Biology subjects

Rauwolf, K. K.

Publications and source records attributed to Rauwolf, K. K..

3 recordsLinked to original sources

bioRxiv2025

Phospho 394Y LCK flow-cytometry readout predicts dasatinib sensitivity in paediatric T-cell acute lymphoblastic leukaemia

Children with T-cell acute lymphoblastic leukaemia (T-ALL) who relapse or fail induction have poor outcomes. A subset of cases shows glucocorticoid resistance reversible by dasatinib through inhibition of LCK-dependent signalling. To identify a practical biomarker of dasatinib response, we compared in-vitro drug sensitivity with basal phosphorylation of pre-TCR pathway proteins in 28 paediatric T-ALL patient-derived xenografts (PDX). Phospho-flow cytometry quantified LCK (pY394), ZAP70 (pY319) and CD3{zeta} (pY142), normalised to internal controls. Dasatinib IC50 values correlated significantly with pLCK and pZAP70, with pLCK providing the best single-marker performance across clinically relevant thresholds. Logistic, ROC and precision-recall analyses confirmed that pLCK alone achieved excellent classification (AUC [≥] 0.9), while multivariate models added minimal predictive value. Model selection using LASSO and Bayesian Information Criterion further supported pLCK as the dominant predictor. These findings establish pLCK as a robust, scalable biomarker of dasatinib sensitivity suitable for diagnostic integration. A multicentre international validation programme is underway to harmonise pLCK assay protocols, expand testing across biobanks, and assess clinical feasibility in newly diagnosed and relapsed patients within the ALLTogether and HEM-iSMART trials respectively.

cancer biology↗

bioRxiv2024

Role of Stem-Like Cells in Chemotherapy Resistance and Relapse in pediatric T Cell Acute Lymphoblastic Leukemia

T cell acute lymphoblastic leukemia (T-ALL) is an aggressive leukemia predominantly affecting adolescents and young adults. T-ALL relapses are characterized by chemotherapy resistance, cellular heterogeneity and dismal outcome. To gain a deeper understanding of the cellular heterogeneity and mechanisms driving relapse, we conducted single-cell full-length RNA sequencing of 13 matched pediatric T-ALL patient-derived xenografts (PDX) samples obtained at initial diagnosis and relapse, generating the to date most comprehensive longitudinal single cell study in paired T-ALL samples, along with 5 non-relapsing PDX samples collected at initial diagnosis. This dataset identifies considerable transcriptomic diversity among individual T-ALL cell populations. Notably however, 11 of the 18 patients exhibit a small T-ALL cell subpopulation with a shared set of gene regulatory networks characterized by a common set of active regulons, expression patterns and splice isoforms. This profile involves the upregulation of a stem-like cell signature with enrichment of cell adhesion, and inhibition of the cell cycle and metabolic activity. Comprehensive investigations of these networks identify transcripts enforcing drug resistance through NF-{kappa}B expression and TGF-{beta} signaling and of anti-apoptotic T cell signaling. Longitudinal monitoring of these stem-like cells demonstrates this subpopulation to account for only a small proportion of leukemia cells initially with a substantial expansion at relapse suggesting resistance to first line therapy. Chemotherapy resistance is functionally corroborated through in vitro and in vivo drug testing. We thus report the discovery of inherently treatment-resistant stem-like T-ALL cell populations underscoring the potential for devising future therapeutic strategies aimed at targeting stemness pathways in pediatric T-ALL. Key PointsO_LISingle-cell full-length RNA sequencing reveals dormant, treatment-resistant cells expanding upon T cell acute lymphoblastic leukemia relapse. C_LIO_LIStem-like T-ALL cells exhibit a shared gene regulatory network conferring chemotherapy resistance and relapse. C_LI

cancer biology↗

bioRxiv2022

Collagen-binding integrin alpha11beta1 contributes to joint destruction in arthritic hTNFtg mice

BackgroundIn rheumatoid arthritis (RA), fibroblast like synoviocytes (FLS) undergo a "tumor-like" transformation, wherein they develop an aggressive phenotype that is characterized by increased adhesion to components of cartilage extracellular matrix (ECM) and that contributes extensively to joint destruction. The collagen binding integrin 11{beta}1 was previously shown to be involved in similar processes in cancer-associated fibroblasts mediating tumorigenicity and metastasis in certain tumors. Therefore, this study aimed to study the role of integrin 11{beta}1 in RA and to characterize the effects of 11{beta}1 deficiency on the disease course and severity in arthritic hTNFtg mice. MethodsThe expression levels of integrin 11{beta}1 were analyzed by immunohistochemistry, immunofluorescence, and western blot analysis in synovial samples and FLS of patients with RA and osteoarthritis (OA) as well as in samples from wild type (wt) and arthritic hTNFtg mice. Furthermore, the subcellular expression of integrin 11{beta}1 was investigated in co-culture experiments with cartilage explants and analyzed by transmission electron microscopy. To investigate the effects of integrin 11{beta}1 deficiency, itga11-/- mice were interbred with hTNFtg mice and disease severity was assessed by clinical scoring of grip strength and paw swelling over the disease course. Hind paws of 12-weeks-old mice of all genotypes were analyzed by {micro}CT imaging followed by stainings of paraffin-embedded tissue sections with Toluidine-blue and tartrate-resistant acid phosphatase (TRAP) to evaluate established parameters of joint destruction such as inflammation area, cartilage destaining, FLS attachment to the cartilage surface, and bone damage. ResultsExpression levels of integrin 11{beta}1 were clearly elevated in synovial tissues and FLS from RA patients and hTNFtg mice, compared to the controls derived from OA patients and wt mice. Interestingly, this expression was shown to be particularly localized in focal adhesions of the FLS. As revealed by transmission electron microscopy, integrin 11{beta}1 expression was particularly evident in areas of direct cellular contact with the ECM of cartilage. Evaluations of clinical scorings and histomorphological analyses demonstrated that itga11-/-hTNFtg displayed alleviated clinical symptoms, higher bone volume, less cartilage destruction and reduced FLS attachment to the cartilage in comparison to hTNFtg mice. ConclusionsThe collagen-binding integrin 11{beta}1 is upregulated in the context of RA and its deficiency in mice with an inflammatory hTNFtg background leads to a significant reduction in the arthritic phenotype which makes integrin 11{beta}1 an interesting target for therapeutical intervention.

molecular biology↗