Maass Katie F, Kulkarni Chethana, Betts Alison M, Wittrup K Dane
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
AAPS J. 2016 May;18(3):635-46. doi: 10.1208/s12248-016-9892-3. Epub 2016 Feb 24.
Antibody-drug conjugates (ADCs) are a promising class of cancer therapeutics that combine the specificity of antibodies with the cytotoxic effects of payload drugs. A quantitative understanding of how ADCs are processed intracellularly can illustrate which processing steps most influence payload delivery, thus aiding the design of more effective ADCs. In this work, we develop a kinetic model for ADC cellular processing as well as generalizable methods based on flow cytometry and fluorescence imaging to parameterize this model. A number of key processing steps are included in the model: ADC binding to its target antigen, internalization via receptor-mediated endocytosis, proteolytic degradation of the ADC, efflux of the payload out of the cell, and payload binding to its intracellular target. The model was developed with a trastuzumab-maytansinoid ADC (TM-ADC) similar to trastuzumab-emtansine (T-DM1), which is used in the clinical treatment of HER2+ breast cancer. In three high-HER2-expressing cell lines (BT-474, NCI-N87, and SK-BR-3), we report for TM-ADC half-lives for internalization of 6-14 h, degradation of 18-25 h, and efflux rate of 44-73 h. Sensitivity analysis indicates that the internalization rate and efflux rate are key parameters for determining how much payload is delivered to a cell with TM-ADC. In addition, this model describing the cellular processing of ADCs can be incorporated into larger pharmacokinetics/pharmacodynamics models, as demonstrated in the associated companion paper.
抗体药物偶联物（ADCs）是一类很有前景的癌症治疗药物，它将抗体的特异性与负载药物的细胞毒性作用结合起来。对ADCs在细胞内的加工过程进行定量理解，可以阐明哪些加工步骤对负载药物的递送影响最大，从而有助于设计更有效的ADCs。在这项工作中，我们开发了一个用于ADCs细胞加工的动力学模型，以及基于流式细胞术和荧光成像的可推广方法来对该模型进行参数化。该模型包括许多关键的加工步骤：ADCs与其靶抗原的结合、通过受体介导的内吞作用内化、ADCs的蛋白水解降解、负载药物从细胞中外排以及负载药物与其细胞内靶标的结合。该模型是基于一种与曲妥珠单抗 - 美坦新偶联物（TM - ADC）类似的曲妥珠单抗 - 依坦西普（T - DM1）开发的，T - DM1用于HER2 +乳腺癌的临床治疗。在三种高HER2表达的细胞系（BT - 474、NCI - N87和SK - BR - 3）中，我们报告了TM - ADC的内化半衰期为6 - 14小时，降解半衰期为18 - 25小时，外排速率为44 - 73小时。敏感性分析表明，内化速率和外排速率是决定TM - ADC向细胞递送多少负载药物的关键参数。此外，如相关配套论文所示，这个描述ADCs细胞加工过程的模型可以纳入更大的药代动力学/药效学模型中。
