Figure 4. Lkb1 Loss Results in SFK Activation.

(A) Representative western analysis of TKp53^L/L; p16^L/L cells with or without Lkb1 knockdown is shown. Cell lysates were either directly immunoblotted (IB) with antibody against p-SFKs (Y416) or immunoprecipitated (IP) first with indicated antibodies against Src, Fyn, or Yes. NS, nonspecific shRNA.

(B) TKp53^L/L; p16^L/L melanoma cells with or without LKB1 knockdown were grown in media containing vehicle (DMSO) or dasatinib (30 nM). Closure index was measured 12 hr after wounding.

(C) TKp53^L/L; p16^L/L melanoma cells with or without LKB1 knockdown were subjected to Matrigel invasion assay with and without treatment with pan-SFK inhibitor, dasatinib (30 nM).

(D) Representative western analysis of indicated human melanoma cells with LKB1 quantification by LICOR analysis is shown.

(E) YES phosphorylation in indicated human melanoma cells with phospho-YES level quantification by LICOR analysis is presented. Cells were labeled with the same number as in (D).

(F) Correlation analysis of LKB1 and phospho-YES expression in human melanoma cells is illustrated. Cells were labeled with the same number as in (D).

(G and H) SKMel23, SKMel63, and A2058 cells were treated with DMSO or 30 nM dasatinib and subjected to in vitro scratch assay (G) or Matrigel invasion assay (H).

Error bars show SD. *p < 0.05; **p < 0.01; ***p < 0.001.

See also Figure S4.