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Enhancement of photodynamic antitumor effect with pro‐oxidant ascorbate
Author(s) -
Wei Yanchun,
Song Jiaxing,
Chen Qun,
Xing Da
Publication year - 2012
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/lsm.21157
Subject(s) - photodynamic therapy , singlet oxygen , reactive oxygen species , chemistry , vitamin c , photochemistry , metal ions in aqueous solution , toxicity , radical , superoxide , ascorbic acid , antioxidant , vitamin , chemiluminescence , oxygen , cancer research , pharmacology , ion , biochemistry , medicine , enzyme , organic chemistry , food science
Background and Objective Photodynamic therapy (PDT) is a treatment modality that utilizes photosensitizers activated by light to induce cell death via the formation of singlet oxygen and other free radicals. Although this method has its advantages for tumor treatment, it cannot be well performed for involving so many therapeutic parameters during use. Tumor recurrence is common due to insufficient treatment. Therefore, a supplemental or complemental treatment is necessary for PDT. Study Design/Materials and Methods L ‐ascorbate, commonly known as vitamin C, is an essential nutrient for humans. It is also a well‐established pro‐oxidant in the presence of certain transition metal ions. In our experiments, ascorbate was administered to tumor‐bearing mice by intraperitoneal injection (i.p.) for 10 days after they were treated with PDT. We hypothesize that this supplement may improve the therapeutic outcome by as a result of the reactions between ascrobate and the metal ions induced by PDT. Results The results demonstrate that PDT can cause Fe and Cu ions to be released from their protein complexes. The reactions between the ions and ascorbate resulted in a post‐PDT surge in reactive oxygen species (ROS) as demonstrated in vitro with chemiluminescence detection. This ultimately leads to enhanced tumor cell death and, thus, an improved treatment outcome. Conclusion Based on the results that PDT induces metal ion release and ascorbate reacts with the metal ions producing subsequent ROS, an internal related, complementary and strengthened tumor treatment is established by combination of both PDT and ascorbate, as a low‐toxicity and effective method. Lasers Surg. Med. 44:69–75, 2012. © 2012 Wiley Periodicals, Inc.