Biology subjects

Hudecek, M.

Publications and source records attributed to Hudecek, M..

15 recordsLinked to original sources

bioRxiv2026

Profound CD4+ T-Cell Reprogramming by Melphalan-Driven Oxidative Stress in High-Risk Multiple Myeloma

T cell-based immunotherapies have become central to the treatment of multiple myeloma (MM), yet their efficacy depends on the functionality of endogenous T cells. How cumulative treatment exposure, particularly high-dose melphalan, together with disease-intrinsic high-risk features shapes T-cell composition and immune competence remains incompletely understood. Here, we analyzed T cell composition and function in bone marrow (BM) and peripheral blood (PB) samples from MM patients across different stages of their treatment journey using flow cytometry (BM, n=162; PB, n=1,733), single-cell RNA sequencing (n=19), and cytotoxicity assays (n=20). We reveal reduced overall T cell frequencies and CD4+/CD8+ T cell ratio, associated with lines of therapy and driven in part by depletion of naive CD4+ T cells in gene-expression defined high risk (HR) disease. Among therapeutic agents, melphalan exerted the strongest effects on T cell populations and induced pronounced redox stress in both T cells and myeloma cell lines. This oxidative stress signature was enriched in HR patients and was reversible with N-acetyl-L-cysteine treatment. Together, these findings identify immune dysregulation as a defining feature of HR MM that extends beyond tumor-intrinsic genomic alterations and is further shaped by treatment-induced remodeling of the BM microenvironment. Given the association between higher CD4+ T cell numbers and improved CAR-T cell outcomes, our data highlight the translational importance of treatment sequencing, particularly in HR MM. One Sentence SummaryMelphalan-induced redox stress depletes CD4+ naive T cells, particularly in patients with high-risk multiple myeloma.

Cancer Biology↗

bioRxiv2026

A tonoplast cytokinin riboside transporter gates intracellular hormone availability at the plant-microbe interface

Cytokinin ribosides are major mobile and precursor forms of cytokinins, plant hormones whose transport and subcellular distribution shape developmental and stress responses. Here, we identify Arabidopsis thaliana EQUILIBRATIVE NUCLEOSIDE TRANSPORTER1 (ENT1) as a tonoplast-localized cytokinin riboside transporter. Tissue-specific subcellular analysis under native regulatory elements localized ENT1 predominantly to the tonoplast of root epidermal and lateral root cap cells, where it gates intracellular cytokinin riboside availability. Accordingly, ENT1 overexpression enhanced cytokinin riboside sensitivity and signalling, whereas loss of ENT1 altered adenosine metabolism and disrupted cytokinin homeostasis, leading to the accumulation of multiple zeatin-type cytokinins. ENT1-dependent cytokinin riboside compartmentalization was required for beneficial microbe-induced protection, as ent1 mutants failed to acquire protection against the fungal pathogen Botrytis cinerea and the bacterial pathogen Pseudomonas syringae pv. tomato DC3000. These findings reveal a vacuolar gatekeeping mechanism that controls intracellular cytokinin riboside availability and links hormone compartmentalization to beneficial microbe-dependent plant defence.

plant biology↗

bioRxiv2025

TCR activation impairs CAR-T cytotoxicity against separate target cells

Chimeric antigen receptor T cells (CAR-T) are effective therapeutics against cancer and autoimmunity, but whether the endogenous T-cell receptor (TCR) is beneficial, detrimental or irrelevant for CAR-T function and patient outcome remains unclear. We here traced anti-CD19 CAR-T clonotypes in patients with B-cell malignancies pre- and post-infusion using single-cell RNA-, TCR-, and CITE-sequencing. A cytotoxic phenotype, but not CAR-mediated in vitro reactivity to tumor cells, predicted CAR-T persistence. To test the functional impact of endogenous TCR activity on CAR-T behavior, we combined CAR transduction with orthotopic TCR replacement. This revealed that TCR signaling adds to activation of CAR-T cells, but gradually compromises CAR-mediated cytotoxicity, when TCR and CAR antigens are presented by different target cells. Therefore, spatial antigen separation alters TCR/CAR interplay with implications for therapeutic CAR-T design.

immunology↗

bioRxiv2025

A novel CAR T cell blend targeting PDPN and GD2 to overcome glioblastoma heterogeneity

BackgroundWhile chimeric antigen receptor (CAR) T cells have achieved encouraging remission rates in hematological malignancies, they demonstrated limited success in treating Glioblastoma (GBM), particularly due to high intra- and intertumoral heterogeneity. In this study, we identified a relevant and preserved target antigen, Podoplanin (PDPN), and evaluated the potential of a PDPN- and GD2-CAR T cell blend to overcome GBM heterogeneity. MethodsTarget antigen screening included clinical samples, healthy tissues and cell lines, as well as publicly available RNA sequencing datasets. The anti-tumor function of CAR T cells were examined in co-culture experiments with GBM cell lines and patient-derived organoids (PDOs), and in vivo after locoregional delivery in orthotopic xenograft models. ResultsThe generated CAR T cells demonstrated strong anti-tumor activity against several cell lines and PDOs from multiple patients. PDPN and GD2 expression was detectable in all PDOs at varying densities and regardless of the antigenic profile, the CAR T cell blend induced significantly higher levels of apoptosis in organoids than single antigen targeting counterparts. In vivo, we observed efficient tumor regression after locoregional administration of monospecific CAR T cells. While heterogeneous orthotopic tumors eventually relapsed in these groups, blended therapy resulted in a significantly increased overall survival and even achieved cure in the majority of mice. ConclusionThis novel PDPN-/GD2-CAR T cell blend demonstrated strong efficacy in advanced preclinical models of glioblastoma. The results suggest that this approach can overcome GBM heterogeneity in clinical application and address previous limitations of single antigen CAR T cell therapies. KEYPOINTSO_LIPDPN is a relevant and consistent CAR T cell target antigen in primary and recurrent GBM C_LIO_LIPDPN- and GD2-CAR T cells display synergistic anti-tumor activity in patient-derived organoids C_LIO_LILocal delivery of our CAR T cell blend confers long-term survival and cure in GBM-bearing mice C_LI IMPORTANCE OF THE STUDYThe highly variable landscape of tumor antigens in GBM represents a serious obstacle to single antigen CAR T cell therapies. In this study, we identified Podoplanin (PDPN) and GD2 as the most preserved target antigens in a screening campaign, with an even increased density in recurrent GBM compared to primary GBM. We combined PDPN- and GD2-CAR T cells in a blended treatment approach to counter antigen heterogeneity, and achieved a substantial gain in efficacy against patient-derived organoids (PDOs). In an orthotopic xenograft model, locoregional administration of the PDPN- and GD2-CAR T cell blend conferred long-term complete remission and increased survival compared to single antigen targeting. This study provides a hierarchy of CAR target antigens for treating GBM and illustrates the therapeutic potential of combinatorial antigen targeting using a PDPN/GD2-CAR T cell blend. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=89 SRC="FIGDIR/small/636223v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@109a9aaorg.highwire.dtl.DTLVardef@16215faorg.highwire.dtl.DTLVardef@910623org.highwire.dtl.DTLVardef@129f79c_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGRAPHICAL ABSTRACT:C_FLOATNO C_FIG

immunology↗

bioRxiv2025

Autocrine glucocorticoid signaling in hormonally active cancer induces antigen expression for immunotherapy

Exogenous glucocorticoids (GCs) suppress T cell-based immunotherapy, yet the consequences of endogenous GCs produced or regenerated by tumours remain poorly understood. Here, we show that tumour-derived GCs couple immune evasion to therapeutic antigenicity. In adrenocortical carcinoma, autonomous GC production activates hGR-STAT3 signaling to increase the surface antigen ROR1. This creates an immunological paradox in which GC excess promotes therapeutic antigen expression while suppressing T cell-mediated antitumor activity. Selective hGR-knockout renders ROR1 CAR-T cells GC-resistant while preserving GC-driven ROR1 expression in tumor cells, resulting in durable tumor control in vivo. Non-endocrine pancreatic and triple-negative breast cancers recreate this circuit through HSD11B1-mediated GC recycling, which is further induced by CAR-T cell-derived cytokines under immune pressure. Thus, GC-resistant CAR-T cells exploit a tumor-derived endocrine program that couples immune suppression to therapeutic antigenicity.

cancer biology↗

bioRxiv2024

Microbial metabolite-guided CAR T cell engineering enhances anti-tumor immunity via epigenetic-metabolic crosstalk

The microbiome is a complex host factor and key determinant of the outcome of antibody-based and cellular immunotherapy. Its postbiotics are a blend of soluble commensal byproducts that are released into the host environment and have been associated with the regulation of immune homeostasis, particularly through impacts on epigenetics and cell signaling. In this study, we show that the postbiotic pentanoate is metabolized to citrate within the TCA cycle via both the acetyl- and succinyl-CoA entry points, a feature uniquely enabled by the chemical structure of the C5 aliphatic chain. We identified ATP-citrate lyase as the crucial factor that redirects pentanoate-derived citrate from the succinyl-CoA route to the nucleus, thereby linking metabolic output and histone acetylation. This epigenetic-metabolic crosstalk mitigated T cell exhaustion and promoted naive-like differentiation in pentanoate-programmed chimeric antigen receptor (CAR) T cells. The predictive and therapeutic potential of pentanoate was corroborated in two independent patient cohorts and three syngeneic models of CAR T adoptive therapy. Our data demonstrate that postbiotics are integrated into mitochondrial metabolism and subsequently incorporated as epigenetic imprints. This bridge between microbial and mammalian interspecies communication can ultimately impact T cell differentiation and efficacy.

immunology↗

bioRxiv2024

Comprehensive Model of Cell-to-Cell Cytokinin Transport Reveals A Specific Mode of Cytokinin Riboside Influx

1Ribosylated forms of plant hormones cytokinins (CKs) are the dominant CK species translocated at long distances. Their particular roles in plant physiology imply the existence of a yet uncharacterized CK riboside-specific membrane transport system. In this work, we report significant differences in the kinetics of the membrane transport of CK nucleobases and ribosides and the overall affinity of membrane-bound carriers towards the two CK forms. We show that CK ribosides can inhibit the uptake of CK nucleobases in tobacco Bright Yellow 2 cell suspensions but not vice versa, confirming the existence of a membrane transport system that strictly recognizes CK ribosides. We further characterize the membrane transport of CK nucleobases and ribosides mediated by AtENT3 (EQULIBRATIVE NUCLEOSIDE TRANSPORTER 3), showing its preference towards trans-zeatin riboside (tZR) over isopentenyl adenosine (iPR). With the molecular docking and molecular dynamics, we assess the interactions among the side chain of tZR and AtENT3 residues Tyr61 and Asp129, which are conserved in all AtENTs but not in the ENTs from non-plant species. Lastly, we show that atent3 mutation affects shoot phenotype, demonstrating the impact of CK riboside membrane transport on shoot development.

plant biology↗

bioRxiv2023

Mutation-specific CAR T cells as precision therapy for IGLV3-21R110 expressing high-risk chronic lymphocytic leukemia

The concept of precision cell therapy targeting tumor-specific mutations is appealing but requires surface-exposed neoepitopes, which is a rarity in cancer. B cell receptors (BCR) of mature lymphoid malignancies are exceptional in that they harbor tumor-specific-stereotyped sequences in the form of point mutations that drive self-engagement of the BCR and autologous signaling. Here, we used a BCR light chain neoepitope defined by a characteristic point mutation (IGLV3-21R110) for selective targeting of a poor-risk subset of chronic lymphocytic leukemia (CLL) with chimeric antigen receptor (CAR) T cells. We developed murine and humanized CAR constructs expressed in T cells from healthy donors and CLL patients that eradicated IGLV3-21R110 expressing cell lines and primary CLL cells, but not polyclonal healthy B cells. In vivo experiments confirmed epitope-selective cytolysis in xenograft models using engrafted IGLV3-21R110 expressing cell lines or primary CLL cells. We further demonstrate in two humanized mouse models lack of cytotoxicity towards human B cells. These data provide the basis for novel avenues of resistance-preventive and biomarker-guided cellular targeting of functionally relevant lymphoma driver mutations sparing normal B cells.

cancer biology↗

bioRxiv2023

Depletion of alloreactive B cells by chimeric alloantigen receptor T cells with drug resistance to prevent antibody-mediated rejection in solid organ transplantation

In the present study, we developed a novel cell therapy approach to selectively combat antibody-mediated rejection (AMR), a major and unresolved complication after solid organ transplantation (SOT) caused by donor-HLA-specific, alloreactive B cells. Current treatment options including B-cell depletion protocols are inefficient and result in complete loss of humoral immunity. To selectively eliminate alloreactive B cells characterized by corresponding anti-donor-HLA B-cell receptors (BCRs), we engineered T cells with a novel chimeric receptor comprising a truncated HLA molecule fused to intracellular 4-1BB/CD3{xi} signaling domains to generate T cells overcoming rejection by antibodies (CORA-Ts). As proof-of-concept, CORA receptors based on HLA-A*02 were shown to bind anti-HLA-A*02 antibodies from the serum of kidney transplant recipients, indicating their suitability to also target the respective membrane-bound anti-HLA-A*02 BCRs on alloreactive B cells. In co-cultures with B-cell lines expressing and releasing anti-HLA-A*02 antibodies, CORA-Ts were specifically activated, released pro-inflammatory cytokines (e.g. IFN-{gamma}, granzyme B), and exhibited strong cytotoxicity resulting in an effective reduction of anti-HLA-A*02 antibody release. A modification of the HLA-A*02 3-domain within the CORA receptor effectively abrogated T-cell sensitization. Additionally, using CRISPR/Cas9-mediated knockout of a selected binding protein, CORA-Ts were able to resist immunosuppressive treatment to ensure high efficiency in transplant patients. Our results demonstrate that CORA-Ts are able to specifically recognize and eliminate alloreactive B cells, and thus selectively prevent formation of anti-HLA antibodies even under immunosuppressive conditions. This suggests CORA-Ts as potent novel approach to specifically combat AMR and improve long-term graft survival in SOT patients while preserving their overall B-cell immunity.

immunology↗

bioRxiv2023

CARs are organized in nanodomains in the plasma membrane of T cells that accumulate at tumor contact sites

Chimeric antigen receptors (CARs) are synthetic immune receptors that are expressed in T cells through genetic engineering. CAR-T cells have been successfully used to eradicate very advanced leukemias and lymphomas and their functional properties have been intensively studied. However, relatively little is known about the spatiotemporal expression and organization of CARs on the T-cell membrane and how this influences their efficacy. Here, we applied super-resolution microscopy to visualize CD19-, ROR1-, and ROR2-specific CARs in human CD4+ and CD8+ T cells that were engineered with lentiviral and transposon-mediated gene transfer. Our data show that the majority of CARs is organized in nanodomains virtually independent of the T cell type, CAR construct and expression level. Quantitative analyses revealed a slightly higher CAR density in transposon-engineered T cells correlating with higher antigen sensitivity and faster resolution of anti-tumor functions compared to lentivirally-engineered T cells. Live-cell fluorescence imaging revealed that both, CAR nanodomains and CAR monomers accumulate at tumor contact sites and form multifocal immunological synapses. Our study provides novel insights into the membrane organization of CARs with single-molecule resolution and illustrates the potential of advanced microscopy to inform the rational design of synthetic immune receptors for applications in immune cell therapy.

immunology↗

bioRxiv2023

Solid tumor-on-chip model for efficacy and safety assessment of CAR-T cell therapy

The non-clinical assessment of CAR-T cells demands innovative models that are capable of predicting safety and efficacy in the clinical setting. Here, we present a novel solid tumor-on-chip model that allows CAR-T cell perfusion and integrates the vasculature and tumor lesions to recapitulate key events of CAR-T cell performance including extravasation, tumor infiltration and cytokine release. We assessed CAR-T cells targeting the ROR1 antigen against tumor aggregates that were derived from a breast cancer cell line and primary breast cancer organoids. The data show the temporal kinetic of ROR1 CAR-T cell migration and expansion, lytic activity and cytokine production over the course of 8 days, and reveal a correlation between anti-tumor efficacy and ROR1 antigen density on tumor cells. CAR-modified T cells extravasated faster, infiltrated tumor lesions stronger, persisted longer and in higher numbers than non-CAR modified T cells. Intriguingly, we detected cytokine release levels and kinetics typically observed in patients who developed cytokine release syndrome, and administered dasatinib as a pharmacologic OFF switch to control this inflammatory response. The data illustrate the ability of this tumor-on-chip platform to assess parameters associated withherapeutic outcome and the potential to aid in patient stratification and monitoring of CAR-T cell therapy.

bioengineering↗

bioRxiv2023

TCR/CD3-based synthetic antigen receptors (TCC) convey superior antigen sensitivity combined with high fidelity of activation

Low antigen sensitivity and a gradual loss of effector functions limit the clinical applicability of chimeric antigen receptor (CAR)-modified T-cells and call for alternative antigen receptor designs for effective T-cell-based cancer immunotherapy. Here we applied advanced microscopy to demonstrate that TCR/CD3-based synthetic constructs (TCC) outperform second-generation CAR formats with regard to conveyed antigen sensitivities by up to a thousand-fold. TCC-based antigen recognition occurred without adverse non-specific signaling, which is typically observed in CAR-T-cells, and did not depend - unlike sensitized peptide/MHC detection by conventional T-cells - on CD4- or CD8- coreceptor engagement. TCC-endowed signaling properties may prove critical when targeting antigens in low abundance and aiming for a durable anti-cancer response.

immunology↗

bioRxiv2023

HTLV-1 Splice Sites in Prevalent Gene VectorsCause Splicing Perturbations in Transgenic Human Cells

The use of any semi-randomly integrating gene vector in a therapeutic setting is associated with genotoxic risks. The two major mechanisms of genotoxicity are disruption of a coding sequence (loss-of-function) or transcriptional upregulation of genes (gain-of-function) in the cellular genome where the genetic modifications are executed. A third, less widely recognized genotoxic risk stems from splice sites and polyadenylation sites within the vector sequences. These transcriptional elements may drive aberrant splicing and/or polyadenylation between transgene-contained and genomic sequences. A widely used promoter/enhance element present in gene vectors to ensure high transgene expression levels in mammalian cells is composed of a hybrid EF1/HTLV-1 LTR, in which the retroviral LTR contains an intron. We assessed aberrant splicing initiated from the splice donor (SD) element present in the HTLV-1 LTR in CAR-T cells that had been engineered by either lentiviral vector (LV) or Sleeping Beauty (SB) transposon-mediated gene transfer. We establish that the vector-contained canonical SD site gives rise to aberrantly spliced RNA species and thereby can cause misexpression of host gene segments that are involved in various host cell functions. This, potentially genotoxic, effect could be abrogated by mutating or completely eliminating the SD (or the entire intron) from the HTLV-1 LTR segment. CAR-T cells generated by the modified vectors are equally potent in efficiency of CAR-T cell manufacturing and in functionality. The simple genetic modifications that we describe here affecting vector design therefore enhance genomic safety while maintaining efficacy of gene-modified therapeutic cells.

genomics↗

bioRxiv2019

Inefficient ZAP70-Signaling Blunts Antigen Detection by CAR-T-Cells

Rational design of chimeric antigen receptors (CARs) with optimized anti-cancer performance mandates detailed knowledge of how CARs engage tumor antigens and how antigen-engagement triggers activation. We analyzed CAR-mediated antigen recognition via quantitative single molecule live-cell imaging and found the sensitivity of CAR-T-cells towards antigen approximately 1000-times reduced when compared to T-cell antigen receptor (TCR)-mediated recognition of nominal peptide/MHC complexes. While CARs outperformed TCRs with regard to antigen binding within the immunological synapse, proximal signaling was significantly attenuated due to inefficient recruitment of the tyrosine-kinase ZAP70 to ligated CARs and its reduced concomitant activation and subsequent release. Our study exposes signaling deficiencies of state-of-the-art CAR-designs, which limit at present the efficacy of CAR-T-cell therapies to target tumors with diminished antigen expression.

immunology↗

bioRxiv2019

Genomic Analyses of SLAMF7 CAR-T Cells Manufactured by Sleeping Beauty Transposon Gene Transfer for Immunotherapy of Multiple Myeloma

Widespread treatment of human diseases with gene therapies necessitates the development of gene transfer vectors that integrate genetic information effectively, safely and economically. Accordingly, significant efforts have been devoted to engineer novel tools that i) achieve high-level stable gene transfer at low toxicity to the host cell; ii) induce low levels of genotoxicity and possess a safe integration profile with a high proportion of integrations into safe genomic locations; and iii) are associated with acceptable cost per treatment and scalable/exportable vector production to serve large numbers of patients. The Sleeping Beauty (SB) transposon has been transformed into a vector system that is fulfilling these requirements.\n\nIn the CARAMBA project, we use SB transposition to genetically modify T cells with a chimeric antigen receptor (CAR) specific for the SLAMF7 antigen, that is uniformly and highly expressed on malignant plasma cells in multiple myeloma. We have demonstrated that SLAMF7 CAR-T cells confer specific and very potent anti-myeloma reactivity in pre-clinical models, and are therefore preparing a Phase I/IIa clinical trial of adoptive immunotherapy with autologous, patient-derived SLAMF7-CAR T cells in multiple myeloma (EudraCT Nr. 2019-001264-30/CARAMBA-1).\n\nHere we report on the characterization of genomic safety attributes in SLAMF7 CAR-T cells that we prepared in three clinical-grade manufacturing campaigns under good manufacturing practice (GMP), using T cells that we obtained from three healthy donor volunteers. In the SLAMF7 CAR-T cell product, we determined the average transposon copy number, the genomic insertion profile, and presence of residual SB100X transposase. The data show that the SLAMF7 CAR transposon had been inserted into the T cell genome with the close-to-random distribution pattern that is typical for SB, and with an average transposon copy number ranging between 6 and 12 per T cell. No residual SB100X transposase could be detected by Western blotting in the infusion products. With these attributes, the SLAMF7 CAR-T products satisfy criteria set forth by competent regulatory authorities in order to justify administration of SLAMF7 CAR-T cells to humans in the context of a clinical trial. These data set the stage for the CARAMBA clinical trial, that will be the first in the European Union to use virus-free SB transposition for CAR-T engineering.\n\nDisclosuresThis project is receiving funding from the European Unions Horizon 2020 research and innovation programme under grant agreement No 754658 (CARAMBA).

bioengineering↗