Data from: Development and evaluation of a fluorescent antibody-drug conjugate for molecular imaging and targeted therapy of pancreatic cancer

Antibodies are widely available and cost-effective research tools in life science, and antibody conjugates are now extensively used for targeted therapy, immunohistochemical staining, or in vivo diagnostic imaging of cancer. Significant advances in site-specific antibody labeling technologies have enabled the production of highly characterized and homogenous conjugates for biomedical purposes, and some recent studies have utilized site-specific labeling to synthesize bifunctional antibody conjugates with both imaging and drug delivery properties. While these advances are important for the clinical safety and efficacy of such biologics, these techniques can also be difficult, expensive, and time-consuming. Furthermore, antibody-drug conjugates (ADCs) used for tumor treatment generally remain distinct from conjugates used for diagnosis. Thus, there exists a need to develop simple dual-labeling methods for efficient therapeutic and diagnostic evaluation of antibody conjugates in pre-clinical model systems. Here, we present a rapid and simple method utilizing commercially available reagents for synthesizing a dual-labeled fluorescent ADC. Further, we demonstrate the fluorescent ADC’s utility for simultaneous targeted therapy and molecular imaging of cancer both in vitro and in vivo. Employing non-site-specific, amine-reactive chemistry, our novel biopharmaceutical theranostic is a monoclonal antibody specific for a carcinoembryonic antigen (CEA) biomarker conjugated to both paclitaxel and a near-infrared (NIR), polyethylene glycol modified (PEGylated) fluorophore (DyLight™ 680-4xPEG). Using in vitro systems, we demonstrate that this fluorescent ADC selectively binds a CEA-positive pancreatic cancer cell line (BxPC-3) in immunofluorescent staining and flow cytometry, exhibits efficient internalization kinetics, and is cytotoxic. Model studies using a xenograft of BxPC-3 cells in athymic mice also show the fluorescent ADC’s efficacy in detecting tumors in vivo and inhibiting tumor growth more effectively than equimolar amounts of unconjugated drug. Overall, our results demonstrate that non-selective, amine-targeting chemistry is an effective dual-labeling method for synthesizing and evaluating a bifunctional fluorescent antibody-drug conjugate, allowing concurrent detection, monitoring and treatment of cancer.

抗体是生命科学领域中易得且经济高效的研究工具，而抗体偶联物目前已被广泛应用于癌症的靶向治疗、免疫组织化学染色以及体内诊断成像。位点特异性抗体标记技术的重大进展，使得制备用于生物医学用途的高表征性、均一性偶联物成为可能；近期已有多项研究利用该技术合成兼具成像与药物递送功能的双功能抗体偶联物。尽管这些进展对这类生物制剂的临床安全性与有效性至关重要，但相关技术往往操作复杂、成本高昂且耗时较长。此外，用于肿瘤治疗的抗体-药物偶联物（antibody-drug conjugate, ADC）通常与用于诊断的偶联物界限分明。因此，亟需开发简便的双标记方法，以在临床前模型系统中高效评估抗体偶联物的治疗与诊断效能。本研究提出一种利用市售试剂的快速简便方法，用于合成双标记荧光抗体-药物偶联物。此外，本研究验证了该荧光ADC在体外与体内环境中，同时实现癌症靶向治疗与分子成像的应用潜力。本研究采用非位点特异性胺反应化学策略，构建了一款新型诊疗一体化生物制剂：靶向癌胚抗原（CEA）生物标志物的单克隆抗体，分别与紫杉醇以及经聚乙二醇修饰（PEGylated）的近红外（NIR）荧光团DyLight™ 680-4xPEG偶联。通过体外实验体系，本研究证实该荧光ADC可在免疫荧光染色与流式细胞术检测中，特异性结合CEA阳性胰腺癌细胞系BxPC-3，展现出高效的内化动力学特征，并具有细胞毒性。利用BxPC-3细胞异种移植裸鼠模型开展的体内实验同样证实，相较于等摩尔剂量的未偶联药物，该荧光ADC在体内肿瘤检测与肿瘤生长抑制方面均表现出更优的效能。综上，本研究结果表明，非选择性胺靶向化学策略是一种有效的双标记方法，可用于合成与评估双功能荧光抗体-药物偶联物，从而实现癌症的同步检测、监测与治疗。