Figure 5.

Fibulin-2 and CSF1 are reduced in α3β1-deficient tumors. K14CreERT:α3flx/flx mice were subjected to two-step tumorigenesis then treated with 4OHT or vehicle, as in Figure 1e. (a) Cryosections stained with anti-fibulin-2. t, tumor cells; s, stroma; dashed line, tumor-stroma boundary; scale bar, 100 μm. (b) Quantified fibulin-2 MFI in 4OHT-treated papillomas, normalized to vehicle (dotted line); n≥13 papillomas per group, per timepoint. Mean +/− s.e.m.; two-tailed t-tests; *P<0.05. (c,d) ISH of cryosections from treatment day 14. Representative images for (c) fibulin-2 mRNA (green) or (d) CSF1 mRNA (purple); DAPI (blue) marks nuclei; scale bar, 25 μm. Pie charts, blind-score distribution (n≥8). Image scores: (c) Vehicle, #4; 4OHT, #2; (d) Vehicle, #3; 4OHT, #1. (e) Model: α3β1 regulates secreted factors from tumor cells that promote a pro-tumoral TME.