Novel Antibody-Drug Conjugate Combination Therapy for Treating Colorectal Cancer

摘要： 结直肠癌干细胞（CSC）被认为可以介导治疗耐药性和残留的复发 由于它们的生存能力和自我更新能力以及分化成异质性的能力增强而导致疾病 肿瘤细胞谱系。最近的治疗工作集中在靶向 CSC 以改善 治疗效果。然而，由于CSC的可塑性和肿瘤异质性，它变得越来越 显然，为了成功消除结直肠癌（CRC），治疗可能需要双重或多重治疗。 有针对性的方法。一些报告已经证实 LGR5（富含亮氨酸重复序列，G 蛋白- 耦合受体 5) 在 CRC 中高度上调，标志着高度可塑的 CSC。动态相互转换 LGR5 阳性 CSC 转化为 LGR5 阴性癌细胞已被证明在肿瘤进展过程中至关重要 和转移。我们和其他人生成了针对 LGR5 的抗体药物偶联物 (ADC)，该偶联物具有高度的 能有效消除 LGR5 阳性结直肠肿瘤，且无重大副作用，但只有一小部分 肿瘤最终复发。这些发现表明，单独针对 LGR5 阳性 CSC 可能并不能 由于其可塑性，足以消除结直肠肿瘤。上皮调节蛋白（EREG）是细胞表面表达的， EGFR 配体在 CRC 中上调，并在 LGR5 阳性 CSC 和 LGR5 阴性 CSC 上高表达 癌细胞。 EREG 还被证明可以驱动结肠炎相关的 CRC，并可预测 CRC 相关的肝脏 转移。有趣的是，EGFR 靶向疗法已被证明可以增加 CRC 中 LGR5 的表达 模型和 CRC 细胞中 LGR5 敲除增加了 EREG 水平。因此，LGR5 的治疗靶向 EREG/EGFR可能是消除LGR5阳性CSC并克服可塑性的更有效策略。 在目标 1 中，我们将生成抗 EREG ADC，并评估针对多种 CRC 的安全性和治疗效果 模型。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以及 克服癌细胞的可塑性。我们将表征不同的 EREG 单克隆抗体并筛选不同的 连接器有效负载开发具有高特异性、亲和力和效力的最佳抗 EREG ADC。抗EREG ADC 将作为单一疗法以及与相同或不同的抗 LGR5 ADC 组合进行测试 针对患者来源的 CRC 异种移植模型的有效负载。 ADC 还将结合以下因素进行评估： 其他 EGFR 靶向疗法。该项目将导致独特 ADC 和创新 ADC 的产生 联合疗法有可能克服 CSC 的可塑性和耐药性，从而改善 CRC 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.