Novel Antibody-Drug Conjugate Combination Therapy for Treating Colorectal Cancer

摘要： 结直肠癌干细胞(CSCs)被认为与治疗耐药和残留复发有关。 由于它们的生存能力增强以及自我更新和分化为异质的能力而导致的疾病 肿瘤细胞的谱系。最近的治疗努力集中在针对干细胞的治疗上，以改善 治疗效果。然而，由于CSCs的可塑性和肿瘤的异质性，它正变得越来越多 显然，为了成功地消除结直肠癌(CRC)，治疗可能需要双或多个 有针对性的接近。一些报道证实，LGR5(富含亮氨酸的重复序列，包含G蛋白- 偶联受体5)在结直肠癌中高度上调，并标志着高度可塑性的CSCs。动态的相互转化 LGR5阳性的CSCs到LGR5阴性的癌细胞之间的相互作用已被证明在肿瘤进展过程中是必不可少的 和转移。我们和其他人产生了LGR5靶向抗体-药物结合物(ADC)，这些ADC具有高度的 在消除LGR5阳性结直肠肿瘤方面有效，没有重大不良反应，然而 肿瘤最终复发。这些发现表明，单独靶向LGR5阳性的CSCs可能不是 由于其可塑性，足以消除结直肠肿瘤。表观调节素(Ereg)是一种细胞表面表达的蛋白， 在结直肠癌中上调的EGFR配体，在LGR5阳性和LGR5阴性的CSCs上均高表达 癌细胞。Ereg也被证明可以促进结肠炎相关的CRC，并预测与CRC相关的肝脏 转移。有趣的是，EGFR靶向治疗已被证明增加结直肠癌中LGR5的表达 结直肠癌细胞中的模型和LGR5基因敲除增加了ERG水平。因此，LGR5的治疗靶向 Ereg/EGFR可能是消除LGR5阳性CSCs和克服可塑性的更有效的策略。 在目标1中，我们将产生抗Ereg ADC，并评估其对多发性结直肠癌的安全性和治疗效果 模特们。在目标2中，我们将确定ADC联合治疗是否可以改善治疗反应和 克服癌细胞的可塑性。我们将鉴定不同的ERG单抗，并筛选出不同的 接头有效载荷，以开发具有高特异性、亲和力和效价的最佳抗Ereg ADC。反Ereg ADC将作为单一疗法进行测试，并与抗LGR5 ADC链接到相同或不同 对照患者来源的结直肠癌异种移植模型的有效载荷。ADC也将结合以下指标进行评估 其他针对EGFR的靶向治疗。该项目将产生独特的模数转换器和创新的模数转换器 联合疗法有可能克服CSC的可塑性和耐药性，以改进结直肠癌的治疗。

ABSTRACT: Colorectal cancer stem cells (CSCs) are believed to mediate therapeutic resistance and relapse of residual disease due to their increased capacity for survival and ability to self-renew and differentiate into heterogeneous lineages of tumor cells. Recent therapeutic efforts have been focused on the targeting of CSCs to improve treatment efficacy. However, due to the plastic nature of CSCs and tumor heterogeneity, it is becoming more apparent that in order to successfully eliminate colorectal cancer (CRC), treatment may require a dual- or multi- targeted approach. Several reports have established that LGR5 (Leucine-rich repeat containing, G protein- coupled Receptor 5) is highly upregulated in CRC and marks highly plastic CSCs. The dynamic interconversion of LGR5-positive CSCs to LGR5-negative cancer cells has been shown to be essential during tumor progression and metastasis. We and others generated LGR5-targeted antibody-drug conjugates (ADCs) that were highly effective in eliminating LGR5-positive colorectal tumors without major adverse effects, however a fraction of tumors eventually relapsed. These findings suggest that targeting LGR5-positive CSCs alone may not be sufficient to eliminate colorectal tumors due to their plasticity. Epiregulin (EREG) is a cell surface expressed, EGFR ligand that is upregulated in CRC and highly expressed on both LGR5-postive CSCs and LGR5-negative cancer cells. EREG was also shown to drive colitis-associated CRC and be predictive of CRC-associated liver metastasis. Interesting, EGFR-targeted therapies have been shown to increase LGR5 expression in CRC models and LGR5 knockdown in CRC cells increased EREG levels. Thus, therapeutic targeting of both LGR5 and EREG/EGFR may be a more effective strategy to eliminate LGR5-positive CSCs and overcome plasticity. In Aim 1, we will generate anti-EREG ADCs and evaluate safety and therapeutic efficacy against multiple CRC models. In Aim 2, we will determine if ADC combination treatment can improve therapeutic response and overcome cancer cell plasticity. We will characterize different EREG monoclonal antibodies and screen different linker-payloads to develop an optimal anti-EREG ADC with high specificity, affinity, and potency. Anti-EREG ADCs will be tested as a monotherapy and in combination with anti-LGR5 ADCs linked to the same or different payloads against patient-derived xenograft models of CRC. ADCs will also be evaluated in combination with other EGFR-targeted therapies. This project will lead to the generation of unique ADCs and an innovative ADC combination therapy to potentially overcome CSC plasticity and resistance for the improved treatment of CRC.