ABSTRACT
AIM:To explore the effects of neuraminidase 3 (NEU3) on the viability, invasion and apoptosis of human prostate cancer DU145 cells and the molecular mechanism.METHODS:The human prostate cancer DU145 cells were divided into blank control group and treatment group.The cells in treatment group were treated with either neuraminidase inhibitor DANA, or NEU3 small interfering RNA (siRNA) to knock down the expression of NEU3.The cell viability was measured by CCK-8 assay.The cell invasion ability was detected by Transwell assay.The effects of the treatments on the mRNA level of Bcl-2 were detected by q PCR.The effects of the treatments on the protein levels of matrix metalloproteinase 2 (MMP2) and apoptotic inhibitory protein Bcl-2 were determined by Western blot.Apoptosis of the cells was analyzed by flow cytometry.RESULTS:The protein level of NEU3 and the apoptotic rate in DANA group were not significantly different from those in blank control group.The viability of DANA-treated DU145 cells was increased, and the invasion ability, MMP2 protein level, and Bcl-2 mRNA and protein levels were all decreased in these cells, compared with blank control group.On the other hand, the levels of NEU3 protein and Bcl-2 mRNA and protein in NEU3 siRNA group were significantly decreased compared with blank control group, while the viability and apoptotic rate of the cells with NEU3 siRNA transfection were increased (P<0.05).However, the protein expression of MMP2 and the invasion ability of the cells were not significantly changed after NEU3 siRNA treatment.CONCLUSION:The inhibition of NEU3 in enzyme activity and expression decreases the viability, and enhances the apoptosis of human prostate cancer DU145 cells.However, it has no obvious effect on the invasion ability of DU145 cells.
ABSTRACT
Sialic acids are a subset of nine-carbon alpha-keto aldonic acids involved in various biological functions. Sialic acid on the sperm surface is closely related to sperm maturation and capacitation and sperm-egg recognition, which makes sperm negatively charged to avoid accumulation and covers some antigenic determinants there to increase the survival rate of sperm in the female reproductive tract. The loss of sialic acids is an important factor mediating sperm capacitation. Moreover, the sialic acid at the extremity of the protein polymer is involved in signal identification in sperm-egg recognition. Here, we review the current understanding of sialic acids in sperm maturation and capacitation and sperm-egg recognition.