P09.02 Loading of CAR-T cells with superparamagnetic iron oxide nanoparticles allows their magnetic targeting for local induction of antigen-specific anti-tumor responses

April, 04, 2024 | Select Oncology Journal Articles


Different hematological cancer types have shown promising responses to autologous chimeric antigen receptor (CAR)-T cell therapy. However, the efficacy of this treatment in solid tumors is hindered by challenges such as poor tumor infiltration, long-term retention of CAR-T cells, and systemic side effects. To address these limitations, we developed citrate-coated superparamagnetic iron oxide nanoparticles (SPIONs), which have the ability to adhere to and be taken up by T cells, thereby enabling the control of CAR-T cells through an external magnetic field (1-3). In future, magnetic guidability should help to enrich CAR-T cells in the tumor microenvironment, leading to site-specific anti-tumor responses. This study aims to investigate the influence of SPION-loading of CAR-T cells on their efficacy in anti-tumor cell responses in vitro.

Materials and Methods

T cells were isolated from peripheral blood of healthy donors and received mRNA encoding a chondroitin sulfate proteoglycan 4 (CSGP4)-specific CAR via electroporation (4, 5). The cells were then incubated with SPIONs for 4h to magnetically functionalize them. Subsequently, T cells were co-incubated with melanoma tumor cells expressing CSGP4 on their surface. Afterwards, the cells were analyzed for their antigen-specific anti-tumor responses and compared to non-loaded CAR-T cells or CSGP4-negative tumor cells by flow cytometry. Additionally, tumor cell lysis was investigated via impedance-based monitoring of cell viability and microscopic analysis of the dissolution of three-dimensional tumor spheroids.


We observed that SPION-loading did not affect the expression of activation markers, differentiation, or proliferation of CAR-T cells. Furthermore, SPION-loaded CAR-T cells retained their capability for antigen-specific tumor cell lysis over multiple days. Additionally, these CAR-T cells demonstrated the ability to be controlled by an external magnetic field, as well as infiltrating and dissolving tumor spheroids.


In summary, we demonstrated that SPION-loading did not compromise the functionality of CAR-T cells, as they were still able to perform the investigated effector functions with similar efficacy as the non-loaded control CAR-T cells. These findings underscore the potential of SPIONs in enhancing site-specific anti-tumor responses of CAR-T cells in the therapy of solid cancers in the future.


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  • Boosz et al. Cancers. 2021.

  • Pfister et al. Front Immunol. 2023.

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  • Harrer al. Int J Mol Sci. 2019.

  • F. Pfister: None. L. Löffler: None. L.R. Carnell: None. P. Boosz: None. J. Dörrie: None. N. Schaft: None. C. Alexiou: None. C. Janko: None.

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