(a) Confocal sections of human SCCs stained with SOX2
(green), Survivin (SURV, red), α6-integrin (α6, white) and DAPI
(blue). Scale bars indicate 10 µm. (b–c) Radial
histograms indicating the orientation of basal cell divisions relative to the
tumor-stroma interface expressing high (green) or low (red) levels of SOX2 in
human (b) and mouse (c) SCCs. Blue lines indicate
median division angles. (d) Projections of representative
three-dimensional immunofluorescence micrographs of shSCR;H2B-GFP and
shSOX2;H2B-RFP clones in A431 xenografts stained with Survivin (SURV, white),
α6-integrin (blue). Scale bars indicate 10 µm.
(e–f) Radial histograms describe the orientation of
basal cell divisions relative to the tumor-stroma interface in shSCR;H2B-GFP
(green) and shSOX2;H2B-RFP (red) clones in human (e) and mouse
(f) SCC transplants. Blue lines indicate median division
angles. (g–h) Flow cytometric analyses of shSCR;H2B-GFP and
shSOX2;H2B-RFP clonal competition assays two weeks after transplantation.
(g) Scatter plots illustrate the relative abundance of
shSCR;H2B-GFP and shSOX2;H2B-RFP cells within the α6/β1-integrin
high and low gates. (h) Bar graphs show mean population size of
shSOX2;H2B-RFP and shSCR;H2B-GFP expressing cells within the
α6-integrin-high and α6-integrin-low gates with error bars
indicating ± s.d (n=6, *P<0.05, Student’s t-test).