Biology subjects

Gotthardt, D.

Publications and source records attributed to Gotthardt, D..

3 recordsLinked to original sources

bioRxiv2025

A STAT5B-driven mouse model of hepatosplenic γδ T-cell lymphoma reveals therapeutic efficacy of JAK inhibition

Hepatosplenic T-cell lymphoma (HSTCL) is a rare and aggressive neoplasm associated with poor responses to standard chemotherapy regimens and low survival rates. No targeted therapies are available for HSTCL, and preclinical models to test new treatment options have not been established. The JAK-STAT signaling cascade is a key dysregulated pathway in HSTCL, and STAT5BN642His the most frequent somatic mutation in the disease. Here, we report on newly established clonal, murine {gamma}{delta} T-cell lymphoma cell lines initiated and driven by oncogenic STAT5BN642H, which recapitulate key immunophenotypic features, gene expression profiles and typically low cytolytic activity of patient-derived human HSTCL cells. CRISPR-Cas9 mediated knockout demonstrated growth dependence on STAT5BN642H. Murine C15 cells were allo-engrafted intravenously into both immunodeficient and immunocompetent mice to model an aggressive HSTCL-like disease at high penetrance, with recipient mice displaying hepatosplenomegaly and destructive {gamma}{delta} T cell organ infiltration, including bone marrow and blood involvement. We identified the potential of JAK inhibition as a targeted treatment strategy for HSTCL, and found the clinically approved JAK inhibitor upadacitinib to display selective anti-tumor efficacy against STAT5B-mutated HSTCL cell lines in vitro, in vivo, and in primary HSTCL patient samples. Overall, we describe the first robust STAT5B-driven preclinical model resembling features of HSTCL in an immune competent setting. This tool is expected to accelerate the study of HSTCL disease mechanisms and the testing of novel therapies. Our data further present the JAK inhibitor upadacitinib as a promising targeted treatment option for STAT5B-mutated HSTCL.

cancer biology↗

bioRxiv2023

NK cells shape the clonal evolution of B-ALL cells by IFN-γ production

The term cancer immunoediting describes the dual role by which the immune system can suppress and promote tumour growth and is divided into three phases: elimination, equilibrium and escape. The role of NK cells has mainly been attributed to the elimination phase. Here we show that NK cells play a role in all three phases of cancer immunoediting. Extended co-culturing of DNA barcoded mouse BCR/ABLp185+ B acute lymphoblastic leukaemia (B-ALL) cells with NK cells allowed for a quantitative measure of NK cell-mediated immunoediting. Whereas most tumour cell clones were efficiently eliminated by NK cells, a certain fraction of tumour cells harboured an intrinsic primary resistance. Furthermore, DNA barcoding revealed tumour cell clones with secondary resistance, which stochastically acquired resistance to NK cells. NK cell cytotoxicity put a selective pressure on B-ALL cells, which led to an outgrowth of primary and secondary resistant tumour cell clones, which were characterised by an IFN-{gamma} signature. Besides well-known regulators of immune evasion, our analysis of NK cell resistant tumour cells revealed the upregulation of genes, including Ly6a, which we found to promote NK cell resistance in leukaemic cells. Translation of our findings to the human system showed that high expression of LY6E on tumour cells impaired the physical interaction with NK cells and led to worse prognosis in leukaemia patients. Our results demonstrate that tumour cells are actively edited by NK cells during the equilibrium phase and use different avenues to escape NK cell-mediated eradication.

cancer biology↗

bioRxiv2023

A lineage-specific STAT5BN642H mouse model to study NK-cell leukemia

Patients with T- and NK-cell neoplasms frequently have somatic STAT5B gain-of-function mutations. The most frequent STAT5B mutation is STAT5BN642H, which is known to drive murine T-cell leukemia although its role in NK-cell malignancies is unclear. Introduction of the STAT5BN642H mutation into human NK-cell lines enhances their potential to induce leukemia in mice. We have generated a mouse model that enables tissue-specific expression of STAT5BN642H and have selectively expressed the mutated STAT5B in hematopoietic cells (N642Hvav/+) or exclusively in NK cells (N642HNK/NK). All N642Hvav/+ mice rapidly develop an aggressive T-/NK T-cell leukemia, whereas N642HNK/NK mice display an indolent chronic lymphoproliferative disorder of NK cells (CLPD-NK) that progresses to an aggressive leukemia with age. Samples from NK-cell leukemia patients have a distinctive transcriptional signature driven by mutant STAT5B, which overlaps with that of murine STAT5BN642H-expressing NK cells. We have generated the first reliable STAT5BN642H-driven pre-clinical mouse model that displays an indolent CLPD-NK progressing to aggressive NK-cell leukemia. This novel in vivo tool will enable us to explore the transition from an indolent to an aggressive disease and will thus permit the study of prevention and treatment options for NK-cell malignancies. Key pointsO_LIGeneration of a lineage-specific STAT5BN642H transgenic mouse model which develops NK-cell leukemia C_LIO_LILeukemic NK cells with a STAT5B gain of function mutation have a unique transcriptional profile in mice and human patients C_LI

cancer biology↗