RNA-based modulation of myeloid cell immunosuppression to improve immunotherapy in a Glioblastoma model

Glioblastoma (GBM), a grade IV glioma, is amongst the most aggressive and resistant brain tumours. Nowadays, the standard of care treatment for this tumour is maximal surgery resection, chemotherapy with Temozolomide and radiotherapy (RT). Immunotherapeutic approaches, like the use of immune check point inhibitors has not produced satisfactory results. Our team is part of a European project called “RAIN” that investigates a rather novel approach to increase the efficacy of immunotherapy in glioblastoma. This approach focuses on using RNA-loaded nano systems aimed at reducing the immunosuppression exerted by the myeloid compartment of glioblastoma and increasing the cytotoxicity of effector T cells. Our role in this European consortium is to validate the role of some candidate targets in myeloid-related immunosuppression in GBM, transfer siRNA-loaded-nanoparticles (NPs) in the resection cavity of preclinical glioblastoma model, and investigate their effect on the tumour microenvironment (TME). Our team has previously selected 4 target genes. In this thesis work, I have been involved in testing the effects of silencing these genes in BM-MDSCs with the aim of guiding the formulation of RNA-loaded NPs from another partner of the RAIN consortium. I contributed to the optimization of transfection protocols in BM-MDSC using commercial siRNA and the validation of the effects of these siRNAs on the immunosuppressive activity of myeloid cells on T cell proliferation in vitro.