Figure 3: Systemic p38α/β inhibition affects HNSCC DTC behaviour in growth-restrictive microenvironments. | Nature Cell Biology

Figure 3: Systemic p38α/β inhibition affects HNSCC DTC behaviour in growth-restrictive microenvironments.

From: TGF-β2 dictates disseminated tumour cell fate in target organs through TGF-β-RIII and p38α/β signalling

Figure 3

(a) Representative images of cytokeratin 8/18 (CK), P-H3 (left) and p27 (right) staining in solitary BM DTCs in BM cytospins. Scale bar, 10 μm. Right, graph: percentage of p27 and P-H3 positive DTCs per BM flush. Numbers on top, n for scored DTCs. 6 BM flushes and 3 independent experiments were assessed. (b) Quantification of BM-DTCs in mice treated with dimethylsulphoxide (control) or SB203580 (SB; 10 mg kg−1 every 48 h) for 4 weeks. Left graph: Alu qPCR quantification of BM DTCs shows the human Alu genomic signal normalized to genomic mouse GAPDH (n = 6 (control); 15 (SB) DNA samples were assessed over 3 independent experiments; see methods for details). Right graph: quantification of CK8/18+ cells in mice BM cytospins (n = 6 BM samples per condition were assessed over 2 independent experiments). *P<0.05 by Wilcoxon’s signed rank test. (c,d) Live imaging of HEp3–GFP DTCs, micro and macrometastasis in spleen (c) and liver (d) of control (scale bar, 80 μm) and SB203580-treated mice (spleen, scale bar, 400 μm and liver, scale bar, 80 μm). Numbers, GFP+ cells per organ. (e) Quantification of BM-DTCs in chicken embryos’ BM flushes 5 days after inoculation of T-HEp3–GFP cells transfected with either scrambled (scr) or p38 α siRNAs. (n = 7 (scr siRNA), 6 (p38 α siRNA) BM samples were assessed over 2 independent experiments.) Lower panels: representative fluorescence intravital images of BM DTCs in chicken embryo BM flushes. Scale bar, 160 μm. (f) Graph: percentage of p27+ cells per BM flush (n = 3 BM flushes were assessed over 2 independent experiments). Lower panels: representative images of CK8/18 (right column) and p27 (left column) staining in solitary BM DTCs in chicken embryo BM 5 days after inoculation of T-HEp3–GFP cells transfected with scrambled (scr; upper row) or p38α (lower row) siRNA. Scale bar, 40 μM. Data in a,b and f, represent mean±s.e.m. In b (left graph), e,f, *P<0.05, **P<0.01 by Mann–Whitney test.

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