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

 描述（由申请人提供）：三阴性乳腺癌（TNBC）占乳腺癌死亡的约25%，缺乏靶向治疗。Sonenshein，Mineva和Romagnoli博士及其同事最近确定了非必需的细胞表面蛋白ADAM 8（一种去整合素和金属蛋白酶8）作为乳腺肿瘤生长和转移的关键促进剂，并验证了它作为TNBC抗体治疗的靶点。ADAM 8 mRNA在TNBC中高度表达，其水平与患者预后不良相关。ADAM 8蛋白存在于34%的原发性TNBC和一半的乳腺癌患者来源的转移灶中，但在相邻的正常乳腺组织中不存在。来自ADAM 8敲减TNBC细胞的原位肿瘤仅生长至可触知的大小，并且产生非常少的循环肿瘤细胞和脑转移。ADAM 8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癌细胞上的β1-整合素而在肿瘤生长和扩散中起关键作用。在原位模型中，当在细胞植入时开始时，用对MP和DI结构域具有体外拮抗剂活性的试剂级商业抗ADAM 8小鼠单克隆抗体（mAb）MAB 1031（R&D）治疗，与对照同种型匹配的IgG 2B相比，在1.5 mg/kg下使原发性TNBC肿瘤负荷降低70%。MAB 1031还显著减少了既存肿瘤向脑和肺的扩散，提供了可以制备双重拮抗剂mAb的概念验证，并且这两个结构域都可用于体内基于抗体的治疗。因此，我们假设基于ADAM 8抗体的治疗构成了表达这种跨膜蛋白的TNBC患者的有效疗法。PCT专利申请PCT/US 14/37857由Sonenshein、Mineva和Romagnoli博士以及塔夫茨大学于2014年5月13日提交，其权利要求包括靶向ADAM 8 MP和DI结构域用于治疗乳腺癌和其他ADAM 8驱动的癌症，包括胰腺腺癌。2014年10月，Adecto Pharmaceuticals，Inc（AP）由三位发明人创立，目标是开发用于治疗TNBC和转移性乳腺癌的ADAM 8特异性抗体作为初始适应症。在这项1期STTR申请中，AP将与Sonenshein实验室（SL）密切合作，制备特异性针对人ADAM 8的小鼠mAb，抑制其MP和DI结构域，并在小鼠中进行初步临床前测试。具体目标是：（1）分离一组对HuADAM 8具有MP和DI结构域拮抗剂活性的特异性mAb;（2）使用基于细胞的测定法鉴定最有效的拮抗剂mAb;（3）对两种最有效的ADAM 8拮抗剂mAb抑制预先存在的经内切酶标记的MDA-MB-231细胞衍生肿瘤的生长和转移性播散的能力进行初步体内测试。我们认为，基于ADAM 8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.