SELECTIVE INDUCTION OF PROGRAMMED CELL DEATH (APOPTOSIS) IN MALIGNANT CELLS BY THE ALKALOID DERIVATIVE UKRAIN (NSC-613570).

Andrejs Liepins and Jaroslaw W. Nowicky,

Memorial University, Faculty of Medicine, St. John's, NF, Canada A1B 3V6 and
Ukranian Anti-cancer Institute, Matgaretenstrasse 7, A-1040 Vienna, Austria.

The discovery and development of drugs or agents that could induce either lethal damage to malignant cells directly or via the activation of immune effector cells are two of the major strategies in cancer therapy. Programmed cell death (PCD) or apoptosis is an active cell death process characterised by cell surface blebbing, changes in membrane permeability, nuclear DNA condensation and fragmentation. We have investigated whether Ukrain, an alkaloid thiophosphoric semisynthetic compound, would induce PCD selectively in malignant cells. For this purpose we utilized leukemia K562, HL-60 and THΡ-1 cells m our test panel. As controls, we used normal human PBLs, umbilical vein endothelial cells and human fibroblasts. Cells were plated in 24-well plates at 1-2 x 10⁶ cells per well and exposed to serial dilutions of Ukrain, ranging from 2.0 to 64 μΜ and cultured at 37°C + 5.0% CO₂ in RPMI + 10% FBS. The appearance of apoptosis, as manifested by cell surface blebbing, was monitored microscopically a various time intervals after the addition of drug. Results showed that Ukrain at 8.0 and 16.0 μΜ induced apoptosis in K562, HL-60 and THP-1 within 2-3 hrs in ≥ 80% of the cells. Lower concentrations of Ukrain required longer time periods to induce apoptosis. Shifts in DNA conten were analyzed by flow cytometry. Thus, the alkaloid derivate ukrain induces selective cytotoxicity on malignant cells via PCD or apoptosis. Significantly, normal cells were not sensitive to Ukrain even at the highest drug concentration tested (64.0 μΜ).