esiRNA Mediated Silencing of HIF1A Regulates Migration, Invasion, Apoptosis, and Proliferation of MDA-MB-231 Cells

This study demonstrated that silencing of HIF1A using esiRNA (endoribonuclease prepared small interfering RNA) could inhibit breast cancer cells proliferation, increase the apoptosis rate, and inhibit cell invasion and migration. These results suggested that HIF1A gene may involve in the occurrence and development of triple negative breast cancer phenotype. Hypoxia is an important hallmark of most solid tumors. In breast cancer, hypoxia is more evident in TNBC (triple negative breast cancer) than in other breast cancer subtypes. Intratumoral analysis in TNBC showed that tumor areas with high levels of hypoxia, indicated higher expression of HIF1A. Here we investigated the effect of silencing HIF1A on the biological function of triple negative breast cancer. Reverse transcription-polymerase chain reaction and western blot were used to detect HIF1A expression in different breast cancer cells and patient tissues. esiRNA was used to silence HIF1A in MDA-MB-231 cells. Then, BrdU assay was performed to study cell proliferation. Additionally, cell apoptosis after HIF1A knockdown was measured by Annexin V/propidium iodide staining followed by Caspase assay, and cell migration and invasion was detected by trans-well assay. IHC analysis suggested a strong overexpression of HIF1A in TNBC tissues. Silencing suggested that HIF1A significantly promotes cell proliferation and migration, resulting in metastasis and downregulates apoptosis. MDA-MB-231 cells in which HIF1A expression was inhibited were less invasive, with reduced resistance to hypoxia, impaired migration, increased apoptosis and reduced capacity to cause metastasis. HIF1A may be a dominant factor driving the metastatic progression and apoptosis of triple negative breast cancer and can be a potent therapeutic target for the disease.