Enhancement of Cytotoxicity of Chemotherapeutic Agents by Buthionine sulfoximine in Retinoblastoma Cell Line

ABSTRACT

This study was performed to evaluate in vitro cytotoxicity of chemotherapeutic agents in established human retinoblastoma cell line, Y79 and to study the possibility of enhancing the cytotoxicity of chemotherapeutic agents by administration of buthionine sulfoximine(BSO) which lowers the intracellular glutathione(GSH) level. IC50 defined as the concentration which inhibits the cell survival rates to 50% compared with control group was used to evaluate cytotoxicity. Intracellular level after 13.50 adminstration were measured and compared with the level prior to administration of BSO. Doxorubicin, cisplatin, and melphalan showed significant decrease of IC50 by administration of BSO(p0.05). Intracellular GSH level prior to the administration of BSO was 0.931nM/mg protein. After the administration of BSO, they were lowered to 0.095nM/mg protein in both BSO concentrations. Results listed above suggest that cytotoxicity of doxorubicin, cisplatin, and melphalan can be enhanced by ESO. This effect may be mediated by decreased intracellualr level of GSH by BSO.