Chidamide represses MYC expression and might improve survival for patients with double expressor lymphoma

Double expressor lymphoma (DEL), characterized by high expressions of both MYC and BCL-2, displays poor prognosis after current therapies. The HDAC inhibitor chidamide has been approved for treatment of T cell lymphoma, but its efficacy on B cell lymphoma is unclear. Here, by combining inhibition screening and transcriptomic analyses, we found that the sensitivity of B lymphoma cells to chidamide was positively correlated with the expression levels of MYC. Chidamide treatment reduced MYC protein levels and repressed MYC pathway in B lymphoma cells with high MYC expressions. Ectopic expression of MYC in chidamide-insensitive B lymphoma cells increased their response to chidamide. Thus, we proposed that adding chidamide into R-CHOP (CR-CHOP) might be effective for DEL, and retrospectively analyzed 185 DEL patients treated in West China Hospital. 80% of patients showed response to CR-CHOP treatment. In the median follow-up of 42 months, CR-CHOP significantly improve the survival for DEL patients with R-IPI ≤2. Totally 35 patients underwent autologous stem cell transplantation (ASCT) in remission and demonstrated a trend for better survival. Combining CR-CHOP with ASCT resulted in the most superior PFS and OS above all. For response patients, CR-CHOP reduced relapse with better PFS than R-CHOP-like regimens with or without ASCT. Taken together, our data indicated that chidamide repressed the MYC pathway in B lymphoma and is potentially efficacious to treat DEL.