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 occupational contaminant trichloroethylene, were studied in primary cultures of human proximal tubular (hPT) cells. Cells from male and female donors were incubated with a range of concentrations of DCVC (10 to 1000 microM) for up to 48 h, and assessments of cellular morphology (phase-contrast microscopy), necrosis (lactate dehydrogenase (LDH) release), apoptosis(cell cycle analysis, annexin V staining, and caspase activation), and proliferation (cell cycle analysis and DNA synthesis) were made. Time- and concentration-dependent changes in cellular morphology, including elongation of cell shape, formation of intracellular vesicles, and formation of apoptotic bodies, were observed. Significant increases in LDH release occurred in hPT cells incubated with < or =100 microM DCVC for at least 24 h. hPT cells from males were modestly more sensitive to DCVC than those from females, with maximal LDH release of 78 and 65% in cells from males and females, respectively. Flow cytometry analysis of propidium iodide-stained and DCVC-treated hPT cells showed that apoptosis occurred at markedly lower concentrations (10 microM) and at much earlier incubation times (2 h) than necrosis. A small increase was also noted in the percentage of cells in S-phase after a 4-h treatment with as little as 10 microM DCVC, suggesting that cell proliferation was stimulated. This was supported further by increased DNA synthesis. These results show that DCVC causes apoptosis and enhances cell proliferation in hPT cells at environmentally relevant doses and at earlier time points and lower concentrations than necrosis.