Distinct sensitivity of neuroblastoma cells for retinoid receptor agonists: evidence for functional receptor heterodimers
Distinct sensitivity of neuroblastoma cells for retinoid receptor agonists: evidence for functional receptor heterodimers
复制标题
DOI：
10.1038/sj.onc.1201335
复制
发表时间：
1997-10-09
期刊：
影响因子：
8
通讯作者：
Chomienne, C
中科院分区：
文献类型：
--
作者：
Carpentier, A;Balitrand, N;Chomienne, C
视黄酸（RA）在神经系统的胚胎发生中起着重要作用，并已被报道在神经母细胞瘤细胞系中诱导分化。为了确定参与这种分化过程的RA信号通路，我们对两种RA敏感的神经母细胞瘤细胞系（LA-N-5和SH-SY5Y）进行了广泛研究。Northern blot实验发现，在3种RAR mrna中，只有RAR α显著表达，而RAR γ和RAR β的表达水平分别较弱或未检测到。RXRs （α和β）受体弱表达，Western blotting分析证实了RAR α的组成性表达，RAR β的缺失和RXR α的弱水平。全反式ra治疗上调RAR α并诱导RAR β急剧增加（在RNA和蛋白质水平上）。为了进一步表征RAR α、RAR β和RXR α在NB细胞中的功能，我们用EMSA法分析了LA-N-5细胞的核提取物。在RAR α、RAR β和RXR α单克隆抗体存在的情况下，观察到三个特异性延迟复合物显著减少或移位。RA治疗显著诱导dr5结合RXR α - rar β异二聚体。RAR α或RAR β激动剂与RXR α激动剂或单独使用RAR α激动剂联合治疗，诱导神经突生长，支持RXR α -RAR α或RXR α -RAR β异源二聚体参与ra介导的NB细胞分化的可能性。新的合成ra特异性受体配体的可用性应该提供组织特异性治疗方案的可能性。
Retinoic acid (RA) plays a major role in embryogenesis of the nervous system and has been reported to induce differentiation in neuroblastoma cell lines. To identify RA signaling pathways involved in such differentiation processes, two RA-sensitive neuroblastoma cell lines (LA-N-5 and SH-SY5Y) were extensively studied. Northern blot experiments determined that of the three RAR mRNAs, only RAR alpha was significantly expressed, with respectively weak or undetectable levels of RAR gamma and RAR beta. RXRs (alpha and beta) receptors were weakly expressed, Western blotting analysis confirmed the constitutive expression of RAR alpha and absence of RAR beta and weak levels of RXR alpha. Treatment with all-trans-RA up-regulated RAR alpha and induced a drastic increase of RAR beta (both at the RNA and protein level). To further characterize the function of RAR alpha, RAR beta and RXR alpha in NB cells, nuclear extracts from LA-N-5 cells were analysed by EMSA studies. Three specific retarded complexes were observed which were significantly decreased or shifted in the presence of monoclonal antibodies to RAR alpha, RAR beta and RXR alpha. RA treatment dramatically induced a DR5-binding RXR alpha-RAR beta heterodimer. Treatment with combinations of RAR alpha or RAR beta agonists with a RXR alpha agonist or with a RAR alpha agonist alone, induced neurite-outgrowth supporting the probability that both RXR alpha-RAR alpha or RXR alpha-RAR beta heterodimers are involved in RA-mediated differentiation of NB cells. The availability of novel synthetic RA-specific receptor ligands should provide the possibility of tissue specific therapeutic regimes.