Cytotoxic effect of PI3Kδ inhibitor in acute promyelocytic leukemia cells

Background and ObjectivesPI3K/Akt pathway plays a key role in cell growth and proliferation. Constitutive activation of this pathway is detectable in 50-70% of patients with acute promyelocytic leukemia (APL). Previous studies showed that PI3K activity in APL cells is mainly due to overexpression of p110δ isoform. In an effort to investigate the effect of PI3K inhibition in acute promyelocytic leukemia, APL-derived NB4 cells were subjected to different concentrations of Idelalisib, as a potent p110δ-specific inhibitor.
Materials and MethodsIn this experimental study, we examined the effect of Idelalisib on the viability and metabolic activity of NB4 cells. Moreover, flowcytometery and quantitative RQ-PCR were applied to investigate both induction of apoptosis and transcriptional activity of apoptosis-related genes, respectively.
Results The results revealed that Idelalisib not only decreased cell viability and metabolic activity in a dose- and time-dependent manner, but also induced cell death through the apoptotic pathway in NB4 cells. Our data also delineated that Idelalisib-induced apoptosis was mediated through induction of Bax and PUMA coupled with decreased expression of Mcl-1.
ConclusionsBased on P110δ activity in APL patients and the potent efficacy of Idelalisib in NB4 cells, it is tempting to suggest this inhibitor, as either single agent or in combination with common medications, for the treatment of patients with APL.