The effect of a novel photodynamic therapy with glycoconjugated fullerene and ultraviolet A-1 irradiation against bladder cancer cells

[目的]光动力疗法(PDT)是一种利用光吸收分子和可见光照射，在O^2存在的情况下产生细胞毒性活性氧，从而导致肿瘤消融的抗癌方法。葡萄糖共轭富勒烯(C60-Glu)是一种新的光敏剂，可在恶性肿瘤细胞中蓄积(图1)。此前，我们报道了紫外线A-1(UVA-1)辐射诱导的细胞凋亡发生在肿瘤细胞而不是正常细胞中。在这项研究中，我们研究了一种新型的光动力疗法，结合C60-Glu和UVA-1照射对膀胱癌细胞的作用。[材料和方法]富勒烯被认为是一类新的碳分子。1985年发现的富勒烯由60个碳原子组成，呈足球状结构排列。虽然富勒烯是一种著名的自由基清除剂，但它在紫外线A-1区(340-400 nm)具有激发波长，并在激发时有效地产生ROS。而且，富勒烯在黑暗中无毒。本研究选用三株人膀胱癌细胞株(T24、5637和RT4)。我们用WST-1比色法或流式细胞仪分析这些光细胞毒效应。接下来，我们在体内植入BALB/c-nu/nu雄性小鼠体内，分析不处理或PDT对肿瘤生长的影响。[结果与讨论]C60-GUL和单纯UVA-1照射均能观察到C60-GUL和UVA-1照射对所有膀胱癌细胞株的细胞毒作用和细胞凋亡的影响。但通过这些联合治疗，我们观察到了显著的光细胞毒效应和细胞凋亡。在体内，该PDT对肿瘤生长有抑制作用。这些研究表明，C60-Glu和UVA-1联合PDT是一种新的膀胱癌治疗方法。

【Purpose】Photodynamic therapy(PDT) is an anticancer approach utilizing a light-absoring molecule and visible light irradiation to generate, in the presence of O^2, cytotoxic reactive oxygen species, which cause tumor ablation. Glycoconjugated fullerene (C60-glu) is a new photosensitizer which accumulates in malignant cells(Fig.1). Previously, we report that ultraviolet A-1(UVA-1) irradiation induced apoptosis occurs in a malignant cells rather than a normal cells. In this study, we investigated the effect of a novel PDT with C60-Glu and UVA-1 irradiation against bladder cancer cells. 【Material and Methods】Fullerene is considered a new class of carbon molecules. Fullerene discovered in 1985 is composed of 60 carbon atoms arranged in a soccer ball-like structure. Although fullerene is a well-known radical scavenger, it has excitation wavelengths in the ultraviolet A-1 region (340-400nm) and generates ROS effectively upon excitation. And, fullerene is not toxic in the dark. Three human bladder cancer cell lines (T24, 5637 and RT4) were used in this study. We analyzed these photocytotoxic effects by WST-1 assay or flow cytometric analysis. Next in vivo, we implanted in BALB/c-nu/nu male mice, and analyze the tumor growth by no treatment or PDT. 【Results and Discussion】We were able to observe the cytotoxic effect and apoptosis in all bladder cancer cell lines treated with only C60-gul or simple UVA-1 irradiation. But by these combination therapy, we observed a significant photocytotoxic effect and apoptosis. In vivo, this PDT suppressed the tumor growth. These studies indicated that PDT with C60-glu and UVA-1 was a new choice as a bladder cancer therapy.