Background

Positron emission tomography (PET) imaging is a non-invasive method to visualize and quantify the tumor microenvironment. This study aimed to explore the feasibility of ¹⁸F-AIF-NOTA-E[PEG₄-c(RGDfk)]₂ (denoted as ¹⁸F-RGD) PET quantitative parameters to distinguish the angiogenesis in colorectal cancer (CRC) mice which has different metastatic potential.

Methods

Twenty LoVo and twenty LS174T of CRC liver metastases animal models were established by implantation of human CRC cell lines via intrasplenic injection. Radiotracer-based micro-PET imaging of animal model was performed and the uptake of ¹⁸F-RGD tracer in the tumor tissues was quantified as tumor-to-liver maximum or mean standardized uptake value (SUVmax or SUVmean) ratio. Pearson correlation was used to analyze the relationship between radioactive parameters and tumor markers.

Results

The SUVmax and SUVmean ratios of LoVo model were significantly higher than those of LS174T in both liver metastasis and primary tumor lesions (P < 0.05). A significant difference was observed in both vascular endothelial growth factor (VEGF) and Ki67 expressions between LoVo and LS174T primary tumors (P < 0.05). The tumor-to-liver SUVmax or SUVmean ratio of ¹⁸F-RGD showed a moderate correlation with VEGF expression (r = 0.5700, P = 0.001 and r = 0.6657, P < 0.001, respectively), but the SUVmean ration showed a weak correlation with Ki67 expression (r = 0.3706, P < 0.05). The areas under the receiver operating characteristic (ROC) curves of ¹⁸F-RGD SUVmean ratio, SUVmax ratio for differentiating LoVo from LS174T tumor were 0.801 and 0.759, respectively.

Conclusions

The tumor-to-liver SUVmean ratio of ¹⁸F-RGD was a promising image parameter for the process of monitoring tumor angiogenesis in CRC xenograft mice model.

中文翻译：

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基于18F-RGD的显微正电子发射断层成像血管生成评估结直肠癌肝转移

背景

正电子发射断层扫描 (PET) 成像是一种可视化和量化肿瘤微环境的非侵入性方法。本研究旨在探讨¹⁸ F-AIF-NOTA-E[PEG ₄ -c(RGDfk)] ₂ (记为¹⁸ F-RGD) PET 定量参数区分结直肠癌 (CRC) 小鼠血管生成的可行性。不同的转移潜能。

方法

20个LoVo和20个LS174T的CRC肝转移动物模型通过脾内注射植入人CRC细胞系建立。对动物模型进行基于放射性示踪剂的微 PET 成像，并将¹⁸ F-RGD 示踪剂在肿瘤组织中的摄取量化为肿瘤与肝脏的最大值或平均标准化摄取值（SUVmax 或 SUVmean）比率。Pearson相关性用于分析放射性参数与肿瘤标志物之间的关系。

结果

LoVo模型的SUVmax和SUVmean比值在肝转移灶和原发灶中均显着高于LS174T（P <0.05）。LoVo和LS174T原发性肿瘤的血管内皮生长因子（VEGF）和Ki67表达均存在显着差异（P < 0.05）。¹⁸ F-RGD的肿瘤与肝脏 SUVmax 或 SUVmean 比值与 VEGF 表达呈中度相关性（分别为r  = 0.5700，P  = 0.001 和r  = 0.6657，P < 0.001），但 SUVmean 比值显示出弱相关性Ki67 表达式 ( r  = 0.3706, P< 0.05)。¹⁸ F-RGD SUVmean比值、SUVmax比值区分LoVo与LS174T肿瘤的受试者工作特征（ROC）曲线下面积分别为0.801和0.759。

结论

¹⁸ F-RGD的肿瘤与肝脏 SUVmean 比值是用于监测 CRC 异种移植小鼠模型中肿瘤血管生成过程的有前景的图像参数。