TMIC-44. IL-1 ANTAGONIST ANAKINRA INHIBITS GLIOBLASTOMA PROLIFERATION BY ANTAGONIZING THE PROINFLAMMATORY MICROENVIRONMENT

Abstract

Abstract INTRODUCTION The recombinant IL-1 receptor antagonist anakinra prevents binding of IL-1 to its receptor and blocks IL-1β-mediated proinflammatory signaling. It is currently used in the treatment of autoinflammatory diseases. As inflammation is a major driver of malignancy, we hypothesized that anakinra – by ameliorating the inflammatory tumor environment – might be capable to mitigate glioblastoma (GBM) progression. METHODS T98G GBM cells were cultivated with PBMC, separated by cell culture inserts with or without anakinra and incubated 48h in 5% O2 mimicking the GBM microenvironment. T-cells were obtained by magnetic bead isolation. mRNA expression levels were measured by quantitative Real-Time-PCR (qRT-PCR). Cytokine production was assessed by ELISA. Cell proliferation was analyzed by flow cytometric quantification of Ki-67 protein expression. Anakinra has been provided by Swedish Orphan Biovitrum AB (Sweden). Results are presented as mean±SEM, p-Values were calculated using Student’s t-test. RESULTS After administration of anakinra, mRNA expression levels of the inflammatory and proangiogenic genes IL-1β, COX-2, CCL2 and IL-8 were reduced in T98G (-64%±19.1%, -56.2%±21.3%, -87.1%±28.8%, -91.7%±27.2%, n=7, p< 0.05). Surprisingly, no changes of these targets were detectable in PBMC. However, in T-cells, anakinra induced mRNA expression of Th2 transcription factor GATA3 and the antiinflammatory cytokines IL-4 and IL-10 (+6,7%±4,6%, +36,1%±22,9%, +69,1%32,8%, n=10, p< 0.05). The expression of the protumorigenic genes IL-22, IL-17 as well as IFNγ was dramatically repressed (-63.2%±21.9%, -88.1%±21.7%, -85.6%±45.2%, n=10, p< 0.05), protein secretion of IL-22 and IFNγ was strongly blocked (-36.3%±9.1%, -13.9%±0.5%, n=6, p< 0.05). Importantly, treatment with anakinra markedly attenuated GBM cell proliferation (-20.1%±5%, n=4, p< 0.05). CONCLUSION Anakinra indeed puts the brake on proinflammatory signaling pathways in GBM cells and simultaneously promotes a shift towards an anti-inflammatory T-cell phenotype. As a result, GBM proliferation is diminished. Hence, administration of anakinra might be an interesting and novel therapeutic approach to reduce Glioblastoma aggressiveness.