Additional file 7: of Posttranscriptional upregulation of HER3 by HER2 mRNA induces trastuzumab resistance in breast cancer

Figure S3. Combinatory treatment with HER3 siRNA and trastuzumab is useful for overcoming trastuzumab resistance. (A-C) Real-time PCR (A), western blotting (B), and FACS (C) analysis of HER2 and HER3 expression in AU565 parental and trastuzumab-resistant (TtzmR) cell lines. (D) Proliferation of AU565 parental and TtzmR cells treated with 10 μg/ml trastuzumab or control IgG, along with a cholesterol-conjugated siRNA targeting HER3 or a randomized oligonucleotide (control). All error bars represent the standard deviation. All quantitative data were generated from a minimum of three replicates. (E, F) AU565 TtzmR cells were s.c. injected into female BALB/c-nude mice. Mice were treated with cholesterol-conjugated HER3 siRNA or trastuzumab at days 0, 7, and 14. Representative in vivo luciferase images of mice at days 0, 10, and 21(E). The results are presented as means ± SD from five mice. Immunostaining of HER3 in xenograft tumor sections (F). Red, HER3; Blue, DAPI. Scale bar, 40 μm. (PDF 3149 kb