Microfluorometric investigations on the cell cycle progression of experimental ascites tumors treated with alkaloidic drugs.

The effects of the antitumor agents vincristine (VCR) and vincaleucoblastine (VLB) on the cell cycle progression of three different ascites tumor cell lines in vivo (Ehrlich, Crocker S 180, and leukemia L 1210) were studied in detail by flow microfluorometric techniques over a 5-day period of drug treatment and during the post-treatment course. These investigations give evidence that the tumor lines employed show completely different sensitivity against VCR and VLB. During the treatment massive polyploidization was demonstrated to be, in general, the second response of treated cells overcoming an initial proliferative block in the G 2 phase of their life cycle.