Tumor cell lipid loading promotes paracrine activation of vascular cells and macrophages. See Fig. 4a for a schematic overview of functional assays with conditioned medium (CM) isolated from GBM cells (U-87 MG or GL261) grown in serum-free (SF) medium without and with extracellular lipid (+LDL) in normoxia (N) or hypoxia (H). A, HBMECs were assessed for transwell migration over a period of 6 h towards SF medium (CTRL) and the various GL261 CM variants, as indicated. LDL = SF medium supplemented with LDL. B, HBMECs were cultured for 72 h at the same conditions as described in (A) and assessed for cell proliferation. C, Human derived monocytes differentiated into macrophages (THP-1) were assessed for transwell migration over a period of 6 h towards the same media conditions as described in (A and B). A-C, Data are presented as the mean fold of untreated (CTRL) ± SD from at least three independent experiments. (PDF 12 kb)