Comparison of tumor neovasculature-targeted paramagnetic nanoliposomes for MRI in mice xenograft models

Neovasculature imaging is a promising approach for tumor diagnosis. We constructed tumor neovasculature targeted paramagnetic nanoliposomes with RGD10, F56, and K237 peptides, which can bind to Integrin αvβ3 and VEGFR-1, VEGFR-2, respectively, and compared their potential value as MRI contrast agents for detecting small tumors in animal models.Peptide-Ahx-palmitic acid conjugate was synthesized using Fmoc solid-phase synthesis chemistry. Targeted paramagnetic nanoliposomes were prepared by the thin film dispersion-sonication method. The tumor signal enhancements of liposome particles were evaluated by MRI in a xenograft mice model.The apparent affinity constants of RGD10, K237, and F56 peptides binding to their cell receptors were 9.15 × 10(7), 6.01 × 10(7), and 3.85 × 10(7) mol/L, respectively. RGD10 and K237 targeted paramagnetic nanoliposomes have shown much greater tumor-specific MRI signal enhancement in xenograft of the nude mice compared to F56 targeted paramagnetic nanoliposome. Tumor signal enhancement rate (SER %) increased 2.21 ± 0.09 and 1.82 ± 0.05 fold, respectively, for RGD10 and K237 compared to non-targeted control in T1 weighted MR image.RGD10 and K237 targeted paramagnetic nanoliposomes can be developed as potential tumor-specific MRI contrast agents and are helpful for tumor detection.