Fate of Transgenic 5-Enolpyruvyl-Shikimate-3-Phosphate Synthase (Cp4 Epsps) Dna from Roundup Ready Canola in Intestinal Epithelial Caco-2 Cells

We investigated the stability and fate of 5-enolpyruvyl-shikimate-3-phosphate synthase (cp4 epsps) DNA from Roundup Ready canola, in human intestinal Caco-2 cells in vitro and monitored the process at 0.5, 1, 2, 4 and 24 h. We found that 1.3 kb cp4 epsps transgenic DNA degraded rapidly and could not be detected by PCR in the culture media, cell washes or in DNA extracted from cells as early as 0.5 h of culture. However, transgenic fragments (278- and 270- bp) could be detected from culture media at all time points especially at higher concentrations (100 ng mL 1). These fragments were detected from Caco-2 cell as early as 0.5 h and were consistently found at 1, 2, 4 and even at 24 h. The detection of transgene fragments from DNA extracted from cells was also observed at 4 C. Our results suggest that transgenic DNA fragments are associated with and possibly internalized by Caco-2 cells. To further support this observation, experiments were modified to include DNase I treatment and high salt washes. DNase I treatment removed all extracellular DNA; however DNA fragments were still detected in DNA extracted from cells. Thus 1.3 kb cp4 epsps is prone to rapid degradation but transgene fragments are cell-associated in human intestinal cells in vitro.