HIGHER SENSITIVITY IN LEC RAT-CELLS TO A TOPOISOMERASE-II INHIBITOR, ELLIPTICINE

A concentration of ellipticine, an inhibitor of topoisomerase II, requ ired to reduce cell survival to 37% (D-37) is used as an index to comp are the cellular sensitivity. D-37 values of LEC and WKAH rat cells we re 1.2 and 2.2 mu M, respectively. Thus, LEC rat cells were approximat ely 1.8-fold more sensitive than WKAH mt cells to ellipticine. There w as no significant difference between the topoisomerase II activities i n nuclear extracts of LEC and WKAH rat cells. These results suggested that the high sensitivity of LEC rat cells to ellipticine is not assoc iated with the level of topoisomerase II activity.