A 366 is a selective G9a/GLP histone methyltransferase inhibitor that inhibits the activity of G9a (IC50=3.3nM) and GLP (IC50=38nM). A 366 suppresses H3K9me2 methylation and interferes with the binding of Spindlin1 to H3K4me3[1-2]. A 366 can be used in research related to leukemia, prostate cancer, and autism spectrum disorders[3-4].
In vitro, U2OS human osteosarcoma cells were treated with A 366 (10μM) in combination with phleomycin (0.5–1μM) or etoposide (100nM) for 0-180 minutes. A 366 significantly impaired DNA double-strand break repair, enhanced DNA damage accumulation, and synergistically induced tumor cell death[5]. Human monocytes, M1/M2 monocyte-derived macrophages, CD4+ T cells, and B cells were pretreated with A 366 (5–50μM) for 30 minutes, followed by incubation with different inducters for 24 hours to 5 days. A 366 attenuated the M2 polarization of macrophages; A 366 also significantly inhibited the proliferation of B cells, the formation of plasmablasts, and the release of immunoglobulins G and A[6].
In vivo, Balb/c nu/nu mice bearing OPM2 multiple myeloma xenografts were treated with A 366 alone (8mg/kg; i.p.; for 6 days) or in combination with decitabine (0.2mg/kg) for the final 3 days. A 366 significantly inhibited tumor growth in the xenograft model, and the combination therapy demonstrated a synergistic antitumor effect without causing significant toxicity[7]. Wistar rats were treated with A 366 (25mg/kg; a single intraperitoneal injection). A 366 significantly reduced the clonogenic capacity of bone marrow-derived mesenchymal stem cells (BM-MSCs), prolonged their population doubling time, increased their adipogenic differentiation potential, and decreased their osteogenic differentiation potential[8].
References:
[1] Reiner D, Seifert L, Deck C, et al. Epigenetics meets GPCR: inhibition of histone H3 methyltransferase (G9a) and histamine H3 receptor for Prader-Willi Syndrome. Sci Rep. 2020 Aug 11;10(1):13558.
[2] Wagner T, Greschik H, Burgahn T, et al. Identification of a small-molecule ligand of the epigenetic reader protein Spindlin1 via a versatile screening platform. Nucleic Acids Res. 2016 May 19;44(9):e88.
[3] Sweis RF, Pliushchev M, Brown PJ, et al. Discovery and development of potent and selective inhibitors of histone methyltransferase g9a. ACS Med Chem Lett. 2014 Jan 2;5(2):205-9.
[4] Pappano WN, Guo J, He Y, et al. The Histone Methyltransferase Inhibitor A-366 Uncovers a Role for G9a/GLP in the Epigenetics of Leukemia. PLoS One. 2015 Jul 6;10(7):e0131716.
[5] Agarwal P, Jackson SP. G9a inhibition potentiates the anti-tumour activity of DNA double-strand break inducing agents by impairing DNA repair independent of p53 status. Cancer Lett. 2016 Oct 1;380(2):467-475.
[6] Schiffmann S, Henke M, Weber F, et al. Immune-modulatory effects of Spindlin-1 inhibitors. Clin Exp Immunol. 2025 Jan 21;219(1):uxaf013.
[7] Nylund P, Garrido-Zabala B, Tziola SI, et al. Dual targeting of G9a and DNMTs induces antitumor effects in multiple myeloma. Blood Adv. 2025 Oct 14;9(19):4825-4841.
[8] Khanban H, Fattahi E, Talkhabi M. In vivo administration of G9a inhibitor A366 decreases osteogenic potential of bone marrow-derived mesenchymal stem cells. EXCLI J. 2019 Jun 3;18:300-309.
A 366是一种选择性的G9a/GLP组蛋白甲基转移酶抑制剂，可抑制G9a（IC50=3.3nM）和GLP（IC50=38nM）的活性。A 366可抑制H3K9me2甲基化并干扰Spindlin1与H3K4me3的结合[1-2]。A 366可用于白血病、前列腺癌和自闭症谱系障碍的相关研究[3-4]。
在体外，A 366（10μM）联合phleomycin（0.5–1μM）或etoposide（100nM）处理人骨肉瘤U2OS细胞0-180分钟。A 366显著损害DNA双链断裂修复，增强DNA损伤积累，并协同诱导肿瘤细胞死亡[5]。A 366（5–50μM）处理预处理人单核细胞、M1/M2型单核来源巨噬细胞、CD4+ T细胞及B细胞30分钟后，加入不同的诱导剂孵育细胞24小时至5天。A 366可减弱巨噬细胞的M2极化；A 366可显著抑制B细胞的增殖、浆母细胞形成以及免疫球蛋白G和A的释放[6]。
在体内，A 366（8mg/kg；腹腔注射；持续6天）单独处理携带OPM2多发骨髓瘤细胞的Balb/c nu/nu小鼠，或再联合decitabine（0.2mg/kg）处理3天。A 366在异种移植模型中显著抑制了肿瘤生长，联合疗法显示出协同抗肿瘤效应，且未引起明显毒性反应[7]。A 366（25mg/kg；单次腹腔注射）处理Wistar大鼠。A 366显著降低了骨髓间充质干细胞（BM-MSCs）的克隆形成能力，延长了BM-MSCs倍增时间，同时增加了BM-MSCs成脂分化潜能并降低了成骨分化潜能[8]。