EXPERIMENTAL AND CLINICAL-EVALUATION BY FLOW-CYTOMETRY FOR THE MECHANISM OF COMBINATION THERAPY (CISPLATIN AND PEPLOMYCIN)

Pharmacologic effects of cisplatin (CDDP) and peplomycin (PEP) on tumo r cell kinetics were studied both in vitro and in vivo with the aid of flow cytometry (FCM). Double staining with propidium iodide (PI) and fluorescein isothiocyanate (FITC)-labeled bromodeoxyuridine (BrdU) was used to analyze the cell cycle, and the number of viable cells was de termined with fluorescein diacetate (FDA). Effects of combining the 2 agents were also studied to establish the most effective method of com bination therapy. Furthermore, these agents were tried clinically on t he basis of experimental results. Results showed that CDDP exerted its action at the S and G2M phases in the cell cycle and PEP at the G2M p hase. Among the combination regimens in the experiments with CDDP, PEP , and CDDP + PEP as analyzed by FCM, the strongest block on the G2M ph ase was shown in the one at a 2-day interval, resulting in the most ef fective killing of the tumor cells. Clinical trial of the combination therapy showed the same results as the in vitro experiment; the therap y proved useful for improving the patient's clinical condition and the results obtained with CT imaging and pathology.