Objective: To synthesize compounds based on imidazo-fused heterocycles and evaluate their anti-tumor activity against breast cancer.
Methods: The compounds 1a-1e, 2a and 2b were synthesized by aerobic copper-catalyzed halocyclization of methyl N-heteroaromatics with aliphatic amines; 3a and 3b were generated by sonogashira reaction and Suzuki reaction, respectively; the compounds 4a-4c were obtained by Buchwald-Hartwig reaction of the corresponding amines and 1e. The effects of these compounds against breast cancer cells and their nephrotoxicity were determined using MTT assay. Annexin VFITC/PI apoptosis detection kit was used to assess the apoptosis-inducing effects of these compounds in breast cancer cells. With normal saline as the control, the safety and anti-tumor activity of the compound 2a (daily dose of 10 mg/kg for 14 days) was tested in a mouse model bearing human breast cancer xenografts.
Results: The compounds 2a, 4a, 4b and 4c all showed obvious anti-tumor activities. Among these compounds, 2a showed the most potent anti-tumor effect against breast cancer cells with an IC50 of 9.77 ± 2.32 μmol/L, similar to that of cisplatin (IC50=8.96 ± 2.35 μmol/L); 2a also showed a slightly lower nephrotoxicity than cisplatin, and their CC50 was 10.79±0.87 μmol/L and 8.45±0.68 μmol/L, respectively. 2a obviously promoted apoptosis of breast cancer cells in vitro and caused a moderate suppression of the breast cancer growth in the tumor-bearing mouse models without producing serious adverse effects.
Conclusions: Four compounds synthesized based on imidazo-fused heterocycles have anti-tumor activities against breast cancer. The compound 2a is capable of dose-dependently promoting apoptosis of breast cancer cells in vitro and has a good safety and a moderate efficacy for suppressing tumor growth in mouse models bearing human breast cancer xenografts.
目的: 合成以咪唑并杂环为母体的化合物，并评价抗乳腺癌活性。
方法: 利用甲基N-杂环化合物与脂肪胺的有氧铜催化的卤环化反应合成1a-1e、2a和2b；通过sonogashira偶联反应合成3a；使用suzuki偶联反应合成3b；相应胺与1e的BuchwaldHartwig偶联分别得到4a-4c。通过MTT法测定目标化合物的抗乳腺癌活性和肾毒性。通过Annexin V-FITC/PI试剂盒检测目标化合物对乳腺癌细胞的凋亡诱导作用。通过裸鼠异种移植模型评价2a的体内安全性和有效性：利用SPSS产生随机数字将裸鼠随机分为治疗组与对照组，每组6只。治疗组腹腔注射2a的生理盐水溶液[10 mg/（kg·d）]；对照组注射等量生理盐水，持续14 d。实验结束时处死小鼠，取出肿瘤并测量，计算体积。
结果: 通过活性筛选发现4个活性较好的化合物2a、4a、4b和4c。其中2a活性最好，IC50值是9.77±2.32 μmol/L，接近阳性对照药物顺铂（IC50=8.96±2.35 μmol/L），且肾毒性略小于顺铂（2a的CC50为10.79±0.87 μmol/L，顺铂的CC50为8.45±0.68 μmol/L）。2a促进乳腺癌细胞发生凋亡。2a在10 mg/（kg·d）的剂量下对小鼠体内肿瘤生长有一定抑制作用，且未引起严重不良反应。
结论: 合成了12个咪唑并杂环化合物，有3个结构新颖的化合物。发现4个抗癌活性较好的化合物。化合物2a以浓度依赖的方式促进sk-br-3细胞凋亡，从而引起细胞死亡。2a在体内具有安全性和一定的抗乳腺癌活性。
Keywords: anti-cancer; apoptosis; breast cancer; heterocycle; imidazole.