Objective      To determine the role of hypoxia-inducible factor-1alpha (HIF-1α) on aerobic glycolysis and cell growth in SHG44 cells using siRNA silencing HIF-1α.       Methods      CoCl

2

was used to mimic hypoxia; siRNA technique was used to silen

ce HIF-1α in SHG44 cells. SHG44 cells were divided into 4 groups

including normal culture group

hypoxia culture group

negative control group and HIF-1α siRNA group. Each group was further divided into 2 subgroups

normal glucose intensity group (2 g/L) and high glucose intensity group (5 g/L). The expression of HIF-1α and glycolysis enzymes was measured by real-time PCR and Western blot analysis. Intracellular ATP levels were measured by bioluminescence assay. Cell viability was measured by MTT assay. Apoptotic and death cells and intracellular reactive oxygen species (ROS) were detected by flow cytometry. The alteration of transmembrane potential of mitochondria was determined by confocal laser scanning microscopy.       Results      Under hypoxia

the efficiency of siRNA silencing HIF-1α gene reached to 71%. The mRNA and protein levels of HIF-1α

PKM2

PDK1 and LDHA in the hypoxia culture group were significantly higher than those of normal culture group. Tumor cells showed higher proliferation rate and increased necrosis and apoptosis rate than the cells under normal culture. Moreover

tumor cells had lower intracellular ATP concentrations and elevated mitochondrial membrane potential (all

P

<

0.05). The growth inhibition ratio of cells in HIF-1α siRNA group was significantly higher than that of other groups including hypoxia culture group and negative control group (all

P

<

0.05). The levels of glycolytic enzymes PKM2

PDK1 and LDHA in HIF-1α siRNA group were significantly lower than those of hypoxia culture group and negative control group (

P

<

0.05). Treatment with HIF-1α siRNA decreased the elevated mitochondrial membrane potential in cancer cells

which was also associated with a sharp decrease in intracellular ATP level.       Conclusion      Aerobic glycolysis of cancer cells may contribute directly to carcinogenic progression and malignant transformation by promoting the expression of HIF-1α-regulated genes under hypoxic conditions. HIF-1α gene silencing aggravates

growth inhibition and necrosis of SHG44 cells under hypoxia.