The Effect of Topotecan on Human SPC-A-1 Lung Cancer Cells

Objective To study the Topotecan(TPT) induced apoptosis of human SPC A 1 lung cancer cells and its possible mechanism.Methods Cells were incubated with TPT(20 mg/L) for 12,24 and 48 h.Cell viability was measured by MTT assay. Morphological changes of apoptotic cells was studied by TUNEL staining. Apoptotic rates of cells incubated with TPT or TPT and 50 μmol/L Ac DEVD CHO(specific Caspase 3 inhibitor)were detected by flow cytometer.Results Cell viability with 20 mg/L TPT for 12,24 and 48 h were (85.8±9.7)%, (76.5±6.5)% and (64.6±10.4)% respectively.Cell viability without TPT was (97.1±6.9)%.There was a significant reduction of cell viability with time duration of TPT( P 0 05).Typical morphological features of apoptotic cells were detected by TUNEL staining.Apoptotic rates of cells with TPT for 12,24 and 48 h studied by flow cytometer were (3.4±1.5)%,(11.5±2.8)% and (31.2±4.1)% respectively. There was a significant rising apoptotic rates with time duration( P 0 01). Apoptotic rates of cells with TPT and Ac DEVD CHO for 12,24 and 48 h were 0,( 5.5±1.6)% and (18.6±3.7)% respectively,lower than cells without Ac DEVD CHO( P 0 01).Conclusions TPT can act effectively as chemotherapeutic drugs for lung cancer by leading cancer cells to apoptosis through Caspase 3 activation and the function is time dependent.