Department of Chemistry, National Chung Hsing University, No. 250, Kuo-Kuang Rd., Taichung 402, Taiwan.
Biomaterials. 2013 Jan;34(4):1204-12. doi: 10.1016/j.biomaterials.2012.08.044. Epub 2012 Oct 12.
Photodynamic therapy (PDT) is an innovative method for cancer treatment that involves the administration of a photosensitizing agent followed by exposure to visible light. An appreciable amount of a particular light source is a key to activate photosensitizers in PDT. However, the external excitation light source is a problem for clinical application because of the limitation of tissue-penetrating properties. Additionally, the wavelength of laser emission should match the absorption wavelength of each photosensitizer for efficient generation of reactive oxygen species and cell killing. In this study, Renilla luciferase-immobilized quantum dots-655 (QD-RLuc8) was used for bioluminescence resonance energy transfer (BRET)-mediated PDT to resolve these problems. The bioluminescent QD-RLuc8 conjugate exhibits self-illumination at 655 nm after coelenterazine addition, which can activate the photosensitizer, Foscan(®)-loaded micelles for PDT. Our results show that BRET-mediated PDT by QD-RLuc8 plus coelenterazine (20 μg/mL) successfully generated reactive oxygen species (40.8%), killed ~ 50% A549 cells at 2 μg/mL equivalent Foscan(®)in vitro and significantly delayed tumor growth in vivo due to cell apoptosis under TUNEL analysis without obvious weight loss. Based on immunohistochemical observations, the proliferating cell nuclear antigen (PCNA)-negative area of tumor sections after BRET-mediated PDT was obviously increased compared to the PDT-untreated groups without an external light source. We conclude that this nanotechnology-based PDT possesses several clinical benefits, such as overcoming light penetration issues and treating deeper lesions that are intractable by PDT alone.
光动力疗法（PDT）是一种创新的癌症治疗方法，涉及光敏剂的给药，然后暴露于可见光下。相当数量的特定光源是激活 PDT 中光敏剂的关键。然而，由于组织穿透特性的限制，外部激发光源是临床应用的一个问题。此外，激光发射的波长应与每种光敏剂的吸收波长相匹配，以有效地产生活性氧和细胞杀伤。在这项研究中，使用荧光素酶固定化量子点-655（QD-RLuc8）进行生物发光共振能量转移（BRET）介导的 PDT，以解决这些问题。生物发光 QD-RLuc8 缀合物在加入腔肠素后在 655nm 处自发光，可激活光敏剂，用于 PDT 的 Foscan（®）载药胶束。我们的结果表明，QD-RLuc8 加腔肠素（20μg/mL）通过 BRET 介导的 PDT 成功地产生了活性氧（40.8%），在体外以 2μg/mL 等效 Foscan（®）杀死了约 50%的 A549 细胞，并在体内由于 TUNEL 分析中的细胞凋亡而显著延迟了肿瘤生长，而没有明显的体重减轻。基于免疫组织化学观察，BRET 介导的 PDT 后肿瘤切片中增殖细胞核抗原（PCNA）阴性区域明显增加，与无外部光源的 PDT 未处理组相比。我们得出结论，这种基于纳米技术的 PDT 具有一些临床益处，例如克服光穿透问题和治疗单独 PDT 难以治疗的深部病变。
