Figure 5. sECM-encapsulated therapeutic human MSCs have anti-tumor effects on primary invasive human GBMs in vitro and in vivo.

(a,b) Primary invasive GBM8-mCherry-Fluc cells grown as neurospheres in a collagen matrix (a) and brain section of mice bearing GBM8-mCherry-Fluc tumors, showing the highly invasive nature of GBM8 (b). Arrow, site of implantation; arrowheads, path of invasion. (c–g) hMSCs expressing GFP or S-TRAIL were encapsulated in sECM and placed in a culture dish containing human GBM8-Fluc-mCherry cells. hMSCs (green) were followed for migration out of sECM, and GBM8 cells (red) were followed for their response to S-TRAIL secreted by hMSCs. Photomicrographs show sECM-encapsulated hMSCs on the day of plating (c,e) and 48 h after plating (d,f). (g) GBM8 cell viability at different time points after culturing with varying numbers of either sECM-encapsulated hMSC-GFP (control) or hMSC-S-TRAIL (TRAIL) cells. *P < 0.05 versus TRAIL at 8 h, 16 h and 24 h. (h–j) Encapsulated hMSC-S-TRAIL or hMSC-GFP cells in sECM were implanted intracranially in the tumor resection cavity of mice bearing GBM8-mCherry-Fluc cells and mice were followed for changes in tumor volume by serial Fluc bioluminescence imaging and correlative immunohistochemistry. Plot and representative images show the relative mean Fluc signal intensity from mice bearing sECM-encapsulated hMSC-GFP or hMSC-S-TRAIL cells. *P < 0.05 versus control (h). (i,j) Low-magnification (i) and high-magnification (j) photomicrographs of serial brain sections of mice showing hMSCs (green) on day 5 after hMSC implantation in the GBM8 (red) resection cavity. (k,l) Representative images showing cleaved caspase-3 staining (purple) on brain sections from mice implanted with hMSC-S-TRAIL cells (green, k) and control cells (green, l) 5 d after treatment. Scale bars: 100 µm (a,c–f,i), 200 µm (b) and 50 µm (j–l). Data are mean ± s.e.m.