Borate-fructose complex: A novel mediator for laccase and its new function for fructose determination.

Laccase and borate-fructose complex were investigated by coincidence in a solid-state fermentation of Edenia sp. TS-76 under fructose oxidase screening. Laccase was purified to homogeneity with a 34-fold purification and 32% yield. Fructose had no significant effect on laccase activity, whereas borate reduced laccase activity by 60-90%; conversely, the borate-fructose complex increased laccase activity by nearly fourfold at pH 7.5. The complex caused a shift in the optimal pH for laccase from 5.0 to 7.5 and served as a highly efficient mediator. Borate complexed with fructose provides an alternative, time-saving, and specific method for serum fructose determination.

Curcumin-targeting pericellular serine protease matriptase role in suppression of prostate cancer cell invasion, tumor growth, and metastasis.

Curcumin has been shown to possess potent chemopreventive and antitumor effects on prostate cancer. However, the molecular mechanism involved in curcumin's ability to suppress prostate cancer cell invasion, tumor growth, and metastasis is not yet well understood. In this study, we have shown that curcumin can suppress epidermal growth factor (EGF)- stimulated and heregulin-stimulated PC-3 cell invasion, as well as androgen-induced LNCaP cell invasion. Curcumin treatment significantly resulted in reduced matrix metalloproteinase 9 activity and downregulation of cellular matriptase, a membrane-anchored serine protease with oncogenic roles in tumor formation and invasion. Our data further show that curcumin is able to inhibit the induction effects of androgens and EGF on matriptase activation, as well as to reduce the activated levels of matriptase after its overexpression, thus suggesting that curcumin may interrupt diverse signal pathways to block the protease. Furthermore, the reduction of activated matriptase in cells by curcumin was also partly due to curcumin's effect on promoting the shedding of matriptase into an extracellular environment, but not via altering matriptase gene expression. In addition, curcumin significantly suppressed the invasive ability of prostate cancer cells induced by matriptase overexpression. In xenograft model, curcumin not only inhibits prostate cancer tumor growth and metastasis but also downregulates matriptase activity in vivo. Overall, the data indicate that curcumin exhibits a suppressive effect on prostate cancer cell invasion, tumor growth, and metastasis, at least in part via downregulating matriptase function.