Figure 6. ADAM10 and ADAM17 regulate cell surface AXL and alter cell growth in an AXL-dependent manner.
A–B) ADAM-targeted siRNAs (validation: Fig. S6A) reduce supernatant AXL (A; ELISA measurement) and increase surface AXL (B; live-cell immunostaining) compared to non-targeted siRNA (*p<0.05; n≥2) in MDA-MB231. C) The specific ADAM10 inhibitor GI-254023X decreases supernatant AXL from MDA-MB231 (*p<0.05; n=3). D) The specific ADAM10 inhibitor proA10 reduces supernatant AXL compared to the vehicle control, measured by ELISA using MDA-MB231 (*p<0.05; n≥2). E–F) Recombinant ADAM10 cleaves recombinant AXL in a dose-response fashion, shown by AXL immunoblot (E) and corresponding quantification (F; *p<0.05; two-tailed t-test; n=2). G) Recombinant ADAM10 and ADAM17 cleave recombinant AXL, and cleavage is blocked by MPi using BB94 (n=2). H) In MDA-MB231 cells, ADAM10 inhibition or knockdown by siRNA only decreases proliferation in the presence of AXLi using R428. ADAM17 siRNA only induces proliferation in the absence of AXLi. SiRNA results were measured 24h after AXLi, 72h after transfection, and GI-254023X results were measured after 72h treatment (*p<0.05; n≥4; two-tailed t-test).