SRC family kinase inihibitors enhance all-trans-retinoic acid or arsenic trioxide induced differentiation of NB4 Leukemia Cells

Abstract

Background & Aim Background: The Src family kinases (SFK) are non-receptor tyrosine kinases that have been implicated in a variety of process, including proliferation, survival, differentiation and migration. Recent studies showed that inhibition of SFKs resulted in enhancement of retinoic acid-induced myeloid differentiation. In this study, we investigated whether SFK inhibitor PP2 and FDA approved dual Src/ABL inhibitor (bosutinib or dasatinib) could enhance the differentiation of NB4 leukemia cells when combined with all-trans-retinoic acid (ATRA) or arsenic trioxide (ATO). Methods, Results & Conclusion Methods: We demonstrated the SFK inhibitor PP2 enhanced the differentiation of NB4 cells when combined with ATRA or ATO. Subsequently, we investigated whether bosutinib and dasatinib could enhance the differentiation of NB4 cells when combined with ATRA or ATO. The cells were analyzed for myeloid differentiation marker CD11b expression using flow cytometry. These results were confirmed in morphologic analysis by Wright stain and NBT reduction assay. In addition, we attempted to determine the difference in retinoic acid-induced gene expression. Results Our data showed that SFK inhibitor PP2 enhanced myeloid differentiation when combined with ATRA or ATO. The synergistic effect was significantly stronger when PP2 was combined with ATRA and ATO (triple treatment) than when PP2 was combined with ATRA or ATO (dual treatment). The similar results were obtained when bosutinib and dasatinib were applied instead of PP2. Co-treatment with bosutinib plus ATRA or ATO, and dasatinib plus ATRA or ATO resulted in significant enhancement of CD11b-positive cells when compared to the each treatment group in bosutinib, dasatinib, ATRA, or ATO. Also, the synergistic effects of bosutinib and dasatinib in combination with ATRA were greater than in combination with ATO. Conclusions SFK inhibitor PP2 and dual Src/ABL inhibitor (bosutinib or dasatinib) can enhances the differentiation of NB4 leukemia cells when combined ATRA and/or ATO. These findings suggest that ATRA or ATO combinated with dual Src/ABL inhibitors may have therapeutic beneficial for the treatment of APL patients.