Figure 3.

CXCR4 silencing reverses osteosarcoma doxorubicin resistance by inducing autophagic cell death. (A) LM8 (CXCR4 knockdown) and Dunn (CXCR4 overexpression) cells were pretreated with bafilomycin A1 (200 nM) and rapamycin (200 nM), respectively, for 6 h, and then treated with or without 0.2 µg/ml doxorubicin for 48 h. The expression levels of beclin 1, light chain 3B, cleaved caspase 3, caspase 3 and P-glycoprotein were determined by western blotting, and the protein bands were semi-quantified and subjected to statistical analysis. (B) Cell proliferation in each group was detected by Cell Counting Kit-8 assay. (C) The apoptosis ratios for each group (percentage of Annexin V⁺ cells) were determined by flow cytometry. ^*P<0.05, ^**P<0.01, ^***P<0.001, ^****P<0.0001. CXCR4, C-X-C motif chemokine receptor 4.