Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, 1501 San Pablo Street, ZNI 117, Los Angeles, CA, 90033, USA.
Department of Pathology, Keck School of Medicine, University of Southern California, 2011 Zonal Ave, HMR 205, Los Angeles, CA, 9033, USA.
Sci Rep. 2021 Jul 23;11(1):15077. doi: 10.1038/s41598-021-94490-0.
Quantitative in vivo monitoring of cell biodistribution offers assessment of treatment efficacy in real-time and can provide guidance for further optimization of chimeric antigen receptor (CAR) modified cell therapy. We evaluated the utility of a non-invasive, serial Zr-oxine PET imaging to assess optimal dosing for huLym-1-A-BB3z-CAR T-cell directed to Lym-1-positive Raji lymphoma xenograft in NOD Scid-IL2Rgamma (NSG) mice. In vitro experiments showed no detrimental effects in cell health and function following Zr-oxine labeling. In vivo experiments employed simultaneous PET/MRI of Raji-bearing NSG mice on day 0 (3 h), 1, 2, and 5 after intravenous administration of low (1.87 ± 0.04 × 10 cells), middle (7.14 ± 0.45 × 10 cells), or high (16.83 ± 0.41 × 10 cells) cell dose. Biodistribution (%ID/g) in regions of interests defined over T1-weighted MRI, such as blood, bone, brain, liver, lungs, spleen, and tumor, were analyzed from PET images. Escalating doses of CAR T-cells resulted in dose-dependent %ID/g biodistributions in all regions. Middle and High dose groups showed significantly higher tumor %ID/g compared to Low dose group on day 2. Tumor-to-blood ratios showed the enhanced extravascular tumor uptake by day 2 in the Low dose group, while the Middle dose showed significant tumor accumulation starting on day 1 up to day 5. From these data obtained over time, it is apparent that intravenously administered CAR T-cells become trapped in the lung for 3-5 h and then migrate to the liver and spleen for up to 2-3 days. This surprising biodistribution data may be responsible for the inactivation of these cells before targeting solid tumors. Ex vivo biodistributions confirmed in vivo PET-derived biodistributions. According to these studies, we conclude that in vivo serial PET imaging with Zr-oxine labeled CAR T-cells provides real-time monitoring of biodistributions crucial for interpreting efficacy and guiding treatment in patient care.
定量的细胞体内分布监测可实时评估治疗效果，并可为嵌合抗原受体 (CAR) 修饰细胞治疗的进一步优化提供指导。我们评估了非侵入性、连续的 Zr-oxine PET 成像在评估针对 Lym-1 阳性 Raji 淋巴瘤异种移植物的 huLym-1-A-BB3z-CAR T 细胞的最佳剂量中的效用，这些 T 细胞在 NOD Scid-IL2Rgamma (NSG) 小鼠中。体外实验表明，Zr-oxine 标记后细胞健康和功能没有不良影响。体内实验在第 0 天（3 h）、第 1 天、第 2 天和第 5 天，对静脉注射低（1.87 ± 0.04 × 10 个细胞）、中（7.14 ± 0.45 × 10 个细胞）或高（16.83 ± 0.41 × 10 个细胞）细胞剂量的携带 Raji 肿瘤的 NSG 小鼠进行同时 PET/MRI 检测。从 PET 图像中分析了 T1 加权 MRI 定义的 ROI 中（如血液、骨骼、大脑、肝脏、肺部、脾脏和肿瘤）的生物分布（%ID/g）。随着 CAR T 细胞剂量的增加，所有区域的 %ID/g 生物分布均呈剂量依赖性。第 2 天，中剂量组和高剂量组的肿瘤 %ID/g 明显高于低剂量组。第 2 天，低剂量组的肿瘤-血液比显示出增强的血管外肿瘤摄取，而中剂量组从第 1 天开始至第 5 天显示出明显的肿瘤积累。从这些随时间获得的数据可以明显看出，静脉内给予的 CAR T 细胞在 3-5 小时内被困在肺部，然后迁移到肝脏和脾脏长达 2-3 天。这种令人惊讶的生物分布数据可能是这些细胞在靶向实体瘤之前失活的原因。离体生物分布实验证实了体内 PET 衍生的生物分布。根据这些研究，我们得出结论，Zr-oxine 标记的 CAR T 细胞的体内连续 PET 成像提供了对生物分布的实时监测，这对于解释疗效和指导患者护理中的治疗至关重要。
