Tissue factor (TF), a blood coagulation protein, plays an important role in tumor growth, invasion, and metastasis. Ixolaris, a tick-derived non-immunogenic molecule that binds to TF, has demonstrated in vivo inhibitory effect on murine models of melanoma, including primary growth and metastasis. This work aimed to: I) develop an efficient and stable labeling technique of ixolaris with Iodine-131(131I); II) compare the biodistribution of 131I and 131I-ixolaris in tumor-free and melanoma-bearing mice; III) evaluate whether 131I-ixolaris could serve as an antimetastatic agent. Ixolaris radioiodination was performed using iodogen, followed by liquid paper chromatography. Labeling stability and anticoagulant activity were measured. Imaging studies were performed after intravenous administration of free 131I or 131I-ixolaris in a murine melanoma model employing the B16-F10 cell line. Animals were divided in three experimental groups: the first experimental group, D0, received a single-dose of 9.25 MBq of 131I-ixolaris at the same day the animals were inoculated with melanoma cells. In the second group, D15, a single-dose of 9.25 MBq of 131I-ixolaris or free 131I was applied into mice on the fifteenth day after the tumor induction. The third group, D1-D15, received two therapeutic doses of 9.25 MBq of 131I-ixolaris or 131I. In vitro studies demonstrated that 131I-ixolaris is stable for up to 24 h and retains its inhibitory activity on blood coagulation. Biodistribution analysis and metastasis assays showed that all treatment regimens with 131I-ixolaris were effective, being the double-treatment (D1/D15) the most effective one. Remarkably, treatment with free 131I showed no anti-metastatic effect. 131I-ixolaris is a promising theranostic agent for metastatic melanoma.

中文翻译：

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131I-ixolaris作为治疗试剂的开发：转移性黑色素瘤临床前研究。

组织因子（TF）是一种凝血蛋白，在肿瘤的生长，侵袭和转移中起着重要的作用。Ixolaris是与TF结合的壁虱来源的非免疫原性分子，已证明对黑色素瘤小鼠模型具有体内抑制作用，包括初级生长和转移。这项工作旨在：I）用碘131（131I）开发高效，稳定的ixolaris标记技术；II）比较131I和131I-ixolaris在无肿瘤和带有黑素瘤的小鼠中的生物分布；III）评估131I-ixolaris是否可以用作抗转移剂。使用碘进行线虫放射性碘化，然后进行液相纸层析。测量标记稳定性和抗凝活性。在采用B16-F10细胞系的小鼠黑色素瘤模型中静脉注射游离131I或131I-ixolaris后，进行了成像研究。将动物分为三个实验组：第一个实验组D0在动物接种黑素瘤细胞的同一天接受9.25 MBq的131I-ixolaris单剂量。在第二组D15中，在诱导肿瘤后的第15天将9.25MBq的单剂量131I-ixolaris或游离131I应用于小鼠。第三组D1-D15接受了9.25 MBq的131I-ixolaris或131I的两个治疗剂量。体外研究表明131I-ixolaris在长达24小时内稳定，并保留了其对凝血的抑制活性。生物分布分析和转移分析表明，使用131I-ixolaris的所有治疗方案均有效，是最有效的双重治疗（D1 / D15）。明显地，用游离131I处理没有显示出抗转移作用。131I-ixolaris是一种有前景的转移性黑色素瘤治疗剂。