Division of RI Application, Korea Institute of Radiological and Medical Sciences (KIRAMS), 75 Nowon-ro, Nowon-gu, Seoul 01812, Korea.
Radiological and Medico-Oncological Sciences, University of Science and Technology (UST), 75 Nowon-ro, Nowon-gu, Seoul 01812, Korea.
Int J Mol Sci. 2019 Sep 23;20(19):4708. doi: 10.3390/ijms20194708.
For optimum radioimmunotherapy (RIT), deep penetration and uniform distribution into the tumor core is important. The solid tumor microenvironment, consisting of a highly fibrotic or desmoplastic tumor, abnormal tumor vasculature, high fluid pressure, and the absence of fluid lymphatics, limits the distribution of monoclonal antibodies mAbs to the tumor core. To investigate the optimal rationale for therapeutic mAbs administration and the microdistribution of mAbs, single and serial fractional dosage regimens of Cu-64-trastuzumab (TRZ) with paclitaxel were evaluated. Groups of nude mice were inoculated with gastric cancer cell line NCI-N87 tumor cells. When the tumor size reached 200 ± 20 mm, the mice were divided into two groups for injection of Alexa-647-TRZ. One group ( = 5) was injected with 15 mg/kg in a single dose (SD), and the other group ( = 5) with two doses of 7.5 mg/kg (fractionated dose (FD)). In both cases, the injections were done intravenously in combination with intraperitoneal paclitaxel either as a SD of 70 mg/kg or fractionated into two doses of 40 and 30 mg/kg. Tumors were harvested, flash frozen, and sectioned (8 µm) five days after Alexa-647-TRZ injection. Rhodamine lectin (rhodamine-labeled agglutinin I, 1 mg in 0.2 mL of phosphate-buffered saline (PBS)) was intravenously injected to delineate the functional vessel for a wait time of 5 min before animal euthanization. Microscopic images were acquired with an IN Cell Analyzer. The amount of TRZ that penetrated the tumor surface and the tumor vessel was calculated by area under the curve (AUC) analysis. For RIT efficacy ( = 21), Cu-64-TRZ was injected following the same dose schedule to observe tumor volume and survival ratio for 30 days. The SD and FD regimens of Alexa-647-TRZ were observed to have no significant difference in penetration of mAbs from the tumor edge and vessel, nor was the total accumulation across the whole tumor tissue significantly different. Additionally, the SD and FD regimens of Cu-64-TRZ were not proven to be significantly efficacious. Our study reveals that SD and FD in a treatment design with Cu-64-TRZ and paclitaxel shows no significant difference in therapeutic efficacy on tumor growth inhibition in vivo in mice bearing human gastric cancer xenografts overexpressing HER2 antigen.
为了实现最佳的放射免疫治疗（RIT），深入肿瘤核心并实现均匀分布非常重要。由高度纤维化或促结缔组织形成的肿瘤、异常的肿瘤血管、高流体压力和缺乏流体淋巴管组成的实体肿瘤微环境限制了单克隆抗体（mAb）在肿瘤核心的分布。为了研究治疗性 mAb 给药的最佳原理和 mAb 的微观分布，评估了 Cu-64-曲妥珠单抗（TRZ）与紫杉醇的单次和连续分次剂量方案。将裸鼠分组接种胃癌细胞系 NCI-N87 肿瘤细胞。当肿瘤大小达到 200±20mm 时，将小鼠分为两组，静脉注射 Alexa-647-TRZ。一组（n=5）注射 15mg/kg 单次剂量（SD），另一组（n=5）注射 7.5mg/kg 分次剂量（FD）。在这两种情况下，均静脉注射紫杉醇，SD 为 70mg/kg，或分为两次 40mg/kg 和 30mg/kg。在 Alexa-647-TRZ 注射后 5 天收获、快速冷冻和切片（8μm）。注射罗丹明凝集素（罗丹明标记的凝集素 I，0.2mL 磷酸盐缓冲液（PBS）中 1mg）以描绘功能血管，等待 5min 后处死动物。使用 IN Cell Analyzer 获取显微镜图像。通过曲线下面积（AUC）分析计算穿透肿瘤表面和肿瘤血管的 TRZ 量。对于 RIT 效果（n=21），在相同剂量方案下注射 Cu-64-TRZ，观察 30 天肿瘤体积和存活率。观察到 Alexa-647-TRZ 的 SD 和 FD 方案在 mAb 从肿瘤边缘和血管中的穿透方面没有显著差异，整个肿瘤组织的总累积量也没有显著差异。此外，Cu-64-TRZ 的 SD 和 FD 方案并未证明在体内抑制人胃癌过表达 HER2 抗原异种移植瘤的生长方面具有显著疗效。
我们的研究表明，在 Cu-64-TRZ 和紫杉醇的治疗设计中，单次和分次给药方案在抑制体内肿瘤生长方面没有显著差异，在过表达 HER2 抗原的人胃癌异种移植瘤小鼠中。
