Fig. 4: CXCR7 stimulates Src kinase phosphorylation through β-arrestin2.

a The levels of Src phosphorylation in F10 WT cells transfected with siRNA targeting scramble control (NC), β-arrestin1 (βArr1), or β-arrestin2 (βArr2). b, e The effects of β-arrestin2 knockdown on CXCL12-induced Src phosphorylation in melanoma cells. F10 WT (b) and A375 WT (e) cells harboring scramble siRNA or β-arrestin2 siRNA were starved overnight. After pretreated with AMD3100 (1 μg/ml) for 1 h, the cells were exposed to recombinant murine (50 ng/ml) or human (100 ng/ml) CXCL12. The phosphorylation level of Src was detected by western blot. c, f The effects of β-arrestin2 downregulation on melanoma cell proliferation. Indicated cell lines were transfected with scramble siRNA or β-arrestin2 siRNA and seeded into 96-well plates. After 48 h, the cell numbers were determined by CCK-8 assays. The proliferation rates were normalized to F10 WT cells (c, top), F0 Vec cells (c bottom) or A375 WT cells (f) transfected with scramble siRNA. d, g The effects of β-arrestin2 downregulation on melanoma colony formation. Indicated cell lines were transfected with scramble siRNA or β-arrestin2 siRNA and seeded into 6-well plates. After 12 days, the colony numbers were counted. The quantitative results were normalized to F10 WT cells (d, top), F0 Vec cells (d, bottom) or A375 WT cells (g) transfected with scramble siRNA. Proliferation experiments and colony formation assays were independently repeated in triplicate. Data are presented as mean ± SD; *p < 0.05, **p < 0.01, ***p < 0.001; ns not significant