Background/Objectives: Cripto-1 (CR1) is a plurifunctional embryonic protein required for implantation and re-expressed in the adult during wound repair, inflammation, and tumorigenesis. CR1 and its predicted CR1 pseudogene product Cripto-3/CR3 are highly homologous proteins, and given this physical attribute, commercially available antibodies cannot discriminate between CR1 and CR3.Methods: A series of mouse monoclonal antibodies [MoAbs] were developed with a high-affinity binding that can differentiate human CR1/CR3 proteins and showed no measurable cross-reactivity.Results: Using these reagents, we confirm that CR3 is a bona fide translated protein found in human tumor tissue, cancer cell lysates, and in normal/cancer patient donor sera. We also reveal that CR1 and CR3 compete for binding to signal transduction protein Nodal, glucose-regulated protein 78Da (GRP78), and activin receptor-like kinase 4 (Alk4). Our discriminatory MoAbs provide new reagents to help clarify current CR1/CR3 protein expression vagaries in the Cripto field of study, challenging established CR1 conventions. In addition, our data validate CR3 involvement in human carcinogenesis and cell signaling pathways, with potential clinical relevance in determining cancer patient prognosis and disease severity.
背景/目的：Cripto-1（CR1）是一种在胚胎着床过程中必需的多功能胚胎蛋白，在成年期的伤口修复、炎症反应及肿瘤发生过程中会重新表达。CR1与其预测的假基因产物Cripto-3/CR3具有高度同源性，由于这一物理特性，市售抗体无法区分CR1与CR3。 方法：本研究开发了一系列能特异性区分人源CR1/CR3蛋白的小鼠单克隆抗体，这些抗体具有高亲和力结合特性且未检测到交叉反应。 结果：利用这些特异性试剂，我们证实CR3是在人类肿瘤组织、癌细胞裂解液以及正常/癌症患者供体血清中真实存在的翻译蛋白。研究还发现CR1与CR3会竞争性结合信号转导蛋白Nodal、葡萄糖调节蛋白78kDa（GRP78）以及激活素受体样激酶4（Alk4）。本研究所开发的鉴别性单克隆抗体为澄清当前Cripto研究领域中CR1/CR3蛋白表达的模糊认知提供了新型试剂，对现有CR1研究范式提出了挑战。此外，我们的数据证实了CR3参与人类致癌过程及细胞信号通路，这对评估癌症患者预后及疾病严重程度具有潜在临床意义。
肿瘤(癌症)患者之家