Wang Yang, He Shuhua, Ma Lin, Kuang Zijun, Mu Chao, Yang Jian, Liu Yuxia, Li Zheng, Li Qingnuan
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Mol Pharm. 2025 May 5;22(5):2535-2544. doi: 10.1021/acs.molpharmaceut.4c01427. Epub 2025 Apr 8.
Radiopharmaceuticals are a promising therapeutic strategy for tumors with less reduced resistance and minimal side effects. In our previous study, we radiolabeled the monoclonal antibody zolbetuximab, which targets CLDN18.2, with I, and the labeled compound showed favorable tumor targeting and retention. In this research article, [I]I-zolbetuximab was prepared to investigate its therapeutic effect on gastric cancer using and studies. The zolbetuximab was radiolabeled with I using the Iodogen method. The uptake mechanism of [I]I-zolbetuximab was investigated through an endocytosis experiment using MKN45-CLDN18.2 and MKN45 cells. The safety assessment of [I]I-zolbetuximab was conducted in normal mice using hematoxylin/eosin (H&E) staining. The tumor uptake, biodistribution, and therapeutic efficacy of [I]I-zolbetuximab were evaluated in nude mice bearing MKN45-CLDN18.2 tumors, while the hematological analysis, immunohistochemistry, Western blotting (WB), immunofluorescence, and H&E assays were used to further assess the treatment response and toxicity. [I]I-Zolbetuximab exhibited a high labeling efficiency of (96.05 ± 0.23)%, a specific activity of 1.75 × 10 GBq/μmol, and good stability. The binding of [I]I-zolbetuximab to the membrane surface receptors of MKN45-CLDN18.2 cells resulted in significant tumor uptake, retention, and favorable biodistribution in CLDN18.2-positive tumor-bearing nude mice. Safety assessments, including H&E staining, indicated no significant damage to normal mouse organs caused by the labeled compounds. In a therapeutic study involving MKN45-CLDN18.2 tumor-bearing nude mice, increasing drug dose led to notable enhancements in therapeutic efficacy and survival rates. H&E staining of mouse organs at the end of treatment showed no significant toxicity was observed across all dose groups throughout the treatment period. Furthermore, immunohistochemistry, immunoblotting, and immunofluorescence analyses conducted on mouse tumors at the treatment end point demonstrated a reduction in CLDN18.2 expression following treatment. Altogether, [I]I-zolbetuximab displayed exceptional targeting capability, tumor retention property, significant therapeutic efficacy, and safety. These findings suggest its potential to serve as a targeted radiopharmaceutical for the treatment of CLDN18.2-positive gastric cancer.
放射性药物是一种很有前景的肿瘤治疗策略，具有较低的耐药性和最小的副作用。在我们之前的研究中，我们用碘-131对靶向紧密连接蛋白18.2（CLDN18.2）的单克隆抗体zolbetuximab进行了放射性标记，标记后的化合物显示出良好的肿瘤靶向性和滞留性。在这篇研究文章中，制备了碘-131标记的zolbetuximab（[I]I-zolbetuximab），通过体内和体外研究来考察其对胃癌的治疗效果。采用Iodogen法用碘-131对zolbetuximab进行放射性标记。通过使用MKN45-CLDN18.2细胞和MKN45细胞的内吞实验研究了[I]I-zolbetuximab的摄取机制。使用苏木精/伊红（H&E）染色在正常小鼠中对[I]I-zolbetuximab进行安全性评估。在荷MKN45-CLDN18.2肿瘤的裸鼠中评估了[I]I-zolbetuximab的肿瘤摄取、生物分布和治疗效果，同时使用血液学分析、免疫组织化学、蛋白质免疫印迹（WB）、免疫荧光和H&E检测进一步评估治疗反应和毒性。[I]I-zolbetuximab表现出较高的标记效率（96.05±0.23）%、比活度为1.75×10 GBq/μmol以及良好的稳定性。[I]I-zolbetuximab与MKN45-CLDN18.2细胞膜表面受体的结合导致在CLDN18.2阳性荷瘤裸鼠中有显著的肿瘤摄取、滞留和良好的生物分布。包括H&E染色在内的安全性评估表明标记化合物对正常小鼠器官没有造成明显损伤。在一项涉及荷MKN45-CLDN18.2肿瘤裸鼠的治疗研究中，增加药物剂量导致治疗效果和生存率显著提高。治疗结束时对小鼠器官进行H&E染色显示在整个治疗期间所有剂量组均未观察到明显毒性。此外，在治疗终点对小鼠肿瘤进行免疫组织化学、免疫印迹和免疫荧光分析表明治疗后CLDN18.2表达降低。总之，[I]I-zolbetuximab表现出卓越的靶向能力、肿瘤滞留特性、显著的治疗效果和安全性。这些发现表明它有潜力作为一种靶向放射性药物用于治疗CLDN18.2阳性胃癌。
