Fig. 8
sEV-VEGF is not neutralized by bevacizumab in vivo and is associated with disease progression in bevacizumab-treated cancer patients. a–e Nude mice were inoculated i.p. with GFP-expressing ES2 VEGF−/− cells. At 7 days thereafter when tumors were palpable, mice were randomized into groups (n = 6 mice per group) and then administered sEVs of ES2 VEGF+/+ cells in combination with either normal human IgG (negative control) or bevacizumab, or rVEGF189 in combination with either normal human IgG or bevacizumab, three times a week for 2 weeks. In a, representative images of GFP-expressing tumors in the abdominal cavity. Arrows indicate tumors on the omentum. Scale bar = 10 mm. In b, immunofluorescence staining of CD31 (red) in sections of omental tumors (Ome T) adjacent to the pancreas (Panc). Scale bar = 100 μm. Amount of i.p. tumor burden (c), numbers of intratumoral CD31+ cells (d) and volume of ascites (e) in each mouse in control (Cont) and bevacizumab (Bev) treatment groups. ***P < 0.001, ****P < 0.0001, by two-sided unpaired t-test. f, g Baseline plasma levels of total VEGF (f) and sEV-VEGF (g) in 17 patients with newly diagnosed metastatic renal cell carcinoma, who were treated presurgically with single-agent bevacizumab for 8 weeks and thereafter restaged. P-values were determined by Mann–Whitney U-test. Source data used for graphs in c–g can be found in Supplementary Data 7
