科研之友
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Purpose. The purpose of this study was to characterize the concentration-dependent induction of apoptosis by anticancer drugs in vitro. Methods: The apoptosis-and necrosis-inducing potential of the anticancer drugs cladribine (CDA), cytarabine (ARA-C), cisplatin (CDDP), and 5-fluorouracil (5FU) were studied in vitro in the human leukemia cell lines HSB2 and Jurkat using a flow-cytometry assay that permits the simultaneous quantification of vital, apoptotic, and necrotic cells by double-staining with fluorescein isothiocyanate (FITC)-labeled Annexin-V and propidium iodide. The results were fit to different multicompartmental models and the sensitivity of the cell lines to apoptosis and necrosis was estimated. Results: A time- and dose-dependent decrease in vital cells as cell as an increase in apoptotic and necrotic cells was observed in HSB2 cells upon continuous incubation with 10(-5)-10(-7) M CDA, 10(-5)-10(-8) MARA-C, 5 x 10(-5) x 10(-6) M CDDP, and 10(-4)-10(-5) M 5FU, whereas no effect was observed relative to controls upon incubation with 10(-8)-10(-9) M CDA, 10(-9) M ARA-C, 10(-7)-10(-8) M CDDP, or 10(-6)-10(-9) M 5FU. In Jurkat cells, apoptosis- and necrosis-inducing effects were observed at 10(-4) 5 x 10(-6) M CDA, 10(-5)-10(-7) M ARA-C, 5 x 10(-5)-5 x 10(-6) M CDDP, and 10(-4)-10(-5) M 5FU. In all experiments, apoptotic cells reached a peak after 6-48 h of drug exposure. These data were best fit by a model in which vital cells became irreversibly apoptotic by a direct pathway and necrotic by an irreversible indirect pathway following the apoptotic state (mean R = 0.9876; range 0.9510-0.9993; mean modified Akaike's information criterion 3.88; range 1.86-5.82) and the rate constants of either pathway (Kva and Kan, respectively) were assessed. The sensitivity of both cell lines to apoptosis and necrosis (expressed as EC50 and E-max values) induced by the anticancer drugs could be calculated from the sigmoidal concentration-effect curves. Furthermore, it was shown that drug treatment (10(-6) M CDA or 10(-6) M ARA-C) potentiated the apoptosis-inducing effects of irradiation (6 Gy) but not its necrosis-inducing potential. Conclusion: This study demonstrates that CDA, ARA-C,CDDP, and 5FU possess concentration-dependent apoptosis-inducing potential in the cell lines studied. The cytotoxic mechanism and cell-killing potential of these drugs is different, which is reflected by different EC50 and E-max values. Furthermore, a method for pharmacodynamic modeling is introduced that permits a quantitative approach for the assessment of the sensitivity of tumor cells to anticancer drugs and combined treatments.
- 出版日期1998-6
