Abstract: Objective To explore the mechanism of hypoxia on SW480 cell autophagy.Methods We screened the CD133+ cell with the characteristics of stem cell by magnetic cell separation. Then the SW480 cell and CD133+ cell were cultivated under hypoxic conditions. Subsequently, we detected the HIF-1α expression by immunofluorescence (IF), LC3 expression by western blot and HIF-2α and Beclin 1 expression in 94 colon cancer tissue samples by immunohistochemistry. Results The results showed that hypoxia induced the activation of HIF-1α in SW480 cell. After hypoxia 24 h, compared with the normal, the LC3 expression was increased in both SW480 cell and CD133+ cell and increased as the processing time increased. The conversion from LC3Ⅰto LC3Ⅱwas increased in CD133+ cell, but decreased in SW480 cell. In olon cancer tissue samples, HIF-2α and Beclin 1 expression in poorly differentiated group were higher than well-differentiated group.HIF-2α expression in no lymph node metastasis group was higher than high lymphatic metastasis group. However the Beclin expression was in the opposite regulation. Conclusion Hypoxia can induce the SW480 apoptosis and a few of CD133+ cell autophagy that can protect the cell from apoptosis by inducing the HIF expression and increasing LC3.

Key words: hypoxia, autophagy, HIF, LC3, CD133+