Internalization of RGD peptide conjugates of near-infrared fluorescent probes in different cell lines occurs via different integrin receptor subtypes

S. Bloch; B. Xu; Y. Ye; K. Liang; S. Achilefu

doi:10.1117/12.647811

14 February 2006 Internalization of RGD peptide conjugates of near-infrared fluorescent probes in different cell lines occurs via different integrin receptor subtypes

S. Bloch, B. Xu, Y. Ye, K. Liang, S. Achilefu

Author Affiliations +

Proceedings Volume 6097, Optical Molecular Probes for Biomedical Applications; 60970H (2006) https://doi.org/10.1117/12.647811
Event: SPIE BiOS, 2006, San Jose, California, United States

Abstract

Expression of integrin α_vβ₃ is upregulated in a number of cancers including colon, pancreas, lung and breast. Previous studies demonstrated that near infrared (NIR) fluorescent probes designed to target α_vβ₃ accumulated both in vitro and in vivo in α_vβ₃-positive tumor cells. To evaluate the selectivity of some NIR-labeled RGD peptides for α_vβ₃, the molecular probes were incubated in different cells, including the α_vβ₃-positive U87 and A549 cells, and α_vβ₃-negative HT29 cells. Whereas the RGD compounds tested internalized in the A549 cells, their uptake by the HT29 cell line, which is positive for α_vβ₅ and α_vβ₆, was low. The uptake of these probes in U87 depended on the structural features of the compounds. Further studies with functional blocking antibodies showed that the internalization in the α_vβ₃-positive cells may be mediated by different integrin receptor subtypes. The preliminary results suggest that the internalization of linear RGD peptides is mediated by the α_vβ₃ heterodimer but rearrangement of the peptide sequence could alter the selectivity of the molecular probes for different integrin subunits in the dimeric α and β proteins. Thus, a careful choice of RGD peptides can be used to monitor the functional status of different integrins in cells and tissues.

Citation Download Citation

S. Bloch, B. Xu, Y. Ye, K. Liang, and S. Achilefu "Internalization of RGD peptide conjugates of near-infrared fluorescent probes in different cell lines occurs via different integrin receptor subtypes", Proc. SPIE 6097, Optical Molecular Probes for Biomedical Applications, 60970H (14 February 2006); https://doi.org/10.1117/12.647811

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