O-Glycan-dependent Immunotherapy for Cancer

摘要 几十年来，癌症的治疗一直依靠手术切除、化疗和/或放射治疗。 最近，一些基于免疫的治疗方法为癌症的治疗提供了有前途的新方法。 两种最有效的免疫疗法是基于单抗(MAb)的双特异性蛋白(例如，双抗)。 特异性T细胞激活物(BITE)和工程嵌合抗原受体T细胞(CAR T)。两者都是按照 诱导T细胞介导的对癌细胞的杀伤并显示出显著的临床活性，完全 B细胞恶性肿瘤的有效率高达90%。然而，应用这两种治疗方法 对绝大多数癌症类型来说，是由多种因素预防的。首先，只有少量的 已知的细胞表面蛋白对癌症具有足够的特异性，可以安全地通过抗体进行靶向。这是 实体癌尤其如此，与血液系统恶性肿瘤不同，健康细胞的丧失不可能是 很容易被干细胞前体细胞补充。第二，由于每个单独的双特异蛋白和/或CAR T细胞 只能针对一种癌症类型，需要为每种类型开发不同的双特异性和/或CAR T细胞 癌症类型。这大大增加了开发时间和成本。第三，任何一种疗法都不能有效地 靶向已知最丰富和最广泛表达的癌症抗原，即肿瘤相关癌 抗原(TACA)。许多癌症特异性抗原不是蛋白质，而是复杂的碳水化合物，具有 在正常组织中表达有限或不表达。事实上，糖基化改变几乎是癌症的普遍特征。 然而，针对复杂碳水化合物的单抗的产生已被证明是非常 具有挑战性，极大地限制了它们作为癌症免疫治疗靶点的有效性。在此，我们建议 解决这些问题，开发一种针对碳水化合物的新型免疫疗法 绝大多数实体癌和造血癌常见的抗原，但在正常组织中不表达 细胞。我们将这些分子称为糖依赖T细胞招募器(GlyTR)技术。 关键的是，GlyTR技术不利用抗体来靶向碳水化合物癌症抗原。初步 数据表明，O-连接的碳水化合物靶向双特异性GlyTR蛋白诱导T细胞依赖 在体外杀死人类癌细胞，而不会偏离靶点杀死正常细胞。为了进一步发展这项技术， 我们提出了以下目标。Aim 1优化O-连接糖链靶向GlyTR双特异性蛋白 活动和药物开发。目的2探索优化的O-连接葡聚糖的有效性和安全性 靶向GlyTR双特异性蛋白。如果成功，这项工作将导致对整个新的IND的研究 一类可靶向多种实体和血液性癌症的免疫治疗癌症杀伤剂 毒性最小。

Abstract For decades, the treatment of cancer has relied on surgical resection, chemotherapy and/or radiotherapy. Recently, a number of immune based therapies have provided promising new approaches for cancer treatment. The two most potent immunotherapies are monoclonal antibody (mAB) based bi-specific proteins (eg Bi- specific T cell engagers – BiTE) and engineered Chimeric Antigen Receptor T cells (CAR T). Both act by inducing T cell mediated killing of cancer cells and have shown remarkable clinical activity, with complete response rates as high as ~90% for B cell malignancies. However, applying these two therapeutic approaches to the vast majority of cancer types is prevented by multiple factors. First, there are only a small number of known cell-surface proteins that are sufficiently specific to cancer to safely allow targeting by antibodies. This is particularly true for solid cancers, where unlike hematopoietic malignancies, loss of healthy cells cannot be readily replenished by stem cell progenitors. Second, as each individual bi-specific protein and/or CAR T cell can only target a single cancer type, different bi-specific and/or CAR T cells will need to be developed for each cancer type. This greatly increases development time and costs. Third, neither therapy is able to effectively target the most abundant and widely expressed cancer antigens known, namely Tumor associated cancer antigens (TACA's). Many cancer specific antigens are not proteins, but rather complex carbohydrates that have limited or no expression in normal tissues. Indeed, altered glycosylation is a near universal feature of cancer. However, generation of monoclonal antibodies specific to complex carbohydrates has proven to be very challenging, greatly limiting their usefulness as targets for cancer immunotherapy. Here we propose to address these issues and develop a novel class of immunotherapeutics that target a carbohydrate antigen common to the vast majority of solid and hematopoietic cancers but not expressed in normal cells. We have termed these molecules as Glycan-dependent T cell Recruiter (GlyTR) technology. Critically, GlyTR technology does not utilize antibodies to target carbohydrate cancer antigens. Preliminary data demonstrates that an O-linked carbohydrate targeted bi-specific GlyTR protein induces T cell dependent killing of human cancer cells in vitro without off-target killing of normal cells. To further develop this technology, we propose the following Aims. Aim 1 optimizes an O-linked glycan targeted GlyTR bi-specific protein for activity and drug development. Aim 2 explores the efficacy and safety of the optimized O-linked glycan targeted GlyTR bi-specific protein. If successful, this work will lead to IND enabling studies of an entire new class of immunotherapeutic cancer killing therapeutics that can target multiple solid and hematopoietic cancers with minimal toxicity.