Human neural stem cells repress glioma cell progression in a paracrine manner by downregulating the Wnt/β‐catenin signalling pathway

Abstract

Neural stem cells (NSCs) play crucial roles in neurological disorders and tissue injury repair through exerting paracrine effects. However, the effects of NSC‐derived factors on glioma progression remain unclear. This study aimed to evaluate the effects of human NSC‐conditioned medium (NSC‐CM) on the behaviour of glioma cells using an in vitro co‐culture system. Cell counting kit‐8 and 5‐ethynyl‐2′‐deoxyuridine assays revealed that NSC‐CM inhibited glioma cell proliferation and growth in a fetal bovine serum (FBS)‐independent manner. In addition, our wound‐healing assay demonstrated that NSC‐CM repressed glioma cell migration, while results from transwell and 3D spheroid invasion assays indicated that NSC‐CM also reduced the invasion capacity of glioma cells. Flow cytometry showed that NSC‐CM prevented cell cycle progression from the G1 to S phase and promoted apoptosis. Western blotting was used to show that the expression of Wnt/β‐catenin pathway‐related proteins, including β‐catenin, c‐Myc, cyclin D1, CD44 and Met, was remarkably decreased in NSC‐CM‐treated glioma cells. Furthermore, the addition of a Wnt/β‐catenin pathway activator, CHIR99021, significantly induced the expression of β‐catenin and Met and increased the proliferative and invasive capabilities of control medium‐treated glioma cells but not those of NSC‐CM‐treated glioma cells. The use of enzyme‐linked immunosorbent assays (ELISA) revealed the secretion of some antitumour factors in human and rat NSCs, including interferon‐α and dickkopf‐1. Our data suggest that NSC‐CM partially inhibits glioma cell progression by downregulating Wnt/β‐catenin signalling. This study may serve as a basis for developing future antiglioma therapies based on NSC derivatives.

Keywords

• conditioned medium
• glioma
• human neural stem cells
• invasion
• proliferation