Apoptosis, necrosis, and cell proliferation induced by S-(1,2-dichlorovinyl)-L-cysteine in primary cultures of human proximal tubular cells

Apoptosis, necrosis, and cell proliferation induced by S-(1,2-dichlorovinyl )-L-cysteine (DCVC), the cysteine conjugate of the environmental and occupa tional contaminant trichloroethylene, were studied in primary cultures of h uman proximal tubular (hPT) cells. Cells from male and female donors were i ncubated with a range of concentrations of DCVC (10 to 1000 muM) for up to 48 h, and assessments of cellular morphology (phase-contrast microscopy), n ecrosis (lactate dehydrogenase (LDH) release), apoptosis (cell cycle analys is, annexin V staining, and caspase activation), and proliferation (cell cy cle analysis and DNA synthesis) were made. Time- and concentration-dependen t changes in cellular morphology, including elongation of cell shape, forma tion of intracellular vesicles, and formation of apoptotic bodies, were obs erved. Significant increases in LDH release occurred in hPT cells incubated with less than or equal to 100 muM DCVC for at least 24 h. hPT cells from males were modestly more sensitive to DCVC than those from females, with ma ximal LDH release of 78 and 65% in cells from males and females, respective ly. Flow cytometry analysis of propidium iodide-stained and DCVC-treated hP T cells showed that apoptosis occurred at markedly lower concentrations (10 muM) and at much earlier incubation times (2 h) than necrosis. A small inc rease was also noted in the percentage of cells in S-phase after a 4-h trea tment with as little as 10 muM DCVC, suggesting that cell proliferation was stimulated. This was supported further by increased DNA synthesis. These r esults show that DCVC causes apoptosis and enhances cell proliferation in h PT cells at environmentally relevant doses and at earlier time points and l ower concentrations than necrosis. (C) 2001 Academic Press.