TMVP1446/GS5, a novel peptide with improved metabolic stability relative to TMVP1446, targets VEGFR-3 for primary tumor and lymph node metastases detection in vivo

TMVP1446 is a novel peptide independently screened by our research team, which can target tumors and lymph node metastases in vivo due to its specific binding to VEGFR-3 protein. However, its poor stability in vivo greatly limits its clinical translation. Herein, through a series of modifications to protect the TMVP1446 peptide from protease degradation, TMVP1446/GS5, a novel 12-amino acid peptide that retains specific binding to VEGFR-3 and exhibits improved stability in vivo , was designed. The low-millimolar dissociation constant (KD) of VEGFR-3 binding, VEGFR-3-dependent binding to cells, and competitive binding with TMVP1446 confirmed the specific affinity of TMVP1446/GS5 to VEGFR-3 in vitro . TMVP1446/GS5 was conjugated to the near-infrared (NIR) dye Cy7 for visualization of tumor and lymph node metastases in vivo . Surprisingly, despite having nearly the same KD value as TMVP1446, TMVP1446/GS5-Cy7 exhibited much stronger fluorescence signals in vivo in tumor and lymph node metastases. This paradoxical result further confirmed that TMVP1446/GS5 showed increased in vivo metabolic stability relative to TMVP1446. Additionally, TMVP1446/GS5 exhibited good biocompatibility in vivo safety assessment experiments. In conclusion, the novel peptide TMVP1446/GS5, with a specific binding affinity to VEGFR-3 and improved stability compared to TMVP1446, has great potential in the clinical application of fluorescence imaging of tumors and lymph node metastases.