Effect of Cisplatin on Transepithelial Resistance and Ion Transport in the A6 Renal Epithelial Cell Line

Abstract

Cisplatin is a platinum-containing antitumour agent, the usefulness of which is limited by nephrotoxicity. In the present study, we examined the effects of cisplatin on the established renal epithelial A6 cell line, which forms a polarized monolayer in vitro with active transmembrane ion transport. The effect of cisplatin (0–800 μ m) on transepithelial ion transport and transepithelial resistance (TER) was monitored by the short-circuit current (SSC) technique. Cell integrity was determined by monitoring TER at increasing concentration of cisplatin during 24 hours. The half-maximal inhibition concentration was 49 and 540 μ m when applied to either the basolateral or apical surface, respectively. This suggests that cisplatin-mediated deterioration of cell integrity is far more pronounced when cisplatin is applied basolaterally than apically. Continuous measurements of TER demonstrated a dose- and time-dependent decline in TER/TER 0 (TER at time zero). In addition, cisplatin from the basolateral side had no prompt effect on transepithelial ion transport. Instead a slow, but dose-dependent decline which at the highest concentration resembled the decline observed when ouabain was added. Inhibition of Na-K-ATPase by cisplatin was examined by the use of nystatin, a membrane permeabilizer, and data suggest that cisplatin at 800 μ m inhibits Na-K-ATPase by about 50% after 60 minutes of exposure. Morphological examinations of subcultured cisplatin treated cells indicate that cell death is probably due to apoptosis rather than necrosis.