Abstract 1113: Mir-194-3p suppresses tumorigenic potential of glioblastoma stem cells by targeting the canonical NF-kB pathway

Abstract

Abstract Glioblastoma (GBM) is the most common tumor of the central nervous system, with its deadly nature owing to high rates of invasion and angiogenesis. A key element in its pathogenesis is a small subpopulation of neoplastic cells called glioma stem cells (GSCs) that are responsible for tumor initiation, maintenance and relapse. Approaches to target GSCs have mostly proved futile due to their chemo- and radio-resistance potential. Given that microRNAs carry a potential to affect both normal and stem cells, we employed a microRNA-based targeted approach to identify the subset of microRNAs that could distinctively affect the stemness of GSCs. Our study tests the hypothesis that GSCs will show an altered miRNA expression upon their differentiation, and their profiling may lead to identification of specific microRNAs that regulate the process. Our initial efforts resulted in identification of hsa-miR-194-3p as one of the potential candidates, which was consistently downregulated in multiple GSCs that we investigated. Stable cell lines overexpressing hsa-miR-194-3p showed a decreased proliferation rate and reduced sphere-forming ability. In silico analysis revealed TAB2, an upstream activator of NF-κB pathway to be the potential target of hsa-miR-194-3p, which was confirmed by luciferase assay and knockdown approaches. The regulatory role of hsa-miR-194-3p was substantiated by its ability to inhibit the NF-κB pathway and the corresponding downstream targets including IL-6 and STAT3. In vivo studies revealed a reduced tumor forming ability when the cell lines overexpressing hsa-miR-194-3p were injected intracranially in NOD/SCID mice, compared with the non-target control. Our results indicate that hsa-miR-194-3p blocked the canonical NF-κB signaling and negatively affected tumor formation. We have carried out this study this in a unique model system expecting it to uncover another layer of complexity that may add a new facet to meet the challenge imposed by the cancer stem cell paradigm. In conclusion, we accentuate the anti-tumorigenic role of hsa-miR-194-3p as a connecting link to both stemness and NF-κB signaling. Funding sources: This work was supported by R01CA108633 (To AC), 1RC2CA148190 (To AC) U10CA180850-01 (To AC), 1R01CA169368 (To AC) from the National Cancer Institute (NCI), Brain Tumor Funders Collaborative Grant (To AC), Ohio State University Comprehensive Cancer Center Award (To AC). Citation Format: Rajbir Singh, Kamalakannan Palanichamy, John R. Jacob, Arnab Chakravarti. Mir-194-3p suppresses tumorigenic potential of glioblastoma stem cells by targeting the canonical NF-kB pathway. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1113.