Characterization of initiated cells in N-methylnitrosourea-induced carcinogenesis of the CNS in the adult rat.
Characterization of initiated cells in N-methylnitrosourea-induced carcinogenesis of the CNS in the adult rat.
复制标题
N-甲基亚硝基脲诱导成年大鼠中枢神经系统癌变过程中启动细胞的表征。
DOI：
10.1093/neuonc/3.2.99
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发表时间：
2001
期刊：
影响因子：
15.9
通讯作者：
ScholdJr,SC
中科院分区：
文献类型：
--
作者：
Kokkinakis,DM;Watson,ML;Honig,LS;Rushing,EJ;Mickey,BE;ScholdJr,SC
神经胶质瘤可能起源于多能性神经胶质瘤祖细胞的恶性转化，但由于缺乏代表成年动物这种疾病早期阶段的生物系统，研究导致神经胶质瘤的恶性转化的工具受到限制。为了表征产生胶质瘤的起始细胞，我们采用了甲基亚硝基脲（MNU）模型来诱导成年大鼠脑肿瘤（rush et al., 1998）。具体来说，我们从暴露于MNU 10周的正常大鼠大脑和暴露于MNU 15周的组织学异常大鼠大脑中分离和培养了转化（癌前）细胞。我们将它们与在相同条件下从对照动物身上培养的细胞进行了比较。根据培养细胞在胸腺小鼠体内的形态、免疫表型、核型、增殖能力和致瘤性进行分类。未经处理的正常大鼠脑培养物呈单层生长，具有正常的核型（42 X，Y），上皮样形态和缓慢的增殖能力（翻倍时间bb0 120 h）。相比之下，从暴露于mnu的动物的大脑中培养的细胞具有从正常到高度非整倍体的核型。非整倍体细胞系多层生长迅速（倍增时间<24 h），分化为星形细胞或少突胶质细胞形态和免疫组化染色谱，并在胸腺小鼠中产生肿瘤。具有轻微染色体畸变的起始细胞在高密度培养中呈现混合双极或三极形态，增殖迅速，但在胸腺小鼠中注射sc时表现出接触抑制，无法诱导肿瘤。一般来说，没有染色体畸变的细胞系上皮样形态最多，增殖缓慢（翻倍时间约为72小时），并保留严格的接触生长抑制。从对照组或mnu处理的大鼠培养的未分化的胶质祖细胞中，不同程度地表达了诸如vimentin、nestin和NG2蛋白聚糖等标记物，它们分别弱表达成熟星形胶质细胞或少突胶质标记物胶质纤维酸性蛋白或半乳糖苷。这些培养物在暴露于次级信使如二丁基环amp和/或生长因子如碱性纤维生长因子后，分化为双极性-三极性形态，同时成熟为GFAP+或GalC+表型。这些信使的持续刺激导致了终末分化和随后的刺激退出后死亡。这些结果提供的信息可能导致成人大脑中启动的癌前细胞的详细特征，并更好地了解胶质癌的发生。
Glial tumors may originate from the malignant transformation of multipotent glial progenitor cells, but tools to study malignant transformation leading to gliomas are limited by the lack of biological systems that represent early stages of this disease in adult animals. In order to characterize the initiated cells that give rise to gliomas, we have employed theN-methylnitrosourea (MNU) model for induction of brain tumors in adult rats (Rushing et al., 1998). Specifically, we have isolated and cultured transformed (premalignant) cells from normal-appearing brains of rats exposed to MNU for 10 weeks and from histologically abnormal brains of rats exposed to MNU for 15 weeks. We compared them with cells cultured from control animals under identical conditions. Cultured cells were classified according to their morphology, immunophenotype, karyotype, proliferation capacity, and tumorigenicity in athymic mice. Cultures from untreated normal rat brains grew as monolayers and had normal karyotypes (42 X,Y), epithelioid morphology, and slow proliferative capacity (doubling time >120 h). In contrast, cultured cells from brains of MNU-exposed animals had karyotypes that ranged from normal to highly aneuploid. Aneuploid lines grew rapidly in multilayers (doubling time <24 h), had differentiated astrocytic or oligodendroglial morphology and immunohistochemical staining profile, and yielded tumors in athymic mice. Initiated cells with minor chromosomal aberrations assumed mixed bipolar or tripolar morphologies in high density cultures, proliferated rapidly, but showed contact inhibition and failed to induce tumors when injected s.c. in athymic mice. In general, lines showing no evidence of chromosomal aberrations had the most epithelioid morphology, proliferated slowly (doubling time >72 h), and retained strict contact growth inhibition. The presumed undifferentiated glial progenitor cells in culture from either control or MNU-treated rats variably expressed markers such as vimentin, nestin, and NG2 proteoglycan, and they weakly expressed the mature astrocytic or oligodendroglial markers glial fibrillary acidic protein or galactocerbroside, respectively. These cultures differentiated to bipolar-tripolar morphology with concomitant maturation to a GFAP+ or GalC+ phenotype upon exposure to secondary messengers such as dibutyryl-cyclic-AMP and/or growth factors such as basic fibrillary growth factor. Continuous stimulation with these messengers resulted in terminal differentiation and consequent death upon withdrawal of the stimulus. These results provide information that could lead to detailed characterization of initiated, premalignant cells in the adult brain and to a better understanding of glial carcinogenesis.