Pivotal roles of peptide transporter PEPT1 and ATP-binding cassette (ABC) transporter ABCG2 in 5-aminolevulinic acid (ALA)-based photocytotoxicity of gastric cancer cells in vitro
Pivotal roles of peptide transporter PEPT1 and ATP-binding cassette (ABC) transporter ABCG2 in 5-aminolevulinic acid (ALA)-based photocytotoxicity of gastric cancer cells in vitro
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DOI：
10.1016/j.pdpdt.2011.12.004
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发表时间：
2012-09-01
影响因子：
3.3
通讯作者：
Ogura, Shun-ichiro
中科院分区：
文献类型：
--
作者：
Hagiya, Yuichiro;Endo, Yoshio;Ogura, Shun-ichiro
背景：最近，基于5-氨基乙酰丙酸的光动力疗法（ALA- pdt）被广泛应用于癌症治疗中，这是因为在给药ALA后，光敏性原卟啉IX （PpIX）在肿瘤特异性积累。在本研究中，我们将重点关注卟啉生物合成途径中涉及的基因，旨在探索可预测ALA-PDT疗效的生物标志物。方法：采用5株人胃癌细胞，测定ala对人胃癌细胞的光毒性。用荧光分光光度法定量测定ala诱导的PpIX在癌细胞中的产生。为了研究PEPT1和ABCG2在ALA-PDT敏感性中的潜在作用，建立了过表达PEPT1的稳定细胞系，并使用了ABCG2特异性siRNA。结果：3株细胞株具有光敏性，2株细胞株具有抗ala光毒性。基于ala的光细胞毒性被发现与细胞内PpIX水平密切相关，这表明参与ala诱导PpIX产生的某些酶和/或转运体是关键的决定因素。我们发现肽转运体PEPT1 （ALA内流转运体）的高表达和atp结合盒转运体ABCG2（卟啉外流转运体）的低表达决定了ALA诱导的PpIX产生和细胞光敏性。结论：PEPT1和ABCG2在体外调节细胞内PpIX水平和决定ala光毒性对胃癌细胞的作用中起关键作用。评价PEPT1和ABCG2基因的表达水平有助于预测ALA-PDT的疗效。这些特异的引物是预测ALA-PDT光敏性的实用和有用的生物标志物。(C) 2011 Elsevier B.V.版权所有
Background: Recently, 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) is being widely used in cancer therapy owing to the tumor-specific accumulation of photosensitizing protoporphyrin IX (PpIX) after the administration of ALA. In the present study, by focusing on genes involved in the porphyrin biosynthesis pathway, we aimed to explore biomarkers that are predictive for the efficacy of ALA-PDT.Methods: We used five lines of human gastric cancer cells to measure the ALA-based photocytotoxicity. ALA-induced production of PpIX in cancer cells was quantified by fluorescence spectrophotometry. To examine the potential involvement of PEPT1 and ABCG2 in the ALA-PDT sensitivity, stable cell lines overexpressing PEPT1 were established and ABCG2-specific siRNA used.Results: We observed that three cell lines were photosensitive, whereas the other two cell lines were resistant to ALA-based photocytotoxicity. The ALA-based photocytotoxicity was found to be well correlated with intracellular PpIX levels, which suggests that certain enzymes and/or transporters involved in ALA-induced PpIX production are critical determinants. We found that high expression of the peptide transporter PEPT1 (ALA influx transporter) and low expression of the ATP-binding cassette transporter ABCG2 (porphyrin efflux transporter) determined ALA-induced PpIX production and cellular photosensitivity in vitro.Conclusion: PEPT1 and ABCG2 are key players in regulating intracellular PpIX levels and determining the efficacy of ALA-based photocytotoxicity against gastric cancer cells in vitro. Evaluation of the expression levels of PEPT1 and ABCG2 genes could be useful to predict the efficacy of ALA-PDT. Primers specific to those target genes are practical and useful biomarkers for predicting the photo-sensitivity to ALA-PDT. (C) 2011 Elsevier B.V. All rights reserved.