Fusion protein tTF-EG3287 induces occlusion of tumor vessels and impairs tumor growth in human colon caner.

The problems including narrow indications, low drug loading, and difficulty in intervention, severely affect the clinical efficacy of anti-tumor embolization. Here, we designed a novel tTF-EG3287 protein consisting of the truncated tissue factor (tTF) fused with the bicyclic polypeptide which was encoded by exons 7 and 8 for accurately localizing to the tumor vascular endothelial cells (EG3287). This study was aimed to explore its anti-cancer effect. Gene sequencing was used to verify the fusion gene. SDS-PAGE gel was used to confirm the optimal induction time and concentration of tTF-EG3287. Nickel affinity chromatography column was used to purify the fusion protein. Confocal microscopy was used to assess the target activity of tTF-EG3287 on colon cancer cells in vitro. Thrombelastography assay was used to identify the procoagulant activity of tTF-EG3287. In vivo experiments, the specific localization of tTF-EG3287 in tumor tissues and the effect of tTF-EG3287 on tumor thrombosis were further detected through in vivo imaging and HE staining, respectively. The tTF-EG3287 fusion protein was efficiently purified by nickel-affinity chromatography column. Moreover, tTF-EG3287 fusion protein showed the strongly coagulation activity and the specifically binding ability to the cell surface of colon cancer. In vivo, tTF-EG3287 was stably and persistently accumulated in tumor tissues, and specifically induced mixed thrombus formation in tumor vessels, and then impaired tumor growth (tumor inhibition rate=79.2%, p<0.01). Our data proved that the fusion protein tTF-EG3287 could be used as a novel and promising anti-cancer strategy and have the great potential value for clinical applications.