In vitro Anticancer Effect of Gracilaria Foliifera on Human Oral Squamous Cell Carcinoma

Objectives: To evaluate the anticancer efficacy of Gracilaria foliifera (GF), a marine algae on human oral squamous cell carcinoma (SCC-25) cells.
Methods: Cytotoxic effect of GF was determined by MTT assay, using different concentrations for twenty four hours. Gracilaria foliifera was treated SCC-25 cells with 20, 40 and 80 µg/L. Reactive oxygen species (ROS) generation was investigated by the dichlorofluorescein fluorescent staining assay. Dual acridine orange/ethidium bromide (AO/EB) fluorescent stained SCC-25 cells were visualized under a fluorescent microscope for apoptosis related membrane damage. Mitochondrial membrane potential has been investigated by rhodamine staining assay. p53 gene and protein expression was evaluated respectively by PCR and western blotting analysis.
Results: Gracilaria treatment caused significant (P<0.001) cytotoxicity and increased in SCC- 25 cells volume and showed uneven orange-red fluorescence at their periphery further confirms the apoptosis. Gracilaria treatment also induced significant (P<0.001) ROS generation with concomitant decrease in the mitochondrial membrane potential. There was a significant increase in the tumor suppressor p53 expression at protein and gene level.
Conclusions: Gracilaria treatment caused dose-dependent cytotoxicity in SCC-25 cells by virtue of ROS generation this could have subsequently caused decrease in mitochondrialmembrane potential and membrane damage. Increase in p53 expressions further confirms the anticancer and proapoptotic potentials of Gracilaria. These results suggest that Gracilaria can be used as a modulating agent in oral squamous cell carcinoma.