Anionicpolymers. IV. Microelectrophoresis of ascites tumor cells and the effect of polyxenylphosphate.

The d is t r ibut ion of rad ioac t iv i ty in tissues, par t icu lar ly in tumors, of mice given inject ions of cer ta in prepara t ions of the anionic polymer , polyxenyl phospha te (PXP) ~ labeled with ps2, are explained nei ther on the basis of ret iculoendothel ial ac t iv i ty nor solely by hydrolysis and subsequen t up take of p32-orthophosphate (1~). One of several explanat ions migh t be t h a t P X P is bound to cell surfaces. To explore this possibili ty, Ehr l ich and Sarcoma 180 ascites tumors were selected so t h a t independen t neoplast ic cells could be used to de termine the extent of surface binding by means of microelectrophoresis. Microelectrophoresis has been extensively used to s tudy the surface characteristics of cell s t ructures (s 7, 11, 13-15). The net charge of the surface of a microscopically visible cell m a y be calculated from its rate of migra t ion in an electric field (1), provided the ionic s t rength , viscosity, and the field s t rength are known. If P X P is bound to the cell surfaces, the mobi l i ty of the ascites cells toward the anode would be increased. Thus , the q u a n t i t y of po lymer bound to the cell surfaces m a y be es t imated from the dimensions of the t umor cells and the charge dens i ty of the polymer.