Antibody targeting of ADAM8 for treatment of triple-negative breast cancer

 描述(申请人提供)：三阴性乳腺癌(TNBCs)约占乳腺癌死亡的25%，缺乏有针对性的治疗。Sonenshein博士、Mineva博士和Romagnoli博士以及他们的同事最近发现非必需的细胞表面蛋白ADAM8(A去整合素和金属蛋白酶8)是乳腺癌生长和转移的关键促进因素，并证实它是TNBC抗体治疗的靶点。ADAM8mRNA在TNBCs中高表达，其水平与患者预后不良相关。ADAM8蛋白在34%的原发TNBCs和一半的乳腺癌患者转移瘤中表达，而在邻近的正常乳腺组织中不表达。来自ADAM8基因敲除的TNBC细胞的原位肿瘤仅生长到可触摸到的大小，并产生极少的循环肿瘤细胞和脑转移。ADAM8的金属蛋白酶(MP)和去整合素(DI)结构域分别通过释放促血管生成因子和激活β-1整合素在肿瘤细胞的生长和扩散中起关键作用。在原位移植模型中，使用试剂级商品化抗ADAM8鼠单抗MAB1031(研发)，具有针对MP和DI结构域的体外拮抗活性，在1.5 mg/kg时，与对照同型相合的IgG2B相比，原发TNBC肿瘤负荷减少了70%。MAB1031还大大减少了先前存在的肿瘤向大脑和肺部的扩散，提供了概念证明，即可以制备双重拮抗剂mAb，并且这两个区域都可以在体内进行基于抗体的治疗。因此，我们假设基于ADAM8抗体的治疗对表达这种跨膜蛋白的TNBC患者构成了一种有效的治疗方法。2014年5月13日，Sonenshein、Mineva和Romagnoli博士以及塔夫茨大学提交了PCT专利申请PCT/US14/37857，申请内容包括靶向ADAM8MP和DI结构域用于治疗乳腺癌和其他ADAM8驱动的癌症，包括胰腺癌。2014年10月，这三位发明者创立了Adecto PharmPharmticals，Inc.(AP)，目标是开发用于治疗TNBC和转移性乳腺癌的ADAM8特异性抗体作为初步适应症。在这一第一阶段的STTR应用中，AP将与Sonenshein实验室(SL)密切合作，制备针对人类ADAM8的鼠单抗，抑制其MP和DI结构域，并在小鼠身上进行中试临床前试验。其具体目标是：(1)分离一组具有MP和DI结构域拮抗剂活性的HuADAM8单抗；(2)通过细胞分析确定最有效的拮抗剂单抗；(3)对两种最有效的ADAM8拮抗剂单抗进行体内中试测试，以抑制先前存在的荧光素酶标记的MDA-MB-231细胞来源肿瘤的生长和转移转移。我们认为，基于ADAM8抗体的治疗有可能彻底改变TNBC患者的治疗，并降低与转移性乳腺癌相关的死亡率，因此将成为TNBC护理的新组成部分。

 DESCRIPTION (provided by applicant): Triple-negative breast cancers (TNBCs) account for ~25% of breast cancer deaths and lack targeted therapies. Drs. Sonenshein, Mineva and Romagnoli and their co-workers recently identified the non-essential, cell surface protein ADAM8 (A Disintegrin and Metalloprotease 8) as a pivotal promoter of breast tumor growth and metastasis, and validated it as a target of antibody therapy for TNBC. ADAM8 mRNA was highly expressed in TNBCs, and its level correlated with poor patient outcome. ADAM8 protein was present in 34% of primary TNBCs, and half of all breast cancer patient-derived metastases, but absent in adjacent normal breast tissues. Orthotopic tumors from ADAM8 knockdown TNBC cells grew only to a palpable size and generated very few circulating tumor cells and brain metastases. The Metalloproteinase (MP) and Disintegrin (DI) domains of ADAM8 were critical in tumor growth and dissemination through release of pro-angiogenic factors and activation of β1-integrin on cancer cells, respectively. Treatment with a reagent grade commercial anti-ADAM8 mouse monoclonal antibody (mAb) MAB1031 (R&D), with in vitro antagonist activity against both the MP and DI domains, reduced primary TNBC tumor burden by 70% at 1.5 mg/kg vs control isotype-matched IgG2B in an orthotopic model when started at the time of cell implantation. MAB1031 also profoundly reduced dissemination of pre-existing tumors to the brain and lungs, providing proof-of-concept that a dual antagonist mAb can be prepared and that both domains are accessible to antibody-based therapy in vivo. Thus, we hypothesize that ADAM8 antibody-based treatment constitutes an effective therapy for TNBC patients expressing this transmembrane protein. A PCT patent application PCT/US14/37857 was filed May 13, 2014 by Drs. Sonenshein, Mineva and Romagnoli, and Tufts University, with claims including the targeting of ADAM8 MP and DI domains for treatment of breast and other ADAM8-driven cancers, including pancreatic adenocarcinomas. In October 2014, Adecto Pharmaceuticals, Inc (AP) was founded by the three inventors with the goal of developing ADAM8-specific antibodies for the treatment of TNBC and metastatic breast cancer as the initial indications. In this Phase 1 STTR application, AP will work closely with the Sonenshein lab (SL) to prepare mouse mAbs specific for human ADAM8 that inhibit both its MP and DI domains and perform pilot preclinical testing in mice. The specific aims are to: (1) Isolate a panel of mAbs specific for HuADAM8 with MP and DI domain antagonist activity; (2) Identify the most effective antagonist mAbs using cell based assays; (3) Perform pilot in vivo testing of the ability of the two most effective ADAM8 antagonist mAbs to inhibit growth and metastatic dissemination of pre-existing luciferase-tagged MDA-MB-231 cell-derived tumors. We propose that ADAM8 antibody-based therapy has the potential to revolutionize the treatment of TNBC patients, and reduce the mortality associated with metastatic breast cancer and thus will become a new component of care for TNBC.