scholarly journals Dual targeting of JAK2 and ERK interferes with the myeloproliferative neoplasm clone and enhances therapeutic efficacy

Leukemia ◽  
2021 ◽  
Author(s):  
Sime Brkic ◽  
Simona Stivala ◽  
Alice Santopolo ◽  
Jakub Szybinski ◽  
Sarah Jungius ◽  
...  
Keyword(s):  
Therapeutic Efficacy ◽  
Mapk Pathway ◽  
Myeloproliferative Neoplasms ◽  
Myeloproliferative Neoplasm ◽  
Term Treatment ◽  
Wild Type ◽  
Jak2 Inhibitor ◽  
Dual Targeting ◽  
Clinical Benefits ◽  
Jak2 Inhibition

AbstractMyeloproliferative neoplasms (MPN) show dysregulated JAK2 signaling. JAK2 inhibitors provide clinical benefits, but compensatory activation of MAPK pathway signaling impedes efficacy. We hypothesized that dual targeting of JAK2 and ERK1/2 could enhance clone control and therapeutic efficacy. We employed genetic and pharmacologic targeting of ERK1/2 in Jak2V617F MPN mice, cells and patient clinical isolates. Competitive transplantations of Jak2V617F vs. wild-type bone marrow (BM) showed that ERK1/2 deficiency in hematopoiesis mitigated MPN features and reduced the Jak2V617F clone in blood and hematopoietic progenitor compartments. ERK1/2 ablation combined with JAK2 inhibition suppressed MAPK transcriptional programs, normalized cytoses and promoted clone control suggesting dual JAK2/ERK1/2 targeting as enhanced corrective approach. Combined pharmacologic JAK2/ERK1/2 inhibition with ruxolitinib and ERK inhibitors reduced proliferation of Jak2V617F cells and corrected erythrocytosis and splenomegaly of Jak2V617F MPN mice. Longer-term treatment was able to induce clone reductions. BM fibrosis was significantly decreased in MPLW515L-driven MPN to an extent not seen with JAK2 inhibitor monotherapy. Colony formation from JAK2V617F patients’ CD34+ blood and BM was dose-dependently inhibited by combined JAK2/ERK1/2 inhibition in PV, ET, and MF subsets. Overall, we observed that dual targeting of JAK2 and ERK1/2 was able to enhance therapeutic efficacy suggesting a novel treatment approach for MPN.

scholarly journals THE JAK2V617F POINT MUTATION INCREASES THE OSTEOCLAST FORMING ABILITY OF MONOCYTES IN PATIENTS WITH CHRONIC MYELOPROLIFERATIVE NEOPLASMS AND MAKES THEIR OSTEOCLASTS MORE SUSCEPTIBLE TO JAK2 INHIBITION

2018 ◽  
Vol 10 ◽  
pp. e2018058
Author(s):  
Emmanouil Spanoudakis ◽  
Menelaos Papoutselis ◽  
Ioanna Bazntiara ◽  
Eleftheria Lamprianidou ◽  
Xrisa Kordella ◽  
...  
Keyword(s):  
Point Mutation ◽  
Genomic Dna ◽  
Myeloproliferative Neoplasms ◽  
Myeloproliferative Neoplasm ◽  
Cellular Level ◽  
Hemopoietic Stem Cell ◽  
Jak2 Inhibitor ◽  
Chronic Myeloproliferative Neoplasms ◽  
Cell Niche ◽  
Jak2 Inhibition

JAK2V617F is a gain of function point mutation that occurs in Myeloproliferative Neoplasm (MPN) patients and deranges their hemopoiesis at cellular level. We speculate that hyperfunctioning JAK2 can modify osteoclast (OCL) homeostasis in MPN patients. We studied 18 newly diagnosed MPN patients and four age-matched normal donors (ND). Osteoclast forming assays started from selected monocytes also and under titrated concentrations of the JAK2 Inhibitor AG-490 (Tyrphostin). Genomic DNA was extracted from the formed osteoclasts, and the JAK2V617F/JAK2WT genomic DNA ratio was calculated. OCLs formed from monocytes derived from heterozygous (Het) for the JAK2V617F mutation MPN patients, were three times more compared to those from JAK2 wild type (WT) MPN patients (p=0,05) and from ND as well (p=0,03). The ratio of JAK2V617F/JAK2WT genomic DNA was increased in OCLs compared to the input monocyte cells showing a survival advantage of the mutated clone. In comparison to ND and JAK2 WT MPN patients, OCLs from patients JAK2V617F (Het) were more susceptible to JAK2 inhibition. These alterations in osteoclast homeostasis, attributed to mutated JAK2, can deregulate the hemopoietic stem cell niche in MPN patients.

scholarly journals Determining the role of inflammation in the selection of JAK2 mutant cells in myeloproliferative neoplasms

2016 ◽  
Author(s):  
Jie Zhang ◽  
Angela Fleischman ◽  
Dominik Wodarz ◽  
Natalia L. Komarova
Keyword(s):  
Myeloproliferative Neoplasms ◽  
Hematologic Malignancy ◽  
Clonal Evolution ◽  
Myeloproliferative Neoplasm ◽  
Wild Type ◽  
Hematopoietic Stem ◽  
Evolutionary Advantage ◽  
Functional Forms ◽  
Mutant Cells

AbstractMyeloproliferative neoplasm (MPN) is a hematologic malignancy characterized by the clonal outgrowth of hematopoietic cells with a somatically acquired mutation most commonly in JAK2 (JAK2V 617F). This mutation endows upon myeloid progenitors cytokine independent growth and consequently leads to excessive production of myeloid lineage cells. It has been previously suggested that inflammation may play a role in the clonal evolution of JAK2V 617F mutants. In particular, it is possible that one or more cellular kinetic parameters of hematopoietic stem cells (HSCs) are affected by inflammation, such as division or death rates of cells, and the probability of HSC differentiation. This suggests a mechanism that can steer the outcome of the cellular competition in favor of the mutants, initiating the disease. In this paper we create a number of mathematical evolutionary models, from very abstract to more concrete, that describe cellular competition in the context of inflammation. It is possible to build a model axiomatically, where only very general assumptions are imposed on the modeling components and no arbitrary (and generally unknown) functional forms are used, and still generate a set of testable predictions. In particular, we show that, if HSC death is negligible, the evolutionary advantage of mutant cells can only be conferred by an increase in differentiation probability of HSCs in the presence of inflammation, and if death plays a significant role in the dynamics, an additional mechanism may be an increase of HSC’s division-to-death ratio in the presence of inflammation. Further, we show that in the presence of inflammation, the wild type cell population is predicted to shrink under inflammation (even in the absence of mutants). Finally, it turns out that if only the differentiation probability is affected by the inflammation, then the resulting steady state population of wild type cells will contain a relatively smaller percentage of HSCs under inflammation. If the division-to-death rate is also affected, then the percentage of HSCs under inflammation can either decrease or increase, depending on other parameters.

Inhibition of JAK2 V617F-Induced Erythroid Skewing of Hematopoietic Stem Cell Differentiation with a Selective JAK2 Antagonist.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3616-3616 ◽  
Author(s):  
Ifat Geron ◽  
Charlene Barroga ◽  
Jason Gotlib ◽  
Edward Kavalerchik ◽  
Annelie Abrahamsson ◽  
...  
Keyword(s):  
Cord Blood ◽  
Colony Formation ◽  
Jak2 V617f ◽  
Wild Type ◽  
Specific Primers ◽  
Jak2 Inhibitor ◽  
Peripheral Blood Cd34 ◽  
Cd34 Cells ◽  
Jak2 Inhibition

Abstract Introduction Polycythemia vera (PV) is characterized by excessive production of erythroid cells and in most cases a point mutation (V617F) in the Jak2 cytokine signaling kinase. We investigated whether a selective JAK2 inhibitor decreased Jak2 V617F induced erythroid differentiation. Methods Wild-type and mutant Jak2 V617F genes were excised from the retroviral Jak2-mus-MSCV-neo vector (Levine et al), cloned into the lentiviral vector pLV CMV IRES2 GFP and their presence verified by DNA sequencing. Lentiviral vectors bearing the wild-type and mutant Jak2 genes or vector alone were used to transduce human peripheral blood CD34+ cells, which were then divided for plating into megacult medium for megakaryocytic colony growth and methylcellulose culture for enumeration of all other progenitor cell types. Normal cord blood HSC (CD34+/CD38−/CD90+) were clone sorted with the FACS Aria and transduced with no vector, backbone vector, wild-type JAK2 or mutant JAK2 vector in methocult media (Stem Cell Technologies Inc, GF+ H4435) +/− 300 nM of a selective JAK2 inhibitor, TG101348. Colonies were scored at day 14. RNA was isolated from the colonies (Qiagen RNeasy kit) and RT-PCR was performed with wild-type and mutant JAK2 allele specific primers. Results Transduction of cord blood HSC with the mutant Jak2 vector resulted in skewed erythroid colony formation compared to wild-type Jak2, vector alone and untransduced HSC (Figure 1; n=3). RT-PCR with murine Jak2 specific primers resulted in ~900 bp fragments corresponding to murine Jak2 from colonies transduced with the wild-type and mutant Jak2 and confirmed by sequencing, but not those from colonies transduced with the vector alone or the untransduced cells. Like the results in cord blood cells, adult peripheral blood CD34+ cells transduced with the mutant Jak2 developed a skewed developmental pattern, with far greater erythroid colony formation compared to wild-type Jak2 or vector alone. In megacult assays, CD34+ cells transduced with the mutant Jak2 had similar megakaryocytic potential as wild-type Jak2 or vector alone. Addition of TG101348 (300 nM), inhibited mutant kinase-induced erythroid colony formation (Figure 1) in 3 experiments while 100– 300 nM was inhibitory to PV (n=2 patients) HSC and progenitors. Current experiments focus on inhibition of Jak2 in a bioluminescent highly immunocompromised mouse model of Jak2V617F-induced myeloproliferation (Figure 2). Conclusion JAK2 V617F skews differentiation of HSC toward the erythroid lineage and may be inhibited with a selective JAK2 inhibitor - TG101348. Figure 1. In vitro JAK2 Inhibition. Figure 1. In vitro JAK2 Inhibition. Figure 2. Bioluminescent JAK2 V617F-induced Myeloproliferation Model. Figure 2. Bioluminescent JAK2 V617F-induced Myeloproliferation Model.

scholarly journals Cell competition between wild-type and JAK2V617F mutant cells in a murine model of a myeloproliferative neoplasm

2020 ◽  
Author(s):  
Melissa Castiglione ◽  
Haotian Zhang ◽  
Huichun Zhan
Keyword(s):  
Stem Cell ◽  
Myeloproliferative Neoplasms ◽  
Myeloproliferative Neoplasm ◽  
List Type ◽  
Wild Type ◽  
Hematopoietic Stem ◽  
Increased Risk ◽  
Mutant Cells

AbstractThe myeloproliferative neoplasms (MPNs) are clonal stem cell disorders characterized by overproduction of mature blood cells and increased risk of transformation to frank leukemia. The acquired kinase mutation JAK2V617F plays a central role in a majority of these disorders. The hematopoietic stem cell (HSC) compartment in MPN is heterogeneous with the presence of both JAK2 wild-type and JAK2V617F mutant cells in most patients with MPN. Utilizing in vitro co-culture assays and in vivo competitive transplantation assays, we found that the presence of wild-type cells altered the behavior of co-existing JAK2V617F mutant cells, and a mutant microenvironment (niche) could overcome the competition between wild-type and mutant cells, leading to mutant clonal expansion and overt MPN. We also demonstrated that competition between wild-type and JAK2V617F mutant cells triggered a significant immune response, and there was a dynamic PD-L1 deregulation in the mutant stem/progenitor cells caused by their interactions with the neighboring wild-type cells and the microenvironment. Therefore, while accumulation of oncogenic mutations is unavoidable during aging, our data suggest that, if we could therapeutically enhance normal cells’ ability to compete, we might be better able to control neoplastic cell expansion and prevent the development of a full-blown malignancy.Key PointsThe presence of wild-type cells alters the behavior of co-existing JAK2V617F mutant cellsA mutant microenvironment overcomes the competition between wild-type and JAK2V617F mutant cells, leading to the development of a MPN

Clonal analysis of TET2 and JAK2 mutations suggests that TET2 can be a late event in the progression of myeloproliferative neoplasms

Blood ◽  
2010 ◽  
Vol 115 (10) ◽  
pp. 2003-2007 ◽  
Author(s):  
Franz X. Schaub ◽  
Renate Looser ◽  
Sai Li ◽  
Hui Hao-Shen ◽  
Thomas Lehmann ◽  
...  
Keyword(s):  
Temporal Order ◽  
Myeloproliferative Neoplasms ◽  
Myeloproliferative Neoplasm ◽  
Jak2 V617f ◽  
Hematologic Malignancies ◽  
Suppressor Gene ◽  
Wild Type ◽  
Tet2 Mutation ◽  
Late Event ◽  
Opposite Order

Abstract Somatic mutations in TET2 occur in patients with myeloproliferative neoplasms and other hematologic malignancies. It has been suggested that TET2 is a tumor suppressor gene and mutations in TET2 precede the acquisition of JAK2-V617F. To examine the order of events, we performed colony assays and genotyped TET2 and JAK2 in individual colonies. In 4 of 8 myeloproliferative neoplasm patients, we found that some colonies with mutated TET2 carried wild-type JAK2, whereas others were JAK2-V617F positive, indicating that TET2 occurred before JAK2-V617F. One of these patients carried a germline TET2 mutation. However, in 2 other patients, we obtained data compatible with the opposite order of events, with JAK2 exon 12 mutation preceding TET2 mutation in one case. Finally, in 2 of 8 patients, the TET2 and JAK2-V617F mutations defined 2 separate clones. The lack of a strict temporal order of occurrence makes it unlikely that mutations in TET2 represent a predisposing event for acquiring mutations in JAK2.

scholarly journals Therapeutic potential of JAK2 inhibitors

Hematology ◽  
2009 ◽  
Vol 2009 (1) ◽  
pp. 636-642 ◽  
Author(s):  
Srdan Verstovsek
Keyword(s):  
Therapeutic Potential ◽  
Myeloproliferative Neoplasms ◽  
Primary Myelofibrosis ◽  
Binding Pocket ◽  
Therapeutic Benefit ◽  
Wild Type ◽  
Competitive Inhibitors ◽  
Clinical Benefits ◽  
Kinase Mutation ◽  
Jak2 Inhibitors

AbstractThe discovery of an activating tyrosine kinase mutation JAK2V617F in myeloproliferative neoplasms (MPNs), polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF) has resulted in the development of JAK2 inhibitors, of which several are being evaluated in phase I/II clinical studies. It is important to recognize that because the V617F mutation is localized in a region outside the adenosine triphosphate (ATP)-binding pocket of JAK2 enzyme, ATP-competitive inhibitors of JAK2 kinase (like the current JAK2 inhibitors in the clinic) are not likely to discriminate between wild-type and mutant JAK2 enzymes. Therefore, JAK2 inhibitors, by virtue of their near equipotent activity against wild-type JAK2 that is important for normal hematopoiesis, may have adverse myelosuppression as an expected side effect, if administered at doses that aim to completely inhibit the mutant JAK2 enzyme. While they may prove to be effective in controlling hyperproliferation of hematopoietic cells in PV and ET, they may not be able to eliminate mutant clones. On the other hand, JAK inhibitors may have great therapeutic benefit by controlling the disease for patients with MPNs who suffer from debilitating signs (eg, splenomegaly) or constitutional symptoms (which presumably result from high levels of circulating cytokines that signal through JAK enzymes). Indeed, the primary clinical benefits observed so far in MF patients have been significant reduction is splenomegaly, elimination of debilitating disease-related symptoms, and weight gain. Most importantly, patients with and without the JAK2V617F mutation appear to benefit to the same extent. In this review we summarize current clinical experience with JAK2 inhibitors in MPNs.

scholarly journals Dual Targeting of Oncogenic Activation and Inflammatory Signaling Increases Therapeutic Efficacy in Myeloproliferative Neoplasms

Cancer Cell ◽  
2018 ◽  
Vol 33 (4) ◽  
pp. 785-787 ◽  
Author(s):  
Maria Kleppe ◽  
Richard Koche ◽  
Lihua Zou ◽  
Peter van Galen ◽  
Corinne E. Hill ◽  
...  
Keyword(s):  
Therapeutic Efficacy ◽  
Myeloproliferative Neoplasms ◽  
Inflammatory Signaling ◽  
Dual Targeting

scholarly journals Dual Targeting of Oncogenic Activation and Inflammatory Signaling Increases Therapeutic Efficacy in Myeloproliferative Neoplasms

Cancer Cell ◽  
2018 ◽  
Vol 33 (1) ◽  
pp. 29-43.e7 ◽  
Author(s):  
Maria Kleppe ◽  
Richard Koche ◽  
Lihua Zou ◽  
Peter van Galen ◽  
Corinne E. Hill ◽  
...  
Keyword(s):  
Therapeutic Efficacy ◽  
Myeloproliferative Neoplasms ◽  
Inflammatory Signaling ◽  
Dual Targeting

R723, a selective JAK2 inhibitor, effectively treats JAK2V617F-induced murine myeloproliferative neoplasm

Blood ◽  
2011 ◽  
Vol 117 (25) ◽  
pp. 6866-6875 ◽  
Author(s):  
Kotaro Shide ◽  
Takuro Kameda ◽  
Vadim Markovtsov ◽  
Haruko K. Shimoda ◽  
Elizabeth Tonkin ◽  
...  
Keyword(s):  
Mouse Model ◽  
Myeloproliferative Neoplasms ◽  
Myeloproliferative Neoplasm ◽  
Primary Myelofibrosis ◽  
Tumor Burden ◽  
Jak2 Inhibitor ◽  
Activating Mutations ◽  
Orally Bioavailable

Abstract The activating mutations in JAK2 (including JAK2V617F) that have been described in patients with myeloproliferative neoplasms (MPNs) are linked directly to MPN pathogenesis. We developed R723, an orally bioavailable small molecule that inhibits JAK2 activity in vitro by 50% at a concentration of 2nM, while having minimal effects on JAK3, TYK2, and JAK1 activity. R723 inhibited cytokine-independent CFU-E growth and constitutive activation of STAT5 in primary hematopoietic cells expressing JAK2V617F. In an anemia mouse model induced by phenylhydrazine, R723 inhibited erythropoiesis. In a leukemia mouse model using Ba/F3 cells expressing JAK2V617F, R723 treatment prolonged survival and decreased tumor burden. In V617F-transgenic mice that closely mimic human primary myelofibrosis, R723 treatment improved survival, hepatosplenomegaly, leukocytosis, and thrombocytosis. R723 preferentially targeted the JAK2-dependent pathway rather than the JAK1- and JAK3-dependent pathways in vivo, and its effects on T and B lymphocytes were mild compared with its effects on myeloid cells. Our preclinical data indicate that R723 has a favorable safety profile and the potential to become an efficacious treatment for patients with JAK2V617F-positive MPNs.

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