Details

Autor(en) / Beteiligte

• Foßelteder, Johannes
• Pabst, Gabriel
• Sconocchia, Tommaso
• Schlacher, Angelika
• Auinger, Lisa
• Kashofer, Karl
• Beham-Schmid, Christine
• Trajanoski, Slave
• Waskow, Claudia
• Schöll, Wolfgang
• Sill, Heinz
• Zebisch, Armin
• Wölfler, Albert
• Thomas, Daniel
• Reinisch, Andreas

Titel

Human gene-engineered calreticulin mutant stem cells recapitulate MPN hallmarks and identify targetable vulnerabilities

Ist Teil von

• Leukemia, 2023-04, Vol.37 (4), p.843-853

Ort / Verlag

London: Nature Publishing Group UK

Erscheinungsjahr

2023

Quelle

MEDLINE

Beschreibungen/Notizen

• Calreticulin ( CALR ) mutations present the main oncogenic drivers in JAK2 wildtype (WT) myeloproliferative neoplasms (MPN), including essential thrombocythemia and myelofibrosis, where mutant (MUT) CALR is increasingly recognized as a suitable mutation-specific drug target. However, our current understanding of its mechanism-of-action is derived from mouse models or immortalized cell lines, where cross-species differences, ectopic over-expression and lack of disease penetrance are hampering translational research. Here, we describe the first human gene-engineered model of CALR MUT MPN using a CRISPR/Cas9 and adeno-associated viral vector-mediated knock-in strategy in primary human hematopoietic stem and progenitor cells (HSPCs) to establish a reproducible and trackable phenotype in vitro and in xenografted mice. Our humanized model recapitulates many disease hallmarks: thrombopoietin-independent megakaryopoiesis, myeloid-lineage skewing, splenomegaly, bone marrow fibrosis, and expansion of megakaryocyte-primed CD41 + progenitors. Strikingly, introduction of CALR mutations enforced early reprogramming of human HSPCs and the induction of an endoplasmic reticulum stress response. The observed compensatory upregulation of chaperones revealed novel mutation-specific vulnerabilities with preferential sensitivity of CALR mutant cells to inhibition of the BiP chaperone and the proteasome. Overall, our humanized model improves purely murine models and provides a readily usable basis for testing of novel therapeutic strategies in a human setting.