Kato Shinya, Yoshimura Tetsuro, Miwa Nobuhiko
Radioisotope Facilities for Medical Science, Advanced Science Research Promotion Center, Mie University, Edobashi 2-174, Tsu, Mie, 514-8507, Japan.
Department of Liposome Bioengineering, Graduate School of Engineering, Mie University, Kurimamachiya-cho 1577, Tsu, Mie, 514-8507, Japan.
J Nanosci Nanotechnol. 2018 Jun 1;18(6):3775-3786. doi: 10.1166/jnn.2018.15240.
The polyhydroxy small-gap fullerenes [C120O30(OH)30 · 30H2O · 25Na+: SGFs] were encapsulated in multilamellar liposomes (Lpsm) composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-dioleoyl-sn-glycero-3-phospho-l-serine (DOPS), which are designated as LpsmSGFs (DOPC/DOPS/SGFs = 35 mM:15 mM:246-445 μM, diameter = 141.2 nm, ζ-potential = -35.65 mV). Radiosensitization by LpsmSGFs under X-ray irradiation was evaluated on human melanoma HMV-II cells. On 7th day after X-ray irradiation, cell proliferation degree assessed by WST-8 decreased more markedly on cells pretreated with LpsmSGFs than Lpsm or free-SGFs. Fluorescent imaging of cells with Rhodamine123, dihydroethidium or anti-8-hydroxydeoxyguanosine antibody was monitored as an indicator for mitochondrial membrane potentials, intracellular superoxide anion radicals (O˙-2) or oxidative DNA-damages, respectively. After X-ray irradiation, LpsmSGFs obviously exhibited more augmented mitochondrial membrane potentials on perinuclear region of cells than Lpsm or free-SGFs. Without X-ray irradiation, superoxide anion radicals were found principally in the cytoplasm, but, when exposed to X-ray, they were found in cell nuclei associated with oxidative DNA-damages on cells pretreated with LpsmSGFs. Meanwhile, the oxidation-reduction potentials of SGFs aqueous solution increased by X-ray irradiation. These results suggest that LpsmSGFs-mediated generation of reactive oxygen species results in damages to cellular components such as mitochondria and DNA on cells, and thereby cell proliferation decreased. The LpsmSGFs has a potential as a pro-oxidative type radiosensitizer.
多羟基小间隙富勒烯[C120O30(OH)30·30H2O·25Na+：SGFs]被包裹在由1,2-二油酰基-sn-甘油-3-磷酸胆碱（DOPC）和1,2-二油酰基-sn-甘油-3-磷酸-L-丝氨酸（DOPS）组成的多层脂质体（Lpsm）中，这些被命名为LpsmSGFs（DOPC/DOPS/SGFs = 35 mM:15 mM:246 - 445 μM，直径 = 141.2 nm，ζ电位 = -35.65 mV）。在人黑色素瘤HMV-II细胞上评估了LpsmSGFs在X射线照射下的放射增敏作用。在X射线照射后第7天，用WST-8评估细胞增殖程度，结果显示，用LpsmSGFs预处理的细胞比用Lpsm或游离SGFs预处理的细胞增殖程度下降更明显。分别用罗丹明123、二氢乙锭或抗8-羟基脱氧鸟苷抗体对细胞进行荧光成像监测，作为线粒体膜电位、细胞内超氧阴离子自由基（O˙-2）或氧化性DNA损伤的指标。X射线照射后，LpsmSGFs在细胞的核周区域比Lpsm或游离SGFs明显表现出更强的线粒体膜电位增强。在没有X射线照射时，超氧阴离子自由基主要存在于细胞质中，但当暴露于X射线时，在用LpsmSGFs预处理的细胞中，它们出现在与氧化性DNA损伤相关的细胞核中。同时，X射线照射使SGFs水溶液的氧化还原电位升高。这些结果表明，LpsmSGFs介导的活性氧生成导致细胞成分如线粒体和DNA受损，从而细胞增殖减少。LpsmSGFs具有作为促氧化型放射增敏剂的潜力。
