Neutrophil Extracellular Traps Are Increased in Chronic Myeloid Leukemia and Are Differentially Affected by Tyrosine Kinase Inhibitors.

Alona Telerman,Galit Granot,Chiya Leibovitch,Pia Raanani,Martin H Ellis,Moshe Yeshurun,Osnat Yarchovsky-Dolberg,Adi Shacham-Abulafia,Ofir Wolach,Shirly Partouche

doi:10.3390/cancers14010119

Alona Telerman, Galit Granot + Show 8 more

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https://doi.org/10.3390/cancers14010119

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Abstract

Simple SummaryNeutrophil extracellular traps (NETs) are a recently described form of neutrophil cellular death that has been associated with a thrombotic tendency in many diseases. We studied NET formation in neutrophils derived from patients with chronic myeloid leukemia (CML) and in CML neutrophil cell lines and demonstrated that NETs are increased in CML and that certain drugs used to treat CML (tyrosine kinase inhibitors—TKIs) increase NET formation. These findings may shed light on a novel mechanism linking CML, TKIs and vascular toxicity.Cardiovascular complications are increasingly reported with the use of certain tyrosine kinase inhibitors (TKIs) to treat chronic myeloid leukemia (CML). We studied neutrophil extracellular trap (NET) formation in CML and evaluated the effect of TKIs on NET formation. Neutrophils isolated from treatment-naïve patients with CML showed a significant increase in NET formation compared to matched controls at baseline and after stimulation with ionomycin (IO) and phorbol 12-myristate 13-acetate (PMA). Expression of citrullinated histone H3 (H3cit), peptidyl arginine deiminase 4 (PAD4) and reactive oxygen species (ROS) was significantly higher in CML samples compared to controls. Pre-treatment of neutrophils with TKIs was associated with a differential effect on NET formation, and ponatinib significantly augmented NET-associated elastase and ROS levels as compared to controls and other TKIs. BCR-ABL1 retroviral transduced HoxB8-immortalized mouse hematopoietic progenitors, which differentiate into neutrophils in-vitro, demonstrated increased H3cit & myeloperoxidase (MPO) expression consistent with excess NET formation. This was inhibited by Cl-amidine, a PAD4 inhibitor, but not by the NADPH inhibitor diphenyleneiodonium (DPI). Ponatinib pre-exposure significantly increased H3cit expression in HoxB8-BCR-ABL1 cells after stimulation with IO. In summary, CML is associated with increased NET formation, which is augmented by ponatinib, suggesting a possible role for NETs in promoting vascular toxicity in CML.

Highlights

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm (MPN) driven by the BCR-ABL1 fusion gene
Demers and colleagues previously demonstrated that neutrophils from a retroviral transduced BCR-ABL1 murine model have an increase in neutrophil extracellular trap (NET) formation [11]
NET formation was significantly increased in neutrophils derived from patients with CML at baseline and even more so after stimulation with IO as assessed by typical morphological changes (p < 0.05 & p < 0.005, respectively; Figure 1A,B), and after stimulation with phorbol 12-myristate 13-acetate (PMA) as assessed by quantification of NET-associated elastase (p < 0.005 & p < 0.005 before and after stimulation, respectively; Figure 1C), as compared to controls

Summary

Introduction

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm (MPN) driven by the BCR-ABL1 fusion gene. Neutrophils can expel extracellular strands of decondensed DNA complexed with histones, myeloperoxidase (MPO) and additional bioactive proteins [7] These structures are able to ensnare and kill microbes but are implicated in the pathogenesis of autoimmunity and thrombosis [8,9]. Intact production of reactive oxygen species (ROS) via nicotinamide adenine dinucleotide phosphate (NADPH) oxidase [10] and peptidylarginine deiminase 4 (PAD4)-dependent NET formation seem to play a central role. Both pathways culminate in chromatin decondensation and NET formation. Increased NET formation has previously been shown to be associated with cancer-associated thrombosis [11], in context of myeloid malignancies, such as Philadelphia-negative myeloproliferative neoplasms [12] and in CML mouse models [11]

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