ABSTRACT
<p><b>OBJECTIVE</b>To investigate the association of advanced oxidation protein products (AOPP) with oxidative stress in colon cancer cells exposed to intermittent hypoxia (IH).</p><p><b>METHODS</b>Colon cancer SW480 cells were exposed to IH, continuous hypoxia, or normoxia. Enzyme-linked immunosorbent assay (ELISA) was employed to examine the levels of AOPP and vascular endothelial growth factor (VEGF), xanthine oxidase assay was used to determine malonaldehyde (MDA) and glutathione peroxidase (GSH-PX), and Western blotting and immunofluorescence assay were performed for detection of transforming growth factor-β(1) (TGF-β(1)) expression.</p><p><b>RESULTS</b>Compared with the normoxia group, the two hypoxia groups showed significantly increased AOPP and MDA levels (P<0.05) and lowered SOD and GSH-PX levels (P<0.05). The concentration of AOPP was positively correlated to MDA, VEGF, and TGF-β(1) levels (P<0.05), but inversely to SOD. No significant correlation was found between AOPP and GSH-PX levels.</p><p><b>CONCLUSION</b>Compared with continuous hypoxia, IH results in more obvious protein oxidation in relation to oxidative stress. The increased expression of VEGF and TGF-β(1) in the context of hypoxia is closely related to AOPP level.</p>