Department of Health Technology & Informatics, The Hong Kong Polytechnic University, Hong Kong.
Photodiagnosis Photodyn Ther. 2011 Sep;8(3):254-63. doi: 10.1016/j.pdpdt.2010.12.002. Epub 2011 Feb 3.
The purpose of this study was to investigate the photoefficacies of protoporphyrin IX (PpIX) generated by drug precursor 5-aminolevulinic acid (ALA) and its hexyl ester (H-ALA) on two human non-small lung carcinoma cell lines (H460/Bcl-2 and H460/neo).
Drug uptake and the photoefficacies of PpIX were measured by flow cytometry and MTT assay; while the mode of cell death and alternation of signal transduction pathways were studied with 4',6-diamidino-2-phenylindole (DAPI) staining and Western blot analysis, respectively.
The flow cytometric analysis of H-ALA (5μM) uptake revealed optimal fluorescent intensity at 8h incubation, while ALA (0.5mM) was still far from saturation. The LD(30) of H-ALA-PDT was 30μM, 2J/cm(2), while the LD(30) of ALA-PDT was 3mM, 2J/cm(2). The dark toxicities mediated by both pro-drug H-ALA and ALA were negligible. By DAPI staining, apoptotic cell death was observed. In addition, by Western blot analysis, H-ALA- and ALA-mediated PDT initiated apoptotic cell death via the up-regulation and activation of p38 mitogen activated protein kinase (MAPK), the stress-activated c-jun N-terminal kinases (JNK) and ERK.
These results suggested that H-ALA and ALA mediated PDT displayed similar photocytotoxicities towards the two non-small lung cancer cells. Our present study also demonstrates H-ALA or ALA mediated PDT in H460 cells are closely related to the activation of p38 MAPK and JNK signalling pathway.
本研究旨在探讨 5-氨基酮戊酸（ALA）及其己酯（H-ALA）前体药物生成的原卟啉 IX（PpIX）对两种人非小细胞肺癌细胞系（H460/Bcl-2 和 H460/neo）的光效。
通过流式细胞术和 MTT 测定法测量药物摄取和 PpIX 的光效；通过 4'，6-二脒基-2-苯基吲哚（DAPI）染色和 Western blot 分析分别研究细胞死亡方式和信号转导途径的改变。
H-ALA（5μM）摄取的流式细胞分析显示 8 小时孵育时荧光强度最佳，而 ALA（0.5mM）仍远未饱和。H-ALA-PDT 的 LD(30)为 30μM，2J/cm(2)，而 ALA-PDT 的 LD(30)为 3mM，2J/cm(2)。两种前体药物 H-ALA 和 ALA 介导的暗毒性可以忽略不计。通过 DAPI 染色观察到凋亡细胞死亡。此外，通过 Western blot 分析，H-ALA 和 ALA 介导的 PDT 通过上调和激活丝裂原活化蛋白激酶（MAPK）p38、应激激活的 c-jun N 末端激酶（JNK）和 ERK 引发凋亡细胞死亡。
这些结果表明，H-ALA 和 ALA 介导的 PDT 对两种非小细胞肺癌细胞显示出相似的光细胞毒性。我们的研究还表明，H460 细胞中 H-ALA 或 ALA 介导的 PDT 与 p38 MAPK 和 JNK 信号通路的激活密切相关。
