Exposure of HL-60 human leukemic cells to 4-hydroxynonenal promotes the formation of adduct(s) with alpha-enolase devoid of plasminogen binding activity.

4-Hydroxynonenal (HNE), the major product of lipoperoxidation, easily reacts with proteins through adduct formation between its three main functional groups and lysyl, histidyl, and cysteinyl residues of proteins. HNE is considered to be an ultimate mediator of toxic effects elicited by oxidative stress. It can be detected in several patho-physiological conditions, in which it affects cellular processes by addition to functional proteins. We demonstrated by mass spectrometry and confirmed by immunoblotting experiments the formation of HNE-alpha-enolase adduct(s) in HL-60 human leukemic cells. alpha-Enolase is a multifunctional protein that acts as a glycolytic enzyme, transcription factor (c-myc binding protein, MBP-1) and plasminogen receptor. HNE did not affect alpha-enolase enzymatic activity, expression and intracellular localization and did not change the expression and localization of MBP-1 either. Confocal and electronic microscopy results confirmed the plasmamembrane, cytosolic and nuclear localization of alpha-enolase in HL-60 cells and demonstrated that HNE was colocalized with alpha-enolase at the surface of cells, early after its addition. HNE caused a dose-and time-dependent reduction of the binding of plasminogen to alpha-enolase. As a consequence, HNE reduced adhesion of HL-60 cells to endothelial cells (HUVECs). These results could suggest a new role for HNE in the control of tumour growth and invasion.