CML-074 Pathogenesis of Tyrosine Kinase Inhibitor–Associated Vascular Toxicity in Chronic Myeloid Leukemia

Abstract

Evidence has emerged demonstrating an association between treatment with certain tyrosine kinase inhibitors (TKIs) and vascular adverse events (VAEs) in chronic myeloid leukemia (CML). An increase in VAEs has been documented with ponatinib, nilotinib, and dasatinib but not with imatinib and bosutinib. We used an endothelial cell (HUVEC) model and an in-vivo hindlimb ischemia mouse model to study TKI-associated VAEs. We show that compared with control-treated cells, ponatinib increased HUVEC apoptosis by 97% and inhibited their VEGF-induced migration by 35%. HUVEC tube formation was significantly abrogated by ponatinib as evidenced by an 87% reduction in tube number, 68% reduction in segment length, 50% reduction in junction number, and 55% increase in the occurrence of isolated segments. Ponatinib's suppressive effect on tube formation was partially rescued by VEGFR2 overexpression, a known ponatinib off-target. Dasatinib also dramatically disrupted tube formation as evidenced by a 97% reduction in tube number, 95% reduction in segment length, 88% reduction in junction number, and 300% increase in the occurrence of isolated segments. Nilotinib was associated with reduced cell viability, whereas imatinib and bosutinib did not affect these processes. Furthermore, HUVECs treated with ponatinib, dasatinib, and nilotinib revealed a differential angiogenesis-related gene expression pattern. The expression profile of imatinib- and bosutinib-treated cells was similar to that of control-treated cells. In our in-vivo model, unilateral femoral artery excision was performed to induce ischemia and stimulate new blood vessel formation in TKI-treated mice. Imatinib-treated mice showed a similar recovery pattern to that of control mice as assessed via Doppler imager. Bosutinib- and dasatinib-treated mice showed an initial delayed recovery but reached an overall recovery of 85% within 28 days. In contrast, ponatinib-treated mice reached overall perfusion of 60% around day 7 without further improvement. These results are in line with the clinical VAE profiles of ponatinib, dasatinib, and nilotinib, implicating endothelial toxicity related to these TKIs and supporting a direct effect of these TKIs on vascular cells. However, the in-vivo effect of these TKIs on endothelial pathogenesis requires further investigation. Understanding TKI-induced VAE pathogenesis could contribute to the future development of safer next-generation TKIs and could potentially influence TKI-personalized tailoring for CML patients.