Abstract
Toxicity associated with plasmid/liposome transfection of eucaryote cells has been attributed to the inherent toxicity of cationic lipid formulations and also to bacterial contaminants of plasmid DNA preparations, such as lipopolysaccharides (LPS). Certain plasmid preparations were observed to trigger apoptosis in DNA/liposome transfected OVCAR3 human epithelial ovarian cancer cells. In contrast, AZ224 and SKOV3 cells were unaffected under the same conditions. Agarose gel electrophoresis with recovery of the plasmid DNA removed the toxic component, but not purification by phenol/chloroform extraction or isopicnic CsCl ultracentrifugation. The toxicity of individual preparations correlated with the concentration of bacterial LPS. However, polymixin B could not neutralise the toxicity and neither could the effect be reproduced by the addition of bacterial LPS to non-toxic plasmid preparations. Surprisingly, the conditioned medium of OVCAR3 cells undergoing apoptosis was found to kill non-transfected OVCAR3 cells but not AZ224 or SKOV3 cells. This observation illustrates the possibility that unpredictable contaminants of bacterial plasmid preparations are able to cause cell death in the context of plasmid/liposome transfection in a cell-type specific way. It emphasizes the importance of achieving maximal plasmid DNA purity when performing DNA transfection experiments that focus on cell survival.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
