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.

摘要： 肿瘤起始或癌症干细胞(CSCs)与耐药、转移和复发有关， 使CSCs成为癌症有效治疗的主要障碍。最近的研究明确地表明 确定了成体干细胞标志物LGR5(富含亮氨酸重复序列，G蛋白偶联受体5) 在原发结肠肿瘤中高表达，只有LGR5阳性的结肠CSCs能够驱动肿瘤 生长和转移。然而，LGR5在CSCs中的作用和机制还相对不清楚。我们 产生含有毒素单甲基金黄色E的LGR5靶向抗体-药物结合物(ADC) 并表明它们可以摧毁结肠癌细胞和异种移植物，但肿瘤最终复发。 此外，选择性基因消融LGR5阳性的结肠CSCs未能完全根除肿瘤。 由于LGR5阴性的癌细胞在治疗后能够快速再生LGR5阳性细胞 终止，表明癌细胞具有高度的可塑性。因此，要开发出完全 根除原发结肠肿瘤和转移性疾病，关键是确定LGR5介导的功能和 参与CSC可塑性的信号通路。我们报道了LGR5结合R-响应蛋白生长因子和 增强Wnt/β-catenin信号的功能，这是CSCs中激活的一个基本途径。最近， 我们已经发现LGR5与支架蛋白IQGAP1(IQ基序包含GTP酶激活)相互作用 蛋白1)增加结肠癌细胞间黏附，LGR5基因敲除显著增强 耐药和与生存信号相关的蛋白质的激活。LGR5诱导表达缺失 黏附G蛋白偶联受体GPR56，它在结肠肿瘤中高度上调。在目标1中，我们将 确定LGR5在控制CSCs的干性和耐药性中的作用和机制。我们会 研究LGR5基因敲除(KO)与消除LGR5阳性CSCs对肿瘤生长的影响。 使用患者来源的异种移植(PDX)有机物模型的转移、耐药和癌细胞信号 体外和体内。LGR5-IQGAP1相互作用在调节不同属性中的作用 CSC也将接受检查。在目标2中，我们将开发针对CSC可塑性的独特的双特异性ADC。我们会 测试安全性、有效性并建立双靶向疗法的概念验证以同时摧毁 LGR5阳性的CSCs和LGR5阴性的癌细胞。在目标3中，我们将描述和验证GPR56 通过GPR56描述其在肿瘤生长和耐药性中的作用，作为结肠癌的新靶点 KO结肠癌细胞株和PDX模型。本研究将揭示LGR5在脑缺血再灌注损伤中的作用和机制 CSCs并产生创新的治疗导向，为治疗和治疗提供靶向干细胞和可塑性 根治结肠癌。