替拉扎明-金纳米粒子复合物对人肝癌HepG2细胞的辐射增敏效应研究

Key words: 
• tirapazamine /
• gold nanoparticles /
• human hepatoma HepG2 cell /
• radiosensitizing effect

Abstract: 

将替拉扎明(TPZ) 与聚乙二醇包被的金纳米粒子(PEG-GNP) 偶联，形成新型替拉扎明-金纳米粒子复合物(TPZ-PEG-GNP)。利用酶标仪获得TPZ-PEG-GNP 在200  800 nm范围内的紫外-可见光吸收光谱；采用电感耦合等离子体质谱(ICP-MS) 检测TPZ-PEG-GNP 在人肝癌HepG2 细胞中的摄取量；MTT法检测TPZ-PEG-GNP 对HepG2 细胞增殖活力的影响；香豆素-3-羧酸(3-CCA) 羟自由基探针检测X 射线和碳离子辐照下TPZ-PEG-GNP 在水中的羟自由基辐射增强效应；克隆形成法检测X 射线及碳离子辐照下TPZ-PEG-GNP 对HepG2 细胞的辐射增敏效应。实验结果表明：TPZ偶联到PEG-GNP 上形成的TPZPEG-GNP 对HepG2 细胞基本无毒；在有氧条件下，TPZ-PEG-GNP 在水中显著增加X射线和碳离子辐照下的羟自由基产额，对HepG2 细胞具有明显的辐射增敏效应；在X 射线及碳离子辐照下10% 存活水平时，TPZ-PEG-GNP 对HepG2 细胞的辐射增敏比分别为1.23 和1.47。

Tirapazamine (TPZ) was conjugated with polyethylene-glycol-coated gold nanoparticles (PEGGNP) to form new tirapazamine-gold nanoparticle compounds (TPZ-PEG-GNP). UV-vis absorption spectrum of TPZ-PEG-GNP at wavelengths from 200 to 800 nm was measured with a microplate reader. The kinetics
of TPZ-PEG-GNP uptake by human hepatoma  HepG2 cells was determined using inductively coupled plasma mass spectrometry (ICP-MS). To evaluate the cellular toxicity of TPZ-PEG-GNP, the effect of TPZ-PEG-GNP on HepG2 cell viability was examined by means of the MTT method. Moreover, the radiation enhancement effect of hydroxide radical production in ultra-pure water with TPZ-PEG-GNP exposed to X-rays and carbon ions was investigated using coumarin-3-carboxylic acid (3-CCA) as the free radical probe. More importantly, the radiosensitizing effect of TPZ-PEG-GNP on HepG2 cells irradiated with X-rays and carbon ions was assessed with the clonogenic survival assay. Our experimental results indicate that TPZ-PEG-GNP had nearly no toxicity to HepG2 cells. The yield of hydroxide radicals in ultra-pure water in the presence of TPZ-PEG-GNP after exposure to X-rays and carbon ions increased obviously and an obvious radiosensitizing effect of TPZ-PEG-GNP on HepG2 cells was observed under aerobic conditions. The radiation enhancement ratio of TPZ-PEG-GNP on HepG2 cells exposed to X-rays and carbon ions was 1.23 and 1.47 at 10% survival level.