RESUMEN
<p><b>OBJECTIVE</b>To investigate the toxicity of cationic liposome Lipofectamine 2000 (Lipo) in human pancreatic cancer Capan-2 cells.</p><p><b>METHODS</b>Capan-2 cells were cultured in the presence of Lipo at toxic concentrations, and the cell growth, apoptosis and cell cycle changes were evaluated by cell counting and flow cytometry.</p><p><b>RESULTS</b>The concentrations of both Lipo and siRNA affected the transfection efficiency. In a transfection volume of 2 ml, the presence of 5 microl Lipo resulted in slowed growth of Capan-2 cells, which was especially obvious after 3 days (P<0.001). Prolonged culture of the transfected cells caused significant increases in early apoptotic cells (P<0.05) and in the damaged or necrotic cells (P<0.001), and resulted in reduced viable cells (P<0.01); these changes became obvious after a 48-hour culture, which also increased the ratio of G(0)/G(1) phase cells (P<0.05) and decreased those of G(2)/M phase cells (P<0.01), S phase cells (P<0.01), and the late apoptotic cells (P<0.05).</p><p><b>CONCLUSION</b>Toxic concentrations of Lipo can affect the growth, apoptosis and cell cycles of Capan-2 cells in vitro, and this urges careful concentration selection when using Lipo for gene transfer into different cells.</p>