Basics of the photodynamic therapy (PDT) of bladder carcinoma using Tetrahydroporphyrin-Tetratosylate (THPTS)

膀胱癌是德国第三常见的肿瘤。估计死亡率为6.4%。膀胱癌的治疗取决于肿瘤的分级和侵袭性。手术干预是经尿道浅表肿瘤切除术（TURB）和根治性膀胱切除术，以防晚期，侵袭期。为了支持TURB，已经建立了使用氨基乙酰丙酸盐或六聚氨基乙酰丙酸盐的光动力学诊断（PDD）。PDD改善了视觉上不可疑的浅表尿路上皮肿瘤的发现和切除。这些物质也被用于光动力疗法（PDT）。然而，由于激发光对组织的穿透不足以及高辐照引起的毒副作用，结果令人失望。四氢卟啉四atosylate （tetrahydroporphyin - tetratosylate， THPTS）是首个具有光物理性质的光敏剂，在760nm红外波段具有高吸收率，可能适用于PDT治疗浅表性和浸润性肿瘤。成功建立THPTS-PDT的先决条件是在动物模型中证明毒理学安全性和有效性，并阐明体外作用方式。我们想用大鼠膀胱癌模型和培养的膀胱癌细胞系来解决这些问题。AY27大鼠膀胱癌细胞可诱导大鼠膀胱发生膀胱癌。已确定的膀胱肿瘤将采用THPTS-PDT治疗。THPTS-PDT的安全性将在动物模型中通过剂量范围测定实验进行检验，包括评估对健康膀胱组织的可能损伤。治疗效果将通过组织学检查来验证。利用体外培养的大鼠细胞、人正常膀胱细胞和膀胱癌细胞株，研究THPTS-PDT的作用模式。我们将应用共聚焦显微镜、免疫细胞化学、细胞活力和凋亡测定以及基因表达分析。

Bladder carcinoma is the third most frequent tumour in Germany. The estimated mortality rate is 6.4%. The therapy of the bladder carcinoma depends on the tumour grade and invasiveness. Surgical interventions are transurethral resection of superficial tumours (TURB) and radical cystectomy in case of advanced, invasive stages. In support of the TURB, photodynamic diagnosis (PDD) using aminolevulinate or hexaminolevulinate has been established. PDD has improved the detection and resection of visually unsuspicious superficial urothelial tumours. Those substances have also been used for photodynamic therapy (PDT). However, due to insufficient tissue penetration of excitation light and due to toxic side effects caused by high irradiation, the results were disappointing.Tetrahydroporphyrin-Tetratosylate (THPTS) is the first photosensitizer with photo-physical properties and high absorption at infrared wavelength of 760nm, which might be suitable to treat superficial and infiltrating tumours by PDT. Prerequisite for successful establishment of THPTS-PDT is the proof of toxicological safety and efficiency in an animal model and the elucidation of the mode of action in vitro. We want to address those questions using a rat bladder carcinoma model and cultured bladder carcinoma cell lines. Bladder carcinoma will be induced in the rat bladder by instillation of AY27 rat bladder carcinoma cells. The established bladder tumours will be treated by THPTS-PDT. The safety of THPTS-PDT will be examined in animal model by dose range finding experiments including evaluation of possible injury of healthy bladder tissue. Treatment efficiency will be verified by histological examination. The mode of action of THPTS-PDT will be examined in vitro using cultured rat cells, human normal bladder cells and bladder carcinoma cell lines. We will apply confocal microscopy, immunocytochemistry, cell vitality and apoptosis assays, and gene expression analysis.