Revet Ingrid, Huizenga Gerda, Chan Alvin, Koster Jan, Volckmann Richard, van Sluis Peter, Øra Ingrid, Versteeg Rogier, Geerts Dirk
Department of Human Genetics, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
Exp Cell Res. 2008 Feb 15;314(4):707-19. doi: 10.1016/j.yexcr.2007.12.008. Epub 2008 Jan 16.
Neuroblastoma is an embryonal tumour of the peripheral sympathetic nervous system (SNS). One of the master regulator genes for peripheral SNS differentiation, the homeobox transcription factor PHOX2B, is mutated in familiar and sporadic neuroblastomas. Here we report that inducible expression of PHOX2B in the neuroblastoma cell line SJNB-8 down-regulates MSX1, a homeobox gene important for embryonic neural crest development. Inducible expression of MSX1 in SJNB-8 caused inhibition of both cell proliferation and colony formation in soft agar. Affymetrix micro-array and Northern blot analysis demonstrated that MSX1 strongly up-regulated the Delta-Notch pathway genes DLK1, NOTCH3, and HEY1. In addition, the proneural gene NEUROD1 was down-regulated. Western blot analysis showed that MSX1 induction caused cleavage of the NOTCH3 protein to its activated form, further confirming activation of the Delta-Notch pathway. These experiments describe for the first time regulation of the Delta-Notch pathway by MSX1, and connect these genes to the PHOX2B oncogene, indicative of a role in neuroblastoma biology. Affymetrix micro-array analysis of a neuroblastic tumour series consisting of neuroblastomas and the more benign ganglioneuromas showed that MSX1, NOTCH3 and HEY1 are more highly expressed in ganglioneuromas. This suggests a block in differentiation of these tumours at distinct developmental stages or lineages.
神经母细胞瘤是一种起源于外周交感神经系统（SNS）的胚胎性肿瘤。外周SNS分化的主要调控基因之一，即同源盒转录因子PHOX2B，在家族性和散发性神经母细胞瘤中发生突变。在此，我们报告在神经母细胞瘤细胞系SJNB - 8中诱导性表达PHOX2B可下调MSX1，MSX1是一种对胚胎神经嵴发育很重要的同源盒基因。在SJNB - 8中诱导性表达MSX1可抑制细胞增殖以及软琼脂中的集落形成。基因芯片分析和Northern印迹分析表明，MSX1强烈上调Delta - Notch信号通路基因DLK1、NOTCH3和HEY1。此外，神经源性基因NEUROD1被下调。蛋白质印迹分析表明，MSX1的诱导导致NOTCH3蛋白切割成其活化形式，进一步证实了Delta - Notch信号通路的激活。这些实验首次描述了MSX1对Delta - Notch信号通路的调控，并将这些基因与PHOX2B癌基因联系起来，提示其在神经母细胞瘤生物学中的作用。对由神经母细胞瘤和更良性的神经节神经瘤组成的神经母细胞瘤系列进行基因芯片分析表明，MSX1、NOTCH3和HEY1在神经节神经瘤中表达更高。这表明这些肿瘤在不同发育阶段或谱系的分化受阻。
