Affinity and effect of anticancer drugs on the redox reactivity of hemoglobin

Hemoglobin’s redox reactivity is affected by anticancer drugs of the antitubulin class. Direct binding of these drugs to hemoglobin, with biomedically-relevant affinities, is demonstrated. While this interaction is mostly allosteric, in the case of docetaxel a direct redox reaction is also observed – correlating well with structural differences between the four compounds. A role for Tyr145 in this reactivity is proposed, in line with previous observations of the importance of this aminoacid in the reactivity of Hb towards agents of oxidative stress. A susceptibility of vinorelbin (and to a lower extent of paclitaxel) towards peroxide and peroxidase is shown.