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Updated: May 2, 2026
Cytotoxic Efficacy of Photodynamic Therapy in Osteosarcoma Cells In Vitro
Published on: March 18, 2014
Photodynamic action of methylene blue in osteosarcoma cells in vitro
Jiemin Guan1, Xiaoping Lai2, Xinna Wang3
1School of Chinese Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong; School of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, China.
Background:
Osteosarcoma is a common malignant bone tumor which threatens the life of young people worldwide. To explore alternative strategy for combating osteosarcoma, a light-emitting diode (LED) that activates methylene blue (MB) was used in the present study to investigate cell death of osteosarcoma-derived UMR106 cells.
Materials And Methods:
Photocytotoxicity in UMR106 cells was investigated 24h after photodynamic activation of MB using sulforhodamine B (SRB) assay and light microscopy. Apoptosis induction was observed 24h after photodynamic treatment using a confocal laser scanning microscopy (CLSM) with Hoechst 33342 staining. The change in mitochondrial membrane potential (MMP) was analyzed using a flow cytometry with rhodamine 123 staining.
Results:
MB under red light irradiation caused a drug-concentration (0-100μM) and light-dose (0-32J/cm(2)) dependent cytotoxicity in UMR106 cells. The SRB assay and light microscopy observed a significant decrease in the number of UMR106 cells attached to the bottom of culture well after LED light-activated MB (100μM, 32J/cm(2)). Nuclear shrinkage, chromatin condensation and fragmentation were found in the treated cells by nuclear staining. In addition, flow cytometry showed that the MMP in UMR106 cells was rapidly reduced by photo-activated MB (100μM, 32J/cm(2)).
Conclusion:
Photodynamic action of MB under LED irradiation could remarkably kill osteosarcoma cells and induce cell apoptosis as well as MMP collapse.
Insights
Photodynamic therapy using methylene blue (MB) and light-emitting diodes (LEDs) effectively kills osteosarcoma cells. This approach induces apoptosis and mitochondrial membrane potential collapse in cancer cells.
Area of Science:
- Biomedical Engineering
- Photomedicine
- Cancer Research
Background:
- Osteosarcoma is a prevalent and life-threatening bone cancer in young individuals.
- Current treatments for osteosarcoma have limitations, necessitating novel therapeutic strategies.
- Photodynamic therapy (PDT) presents a promising alternative for cancer treatment.
Purpose of the Study:
- To investigate the efficacy of methylene blue (MB) activated by light-emitting diodes (LEDs) in inducing cell death of osteosarcoma cells.
- To explore the mechanisms of cell death, including apoptosis and mitochondrial dysfunction, induced by MB-PDT.
Main Methods:
- Osteosarcoma UMR106 cells were treated with varying concentrations of MB and light doses.
- Cell viability was assessed using the sulforhodamine B (SRB) assay and light microscopy.
- Apoptosis was detected via Hoechst 33342 staining and confocal laser scanning microscopy (CLSM).
- Mitochondrial membrane potential (MMP) changes were analyzed by flow cytometry using rhodamine 123.
Main Results:
- MB-PDT demonstrated a dose-dependent cytotoxicity against UMR106 cells.
- Significant reduction in cell attachment and viability was observed after MB-PDT.
- Nuclear shrinkage, chromatin condensation, and fragmentation indicated apoptosis induction.
- MB-PDT led to a rapid collapse of MMP in osteosarcoma cells.
Conclusions:
- Photodynamic action of MB under LED irradiation is a potent strategy for osteosarcoma cell killing.
- MB-PDT effectively induces apoptosis and mitochondrial membrane potential collapse in osteosarcoma cells.
- This study highlights the potential of MB-PDT as an alternative treatment for osteosarcoma.
