Csig-14. the impact of corticotrophin releasing hormone stress neuro-hormones on the viability and proliferation of brain tumours

Abstract The majority of brain tumour sub-types are of glial origin. These include high-grade gliomas (HGGs), which lack effective targeted therapies and are thus invariably lethal. We have shown that stress leads to proliferation of brain glia. Such stress-induced glial cell division could provide opportunities for detrimental genetic mutations which increase the risk of oncogenesis. Identifying stress-induced glial plasticity could uncover molecular targets that directly influence glioma viability. Corticotropin-releasing hormone (CRH) stress neurohormones, including urocortin I-III (UCN I-III) are key mediators of stress signalling in the brain including neuroplastic processes. The aims of this project were to compare the expression CRH peptides and receptors in different types of brain tumours and their impact on cells viability and proliferation. Five different brain tumour cell lines were used (two biopsy-derived-in-house-established HGGs – UP007 and SEBTA023 – and three commercially available Medulloblastomas, MBs – UW402, CHLA-01-MED and CHLA-01R-MED). The gene expression profiles of the CRH family were accessed by qRT-PCR (n = 5) and the protein expression by Immunocytochemistry and flow cytometry (FC, n = 3). The effects of targeted drug modulation were assessed through viability (MTS, n = 3) and proliferation assays (Cyquant NF cell proliferation, n = 3). Statistical significance of qRT-PCRs and FC were calculated through a Kruskal-Wallis test, and for viability and proliferation assays through a two-way ANOVA approach. Values of P < 0.05 were accepted as significant. The qRT-PCRs revealed a higher expression of stress neuro-hormones mRNA in MBs compared to HGGs. Immunocytochemistry confirmed the protein expression of CRH and downstream receptors in all cell lines, while FC revealed a higher expression of CRH-Rs in HGGs than MBs. The pharmacological modulation of CRH-Rs induced contrasting effects on cellular viability and proliferation, suggesting patient-specific CRH-CRH-R pathway. This raises the prospect of repurposing available CRH-R ligands for targeted treatment of susceptible tumour types.