Cripto Antagonism of Activin and TGF-Beta Signalling

激活素和 TGF-β 信号传导的 Cripto 拮抗作用

• 批准号: 6769849
• 负责人: WYLIE W. VALE
• 金额: $ 30.54万
• 依托单位: SALK INSTITUTE FOR BIOLOGICAL STUDIES
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-06-01 至 2009-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6769849
• 关键词: MCF7 cell; activins; biological signal transduction; breast neoplasms; cell proliferation; growth factor receptors; hormone inhibitor; laboratory rabbit; molecular oncology; neutralizing antibody; oncoproteins; phosphorylation; protein binding; protein structure function; transcription factor; transforming growth factors; MCF7 cell; activins; biological signal transduction; breast neoplasms; cell proliferation; growth factor receptors; hormone inhibitor; laboratory rabbit; molecular oncology; neutralizing antibody; oncoproteins; phosphorylation; protein binding; protein structure function; transcription factor; transforming growth factors

DESCRIPTION (provided by applicant): TGF-B and activin are functionally related members of the TGF-Beta superfamily of growth and differentiation factors. TGF-Beta and activin activate Smad2 and Smad3 and they both regulate tissue homeostasis by potently inhibiting proliferation of multiple cell types, including epithelial cells. Disruption of the antiproliferative response to activin and/or TGF-Beta is associated with dysregulated cellular proliferation, oncogenesis and progression toward the malignant phenotype. Cripto is a developmental oncoprotein that is overexpressed in multiple human tumors including approximately 80% of human breast tumors. Cripto overexpression transforms mammary epithelial ceils and activates the growth promoting Erk/MAPK and PI3K signaling pathways. Cripto and related EGF-CFC proteins also play essential signaling roles during embryonic development and Cripto is required for mesoderm induction and cardiogenesis. It has been shown that Cripto acts as a coreceptor to facilitate receptor assembly and signaling via activin type II/I receptors by the TGF-Beta superfamily members nodal, Vgl and GDF1. This led us to test whether Cripto may regulate the ability of activin and possibly other TGF-Beta ligands to assemble functional receptor complexes and we showed that Cripto binds activin in the presence of type II activin receptors, competes with ALK4 for binding to activin and antagonizes activin signaling. We now have evidence showing that Cripto also binds TGF-Beta in the presence of TBRII, competes with ALK5 for TGF-Beta binding and antagonizes TGF-Beta signaling; we propose, therefore, that Cripto may be generally capable of blocking antiproliferative Smad2/3 signals. Under Aim I of this proposal we will identify the molecular determinants on Cripto that mediate Cripto binding to activin/TFG-Beta and antagonism of activin/TGF-Beta signaling. We also propose to develop reagents including anti-Cripto neutralizing antibodies designed to prevent the ability of Cripto to antagonize activin and TGF-Beta signaling. Aim II proposes to characterize the ability of Cripto to block type I receptor recruitment to ligand-type II receptor complexes and block type I receptor phosphorylation in breast cancer cells in vitro in response to activin/TGF-Beta and the ability of Cripto to block phosphorylation of Smad2/3 following activin/TGF-beta treatment of breast cancer cells in vitro. Under Aim III we will characterize the effects of Cripto on activin/TGF-Beta-induced growth inhibition in three mammary epithelial-derived cell lines: MCF-7; MCF-10A; and CID-9 cells. Together, these studies will lead to an improved understanding of the mechanisms of Cripto action and will help illuminate therapeutic targets for the management of neoplastic disease.

描述（由申请人提供）：TGF-B和激活素是生长和分化因子的TGF-BETA超家族的功能相关的成员。 TGF-β和激活素激活SMAD2和SMAD3，它们都通过有效抑制包括上皮细胞在内的多种细胞类型的增殖来调节组织稳态。对激活素和/或TGF-β的抗增殖反应的破坏与细胞增殖，肿瘤发生和向恶性表型的进展有关。 Cripto是一种发育性癌蛋白，在包括大约80％的人类乳腺肿瘤在内的多种人类肿瘤中过表达。 Cripto过表达会改变乳腺上皮天花板，并激活促进ERK/MAPK和PI3K信号通路的生长。 Cripto和相关的EGF-CFC蛋白在胚胎发育过程中还起着必不可少的信号传导作用，并且需要进行中胚层诱导和心脏病。已经表明，Cripto充当了TGF-BETA超家族成员Nodal，VGL和GDF1通过AIVICIN II/I受体促进受体组装和信号传导的共感染者。这导致我们测试Cripto是否可以调节激活素和其他TGF-β配体组装功能受体复合物的能力，我们表明Cripto在存在II型激活蛋白受体的存在下结合了激活素，与ALK4竞争ALK4竞争与激活素结合并拮抗激活素信号。我们现在有证据表明，在存在TBRII的情况下，Cripto还结合TGF-beta，与ALK5竞争TGF-β结合并拮抗TGF-beta信号传导。因此，我们提出，Cripto通常能够阻止抗增殖性SMAD2/3信号。在该建议的目标下，我们将确定Cripto上的分子决定因素，该分子介导了cripto与激活素/TFG-β的结合以及激活素/TGF-β信号传导的拮抗作用。我们还建议开发试剂，包括抗本术中和抗体，旨在防止Cripto拮抗激活素和TGF-β信号传导的能力。 AIM II提议表征Cripto阻止I型受体募集到配体型II受体复合物和I型受体受体磷酸化的乳腺癌细胞中的I型受体磷酸化的能力，以响应激活蛋白/TGF-BETA，以及Cripto在激活蛋白/TGF-BETA治疗后，Cripto阻断SMAD2/3的磷酸化的能力。在AIM III下，我们将表征Cripto对三种乳腺上皮衍生细胞系中激活素/TGF-Beta诱导的生长抑制的影响：MCF-7； MCF-10A;和CID-9细胞。总之，这些研究将导致对Cripto作用机制的了解，并有助于阐明治疗靶标以治疗肿瘤疾病。