Knockdown and overexpression of AHI-1 in CTCL cells mediate their GF-independent colony-forming ability and their response to Src tyrosine kinase inhibitor, DS. (A) Western analysis of AHI-1 protein expression in control Hut 78 cells, AHI-1–suppressed cells (sh4 bulk), and AHI-1–overexpressed cells (Hut 78 AHI-1). The bottom panel shows quantification of AHI-1 protein expression relative to actin. (B) The number of GF-independent CFC colonies produced and their appearance in semisolid cultures in the same transduced cells. (C,D) CFCs produced in semisolid cultures in response to DS and IM. Values shown are the mean ± SEM. The P values presented are the result of 2-sample t tests comparing the results in cells with AHI-1 suppression and overexpression with that of Hut 78 controls.