We exploited previously-published in vitro characterization in the biochemical steps involved in doxorubicin bioactivation to create models that had been exact for patient-derived ALL cell lines. Our model findings, confirmed in two cell lines, indicate that doxorubicin metabolism can shift in between NADPH-dependent reductive conversion, which drives doxorubicin toxicity in leukemia cells, and NADPH-dependent superoxide generation, which drives doxorubicin-dependent signaling. Nonintuitively, NADPH-dependent ROS production is related with safety towards doxorubicin-induced cell death. Moreover, redox manage over doxorubicin bioactivation is regulated not just from the enzymatic reactions that get spot within the cell, but also by the concentration of doxorubicin to which the cell is exposed.
Results A computational model describes in vitro doxorubicin bioactivation To investigate the mechanisms that control doxorubicin bioactivation, we formulated a kinetic compound libraries mathematical model within the doxorubicin bioactivation network in a cell cost-free strategy . From right here on, we shall use the term in vitro to refer to acellular systems as well as term in vivo to refer to cellular programs. Our in vitro model was applied to reproduce previously published in vitro data generated by Kostrzewa-Nowak et al for the effect of NADPH concentration on doxorubicin bioactivation . In the model, we permitted for the reaction of NADPH with molecular oxygen, but assumed it to be non-enzymatic since NADPH oxidase was not existing during the cell free of charge response mixtures.
The inclusion of your NADPH/O2 reaction from the bioactivation network model was especially necessary because it supplied a mechanistic pathway by which increased NADPH concentration could lead to enhanced doxorubicin reductive conversion. Reductive conversion of doxorubicin is characterized by conservative NADPH depletion and quinone doxorubicin transformation, despite the fact that redox cycling of hop over to here doxorubicin is characterized by fast NADPH depletion and sustained quinone doxorubicin. The completed in vitro model was capable not merely of describing the switch in conduct amongst reductive conversion and redox cycling of doxorubicin based mostly on the substantial and low NADPH concentrations, but was also capable of replicating a new experimental issue. On inclusion of SOD exercise within the bioactivation network, while not refitting the parameters, the model demonstrated SOD-induced redox cycling of doxorubicin at higher NADPH concentration .
Doxorubicin sensitivity and bioactivation network parts differ in EU1 and EU3 ALL cells The validated in vitro model of doxorubicin bioactivation emphasizes the importance of the response between NADPH and molecular oxygen from the correct representation of doxorubicin bioactivation.