Yamanaka Hiroaki, Oue Takaharu, Uehara Shuichiro, Fukuzawa Masahiro
Department of Surgery, Division of Pediatric Surgery, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
Mol Med Rep. 2010 Jan-Feb;3(1):133-9. doi: 10.3892/mmr_00000230.
The Hedgehog (Hh) signaling pathway regulates the development of many organs in mammals. Recent studies have indicated that the activation of the Hh signaling pathway contributes to the growth of various adult cancers. However, little is known about its role in the development of pediatric malignancies. The present study was undertaken to examine the expression and functional involvement of Hh signal transcription factors in pediatric tumor cells in order to determine their potential as therapeutic targets. We utilized real-time RT-PCR to investigate the expression of Glioma-associated oncogene homolog 1 (Gli1) in various pediatric tumor cell lines, including rhabdomyosarcoma, neuroblastoma and hepatoblastoma. The mRNA expression of Gli1 was markedly increased in rhabdomyosarcoma (RMS-YM, RD, RH30) cell lines, and moderately increased in neuroblastoma (NB19) and hepatoblastoma (Huh6) cell lines. The proliferation of these cell lines was dose dependently inhibited by Forskolin, a specific Hh signal inhibitor. In addition, Forskolin-induced growth suppression was associated with the down-regulation of C-Myc. Moreover, the blockade of Hh signaling with Forskolin enhanced cell apoptosis in a dose-dependent manner. These results demonstrated that Hh signal activation frequently occurs in neuroblastoma, hepatoblastoma and rhabdomyosarcoma cell lines. The inhibition of Hh signaling suppressed proliferation and increased apoptosis in these tumor cells. These findings suggest that the Hh signaling pathway plays an important role in tumorigenesis and is a potential molecular target of new treatment strategies for these pediatric malignant tumors.
刺猬信号通路（Hh）调节哺乳动物许多器官的发育。最近的研究表明，Hh信号通路的激活促进了各种成人癌症的生长。然而，关于其在儿童恶性肿瘤发生中的作用却知之甚少。本研究旨在检测Hh信号转录因子在儿童肿瘤细胞中的表达及功能参与情况，以确定它们作为治疗靶点的潜力。我们利用实时逆转录聚合酶链反应（RT-PCR）研究了胶质瘤相关癌基因同源物1（Gli1）在各种儿童肿瘤细胞系中的表达，这些细胞系包括横纹肌肉瘤、神经母细胞瘤和肝母细胞瘤。Gli1的信使核糖核酸（mRNA）表达在横纹肌肉瘤（RMS-YM、RD、RH30）细胞系中显著增加，在神经母细胞瘤（NB19）和肝母细胞瘤（Huh6）细胞系中适度增加。这些细胞系的增殖受到特异性Hh信号抑制剂福司可林的剂量依赖性抑制。此外，福司可林诱导的生长抑制与C-Myc的下调有关。而且，用福司可林阻断Hh信号以剂量依赖性方式增强细胞凋亡。这些结果表明，Hh信号激活在神经母细胞瘤、肝母细胞瘤和横纹肌肉瘤细胞系中经常发生。抑制Hh信号可抑制这些肿瘤细胞的增殖并增加凋亡。这些发现提示，Hh信号通路在肿瘤发生中起重要作用，并且是这些儿童恶性肿瘤新治疗策略的潜在分子靶点。
