Fig. 7: Trastuzumab–TFBG combination is efficient in treatment of HER2-positive gastric cancer.

a, b Sensitivity to trastuzumab (Trast) in SNU-216 (a) and NCI-N87 (b) cells treated with theaflavine-3, 3′-digallate (TFBG) at the indicated concentrations. Cell proliferation was analyzed after 6 days of treatment. Data are the mean ± s.e.m. The p values were determined by one-way ANOVA (n = 6 independent biological samples). c, d Colony formation (c) and the statistical results (d) of NCI-N87 and SNU-216 cells in the continuous presence of trastuzumab (10 μg/mL) and/or TFBG (10 μM). Data are the mean ± s.e.m. The p values were determined by one-way ANOVA (n = 3 independent biological samples). e Representative image and tumor growth curves of xenograft mice carrying NCI-N87 cell tumors treated with trastuzumab (intraperitoneal, 10 mg/kg, 2×/wk × 3), TFBG (intraperitoneal, 50 mg/kg, 1×/day × 21), or a combination of the agents. The detailed strategy of drugs treatment is displayed (e, top). Data are the mean ± s.e.m. The p values were determined by one-way ANOVA (n = 8 independent mice per group). f Representative images of hematoxylin–eosin (H&E) and Ki-67 immunohistochemical analysis (top) and quantification of Ki-67-positive cells (bottom) in mice xenograft tumors treated with trastuzumab and/or TFBG. Data are the mean ± s.e.m. The p values were determined by one-way ANOVA (n = 6 independent biological samples). g, h Immunofluorescence staining and the statistical results of SHCBP1 nuclear localization in mice xenograft tumors. Tissues were co-stained with anti-SHCBP1 antibody (green), anti-ERBB2 antibody (red), and DAPI (blue). The positivity of SHCBP1 in the nucleus was quantified using Image J V1.53c software. Data are the mean ± s.e.m. The p values were determined by one-way ANOVA (n = 6 independent biological samples). i Detection of MISP phosphorylation in mice xenograft tumors by immunoblotting. Data of i are representative of two independent experiments.