Glucocorticoid resistance induced by ANXA5 overexpression in B-cell acute lymphoblastic leukemia.

Development of chemo‑resistance is ultimately responsible for treatment failure and relapse in B-cell acute lymphoblastic leukemia (B-ALL). However, the mechanism underlying glucocorticoid (GC) resistance remains unclear. This study was performed to identify GC resistance-related genes using the transcriptome chip from the GEO database, and preliminarily analyze drug resistance mechanism in B-ALL. Here, we found that ANXA5 expression was upregulated in B-ALL cells and high-level ANXA5 was associated with dexamethasone (DEX) resistance. Then, small interfering RNA (siRNA) was designed to silence ANXA5 expression in the B-ALL cell lines, and the apoptotic rate of cells treated with DEX was detected by flow cytometry. As a result, cell apoptosis was dramatically promoted in B-ALL cells following silencing of ANXA5 and DEX administration versus that in ANXA5-silenced alone or DEX-treated alone cells. It was further found that down-regulation of ANXA5 in B-ALL cells significantly increased the relative amount of cleaved Caspase 3 and Caspase 9 induced by DEX. Collectively, inhibition of ANXA5 gene expression may represent a novel method to restore the sensitivity of treatment-resistant B-ALL tumors to GC-induced cell death, which is of important clinical significance to overcome drug resistance associated with B-ALL.