Curcumin inhibits the lymphangiogenesis of gastric cancer cells by inhibiton of HMGB1/VEGF-D signaling

Accumulating evidence shows that curcumin exerts antitumor activities in a variety of malignancies. High mobility group box 1 (HMGB1) is associated with vascular endothelial growth factor D (VEGF-D)-induced lymphangiogenesis and tumor metastasis in gastric cancer. However, the molecular mechanisms by which curcumin regulates HMGB1-mediated lymphangiogenesis in gastric cancer remain unclear. In this study, the cytotoxic effects of curcumin were investigated in gastric cancer AGS and SGC-7901 cell lines by MTT assay, and curcumin-induced morphological changes and cell apoptosis were assessed by using flow cytometry analysis and caspase-3 activity. The effects of curcumin on HMGB1 and VEGF-D expression were examined by reverse transcription polymerase chain reaction (RT-PCR) and western blot analysis. As a result, we found that curcumin decreased cell viability and caused a dose-dependent cell apoptosis through the activation of caspase-3. The mRNA and protein expression levels of HMGB1 and VEGF-D were significantly eliminated by curcumin administration. Pre-treatment with the recombinant HMGB1 (rHMGB1) markedly abolished curcumin-reduced VEGF-D expression. Our findings suggested that curcumin might exert anti-lymphangiogenesis in gastric cancer by inhibition of HMGB1/VEGF-D signaling.