Background: Conjugation to clinical-grade tumor penetrating iRGD peptide is a widely used strategy to improve tumor homing, extravasation, and penetration of cancer drugs and tumor imaging agents. The C domain of the extracellular matrix molecule Tenascin-C (TNC-C) is upregulated in solid tumors and represents an attractive target for clinical-grade single-chain antibody- based vehicles for tumor delivery drugs and imaging agents.
Objective: To study the effect of C-terminal genetic fusion of the iRGD peptide to recombinant anti- TNC-C single-chain antibody clone G11 on systemic tumor homing and extravasation.
Methods: Enzyme-linked immunosorbent assay was used to study the interaction of parental and iRGD-fused anti-TNC-C single-chain antibodies with C domain of tenascin-C and αVβ3 integrins. For systemic homing studies, fluorescein-labeled ScFV G11-iRGD and ScFV G11 antibodies were administered in U87-MG glioblastoma xenograft mice, and their biodistribution was studied by confocal imaging of tissue sections stained with markers of blood vessels and Tenascin C immunoreactivity.
Results: In a cell-free system, iRGD fusion to ScFV G11 conferred the antibody has a robust ability to bind αVβ3 integrins. The fluorescein labeling of ScFV G11-iRGD did not affect its target binding activity. In U87-MG mice, iRGD fusion to ScFV G11 antibodies improved their homing to tumor blood vessels, extravasation, and penetration of tumor parenchyma.
Conclusion: The genetic fusion of iRGD tumor penetrating peptide to non-internalizing affinity targeting ligands may improve their tumor tropism and parenchymal penetration for more efficient delivery of imaging and therapeutic agents into solid tumor lesions.
[http://dx.doi.org/10.1126/science.1183057] [PMID: 20378772]
[http://dx.doi.org/10.1016/j.jconrel.2014.12.039] [PMID: 25553823]
[http://dx.doi.org/10.1016/j.biomaterials.2019.119373] [PMID: 31374479]
[http://dx.doi.org/10.1093/protein/gzl033] [PMID: 16928692]
[http://dx.doi.org/10.2967/jnumed.106.036046] [PMID: 17401095]
[http://dx.doi.org/10.1073/pnas.1114518108] [PMID: 21969599]
[http://dx.doi.org/10.1016/j.biomaterials.2014.06.042] [PMID: 25023394]
[http://dx.doi.org/10.1016/j.jconrel.2019.06.018] [PMID: 31255690]
[http://dx.doi.org/10.1038/bjc.2014.49] [PMID: 24556620]
[http://dx.doi.org/10.1158/0008-5472.CAN-15-0395] [PMID: 26239478]
[http://dx.doi.org/10.1172/JCI92284] [PMID: 28414297]
[http://dx.doi.org/10.1096/fj.07-8865com] [PMID: 18048579]
[http://dx.doi.org/10.1074/jbc.M113.463000] [PMID: 23818524]