HDAC inhibitor chidamide overcomes drug resistance in chronic myeloid leukemia with the T315i mutation through the Akt–autophagy pathway

Currently, therapy for Chronic Myeloid Leukemia (CML) patients with the T315I mutation is a major challenge in clinical practice due to its high degree of resistance to first- and second-generation Tyrosine Kinase Inhibitors (TKIs). Chidamide, a Histone Deacetylase Inhibitor (HDACi) drug, is currently used to treat peripheral T-cell lymphoma. In this study, we investigated the anti-leukemia effects of chidamide on the CML cell lines Ba/F3 P210 and Ba/F3 T315I and primary tumor cells from CML patients with the T315I mutation. The underlying mechanism was investigated, and we found that chidamide could inhibit Ba/F3 T315I cells at G0/G1 phase. Signaling pathway analysis showed that chidamide induced H3 acetylation, downregulated pAKT expression and upregulated pSTAT5 expression in Ba/F3 T315I cells. Additionally, we found that the antitumor effect of chidamide could be exerted by regulating the crosstalk between apoptosis and autophagy. When chidamide was used in combination with imatinib or nilotinib, the antitumor effects were enhanced compared with chidamide alone in Ba/F3 T315I and Ba/F3 P210 cells. Therefore, we conclude that chidamide may overcome T315I mutation-related drug resistance in CML patients and works efficiently if used in combination with TKIs.