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

Radiosensitizing Effect of Tirapazamine-Gold Nanoparticle Compound on Human Hepatoma HepG2 Cells

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.