Therapeutic Potential of Amanitin-Conjugated Anti-Epithelial Cell Adhesion Molecule Monoclonal Antibody Against Pancreatic Carcinoma
Therapeutic Potential of Amanitin-Conjugated Anti-Epithelial Cell Adhesion Molecule Monoclonal Antibody Against Pancreatic Carcinoma
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DOI：
10.1093/jnci/djs140
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发表时间：
2012-04-01
影响因子：
10.3
通讯作者：
Faulstich, Heinz
中科院分区：
文献类型：
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作者：
Moldenhauer, Gerhard;Salnikov, Alexei V.;Faulstich, Heinz
背景人上皮细胞粘附分子（EpCAM）在许多癌症中过表达。抗EpCAM抗体在临床前研究中显示出前景，但在最近的II期临床试验中没有显示肿瘤消退。因此，我们产生了一种新的抗EpCAM抗体-药物缀合物，并评估它是否表现出增强的抗肿瘤effects.Methods化学交联进行共价结合α-鹅膏蕈碱，已知抑制DNA转录的毒素，与嵌合抗EpCAM单克隆抗体chiHEA 125，产生抗体-药物缀合物α-鹅膏蕈碱-戊二酸-chiHEA 125（chiHEA 125-Ama）。使用[H-3]-胸苷掺入测定法在体外在人胰腺癌（BxPc-3和Capan-1）、结肠直肠癌（Colo 205）、乳腺癌（MCF-7）和胆管癌（OZ）细胞系中测试chiHEA 125-Ama的抗增殖活性。在携带皮下人BxPc-3胰腺癌异种移植肿瘤的免疫受损小鼠（n = 66只小鼠）中体内评估chiHEA 125-Ama的抗肿瘤活性。通过免疫组织化学方法评价异种移植瘤中细胞增殖和凋亡。结果在所有细胞系中，chiHEA 125-Ama均能抑制细胞增殖（平均半数最大抑制浓度[IC 50] = 2.5 × 10 - 10 ~ 5.4 × 10 - 12 M）。单剂量的chiHEA 125-Ama抑制BxPc-3异种移植肿瘤生长（chiHEA 125 [对照，n = 4只小鼠]对chiHEA 125-Ama [n = 6只小鼠]，对于IgG的剂量为15 mg/kg，对于α-鹅膏蕈碱的剂量为50 μ g/kg，第16天肿瘤体积的平均相对增加= 884%对-79%，差异= 963%，95% CI = 582%至1344%，P = .019）。两个较高剂量的chiHEA 125-Ama（100 μ g/kg，相对于α-鹅膏蕈碱），间隔1周给药（每组n = 10只小鼠），在16天的观察期内，与chiHEA 125相比，导致10只小鼠中的9只（90%）的肿瘤完全消退;在用chiHEA 125-Ama处理的小鼠中观察到细胞凋亡增加和细胞增殖减少。鹅膏蕈碱具有成为胰腺癌和各种表达EpCAM的恶性肿瘤的高效治疗剂的潜力。J Natl Cancer Inst 2012;104：622-634
Background Human epithelial cell adhesion molecule (EpCAM) is overexpressed in many cancers. Anti-EpCAM antibodies have shown promise in preclinical studies, but showed no tumor regression in a recent phase II clinical trial. Therefore, we generated a novel anti-EpCAM antibody-drug conjugate and assessed whether it showed enhanced antitumor effects.Methods Chemical cross-linking was conducted to covalently conjugate alpha-amanitin, a toxin known to inhibit DNA transcription, with chiHEA125, a chimerized anti-EpCAM monoclonal antibody, to generate the antibody-drug conjugate alpha-amanitin-glutarate-chiHEA125 (chiHEA125-Ama). Antiproliferative activity of chiHEA125-Ama was tested in human pancreatic (BxPc-3 and Capan-1), colorectal (Colo205), breast (MCF-7), and bile duct (OZ) cancer cell lines in vitro using [H-3]-thymidine incorporation assay. Antitumor activity of chiHEA125-Ama was assessed in vivo in immunocompromised mice bearing subcutaneous human BxPc-3 pancreatic carcinoma xenograft tumors (n = 66 mice). Cell proliferation and apoptosis were evaluated in xenograft tumors by immunohistochemistry. All statistical tests were two-sided.Results In all cell lines, chiHEA125-Ama reduced cell proliferation (mean half maximal inhibitory concentration [IC50] = 2.5 x 10(-10) to 5.4 x 10(-12) M). A single dose of chiHEA125-Ama inhibited BxPc-3 xenograft tumor growth (chiHEA125 [control, n = 4 mice] vs chiHEA125-Ama [n = 6 mice], dose of 15 mg/kg with respect to IgG and 50 mu g/kg with respect to a-amanitin, mean relative increase in tumor volume on day 16 = 884% vs -79%, difference = 963%, 95% CI = 582% to 1344%, P = .019). Two higher doses of chiHEA125-Ama (100 mu g/kg with respect to alpha-amanitin), administered 1 week apart (n = 10 mice per group), led to complete tumor regression in nine of 10 (90%) mice compared with chiHEA125, during the observation period of 16 days; increased apoptosis and reduced cell proliferation were observed in mice treated with chiHEA125-Ama.Conclusion This preclinical study suggests that anti-EpCAM antibody conjugates with alpha-amanitin have the potential to be highly effective therapeutic agents for pancreatic carcinomas and various EpCAM-expressing malignancies. J Natl Cancer Inst 2012;104:622-634