P01.04 Adult and paediatric GBM cells show differential phenotypic responses to external lipoprotein deprivation

Abstract

AbstractIntroduction:Glioblastoma multiforme (GBM) is a highly aggressive CNS neoplasm histologically characterised by mitotic atypia and microvascular proliferation. Aberrant activation of angiogenesis during tumour growth results in an improperly formed tumour vasculature, leading to gradients of oxygen and nutrients within the tumour microenvironment. Transport of lipids in blood is mediated via lipoprotein complexes. Adult GBM cells demonstrate a preferential uptake of lipoproteins to meet metabolic demands over de novo lipid synthesis. We investigated the growth and morphological responses of paediatric GBM cells under lipoprotein-deplete conditions.Materials and Methods:Two paediatric GBM cell lines (KNS42 and SF188) and one paediatric grade I pilocytic astrocytoma (Res186) cell line were cultured under lipoprotein-replete and –deplete conditions over 7 days. Cell viability was quantitatively assessed using the resazurin-based PrestoBlue reagent and was complemented with qualitative cell density assessment through crystal violet staining. Experiments were repeated using the adult GBM U87 cell line and patient-derived tumour cells (GIN-8) isolated from the invasive margin of an adult GBM.Results:Cell viability and density assays revealed reduced exponential growth rates of KNS42 and SF188 cells grown in lipoprotein deficient media compared to cells cultured under lipoprotein-replete conditions. In contrast, Res186, U87 and GIN-8 cells demonstrated cytostatic growth patterns after 3 days culture under lipoprotein-deplete conditions. Accompanying the growth responses of Res186 and U87 cells were morphological changes reminiscent of differentiation (process elongation), a phenotype not observed for KNS42 and SF188 cells.Conclusions:Evaluation of growth under lipoprotein–deplete conditions revealed an enhanced capacity of paediatric GBM cells to proliferate under acute metabolic stress compared to adult GBM and grade I paediatric glioma cells. This is likely reflective of differences at the genetic level and/or respective cell-of-origin. We will discuss metabolomic and transcriptomic strategies identifying signalling pathways mediating adaptive responses to metabolic stress that will be assessed in 3D culture models. Growth of GBM cells under lipoprotein-deplete conditions likely recapitulates selective pressures within the tumour microenvironment in vivo, revealing essential metabolic pathways that will inform next-generation targeted treatment strategies.