Martin Darryl T, Gendron Robert L, Jarzembowski Jason A, Perry Arie, Collins Margaret H, Pushpanathan Chitra, Miskiewicz Ewa, Castle Valerie P, Paradis Hélène
Department of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada.
Clin Cancer Res. 2007 Mar 1;13(5):1480-7. doi: 10.1158/1078-0432.CCR-06-1716.
The discovery and validation of new prognostic factors and further refinement of risk group stratification are needed to improve clinical interpretation of neuroblastoma. Our laboratory isolated and characterized a developmentally regulated gene named TUBEDOWN against which we have raised a monoclonal antibody (OE5). Tubedown becomes down-regulated postnatally yet remains strongly expressed in some neuroblastomas. The purpose of this study is to define the utility of Tubedown expression as a new measure of the differentiation status and aggressiveness of neuroblastic tumors.
Tubedown protein expression was quantitatively assessed in neuroblastic tumors (neuroblastomas, ganglioneuroblastomas, and ganglioneuromas) and normal adrenal tissues using Western blot and OE5 immunohistochemistry. Regulation of Tubedown expression during retinoic acid-induced neuronal differentiation in neuroblastoma cell lines was assessed by Western blotting.
High levels of Tubedown expression are observed in tumors with significant neuroblastic component, unfavorable histopathology, advanced stage, high-risk group, and poor outcome. In contrast, more differentiated subsets of neuroblastic tumors, ganglioneuroblastomas with favorable histopathology and ganglioneuromas, express low levels of Tubedown. In vitro, marked retinoic acid-induced neuronal differentiation responses of neuroblastoma cells are associated with a significant decrease in Tubedown expression, whereas limited neuronal differentiation responses to retinoic acid were associated with little or no decrease in Tubedown expression.
Our results indicate that the levels of Tubedown expression are linked to the differentiation status and aggressiveness of neuroblastic tumors and represent an independent prognostic factor for neuroblastoma. Tubedown expression may be useful to more accurately define different neuroblastic tumor subsets and ultimately provide more adequate assessment and treatment for neuroblastoma patients.
为了改善神经母细胞瘤的临床诊断，需要发现并验证新的预后因素，进一步完善风险组分层。我们的实验室分离并鉴定了一个受发育调控的基因，命名为Tubedown，并针对该基因制备了单克隆抗体（OE5）。Tubedown在出生后表达下调，但在一些神经母细胞瘤中仍强烈表达。本研究的目的是确定Tubedown表达作为神经母细胞瘤分化状态和侵袭性新指标的效用。
使用蛋白质免疫印迹法和OE5免疫组织化学方法，对神经母细胞瘤、神经节神经母细胞瘤、神经节神经瘤和正常肾上腺组织中的Tubedown蛋白表达进行定量评估。通过蛋白质免疫印迹法评估维甲酸诱导神经母细胞瘤细胞系神经元分化过程中Tubedown表达的调控情况。
在具有显著神经母细胞成分、组织病理学不良、晚期、高危组和预后不良的肿瘤中观察到高水平的Tubedown表达。相反，神经母细胞瘤更具分化性的亚组、组织病理学良好的神经节神经母细胞瘤和神经节神经瘤表达低水平的Tubedown。在体外，维甲酸诱导的神经母细胞瘤细胞显著的神经元分化反应与Tubedown表达的显著降低相关，而对维甲酸有限的神经元分化反应与Tubedown表达很少或没有降低相关。
我们的结果表明，Tubedown表达水平与神经母细胞瘤的分化状态和侵袭性相关，是神经母细胞瘤的一个独立预后因素。Tubedown表达可能有助于更准确地定义不同的神经母细胞瘤亚组，并最终为神经母细胞瘤患者提供更充分的评估和治疗。
