Dissecting the role of hypoxia-inducible factor (HIF)-regulated metabolic alterations in JAK2V617F, CALRdel52 and MPLW515L mutated myeloproliferative neoplasms (MPN)

• Applicant: Dr. Deniz Gezer
• Subject Area: Hematology, Oncology
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 464779339

Myeloproliferative neoplasms (MPN), comprising polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF), are clonal stem cell disorders of the myeloid lineage characterized by hyperproliferation of mature blood cells. Driver mutations of the genes encoding Janus kinase 2 (with JAK2V617F, most frequent in MPN), calreticulin (CALR) and the thrombopoietin receptor (MPL) have been identified in these diseases. A variety of novel drugs have been used in clinical trials, but none of them has shown the potential to cure MPN patients. Therefore, new therapeutic strategies are urgently needed to be developed that selectively target the malignant clone.We have demonstrated that hypoxia-inducible factor 1 (HIF-1) serves as a potential therapeutic target in JAK2V617F-positive MPN. We have found that the HIF-1 inhibitor echinomycin is able to selectively abrogate bone marrow and peripheral blood mononuclear cells and iPS cell-derived progenitor cells from JAK2V617F-positive patients, while cells from healthy donors were unaffected. Furthermore, we have identified the inhibition of the Warburg effect as a potential underlying mechanism.One aim of this proposal is to unravel whether our hypothesis can be verified, paving the way for the application of glycolysis inhibitors in MPN. We plan to perform energy-metabolic profiling of JAK2V617F-positive cells knockdown/knockout (KD/KO) of HIF-1α or inhibition of HIF-1. To further investigate the underlying mechanism, KD/KO or overexpression studies with HIF-1 target genes that are involved in the Warburg effect will be performed. To investigate the role of HIF-1 for MPN disease establishment in a Jak2V617F-positive in vivo setting, Jak2V617F-transduced hematopoietic stem and progenitor cells from Hif-1α KO or wild-type mice will be transplanted into wild-type mice. The recipient mice will be characterized with respect to engraftment of the Jak2V617F-positive donor cells, disease progression and survival. In a Jak2V617F KI model, we plan to assess the in vivo effect of the HIF-1 inhibitors echinomycin and acriflavine, to determine the impact of pharmacologic inhibition of HIF-1 on disease progression in a Jak2V617F-positive MPN mouse model.Furthermore, we plan to examine the role of HIF-1 in MPN caused by the other two driver mutations that are found in 30% (CALR) and 5% (MPL) of ET and PMF patients. Therefore, we will test the efficacy of HIF-1 inhibition in a CALR and MPL mutated murine cell line model and bone marrow and peripheral blood cells from patients harboring these mutations. In addition to that, we will assess the impact of dual HIF-1/HIF-2 inhibitors to circumvent a potential compensatory mechanism of HIF-2 upregulation in response to HIF-1 inhibition.Collectively, based on our previously published data this project aims to further investigate the implication of targeting HIF-1 in the context of MPN with the goal to conduct a clinical trial with a HIF-1 inhibitor.

• DFG Programme: Research Grants