BM-MSC enhance tumor growth and stimulate lymphangiogenesis <i>in vivo</i>.

<p>(A) <i>In vivo</i> bioluminescent signal of tumors developed following injection of 5×10⁴ LLC-Luc cells alone (n = 30) or mixed with 2,5×10⁵ MSC (LLC+MSC) at day 21 (n = 21). The graph corresponds to the quantification of luciferase activity revealing a strong increase of the signal in the LLC+MSC group. (B) BM-MSC enhance lymphatic vessel density in tumors. Sections of tumors induced by injection of LLC-Luc alone (LLC) or with MSC (LLC+MSC) were immunostained with an anti-podoplanin antibody. A computer-assisted quantification of lymphatic vessel density in LLC-Luc tumors (LLC) or in LLC-Luc tumors mixed with BM-MSC (LLC+MSC) is provided on the right. Bar: 100 µm (C) BM-MSC enhance <i>in vivo</i> lymphatic vessel recruitment in sponge implanted in mice ear. Sponges soaked with control medium (CTR; n = 8) or with MSC conditioned medium (MSC CM; n = 7) were implanted in mice ear between skin and cartilage. Lymphatic vessels were identified by LYVE-1 immunolabeling (green) and nuclei were evidenced with Dapi (blue). Bars: 5 mm and 1,5 mm on magnification. * P<0.05. (D). The graphs correspond to LYVE-1 positive lymphatic vessel quantification expressed as (1) the number of vessels plotted as a function of distance to the sponge edge (top graph), and (2) the number of vessels at a distance of 0.3 mm from the edge of the sponge (bottom graph). * P<0.05.