A single proteolytic cleavage within the lower hinge of trastuzumab reduces immune effector function and in vivo efficacy
| Autor: | Zhiqiang An, Ming Fa, Anneliese Gonzalez, Hui Deng, William P. Dubinsky, Allison Oberholtzer, Ningyan Zhang, Randall J. Brezski, Xuejun Fan, Robert Jordan, William R. Strohl |
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| Rok vydání: | 2012 |
| Předmět: |
Receptor
ErbB-2 medicine.drug_class Molecular Sequence Data Biology Antibodies Monoclonal Humanized Monoclonal antibody Cell Line Mice Trastuzumab In vivo Neoplasms medicine Animals Humans Amino Acid Sequence skin and connective tissue diseases Medicine(all) Antibody-dependent cell-mediated cytotoxicity Tumor microenvironment Cell growth Receptors IgG Antibody-Dependent Cell Cytotoxicity Xenograft Model Antitumor Assays Molecular biology Matrix Metalloproteinases Disease Models Animal Proteolysis Monoclonal biology.protein Female Antibody Protein Binding Research Article medicine.drug |
| Zdroj: | Breast Cancer Research : BCR |
| ISSN: | 1465-542X |
| DOI: | 10.1186/bcr3240 |
| Popis: | Introduction Recent studies reported that human IgG antibodies are susceptible to specific proteolytic cleavage in their lower hinge region, and the hinge cleavage results in a loss of Fc-mediated effector functions. Trastuzumab is a humanized IgG1 therapeutic monoclonal antibody for the treatment of HER2-overexpressing breast cancers, and its mechanisms of action consist of inhibition of HER2 signaling and Fc-mediated antibody-dependent cellular cytotoxicity (ADCC). The objective of this study is to investigate the potential effect of proteinase hinge cleavage on the efficacy of trastuzumab using both a breast cancer cell culture method and an in vivo mouse xenograft tumor model. Methods Trastuzumab antibody was incubated with a panel of human matrix metalloproteinases, and proteolytic cleavage in the lower hinge region was detected using both western blotting and mass spectrometry. Single hinge cleaved trastuzumab (scIgG-T) was purified and evaluated for its ability to mediate ADCC and inhibition of breast cancer cell proliferation in vitro as well as anti-tumor efficacy in the mouse xenograft tumor model. Infiltrated immune cells were detected in tumor tissues by immunohistochemistry. Results scIgG-T retains HER2 antigen binding activity and inhibits HER2-mediated downstream signaling and cell proliferation in vitro when compared with the intact trastuzumab. However, scIgG-T lost Fc-mediated ADCC activity in vitro, and had significantly reduced anti-tumor efficacy in a mouse xenograft tumor model. Immunohistochemistry showed reduced immune cell infiltration in tumor tissues treated with scIgG-T when compared with those treated with the intact trastuzumab, which is consistent with the decreased ADCC mediated by scIgG-T in vitro. Conclusion Trastuzumab can be cleaved by matrix metalloproteinases within the lower hinge. scIgG-T exhibited a significantly reduced anti-tumor efficacy in vivo due to the weakened immune effector function such as ADCC. The results suggest that the lower hinge cleavage of trastuzumab can occur in the tumor microenvironment where matrix metalloproteinases often have high levels of expression and scIgG-T might compromise its anti-tumor efficacy in the clinic. However, further studies are needed to validate these hypotheses in the clinical setting. |
| Databáze: | OpenAIRE |
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