differentiation.
The dividing NCCIT stem cell populations consist of vimentin-positive, keratin-negative cells that do not express desmoplakin or cadherin E (uvomorulin) and are not interconnected with one another. These cells have a high nucleocytoplasmic ratio and contain few cytoplasmic organelles, except for free ribosomes and a small number of mitochondria. Lacto- and globoseries oligosaccharide antigens recognized with antibodies to murine stage specific antigens 1, 3 and 4 (SSEA-1, SSEA-3 and SSEA-4), and human teratocarcinoma mucin-like antigen TRA-1-60 and TRA-1-81 are coexpressed on the cell membranes of a considerable number of stem cells. On most cells alkaline phosphatase can be detected by enzyme histochemistry. The placental isoenzyme of alkaline phosphatase was demonstrated by Western blotting in cell extracts. The liver/bone/kidney isoenzyme of alkaline phosphatase is immunochemically detected on 40% of cells. The culture supernatants also contain chorionic gonadotropin and alpha-fetoprotein, presumably derived from trophoblastic and yolk sac-like cells. The cells are hyperdiploid (chromosome range from 54 to 64) and show prominent structural chromosomal aberrations, mostly deletions and isochromosomes. Retinoic acid treatment inhibited the growth of NCCIT cells and induced stem cell differentiation into keratin, glial fibrillary acid protein, and neurofilament-positive somatic cells. The differentiation was associated with the disappearance of oligosaccharide surface antigens typical of the undifferentiated stem cells; a loss of proteins typical of undifferentiated cells and the appearance of new proteins; and the deposition of extracellular matrix.
NCCIT is a developmentally pluripotent cell line that can differentiate into derivatives of all three embryonic germ layers (i.e., ectoderm, mesoderm, and endoderm) and extraembryonic cell lineages. We suggest that this cell line could be a malignant replica of human cleavage stage embryonic cells with features intermediate between seminoma and embryonal carcinoma.
根据经验，生殖细胞肿瘤分为精原细胞瘤和非精原细胞性生殖细胞肿瘤（NSGCT）。一些权威人士认为精原细胞瘤是NSGCT的前体，而另一些人则认为它们是不同的、不相关的肿瘤。在此，我们报告源自人NSGCT的干细胞系NCCIT具有精原细胞瘤和胚胎癌的混合特征，并表明该细胞系可能有助于研究精原细胞瘤与NSGCT之间的关系。
对源自纵隔NSGCT的具有发育多能性的永久细胞系NCCIT进行核型分析，并从形态学、免疫化学和生物化学方面进行表征。细胞在标准组织培养条件下生长，并且也暴露于视黄酸以诱导分化。
正在分裂的NCCIT干细胞群体由波形蛋白阳性、角蛋白阴性的细胞组成，这些细胞不表达桥粒斑蛋白或E-钙黏蛋白（尿膜素），并且彼此不相互连接。这些细胞具有高核质比，除了游离核糖体和少量线粒体之外，几乎没有细胞质细胞器。用抗小鼠阶段特异性抗原1、3和4（SSEA-1、SSEA-3和SSEA-4）的抗体以及人畸胎癌黏蛋白样抗原TRA-1-60和TRA-1-81识别的乳糖和球系列寡糖抗原在相当数量的干细胞细胞膜上共表达。在大多数细胞上，通过酶组织化学可检测到碱性磷酸酶。通过蛋白质印迹法在细胞提取物中证实了碱性磷酸酶的胎盘同工酶。在40%的细胞上通过免疫化学检测到碱性磷酸酶的肝/骨/肾同工酶。培养上清液中还含有绒毛膜促性腺激素和甲胎蛋白，推测它们源自滋养层细胞和卵黄囊样细胞。这些细胞是超二倍体（染色体范围为54至64），并显示出明显的结构染色体畸变，主要是缺失和等臂染色体。视黄酸处理抑制了NCCIT细胞的生长，并诱导干细胞分化为角蛋白、胶质纤维酸性蛋白和神经丝阳性的体细胞。这种分化与未分化干细胞典型的寡糖表面抗原的消失、未分化细胞典型蛋白质的丢失以及新蛋白质的出现以及细胞外基质的沉积有关。
NCCIT是一种具有发育多能性的细胞系，可分化为所有三个胚胎胚层（即外胚层、中胚层和内胚层）以及胚外细胞谱系的衍生物。我们认为该细胞系可能是具有介于精原细胞瘤和胚胎癌之间特征的人卵裂期胚胎细胞的恶性复制品。
