A mechanistic study of cellular photodestruction with 5-aminolaevulinic acid-induced porphyrin.
A mechanistic study of cellular photodestruction with 5-aminolaevulinic acid-induced porphyrin.
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用5-氨基烯酸酸诱导的卟啉的细胞光铸造的机械研究。
DOI：
10.1038/bjc.1994.244
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发表时间：
1994-07
影响因子：
8.8
通讯作者：
Hasan, T.
中科院分区：
文献类型：
--
作者：
Iinuma, S.;Farshi, S. S.;Ortel, B.;Hasan, T.
5-本实验研究了氨基乙酰丙酸（ALA）诱导的5种恶性肿瘤细胞和2种正常细胞卟啉生物合成及光毒性。细胞内的原卟啉IX（PpIX）含量定量提取和荧光光谱。细胞PpIX含量并不总是与细胞增殖率的细胞系的倍增时间测量。还研究了PpIX的细胞外排。在膀胱癌细胞系中，观察到的快速外排没有被维拉帕米（一种P-糖蛋白外排泵的抑制剂）阻断。这些数据支持这样的观点，即细胞PpIX积累是一个动态过程，其由PpIX从细胞的流出和血红素生物合成途径中的酶活性决定。去铁胺（desferal），PpIX生物合成的调节剂，增强ALA诱导的细胞PpIX含量显着在所有癌细胞系，但不是在非恶性细胞系。增强的PpIX细胞积累归因于亚铁螯合酶活性的抑制，该酶负责将PpIX转化为血红素。用514.5 nm的氩离子激光照射后，通过“MTT试验”测定PpIX介导的细胞光破坏。细胞PpIX含量似乎存在“阈值”效应;合成低于140 ng/mg-1蛋白质的细胞表现出非常小的光毒性损伤，而具有大于140 ng PpIX/mg-1蛋白质的细胞系[校正]表现出一致的光毒性反应。在经历光毒性损伤的细胞系中，PpIX细胞含量和ALA诱导的光毒性之间没有严格的相关性。Desferal可增强PpIX含量和光毒性效应。ALA处理的细胞的荧光显微镜显示线粒体中PpIX的显著积累（罗丹明123共染色）。用ALA诱导的PpIX光敏化的细胞的电子显微照片证实了光毒性损伤的主要部位也是线粒体，其显示在照射后几分钟内线粒体肿胀，而其他亚细胞器似乎不受影响。线粒体的修复或进一步破坏是能量密度和细胞类型依赖性的。本研究的数据表明，ALA诱导的PpIX在肿瘤中蓄积增加的基础是代谢过程和药代动力学的各个方面的组合，并且恶性肿瘤的光破坏的功效不仅由PpIX合成的速率决定，而且还由特定的细胞和组织特征决定。
5-Aminolaevulinic acid (ALA)-induced porphyrin biosynthesis and phototoxicity in vitro was investigated in five malignant and two normal cell lines. Intracellular protoporphyrin IX (PpIX) content was quantified by extraction and fluorescence spectroscopy. Cellular PpIX content did not always correlate with cell proliferation rate as measured by the doubling times of cell lines. Cellular efflux of PpIX was also investigated. In a bladder carcinoma cell line, the observed rapid efflux was not blocked by verapamil, an inhibitor of the P-glycoprotein efflux pump. These data support the view that cellular PpIX accumulation is a dynamic process that is determined by both the efflux of PpIX from the cells and enzyme activities in the haem biosynthesis pathway. Desferrioxamine (desferal), a modulator of PpIX biosynthesis, enhanced ALA-induced cellular PpIX content significantly in all carcinoma cell lines but not in non-malignant cell lines. The enhanced PpIX cellular accumulation is attributed to inhibition of ferrochelatase activity, the enzyme responsible for the conversion of PpIX to haem. PpIX-mediated cellular photodestruction following irradiation with an argon ion laser at 514.5 nm was determined by the 'MTT assay'. There appeared to be a 'threshold' effect of cellular PpIX content; cells that synthesised less than 140 ng/mg-1 protein exhibited very little phototoxic damage, while cell lines having greater than 140 ng PpIX/mg-1 protein [corrected] exhibited a consistent phototoxic response. Among the cell lines which did undergo phototoxic damage, there was not a strict correlation between PpIX cellular content and ALA-induced phototoxicity. Desferal enhanced the PpIX content and phototoxic effect in the responsive cells. Fluorescence microscopy of the ALA-treated cells revealed marked accumulation of PpIX in mitochondria (rhodamine 123 co-staining). That the primary site of phototoxic damage is also the mitochondria was confirmed by electron micrographs of cells photosensitised with ALA-induced PpIX, which showed swelling of mitochondria within minutes after irradiation while other suborganelles appeared to be unaffected. The repair or further destruction of the mitochondria was fluence and cell-type dependent. The data from this study suggest that the basis of increased ALA-induced PpIX accumulation in tumours is a combination of various aspects of the metabolic process and pharmacokinetics and that the efficacy of photodestruction of malignancy will be determined not only by the rate of PpIX synthesis but also by specific cellular and tissue characteristics.
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DOI：
10.1073/pnas.88.4.1580
发表时间：
1991-02-01
影响因子：
11.1
作者：
BACHOR, R;SHEA, CR;HASAN, T
通讯作者：
HASAN, T
影响因子：
4.1
作者：
BONKOVSKY, HL;HEALEY, JF;SINCLAIR, JF
通讯作者：
SINCLAIR, JF
影响因子：
8.8
作者：
Loh, C S;MacRobert, A J;Bedwell, J;Regula, J;Krasner, N;Bown, S G
通讯作者：
Bown, S G
DOI：
10.1016/1011-1344(90)85083-9
发表时间：
1990-06-01
影响因子：
5.4
作者：
KENNEDY, JC;POTTIER, RH;PROSS, DC
通讯作者：
PROSS, DC
影响因子：
8.8
作者：
LOH, CS;BEDWELL, J;BOWN, SG
通讯作者：
BOWN, SG