Synergism of Pro-neurogenic miRNAs Provides a More Effective Strategy to Target Glioma Stem Cells

Abstract Background: Tumor suppressor microRNAs (miRNAs) have been explored as agents to target cancer stem cells. Most strategies use a single miRNA mimic and present many disadvantages, such as the amount of reagent required and the diluted effect on target genes. miRNAs work in a cooperative fashion to regulate distinct biological processes and pathways. This information can be used to design more efficient ways to target cancer stem cells via miRNA combinations. Methods: We transfected glioma stem cell and neuroblastoma lines with miRNA combinations and evaluate their impact on cancer relevant phenotypes and neuronal differentiation. RNA-seq analysis was conducted then to determine the expression alterations induced by the miRNA combination and map target genes and affected pathways. Results: We have shown that miR-124, miR-128, and miR-137 function synergistically to regulate neurogenesis. We used a combination of these three miRNAs to treat glioma stem cells. miR-124, miR-128 and miR-137 combined treatment was much more effective than single miRNAs in disrupting cell proliferation and survival and promoting differentiation and response to radiation. Transcriptomic analyses indicated that transcription regulation, angiogenesis, metabolism, and neuronal differentiation are among the main biological processes affected by transfection of this miRNA combination. Finally, in search of other combinations of other tumor suppressor/pro-neurogenic miRNAs, we identified a miRNA cluster based on target predictions and established miR-29, miR-101, and miR-218 combination as an alternative to be used in cancer therapy. Conclusions: We demonstrated the value of using combinations of neurogenic miRNAs to disrupt cancer phenotypes and glioma stem cell growth. Our genomic analyses in GSCs established that the synergistic effect of these three miRNA amplified the repression of oncogenic factors and the effect on cancer relevant pathways. These results suggest that future therapeutic approaches would benefit from utilizing miRNA combinations, especially when targeting cancer-initiating cell populations.