SRP327566 PRJNA744996 GSE179792 The synergistic anti-tumor activity of EZH2 inhibitor SHR2554 and HDAC inhibitor chidamide through ORC1 reduction of DNA replication process in diffuse large B cell lymphoma Background: Upregulation of H3K27me3 induced by EZH2 overexpression or somatic heterozygous mutations were implicated in lymphomagenesis. It has been demonstrated that several EZH2-target agents have notable therapeutic effects in EZH2-mutant B-cell lymphoma patients. Here we present a novel highly selective EZH2 inhibitor SHR2554 and possible combination strategy in diffuse large B cell lymphoma (DLBCL); Methods: Cell proliferation, cycle and apoptosis were analyzed by Cell Titer-Glo Luminescent Cell Viability Assay and flow cytometry. Western Blot was used to detect the regulatory protease in related signaling pathways and RNA-seq was conducted to assess transcriptome changes. Finally, CDX and PDX models were used to evaluate the synergistic anti-tumor effects of the combination in vivo; Results: The novel EZH2 inhibitor SHR2554 could inhibited proliferation, induced G1 phase arrest in EZH2-mutant DLBCL cell lines. The combination of EZH2 inhibitor SHR2554 with histone deacetylase (HDAC) inhibitor chidamide (hereafter referred as HBI8000) exerted synergistic anti-proliferative activity in vitro and in vivo. Gene expression profile analysis revealed dramatic inhibition of DNA replication process in combined treatment; Conclusions: SHR2554, a potent highly selective small molecule inhibitor of EZH2, inhibited EZH2-mutant DLBCL more significantly in vitro and in vivo. The combination of HDAC inhibitor HBI8000 with EZH2 inhibitor SHR2554 exhibited dramatically anti-tumor activity in both mutant and wild-type DLBCL, which may become potential therapeutic modality for the treatment of DLBCL patients. Overall design: RNA sequencing in 2 DLBCL cell lines with SHR2554 and/or HBI8000 treatment . GSE179792 pubmed 34503063