We analyzed gene expression in CD34+ peripheral-blood cells from 19 patients with polycythemia vera, using oligonucleotide microarray technology after correcting for potential confounding by sex, since the phenotypic features of the disease differ between men and women.
Treatment of polycythemia vera (PV) and primary myelofibrosis (PMF) CD34(+) cells with low doses of RG7112 and Peg-IFNα 2a before their transplantation into immune-deficient mice decreased the degree of donor-derived chimerism as well as the JAK2V617F allele burden, indicating that these drugs can each alone or in combination deplete MPN HSCs.
Here we demonstrated that elevation of NF-E2 expression in healthy CD34(+) cells to levels observed in PV caused Epo-independent erythroid maturation and expansion of hematopoietic stem cell (HSC) and common myeloid progenitor (CMP) cell numbers.
Genetic or PAD-mediated PP2A reactivation induces Jak2(V617F) inactivation/downregulation and impairs clonogenic potential of Jak2(V617F) cell lines and PV but not normal CD34(+) progenitors.
Treatment with low doses of Peg IFN-α 2a combined with Nutlin-3 increased phospho-p53 and p21 protein levels in PVCD34(+) cells and increased the degree of apoptosis.
Conversely, exposure of polycythemia veraCD34(+) cells to small interfering RNA against pre-miR-16-2 reduced erythroid colonies and largely prevented formation of erythropoietin-independent colonies; myeloid progenitors remained unaffected.
These two 14- and 12-gene sets could separate not only PV from normal CD34(+) specimens, but also other MPN such as essential thrombocytosis and primary myelofibrosis from their normal counterparts.
We evaluated the NOD/SCID engraftment of CD34(+) cells from polycythemia vera (PV) and secondary polycythemia patients (SP) and the JAK2V617F clone before and after transplantation.
The exposure of PVCD34(+) cells to low doses of IFNα and ABT-737 in combination resulted in the reduction of the proportion of JAK2V617F(+) colonies similar to that observed with higher doses of IFNα.
Peripheral blood (PB) CD34(+) cells from patients with polycythemia vera (PV) and primary myelofibrosis (PMF) generated in vitro significantly fewer mast cells (MCs) than normal PB CD34(+) cells.
These factors may contribute to the accumulation of chromosomal aberrations, accumulation of hematopoietic cells (especially of erythropoiesis), and prolongation of CD34+ PBSC life span observed in PV.
Peripheral blood CD34(+) cells isolated from PV patients and healthy controls were grown in liquid culture to expand a population of primary erythroblasts for experiments designed to analyze cellular proliferation, apoptosis, JAK2(V617F) mutation status, cytokine-dependent protein phosphorylation and gene expression profiling using Affymetrix microarrays.
We conclude that the extent of JAK2(V617F) CD34(+) cell clonal dominance is associated with disease phenotype within the MPD and, in PV, is associated with extramedullary disease, leukocytosis, and disease duration.
Moreover, a marked augmentation in HR activity was found in CD34(+)-derived cells isolated from patients with polycythemia vera or primitive myelofibrosis compared with control samples.
Three consecutive polycythemia vera (PV) patients were analyzed before and during pegylated-interferon (rIFNalpha) treatment for the following markers: (1) granulocyte and CD34(+) cell clonality, (2) Jak2V617F expression, (3) PRV-1 mRNA overexpression, and (4) Epo-independent colony (EEC) growth.
The present data suggests the JAK2 V617F allele burden as a key determinant of the degree of myeloproliferation and myeloid metaplasia reflected by significantly higher levels of white blood cell counts (WBC) (P = 0.03), CD34 counts (P = 0.03), lactate dehydrogenase and Polycythemia Rubra Vera gene 1 levels (P = 0.03 and P < 0.00001 respectively), as well as lower platelet counts (P = 0.02) and more cases of splenomegaly (P = 0.001) in homozygous PV patients compared to their heterozygous counterparts.
A JAK2 (V617F) gene dosage effect on both CD34(+) cell counts and granulocyte activation was clearly demonstrated in polycythemia vera, where abnormal patterns were mainly found in patients carrying more than 50% mutant alleles.
In this study selected CD34+ peripheral blood (PB) cells from PV patients, PB healthy donors and patients with secondary polycythemia (SP) were investigated and compared concerning frequency, morphology, antigen expression, transcription of differentiation markers and proliferation as well as apoptosis rate following short-term culture.
No mutations were found in these genes; however, unexpectedly, increased expression of the transcription factor NFI-B was detected in granulocytes and CD34(+) cells in PV with 9pLOH.
Following cDNA subtraction using mRNAs isolated from PV and normal CD34+/CD33- bone-marrow cells, expression of the tumour suppressor H19 was found to be low or absent in the PV sample.
No evidence for an altered mRNA expression or protein level of haematopoietic cell phosphatase in CD34+ bone marrow progenitor cells or mature peripheral blood cells in polycythaemia vera.