Objective：To investigate the mechanisms and relationship between HIF-1α and CDX2 expressions in human colonic cancer cell line SW480 and LS174T during different time of hypoxia.
Methods：(1)The two tumor cell lines (SW480 and LS174T) were respectively exposed to CoCl2 (100,150 and 200 μmol/L) for different time periods (24 h,36 h and 48 h), and cells viability and proliferation were detected by MTT methods in order to select suitable CoCl2 concentration. (2) Semiquantitative RT-PCR were used to detect the change in mRNA level of SW480 and LS174T under CoCl2 (100μmol/L). Total amounts of CDX2 protein in SW480 and LS174T were examined by Western blot.
Results：Higher concentrations of CoCl2 (150, 200μmol/L) significantly decreased cell survival rate (P＜ 0.05). So, we selected low concentration of CoCl2 (100μmol/L) to construct hypoxic model. HIF-1α mRNA expression of SW480 and LS174T increased with prolongation of hypoxia time when cells were exposed to CoCl2 (100μmol/L) and reached peak at 24 hours hypoxia (P＜0.05). Similar results were observed in Snail mRNA expression. But mRNA and protein expression of CDX2 reduced significantly under CoCl2 (100μmol/L) and gradually declined as the time of hypoxia was prolonged.
Conclusions：HIF-1α might be up-stream regulator of CDX2 and its over expression may play an important role in progression of colorectal cancer.