Quercetin inhibits invasion and angiogenesis of esophageal cancer cells.

Background: Esophageal carcinoma has poor prognosis and novel therapies for esophageal carcinoma are urgently needed. Quercetin is a natural flavonoid compound that can be found in many foods. In this study, we investigated the effects of quercetin on invasion and angiogenesis of esophageal cancer cells.

Methods: Human esophageal cancer cell line Eca109 was treated with 5 μg/mL or 10 μg/mL of quercetin. Colony formation assay was performed. Cell migration and invasion were evaluated by wound healing and transwell assays, respectively. Human umbilical vein/vascular endothelium cells (CLR-1730) were treated with Eca109 conditioned medium, and the effects of quercetin on CLR-1730 were evaluated by wound healing and tube formation assays. Protein levels of VEGF-A, MMP9, and MMP2 were determined by Western blotting.

Results: The ability of colony forming in Eca109 was reduced with the administration of 10 μg/mL quercetin, but there was no difference between the 5 μg/mL quercetin group and control. The migration distance and the number of invasive cells were significantly reduced in the 10 μg/mL quercetin group. At the lower level of quercetin at 5 μg/mL, only the invasion of cells was significantly inhibited. In endothelial cells treated with Eca109 conditioned medium, cell migration and tube forming ability were suppressed. The decreased protein levels of VEGF-A, MMP9, and MMP2 were observed at the 10 μg/mL quercetin group.

Conclusion: Quercetin suppressed the invasion and angiogenesis of esophageal cancer cells, and the effects were associated with the decreased expression of VEGF-A, MMP2, and MMP9.