Role of Caspases and Reactive Oxygen Species in Rose Bengal-Induced Toxicity in Melanoma Cells

Document Type: Original Article


1 Assistant Professor of Pharmacology, Pharmacological Research Centre of Medicinal Plants, School of Medicine, MUMS, Mashhad, Iran

2 Professor of Immunology and Oncology, Newcastle Mater Hospital, Newcastle, NSW, Australia.


We have previously shown that Rose Bengal (RB) alone, not as a photosensitiser, could induce apoptotic- and non-apoptotic cell death in different melanoma cell lines. To clarify RB-induced toxicity mechanisms, role of caspases and reactive oxygen specious (ROS) were studied in melanoma cells.
Material and Methods
Human melanoma cell lines, Me 4405 and Sk-Mel-28 were cultured in DMEM medium. Cell viability was quantitated by MTT assay. Apoptotic cells were determined using PI staining of DNA fragmentation by flow cytometry (sub-G1 peak). Role of caspase were studied using the pan-caspase inhibitor, z-VAD-fmk. ROS was measured using DCF-DA by flow cytometry analysis.
This study showed that whilez-VAD-fmk completely inhibited apoptosis of melanoma inducedby tumor necrosis factor (TNF)-related apoptosis-inducing ligand(TRAIL), it only partiallyblocked RB-induced apoptosis in Me4405 and Sk-Mel-28 melanoma cell lines. RB also increased ROS production in melanoma cells but pretreatment with antioxidant -glutamylcysteinylglycine (GSH) could not decrease RB-induced toxicity.
Both caspase-dependent and -independent pathways were inducedby RB in melanoma cells. RB-induced generation of ROS does not playa significant role in RB-induced toxicity and it is independent of ROS production in melanoma cells.


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