RUNX1/ETO regulates reactive oxygen species (ROS) levels in t(8,21) acute myeloid leukaemia via FLT3 and RAC1

Reactive oxygen species (ROS) homeostasis is crucial for leukaemogenesisand deregulation would hamper leukaemic progression. Although the regulatory effects of RUNX1/ETO has been extensively studied, its underlying molecular mechanims in ROS production in t(8,21) AML is yet to be fully elucidated. Here, we report that RUNX1/ETO could directly control FLT3 by occupying several DNA elements on FLT3 locus. The possible hijacking mechanism by RUNX1/ETO over FLT3 mediated ROS modulation in AML t(8;21) was made apparent when suppression of RUNX1/ETO led to decrement in ROS levels and the direct oxidative marker FOXO3 but not in FLT3 and RAC1 suppressed t(8,21) AML cell line Furthermore, nuclear import of RUNX1/ETO was aberrated following RUNX1/ETO and RAC1 suppression suggesting association in ROS control. A different picture was depicted in non t(8;21) cells where suppression of RAC1 and FLT3 led to decreased levels of FOXO3a and ROS. Results alltogether indicate a possible dysregulation of ROS levels by RUNX1/ETO in t(8,21) AML.

Automated summary

In t(8;21) AML, RUNX1/ETO directly controls FLT3 and mediates ROS regulation by occupying DNA elements on the FLT3 locus. Suppression of RUNX1/ETO leads to decreased ROS levels and FOXO3 expression, but not FLT3 and RAC1. Nuclear import of RUNX1/ETO is aberrated following its suppression, suggesting its association in ROS control. In non t(8;21) cells, suppression of RAC1 and FLT3 decreases FOXO3a and ROS levels. These results indicate a possible dysregulation of ROS levels by RUNX1/ETO in t(8;21) AML.