Riboflavin acetate induces apoptosis in squamous carcinoma cells after photodynamic therapy.
Several research efforts have been focused on finding newer and more efficient photosensitizers for photodynamic therapy (PDT). Although, it was demonstrated that riboflavin is an efficient photosensitizer for PDT, the effect of its ester derivate, riboflavin 2',3',4',5'-tetraacetate (RFTA), which has higher cellular uptake, has not been well defined. To evaluate the cell death generated by applying RFTA as the photosensitizer in PDT in a human cancer cell line of squamous carcinoma (SCC-13), these cells were incubated with riboflavin and its ester derivate, RFTA followed by irradiation with different blue light doses. Cell viability was evaluated using neutral red uptake assay and cell death was evaluated using transmission electron microscopy, TUNEL assay and annexin V-PE/7AAD double staining. The expression of caspase-3, Bax, Bcl-2, ERK 1/2 and p38(MAPK) was evaluated by Western blotting and generation of intracellular ROS and changes in anion superoxide levels were analyzed using 2',7'-dichlorofluorescein-diacetate and dihydroethidium dye, respectively. RFTA-PDT generated a decrease in cancer cell viability in a light dose-response. Treated SCC-13 cells exhibited chromatin condensation, formation of apoptotic bodies, increases in TUNEL-positive cells, phosphatidylserine externalization and decreased procaspase-3 and Bcl-2 protein expression and increment of ERK 1/2 phosphorylation. Moreover, trolox abolished the effect of PDT on cell viability linking the increase in intracellular ROS levels with the cell death observed, whereas that the pre-treatment with MEK inhibitor did not induce changes in SCC-13 cell survival. These findings demonstrate the effects of RFTA in triggering apoptosis induced by ROS (\O2(-)) production after visible light irradiation of squamous carcinoma cells.
['Juarez|Andrea V|AV|', 'Sosa|Liliana Del V|Ldel V|', 'De Paul|Ana L|AL|', 'Costa|Ana Paula|AP|', 'Farina|Marcelo|M|', 'Leal|Rodrigo B|RB|', 'Torres|Alicia I|AI|', 'Pons|Patricia|P|']
D017209:Apoptosis D002294:Carcinoma, Squamous Cell D053148:Caspase 3 D002460:Cell Line D049109:Cell Proliferation D053938:DNA Fragmentation D006801:Humans D008027:Light D019950:Mitogen-Activated Protein Kinase 1 D048052:Mitogen-Activated Protein Kinase 3 D010778:Photochemotherapy D017319:Photosensitizing Agents D019253:Proto-Oncogene Proteins c-bcl-2 D017382:Reactive Oxygen Species D012256:Riboflavin D051028:bcl-2-Associated X Protein D048051:p38 Mitogen-Activated Protein Kinases
Apoptosis Photodynamic therapy SCC-13 cells Riboflavin 2′,3′,4′,5′-tetraacetate