Development of a new immunotherapeutic approach for the treatment of pancreatic adenocarcinoma by combining tumor-specific CAR-T cells with tumour-persistent immunostimulating bacteria.
Immunology
Final Report Abstract
This research aimed to extend CAR T cell therapy to the treatment of solid tumors, in par-ticular pancreatic cancer. This goal is to be achieved by developing a new combination therapy of CAR T cells and immunomodulating bacteria. As shown in our work, genetically modified bacteria persist in the tumor tissue and are eliminated by the endogenous immune system outside and in the border area of the tumor. For the activation of T cells, a novel technology should be used, which was developed in the same research group and perfected for the expression of recombinant proteins on the bacterial surface. For this purpose, the bacterial FimH is fused with a selected DNA sequence. To prove the principle, the DNA sequence was derived from the immune-activating cytokine TNF-α and fused with the FimH DNA sequence, expressed and its effect on immune and tumor cells exam-ined in vitro and in vivo. Unexpectedly, injection of such genetically engineered bacteria of the E. coli strain with inducible expression of the 2xTNF and 1xTNF constructs alone pro-longed the survival of mice with syngeneic and orthotopic pancreatic carcinomas and led to complete elimination of the tumors in some of the experimental animals without the addition of tumor-specific CAR-T cells. To explain this effect mechanistically, a series of in vitro experiments were performed. It turned out that the recombinant TNF-α leads to the activation of macrophages. However, it has not yet been possible to fully elucidate the antitumor effect in vitro experimentally, as the production of recombinant proteins in bacte-ria also releases LPS and endotoxins, which have an additional stimulating effect on the immune cells and can thus trigger considerable coactivation. However, there is evidence of a direct impact on immune cells by the recombinant proteins used, which have led to the development of tumor-specific T cells, making a combination treatment with CAR T cells obsolete. To improve the measurement of bioactivity and to avoid background activi-ty by interfering prokaryotic molecules, the recombinant TNF-α-FimH proteins are current-ly produced in eu-karyotic cells. This could prevent the possible impact of LPS, endotoxins and other interfering substances on the target cells. If the mechanism for prolonged sur-vival can be demonstrated, the next step is to transfer the constructs into the E. coli strain Nissle 1917 and to administer the bacteria orally instead of intraperitoneal injection.
Publications
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Regulatory CAR-T cells in autoimmune diseases: Progress and current challenges. Frontiers in Immunology, 13.
Riet, Tobias & Chmielewski, Markus
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An anti-CD19/CTLA-4 switch improves efficacy and selectivity of CAR T cells targeting CD80/86-upregulated DLBCL. Cell Reports Medicine, 5(2), 101421.
Prinz, Lars Fabian; Riet, Tobias; Neureuther, Daniel Felix; Lennartz, Simon; Chrobok, Danuta; Hübbe, Hanna; Uhl, Gregor; Riet, Nicole; Hofmann, Petra; Hösel, Marianna; Simon, Adrian Georg; Tetenborg, Luis; Segbers, Paul; Shimono, Joji; Gödel, Philipp; Balke-Want, Hyatt; Flümann, Ruth; Knittel, Gero; Reinhardt, Hans Christian ... & Chmielewski, Markus Martin
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Bridge over troubled cells: bone marrow stromal cells transfer mitochondria to boost T cells. Signal Transduction and Targeted Therapy, 9(1).
Prinz, Lars Fabian; Ullrich, Roland Tillmann & Chmielewski, Markus Martin
