Abstract: Objective  To investigate the effect of short hairpin RNA （shRNA） targeted silencing of α2， 8-sialyltransferase 4 （ST8SIA4） gene on invasion and migration of breast cancer BT549 cells. Methods  Real-time quantitative PCR （QPCR） and Western blotting were used to detect the mRNA and protein levels of ST8SIA4 in BT549 cells and MCF-10A cells. BT549 cells were randomly transfected with the successfully constructed shRNA vector fragments targeting ST8SIA4 gene （silencing group） or nonsense shRNA fragments （control group） via LipofectamineTM 2000. ST8SIA4 mRNA expression was detected after 48 h transfection by QPCR. The expressions of ST8SIA4， phosphorylated Akt （p-Akt）， neuropilin2 （NRP2） and tumor necrosis factor-α （TNF-α） were detected by Western blotting. The invasion and migration abilities of cells were detected by Transwell assay and scratch assay， respectively. Results Compared with MCF-10A cells， the relative expression level of ST8SIA4 mRNA and protein in BT549 cells increased significantly （P＜0.05）. After 48 h transfection， the mRNA and protein levels of ST8SIA4 in the silencing group were 0.19±0.02 and 0.13±0.02， lower than 0.98±0.11 and 0.52±0.05 in the control group （P＜0.05）. The number of invasive cells， migration rate and relative expressions of p-Akt， NRP2 and TNF-α were 39.5±4.2， （16.9±1.3）％， 0.22±0.03， 0.31±0.04 and 0.27±0.06 in the silencing group， all lower than 91.3±8.5， （38.4±3.9）％， 0.58±0.07， 0.55±0.05 and 0.46±0.05 in the control group（P＜0.05）. Conclusion  ST8SIA4 gene is highly expressed in breast cancer BT549 cells. Silencing its expression may inhibit invasion and migration， which may be related to up-regulation of p-Akt， NRP2 and TNF-a protein expression.

Key words: ；α2')"> Breast cancer；α2, -sialyltransferase 4；Invasion；Migration')"> 8-sialyltransferase 4；Invasion；Migration