Characteristics of boningmycin induced cellular senescence of human tumor cells

Cellular senescence is one of the important steps against tumor.  This study was to observe the characteristics of boningmycin induced senescence of human tumor cells.  MTT method and clone formation assay were used to detect the growth-inhibitory effect.  Cellular senescence was detected with senescence-associated beta-galactosidase staining.  Cell cycle distribution and accumulation of intracellular reactive oxygen species (ROS) were analyzed with flow cytometry.  Protein expression was detected by Western blotting.  The results showed that the growth-inhibitory effect of boningmycin was obviously stronger on human oral epithelial    carcinoma KB cells than that on non-small cell lung cancer A549 cells.  Comparison to the similar action of doxorubicin, that boningmycin induced the features of cellular senescence in both cell lines, its due to the arrest at G₂/M phase and an increase of ROS level.  The molecular senescence marker P21 increased significantly  after boningmycin treatment at a dosage of 0.1 μmol·L⁻¹, whereas a higher concentration of it induced apoptosis.  The results indicated that cellular senescence induced by boningmycin was one of its mechanisms in tumor   suppression.