PURPOSE: This study was conducted to determine the in vitro optimal combination of selected anticancer agents with gefitinib and evaluate its effect on the expression of correlative biological targets in the cell-signaling pathway. In addition, the effect of gefitinib on the expression of ATP-binding cassette (ABC) transport proteins was evaluated. METHODS: Growth inhibition assays were conducted in five human ovarian cancer cell lines to evaluate the activity of selected anticancer agents in combination with gefitinib compared to each alone. Enzyme linked immunosorbant assay (ELISA) assessed the presence of pEGFR in treated and untreated cells. Expression of correlative biological targets in the cell-signaling pathway was completed by immunoblotting. RT-PCR was used to characterize the expression ABC transport proteins. RESULTS: This in vitro study confirmed gefitinib did not have significant cytotoxic activity, the combination of gefitinib with other chemotherapy drugs demonstrated improved in vitro cytotoxic activity in platinum sensitive ovarian cancer cell lines. Suppression of pAKT and p-erk activation in cells treated with combination of cisplatin and gefitinib was observed and suggests the role of gefitinib inhibition of proliferative cell signaling pathway. CONCLUSION: This data suggests that EGFR-inhibitors, such as gefitinib, have the potential to modulate common mechanisms of drug resistance and may have a role in optimizing chemotherapy regimens for the treatment of ovarian cancer.
PURPOSE: This study was conducted to determine the in vitro optimal combination of selected anticancer agents with gefitinib and evaluate its effect on the expression of correlative biological targets in the cell-signaling pathway. In addition, the effect of gefitinib on the expression of ATP-binding cassette (ABC) transport proteins was evaluated. METHODS: Growth inhibition assays were conducted in five humanovarian cancer cell lines to evaluate the activity of selected anticancer agents in combination with gefitinib compared to each alone. Enzyme linked immunosorbant assay (ELISA) assessed the presence of pEGFR in treated and untreated cells. Expression of correlative biological targets in the cell-signaling pathway was completed by immunoblotting. RT-PCR was used to characterize the expression ABC transport proteins. RESULTS: This in vitro study confirmed gefitinib did not have significant cytotoxic activity, the combination of gefitinib with other chemotherapy drugs demonstrated improved in vitro cytotoxic activity in platinum sensitive ovarian cancer cell lines. Suppression of pAKT and p-erk activation in cells treated with combination of cisplatin and gefitinib was observed and suggests the role of gefitinib inhibition of proliferative cell signaling pathway. CONCLUSION: This data suggests that EGFR-inhibitors, such as gefitinib, have the potential to modulate common mechanisms of drug resistance and may have a role in optimizing chemotherapy regimens for the treatment of ovarian cancer.