Bromodomain-containing Protein 4 (BRD4), an ‘epigenetic reader’, regulates chromatin structure and gene expression via recognizing and binding acetylated lysine in histones. BRD4 has become a therapeutic target for cancers because it promotes the expression of the tumor genes, such as c-Myc, NF-κB, and Bcl-2. In this study, a new series of 3-methyl-1H-indazole derivatives were designed via virtual screening and structure-based optimization. All compounds were synthesized and evaluated for their inhibitory activities to BRD4-BD1 and their antiproliferative effects in cancer cell lines. Among them, several compounds (such as 9d, 9u and 9w) exhibited strong BRD4-BD1 affinities and inhibition activities, and potently suppressed MV4;11 cancer cell line proliferation. Among them, compound 9d showed excellent selectivity for BRD4 and effectively suppressed c-Myc, the downstream protein of BRD4. This study provided new lead compounds for further biological evaluation on BRD4.

含溴结构域的蛋白质 4 (BRD4) 是一种“表观遗传阅读器”，通过识别和结合组蛋白中的乙酰化赖氨酸来调节染色质结构和基因表达。BRD4 已成为癌症的治疗靶点，因为它促进了 c-Myc、NF-κB 和 Bcl-2 等肿瘤基因的表达。在这项研究中，通过虚拟筛选和基于结构的优化设计了一系列新的 3-甲基-1 H-吲唑衍生物。合成所有化合物并评估它们对 BRD4-BD1 的抑制活性及其在癌细胞系中的抗增殖作用。其中，几种化合物（如9d、9u和9w) 表现出强烈的 BRD4-BD1 亲和力和抑制活性，并有效抑制 MV4;11 癌细胞系增殖。其中，化合物9d对BRD4表现出优异的选择性，并有效抑制了BRD4下游蛋白c-Myc。该研究为BRD4的进一步生物学评价提供了新的先导化合物。