Thesis (Ph.D.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Oral and Maxillofacial Pathology

Head and neck cancers were ranked as the sixth most common cancer worldwide and still a major cause for death. Objectives: the aim of the study was to examine the antioxidant and apoptotic effect of pomegranate extract (PE), reactive oxygen species (ROS), and their combination on oral squamous cell carcinoma (OSCC) cell line. Methods and results: Two cell lines were used, namely, SCC15 derived from tongue squamous cell carcinoma and normal gingival keratinocytes, which was used as normal control. They were divided into eight groups, four for each cell line, three of which were subjected to PE, H2O2 and a combination of both with the fourth being used as control. Doses were determined using the MTT viability assay. Cell cycle and apoptosis analysis were assessed using flow cytometry. Early and late apoptosis indicators, namely cytochrome c (CYT-C) and caspase3, respectively were measured by Elisa and the antioxidant capacity was detected by Nrf2 at both RNA and transcribed protein levels using RT-PCR and Elisa, respectively. Results revealed that PE, H2O2 and their combination have promising effects. A selective cytotoxic and apoptotic inducing effect were seen towards cancer cells rather than normal cells. The percentage of viable cells were decreased in the treated SCC groups compared to normal groups and untreated control groups in G0/G1 and S cell cycle phases. On the contrary, increase in mean percentage of cells in G2/M and apoptosis phases in all SCC treated groups was observed. The levels of CYT-C and caspase3, were elevated in the treated SCC groups compared to normal cell groups and untreated control groups. Moreover, upregulation of the Nrf2 at both gene and protein levels was also detected, which reflected the antioxidant effect of pomegranate and the defense-inducing mechanism of H2O2

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