Defining the cancer-specific proteome in Calreticulin-mutant myeloproliferative neoplasms
Final Report Abstract
Calreticulin (CALR) mutations are frequent, disease-initiating events in myeloproliferative neoplasms (MPN). Although the biological mechanism by which CALR mutations cause MPN has been elucidated, there currently are no clonally selective therapies for CALR-mutant MPN. Although the mechanism of mutant CALR-induced MPN is known to involve pathogenic binding between mutant CALR and MPL, this insight has not yet been exploited therapeutically. Although patients with myelofibrosis (MF) harboring mutations in CALR demonstrate clinical responses to the JAK2 inhibitor, ruxolitinib, the mutant CALR variant allele fraction (VAF) does not decline with ruxolitinib treatment. More recently, similar findings have been reported for CALR-mutant MPN treated with pegylated interferon (i.e. clinical responses in the absence of a decline in mutant CALR VAF). Indeed, a major deficiency in the treatment of MPN more broadly is the lack of clonally selective therapeutic agents with curative potential. Hence, we set out to discover and validate unique genetic dependencies for mutant CALR-driven oncogenesis. To identify novel genetic dependencies in CALR-mutant MPN, we performed a whole-genome CRISPR knockout depletion screen in mutant CALR-transformed hematopoietic cells. We found that genes in the N-glycosylation pathway (amongst others) were differentially depleted in mutant CALR-transformed cells as compared with control cells. Using a focused pharmacological screen targeting unique vulnerabilities uncovered in the CRISPR screen, we found that chemical inhibition of N-glycosylation impaired the growth of mutant CALR-transformed cells in vitro. We treated Calr-mutant knockin mice with the N-glycosylation inhibitor, 2-deoxy-glucose (2-DG), and found a preferential sensitivity of Calr-mutant cells to 2-DG as compared to wild-type cells, and a normalization of key MPN disease features. These findings have implications for the treatment of CALR-mutant MPN patients. Taken together, using unbiased approaches, we have (i) identified differential genetic vulnerabilities of mutant CALR-transformed hematopoietic cells, (ii) validated that transformation by mutant CALR is dependent on Dpm2, a key gene in the N-glycan biosynthesis pathway and (iii) shown that inhibition of N-glycosylation normalizes key features of MPN and preferentially targets Calr-mutant cells in vivo.
Publications
- CL-XL expression is essential for human erythropoiesis and engraftment of hematopoietic stem cells. Cell Death Dis. 2020 Jan 6;11(1):8
Afreen S, Bohler S, Müller A, Demmerath EM, Weiss JM, Jutzi JS, Schachtrup K, Kunze M, Erlacher M
(See online at https://doi.org/10.1038/s41419-019-2203-z) - Enhanced expression of the sphingosine-1-phosphate-receptor-3 causes acute myelogenous leukemia in mice. Leukemia. 2020 Mar;34(3):721-734
Vorbach S, Gründer A, Zhou F, Koellerer C, Jutzi JS, Simoni M, Riccetti L, Valk PJ, Sanders MA, Müller-Tidow C, Nofer JR, Pahl HL
(See online at https://doi.org/10.1038/s41375-019-0577-7) - Jmjd1c is dispensable for healthy adult hematopoiesis and Jak2V617F-driven myeloproliferative disease initiation in mice. PLoS One. 2020 Feb 4;15(2):e0228362
Staehle HF, Heinemann J, Gruender A, Omlor AM, Pahl HL, Jutzi JS
(See online at https://doi.org/10.1371/journal.pone.0228362) - Remodeling the Bone Marrow Microenvironment - A Proposal for Targeting Pro-inflammatory Contributors in MPN. Front Immunol. 2020 Aug 31;11:2093
Jutzi JS, Mullally A
(See online at https://doi.org/10.3389/fimmu.2020.02093) - The Cross Marks the Spot: The Emerging Role of JmjC Domain-Containing Proteins in Myeloid Malignancies. Biomolecules. 2021 Dec 20;11(12):1911
Staehle HF, Pahl HL, Jutzi JS
(See online at https://doi.org/10.3390/biom11121911)
