MYCN-driven TCL is sensitive to EZH2 depletion and HDAC inhibition. (A) Dose-response curve for 24-hour treatment with the EZH2 degrader MS1943 on ex vivo cultured MYCN-driven TCL cells. (B) Dose-response curve for 24-hour treatment with the CDK1 inhibitor Ro-3306 on ex vivo cultured MYCN-driven TCL cells. (C) Annexin V staining of MYCN-driven TCL cells treated ex vivo for 8 hours with DMSO, 10 nM romidepsin, 5 μM Ro-3306, 5 μM MS1943, or a combination of these inhibitors. (D) Normalized counts for HDAC1, HDAC2, and HDAC3 from the PTCL cases from the Leuven cohort and the Kyoto cohort. (E) Representative ChIP-seq tracks for the Hdac1, Hdac2, and Hdac3 promoter regions showing binding of MYCN, Ezh2, Suz12, p300, and histone marks H3K4me3, H3K27ac, and H3K27me3 in MYCN-driven TCL. (F) Normalized expression levels of Hdac1, Hdac2, and Hdac3 in CD4 T cells and in MYCN-driven lymphoma cells. n.s., not significant. (G) Dose response curve for 24-hour treatment with the HDAC inhibitors romidepsin and belinostat on ex vivo cultured MYCN-driven TCL cells. (H) Dose-response curve for 48-hour treatment of RPMI-8402 cells with different HDAC inhibitors. (I) qRT-PCR analysis of MYCN and EZH2 target gene expression in MYCN-driven TCL cells treated ex vivo for 4 hours with 500 nM romidepsin. Data are represented as mean ± standard deviation. (J) qRT-PCR analysis of MYCN and EZH2 target gene expression in RPMI-8402 cells treated for 16 hours with HDAC inhibitors belinostat or romidepsin. (K) Dose response curve for 24-hour treatment with the EZH2 degrader MS1943 with or without simultaneous romidepsin treatment on ex vivo cultured MYCN-driven TCL cells. (L) Synergy matrix plot showing δ scores for ex vivo cultured MYCN-driven TCL cells treated with romidepsin + MS1943 (max zero interaction potential [ZIP] synergy score = maximal score for a specific dose combination; average ZIP synergy score = the average δ score for the whole range of concentrations shown in the synergy matrix). (M) Dose-response curve for 24-hour treatment with the CDK1 inhibitor Ro-3306 with or without simultaneous romidepsin treatment on ex vivo cultured MYCN-driven TCL cells. (N) Synergy matrix plot showing δ scores for ex vivo cultured MYCN-driven TCL cells treated with romidepsin + Ro-3306 (max ZIP synergy score = maximal score for a specific dose combination; average ZIP synergy score = the average δ score for the whole range of concentrations shown in the synergy matrix). (O) Viability of RPMI-8402 cells treated for 40 hours with the HDAC inhibitor romidepsin (Romi) (3 nM), the EZH2 degrader MS1943 (5 μM), the CDK1 inhibitor Ro3306 (5 μM), the EZH2 methyltransferase inhibitor tazemetostat (Taz) (5 μM), or a combination. See also supplemental Figure 6. ∗∗∗∗P < .0001, ∗∗∗P < .001, ∗∗P < .01, ∗P < .05.