Discovery of potent 2,4-difluoro-linker poly(ADP-ribose) polymerase 1 inhibitors with enhanced water solubility and in vivo anticancer efficacy
作者:Wen-hua Chen、Shan-shan Song、Ming-hui Qi、Xia-juan Huan、Ying-qing Wang、Hualiang Jiang、Jian Ding、Guo-bin Ren、Ze-hong Miao、Jian Li
DOI:10.1038/aps.2017.104
日期:2017.11
Poly (ADP-ribose) polymerase 1 (PARP1) is overexpressed in a variety of cancers, especially in breast and ovarian cancers; tumor cells that are deficient in breast cancer gene 1/2 (BRCA1/2) are highly sensitive to PARP1 inhibition. In this study, we identified a series of 2,4-difluorophenyl-linker analogs (15â55) derived from olaparib as novel PARP1 inhibitors. Four potent analogs 17, 43, 47, and 50 (IC50=2.2â4.4 nmol/L) effectively inhibited the proliferation of Chinese hamster lung fibroblast V-C8 cells (IC50=3.2â37.6 nmol/L) in vitro, and showed specificity toward BRCA-deficient cells (SI=40â510). The corresponding hydrochloride salts 56 and 57 (based on 43 and 47) were highly water soluble in pH=1.0 buffered salt solutions (1628.2 μg/mL, 2652.5 μg/mL). In a BRCA1-mutated xenograft model, oral administration of compound 56 (30 mg·kg-1·d-1, for 21 d) exhibited more prominent tumor growth inhibition (96.6%) compared with the same dose of olaparib (56.3%); in a BRCA2-mutated xenograft model, oral administration of analog 43 (10 mg·kg-1·d-1, for 28 d) significantly inhibited tumor growth (69.0%) and had no negative effects on the body weights. Additionally, compound 56 exhibited good oral bioavailability (F=32.2%), similar to that of olaparib (F=45.4%). Furthermore, the free base 43 of the hydrochloride salt 56 exhibited minimal hERG inhibition activity (IC50=6.64 μmol/L). Collectively, these data demonstrate that compound 56 may be an excellent drug candidate for the treatment of cancer, particularly BRCA-deficient tumors.
聚(ADP-核糖)聚合酶1(PARP1)在一系列癌症中过度表达,尤其是在乳腺癌和卵巢癌中;而缺乏乳腺癌基因1/2(BRCA1/2)的肿瘤细胞对PARP1抑制高度敏感。本研究以奥拉帕利为先导物,设计合成了一系列对2-氟-4-氟苯基连结体结构进行改造的PARP1抑制剂15-55,其中活性较好的4个化合物17、43、47、50(IC50=2.2-4.4 nmol/L)对仓鼠肺成纤维细胞V-C8的增殖具有较高抑制活性(IC50=3.2-37.6 nmol/L),并且对BRCA缺陷细胞更具选择性,选择性指数(SI)高达40-510。其中43、47经盐酸成盐后的化合物56、57在pH=1.0的盐溶液中具有非常好的溶解性(分别为1628.2 μg/mL和2652.5 μg/mL)。在BRCA1突变的异种移植瘤模型中,经口给予56(30 mg·kg-1·d-1,21 d)显示了较奥拉帕利(56.3%)更显著(96.6%)的肿瘤生长抑制作用;在BRCA2突变异种移植瘤模型中,43(10 mg·kg-1·d-1,28 d)显著抑制肿瘤生长(69.0%)且对小鼠体质量无负面影响。此外,56具有良好的口服生物利用度(32.2%),与奥拉帕利相当。此外,56的游离碱43表现出最小的hERG抑制活性。综上所述,56可能是治疗癌症,特别是BRCA缺陷型肿瘤的优秀候选药物。