CRABP-II methylation: A critical determinant of retinoic acid resistance of medulloblastoma
CRABP-II methylation: A critical determinant of retinoic acid resistance of medulloblastoma
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CRABP-II 甲基化：髓母细胞瘤视黄酸耐药的关键决定因素
DOI：
10.1016/j.molonc.2011.11.004
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发表时间：
2012-02-01
影响因子：
6.6
通讯作者：
Liu, Jia
中科院分区：
文献类型：
--
作者：
Fu, Yuan-Shan;Wang, Qian;Liu, Jia
髓母细胞瘤细胞对全反式维甲酸（RA）治疗表现出不同的反应。然而，这种不同影响的潜在机制在很大程度上仍不清楚。在这项研究中，我们试图通过研究RA敏感（Med-3）和RA耐药（UW 228 -2和LTW 228 -3）髓母细胞瘤细胞中的RA信号成分来阐明RA耐药的分子基础。结果显示，RAR α/β/γ和RXR α/β/γ在三种细胞系中被发现。CRABP-I和CRABP-II的表达在Med-3细胞中观察到，当用RA处理时上调，但在LTW 228 -2和UW 228 -3细胞中不存在，无论RA处理如何。亚硫酸氢盐测序显示，在UW 228 -2和LTW 228 -3中，CRABP-H的启动子区有8个甲基化CG位点，但在Med-3细胞中没有。通过5-氮杂-2 '-脱氧胞苷的去甲基化恢复了CRABP-II表达。在恢复CRABP-II表达后，UW 228 -2和UW 228 -3细胞通过形成神经元样分化、突触素表达、β-III微管蛋白上调和凋亡对RA处理作出反应。此外，CRABP-II特异性siRNA降低了Med-3细胞中的RA敏感性。104例髓母细胞瘤组织芯片免疫组化染色显示CRABP-Ⅱ的表达模式为阴性（42.3%）、部分阳性（14.4%）和阳性（43.3%）。CRABP-II表达与突触素呈正相关（rs = 0.317; p = 0.001），但与CRABP-I表达无关（p > 0.05）。总之，CRABP-II的异常甲基化降低了CRABP-II的表达，这反过来又赋予髓母细胞瘤细胞中的RA抗性。CRABP-II表达或甲基化状态的测定可能使髓母细胞瘤和其他类型癌症患者的个性化RA治疗成为可能。(C)2011年欧洲生物化学学会联合会。Elsevier B. V.出版，保留所有权利。
Medulloblastoma cells exhibit varied responses to therapy by all-trans retinoic acid (RA). The underlying mechanism for such diverse effects however remains largely unclear. In this study, we attempted to elucidate the molecular basis of RA resistance through the study of RA signaling components in both RA-sensitive (Med-3) and RA-resistant (UW228-2 and LTW228-3) medulloblastoma cells. The results revealed that RAR alpha/beta/gamma and RXR alpha/beta/gamma were found in the three cell lines. Expression of CRABP-I and CRABP-II was seen in Med-3 cells, up-regulated when treated with RA, but was absent in LTW228-2 and UW228-3 cells regardless of RA treatment. Bisulfite sequencing revealed 8 methylated CG sites at the promoter region of CRABP-H in UW228-2 and LTW228-3 but not in Med-3 cells. Demethylation by 5-aza-2'-deoxycytidine recovered CRABP-II expression. Upon restoration of CRABP-II expression, both UW228-2 and UW228-3 cells responded to RA treatment by forming neuronal-like differentiation, synaptophysin expression, beta-III tubulin upregulation, and apoptosis. Furthermore, CRABP-II specific siRNA reduced RA sensitivity in Med-3 cells. Tissue microarray-based immunohistochemical staining showed variable CRABP-II expression patterns among 104 medulloblastoma cases, ranging from negative (42.3%), partly positive (14.4%) to positive (43.3%). CRABP-II expression was positively correlated with synaptophysin (rs = 0.317; p = 0.001) but not with CRABP-I expression ( p > 0.05). In conclusion, aberrant methylation in CRABP-II reduces the expression of CRABP-II that in turn confers RA resistance in medulloblastoma cells. Determination of CRABP-II expression or methylation status may enable a personalized RA therapy in patients with medulloblastomas and other types of cancers. (C) 2011 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.