Wnt antagonist genes in kidney tumor progression and metastasis

描述（由申请人提供）：肾脏肿瘤进展和转移中的Wnt拮抗剂基因。本课题的主要目的是研究Wnt拮抗基因在肾癌发生发展和转移中的作用。基本原理是Wnt拮抗剂基因通过CpG甲基化途径失活，结果Wnt/β-连环蛋白途径被激活并诱导各种器官的恶性转化。然而，这种研究缺乏肾癌。将测试三个特定假设以确定：1）Wnt拮抗剂基因的失活是否涉及肾癌的进展和转移。2)Wnt拮抗剂基因的失活机制是通过表观遗传途径，如DNA甲基化、组蛋白修饰和染色质重塑。3)转染Wnt拮抗基因抑制肾癌的生长和转移为了验证这些假设，我们将追求以下具体目标。具体目标1：探讨Wnt拮抗剂基因失活是否参与人肾癌的发生发展和转移。基于初步的数据，我们筛选了几个Wnt拮抗剂基因，并确定了6个基因在肾癌中沉默。这些基因是：分泌型卷曲相关蛋白-1（sFRP-1）、sFRP-2、sFRP-4、sFRP-5、Wnt抑制因子-1（Wif-1）和DICKKOPF-3（DKK-3）。在此特定目标下，我们将确定Wnt拮抗剂基因在正常和不同阶段和级别的肾癌中的mRNA和蛋白表达水平。通过实时RT-PCR分析mRNA表达，通过免疫组织化学和Western印迹分析蛋白质表达。具体目标#2：研究肾癌中Wnt拮抗剂基因失活的机制。在此目标下，我们将使用亚硫酸氢钠甲基化技术分析Wnt拮抗剂基因启动子区域中CpG岛的超甲基化，并通过直接DNA测序进行确认。我们还将通过分析肾癌组织中的这些参数来研究Wnt拮抗剂基因失活的机制是否是由于DNA甲基转移酶（DNMT-1、DNMT 3a、DNMT 3b）、去甲基化酶（MBD 2）基因、组蛋白乙酰化和染色质重塑。具体目标#3：研究Wnt拮抗剂基因在肾癌中的功能作用。在此目标下，我们将在显性阴性肾癌细胞中克隆全长Wnt拮抗剂基因cDNA，建立稳定的转染细胞。我们将分析转染的肾癌细胞的体外和体内生长。还分析转染细胞和亲本细胞的体外侵袭性（细胞外基质结合试验、侵袭试验和软琼脂集落形成效率）。这些实验的成功完成将证明Wnt拮抗剂基因在抑制肾癌生长、进展和转移中的功能作用以及这些基因在肾癌中失活的机制。在未来，这些结果可能为肾癌进展和转移的管理提供更好的策略。肾细胞癌（RCC）是泌尿生殖系统的第三大常见恶性肿瘤。基于已发表的文献，很明显Wnt拮抗剂基因与各种癌症相关。然而，这种研究缺乏肾癌。我们已经提出了研究Wnt拮抗剂基因在肾细胞癌的进展和转移中的功能作用，使用体外和体内模型。成功完成拟议的实验可能会为我们提供更好的策略，为肾癌的管理。

DESCRIPTION (provided by applicant): Wnt antagonist genes in kidney tumor progression and metastasis. Main goal of this project is to investigate the role of Wnt antagonist genes in the progression and metastasis of renal cancer. The rationale is that Wnt antagonist genes are inactivated through CpG methylation pathways with the result that Wnt/ b-catenin pathways are activated and induce malignant transformation of various organs. However, such studies are lacking in kidney cancer. Three specific hypotheses will be tested to determine if: 1) Inactivation of Wnt antagonist genes is involved in the progression and metastasis of kidney cancer. 2) The mechanisms of inactivation of the Wnt antagonist genes are through epigenetic pathways such as DNA methylation, histone modification and chromatin remodeling. 3) Transfection of Wnt antagonist genes suppresses the in vitro and in vivo growth and metastasis of kidney cancer. To test these hypotheses, we will pursue the following specific aims. Specific Aim # 1: To investigate whether inactivation of Wnt antagonist genes is involved in the progression and metastasis of human renal cell carcinoma. Based on the preliminary data, we have screened several Wnt antagonist genes and have identified six genes that are silenced in kidney cancer. These genes are: secreted frizzled-related protein-1 (sFRP-1), sFRP-2, sFRP-4, sFRP-5, Wnt inhibitory factor-1 (Wif-1) and DICKKOPF-3 (DKK-3). Under this specific aim, we will determine the levels of mRNA and protein expression of Wnt antagonist genes in normal and different stages and grades of kidney cancer. The mRNA expression will be analyzed by real-time RT- PCR and protein expression by immunohistochemistry and Western blotting. Specific Aim # 2: To investigate the mechanisms of inactivation of Wnt antagonist genes in kidney cancer. Under this aim, we will analyze hypermethylation of CpG Islands in promoter regions of Wnt antagonist genes using sodium bisulfite methylation techniques and confirm by direct DNA sequencing. We will also investigate whether the mechanisms of inactivation of Wnt antagonist genes are due to DNA methyltransferase (DNMT-1, DNMT3a, DNMT3b), demethylase (MBD2) genes, histone acetylation and chromatin remodeling through analysis of these parameters in kidney cancer tissues. Specific Aim # 3: To investigate the functional role of Wnt antagonist genes in kidney cancer. Under this specific aim, we will transfect full-length Wnt antagonist gene cDNA in dominant-negative kidney cancer cells and establish the stable transfectant cells. We will analyze in vitro and in vivo growth of transfected kidney cancer cells. Also analyze in vitro invasiveness (extra-cellular matrix binding assay, invasion assay and soft agar colony forming efficiency) of transfected and parental cells. Successful completion of these experiments will demonstrate the functional role of Wnt antagonist genes in the suppression of kidney cancer growth, progression and metastasis and also the mechanism of inactivation of these genes in kidney cancer. In the future, these results may provide better strategies for the management of kidney cancer progression and metastasis. Renal cell carcinoma (RCC) is the third most common malignancy of the genitourinary system. Based on the published literature, it is clear that Wnt antagonist genes are associated with various cancers. However, such studies are lacking in kidney cancer. We have proposed to investigate the functional role of Wnt antagonist genes in the progression and metastasis of renal cell carcinoma using both in vitro and in vivo models. Successful completion of proposed experiments may provide us with the better strategies for the management of kidney cancer.