Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, #04-01, Biopolis, Singapore 138669, Singapore.
Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, #04-01, Biopolis, Singapore 138669, Singapore; Research and Development Center for Innovative Pharmaceuticals, Guangxi Botanic Garden of Medicinal Plants, Chinese Academy of Medical Sciences, 189 Changgang Road, Nanning, Guangxi 530023, China.
Biomaterials. 2014 Aug;35(26):7479-87. doi: 10.1016/j.biomaterials.2014.05.022. Epub 2014 Jun 6.
Hepatocellular carcinoma (HCC) is one of the most commonly diagnosed lethal cancers in the world. We previously showed two imidazolium salts (IBN-1 and IBN-9) with a moderate efficacy for HCC. Here we report a more potent imidazolium compound IBN-65 (1-benzyl-2-phenyl-3-(4-isopropyl)-benzyl-imidazolium chloride) and the associated mechanisms of action in a mouse model of HCC. The IC50 of this compound in various liver cancer cell lines was around 5 μm. IBN-65 dose-dependently arrested cell cycle at G1 phase and was associated with the down-regulation of the cyclin-dependent kinase-4, -6, cyclin D1, and cyclin E. In addition, IBN-65 induced apoptosis by down-regulating Survivin, Bcl-2 and up-regulating Bax, leading to sequential activation of Caspase-3, Caspase-9 and the cleavage of poly(ADP-ribose) polymerase (PARP). Dysregulation of the epidermal growth factor receptor (EGFR) signaling network has been frequently reported in HCC. We found that IBN-65 displayed a profound inhibitory effect on the EGFR/Raf/MEK/ERK signaling at the phosphorylation level. In Huh7 or Hep3B cells, pretreatment with IBN-65 attenuated EGF-induced phosphorylation of both EGFR and the downstream p44/42 MAPK. A siRNA knockdown of EGFR also proved that IBN-65 induced apoptosis mostly through inhibiting downstream EGFR pathway signaling, much less at the receptor level. Infrequent administration of IBN-65 (i.p., 5 mg/kg once weekly for four weeks) to mice bearing the Huh7 cells significantly reduced the tumor volume by 65% without affecting the body weight. Critically, many of the anti-tumor signaling features observed in the HCC cell lines were recaptured in the xenografted tissues. Thus, the metal-free imidazolium compound IBN-65 could be a potential candidate towards therapeutic development for HCC.
肝细胞癌 (HCC) 是世界上最常见的致命癌症之一。我们之前曾报道过两种咪唑盐 (IBN-1 和 IBN-9)，它们对 HCC 具有中等疗效。在这里，我们报告了一种更有效的咪唑化合物 IBN-65（1-苄基-2-苯基-3-(4-异丙基)-苄基-咪唑𬭩氯化物）及其在 HCC 小鼠模型中的作用机制。该化合物在各种肝癌细胞系中的 IC50 约为 5 µm。IBN-65 剂量依赖性地将细胞周期阻滞在 G1 期，并与细胞周期蛋白依赖性激酶-4、-6、细胞周期蛋白 D1 和细胞周期蛋白 E 的下调有关。此外，IBN-65 通过下调 Survivin、Bcl-2 和上调 Bax 诱导细胞凋亡，导致 Caspase-3、Caspase-9 的顺序激活和多聚（ADP-核糖）聚合酶（PARP）的裂解。表皮生长因子受体 (EGFR) 信号网络的失调在 HCC 中经常被报道。我们发现 IBN-65 对 EGFR/Raf/MEK/ERK 信号在磷酸化水平上表现出显著的抑制作用。在 Huh7 或 Hep3B 细胞中，IBN-65 预处理可减弱 EGF 诱导的 EGFR 和下游 p44/42 MAPK 的磷酸化。EGFR 的 siRNA 敲低也证明 IBN-65 诱导的细胞凋亡主要是通过抑制下游 EGFR 途径信号，而不是受体水平。以 5mg/kg 的剂量每周腹腔注射 IBN-65（i.p.）一次，连续四周，可使荷瘤小鼠的肿瘤体积减少 65%，而不影响体重。重要的是，在异种移植组织中重新捕获了在 HCC 细胞系中观察到的许多抗肿瘤信号特征。因此，无金属咪唑化合物 IBN-65 可能成为治疗 HCC 的潜在候选药物。
