Deregulation of apoptosis-related genes is associated with PRV1 overexpression and JAK2 V617F allele burden in Essential Thrombocythemia and Myelofibrosis

<p>Abstract</p> <p>Background</p> <p>Essential Thrombocythemia (ET) and Primary Myelofibrosis (PMF) are Chronic Myeloproliferative Neoplasms (MPN) characterized by clonal myeloproliferation/myeloaccumulation without cell maturation impairment. The JAK2 V617F mutation and <it>PRV1 </it>gene overexpression may contribute to MPN physiopathology. We hypothesized that deregulation of the apoptotic machinery may also play a role in the pathogenesis of ET and PMF. In this study we evaluated the apoptosis-related gene and protein expression of BCL2 family members in bone marrow CD34⁺hematopoietic stem cells (HSC) and peripheral blood leukocytes from ET and PMF patients. We also tested whether the gene expression results were correlated with JAK2 V617F allele burden percentage, <it>PRV1 </it>overexpression, and clinical and laboratory parameters.</p> <p>Results</p> <p>By real time PCR assay, we observed that <it>A1, MCL1, BIK and BID</it>, as well as <it>A1, BCLW </it>and <it>BAK </it>gene expression were increased in ET and PMF CD34⁺cells respectively, while pro-apoptotic <it>BAX </it>and anti-apoptotic <it>BCL2 </it>mRNA levels were found to be lower in ET and PMF CD34⁺cells respectively, in relation to controls. In patients' leukocytes, we detected an upregulation of anti-apoptotic genes <it>A1, BCL2, BCL-X_L</it>and <it>BCLW</it>. In contrast, pro-apoptotic <it>BID </it>and <it>BIM_EL</it>expression were downregulated in ET leukocytes. Increased BCL-X_Lprotein expression in PMF leukocytes and decreased BID protein expression in ET leukocytes were observed by Western Blot. In ET leukocytes, we found a correlation between JAK2 V617F allele burden and <it>BAX, BIK and BAD </it>gene expression and between <it>A1, BAX </it>and <it>BIK </it>and <it>PRV1 </it>gene expression. A negative correlation between <it>PRV1 </it>gene expression and platelet count was observed, as well as a positive correlation between <it>PRV1 </it>gene expression and splenomegaly.</p> <p>Conclusions</p> <p>Our results suggest the participation of intrinsic apoptosis pathway in the MPN physiopathology. In addition, <it>PRV1 </it>and JAK2 V617F allele burden were linked to deregulation of the apoptotic machinery.</p