It has been demonstrated that
cancer cells are under high levels of oxidative stress and express high levels of
Manganese superoxide dismutase (MnSOD) to protect themselves and support the anabolic metabolism needed for growth and cell motility. The aim of this study was to identify
proteins that may have a correlation with invasion and redox regulation by mitochondrial
reactive oxygen species (ROS). MnSOD scavenges
superoxide anions generated from mitochondria and is an important regulator of cellular redox status. Oxidative posttranslational modification of
cysteine residues is a key mechanism that regulates
protein structure and function. We hypothesized that MnSOD regulates intracellular reduced
thiol status and promotes
cancer invasion. A proteomic
thiol-labeling approach with
5-iodoacetamidofluorescein was used to identify changes in intracellular reduced
thiol-containing
proteins. Our results demonstrate that overexpression of MnSOD maintained the major structural
protein, actin, in a reduced state, and enhanced the invasion ability in gastric mucosal
cancer cells, RGK1. We also found that the expression of
Talin and S100A4 were increased in MnSOD-overexpressed RGK1 cells. Moreover,
Talin bound not only with actin but also with S100A4, suggesting that the interaction of these
proteins may, in part, contribute to the invasive ability of rat
gastric cancer.