Biology subjects

Winschel, M.

Publications and source records attributed to Winschel, M..

3 recordsLinked to original sources

bioRxiv2025

PTPN2-KO CAR-T Cells Demonstrate Enhanced Effector Function, CNS Infiltration, and Toxicity in a Non-Human Primate CAR-T Model

B-cell targeting CAR-T cell therapies achieve high remission rates, yet durable responses occur in fewer than 40% of patients. Deletion of negative T-cell regulators, such as PTPN2, a key inhibitor of TCR and cytokine signaling, represents a promising strategy to enhance the efficacy of CAR-T cells. While transfer of PTPN2 knockout (KO) T cells has demonstrated antitumor benefits in murine models, its impact on human-derived CAR-T cells and, importantly, the associated in vivo efficacy and toxicity remain unclear. Here, we demonstrate that PTPN2-KO human CD19 CAR-T cells exhibit enhanced cytokine production, cytotoxicity, TCR and CAR affinity and signaling, leading to superior in vitro elimination of leukemic cells with low CD19 expression. To assess in vivo efficacy and toxicity, we performed a dose-escalation study using a non-human primate (NHP) model of B-cell-targeting CD20 CAR-T cell therapy. We demonstrated that PTPN2-KO CD20 CAR-T cells exhibited superior in vivo expansion and B-cell depletion compared to WT CAR-T cells, in a dose-dependent manner. At the highest dose level, CAR-T expansion was associated with increased toxicities, particularly ICANS, compared to PTPN2 WT CD20 CAR-T cells driven by enhanced CNS-infiltration. Transcriptional profiling revealed a dominant effector and proliferative signature, with cytotoxic CNS-infiltrating CD8+ PTPN2-KO CAR-T cells implicated in ICANS pathogenesis. This study details the comprehensive evaluation of PTPN2-KO CAR-T cells in an immunocompetent model, demonstrating their enhanced on-target functionality, while highlighting increased toxicity risks, underscoring the need for rigorous preclinical assessment of potent genetic modifications in CAR-T therapy. Key pointsO_LIPTPN2-KO CAR-T cells exhibit enhanced effector function C_LIO_LIIn a dose escalation study in rhesus macaques, PTPN2-KO mediated enhanced proliferation and CNS infiltration was associated with increased ICANS C_LI

immunology↗

bioRxiv2025

KAT6A/B inhibition synergizes with retinoic acid and enhances the efficacy of GD2-targeted immunotherapy in neuroblastoma

High-risk neuroblastoma accounts for about 15% of childhood cancer deaths and arises from precursors of the peripheral sympathetic nervous system. Retinoids are clinically used to inhibit growth of neuroblastoma cells through reconfiguration of the regulatory enhancer landscape. Its effects, however, are completely reversible after drug withdrawal, leading to rapid tumor cell proliferation. Here, we sought to identify epigenetic modifiers that potentiate the antiproliferative effects of retinoids in neuroblastoma. We identified PF-9363, an inhibitor of the histone H3K23 acetyltransferases KAT6A/B, as synergistically inhibiting neuroblastoma growth in combination with retinoids. PF-9363 plus retinoids induces durable growth arrest, which persists beyond retinoid withdrawal in vitro and in vivo with sustained Polycomb-mediated repression of oncogenic transcription factors MYCN, PHOX2B and GATA3. Moreover, PF-9363 plus retinoids increases GD2 expression, rendering neuroblastoma cells more sensitive to anti-GD2 immunotherapy. Overall, our studies demonstrate that KAT6A/B inhibition increases the effectiveness of retinoids and GD2-targeted immunotherapy in neuroblastoma.

cancer biology↗

bioRxiv2025

Precision Editing of Cyclophilin A Generates Cyclosporine and Voclosporin Resistant Cellular Therapies

Recipients of allogeneic transplants or patients with autoimmune disease require immune suppression, often with calcineurin inhibitors. There is an expanding repertoire of immune effector cell therapies, including CD19 CAR-T cells and viral-specific T cells, deployed in these patients; however, ongoing calcineurin inhibition may be detrimental to cell therapy function. We developed a CRISPR/Cas9-based approach to engineer dual cyclosporine/voclosporin resistant cell therapies by targeting PPIA (encoding cyclophilin A), a critical binding partner for both drugs. Because Cyclophilin A has homeostatic functions in T cells, a complete knock-out is detrimental to cell viability. We thus targeted its C-terminus, disrupting drug binding while leaving the majority of the protein intact. C-terminal editing was stable throughout expansion and preserved Cyclophilin A expression. Edited CD19 CAR-T cells retained effector function in the presence of cyclosporine and voclosporin, including proliferation, cytokine production, and target cell killing, resulting in improved survival in murine models of CD19+ leukemia. Edited CMV-specific T cells also demonstrated preserved antigen-specific proliferation and cytokine production in the presence of these drugs. C-terminal editing of Cyclophilin A offers a promising avenue for developing next-generation cell therapies for patients receiving calcineurin inhibitors.

immunology↗