Interferon-Beta Inhibits Human Glioma Stem Cells Rather Than Neural Stem Cells via Cell Cycle and Immune Signaling

Background: Malignant Glioma is considered to be a highly heterogeneous brain tumor, which may have originated from mutated neural stem cells (NSCs) many years before it was diagnosed. Malignant Glioma is characterized by strong self-renewal potential and immature differentiation potential. The main reason is that malignant glioma holds a key cluster cells, glioma stem cells (GSCs). GSCs contribute to tumorigenesis, tumor progression, recurrence, and treatment resistance. Interferon-beta (IFN-β) is well known for its anti-proliferative efficacy in diversity cancers. IFN-β also displayed potent antitumor results in malignant glioma. IFN-β treatments administered in response to gliomas affect both GSCs and NSCs. However, the function comparison, similarities and differences of IFN-β on GSCs and NSCs are rarely reported. MethodsWe used human GSCs and NSCs to detect the response difference between two cells by IFN-β. Human GSCs were constructed by ourselves and human normal NSCs line were differentiated from human embryonic stem cells. Various concentrations of IFN-β were separately used to treat human GSCs (hGSCs) and human NSCs (hNSCs). Cell morphology, growth, expression of special stemness genes, neural-related makers or proliferation related genes were staining and observed, such as SRY-box transcription factor 2 (Sox2), S100 calcium binding protein B (S100-beta) and marker of proliferation Ki-67 (Ki67). Genetic alterations were carefully analyzed by RNA-seq. We used repetitive stimulation treatment and compared the different response between hGSCs and hNSCs with IFN-β. Genomic analysis was also performed to identify genes with changes in expression levels in hGSCs but stable expression levels in hNSCs. ResultsWe found that IFN-β preferentially inhibited GSCs rather than NSCs. The cell body and nucleus size of GSCs increased after IFN-β treatment. The expression of special stemness gene Sox2 and marker of proliferation Ki67 significantly decreased. S100-beta, which was a central nervous system enrichment, cycle progression and differentiation related gene, also reduced after IFN-β treatment. Significant differences were observed between hGSCs and human NSCs after continuous IFN-β treatment. Genomic analysis revealed the enrichment of the immune response, cell adhesion, cell cycle, and ribosome pathways such as proto-oncogene NF-kB subunit ( RELB ), TRAF interacting protein with forkhead associated domain ( TIFA ), nuclear factor kappa B subunit 1 ( NFKB )and signal transducer and activator of transcription 6 ( STAT6 ). Several typical cyclin genes, including cyclin A2 ( CCNA2) , cyclin B1 ( CCNB1) , cyclin B2 ( CCNB2) , and cyclin D1 ( CCND1) , were significantly downregulated in GSCs after IFN-β stimulation. ConclusionsOur study revealed how genetic diversity resulted in differential effects in response to IFN-β treatment. These results may contribute to improve the applications of IFN-β anti-cancer immunotherapy. In addition, these results may also help to design more effective pharmacological strategies to target killing cancer stem cells while protecting normal neural stem cells.