Cisplatin-induced apoptosis in human proximal tubular epithelial cells is associated with the activation of the Fas Fas ligand system

The role of Fas and Fas ligand (Fas-L) in the apoptotic cell death process in cisplatin (CP)-treated human proximal tubular epithelial cells (PTECs) w as examined. The human PTECs were treated with various concentrations (20-8 0 mu M) of CP for 24 h, and the incidence of apoptosis in CP-treated cells was assessed by trypan blue staining, propidium iodide staining, in situ en d labeling, and electron microscopy. The expression of Fas and Fas-L was de tected by immunofluorescence microscopy. The results showed that: (1) CP-tr eatment resulted in a decreased number of Live human PTECs and an increased number of dead cells, (2) CP-treated human PTECs showed an increased rate of apoptosis with its typical morphological features, and (3) expression of both Fas and Fas-L was upregulated in CP-treated human PTECs. These result s indicate that CP treatment induces apoptosis in human PTECs and the activ ation of the Fas/Fas-L system may play an active role in the induction of t he apoptotic cell death process.