CDK2 suppressionsynergizes with all-transretinoic acid toovercome myeloid differentiation blockade of AML cells

OBJECTIVE To investigate the synergistic effect and mechanism of cyclin-dependent kinase 2（CDK2） inhibition and all-trans-retinoic acid（ATRA） in acute myeloid leukemia（AML） cell differentiation. METHODS sh RNAs targeting CDK2 and CDK2 inhibitors were introduced into AML cel s to explore the effect on cel proliferation, cell cycle and cell differentiation upon the ATRA treatment. The m RNA level of STAT1, PU.1 and CEBPβwere detected by quantitative-real-time PCR and protein expression were detected by Western blotting in AML cells when CDK2 were knockout. RNA-sequence analysis was performed to gain specific insight into the mechanism of synergistic effect induced by CDK2 decline with ATRA. NOD/SCID model was gene rated to test whether CDK2 inhibition and ATRA synergized in vivo. RESULTS Both the depletion and pharmacological inhibitor of CDK2 sensitized three subtypes of AML to ATRA-induced cell growth inhibition, G0/G1 phase arrest,CD11 b expression, NBT reduction, mature morphologic changes andmyeloid regulator expression. The m RNA levels of STAT1,PU.1 or CEBPβ were enhanced by sh CDK2. And the RNA-sequence results showed that significant translation activation of differentiation and maturation pathway played an important role on differentiation triggered by CDK2 depletion combined with ATRA. Furthermore, the down-regulation of CDK2 sensitized AML cells to ATRAinduced engraftment prevention of leukemia cells in NOD-SCID mice and promotes the primary AML blasts differentiation when combined with ATRA. CONCLUSION This study estimated the synergism between CDK2 decrease and ATRA in the differentiation induction of AML cells, thus suggesting that CDK2 may be a novel therapeutic target to sensitive non-APL cells to ATRA treatment.