Du Hong-Yan, Bay Boon-Huat, Olivo Malini
Department of Anatomy, National University of Singapore, Singapore.
Int J Oncol. 2003 May;22(5):1019-24.
The use of photodynamic therapy (PDT) for the treatment of recurrent and residual nasopharyngeal carcinoma (NPC) has been encouraging. To determine the potential of hypericin as a PDT tool in the treatment of NPC, we investigated the effect of hypericin-mediated PDT on subcutaneously implanted NPC/HK1 tumor cells and the relationship between the biodistribution of hypercin and photodynamic effects. The plasma hypericin level increased rapidly and reached its peak concentration at 1 h after injection. The uptake of hypercin in tumor tissue was maximal 6 h after hypericin administration, at which time the drug concentration in the circulation was low. The efficacy of hypericin-mediated PDT was maximal when light irradiation was performed at 6 h after hypericin administration. Tumor relative regression percentage (RRP) induced by PDT at 1-h interval was comparable to that at 6-h interval, whereas light treatment performed at other time intervals induced less tumor RRP, albeit significant when compared to the control group. Hypericin appears to be an effective photosensitizer for the treatment of NPC. It is likely that hypericin-mediated PDT induces both vascular damage and direct tumor cell killing, thereby bringing about tumor necrosis and shrinkage.
光动力疗法（PDT）用于治疗复发性和残留性鼻咽癌（NPC）的效果令人鼓舞。为了确定金丝桃素作为一种光动力疗法工具在治疗鼻咽癌中的潜力，我们研究了金丝桃素介导的光动力疗法对皮下植入的NPC/HK1肿瘤细胞的影响，以及金丝桃素的生物分布与光动力效应之间的关系。注射后血浆中金丝桃素水平迅速升高，并在1小时后达到峰值浓度。金丝桃素给药6小时后，肿瘤组织对其摄取量最大，此时循环中的药物浓度较低。当在金丝桃素给药后6小时进行光照时，金丝桃素介导的光动力疗法效果最佳。光动力疗法在1小时间隔诱导的肿瘤相对消退率（RRP）与6小时间隔时相当，而在其他时间间隔进行光照治疗诱导的肿瘤RRP较低，尽管与对照组相比仍有显著差异。金丝桃素似乎是一种治疗鼻咽癌的有效光敏剂。金丝桃素介导的光动力疗法可能同时诱导血管损伤和直接杀伤肿瘤细胞，从而导致肿瘤坏死和缩小。
