Regulation of sonic hedgehog-GLI1 downstream target genes PTCH1, Cyclin D2, Plakoglobin, PAX6 and NKX2.2 and their epigenetic status in medulloblastoma and astrocytoma

BMC Cancer

Research Article

Javier S Castresana¹  Mehdi H Shahi²  Subrata Sinha³  Xing Fan⁴  Charles G Eberhart⁵  Mohammad Afzal⁶  Juan A Rey⁷ 

[1] Brain Tumor Biology Unit-CIFA, University of Navarra School of Sciences, Pamplona, Spain;Brain Tumor Biology Unit-CIFA, University of Navarra School of Sciences, Pamplona, Spain;Department of Zoology, Aligarh Muslim University, Aligarh, India;Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, India;Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, India;Department of Neurosurgery, University of Michigan Medical School, Ann Arbor, MI, USA;Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA;Department of Zoology, Aligarh Muslim University, Aligarh, India;Research Unit, La Paz University Hospital, Madrid, Spain;

关键词: Medulloblastoma;    GLI1 Expression;    Daoy Cell;    Astrocytoma Cell Line;    Medulloblastoma Cell Line;   

DOI  :  10.1186/1471-2407-10-614

 received in 2009-03-26, accepted in 2010-11-08,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundThe Sonic hedgehog (Shh) signaling pathway is critical for cell growth and differentiation. Impairment of this pathway can result in both birth defects and cancer. Despite its importance in cancer development, the Shh pathway has not been thoroughly investigated in tumorigenesis of brain tumors. In this study, we sought to understand the regulatory roles of GLI1, the immediate downstream activator of the Shh signaling pathway on its downstream target genes PTCH1, Cyclin D2, Plakoglobin, NKX2.2 and PAX6 in medulloblastoma and astrocytic tumors.MethodsWe silenced GLI1 expression in medulloblastoma and astrocytic cell lines by transfection of siRNA against GLI1. Subsequently, we performed RT-PCR and quantitative real time RT-PCR (qRT-PCR) to assay the expression of downstream target genes PTCH1, Cyclin D2, Plakoglobin, NKX2.2 and PAX6. We also attempted to correlate the pattern of expression of GLI1 and its regulated genes in 14 cell lines and 41 primary medulloblastoma and astrocytoma tumor samples. We also assessed the methylation status of the Cyclin D2 and PTCH1 promoters in these 14 cell lines and 58 primary tumor samples.ResultsSilencing expression of GLI1 resulted up-regulation of all target genes in the medulloblastoma cell line, while only PTCH1 was up-regulated in astrocytoma. We also observed methylation of the cyclin D2 promoter in a significant number of astrocytoma cell lines (63%) and primary astrocytoma tumor samples (32%), but not at all in any medulloblastoma samples. PTCH1 promoter methylation was less frequently observed than Cyclin D2 promoter methylation in astrocytomas, and not at all in medulloblastomas.ConclusionsOur results demonstrate different regulatory mechanisms of Shh-GLI1 signaling. These differences vary according to the downstream target gene affected, the origin of the tissue, as well as epigenetic regulation of some of these genes.

【 授权许可】

Unknown   
© Shahi et al; licensee BioMed Central Ltd. 2010. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.