Hypoxia is an essential feature of the microenvironment of solid tumors, which regulates a variety of transcription factors including hypoxia-inducible factor-1α (HIF-1α). HIF-1α overexpression enhances tumor angiogenesis via upregulation of vascular endothelial growth factor (VEGF) and some other hypoxia-inducible angiogenic factors, which lead to a more aggressive tumor phenotype, tumor metastasis and resistance to radiation and chemotherapy. In this study, we found that a histone deacetylase (HDAC) inhibitor, trichostatin A (TSA), inhibited cell proliferation and invasion, blocked the cell cycle, and induced cell apoptosis in a dose- and time-dependent manner in the human tongue squamous cell carcinoma (TSCC) SCC-6 cell line in vitro. Furthermore, TSA reduced both basal levels and hypoxia-induced HIF-1α protein accumulation but not HIF-1α mRNA levels, and both protein and mRNA levels of VEGF expression. These results showed that TSA had a potent anticancer activity on TSCC cells, suggesting that TSA could be a promising drug targeting tumor angiogenesis via inhibition of HIF-1α and VEGF expression in the development of an effective chemopreventive and anticancer agent on human TSCCs.

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