Dataset Information

From mono- to bivalent: improving theranostic properties of target modules for redirection of UniCAR T cells against EGFR-expressing tumor cells in vitro and in vivo.

ABSTRACT: CAR-modified T cells show impressive results in clinical trials. However, cytokine release syndrome and "on-target, off-tumor" reactions represent most concerning side effects. To improve the safety of CAR-T cell therapy, we established a switchable CAR platform termed UniCAR system consisting of two components: UniCAR-modified T cells and tumor-specific target modules (TM). For treatment of EGFR+ epithelial tumors, we recently described a monovalent nanobody-based ?-EGFR TM, either expressed in bacteria or eukaryotic cells. In spite of the identical primary sequence the eukaryotic TM showed a reduced killing capability and affinity. Here we describe a novel bivalent ?-EGFR-EGFR TM. As expected, the avidity of the bivalent TM is higher than that of its monovalent counterpart. Binding of neither the monovalent ?-EGFR TM nor the bivalent ?-EGFR-EGFR TM to EGFR effected the EGF-mediated signaling. While the monovalent ?-EGFR TM could only mediate the killing of tumor cells expressing high levels of EGFR, the bivalent ?-EGFR-EGFR TM could redirect UniCAR T cells to tumor cells expressing low levels of EGFR. According to PET experiments in vivo, the increased avidity of the bivalent ?-EGFR-EGFR TM improves the enrichment at the tumor site and its use for PET imaging.

SUBMITTER: Albert S

PROVIDER: S-EPMC5986651 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature

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From mono- to bivalent: improving theranostic properties of target modules for redirection of UniCAR T cells against EGFR-expressing tumor cells in vitro and in vivo.

Albert Susann S Arndt Claudia C Koristka Stefanie S Berndt Nicole N Bergmann Ralf R Feldmann Anja A Schmitz Marc M Pietzsch Jens J Steinbach Jörg J Bachmann Michael M

Oncotarget 20180522 39

CAR-modified T cells show impressive results in clinical trials. However, cytokine release syndrome and "on-target, off-tumor" reactions represent most concerning side effects. To improve the safety of CAR-T cell therapy, we established a switchable CAR platform termed UniCAR system consisting of two components: UniCAR-modified T cells and tumor-specific target modules (TM). For treatment of EGFR+ epithelial tumors, we recently described a monovalent nanobody-based α-EGFR TM, either e ...[more]

PMID: 29876011

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Project description:BACKGROUND:Adapter chimeric antigen receptor (CAR) approaches have emerged has promising strategies to increase clinical safety of CAR T-cell therapy. In the UniCAR system, the safety switch is controlled via a target module (TM) which is characterized by a small-size and short half-life. The rapid clearance of these TMs from the blood allows a quick steering and self-limiting safety switch of UniCAR T-cells by TM dosing. This is mainly important during onset of therapy when tumor burden and the risk for severe side effects are high. For long-term UniCAR therapy, the continuous infusion of TMs may not be an optimal setting for the patients. Thus, in later stages of treatment, single infusions of TMs with an increased half-life might play an important role in long-term surveillance and eradication of residual tumor cells. Given this, we aimed to develop and characterize a novel TM with extended half-life targeting the tumor-associated carbohydrate sialyl-Tn (STn). METHODS:The extended half-life TM is composed of the STn-specific single-chain variable fragment (scFv) and the UniCAR epitope, fused to the hinge region and Fc domain of a human immunoglobulin 4 (IgG4) antibody. Specific binding and functionality of the ?STn-IgG4 TM as well as pharmacokinetic features were assessed using in vitro and in vivo assays and compared to the already established small-sized ?STn TM. RESULTS:The novel ?STn-IgG4 TM efficiently activates and redirects UniCAR T-cells to STn-expressing tumors in a target-specific and TM-dependent manner, thereby promoting the secretion of proinflammatory cytokines and tumor cell lysis in vitro and in experimental mice. Moreover, PET-imaging results demonstrate the specific enrichment of the ?STn-IgG4 TM at the tumor site, while presenting a prolonged serum half-life compared to the short-lived ?STn TM. CONCLUSION:In a clinical setting, the combination of TMs with different formats and pharmacokinetics may represent a promising strategy for retargeting of UniCAR T-cells in a flexible, individualized and safe manner at particular stages of therapy. Furthermore, as these molecules can be used for in vivo imaging, they pose as attractive candidates for theranostic approaches.

Project description:Interactions of chromatin with bivalent immunoglobin nucleosome-binding antibodies and their monovalent (papain-derived) antigen-binding fragment analogs are useful probes for examining chromatin conformational states. To help interpret antibody-chromatin interactions and explore how antibodies might compete for interactions with chromatin components, we incorporate coarse-grained PL2-6 antibody modeling into our mesoscale chromatin model. We analyze interactions and fiber structures for the antibody-chromatin complexes in open and condensed chromatin, with and without H1 linker histone (LH). Despite minimal and transient interactions at physiological salt, we capture significant differences in antibody-chromatin complex configurations in open fibers, with more intense interactions between the bivalent antibody and chromatin compared to monovalent antigen-binding fragments. For these open chromatin fiber morphologies, antibody binding to histone tails is increased and compaction is greater for bivalent compared to monovalent and antibody-free systems. Differences between monovalent and bivalent binding result from antibody competition with internal chromatin fiber components (nucleosome core and linker DNA) for histone tail (H3, H4, H2A, H2B) interactions. This antibody competition for tail contacts reduces tail-core and tail-linker interactions and increases tail-antibody interactions. Such internal structural changes in open fibers resemble mechanisms of LH condensation, driven by charge screening and entropy changes. For condensed fibers at physiological salt, the three systems are much more similar overall, but some subtle tail interaction differences can be noted. Adding LH results in less-dramatic changes for all systems, except that the bivalent complex at physiological salt shows cooperative effects between LH and the antibodies in condensing chromatin fibers. Such dynamic interactions that depend on the internal structure and complex-stabilizing interactions within the chromatin fiber have implications for gene regulation and other chromatin complexes such as with LH, remodeling proteins, and small molecular chaperones that bind and modulate chromatin structure.

Dataset Information

From mono- to bivalent: improving theranostic properties of target modules for redirection of UniCAR T cells against EGFR-expressing tumor cells in vitro and in vivo.

Publications

From mono- to bivalent: improving theranostic properties of target modules for redirection of UniCAR T cells against EGFR-expressing tumor cells <i>in vitro</i> and <i>in vivo</i>.

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OmicsDI is part of the ELIXIR infrastructure

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Dataset Information

From mono- to bivalent: improving theranostic properties of target modules for redirection of UniCAR T cells against EGFR-expressing tumor cells in vitro and in vivo.

Publications

From mono- to bivalent: improving theranostic properties of target modules for redirection of UniCAR T cells against EGFR-expressing tumor cells &lt;i&gt;in vitro&lt;/i&gt; and &lt;i&gt;in vivo&lt;/i&gt;.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

From mono- to bivalent: improving theranostic properties of target modules for redirection of UniCAR T cells against EGFR-expressing tumor cells <i>in vitro</i> and <i>in vivo</i>.