An antibody-drug conjugate (ADC) is a promising therapeutic modality because selective and effective delivery of an anti-cancer drug is achieved by drug-conjugated antibody-targeting cancer antigen. Glypican 1 (GPC1) is highly expressed in malignant tumors, including pancreatic ductal adenocarcinoma (PDAC) and esophageal squamous cell carcinoma (ESCC). Herein, we describe the usefulness of GPC1-targeting ADC. Humanized anti-GPC1 antibody (clone T2) was developed and conjugated with monomethyl auristatin E (MMAE) via maleimidocaproyl-valine-citrulline-p-aminobenzyloxycarbonyl (mc-vc-PABC) linkers (humanized GPC1-ADC[MMAE]). Humanized GPC1-ADC(MMAE) inhibited the growth of GPC1-positive PDAC and ESCC cell lines via inducing cycle arrest in the G2/M phase and apoptosis in vitro. The binding activity of humanized GPC1-ADC(MMAE) with GPC1 was comparable with that of the unconjugated anti-GPC1 antibody. The humanized GPC1-ADC(MMAE) was effective in GPC1-positive BxPC-3 subcutaneously xenografted mice but not in GPC1-negative BxPC-3-GPC1-KO xenografted mice. To assess the bystander killing activity of the humanized GPC1-ADC(MMAE), a mixture of GPC1-positive BxPC-3 and GPC1-negative BxPC-3-GPC1-KO-Luc cells were subcutaneously inoculated, and a heterogenous GPC1-expressing tumor model was developed. The humanized GPC1-ADC(MMAE) inhibited the tumor growth and decreased the luciferase signal, measured with an in vivo imaging system (IVIS), which suggests that the suppression of the BxPC-3-GPC1-KO-Luc population. The humanized GPC1-ADC(MMAE) also inhibited the established liver metastases of BxPC-3 cells and significantly improved the overall survival of the mice. It exhibited a potent antitumor effect on the GPC1-positive PDAC and ESCC patient-derived xenograft (PDX) models. Our preclinical data demonstrate that GPC1 is a promising therapeutic target for ADC.

抗体-药物偶联物 (ADC) 是一种很有前景的治疗方式，因为抗癌药物的选择性和有效递送是通过药物偶联抗体靶向癌症抗原来实现的。Glypican 1 (GPC1) 在恶性肿瘤中高度表达，包括胰腺导管腺癌 (PDAC) 和食管鳞状细胞癌 (ESCC)。在这里，我们描述了针对 GPC1 的 ADC 的有用性。开发了人源化抗 GPC1 抗体（克隆 T2），并通过马来酰亚胺己酰-缬氨酸-瓜氨酸-p-氨基苄氧羰基 (mc-vc-PABC) 接头与单甲基 auristatin E (MMAE) 偶联（人源化 GPC1-ADC[MMAE]）。人源化 GPC1-ADC(MMAE) 通过诱导 G2/M 期周期阻滞和体外凋亡抑制 GPC1 阳性 PDAC 和 ESCC 细胞系的生长。人源化 GPC1-ADC(MMAE) 与 GPC1 的结合活性与未偶联的抗 GPC1 抗体相当。人源化 GPC1-ADC(MMAE) 对 GPC1 阳性 BxPC-3 皮下异种移植小鼠有效，但对 GPC1 阴性 BxPC-3-GPC1-KO 异种移植小鼠无效。为了评估人源化 GPC1-ADC (MMAE) 的旁观者杀伤活性，皮下接种 GPC1 阳性 BxPC-3 和 GPC1 阴性 BxPC-3-GPC1-KO-Luc 细胞的混合物，以及表达 GPC1 的异源性肿瘤模型被开发出来。人源化 GPC1-ADC(MMAE) 抑制肿瘤生长并降低荧光素酶信号，用体内成像系统 (IVIS) 测量，这表明 BxPC-3-GPC1-KO-Luc 群受到抑制。人源化 GPC1-ADC(MMAE) 还抑制了 BxPC-3 细胞已建立的肝转移，并显着提高了小鼠的总体存活率。它对 GPC1 阳性 PDAC 和 ESCC 患者来源的异种移植 (PDX) 模型表现出有效的抗肿瘤作用。我们的临床前数据表明，GPC1 是 ADC 的一个有希望的治疗靶点。