AIM:To explore the promoting action of chloroquine on the anti-proliferation effect of dexametha-sone on acute lymphoblastic leukemia cells .METHODS:CCK-8 assay was used to assess the viability of the dexametha-sone-resistant human acute lymphoblastic leukemia CEM-C1 cell line treated with the combination of chloroquine and dexa-methasone .Western blotting , quantitative real-time PCR and LysoTracker Red staining were utilized to examine the mecha-nism.RESULTS:Combination of chloroquine and dexamethasone significantly inhibited the proliferation of CEM -C1 cells compared with control group (P<0.01).The combination of chloroquine and dexamethasone increased the abundance of glucocorticoid receptor and inhibited lysosomal function , while lysosomal inhibitor bafilomycin A 1 also increased glucocorti-coid signaling .CONCLUSION:Dexamethasone combined with chloroquine triggers an anti-proliferation effect on CEM-C1 cells via a lysosome-mediated pathway .