Related Experiment Videos
Photodynamic inactivation with acridine orange on a multidrug-resistant mouse osteosarcoma cell line
K Kusuzaki1, G Minami, H Takeshita
1Department of Orthopaedic Surgery, Kyoto Prefectural University of Medicine, Kawaramachi Hirokoji, Kamigyo-ku, Kyoto 602-8566, Japan. kusu@basic.kpu-m.ac.jp
Abstract:
Overcoming multidrug resistance (MDR) is an urgent issue to improve the prognosis of osteosarcoma patients. In this study, we undertook to clarify the effect of photodynamic therapy (PDT) with acridine orange (AO) on the MDR mouse osteosarcoma (MOS / ADR1) cell line, by comparing the outcome with the effect on a chemosensitive osteosarcoma (MOS) cell line. Cultured cells of MOS and MOS / ADR1 cell lines were exposed to AO at various concentrations for various times, followed by long- or short-term (10 or 1 min) illumination with blue light (466.5 nm) for excitation. Living cells were counted by means of the trypan blue exclusion test. The results showed that AO rapidly bound to DNA, RNA and lysosomes of living MOS and MOS / ADR1 cells and also that most tumor cells in both cell lines died rapidly (viability ratio to untreated cells: 1/1000) within 48 h under conditions of continuous or 15-min flash exposure to AO at concentrations above 1.0 microg/ml plus 10-min illumination with blue light. Even after flash exposure to AO at concentrations above 1.0 microg/ml plus 1-min illumination, the viability of MOS/ADR1 cells decreased to a viability ratio of less than 1/ 1000 within 72 h. Based on these results, we concluded that AO with photo-excitation has a strong cytocidal effect, not only on chemosensitive mouse osteosarcoma cells, but also on MDR mouse osteosarcoma cells. These results suggested that photodynamic therapy with AO may be a new approach to treating MDR human osteosarcomas.
Insights
Photodynamic therapy (PDT) using acridine orange (AO) and blue light effectively kills both drug-sensitive and multidrug-resistant (MDR) osteosarcoma cells. This suggests PDT with AO could be a promising new treatment for MDR osteosarcoma.
Area of Science:
- Oncology
- Biochemistry
- Photobiology
Background:
- Multidrug resistance (MDR) significantly worsens osteosarcoma patient outcomes.
- Novel therapeutic strategies are urgently needed to overcome MDR in osteosarcoma.
Purpose of the Study:
- To investigate the efficacy of photodynamic therapy (PDT) using acridine orange (AO) against multidrug-resistant (MDR) mouse osteosarcoma (MOS/ADR1) cells.
- To compare the effects of AO-mediated PDT on MDR osteosarcoma cells versus chemosensitive osteosarcoma (MOS) cells.
Main Methods:
- Cultured MOS and MOS/ADR1 cells were treated with varying concentrations of AO and exposed to blue light (466.5 nm) for different durations (1 or 10 minutes).
- Cell viability was assessed using the trypan blue exclusion test.
- AO's cellular localization was observed, noting its binding to DNA, RNA, and lysosomes.
Main Results:
- Acridine orange demonstrated rapid binding to DNA, RNA, and lysosomes in both cell lines.
- High concentrations of AO (≥1.0 µg/ml) combined with 10-minute blue light illumination resulted in rapid cell death (viability < 1/1000) within 48 hours for both MOS and MOS/ADR1 cells.
- Even with a 1-minute illumination, AO-PDT significantly reduced MOS/ADR1 cell viability to less than 1/1000 within 72 hours.
Conclusions:
- Acridine orange-mediated photodynamic therapy exhibits potent cytocidal effects on both chemosensitive and multidrug-resistant osteosarcoma cells.
- AO-PDT presents a potential novel therapeutic approach for treating multidrug-resistant human osteosarcomas.