Product Research Department, API Process Development Department, and Discovery Platform Technology Department, Chugai Pharmaceutical Co., Kanagawa, Japan.
Clin Cancer Res. 2011 Aug 1;17(15):5060-70. doi: 10.1158/1078-0432.CCR-10-2927. Epub 2011 Jun 23.
We investigated the antitumor activity of the combination of two different humanized monoclonal human epidermal growth factor receptor (HER) 2 antibodies, pertuzumab and trastuzumab, for gastric cancer.
Tumor mouse xenograft models were used to examine antitumor activity. Cell proliferation was examined using crystal violet staining. HER family proteins' expression was analyzed by ELISA and immunohistochemistry. Phosphorylated proteins and heterodimers were detected by Western blotting and in situ proximity ligation assay (PLA), respectively. Apoptosis activity was examined by caspase 3/7 activity. Antibody-dependent cellular cytotoxicity (ADCC) activity was detected by xCELLigence. Microvessel density was examined by CD31 staining.
Pertuzumab in combination with trastuzumab showed significant antitumor activity compared with each monotherapy in NCI-N87, an HER2-positive human gastric cancer xenograft model. The efficacy was stronger than that of the maximum effective dose with each monotherapy. Similar antitumor activity was shown in 4-1ST, another HER2-positive gastric cancer model, but not in MKN-28, an HER2-negative model. Combining pertuzumab with trastuzumab enhanced cell growth inhibition and apoptosis activity by inhibiting EGFR-HER2 heterodimerization and the phosphorylation of these receptors and their downstream factors. This effect was also seen in HER2-HER3 signaling. Furthermore, pertuzumab in combination with trastuzumab potentiated the ADCC activity of those antibodies and reduced tumor microvessel density.
We showed the significantly enhanced efficacy of pertuzumab combining with trastuzumab for HER2 overexpressing gastric cancer through the potentiation of cell growth inhibition, apoptosis activity, cell killing activity by ADCC, and antiangiogenic activity. This study suggests the clinical benefit of combination therapy with pertuzumab and trastuzumab for patients with HER2-positive gastric cancers.
我们研究了两种不同的人源化单克隆人表皮生长因子受体（HER）2 抗体曲妥珠单抗和帕妥珠单抗联合用于胃癌的抗肿瘤活性。
使用肿瘤小鼠异种移植模型来检测抗肿瘤活性。使用结晶紫染色法检测细胞增殖。通过 ELISA 和免疫组织化学分析检测 HER 家族蛋白的表达。通过 Western blot 和原位邻近连接分析（PLA）分别检测磷酸化蛋白和异源二聚体。通过 caspase 3/7 活性检测凋亡活性。通过 xCELLigence 检测抗体依赖性细胞毒性（ADCC）活性。通过 CD31 染色检测微血管密度。
与每种单药治疗相比，帕妥珠单抗联合曲妥珠单抗在 NCI-N87（一种 HER2 阳性人胃癌异种移植模型）中显示出显著的抗肿瘤活性。疗效强于每种单药的最大有效剂量。在另一种 HER2 阳性胃癌模型 4-1ST 中也显示出相似的抗肿瘤活性，但在 HER2 阴性模型 MKN-28 中则没有。帕妥珠单抗联合曲妥珠单抗通过抑制 EGFR-HER2 异源二聚体形成和这些受体及其下游因子的磷酸化，增强细胞生长抑制和凋亡活性。这种作用也见于 HER2-HER3 信号通路。此外，帕妥珠单抗联合曲妥珠单抗增强了这些抗体的 ADCC 活性，并降低了肿瘤微血管密度。
我们通过增强细胞生长抑制、凋亡活性、ADCC 细胞杀伤活性和抗血管生成活性，显示了帕妥珠单抗联合曲妥珠单抗治疗 HER2 过表达胃癌的显著疗效。这项研究表明，对于 HER2 阳性胃癌患者，联合使用帕妥珠单抗和曲妥珠单抗具有临床获益。
