The association between oxidative stress-induced galectins and differentiation of human promyelocytic HL-60 cells

- Differentiation of HL-60 cells involves oxidative stress-sensitive galectins.
- Galectin expression depends on JNK signaling and DNA hypomethylation.
- Galectin inhibition increases HL-60 doubling time and facilitates differentiation.
- Galectins are molecular targets for anti-cancer and anti-inflammatory therapy.

Galectins are multifunctional β-galactoside-binding proteins that are involved in the regulation of cellular stress responses and differentiation. The relationship between these processes is unclear and we report here that galectins display oxidative-stress specific expression patterns in neutrophil-like differentiated HL-60 cells. Three galectins (−1, −3, and −10) are upregulated in response to either menadione or DMSO exposure whereas galectins −9 and −12 exhibited a stimulus-dependent downregulation. Changes in galectin expression are oxidant dependent based on the observations that 1) oxidative stress biomarkers HMOX1 (heme oxygenase-1) and NCF1 (neutrophil cytosolic factor 1, which is also a biomarker of neutrophil differentiation) are elevated in both cases, and 2) the antioxidant N-acetyl-L-cysteine restores basal expression of galectin-3 following oxidant exposure. In addition, our results suggest that the regulation of oxidative stress-sensitive galectins involves DNA hypomethylation mechanisms. Expression of galectin-3 and galectin-12 exhibits an opposite relationship to the expression of HMOX1/NCF1, suggesting a stimulatory and inhibitory role of these galectins in neutrophil-like differentiation of HL-60 cells. We also show that the inhibition of galectins reduces the growth rate of HL-60 cells, and facilitates their neutrophil-like differentiation. Collectively, our findings indicate that the process of cellular differentiation implicates, in part, oxidative stress-sensitive galectins, which further highlights a biological significance of galectin network remodeling in cells.