EPZ5676

EPZ5676 is a novel, highly potent and selective DOT1L histone methyltransferase inhibitor with a K_i value of less than 80pM and an IC₅₀ of 0.8nM against DOT1L, showing selectivity that is 37,000-fold higher than against other protein methyltransferases^[1-2]. EPZ5676 inhibits H3K79 methylation and the expression of MLL fusion target genes. EPZ5676 is used in research related to mixed-lineage leukemia (MLL-rearranged leukemia) ^[3-4].

In vitro, EPZ5676 (1μM) was used to treat estrogen receptor-positive/HER2-negative breast cancer cells (MCF7) and estrogen receptor-negative/HER2-positive cells (SKBR3) for 15 days. EPZ5676 significantly inhibited the levels of mono-, di-, and trimethylation of histone H3K79, effectively suppressed colony formation in both breast cancer cell lines, induced cell cycle G1 phase arrest and apoptosis, while also activating the interferon signaling pathway and upregulating HLA class I molecule expression^[5]. EPZ5676 (0-3μM) was also used to treat HeLa cells, Molm-13 cells, and MV4-11 cells for 72 hours. EPZ5676 resulted in significant inhibition of histone H3K79 dimethylation levels (IC₅₀=7nM), HoxA9 promoter activity (IC₅₀=52nM), and proliferation of MLL-rearranged leukemia cells (IC₅₀=15nM)^[6].

In vivo, in a P. acnes/LPS-induced fulminant hepatitis model, EPZ5676 (35mg/kg/day) was administered intraperitoneally to C57BL/6 mice (starting from day 0 after infection, once every two days, for a total of four times). EPZ5676 significantly improved mouse survival, alleviated liver injury and immune cell infiltration, and enhanced the immunosuppressive function of myeloid-derived suppressor cells (MDSCs)^[7]. In a TNBC xenograft model, EPZ5676 (50mg/kg) was administered intraperitoneally to tumor-bearing (MDA-MB-468 cells) NSG mice (once every other day, for a total of six times). EPZ5676 significantly reduced the frequency of tumor-initiating cells, inhibited tumor growth and metastasis, and decreased the proportion of ALDH1+ cancer stem cells^[8].

References:
[1] Daigle SR, Olhava EJ, Therkelsen CA, et al. Potent inhibition of DOT1L as treatment of MLL-fusion leukemia. Blood. 2013 Aug 8;122(6):1017-25.
[2] Choi HJ, Nguyen MT, Kim B, et al. DOT1L as a Therapeutic Target: Insights into Epigenetic Regulation and Cancer Treatment. Biomol Ther (Seoul). 2025 Nov 1;33(6):924-933.
[3] Annesley CE, Brown P. Novel agents for the treatment of childhood acute leukemia. Ther Adv Hematol. 2015 Apr;6(2):61-79.
[4] Stein EM, Tallman MS. Mixed lineage rearranged leukaemia: pathogenesis and targeting DOT1L. Curr Opin Hematol. 2015 Mar;22(2):92-6.
[5] Yoshido A, Ishiguro K, Kitajima H, et al. DOT1L inhibition exerts the anti-tumor effect by activating interferon signaling in breast cancer cells. Clin Epigenetics. 2025 Nov 26;17(1):201.
[6] Möbitz H, Machauer R, Holzer P, et al. Discovery of Potent, Selective, and Structurally Novel Dot1L Inhibitors by a Fragment Linking Approach. ACS Med Chem Lett. 2017 Feb 14;8(3):338-343.
[7] Yang W, Yu H, Huang J, et al. Inhibition of Dot1L Alleviates Fulminant Hepatitis Through Myeloid-Derived Suppressor Cells. Cell Mol Gastroenterol Hepatol. 2021;12(1):81-98.
[8] Kurani H, Razavipour SF, Harikumar KB, et al. DOT1L Is a Novel Cancer Stem Cell Target for Triple-Negative Breast Cancer. Clin Cancer Res. 2022 May 2;28(9):1948-1965.

EPZ5676是一种新型的、高效的、选择性DOT1L组蛋白甲基转移酶抑制剂，K_i值小于80pM，对DOT1L的IC₅₀为0.8nM，选择性比作用于其他多种蛋白甲基转移酶高37000倍^[1-2]。EPZ5676能够抑制H3K79甲基化和MLL融合靶基因的表达。EPZ5676可用于混合系白血病（MLL-rearranged leukemia）的相关研究^[3-4]。

在体外，EPZ5676（1μM）处理雌激素受体阳性/HER2阴性乳腺癌细胞（MCF7）和雌激素受体阴性/HER2阳性细胞（SKBR3）15天，EPZ5676显著抑制组蛋白H3K79的单甲基化、二甲基化和三甲基化水平，并有效抑制两种乳腺癌细胞的集落形成，诱导细胞周期G1期阻滞和凋亡，同时激活干扰素信号通路及上调HLA I类分子表达^[5]。EPZ5676（0-3μM）处理HeLa细胞、Molm-13细胞及MV4-11细胞72小时，EPZ5676显著抑制组蛋白H3K79二甲基化水平（IC₅₀=7nM）、HoxA9启动子活性（IC₅₀=52nM）及MLL重排白血病细胞增殖（IC₅₀=15nM）^[6]。

在体内，在P. acnes/LPS诱导的暴发性肝炎模型中，EPZ5676（35mg/kg/day）腹腔注射处理C57BL/6小鼠（从感染后第0天开始，每2天一次，共4次），EPZ5676显著提高小鼠生存率，减轻肝脏损伤和免疫细胞浸润，并增强髓源性抑制细胞（MDSC）的免疫抑制功能^[7]。在TNBC异种移植模型中，EPZ5676（50mg/kg）腹腔注射处理荷瘤（MDA-MB-468细胞）NSG小鼠（隔日一次，共6次），EPZ5676显著降低肿瘤起始细胞频率，抑制肿瘤生长和转移，并减少ALDH1⁺肿瘤干细胞比例^[8]。