Hsp90 inhibition promotes AID degradation in inflammation-stimulated BCR-ABL1⁺ B-ALL cells through the proteasome pathway. (A) After treatment with LPS for 48 hours, AID and Hsp90 proteins in BCR-ABL1⁺ B-ALL cells were detected by immunoprecipitation (IP) with the anti-AID (top) or anti-Hsp90 (bottom) antibody, followed by the indicated western blotting antibody. (B) BCR-ABL1⁺ B-ALL cells were treated with LPS (25 µg/mL) and 17-DMAG (0, 0.5, 1, 2, and 3 µM) (top) or LPS (25 µg/mL) and novobiocin (0, 0.1, 0.3, 0.5, and 1 mM) (bottom) for 24 hours. AID and Hsp90 expressions were measured by western blotting. Actin was used as loading control for total protein. The protein levels were quantified by the ImageJ program and normalized to actin. (C) BCR-ABL1⁺ B-ALL cells were treated with LPS (25 µg/mL) and 17-DMAG (0 and 3 µM) (left) or LPS (25 µg/mL) and novobiocin (0 and 1 mM) (right) for 24 hours, followed by treatment with MG132 (0 and 10 µM) during the last 12 hours. Cells were harvested at indicated time points. The AID and Hsp90 protein levels were examined by western blotting. The protein levels were quantified by the ImageJ program and normalized to actin. (D-E) BCR-ABL1⁺ B-ALL cells were treated with LPS (25 µg/mL) and 17-DMAG (0, 0.5, 1, 2, and 3 µM) or LPS (25 µg/mL) and novobiocin (0, 0.1, 0.3, 0.5, and 1 mM). (D) Assessment of cell viability by CCK-8 assay at 24 and 48 hours following treatment. (E) Analysis of cell apoptosis by flow cytometry at 24 and 48 hours following treatment. The data are representative of at least 3 independent experiments. Error bars represent the mean ± standard error of the mean. *P < .05, **P < .01, ***P < .001. ns indicates no significant differences.