Polysaccharides isolated from Hedyotis diffusa inhibits the aggressive phenotypes of laryngeal squamous carcinoma cells via inhibition of Bcl-2, MMP-2, and μPA

Hedyotis diffusa, a traditional Chinese herbal medicine, possesses anti-cancer, anti-oxidative, and anti-inflammatory effects. The aim of this study is to explore the anti-tumor potential of Hedyotis diffusa polysaccharides (HDP) in human larynx squamous carcinoma. High performance size-exclusion chromatography analysis indicated the homogeneous nature of HDP. Total carbohydrate content in HDP was 97.3%, without contamination of protein and nucleic acid. HDP suppressed the proliferation of Hep2 human larynx squamous carcinoma cells in a time- and dose-dependent manner. Cell cycle analysis revealed that exposure to HDP (400μg/ml) caused a G0/G1 cell cycle arrest. Moreover, treatment with HDP for 24h induced a significant apoptosis of Hep2 cells, which was accompanied by increased cleavage of caspase-3, caspase-8, and caspase-9 and reduced expression of Bcl-2 protein. Additionally, HDP inhibited cell migration and suppressed the expression of MMP-2 and μPA. In conclusion, HDP shows suppressive effects against the aggressive phenotypes of human larynx squamous carcinoma cells and may have therapeutic potential for this malignancy.