Acta Morphologica Academiae Scientiarum Hungaricae [antikvár]

Acta Morphologica Acad. Sci. Hung. 24 (4), pp. 297 — 305, 1976 Research Institute of Oncopathology, Budapest CELL SURFACE PROPERTIES OF L1210 LEUKAEMIA CELLS Orsolya CsUKA and J. SuGAR (Received June 25, 1976) The surface properties of vincristine-colchicine sensitive and resistant L1210 leukaemic cells have been studied using concanavalin A mediated agglutination assay as well as electron microscopic visualization of concanavalin A receptors. ^H-colchicine uptake by the sensitive and resistant lines has also been compared. The resistant L1210 leukaemic cells proved less agglutinable than the sensitive ones at the same concanavalin A concentration. Previous treatments with either colchicine, vincristine or chlor-promazine caused a marked decrease in the agglutinability of the sensitive L1210 leukaemic cells, while agglutination of the resistant ones was lowered slightly by the same treatments. The ^H-colchicine uptake of the sensitive cells was three times higher than that of the resistant ones. Introduction Vinca alkaloids are widely used in the treatment of leukaemias. It is well established that these drugs arrest cells in metaphase by dissolution of the mitotic spindle. It has therefore been supposed that the antitumour effect of vinca alkaloids is due to their antimitotic action [1, 4, 8, 10]. An immediate cytolytic effect of vincristine on the interphase lymphoblast and non-dividing lymphocytes derived from chronic lymphocytic leukaemias has, however, also been demonstrated [11, 12]. It has been shown in addition that exponentially growing human lymphoid cell cultures are comparatively resistant, while their cells in Gj phase increasingly sensitive, to vincristine [9]. Therefore, it is not clear whether the antimitotic effect or the cytolysis of the non-dividing cells (by disruption of the cell membrane) was responsible for the antitumour activity of these drugs. Assuming that the cell membrane is the primary target for the action of vinca alkaloids, changes in the surface properties of the cells should affect their sensitivity to these drugs. Thus, a comparison of the surface properties of vincristine-colchicine sensitive and resistant L1210 leukaemias seemed to be a useful tool for detecting the therapeutic mechanism of vinca alkaloids. Ada Morphologica Academiae Scientiarum Hungaricae 24,1976