Evaluation of a novel Arg-Gly-Asp-conjugated α-melanocyte stimulating hormone hybrid peptide for potential melanoma therapy.

Abstract

UNLABELLED:

The purpose of this study was to determine whether Arg-Gly-Asp (RGD)-conjugated α-melanocyte stimulating hormone (α-MSH) hybrid peptide could be employed to target melanocortin-1 (MC1) receptor for potential melanoma therapy.

METHODS:

The RGD motif {cyclic(Arg-Gly-Asp-DTyr-Asp)} was coupled to [Cys(3,4,10), DPhe(7), Arg(11)]α-MSH(3-13) {(Arg(11))CCMSH} to generate RGD-Lys-(Arg(11))CCMSH hybrid peptide. The MC1 receptor binding affinity of RGD-Lys-(Arg(11))CCMSH was determined in B16/F1 melanoma cells. The internalization and efflux, melanoma targeting and pharmacokinetic properties and single photon emission computed tomography/CT (SPECT/CT) imaging of (99m)Tc-RGD-Lys-(Arg(11))CCMSH were determined in B16/F1 melanoma cells and melanoma-bearing C57 mice. Clonogenic cytotoxic effect of RGD-Lys-(Arg(11))CCMSH was examined in B16/F1 melanoma cells.

RESULTS:

RGD-Lys-(Arg(11))CCMSH displayed 2.1 nM MC1 receptor binding affinity. (99m)Tc-RGD-Lys-(Arg(11))CCMSH showed rapid internalization and extended retention in B16/F1 cells. The cellular uptake of (99m)Tc-RGD-Lys-(Arg(11))CCMSH was MC1 receptor-mediated. (99m)Tc-RGD-Lys-(Arg(11))CCMSH exhibited high tumor uptake (14.83 ± 2.94% ID/g 2 h postinjection) and prolonged tumor retention (7.59 ± 2.04% ID/g 24 h postinjection) in B16/F1 melanoma-bearing mice. Nontarget organ uptakes were generally low except for the kidneys. Whole-body clearance of (99m)Tc-RGD-Lys-(Arg(11))CCMSH was rapid, with approximately 62% of the injected radioactivity cleared through the urinary system by 2 h postinjection. Flank melanoma tumors were clearly imaged by small animal SPECT/CT using (99m)Tc-RGD-Lys-(Arg(11))CCMSH as an imaging probe 2 h postinjection. Single treatment (3 h incubation) with 100 nM of RGD-Lys-(Arg(11))CCMSH significantly (p < 0.05) decreased the clonogenic survival of B16/F1 cells by 65% compared to the untreated control cells.

CONCLUSION:

Favorable melanoma targeting property of (99m)Tc-RGD-Lys-(Arg(11))CCMSH and remarkable cytotoxic effect of RGD-Lys-(Arg(11))CCMSH in B16/F1 cells warranted the further evaluation of (188)Re-labeled α-MSH hybrid peptides as novel therapeutic peptides for melanoma treatment once the strategies of amino acid coinjection or structural modification of peptide sequence substantially reduce the renal uptake.

• Authors: Jianquan Yang, Haixun Guo, Fabio Gallazzi, Marianne Berwick, R Steven Padilla, Yubin Miao
• Journal: Bioconjugate chemistry (Bioconjug Chem) Vol. 20 Issue 8 Pg. 1634-42 (Aug 19 2009) ISSN: 1520-4812 [Electronic] United States
• PMID: 19552406 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)

Chemical References

• Antineoplastic Agents
• Oligopeptides
• alpha-MSH
• Technetium
• arginyl-glycyl-aspartic acid

Topics

• Animals
• Antineoplastic Agents (chemical synthesis, chemistry, pharmacology, therapeutic use)
• Cell Survival (drug effects)
• Female
• Melanoma, Experimental (drug therapy)
• Mice
• Mice, Inbred C57BL
• Oligopeptides (chemistry)
• Structure-Activity Relationship
• Technetium (chemistry)
• Tissue Distribution
• Xenograft Model Antitumor Assays
• alpha-MSH (chemistry, pharmacology, therapeutic use)