Biology subjects

Basiarz, E.

Publications and source records attributed to Basiarz, E..

4 recordsLinked to original sources

bioRxiv2026

Epithelial Stem Cell Fate Determines Chemoradiotherapy Response in Rectal Cancer

Rectal cancers are often treated with neoadjuvant chemoradiotherapy (CRT), yet 85% of patients do not achieve a pathological complete response. To identify the molecular determinants of CRT response, we profiled the single-cell signalling, DNA-damage, cell-cycle, apoptotic, and cell-fate responses of 2,769 patient-derived organoid cultures treated with CRT, cancer-associated fibroblasts (CAFs), and signal-rewiring agents. We find that CRT response is determined by stem cell-fate. CRT triggers comparable DNA-damage in isogenic proliferative (proCSC) and revival (revCSC) colonic stem cells, but proCSC retain damage and die whereas revCSC resolve damage and persist. Both CRT and CAFs drive proCSC to a common treatment-resistant revCSC fate and high revCSC predicts worse survival in patients. Pharmacologically constraining stem-cell plasticity increases CRT sensitivity, and Spatial Perturbation of ARrayed Tumour Assembloids (SPARTA) confirms YAP/TEAD inhibition improves chemotherapy responses in human stromal-tumour models. These results suggest that cancer cell-fate, not genotoxic damage itself, ultimately governs response to standard-of-care chemoradiotherapy. HIGHLIGHTSO_LIRectal cancer stem cell-fate determines chemoradiotherapy-induced apoptosis C_LIO_LIproCSCs retain DNA-damage and die, whereas revCSCs repair damage and persist C_LIO_LICAFs and chemoradiotherapy converge on a common chemo-radioresistant revCSC state C_LIO_LISPARTA reveals TEAD inhibition blocks DNA-repair persisters in stromal assembloids C_LI

cancer biology↗

bioRxiv2026

Signalome-wide mapping of the NFκB pathway in T-cells reveals novel targets for immunotherapy

Cell signalling networks govern fundamental cellular processes yet remain incompletely defined. Moreover, what is known is biased toward a limited subset of well-characterised components. Phosphoprotein-based interrogation methods, including mass spectrometry and targeted phosphosite panels, have limited utility in physiological settings dependent on cell-cell interactions because the signalling fluxes can be difficult to detect despite producing robust functional responses. Here we developed a perturbation-based experimental framework that infers signalling pathway architecture using quantitative functional outputs rather than direct measurements of effector state, e.g., phosphorylation levels. Using antigen-specific, NF-{kappa}B-GFP reporter-expressing transformed T-cells co-cultured with cellular targets, we performed an arrayed CRISPR-Cas9 screen targeting a curated signalome of kinases, phosphatases, adaptor and scaffolding proteins, totalling 706 genes. Quantitative effect-size profiling recovered canonical T-cell receptor regulators and revealed unequal, family-specific patterns of control over NF-{kappa}B activation. Comparing T-cell stimulation with low- and high-affinity antigen uncovered signal-strength-dependent buffering of proximal signalling nodes, exemplified by reduced sensitivity to perturbation of LCK under high-intensity stimulation. Targeted perturbation in primary human CD8 T-cells validated our findings and identified TRRAP and CTDSPL2 as negative regulators of T-cell effector output, whose disruption enhanced cytotoxicity, degranulation, and cytokine production in both polyclonal and TCR-engineered T cells. Together, these results establish a scalable strategy for mapping signalling pathway architecture in the setting of physiological T-cell activation.

immunology↗

bioRxiv2025

T-cell signaling relies on partial CD45-exclusion at sub-micron sized cellular contacts

How cell contact initiates T-cell activation is uncertain. The local exclusion of the receptor-type protein tyrosine phosphatase CD45 at cell contacts is believed to trigger immune receptor signaling but this is yet to be observed for T cells interacting with authentic cellular targets. Here, quantitative imaging of T cells interacting with tumor cells presenting either native or clinically relevant bi-specific TCR ligands, revealed that they form multiple sub-micron sized close contacts with their targets. The contacts were stabilised by the adhesion protein CD2, but efficient ligand detection required both CD2 and integrin ligation. CD45 was excluded from close contacts at the time of ZAP70 recruitment and signaling, but only partially (30- 40%). A single-cell, mass cytometric analysis showed that this change in kinase/phosphatase activity provoked strong T-cell activation and potent cytotoxicity via very small changes in signaling fluxes. Spatial stochastic simulations suggested that the proximal T-cell signaling network is optimised for efficient antigen discrimination in the setting of partial CD45 exclusion. Our work re-frames early T-cell activation as a process initiated by relatively subtle changes in kinase/phosphatase activity acting on small numbers of signaling effectors at minute cellular contacts.

immunology↗

bioRxiv2024

SIGNAL-seq: Multimodal Single-cell Inter- and Intra-cellular Signalling Analysis

We present SIGNAL-seq (Split-pool Indexing siG-Nalling AnaLysis by sequencing): a multiplexed splitpool combinatorial barcoding method that simultaneously measures RNA and post-translational modifications (PTMs) in fixed single cells from 3D models. SIGNAL-seq PTM measurements are equivalent to mass cytometry and RNA gene detection is analogous to split-pool barcoding scRNA-seq. By measuring both mRNA ligand-receptor pairs and PTMs in single cells, SIGNAL-seq can simultaneously uncover inter- and intra-cellular regulation of tumour microenvironment plasticity.

cancer biology↗