title: Indocyanine green acts as a photosensitizer but not a radiosensitizer: combined chemo-, photo- and radiotherapy of DFW human melanoma cells.
abstract: This study aimed to evaluate the effects of indocyanine green as a sensitizer for both photodynamic and radiation therapy in the DFW human melanoma cell line. The cells were incubated with indocyanine green at different concentrations for 24 hours and then exposed in independent treatment groups to non-coherent light at different fluence rates and X-ray ionizing radiation at different dose rates. In addition, the combined effects of this chemo-, photo-, and radiotherapy were evaluated using the MTT assay. The results showed that indocyanine green had no significant cytotoxic effects at concentrations up to 100 microM. However, when the compound was used as a photosensitizer, it had a strong cytotoxic effect on cancer cells. No radiosensitizing activity was detected. Surprisingly, treatment with 50 microM indocyanine green in combination with 30 J/cm2 light and 4 Gy X-ray radiation reduced the percentage of viable cancer cells to 1.22%. The inclusion of the photosensitizer with the low dose of radiation and reduced light fluence rate therefore yielded the same treatment efficacy as more toxic, high-dose radiation and light therapies.
authors.affiliation: Department of Medical Physics, Research Center of Medical Physics, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Ameneh
authors.initials: A
authors.lastname: Sazgarnia
authors.affiliation: Department of Medical Physics, Research Center of Medical Physics, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Mohammad Hossein
authors.initials: MH
authors.lastname: Bahreyni-Toosi
authors.affiliation: Department of Medical Physics, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Ali Reza
authors.initials: AR
authors.lastname: Montazerabadi
authors.affiliation: Pharmaceutical Sciences Research Center, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran.
authors.forename: Amirhossein
authors.initials: A
authors.lastname: Ahmadi
mesh_terms: D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D006801:Humans; D007208:Indocyanine Green / Q000494:pharmacology*; D008545:Melanoma / Q000473:pathology / Q000628:therapy*; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000494:pharmacology*; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*
chemical_list: D017319:Photosensitizing Agents; D011838:Radiation-Sensitizing Agents; D007208:Indocyanine Green