Ren Y, Chan H M, Fan J, Xie Y, Chen Y X, Li W, Jiang G P, Liu Q, Meinhardt A, Tam P K H
Department of Surgery, The University of Hong Kong, Hong Kong, SAR, China.
Oncogene. 2006 Jun 15;25(25):3501-8. doi: 10.1038/sj.onc.1209395. Epub 2006 Jan 30.
Macrophage migration inhibitory factor (MIF) has been defined as a novel oncogene. Our previous results have shown that MIF may contribute to the progression of neuroblastoma by (a) inducing N-Myc expression and (b) upregulating the expression of angiogenic factors. The aim of this study was to test whether tumor growth could be inhibited by reduction of endogenous MIF expression in neuroblastoma and clarify the molecular mechanisms underlying MIF reduction on the control of neuroblastoma growth. We established human neuroblastoma cell lines stably expressing antisense MIF (AS-MIF) cDNA. These stable transfectants were characterized by cell proliferation, gene expression profile, tumorigenicity and metastasis in vitro and in vivo. Decreased MIF expression was observed after transfection with AS-MIF in neuroblastoma cells and downregulation of MIF expression significantly correlated with decreased expression of N-Myc, Ras, c-Met and TrkB at protein level. Affymetrix microarray analysis revealed that expression of IL-8 and c-met was inhibited and neuroblastoma-favorable genes such as EPHB6 and BLU were upregulated in MIF reduced cells. Neuroblastoma cell growth exhibited a nearly 80% reduction in AS-MIF transfectants in vitro. Furthermore, mice in which tumors formed after subcutaneous injection of AS-MIF transfectants showed a 90% reduction in tumor growth compared to control. Metastasis in mice was also suppressed dramatically. Our data demonstrate that targeting MIF expression is a promising therapeutic strategy in human neuroblastoma therapy, and also identifies the MIF target genes for further study.
巨噬细胞移动抑制因子（MIF）已被定义为一种新型癌基因。我们之前的研究结果表明，MIF可能通过以下方式促进神经母细胞瘤的进展：（a）诱导N-Myc表达；（b）上调血管生成因子的表达。本研究的目的是测试降低神经母细胞瘤内源性MIF表达是否能抑制肿瘤生长，并阐明MIF降低对神经母细胞瘤生长控制的分子机制。我们建立了稳定表达反义MIF（AS-MIF）cDNA的人神经母细胞瘤细胞系。通过体外和体内的细胞增殖、基因表达谱、致瘤性和转移情况对这些稳定转染子进行了表征。用AS-MIF转染神经母细胞瘤细胞后，观察到MIF表达降低，且MIF表达下调与N-Myc、Ras、c-Met和TrkB蛋白水平的表达降低显著相关。Affymetrix微阵列分析显示，在MIF降低的细胞中，IL-8和c-met的表达受到抑制，而EPHB6和BLU等对神经母细胞瘤有利的基因上调。在体外，AS-MIF转染子中的神经母细胞瘤细胞生长减少了近80%。此外，皮下注射AS-MIF转染子后形成肿瘤的小鼠，其肿瘤生长与对照组相比减少了90%。小鼠的转移也被显著抑制。我们的数据表明，靶向MIF表达是人类神经母细胞瘤治疗中一种有前景的治疗策略，同时也确定了MIF的靶基因以供进一步研究。
