R-spondins, Secreted Frizzled-Related Proteins and the Regulation of Wnt Signali

R-spondins、分泌型卷曲相关蛋白和 Wnt 信号的调节

• 批准号: 8552646
• 负责人: Jeffrey Rubin
• 金额: $ 49.81万
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8552646
• 关键词: Adult; Aftercare; Biological Assay; CXCR6 gene; Cells; Coculture Techniques; Colorectal; Conditioned Culture Media; Diagnosis; Disease; Embryonic Development; Epithelial; Epithelial Cells; Exhibits; Gene Expression; Gene Targeting; Homeostasis; Immunoblotting; Investigation; Kidney; Knowledge; Lead; Malignant Neoplasms; Mammalian Cell; Mammary gland; Mediating; Mesenchymal; Microarray Analysis; Mus; Neoplasm Metastasis; Nude Mice; Ovary; Pathway interactions; Pattern; Phenotype; Process; Property; Prostate; Recombinant Proteins; Regulation; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Stem cells; Subcutaneous Injections; Testing; Transfection; Wnt proteins; base; beta catenin; cancer type; chemokine receptor; embryo tissue; embryonic stem cell; expression vector; frizzled related protein-1; human SFRP4 protein; human embryonic stem cell; malignant breast neoplasm; matrigel; novel; research study; tumor; tumorigenic

R-spondins (Rspos) are known to potentiate Wnt/beta-catenin signaling in various settings. Activation of this pathway is critical for many processes during embryonic development and tissue homeostasis in the adult. It is one of the mechanisms that supports the proliferation of embryonic stem cells and multi-potential progenitor cells. Constitutive activation of the beta-catenin pathway is common in many types of cancers, including colorectal, hepatocellular, mammary, prostate, renal, ovary and others. Understanding the properties of factors such as the Rspos that enhance signaling through this pathway and factors like sFRP-1 that either block or potentiate Wnt signaling depending on the context could lead to better ways to diagnose and treat cancer. In addition, because Wnt signaling has many functions during embryonic development and in the adult increased knowledge of its regulation by Rspos and sFRPs could have applications in the treatment of other diseases.Microarray analysis of C57MG mouse mammary epithelial cells treated with recombinant proteins showed that Rspo2 potentiated a large percentage of Wnt-3a-dependent changes in gene expression. Many novel Wnt target genes were identified and validated by quantitative RT-PCR and immunoblotting, including CXCR6, a chemokine receptor recently implicated in breast cancer metastasis. Several changes in gene expression induced by the combination of Rspo2 and Wnt-3a did not appear to be mediated by the canonical Wnt/beta-catenin/TCF pathway, suggesting that other mechanisms were associated with Rspo activity. Double transfection of C57MG cells with Rspo2 and Wnt-1 stimulated cell invasiveness in three-dimensional Matrigel cultures as well as transwell assays. Invasive properties appeared to be independent of beta-catenin signaling. Subcutaneous injection of mammary cells transfected either with Rspo2 or Wnt-1 expression vectors produced tumors in nude mice. Co-expression of Rspo2 and Wnt-1 resulted in tumors with cells exhibiting a strong epithelial-mesenchymal transition phenotype, more pronounced than the pattern seen with the Wnt-1 transfectant.Recent experiments have shown that sFRP-1 is both a positive and negative regulator of the Wnt/beta-catenin pathway in mammalian cells. The mechanistic basis for this biphasic activity is under active investigation. A collaborative study demonstrated that the poor support afforded by certain feeder lines in co-culture with human embryonic stem cells was attributable to elevated expression and release of sFRP-1 into conditioned medium.

已知R-spondin（Rspos）在各种情况下增强Wnt/β-连环蛋白信号传导。 该途径的激活对于胚胎发育和成人组织稳态期间的许多过程至关重要。 它是支持胚胎干细胞和多潜能祖细胞增殖的机制之一。 β-连环蛋白途径的组成性激活在许多类型的癌症中是常见的，包括结肠直肠癌、肝细胞癌、乳腺癌、前列腺癌、肾癌、卵巢癌等。 了解Rspos等因子的特性可以增强通过该途径的信号传导，sFRP-1等因子可以根据环境阻断或增强Wnt信号传导，从而可以更好地诊断和治疗癌症。 此外，由于Wnt信号传导在胚胎发育过程中具有多种功能，并且在成人中增加了Rspos和sFRPs对其调节的知识，因此可以应用于其他疾病的治疗。用重组蛋白处理的C57 MG小鼠乳腺上皮细胞的微阵列分析表明，Rspo 2增强了大百分比的Wnt-3a依赖性基因表达变化。 通过定量RT-PCR和免疫印迹鉴定和验证了许多新的Wnt靶基因，包括最近与乳腺癌转移有关的趋化因子受体CXCR 6。 由Rspo 2和Wnt-3a组合诱导的基因表达的几种变化似乎不是由经典的Wnt/β-连环蛋白/TCF途径介导的，这表明其他机制与Rspo活性相关。 用Rspo 2和Wnt-1双重转染C57 MG细胞在三维Matrigel培养物以及transwell测定中刺激细胞侵袭力。 侵袭特性似乎独立于β-连环蛋白信号传导。 皮下注射用Rspo 2或Wnt-1表达载体转染的乳腺细胞在裸鼠中产生肿瘤。 Rspo 2和Wnt-1的共表达导致肿瘤细胞表现出强烈的上皮-间充质转化表型，比Wnt-1转染子所见的模式更明显。 这种双相活性的机制基础正在积极研究中。 一项合作研究表明，与人胚胎干细胞共培养的某些饲养细胞系提供的支持较差，这归因于sFRP-1的表达升高和释放到条件培养基中。