Glycer-AGEs-RAGE signaling enhances the angiogenic potential of hepatocellular carcinoma by upregulating VEGF expression

AIM: To investigate the effect of glyceraldehyde-derived advanced glycation end-products (Glycer-AGEs) on hepatocellular carcinoma (HCC) cells. METHODS: Two HCC cell lines (Hep3B and HepG2 cells) and human umbilical vein endothelial cells (HUVEC) were used. Cell viability was determined using the WST-8 assay. Western blotting, enzyme linked immunosorbent assay, and real-time reverse transcription-polymerase chain reactions were used to detect protein and mRNA. Angiogenesis was evaluated by assessing the proliferation, migration, and tube formation of HUVEC. RESULTS: The receptor for AGEs (RAGE) protein was detected in Hep3B and HepG2 cells. HepG2 cells were not affected by the addition of Glycer-AGEs. Glycer-AGEs markedly increased vascular endothelial growth factor (VEGF) mRNA and protein expression, which is one of the most potent angiogenic factors. Compared with the control unglycated bovine serum albumin (BSA) treatment, VEGF mRNA expression levels induced by the Glycer-AGEs treatment were 1.00 +/- 0.10 vs 1.92 +/- 0.09 (P < 0.01). Similarly, protein expression levels induced by the Glycer-AGEs treatment were 1.63 +/- 0.04 ng/mL vs 2.28 +/- 0.17 ng/mL for the 24 h treatment and 3.36 +/- 0.10 ng/mL vs 4.79 +/- 0.31 ng/mL for the 48 h treatment, respectively (P < 0.01). Furthermore, compared with the effect of the control unglycated BSA-treated conditioned medium, the Glycer-AGEs-treated conditioned medium significantly increased the proliferation, migration, and tube formation of HUVEC, with values of 122.4% +/- 9.0% vs 144.5% +/- 11.3% for cell viability, 4.29 +/- 1.53 vs 6.78 +/- 1.84 for migration indices, and 71.0 +/- 7.5 vs 112.4 +/- 8.0 for the number of branching points, respectively (P < 0.01). CONCLUSION: These results suggest that Glycer-AGEs-RAGE signaling enhances the angiogenic potential of HCC cells by upregulating VEGF expression. (C) 2012 Baishideng. All rights reserved.