Phenethyl isothiocyanate Induces ROS Production to Cause DNA Damage and Subsequent Apoptosis in Oral Cancer Cells.
| Autor: | Hua Yeh, 葉樺 |
|---|---|
| Rok vydání: | 2013 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 101 Phenethyl isothiocyanate ( PEITC ) is a kind of major components found in cruciferous vegetables and has been proven to be the anti-carcinogenic and have the potential for chemoprevention. This study aimed to investigate the possible application and underlying mechanisms of PEITC in treating oral cancer. In the present study, we examined the effects of PEITC on the cell growth, O2-, H2O2 and NO production, DNA damage response, cell cycle progression and apoptosis induction in the oral cancer cell line, OC2. The results showed that PEITC exposure induced apoptosis in a dose an time-dependent manner through promoting the production of O2-, H2O2 and NO, reduction of cellular GSH content, incorporation of 8-OHdG, formation of nuclear DNA tailing, arrest of cell cycle at the G2/M phase and enrichment of the Sub-G1 phase cell population through triggering the release of Cytochrome C from the mitochondria and reducing the transmembrane potential of the mitochondria. Interestingly, treatment of PEITC did not affect the cell survival of the PBMC and CCD-966SK cells, suggesting PEITC might not hurt normal cells. Further examination of the underlying mechanism for the cytotoxicity of PEITC revealed that PEITC increased activation of ATM, Chk2 and p53 and reduced the expression of Cdc25C, Cdc2, and Cyclin B1. In addition, PEITC decreased the expressions of Bcl-2 and Mcl-1, and increased those of Bax, cleaved Caspase 3 and cleaved PARP. Pre-treatment with the antioxidant, NAC or GSH, Cell survival can be raised to 90% or more, and the apoptosis reduced to 10%. The pretreatments reversed PEITC-mediated ROS production, DNA damage production, cell cycle arrest, mitochondrial transmembrane potential reduction, cellular GSH content loss, p-Chk2 downregulation, and Bcl-2, Mcl-1 up-regulation. We noticed that the p53 might provide the link among ROS-mediated DNA damage response, cell cycle arrest, and apoptosis. Indeed, pre-treatment with the p53 inhibitor, Pifithrin-α, raised the cell survival rate about 92% or more in oral cancer OC2, SCC25 and SCC4 cells; the data showed that PEITC-mediated inhibition of oral cancer cells might function through a p53-dependent pathway regardless of the mutant p53. Taken together, these results suggested that the exposure of OC2 cells to PEITC might induce apoptosis through promoting a rapid production of ROS to damage DNA and inducing a p53-dependent induction of cell cycle arrest and apoptosis. Further investigations are required. Hopefully, PEITC will become an effective adjuvant treatment for oral cancer. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|