Figure 3.

Antiproliferative effects and induction of PTPN6 by 12 in TNBC cells. (A) The elevated expression of phospho-STAT3 (Y705) in TNBC cell lines. The cell lysates from exponentially growing cells were analyzed by indicated antibodies. β-Actin was used as a loading control. (B) EC₅₀ values of 12 were determined by MTT cell viability assay. Data from two independent experiments performed in triplicate are shown as mean ± SEM (C) HS578T and SUM149PT cells were treated with increasing amount of 12 for 24 h and the cell lysates were analyzed by indicated antibodies and β-actin was used as a loading control. (D) RT-PCR analysis of cells treated as in (C), GAPDH was used as a loading control. (E). The cells were treated with compound 12 or CP690550 in the absence or presence of increasing amount of pervanadate for 16 h. The cell lysates were analyzed by indicated antibodies, and β-actin was used as a loading control. (F) The cells were transfected with either control- or PTPN6-siRNA for 3 days and further treated with 12 for 24 h. The cell lysates were subjected to Western blot analysis with indicated antibodies.