Effect of hypoxia inducible factor-1α gene silencing on glycolysis correlated gene expression in BxPC-3 cell line

Objective To investigate the impact of hypoxia inducible factor (HIF)-1α gene silencing on glycolysis correlated gene expression in human pancreatic cancer cell line (BxPC-3) under hypoxic conditions.Methods The siRNA was synthesized to silence the expression of HIF-1α in BxPC-3 cell line.The transfected cells were divided into three groups:blank control group (BxPC-3),empty plasmid vector transfection group (GFP) and HIF-1α gene silencing group (sh-HIF-1α).All cells were cultured under either normoxic (21.0％ O2) or hypoxic (0.5％-1.0％ O2) conditions for 48 h.Then pyruvate dehydrogenase kinase 1 (PDK-1),lactate dehydrogenase A (LDH-A),and citrate synthase (CS) expression and the lactate acid level were analyzed respectively.Results Under hypoxic conditions,the expression of HIF-lα mRNA was increased by 12.4％ and HIF-1α protein increased by 1.6 folds correspondingly,which were significantly lower than in BxPC-3 and GFP groups (P ＜ 0.05).PDK-1 and LDH-A expression levels were also lower in sh-HIF-1α group than the other two control groups.Accordingly,the final product of glycolysis,lactate acid level in sh-HIF-lα group [(4.8 ±0.3) nmol/106 cells] was less than in BxPC-3 group [(9.1 ± 0.5) nmol/106 cells] and GFP group [(9.2 ± 0.5) nmol/106 cells] (P ＜ 0.05).In contrast,the expression levels of CS mRNA and protein in BxPC-3 and GFP groups were repressed and lower than in sh-HIF-1α group (P ＜ 0.05).Conclusion Hypoxia would induce HIF-1α expression in BxPC-3 cell line,which upregulated the glycolysis correlated PDK-1 and LDH-A expression.Gene silencing of HIF-1α could inhibit PDK-1 and LDH-A,and promote the CS expression.As a result,the glycolysis pathway was greatly attenuated under hypoxic conditions. Key words: Hypoxia inducible factor-1α;  Glycolysis;  Pyruvate dehydrogenase kinase 1; Lactate dehydrogenase A ;  Citrate synthase