GSE137359
Chidamide triggers BTG1-mediated autophagy and reverses the chemotherapy resistance in the relapsed/refractory B cell lymphoma
Rituximab/chemotherapy relapsed and refractory B cell lymphoma patients have a poor overall prognosis, and it is urgent to develop novel drugs for improving the therapies of these patients. A new oral histone deacetylase inhibitor, chidamide shows anti-tumor activity by activating the pro-apoptosis pathway in some other hematological malignancies, suggesting its potential application to the relapsed and refractory B cell lymphoma. In this study, we examined the therapeutic effects of chidamide on the cell and mouse models of the rituximab/chemotherapy resistant B cell lymphoma, as well as the primary B cell lymphoma cells. In Raji-4RH and RL-4RH cells, the rituximab/chemotherapy resistant B cell lymphoma cell lines (RRCL), chidamide treatment induced growth inhibition and G0/G1 cell cycle arrest, which were associated with E2F1/2 inactivation and CDK2 degradation. The primary B cell lymphoma cells from Rituximab/chemotherapy relapsed and refractory patients were also very sensitive to chidamide treatment. Interestingly, chidamide triggered the cell death via the autophagy pathway instead of the activation of apoptosis in Raji-4RH and RL-4RH cells, likely due to the lack of the pro-apoptotic proteins in these resistant cells. In the RNA-seq and chromatin immunoprecipitation (ChIP) analysis, we identified BTG1 and FOXO1 as the direct target genes of chidamide, which control the autophagy and cell cycle respectively in RRCL treated with chidamide. Moreover, the combination of chidamide with the chemotherapy drug Cisplatin sensitized the RRCL to growth inhibition in a synergistic manner. Chidamide-Cisplatin combination significantly reduced the tumor burden of a mouse lymphoma model established with engraftment of RRCL. Taken together, our studies provides a theoretic and mechanistic basis for further evaluation of the chidamide-based clinical trial for rituximab/chemotherapy relapsed and refractory B cell lymphoma patients. Overall design: Raji and Raji-4RH were treated with DMSO or chidamide (3µM) for 24h and then RNA was subjected to RNA-seq analysis.