CELL KILL AND CYTOSTASIS BY ET-18-OCH3 AND HEAT

Background: The ether lipid analogue 1-octadecy-2-methyl-rac-glycero-3 -phosphocholine (ET-18-OCH3) is known to have plasma membrane interact ing antitumor activity. However, the mechanism and the mode of action of its activity remain to be elucidated fully. Materials and Methods: In this study, the proportion of the inhibitory effects resulting eith er fiom direct cell kill or from cytostasis induced by (ET-18-OCH3) al one or in combination with heat in BG-I human ovarian carcinoma cells was quantitated. Results: The magnitude of both cell kill and cytostas is in BG-I cells was dependent on the concentration of ET-18-OCH3 and the duration of exposure. Cell kill, induced by exposure to 2 or. 8 mu M ET-18-OCH3 for 1-14 days could be expressed as a simple exponential function of exposure dose (concentration x time). As assayed by colon y formation, cell survival after continuous exposure to the drug was s ignificantly reduced from that measured when the drug was removed and the cells were incubated for 14 days in drug-free medium: Conclusions: We conclude that ET-18-OCH3 induces substantial cytostasis as well as cell kill in BG-I cells and that this cytostasis is directly proporti onal to the amount of cell kill induced These data are important in de termining appropriate treatment regimens using ET-18-OCH3 either alone or in combination with other anticancer agents.