- 作者：Yuichiro Hagiya ; Hideo Fukuhara ; Kentaro Matsumoto ; Yoshio Endo ; Motowo Nakajima ; Tohru Tanaka ; Ichiro Okura ; Atsushi Kurabayashi ; Mutsuo Furihata ; Keiji Inoue ; Taro Shuin ; Shun-ichiro Ogura
- 关键词：5-Aminolevulinic acid ; Protoporphyrin IX ; Photodynamic diagnosis ; Bladder cancer ; PEPT1 ; ABCG2
- 刊名：Photodiagnosis and Photodynamic Therapy
- 出版年：2013
- 出版时间：September, 2013
- 年：2013
- 卷：10
- 期：3
- 页码：288-295
- 全文大小：3217 K
Summary
Background
A detection method widely used of late in cancer surgery is 5-aminolevulinic acid-based photodynamic diagnosis (ALA-PDD), which relies on the tumor-specific accumulation of photosensitizing protoporphyrin IX (PpIX) after the administration of ALA. In this regard, we recently reported that peptide transporter PEPT1 and human ATP-binding cassette transporter ABCG2 are key players in regulating intracellular PpIX levels. In the present study, we re-evaluated in vivo the expression of genes involved in the porphyrin biosynthesis pathway.Methods
Using quantitative real-time (qRT)-PCR, we measured the mRNA levels in a clinical specimen of bladder cancer from a patient who had been subjected to ALA-PDD.
Results
We confirmed that PEPT1 and ABCG2 are major contributors to the regulation of tumor-specific PpIX accumulation. qRT-PCR analysis revealed a predominantly high level of PEPT1 mRNA and a very low level of ABCG2 mRNA in the bladder cancer, corresponding to the roles of these genes in vitro. These findings were further confirmed by immunohistochemical studies with PEPT1- and ABCG2-specific antibodies.
Conclusion
The induction of PEPT1 gene and the suppression of ABCG2 gene expression are among the key molecular mechanisms underlying tumor-specific PpIX accumulation after the administration of ALA in bladder cancer.