Figure 3

Integrin β6 is required for sphere formation. (A) Bar plot illustrating mean sphere forming efficiency (SFE) for FACS sorted AN01 negative POP92 cells stably transduced with unique gRNAs against ITGA7 (sgITGA7s) or a control guide (sgLacZ). N = 3 biological replicates. (B) Mean SFE for FACS sorted AN02 negative POP92 cells stably transduced with shHLA-A. N = 3. (C) Mean SFE for FACS sorted AN03 negative POP92 cells stably transduced with sgITGB6. N = 4. All error bars represent SEM and significance was calculated by paired student’s t-test. (D) Pictures of POP92 cells from growth assays in the presence of 100 μg/mL AN01, AN02, or AN03 antibodies. The negative control was a non-binding IgG raised against maltose binding protein. The positive control was an anti-ROBO4 IgG previously found to block growth of POP92 cells. (E) Barplots showing the results of POP92 sphere forming assays in the presence of the indicated antibodies. Controls were the same as described in part D. PBS = phosphate buffered saline. Error bars represent standard deviation (n = 3) and ‘ns’ is not significant. (F) POP92 xenograft tumour sections stained by immunohistochemistry (IHC) with MATF1037 (anti-ITGB6 antibody), phospho-SMAD3 S424 + S425 antibody or AN03. Scale bar is 50 uM. *p < 0.05, **p < 0.01, ***p < 0.001.