Abstract: Objective  To investigate the effect of hypoxia on the expressions of hypoxia inducible factor-1α (HIF-1α) and differentiated embry-ochondrocyte expressed gene 1 (DEC1) in human gastric cancer cells. Methods  The BGC823 cell lines were divided into the experimental groups (hypoxia for 24 hours group and hypoxia for 48 hours group), the control groups (normoxic for 24 hours group and normoxic for 48 hours group), and the negative control group (PBS instead of the first antibody). The experimental groups were cultured in the hypoxia incubator with 5%CO2 and 0.5%O2, and the control groups were exposed to the normal oxygen condition. The levels of mRNA and protein of HIF-1α and DEC1 were determined by RT-PCR, Western blotting and immunocytochemistry method, and their correlations were analyzed. Results  The expressions of both mRNA and protein of DEC1 and HIF-1α in BGC823 cell lines were upregulated significantly compared with the control groups under the hypoxia condition (P<0.05). With the extension of hypoxia, the mRNA expressions of HIF-1α and DEC1 increased, while the protein expressions of HIF-1α and DEC1 declined. Immune cytochemistry method also showed that the positive expression rates of HIF-1α and DEC1 in the experimental groups were higher than those in the control groups (P<0.05). Conclusion  Hypoxia can induce the expressions of HIF-1α and DEC1, which have significant correlation, in BGC823 cell lines. During hypoxia, HIF-1α protein accumulates and activates the transcription of downstream target gene DEC1, which suggests that DEC1 is a marker of activated hypoxic pathways and plays an important role in hypoxia tolerance in gastric cancer.

Key words: Gastric neoplasm, Hypoxia inducible factor-1α, Hypoxia, Differentiated embry-ochondrocyte expressed gene 1