Regulation of 5-Aminolevulinic Acid-Mediated Protoporphyrin IX Accumulation in Human Urothelial Carcinomas
Regulation of 5-Aminolevulinic Acid-Mediated Protoporphyrin IX Accumulation in Human Urothelial Carcinomas
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DOI：
10.1159/000245896
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发表时间：
2009-01-01
期刊：
影响因子：
5
通讯作者：
Sasaki, Junzo
中科院分区：
文献类型：
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作者：
Inoue, Keiji;Karashima, Takashi;Sasaki, Junzo
目的：本研究旨在阐明5-氨基乙酰丙酸（ALA）介导的人尿路上皮癌（UC）中原卟啉IX（PpIX）合成的调控机制，从而提高ALA光动力学诊断和治疗的准确性。实验设计：在与0.5-5 mM ALA孵育1-5小时后，通过使用荧光显微镜和流式细胞术技术的荧光分析来分析培养的UC细胞中的PpIX积累。结果如下：与非癌细胞相比，UC细胞中ALA介导的PpIX荧光增加，并且PpIX荧光的强度随时间而增加。内源性PpIX荧光的分布主要与线粒体一致，然后在孵育期间在细胞中的特定核周区域增加。UC细胞中ALA介导的PpIX合成被细胞膜β-转运蛋白抑制剂β-丙氨酸和线粒体氧化磷酸化解偶联剂羰基氰化物对三氟甲氧基苯腙抑制。与此相反，ALA介导的PpIX积累增加去铁胺，铁螯合剂，锰和一氧化氮，这是有助于PpIX代谢抑制亚铁螯合酶活性，产生一氧化氮生成试剂NOC-18。如上所述，人UC细胞中ALA介导的PpIX合成受ALA摄取、ALA转化为PpIX和积累的PpIX代谢为血红素的过程调节。结论：这表明，使用少量ALA，亚铁螯合酶的抑制增加了UC细胞中PpIX的积累，从而导致光动力学诊断和治疗的临床实用性提高。版权所有（C）2009 S. Karger AG，巴塞尔
Purpose: The purpose of this study was to clarify the regulatory mechanism of protoporphyrin IX (PpIX) synthesis mediated by 5-aminolevulinic acid (ALA) in human urothelial carcinoma (UC), leading to improved accuracy in photodynamic diagnosis and therapy using ALA. Experimental Design: PpIX accumulation in cultured UC cells after incubation for 1-5 h with 0.5-5 mM ALA was analyzed by fluorescence analysis using fluorescence microscopy and flow cytometry technique. Results: PpIX fluorescence mediated by ALA was increased, and the intensity of PpIX fluorescence was time-dependently increased in UC cells compared to noncancerous cells. The distribution of endogenous PpIX fluorescence primarily coincided with mitochondria, and then increased at a specific perinuclear region in the cells during the time of incubation. The ALA-mediated PpIX synthesis in UC cells was suppressed by beta-alanine, an inhibitor of beta-transporters of cell membrane, and carbonyl cyanide p -trifluoromethoxy-phenyl hydrazone, an uncoupler of mitochondrial oxidative phosphorylation. In contrast, the ALA-mediated PpIX accumulation was increased by deferoxamine, an iron chelator, manganese and nitric oxide, which is contributed to PpIX metabolism by inhibiting ferrochelatase activity, generated by a nitric oxide-generating reagent NOC-18. As observed above, ALA-mediated PpIX synthesis in human UC cells was regulated by the process of ALA uptake, ALA conversion to PpIX and metabolism of accumulated PpIX to heme. Conclusions: This shows that the suppression of ferrochelatase increased PpIX accumulation in UC cells using small amount of ALA, thus leading to an improved clinical practicability of photodynamic diagnosis and therapy. Copyright (C) 2009 S. Karger AG, Basel