Apoptosis is a particular process that leads to the programmed cell death, and it has been a potentially therapeutic target of
cancer. In this study, we evaluated the possible apoptotic effects of
glycolic acid on human
leukemia cell line (HL-60) in vitro. The morphological changes, cell viability, apoptosis induction, and
caspase-3 activity were measured by phase microscopy, flow cytometry, and Western blot analysis. Morphological changes including shrinkage of cells were clearly demonstrated in HL-60 cells treated with increasing concentrations of
glycolic acid. Cell viability was significantly affected by
glycolic acid treatment in a dose- and time-dependent manner. In comparison to the control group,
glycolic acid treatment had a profound effect in the induction of apoptosis by flow cytometric assays. In the cell cycle analysis,
glycolic acid caused the increased percentage of cells in G2/M phase and the decreased expression of the
cyclin A and
cyclin B1, suggesting the induction of G2/M arrest of cell cycle by
glycolic acid. Moreover,
glycolic acid treatment promoted
caspase-9 and -3 activity in a dose-dependent manner, but caspse-8 activity was not affected during the same process.
Glycolic acid co-administrated with broad-spectrum
caspase inhibitor,
z-VAD-fmk,
caspase-3 activity was blunted and apoptosis was also markedly blocked in HL-60 cells. In conclusion,
glycolic acid-induced apoptosis in HL-60 cells may be through the activation of
caspase-3. Future studies focusing on cell signaling and
biological significance of
glycolic acid-induced apoptosis would lead to exploring the mechanisms of chemotherapeutic potency of
glycolic acid in human
cancers.