Irisin對人類神經膠質瘤細胞株U-87 MG之影響

Abstract

Clinical research indicated exercise could prevent cancer and delay cancer progression. Exercise has no side effect, therefore, the mechanism of how exercise affects cancer should be clarified for promoting development of cancer therapy. Previous studies found that exercise induces secretion of irisin from myocytes. Exercise-induced irisin finally targets to white adipocytes, and induces white adipocytes browning to brown-like adipocytes. Browning changes adipokine secretion and increases energy expenditure. Moreover, previous studies indicated white adipocytes also present in tumors and make tumor cells more aggressive. Based on above information, we speculated that exercise-induced irisin may affect cancer cells through inducing browning of cancer-associated adipocytes. First, recombinant irisin protein was produced in E.coli and purified by the Ni-NTA column. The white adipocyte binding and browning ability of the recombinant irisin were confirmed. Next, we investigated the effect of irisin on the human glioblastoma cell line, U-87 MG. After irisin treatment, the cell viability and migration of U-87 MG remained unchanged, but the cell invasion was decreasing. Moreover, the cell migration and invasion of U-87 MG were both decreasing by co-culture with irisin-induced-brown-like adipocytes. Furthermore, with the injection of radio-isotope-labeled irisin into BALB/c nude mice, we found irisin had significant tumor targeting ability by PET imaging. Our results indicated that irisin could significantly inhibit the cell invasion of U-87 MG in both direct and adipocytes-related indirect way. Cell invasion was important for metastasis and the indicator of aggressive cancers. Therefore, our results proposed irisin play the key role of how exercise delay cancer progression.