Effect of a CXCR4 chemokine receptor antagonist on the viability and invasion of glioblastoma cells in organoids

Glioblastom (GBM) je najpogostejši in najagresivnejši primarni možganski tumor pri odraslem človeku. Heterogenost in mikrookolje GBM sta ključna za razvoj in odpornost GBM na klasično zdravljenje. Pomembne komponente mikrookolja tumorja so topne signalne molekule kemokini. Iz stromalnih celic pridobljen faktor 1 α (SDF-1α) je kemokin, ki z vezavo na receptor CXCR4 pospeši angiogenezo tumorja ter migracijo, invazijo in proliferacijo tumorskih celic. Poleg tega vezava SDF-1α na receptor CXCR4 sproži infiltracijo imunskih celic v tumorsko maso. Sintetski antagonist receptorja CXCR4 pleriksafor se tako že uporablja za zdravljenje različnih rakavih obolenj. Da bi raziskali učinek pleriksaforja na GBM, smo vzpostavili organoidni model iz tumorskih biopsij. Model vključuje mikrookolje tumorja, ki je zelo podobno mikrookolju tumorja v bolnikih z GBM. Potrdili smo prisotnost in kolokalizacijo receptorja CXCR4 in njegovega liganda SDF-1α v tumorjih in organoidih GBM na proteinskem nivoju. V vzpostavljenem organoidnem modelu smo z ligacijskim testom bližine dokazali, da pleriksafor v organoidih GBM zmanjša interakcije med CXCR4 in SDF-1α tako sam, kot v kombinaciji s temozolomidom. Pokazali smo, da pleriksafor in pleriksafor v kombinaciji s temozolomidom nima statistično pomembnega učinka na viabilnost in invazijo organoidov GBM. Razlog je lahko v kompleksnosti mikrookolja in aktivaciji drugih signalnih poti, ki so še slabo raziskane. Prihodnje raziskave bomo usmerili v analizo večjega števila tumorskih vzorcev.Glioblastoma (GBM) is the most common and aggressive primary brain tumour in adult humans. Heterogeneity and tumour microenvironment of GBM are crucial for progression and therapeutic resistance of GBM. Key tumour microenvironment components are soluble signalling molecules chemokines. Stromal cell-derived factor 1α (SDF-1α) is a chemokine, which after binding to CXCR4 receptor accelerates tumour angiogenesis, migration, invasion, and proliferation of tumour cells. The binding of SDF-1α and CXCR4 also induces infiltration of immune cells into the tumour mass. The antagonist of CXCR4 receptor plerixafor is currently already in clinical use for treating different cancers. To analyse the effect of plerixafor on GBM, we established an organoid model from tumour biopsies of patients with GBM. GBM organoid includes the tumour microenvironment, which is similar to the tumour microenvironment in the patient. We confirmed the presence and colocalization of the CXCR4 receptor and SDF-1α ligand in the tumour and GBM organoids at protein level. Using Proximity ligation assay we showed, that plerixafor alone and in combination with temozolomide decreases interactions between CXCR4 receptor and SDF-1α in GBM organoids. We also showed that plerixafor alone and in combination with temozolomide doesn’t have a statistically significant effect on viability and invasion of GBM organoids. The cause could be in the complexity of the tumour microenvironment and activation of alternative signalling pathways. A future studies are directed towards analyses of higher number of tumour samples