In Vivo Experiment Of Trastuzumab Combined With Recombinant Human Eddostation In HER2-overexpressing Breast Carcinoma

Objective:In this study, we aimed to investigate the combined effect of Trastuzumab plus recombinant human Endostatin on SK-BR3breast carcinoma cells in vivo, and its underlying mechanism.Methods:BALB/c nude mouse model bearing SK-BR3mammary carcinoma was established and randomizly divided into4groups (every group of8mice) when the tumors grew to100-150mm3:A, control group (untreated); B, recombinant human Endostatin (rh-Endostatin) group; C, Trastuzumab group; D, combined treatment group. The tumor sizes were measured using a caliper. Tumor volume was calculated using the formula:(lengthxwidth2)/2before treatment and every3days after treatment. On day21after treatment,8mice of each group were sacrificed with their tumors removed and weighed to botain tumor weight. The rate of tumor growth is determined by tumor growth curve. Flow cytometry was performed to analyze the apoptosis of breast cancer cells. Immunohistochemical staining methods were used to measure the relative protein level of Ki67, CD34and VEGF. Western-blot was designed to determine the protein expression of phosphorylated Akt (p-Akt) and Dynamin-related protein1(Drpl).Results:1. The tumor growth inhibition of combined therapeutic regimen on SK-Br3xenograft BALB/c nude mouse model:All treatment groups showed tumor-inhibiting effects. There was no obvious difference between two single treatment groups (P>0.05). The combination group showed significantly higher inhibition rate than the single treatment group (P<0.05), while no obvious difference between two single treatment groups (P>0.05).2. The tumor gowth inhibition (TGI) of combined therapeutic regimen on SK-Br3xenograft BALB/c nude mouse model. TGI in the combined treatment group was higher than the single treatment group, and had statistic significance with the single treatment group(P<0.05). There was no statistic significance between two single treatment groups(P>0.05). 3. Combined therapeutic regimen lowers Ki-67expression in SK-Br3xenograft tumors:Combined with the control group, Ki-67protein level in the two single treatment group and combination treatment group decreased obviously (P<0.05), especially the combination group (P<0.05). However, There was no statistic significance between two single groups (P>0.05).4. Combined therapeutic regimen reduces tumor MVD:Combined with the control group, MVD in the two single treatment group and combination treatment group decreased obviously (P<0.05), especially the combination group(P<0.05). However, There was no statistic significance between two single groups (P>0,05).5. Combined therapeutic regimen inhibits tumor vessel VEGF expression. Compared with the control group, VEGF protein level in the two single treatment group and combination treatment group decreased obviously, especially the combination group (P<0.05). However, There was no statistic significance between two single treatment groups(P>0.05).6. Combined therapeutic regimen can significantly inhibit the protein expression of phosphorylated Akt (p-Akt) and up-regulate Dynamin-related protein1(Drpl).Conclusions:Our results indicated that Trastuzumab plus recombinant human Endostatin treatment efficiently repressed the tumor growth and angiogeneis of HER2overexpression breast cancer cell in xenograft BALB/c nude mouse model, and provided theoretical basis for clinical application.