Development of antibody-based cancer therapies

硫酸肝素蛋白多糖（HSPGs）是发育和疾病过程中信号转导通路的重要调节剂。它们是通过添加一个或几个糖胺聚糖链来修饰的细胞表面蛋白质。由于几种HSPGs在某些肿瘤类型中的高表达，已被认为是癌症治疗的候选靶点。我们已经生成了针对glypican-3 （GPC3）治疗肝细胞癌（HCC）的人源和人源抗体。我们生成了识别GPC3中c -末端位点（511-560）的小鼠单克隆抗体（例如YP7） [Phung et al., mab, PMID 22820551, 2012]。此外，我们还生成了两种人单克隆抗体（HN3和HS20）。HN3是一种人重链抗体，可识别GPC3核心蛋白中独特的构象表位，并抑制HCC细胞的增殖。HN3作用的潜在机制涉及肝癌细胞中Yap信号的抑制。HS20优先识别GPC3的硫酸肝素链。人抗体破坏Wnt3a和GPC3的相互作用，抑制Wnt/ β -catenin信号传导。新抗体对小鼠肝癌异种移植肿瘤的生长有显著的抑制作用，并显示出作为治疗候选物的潜力。2014财年，我们总结了针对GPC3肝癌治疗的人单克隆抗体的开发工作，并发表了两篇针对HN3和HS20人抗体的研究报告[Feng et al.， PNAS, PMID 23471984, 2013；高等，肝病学，PMID 24492943, 2014]和一篇关于GPC3治疗性抗体开发的特邀综述文章[Feng and Ho， FEBS Letters, PMID 24140348, 2014]。项目2：靶向间皮瘤、卵巢癌、胆管癌间皮素在间皮瘤、卵巢癌、胰腺癌、肺癌、胃癌、结直肠癌、乳腺癌、胆管癌中表达。间皮素与MUC16（也称为CA125）之间的分子相互作用可能促进肿瘤的植入和扩散。我们在间皮素中发现MUC16的功能结合域（命名为IAB， 296-359） [Kaneko et al.， JBC, PMID 19075018, 2009]。我们制备了两种间皮素特异性的人单克隆抗体。HN1人抗体破坏间皮素- muc16相互作用，引发针对肿瘤细胞的抗体依赖细胞介导的细胞毒性（ADCC）。SD1是一种人重链抗体，可识别间皮素中靠近细胞表面的独特位点（539-588），并对肿瘤细胞表现出补体依赖性细胞毒性（CDC）和ADCC。这种新的人类抗体显示出作为癌症治疗候选药物的潜力。2014财年，我们总结了SD1抗体的研究并发表了一篇研究文章[Tang et al., Molecular Cancer Therapeutics, PMID 23371858, 2013]。此外，我们还与Ira Pastan （NCI）合作开发了一种基于IL12和SS1 Fv的免疫细胞因子。这种新的免疫细胞因子抑制小鼠体内生长的人类间皮瘤，为间皮瘤靶向癌症治疗提供了一种有吸引力的补充。2014财年，我们发表了针对间皮素阳性肿瘤的免疫细胞因子研究报告[Kim et al., PLoS One, PMID 24260587, 2013]。

Project 1: Targeting glypican-3 in hepatocellular carcinoma Heparan sulfate proteoglycans (HSPGs) are important modulators of signal transduction pathways during development and disease. They are cell-surface proteins that are modified by the addition of one or several glycosaminoglycan chains. Several HSPGs have been suggested as candidate targets for cancer therapy because of their high expression in certain tumor types. We have generated human and humanized antibodies targeting glypican-3 (GPC3) in hepatocellular carcinoma (HCC). We generated mouse monoclonal antibodies (e.g. YP7) that recognize a C-terminal site (511-560) in GPC3 [Phung et al., MAbs, PMID 22820551, 2012] . Furthermore, we generated two human monoclonal antibodies (HN3 and HS20). HN3 is a human heavy-chain antibody that recognizes a unique conformational epitope in the core protein of GPC3 and inhibits proliferation of HCC cells. The underlying mechanism of HN3 action involves inhibition of Yap signaling in liver cancer cells. HS20 preferentially recognizes the heparan sulfate chains of GPC3. The human antibody disrupts the interaction of Wnt3a and GPC3 and inhibits Wnt/beta-catenin signaling. The new antibodies exhibit significant inhibition of HCC xenograft tumor growth in mice and show potential for use as therapeutic candidates. In FY14, we summarized our work on the development of human monoclonal antibodies targeting GPC3 for liver cancer therapy and published two research reports about the HN3 and HS20 human antibodies [Feng et al., PNAS, PMID 23471984, 2013; Gao et al., Hepatology, PMID 24492943, 2014] and one invited review article about GPC3 therapeutic antibody development [Feng and Ho, FEBS Letters, PMID 24140348, 2014]. Project 2: Targeting mesothelin in mesothelioma, ovarian cancer and cholangiocarcinoma Mesothelin is expressed in mesothelioma, ovarian cancer, pancreatic cancer, lung cancer, gastric cancer, colorectal cancer, breast cancer and cholangiocarcinoma. The molecular interaction between mesothelin and MUC16 (also known as CA125) may facilitate the implantation and spread of tumors. We identified the functional binding domain (named IAB, 296-359) in mesothelin for MUC16 [Kaneko et al., JBC, PMID 19075018, 2009]. We generated two human monoclonal antibodies specific for mesothelin. The HN1 human antibody disrupts the mesothelin-MUC16 interaction and elicits antibody-dependent cell-mediated cytotoxicity (ADCC) against tumor cells. SD1 is a human heavy-chain antibody that recognizes a unique site (539-588) in mesothelin close to the cell surface and exhibits complement-dependent cytotoxicity (CDC) as well as ADCC against tumor cells. The new human antibodies show potential for use as cancer therapeutic candidates. In FY14, we summarized the SD1 antibody study and published a research article [Tang et al., Molecular Cancer Therapeutics, PMID 23371858, 2013]. In addition, we have also developed an immunocytokine based on IL12 and the SS1 Fv in collaboration with Ira Pastan (NCI). The new immunocytokine inhibits human mesothelioma grown in mice and provides an attractive addition to mesothelin-targeted cancer therapies. In FY14, we published our report about the immunocytokine targeting mesothelin-positive tumors [Kim et al., PLoS One, PMID 24260587, 2013].