Objective       To investigate the mechanism and significance of pirarubicin in enhancing the autophagy of HeLa cells.        Methods       Trypan blue exclusion assay and CCK-8 assay were used to detect cell mortality and proliferation in HeLa cells treated with different doses of pirarubicin alone or combined with chloroquine (autophagy inhibitor). The effect of pirarubicin on autophagosome formation in HeLa cells transfected with GFP-LC3 plasmid was observed with fluorescence microscopy. Western blotting was used to determine the protein levels of autophagy markers microtuble-associated protein light chain 3-Ⅱ (LC3-Ⅱ)

and autophapy related 4B (ATG4B). After ATG4B was down-regulated with shRNA in HeLa cells

the effect of pirarubicin on killing HeLa cells in the presence of chloroquine was observed.        Results       Pirarubicin inhibited cell proliferation and induced cell death in a dose-dependent manner in HeLa cells (P0.05). Pirarubicin induced the formation of LC3-GFP puncta in HeLa cells

and increased the expression of LC3Ⅱand ATG4B markedly. Chloroquine enhanced pirarubicin-triggered cell death in HeLa cells (P0.05). Knockdown of ATG4B via shRNA suppressed pirarubicin-induced autophagy and increased pirarubicin-induced cell death in HeLa cells.        Conclusion       Pirarubicin induces cytoprotective autophagy in HeLa cells through up-regulating ATG4B.