Tyrosine kinases have been implicated in promoting
tumorigenesis of several human
cancers. Exploiting these vulnerabilities has been shown to be an effective anti-
tumor strategy as demonstrated for example by the
Bruton's tyrosine kinase (BTK) inhibitor,
ibrutinib, for treatment of various
blood cancers. Here, we characterize a new multiple
kinase inhibitor,
ARQ531, and evaluate its mechanism of action in preclinical models of
acute myeloid leukemia. Treatment with
ARQ531, by producing global signaling pathway deregulation, resulted in impaired cell cycle progression and survival in a large panel of
leukemia cell lines and patient-derived
tumor cells, regardless of the specific genetic background and/or the presence of bone marrow stromal cells.
RNA-seq analysis revealed that
ARQ531 constrained
tumor cell proliferation and survival through
Bruton's tyrosine kinase and transcriptional program dysregulation, with
proteasome-mediated MYB degradation and depletion of short-lived
proteins that are crucial for
tumor growth and survival, including ERK, MYC and MCL1. Finally,
ARQ531 treatment was effective in a patient-derived
leukemia mouse model with significant impairment of
tumor progression and survival, at tolerated doses. These data justify the clinical development of
ARQ531 as a promising targeted agent for the treatment of patients with
acute myeloid leukemia.