DNA-encoded bispecific T cell engagers and antibodies present long-term antitumor activity
Alfredo Perales-Puchalt, … , Kar Muthumani, David B. Weiner
Alfredo Perales-Puchalt, … , Kar Muthumani, David B. Weiner
Published July 8, 2019; First published April 18, 2019
Citation Information: JCI Insight. 2019;4(8):e126086. https://doi.org/10.1172/jci.insight.126086.
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Research Article Immunology Oncology

DNA-encoded bispecific T cell engagers and antibodies present long-term antitumor activity

Abstract

Specific antibody therapy, including mAbs and bispecific T cell engagers (BiTEs), are important new tools for cancer immunotherapy. However, these approaches are slow to develop and may be limited in their production, thus restricting the patients who can access these treatments. BiTEs exhibit a particularly short half-life and difficult production. The development of an approach allowing simplified development, delivery, and in vivo production would be an important advance. Here we describe the development of a designed synthetic DNA plasmid, which we optimized to permit high expression of an anti-HER2 antibody (HER2dMAb) and delivered it into animals through adaptive electroporation. HER2dMAb was efficiently expressed in vitro and in vivo, reaching levels of 50 μg/ml in mouse sera. Mechanistically, HER2dMAb blocked HER2 signaling and induced antibody-dependent cytotoxicity. HER2dMAb delayed tumor progression for HER2-expressing ovarian and breast cancer models. We next used the HER2dMAb single-chain variable fragment portion to engineer a DNA-encoded BiTE (DBiTE). This HER2DBiTE was expressed in vivo for approximately 4 months after a single administration. The HER2DBiTE was highly cytolytic and delayed cancer progression in mice. These studies illustrate an approach to generate DBiTEs in vivo, which represent promising immunotherapies for HER2+ tumors, including ovarian and potentially other cancers.

Authors

Alfredo Perales-Puchalt, Elizabeth K. Duperret, Xue Yang, Patricia Hernandez, Krzysztof Wojtak, Xizhou Zhu, Seang-Hwan Jung, Edgar Tello-Ruiz, Megan C. Wise, Luis J. Montaner, Kar Muthumani, David B. Weiner

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Figure 4

Generation, expression, and antitumor activity of HER2DBiTE.

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Generation, expression, and antitumor activity of HER2DBiTE. (A) Schemat...
(A) Schematic of DNA construct encoding HER2DBiTE and cartoon of BiTE engaging HER2 and the TCR. GS, glycine-serine; VH, heavy chain variable region; VL, light chain variable region; TCR, T cell receptor. (B) Western blot of human IgG from 1 μl of mouse sera electroporated with HER2DBiTE or pVax empty vector 21 and 28 days after DNA injection (triplicates, representative of 3 experiments). Numbers indicate molecular weight (kDa). (C) In vitro cytotoxicity resulting from coculture of T cells with OVCAR3 cells at different ratios (0, 1, 3, and 7) in the presence of sera from HER2DBiTE or pVax mice (2 independent experiments in triplicate). (D) In vitro cytotoxicity of sera from mice treated with HER2DBiTE after injection and electroporation of 100 μg using OVCAR3 as the target (triplicates). (E) Average growth curve of OVCAR3 tumors grafted into NSG mice treated with HER2DBiTE or empty vector (n = 10 mice per group). (F) Individual growth curves of OVCAR3 tumors grafted into NSG mice treated with HER2DBiTE or empty vector (n = 10 mice per group). Two-way ANOVA. ***P < 0.001.