188Re-labeled GX1 dimer as a novel dual-functional probe targeting TGM2 for imaging and antiangiogenic therapy of gastric cancer

Eur J Pharm Biopharm. 2020 Sep:154:144-152. doi: 10.1016/j.ejpb.2020.07.015. Epub 2020 Jul 16.

Abstract

Purpose: The GX1 peptide (CGNSNPKSC) can specifically bind to TGM2 and possesses the ability to target the blood vessels of gastric cancer. This study intends to develop an integrated dual-functional probe with higher affinity, specificity and targeting and to characterize it in vivo and in vitro.

Methods: The dimer and tetramer of GX1 were prepared using cross-linked PEG and labeled with 99mTc. The best targeting probe [PEG-(GX1)2] was selected by gamma camera imaging in nude mouse models of gastric cancer. 188Re-PEG-(GX1)2 was prepared and characterized through cell binding analysis and competitive inhibition experiments, gamma camera imaging, MTT analysis and flow cytometry, BLI, immunohistochemistry, HE staining and biochemical analysis.

Results: PEG-(GX1)2 bound specifically to Co-HUVEC with higher affinity than GX1. 188Re-PEG-(GX1)2 had better ability to target gastric cancer in tumor-bearing nude mice and higher T/H ratios than 188Re-GX1. 188Re-PEG-(GX1)2 inhibited the growth of Co-HUVEC and induced apoptosis, and its effects were more robust than those of 188Re-GX1. BLI showed that 188Re-PEG-(GX1)2 inhibited tumor proliferation in vivo with a stronger effect than 188Re-GX1. Compared with 188Re-GX1, 188Re-PEG-(GX1)2 suppressed tumor angiogenesis and tumor cell proliferation and induced tumor cell apoptosis in vivo. The 188Re-PEG-(GX1)2 group did not cause visible changes in liver and kidney morphology and function in vivo.

Conclusion: The dimer of GX1 was synthesized by using cross-linked PEG, and then 188Re-PEG-(GX1)2 was prepared. This radiopharmaceutical played both diagnostic and therapeutic functions, and gamma camera imaging could be utilized to detect the distribution of drugs in vivo during treatment. Through a series of experiments in vitro and in vivo, the feasibility of the drug was confirmed, and these results laid the foundation for the subsequent development and application of GX1.

Keywords: (188)Re; Antiangiogenic therapy; GX1 dimer and TGM2; Gastric cancer.

MeSH terms

  • Angiogenesis Inhibitors / metabolism*
  • Angiogenesis Inhibitors / therapeutic use
  • Animals
  • Cell Line, Tumor
  • Female
  • GTP-Binding Proteins / metabolism*
  • Human Umbilical Vein Endothelial Cells / drug effects
  • Human Umbilical Vein Endothelial Cells / metabolism
  • Humans
  • Mice
  • Mice, Inbred BALB C
  • Mice, Nude
  • Molecular Imaging / methods*
  • Molecular Probes / metabolism
  • Peptide Fragments / metabolism*
  • Protein Glutamine gamma Glutamyltransferase 2
  • Radioisotopes / metabolism*
  • Rhenium / metabolism*
  • Stomach Neoplasms / drug therapy
  • Stomach Neoplasms / metabolism*
  • Stomach Neoplasms / pathology
  • Transglutaminases / metabolism*
  • Tumor Burden / drug effects
  • Tumor Burden / physiology

Substances

  • Angiogenesis Inhibitors
  • Molecular Probes
  • Peptide Fragments
  • Radioisotopes
  • TGM2 protein, human
  • Rhenium-188
  • Rhenium
  • Protein Glutamine gamma Glutamyltransferase 2
  • Transglutaminases
  • GTP-Binding Proteins