Serum core-type fucosylated prostate-specific antigen index for the detection of high-risk prostate cancer.

It is known that core-type fucosylation is higher in prostate cancer cells than in other cancer cell types and is associated with high-risk prostate cancer. Here, we developed an automated microcapillary electrophoresis-based immunoassay system for measuring serum core-type fucosylated prostate-specific antigen (PSA) and evaluated whether the serum fucosylated PSA index (FPI) can detect high-risk prostate cancer. Core-type fucosylated-free PSA was measured by our automated microcapillary electrophoresis-based immunoassay system with Pholiota squarrosa lectin. The FPI was calculated from total PSA and the percentage of fucosylated-free PSA. The optimum model to predict Gleason grade (GG) ≥2 was constructed by multivariate logistic regression analysis. Discrimination was assessed by determining the area under the receiver operator characteristic curve (AUC). The study included 252 men who underwent prostate needle biopsy due to elevated serum PSA levels (4-20 ng/mL), including 138 with GG ≥2. A higher FPI was significantly associated with GG (P < .0001). Multivariate logistic regression analysis showed that age, prostate volume and FPI were significant predictors of GG ≥2. The AUC of FPI and the model were 0.729 (95% confidence interval [CI]: 0.668-0.790) and 0.837 (95% CI: 0.788-0.886), respectively, compared to 0.629 (95% CI: 0.561-0.698) for PSA. Decision curve analysis showed the superior benefit of FPI and the model when compared to PSA. In a cohort with serum PSA levels <20 ng/mL, FPI could differentiate high-risk prostate cancer from biopsy-negative or low-risk prostate cancer. Therefore, FPI could be a useful adjunct in prostate biopsy counseling for men with abnormal PSA levels.

The need of MMP-2 on the sperm surface for Xenopus fertilization: its role in a fast electrical block to polyspermy.

Monospermic fertilization in the frog, Xenopus laevis, is ensured by a fast-rising, positive fertilization potential to prevent polyspermy on the fertilized egg, followed by a slow block with the formation of a fertilization envelope over the egg surface. In this paper, we found that not only the enzymatic activity of sperm matrix metalloproteinase-2 (MMP-2) was necessary for a sperm to bind and/or pass through the extracellular coat of vitelline envelope, but also the hemopexin (HPX) domain of MMP-2 on the sperm surface was involved in binding and membrane fusion between the sperm and eggs. A peptide with a partial amino acid sequence of the HPX domain caused egg activation accompanied by an increase in [Ca(2+)]i in a voltage-dependent manner, similar to that in fertilization. The membrane microdomain (MD) of unfertilized eggs bound the HPX peptide, and this was inhibited by ganglioside GM1 distributed in the MD. The treatment of sperm with GM1 or anti-MMP-2 HPX antibody allows the sperm to fertilize an egg clamped at 0 mV, which untreated sperm cannot achieve. We propose a model accounting for the mechanism of voltage-dependent fertilization based on an interaction between the positively charged HPX domain in the sperm membrane and negatively-charged GM1 in the egg plasma membrane.