Higher sensitivity in LEC rat cells to a topoisomerase II inhibitor, ellipticine

A concentration of ellipticine, an inhibitor of topoisomerase II, required to reduce cell survival to 37% (D37) is used as an index to compare the cellular sensitivity. D37 values of LEC and WKAH rat cells were 1.2 and 2.2 microM, respectively. Thus, LEC rat cells were approximately 1.8-fold more sensitive than WKAH rat cells to ellipticine. There was no significant difference between the topoisomerase II activities in nuclear extracts of LEC and WKAH rat cells. These results suggested that the high sensitivity of LEC rat cells to ellipticine is not associated with the level of topoisomerase II activity.