Ghosh Susmita, Ghosh Amlan, Maiti Guru Prasad, Alam Neyaz, Roy Anup, Roychoudhury Susanta, Panda Chinmay Kumar
Department of Oncogene Regulation, Chittaranjan National Cancer Institute, 37, S.P. Mukherjee Road, Kolkata, 700026, India.
Hum Genet. 2009 Mar;125(2):189-98. doi: 10.1007/s00439-008-0610-9. Epub 2008 Dec 24.
Deletion of chromosomal 3p12.3 was suggested to be associated with dysplastic lesions of head and neck. This region harbors two candidate tumor suppressors ROBO1/DUTT1, ROBO2 and two non-coding RNAs (ncRNAs) located at intron 2 of ROBO1/DUTT1. Aim of this study is to understand the role of these genes in development of head and neck squamous cell carcinoma. A collection of 72 dysplastic lesions and 116 HNSCC samples and two oral cancer cell lines were analyzed for ROBO1/DUTT1 and ROBO2 deletion and promoter methylation. ROBO1/DUTT1, ROBO2 and two ncRNAs mRNA expression were analyzed by Q-PCR. Immunohistochemical analysis of ROBO1/DUTT1 and ROBO2 was performed. Alterations of these genes were correlated with different clinicopathological parameters. High frequency of molecular alterations (deletion/methylation) was seen in ROBO1/DUTT1 than ROBO2. In mild dysplastic lesions both of these genes showed high molecular alterations and remained more or less constant in subsequent stages. Q-PCR analysis showed reduced expression of these genes and the two ncRNAs. In vitro demethylation experiment by 5-aza-dC showed upregulation of ROBO1/DUTT1 and ROBO2 while the expression of the ncRNAs remained unchanged. Immunohistochemical analysis of ROBO1/DUTT1 and ROBO2 showed concordance with their mRNA expression and molecular alterations. Poor patients' outcome was predicted in the cases with alteration of ROBO1/DUTT1 along with tobacco addiction and nodal involvement. Our data suggests (a) ROBO1/DUTT1 and the ncRNAs are transcribed from different promoters, and (b) inactivation of ROBO1/DUTT1 could be used as molecular signature for early detection and prognosis of the head and neck cancer.
染色体3p12.3的缺失被认为与头颈部发育异常病变有关。该区域包含两个候选肿瘤抑制基因ROBO1/DUTT1、ROBO2以及位于ROBO1/DUTT1第2内含子的两个非编码RNA（ncRNA）。本研究的目的是了解这些基因在头颈部鳞状细胞癌发生发展中的作用。对72例发育异常病变、116例头颈部鳞状细胞癌样本以及两种口腔癌细胞系进行分析，检测ROBO1/DUTT1和ROBO2的缺失及启动子甲基化情况。通过定量聚合酶链反应（Q-PCR）分析ROBO1/DUTT1、ROBO2和两个ncRNA的mRNA表达。对ROBO1/DUTT1和ROBO2进行免疫组织化学分析。将这些基因的改变与不同的临床病理参数相关联。ROBO1/DUTT1的分子改变（缺失/甲基化）频率高于ROBO2。在轻度发育异常病变中，这两个基因均显示出较高的分子改变，且在后续阶段或多或少保持恒定。Q-PCR分析显示这些基因和两个ncRNA的表达降低。5-氮杂-2'-脱氧胞苷（5-aza-dC）体外去甲基化实验显示ROBO1/DUTT1和ROBO2表达上调，而ncRNA的表达保持不变。ROBO1/DUTT1和ROBO2的免疫组织化学分析结果与其mRNA表达及分子改变一致。在伴有ROBO1/DUTT1改变且有烟草成瘾和淋巴结受累的病例中，预测患者预后较差。我们的数据表明：（a）ROBO1/DUTT1和ncRNA由不同启动子转录；（b）ROBO1/DUTT1的失活可作为头颈部癌症早期检测和预后的分子标志物。
