A paracrine activin A-mDia2 axis promotes squamous carcinogenesis via fibroblast reprogramming (2020)
Figure 1

Figure 1. Activin A promotes squamous cell malignancy and tumor growth in a xenograft model and in organotypic culture

A qRT-PCR for INHBA relative to RPL27 using RNA from SCC13 cells transduced with a lentiviral vector allowing expression of INHBA in a doxycycline (DOX)-inducible manner (SCC13 Act clone 1 and 2) or empty vector (EV) (N=3). SCC13 Act and EV cell lines were generated from lentivirally transduced cells upon single cell clonal expansion.

B Western blot of cell lysate and conditioned media (CM; bottom) of transduced SCC13 cells for the activin βA subunit and GAPDH (loading control for cell lysate) under reducing conditions. The higher molecular weight of recombinant activin βA results from the HA-epitope tag. Ponceau S staining of the membrane was used as a loading control for the CM.

C Representative pictures of 5 week-old tumors (indicated by arrows) formed in NOD/SCID mice upon intradermal injection of SCC13 Act (clone 2) or SCC13 EV cells and tumor volume at different time points of tumor development. N=3-6 tumors.

D Representative images of H&E stainings of tumors formed by SCC13 EV and Act cells (clone 2) at day 35 (asterisk indicates cartilage, arrow indicates site of invasion). An inset panel indicates the area where tumor cells invade into the cartilage. Tumor sections were evaluated for invasion through the basement membrane. N=6 (EV), N=6 Act (3 tumors from clone 1 and 3 tumors from clone 2). Tumors from Act mice were pooled in the graph).

E Tumor weight at endpoint (5 weeks after injection). N=3-6 tumors.

F Herovici staining and quantification of percentage of collagen-positive (dark blue) area per field of view. N=3 tumors, n=3-4 histological sections.

G Representative images of sections from tumors formed by SCC13 EV and SCC13 Act (clone 2) stained for Ki67 (red), PDGFR-α (green) and counterstained with Hoechst (blue). Quantification of Ki67/PDGFR-α positive cells is shown in the graph. N=3 tumors, n=3-4 histological sections.

H Representative images of sections from 3D cultures of primary human skin fibroblasts with either SCC13 EV or SCC13 Act (clones 1 and 2) cells stained with either H&E or Herovici.

I Quantification of Ki67-positive cells in sections from SCC13 EV and SCC13 Act (clone 2) organotypic cultures (co-stained with E-cadherin to indicate epithelial cells). N=3 independent cultures, n=3 histological sections.

J Representative images of sections from SCC13 EV and SCC13 Act (clone 2) organotypic cultures stained for K14 (red) and collagen IV (green) combined with Hoechst staining (blue) and quantification of the K14-positive area below the basement membrane (BM). N=3 independent cultures, n=4 histological sections. The area indicated with a white rectangle in the left picture is shown at higher magnification in the right picture.

Data information: Bar graphs show mean ± SEM. *p<0.05, **p<0.01, ***p<0.001, ****p<0.0001 (one-way ANOVA with Bonferroni post-test (A, J), two-way ANOVA with Bonferroni post-hoc test (C, I), unpaired Student's t-test (E (combined), F, G)), Fisher' exact test (D). Scale bars, 500 μm (D) or 100 μm (F-H, J). Exact P‐values are provided in Dataset EV3.