Reporter: Sui Peng
Mentor: Rhonda F. Souza
Stuart J. Spechler
Progress:
In earlier studies, we have studied effects of UDCA treatment on DCA-induced DNA
damage and NF-kB activation in one benign Barrett’s cell line (BAR-T), which was
exposed to DCA (250 uM) for 5 minutes with or without pretreatment by UDCA
(300uM) for 24 hours. In the last 3 months, we repeated these experiments in another
benign Barrett’s epithelial cell line (BAR-T10).
Results: we got the same results as in the BAR-T cells (please refer to figure in last
progress report). In both cell lines, DCA markedly increased the expression levels of
p-H2AX and p-p65 by Western blot. Following pretreatment with UDCA, in contrast,
DCA caused no increase in those same levels. This increase in DNA damage was
confirmed by p-H2AX foci using immunofluorence and Comet assay.
We then determined: 1) reactive oxygen species (ROS) generation by the ROS
Detection Kit and 2) protein expression levels of glutathione peroxidase 1 (GPX1, an
anti-oxidant), catalase (CAT), SOD1 and SOD2 by Western blotting.
Results: DCA caused a significant increase in ROS generation that was inhibited by
UDCA pretreatment, and UDCA pretreatment caused a marked increase in
expression levels of GPX1 and CAT, but not in SOD1 or SOD2.
Conclusion: UDCA protects against DCA-induced DNA damage and activation of the
NF-kB pathway. In Barrett’s cells, UDCA blocks DCA-induced ROS generation and
increases expression of the anti-oxidant GPX1. These data have been submitted to
as an abstract to the international meeting of the American Gastroenterological
Association.