Biology subjects

Droste, M.

Publications and source records attributed to Droste, M..

3 recordsLinked to original sources

bioRxiv2026

Engineering Functional CLA-Targeting CAR Approaches for Pancreatic Ductal Adenocarcinoma

Pancreatic cancer remains a highly lethal malignancy with limited therapeutic options. Chimeric antigen receptor (CAR) therapy has revolutionized the treatment of hematological cancers but still faces major limitations in solid tumors, particularly due to the scarcity of tumor-specific targets. Cutaneous lymphocyte antigen (CLA) recently emerged as a promising PDAC target due to its high tumor expression and limited presence in healthy tissues. However, previously reported CLA-directed CAR constructs lacked antitumor functionality. Here, we investigated multiple strategies to generate functional CLA-targeting CAR approaches. We first hypothesized that impaired activity resulted from fratricide caused by CLA expression on activated T cells. CLA knockout was successfully achieved through deletion of fucosyltransferase-7, but not by knockout of the major CLA carrier backbones CD162, CD44 or CD43, suggesting additional CLA carriers or compensatory regulation. As CLA knockout alone did not restore CAR-mediated killing, we explored whether insufficient binding affinity limited CAR activity. Affinity maturation was performed in silico and in vitro using yeast surface display, identifying 39 candidate mutations, although none restored cytotoxicity. We finally switched to an AdCAR strategy using anti-biotin CAR T cells combined with biotinylated anti-CLA scFv-Fc adapters. This approach enabled efficient, concentration-dependent cytotoxicity with both CLA-targeting binders. Additionally, we identified a dynamic, cell density-dependent regulation of CLA expression. Finally, glycan profiling of CLA binders further revealed broader-than-expected glycan interactions, suggesting a potentially wider definition of the CLA family. Overall, our findings establish CLA as a functional PDAC immunotherapy target while revealing unexpected complexity in its regulation and molecular presentation.

immunology↗

bioRxiv2025

On the conditions for shifts in metabolic strategies

AO_SCPLOWBSTRACTC_SCPLOWMany heterotrophic microorganisms gradually replace an energetically-efficient mode of metabolism by an inefficient, more-wasteful overflow metabolism above a critical growth rate, even though the energy demand continues to rise with growth rate. For instance, complete respiration of a sugar is replaced by its fermentation. We derive the conditions for this to happen, using a core model of metabolism and growth that is qualitatively in agreement with experimental data. Assuming a fixed cellular protein content, the model shows that protein expression of efficient metabolism and anabolism rises as function of growth rate until a critical value is reached. This growth-associated protein expression is at the expense of proteins associated with future adaptation. At the critical growth rate, this preparatory pool is reduced to zero. Beyond the critical growth rate, the anabolic protein pool and the energy demand continue to rise and therefore less protein remains for catabolism. In this regime, the inefficient metabolism gradually takes over ATP synthesis from the efficient mode. It can do so if it requires less protein per unit of ATP flux. The catabolic protein pool then decreases while the anabolic pool increases. This continues until all catabolic protein is allocated to the inefficient strategy and to anabolism. We show that this can occur only if the maximal growth rate of the inefficient mode is higher than the critical growth rate. We show that this condition is precisely the requirement for the second mode to be more proteome-efficient than the first mode. Finally, we reduce a genome-scale model of protein expression in the yeast Saccharomyces cerevisiae to a variant of our core model and show that it is still qualitatively in agreement with the experimental data used to validate the original model.

systems biology↗

bioRxiv2021

Single extracellular vesicle analysis performed by imaging flow cytometry in contrast to NTA rigorously assesses the accuracy of urinary extracellular vesicle preparation techniques

Extracellular vesicles (EVs) from several body fluids, including urine, appear as promising biomarkers. Within the last decade, numerous groups have compared the efficacy of EV preparation protocols. Frequently, the efficacy of EV preparation methods is judged by the recovery of particles as estimated by conventional nanoparticle tracking analysis (NTA) or other particle quantification devices. Here, at the example of different urinary EV (uEV) preparation methods, we determined the particle yield in obtained samples with conventional NTA, analyzed their EV content by imaging flow cytometry (IFCM) and quantified the intensity of TSG101 and the contaminant protein uromodulin (UMOD) in Western blots. Our results demonstrate a correlation among CD9-positive objects detected by IFCM and TSG101 Western blot intensities, while particle numbers as determined by NTA correlated with the amount of UMOD. Consequently, our results question the reliability of conventional NTA analyses for identifying the optimal EV preparation method. Here, in our method comparison, a combination of size exclusion chromatography followed by ultra-filtration showed the highest CD9-positive object and TSG101 protein recovery, and in relation to the number of CD9-positive objects, the lowest amount of UMOD contamination.

cell biology↗