Photodynamic therapy with 5-aminolevulinic acid: A new diagnostic, therapeutic, and surgical aid for neuroblastoma

Toshihiko Watanabe, Yoshiaki Nishio, Yuki Yamamoto, Takahiro Shimizu, Xiao Kang Li, Hajime Okita, Tatsuo Kuroda

Research output: Contribution to journalArticlepeer-review

Abstract

Background: 5-Aminolevulinic acid (ALA)-based photodynamic therapy (PDT) is widely used in cancer therapy because of the tumor-specific accumulation of photosensitizing protoporphyrin IX (PpIX). We aimed to assess the susceptibility of human neuroblastoma cell lines to ALA-PDT and determine the mechanism of PDT. Methods: We used four human neuroblastoma cell lines (GOTO, NB9, IMR32, and NB1) and a gastric cancer cell line (MKN45) as a positive control. Cells were treated with increasing concentrations of ALA, and the ALA-induced production of PpIX in tumor cells was quantified using fluorescence spectrophotometry. PDT photocytotoxicity was measured by exposing the cells to a 630-nm irradiation for 10 min, and apoptotic cells stained with phosphatidylserine (PS) and propidium iodide (PI) were detected through flow cytometry. Results: ALA cytotoxicity was not observed in any cell line. The intracellular concentration of PpIX increased in an ALA dose-dependent manner, and intracellular fluorescence of PpIX increased in a time-dependent manner. The viability of NB-1 cells treated with 250 μM 5-ALA rapidly decreased to 5%. Photocytotoxicity was observed in the following order: NB1, IMR32, NB-9, and GOTO. Photocytotoxicity was positively correlated with intracellular PpIX concentrations. PS+/PI- cells increased up to 21% after 12 h, and PS+/PI+ cells accounted for 35% of all cells after 24 h, which suggests that ALA-PDT induced apoptotic cell death. Conclusion: This study shows that neuroblastoma cell lines were susceptible to 5-ALA-PDT, resulting in persistent apoptotic cell death. Levels of evidence: N/A for basic study.

Original languageEnglish
Pages (from-to)1281-1285
Number of pages5
JournalJournal of Pediatric Surgery
Volume57
Issue number7
DOIs
Publication statusPublished - 2022 Jul

Keywords

  • 5-ALA
  • 5-aminolevulinic acid
  • Children
  • Neuroblastoma
  • PDT
  • Photodynamic therapy

ASJC Scopus subject areas

  • Surgery
  • Pediatrics, Perinatology, and Child Health

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