Aquaporin‐9 expression in malignant glioma

Abstract

Recent studies described enhanced expression of the water channel aquaporin 9 (AQP9) in biopsies of glioblastoma patients. This may indicate a function for AQP9 in glioma progression as water channels are known to contribute to cell migration. Furthermore, AQP9 is a glycerol and lactate channel and could play a role in the energy metabolism of malignant glioma cells.Glial tumors usually consist of several cell types, including malignant glial cells, endothelial cells, microglia and other cells of the immune system. Currently, the specific cellular localization of AQP9 has not been determined. The aim of our studies was to determine the cellular expression of AQP9 in glioblastoma biopsies. Furthermore, we are currently investigating the cellular expression of AQP9 in various murine models of glioblastoma.Human tissue revealed positive AQP9 labeling in a subpopulation of tumor cells. Moreover, we discovered strong immunolabeling of AQP9 co‐localized with the neutrophil marker CD15. Similar to the situation in human tumors, AQP9 was expressed in neutrophils invading murine Gl261 derived tumors. However, Gl261 derived cells did not express AQP9.We conclude, that AQP9 is expressed in human glioma cells and tumor associated neutrophils. Furthermore, the Gl261 murine model of glioblastoma may be suitable to study a function of AQP9 in tumor associated neutrophils.Study supported by Lundbeck Foundation