Escalated activation ofSTAT3 due to JAK2 V617F activatingmutation causesdownregulation ofPTEN via miRNA 21overexpression

Abstract

Abstract Background Mutations in Janus kinase 2 (JAK2) genes are the genetic characteristic of BCR-ABL1-negative myeloproliferative neoplasms (MPN). JAK2 V617F mutation is frequently found in Polycythemia Vera (PV) and Essential Thrombocythemia (ET). We aimed to determine the effect of JAK2 V617F on expression of phosphatase and tensin homolog (PTEN) and its regulator miR-21. Materials and Methods Seventy two (72) (MPN) patients were screened for JAK2 V617F burden using ASO-PCR. Out of 72 MPN patients, 58 were JAK2 V617F positive and 14 were JAK2 V617F negative. BCR/ABL1 fusion gene transcript screening by multiplex PCR was done to rule out Philadelphia positive MPN. We performed SYBR green based qRT-PCR assay to characterize relative STAT3, PTEN mRNA expression and miR21 expression in 72 MPN patients. Results The mRNA expression levels of STAT3 and PTEN and mi-21 expression in all MPN patients were evaluated and compared withJAK2 (V617F) and JAK2 (WT) MPN patients. We identified that STAT3 mRNA expression was significantly upregulated in patients with JAK2 (V617F) genotype (mean fold±SD=2.14 ±1.2) compared to patients with JAK2 (WT) genotype (mean fold±SD=1.23±0.95). Further, we observed a significantly increased miR 21 expression (mean fold±SD=2.18±0.44) in JAK2 (V617F) patients in comparison to JAK2 (WT) patients (mean fold±SD=1.70±0.49) (p = 0.0003). In addition, we observed that PTEN expression was substantially and significantly downregulated in JAK2 (V617F) patients (mean fold±SD= 1.73 ± 0.36) compared JAK2 (WT) patients (mean fold±SD=2.55 ± 0.25) (p Conclusion In summary, STAT3 activation caused by JAK (V617F) mutation in MPN patients causes overexpression of miR-21 which leads to downregulation of tumour supressor PTEN MPN patients. Thus, our suggests that JAK2 activated STAT3/miRNA-21 may play a valuable prognostic biomarker for MPN.