DKK-1在神经母细胞瘤分化调控中的作用及其分子机制研究

As one of the most common malignant solid tumors in children with high malignancy and poor prognosis, neuroblastoma (NB) has unique biological characteristics of spontaneous regression and induced differentiation in vitro. Our previous study confirmed that, aberrant activation of Wnt signaling pathway is involved in the regulation of NB malignant behaviors. DKK-1 (Dickkopf-1) has been confirmed as an important suppressor gene of Wnt signaling pathway in recent years. The current studies show that, the functions of DKK-l in adult tumors remain controversial with complex expressions and biological functions. The expression and function of DKK-1 in NB have not been elucidated. Therefore, further studies by using more respects and effective research techniques are urgent for the expression, function and mechanism of DKK-1 in NB. In pre-experiment, we found that DKK-1 was frequently downregulated in human NB tissues and cell lines. Further, we prepare to investigate the role of DKK-1 in the regulation of NB differentiation by using lentiviral vector expressing DKK-1 and explore the status of DKK-1 promoter methylation in vivo and vitro experiments. Finally, we seek to study the regulation of DKK-1 in Wnt/β-catenin signaling pathway. In this study, we aim to clarify the function and molecular mechanism of DKK-1 in regulating NB differentiation, and the epigenetic mechanism of the abnormal expression of DKK-1 in NB. This study may provide a new theoretical basis for revealing the mechanism of NB occurrence and development, and introduce new ideas and possible molecular target for NB treatment.

神经母细胞瘤（neuroblastoma, NB）恶性程度高，预后差，是小儿最常见的恶性实体肿瘤之一，具有自行消退和体外诱导分化的独特生物学特性。我们前期研究证实：NB中存在异常活化的Wnt通路，且Wnt通路参与调控NB细胞的恶性生物学行为。DKK-1 (Dickkopf-1)是近年确认的Wnt通路重要抑制基因。目前，DKK-1在成人肿瘤中的表达及功能存有争议，而DKK-1在NB中的表达及功能尚未明确阐述。课题组前期预实验发现，DKK-1在人NB组织及细胞株中均呈低表达。因此，我们以NB的分化调控为切入点，通过构建DKK-1慢病毒过表达载体，采用细胞及动物实验，对DKK-1在NB分化调控中的作用及其启动子甲基化进行探索，并研究DKK-1对Wnt通路活性及通路中游关键基因、下游重要靶基因表达的影响。本课题旨在阐明DKK-1在NB分化调控中的作用及其分子机制，并探讨其异常表达的表观遗传学机制。

神经母细胞瘤（neuroblastoma, NB）恶性程度高，预后差，是小儿最常见的恶性实体肿瘤之一，具有自行消退和体外诱导分化的独特生物学特性。我们前期研究证实：NB中存在异常活化的Wnt通路，且Wnt通路参与调控NB细胞的恶性生物学行为。DKK-1 (Dickkopf-1)是近年确认的Wnt通路重要抑制基因。目前，DKK-1在成人肿瘤中的表达及功能存有争议，而DKK-1在NB中的表达及功能尚未明确阐述。我们通过本研究发现DKK-1在NB中处于启动子高甲基化状态的低表达水平。DKK-1的表达可以显著调控NB细胞的分化。作为一种抑癌基因，DKK-1不仅能够抑制Wnt信号通路的活性，而且可以通过Wnt信号通路的调节参与调控NB细胞的生物学活性。这为阐述DKK-1在NB中作用的相关分子机制奠定了重要的理论基础。另外，作为一个特殊标记物和分子靶点，DKK-1有望成为NB早期诊断的潜在指标及抗癌治疗中新的靶点。