Physiology and gene expression characteristics of carcinogen-initiated and tumor-transformed glial progenitor cells derived from the CNS of methylnitrosourea (MNU)-treated Sprague-Dawley rats.
Physiology and gene expression characteristics of carcinogen-initiated and tumor-transformed glial progenitor cells derived from the CNS of methylnitrosourea (MNU)-treated Sprague-Dawley rats.
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经甲基亚硝基脲 (MNU) 处理的 Sprague-Dawley 大鼠中枢神经系统衍生的致癌物引发和肿瘤转化的神经胶质祖细胞的生理学和基因表达特征。
DOI：
10.1093/jnen/63.11.1182
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发表时间：
2004
影响因子：
3.2
通讯作者：
Luo,Jianhua
中科院分区：
文献类型：
--
作者：
Kokkinakis,DemetriusM;Rushing,ElisabethJ;Shareef,MohammedM;Ahmed,MansoorM;Yang,Shuting;Singha,UjjalK;Luo,Jianhua
将正常成年Sprague-Dawley大鼠脑中的神经胶质祖细胞与从暴露于甲基亚硝基脲（MNU）的动物的明显正常脑中分离出的起始和恶性对应物进行比较。成纤维细胞生长因子-2（FGF-2）或血小板衍生生长因子（PDGF）-A或-B分别诱导正常祖细胞分化为前星形胶质细胞或少突胶质细胞形态，而这些因子的组合导致其终末分化为少突胶质细胞和衰老。相反，当用PDGF和/或FGF-2刺激时，起始的祖细胞不退出细胞周期。cDNA寡核苷酸阵列分析和RT-PCR验证显示，在肿瘤发生进展期间，生长因子/受体、PDGF-A、PDGFR-β、IGFR-1、IGF-1和-2、IL-6、MEGF-5、FRAG-1、IRS-2、HSPG和FGFR-1的表达早期上调/诱导，随后IGFBP-6、PDGF-α、FGFR-4A、c/ERB-A和FGFR-4、2和1的表达晚期增加。Western印迹分析表明，MNU暴露引起p21蛋白水平的逐步降低，Rb磷酸化的增加，AKT和CDK 2的激活，以及FGF受体的上调。双重免疫荧光标记显示FGFR 1、2和4的核共定位逐渐增加，在恶性细胞系中达到峰值。据推测，正常大鼠神经胶质祖细胞向起始状态的转变由IGF-1和2、IL-6以及受体PDGFR-β和FGFR-1、2和4的上调驱动。在这种状态下，细胞周期的失调涉及p21蛋白的减少，伴随着CDC 2的上调，以及Rb磷酸化的增加，这有利于FGFR-4和FRAG-1和2的表达和核转位。这些事件与AKT和RAS的进行性激活相关。恶性转化通过p21和PC 3的几乎消除、AP-1的诱导（JUN-B、c-JUN、FRA-1的上调）、NF-kB促存活途径的激活和TGF-β促凋亡途径的抑制而增强，这可能响应于神经生长因子（NGF）I-A和NGFI-B表达的变化。这些数据表明，MNU治疗引起大鼠脑恶性肿瘤的事件在很大程度上类似于人类继发性神经胶质恶性肿瘤的描述。
Glial progenitors from the brain of normal adult Sprague-Dawley rats were compared to their initiated and malignant counterparts that were isolated from apparently normal brains of animals exposed to methylnitrosourea (MNU). Fibroblast growth factor-2 (FGF-2) or platelet-derived growth factor (PDGF)-A or -B induced differentiation of normal progenitors to a pro-astrocytic or oligodendrocytic morphology, respectively, whereas the combination of these factors resulted in their terminal differentiation to oligodendrocytes and senescence. In contrast, initiated progenitors did not exit the cell cycle when stimulated with PDGF and/or FGF-2. cDNA oligoarray analysis and RT-PCR verification showed an early upregulation/ induction of growth factor/receptors, PDGF-A, PDGFR-β, IGFR-1, IGF-1 and -2, IL-6, MEGF-5, FRAG-1, IRS-2, HSPG, and FGFR-1, followed by a late increase in the expression IGFBP-6, PDGF-α, FGFR-4A, c/ERB-A, and FGFR-4, 2, and 1 during the tumorigenic progression. Western blot analyses demonstrated that MNU exposure caused progressive reduction of p21 protein levels, an increase of Rb phosphorylation, activation of AKT and CDK2, and upregulation of FGF receptors. Double immunofluorescence labeling showed progressive increase in nuclear colocalization of FGFR1, 2, and 4, which peaked in malignant lines. It is postulated that transition of normal rat glial progenitors to an initiated state is driven by IGF-1 and 2, IL-6, and the upregulation of the receptors PDGFR-β and FGFR-1, 2, and 4. Deregulation of the cell cycle in this state involves reduction of p21 protein, concomitant upregulation of CDC2, and an increase in Rb phosphorylation that favors expression and nuclear translocation of FGFR-4 and FRAG-1 and 2. These events are associated with progressive activation of AKT and RAS. Malignant transformation is enhanced by near elimination of p21 and PC3, induction of AP-1 (upregulation of JUN-B, c-JUN, FRA-1), activation of the NF-kB pro-survival pathway, and inhibition of the TGF-β pro-apoptotic pathway possibly in response to changes in the expression of nerve growth factor (NGF) I-A and NGFI-B. These data demonstrate that the events leading to malignancy in the rat brain in response to MNU treatment are to a great extent similar to those described for secondary glial malignancies in humans.