Mechanisms and therapeutic targeting of colon cancer stem cell plasticity

结肠癌干细胞可塑性的机制和治疗靶点

• 批准号: 9896787
• 负责人: Kendra S. Carmon
• 金额: $ 35.23万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-04-01 至 2023-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9896787
• 关键词: ADGR1 gene; Ablation; Address; Adhesions; Affect; Affinity; Aftercare; Antibodies; Antibody-drug conjugates; Automobile Driving; Binding; Biological; Bispecific Antibodies; Cell Adhesion; Cell surface; Cell-Cell Adhesion; Cells; Cessation of life; Characteristics; Colon; Colon Carcinoma; Colonic Neoplasms; Data; Development; Disease; Drug resistance; EGF gene; Epiregulin; Epithelial; Epithelium; G-Protein-Coupled Receptors; Genetic; Goals; Growth; Growth Factor; IQ motif containing GTPase activating protein 1; Intestines; Knock-out; LGR5 gene; Label; Leucine-Rich Repeat; Ligands; Maintenance; Malignant Neoplasms; Mediating; Microarray Analysis; Modeling; Mucous Membrane; Natural regeneration; Neoplasm Metastasis; Normal tissue morphology; Organoids; Pathway interactions; Patients; Pharmaceutical Preparations; Phenotype; Play; Proliferating; Property; Protein Array Analysis; Recovery; Recurrent disease; Regulation; Relapse; Reporting; Research; Resistance; Rhodopsin; Role; STAT3 gene; Scaffolding Protein; Signal Pathway; Signal Transduction; Solid Neoplasm; Testing; Therapeutic; Tissues; Toxin; Tumor Tissue; Work; Xenograft Model; Xenograft procedure; adult stem cell; antibody conjugate; base; beta catenin; cancer cell; cancer drug resistance; cancer stem cell; cancer therapy; cell motility; chemotherapy; colon cancer cell line; colon cancer treatment; daughter cell; drug sensitivity; effective therapy; fitness; genome-wide; in vivo; innovation; insight; knock-down; member; novel; protein activation; receptor; safety testing; self-renewal; stem cell therapy; stem cells; stem-like cell; stemness; targeted treatment; theories; therapeutic target; therapy development; tool; transcriptome; transcriptome sequencing; tumor; tumor growth; tumor xenograft; tumorigenesis

ABSTRACT: Tumor-initiating or cancer stem cells (CSCs) have been implicated in drug resistance, metastasis, and relapse, making CSCs a major impediment for the effective treatment of cancer. Recent studies have unequivocally established that the adult stem cell marker LGR5 (leucine-rich repeat-containing, G protein-coupled receptor 5) is highly expressed in primary colon tumors and only LGR5-positive colon CSCs are capable of driving tumor growth and metastasis. However, the function and mechanism of LGR5 in CSCs is still relatively unknown. We generated LGR5-targeted antibody-drug conjugates (ADCs) incorporating the toxin monomethyl-auristatin E and showed they could destroy colon cancer cells and xenografts, yet tumors eventually recurred. Furthermore, selective genetic ablation of LGR5-positive colon CSCs failed to completely eradicate tumors since LGR5-negative cancer cells were able to rapidly regenerate LGR5-positive cells after treatment was terminated, indicating a high degree of cancer cell plasticity. Therefore, to develop therapies that completely eradicate primary colon tumors and metastatic disease, it is critical to identify LGR5-mediated functions and signaling pathways involved in CSC plasticity. We reported that LGR5 binds R-spondin growth factors and functions to potentiate Wnt/beta-catenin signaling, an essential pathway that is activated in CSCs. Recently, we have found that LGR5 interacts with the scaffold protein IQGAP1 (IQ Motif Containing GTPase Activating Protein 1) to increase cell-cell adhesion in colon cancer cells and knockdown of LGR5 significantly enhanced drug resistance and activation of proteins associated with survival signaling. Loss of LGR5 induced expression of adhesion G-protein-coupled receptor GPR56, which is highly upregulated in colon tumors. In Aim 1, we will determine the roles and mechanisms of LGR5 in the control of stemness and drug resistance of CSCs. We will investigate how LGR5 knockout (KO) compared to elimination of LGR5-positive CSCs affects tumor growth, metastasis, drug resistance, and cancer cell signaling using patient-derived xenograft (PDX) organoids models ex vivo and in vivo. The role of LGR5-IQGAP1 interaction in regulating the different properties that define CSCs will also be examined. In Aim 2, we will develop unique bispecific ADCs to target CSC plasticity. We will test safety, efficacy and establish proof-of-concept for dual-targeted therapeutics to simultaneously destroy both LGR5-positive CSCs and LGR5-negative cancer cells. In Aim 3, we will characterize and validate GPR56 as a novel target for colon cancer by delineating its roles in tumor growth and drug resistance using GPR56 KO colon cancer cell lines and PDX models. This study will uncover the function and mechanism of LGR5 in CSCs and generate innovative therapeutic leads to target stemness and plasticity for the treatment and eradication of colon cancer.

抽象的： 肿瘤引起或癌症干细胞（CSC）已与耐药性，转移和复发有关， 使CSC成为有效治疗癌症的主要障碍。最近的研究明确 确定成年干细胞标记LGR5（富含亮氨酸的重复，G蛋白偶联受体5） 在原发性结肠肿瘤中高度表达，只有LGR5阳性结肠CSC能够驱动肿瘤 生长和转移。但是，CSC中LGR5的功能和机制仍然相对未知。我们 结合毒素单甲基雌激活E的LGR5靶向抗体 - 药物缀合物（ADC） 并表明它们可以破坏结肠癌细胞和异种移植物，但肿瘤最终复发。 此外，LGR5阳性结肠CSC的选择性遗传消融未能完全消除肿瘤 由于LGR5阴性癌细胞能够在处理后能够快速再生LGR5阳性细胞 终止，表明高度的癌细胞可塑性。因此，开发完全 消除原发性结肠肿瘤和转移性疾病，鉴定LGR5介导的功能和 CSC可塑性涉及的信号通路。我们报道LGR5结合R-Spondin生长因子和 功能增强Wnt/beta-catenin信号传导，这是一种在CSC中激活的必需途径。最近， 我们发现LGR5与支架蛋白IQGAP1（含有GTPase激活的IQ基序）相互作用 蛋白质1）增加结肠癌细胞中细胞细胞粘附和LGR5的敲低可显着增强 耐药性和与生存信号相关的蛋白质的激活。 LGR5诱导表达的丧失 GPR56的粘附G蛋白偶联受体GPR56的粘附力，该受体在结肠肿瘤中高度上调。在AIM 1中，我们将 确定LGR5在CSC的干性和耐药性控制中的作用和机制。我们将 研究LGR5敲除（KO）与消除LGR5阳性CSC相比如何影响肿瘤的生长， 使用患者衍生的异种移植（PDX）类型模型的转移，耐药性和癌细胞信号传导 前体内和体内。 LGR5-IQGAP1相互作用在调节定义的不同特性中的作用 CSC也将进行检查。在AIM 2中，我们将开发独特的双特异性ADC来靶向CSC可塑性。我们将 测试安全性，有效性并确定双目标治疗剂的概念证明，以同时破坏 LGR5阳性CSC和LGR5阴性癌细胞。在AIM 3中，我们将表征和验证GPR56 通过使用GPR56来描述其在肿瘤生长和耐药性中的作用，作为结肠癌的新靶标 KO结肠癌细胞系和PDX模型。这项研究将发现LGR5在 CSC并产生创新的治疗性会导致靶向干性和可塑性，以进行治疗和 根除结肠癌。