Skip to main content
. Author manuscript; available in PMC: 2014 Jan 2.
Published in final edited form as: Nat Med. 2011 Mar 13;17(4):10.1038/nm.2309. doi: 10.1038/nm.2309

Figure 5.

Figure 5

Trastuzumab treatment plus SRC inhibition overcomes multiple resistance mechanisms in vitro. (a) MTS assay examining the effect of SRC inhibition in combination with trastuzumab treatment in the indicated four trastuzumab-resistant models. BT474.TtzmR cells, cells overexpressing IGF-1R and EGFR, and PTEN.shRNA cells were treated as described in Online Methods. (b) MTS assay evaluating the effects of trastuzumab, saracatinib or combination treatment in control BT474-GFP and trastuzumab-resistant cells overexpressing SRC Y527F. (c) 3D tumor spheroid assay comparing the cell proliferation of BT474. TtzmR cells upon treatment with trastuzumab alone, saracatinib alone or combination treatment. Tumor spheroid assay was carried out as described in Online Methods. Scale bar, 100 µm. (d) MTS assay comparing SRC inhibition by saracatinib and AKT inhibition by triciribine on overcoming trastuzumab resistance. (e) TUNEL assay examining induction of apoptosis by saracatinib and trastuzumab combined treatment in control (Con.shRNA) and PTEN knockdown (PTEN.shRNA) cells. TUNEL-positive cells were detected by flow cytometry. (f) The induction of DNA fragmentation (indicated by sub-G1 population detected by flow cytometry) by combined treatment with saracatinib and trastuzumab in BT474.PTEN knockdown cells (PTEN.as) and BT474.SRC constitutively active (Y527F) cells. All error bars, s.e.m. All quantitative data were generated from a minimum of three replicates.