Ponatinib Activates an Inflammatory Response in Endothelial Cells via ERK5 SUMOylation

Abstract

Ponatinib is a multi-targeted third generation tyrosine kinase inhibitor (TKI) used in the treatment of chronic myeloid leukemia (CML) patients harboring the Abelson (Abl)-breakpoint cluster region (Bcr) T315I mutation. In spite of having superb clinical efficacy, ponatinib triggers severe vascular adverse events (VAEs) that significantly limit its therapeutic potential. On vascular endothelial cells (ECs), ponatinib promotes EC dysfunction and apoptosis, and inhibits angiogenesis. Furthermore, ponatinib-mediated anti-angiogenic effect has been suggested to play a partial role in systemic and pulmonary hypertension via inhibition of vascular endothelial growth factor receptor 2 (VEGFR2). Even though ponatinib-associated VAEs are well documented, their etiology remains largely unknown, making it difficult to efficiently counteract treatment-related adversities. Therefore, a better understanding of the mechanisms by which ponatinib mediates VAEs is critical. In cultured human aortic ECs (HAECs) treated with ponatinib, we found an increase in nuclear factor NF-kB/p65 phosphorylation and NF-kB activity, inflammatory gene expression, cell permeability, and cell apoptosis. Mechanistically, ponatinib abolished extracellular signal-regulated kinase 5 (ERK5) transcriptional activity even under activation by its upstream kinase mitogen-activated protein kinase kinase 5α (CA-MEK5α). Ponatinib also diminished expression of ERK5 responsive genes such as Krüppel-like Factor 2/4 (klf2/4) and eNOS. Because ERK5 SUMOylation counteracts its transcriptional activity, we examined the effect of ponatinib on ERK5 SUMOylation, and found that ERK5 SUMOylation is increased by ponatinib. We also found that ponatibib-mediated increased inflammatory gene expression and decreased anti-inflammatory gene expression were reversed when ERK5 SUMOylation was inhibited endogenously or exogenously. Overall, we propose a novel mechanism by which ponatinib up-regulates endothelial ERK5 SUMOylation and shifts ECs to an inflammatory phenotype, disrupting vascular homeostasis.

The Risk of Arterial Thrombosis in Patients With Chronic Myeloid Leukemia Treated With Second and Third Generation BCR-ABL Tyrosine Kinase Inhibitors May Be Explained by Their Impact on Endothelial Cells: An In-Vitro Study

“…Our study further provides insights about the mechanisms by which ponatinib dose-dependently affects endothelial cell viability. Ponatinib induced necrosis without increasing ROS levels, and might participate in atherosclerosis by this way ( Paez-Mayorga et al., 2018 ). The identification of the type of endothelial cell death induced by ponatinib supports at least two hypotheses regarding the molecular signaling pathways responsible for this effect.…”

Therapeutic Inhibition of VEGF Signaling and Associated Nephrotoxicities

“…There are reports of the TKIs dasatinib and ponatinib inducing pulmonary arterial hypertension after their use in patients, 83 and ponatinib administered to cultured human aortic endothelial cells has been similarly associated with decreased NOS3 expression. 84 In light of eNOS's essential role of in regulating vascular endothelial integrity through VEGF signaling, it is important to consider the contribution of other key endothelial regulatory genes in this pathway. Krüppel-like factor 2 (KLF2) and Krüppellike factor 4 (KLF4) are well known zincfinger transcription factors that regulate anti-inflammatory 85,86 and antithrombotic 87 pathways in the endothelium.…”

Ponatinib and other CML Tyrosine Kinase Inhibitors in Thrombosis

“…As ponatinib uniquely inhibits a number of signaling systems that influence the vessel wall (FGFR, VEGFR, PDGFR, and Tie2) ( Table 1) and inhibition of Abl1 kinase negative effects in endothelium [25,27], investigations examined if steady−state levels of ponatinib influence vessel wall biology [104][105][106]. Investigations determined if the aorta from ponatinib−treated mice show evidence of apoptosis and increased reactive oxygen species.…”