Engaging immunosuppressive myeloid cells in the TME for the treatment of pancreatic cancer

摘要 虽然过去十年的标志是肿瘤免疫治疗的巨大成功，但很少有人 为胰腺癌患者提供了显著的益处。该项目的长期目标是开发 用于胰腺癌临床治疗的治疗上有用的免疫疗法。总体目标 在本申请中的目的是（i）表征MARCO在TME中的作用，（ii）评价治疗功效 和（iii）用阻断该受体的抗体改善胰腺TME内的抗原呈递， 靶向MARCO和CD 40的Fc增强的抗体的组合。我们的中心假设是胰腺癌 癌症使肿瘤相关巨噬细胞复极化为M2表型，这可以通过以下方式逆转： MARCO与抗体结合，从而促进抗肿瘤反应。该项目的理由 确定表达MARCO的TAM在胰腺癌中的免疫抑制作用， 可能提供一个强大的科学框架，从而可以开发新的免疫疗法。中央 将通过追求三个具体目标来检验假设：1）开发用于癌症的抗人TAM抗体 免疫治疗，并建立新的测定法，用于大规模评估抗TAM抗体，2）定义的作用， MARCO在胰腺癌TAM极化中的作用，以及3）在胰腺癌TAM复极化中增强TAM 使用Fc增强的CD 40激动剂抗体2141-V11单独或与抗-CD 40抗体2141-V11组合的癌症TME， hMARCO antibodies..在第一个目标下，将产生针对人MARCO的新型抗体， 针对Fc-受体结合进行优化。在第二个目标中，小鼠经基因工程改造以表达人MARCO 将研究它们在胰腺癌TME中的作用。在表征免疫细胞表达后， MARCO可以通过抗体治疗靶向，将测试一组抗体变体以确定 最佳体内活性的Fc要求。MARCO表达和免疫特性 还将在人胰腺癌标本中评估微环境。最后，在第三个目标中， 利用目标1和2中获得的知识，测试靶向胰腺肿瘤髓样轴的新组合。 在此，将单独或与以下组合测试Fc增强的抗CD 40抗体的抗肿瘤活性： 胰腺癌模型中的抗MARCO抗体。本申请中提出的研究具有创新性， 在研究者看来，因为它专注于定义髓样细胞上的新途径， 胰腺癌的免疫抑制性TME，同时通过Fc- 工程.这项拟议中的研究意义重大，因为它有望提供强有力的科学依据 用于开发巨噬细胞靶向免疫疗法。最终，这些知识有可能 为将创新疗法转化为胰腺癌的治疗提供了新的机会。

ABSTRACT Although the past decade was marked by the tremendous success of immunotherapeutics in oncology, few have provided significant benefit to patients with pancreatic cancer. The long-term goal of this project is to develop therapeutically useful immunotherapies for the clinical treatment of pancreatic cancer. The overall objectives in this application are to (i) characterize the role for MARCO in the TME, (ii) to evaluate the therapeutic efficacy of antibodies blocking this receptor, and (iii) improve antigen presentation within the pancreatic TME with a combination of Fc-enhanced antibodies targeting MARCO and CD40. Our central hypothesis is that pancreatic cancer repolarizes tumor associated macrophages to an M2 phenotype an this can be reversed through engagement of MARCO with antibodies, therefore promoting anti-tumor responses. The rationale for this project is that a determination of the immunosuppressive role of TAMs expressing MARCO in pancreatic cancer will likely offer a strong scientific framework whereby new immunotherapies can be developed. The central hypothesis will be tested by pursuing three specific aims: 1) Develop anti-human TAM antibodies for cancer immunotherapy and set up novel assays for large-scale evaluation of anti-TAM antibodies, 2) Define the role for MARCO in the polarization of TAMs in pancreatic cancer, and 3) Augment TAM repolarization in the pancreatic cancer TME using the Fc-enhanced CD40 agonist antibody 2141-V11, alone or in combination with anti- hMARCO antibodies.. Under the first aim, novel antibodies will be generated against human MARCO and optimized for Fc-receptor binding. In the second Aim, mice genetically engineered to express human MARCO will be studied for their role in the TME of pancreatic cancer. Following characterization immune cells expressing MARCO that can be targeted by antibody therapy, a panel of antibody variants will be tested to determine the Fc-requirements for optimal in vivo activity. MARCO expression and characterization of the immune microenvironment will also be evaluated in human pancreatic cancer specimens. Finally, in the third aim, we will use knowledge gained in Aims 1 and 2 to test novel combinations targeting the myeloid axis in pancreatic tumors. Here, the anti-tumor activity of the Fc-enhanced anti-CD40 antibody will be tested alone or in combination with anti-MARCO antibodies in pancreatic cancer models. The research proposed in this application is innovative, in the investigator’s opinion, because it focuses on defining novel pathways on myeloid cells contributing to the immune suppressive TME of pancreatic cancer, while identifying lead therapeutic candidates through Fc- engineering. The proposed research is significant because it is expected to provide strong scientific justification for the development of macrophage targeting immunotherapies. Ultimately, such knowledge has the potential of offering new opportunities for the translation of innovative therapies to the treatment of pancreatic cancer.