RESUMO
<p><b>OBJECTIVE</b>To investigate HIF-1α gene expression in human breast cancer cells and the role of HIF-1 in tumor metastasis and invasion.</p><p><b>METHODS</b>Human breast cancer cell lines were cultured under normoxic or hypoxic conditions. Western blot was used to evaluate the protein expression of HIF-1α, p-vimentin and α-tubulin. Small interfering RNA targeting HIF-1α was used to block the expression of HIF-1α in MDA-MB-231 and SK-BR-3 cell lines. Matrigel transwell and cell wound healing assays were used to detect the capability of cellular invasion and migration, respectively.</p><p><b>RESULTS</b>Under normoxic condition, all the cell lines tested showed a base-level of HIF-1α expression. The highest expression level of HIF-1α protein was obtained in the MDA-MB-231 cell line, which is also noticed to be highly invasive and migratory in behavior. HIF-1α siRNA was capable of blocking the protein expression of both HIF-1α and p-vimentin and in addition, the attenuated ability of invasion and migration.</p><p><b>CONCLUSION</b>Since HIF-1 is able to promote invasion and metastasis of tumor cells, which may be considered as a target in anti-cancer therapy.</p>
