Design of MC1R Selective γ‑MSH Analogues with Canonical Amino Acids Leads to Potency and Pigmentation

• Published in: Journal of medicinal chemistry 2017-11, Vol.60 (22), p.9320-9329
• Main Authors: Zhou, Yang, Mowlazadeh Haghighi, Saghar, Zoi, Ioanna, Sawyer, Jonathon R, Hruby, Victor J, Cai, Minying
• Format: Article
• Language: English
• Subjects: alpha-MSH - administration & dosage; alpha-MSH - analogs & derivatives; alpha-MSH - chemical synthesis; alpha-MSH - pharmacokinetics; alpha-MSH - pharmacology; Animals; Drug Stability; Half-Life; HEK293 Cells; Humans; Hypothalamic Hormones - administration & dosage; Hypothalamic Hormones - chemical synthesis; Hypothalamic Hormones - pharmacokinetics; Hypothalamic Hormones - pharmacology; Iodine Radioisotopes; Ligands; Melanocyte-Stimulating Hormones - administration & dosage; Melanocyte-Stimulating Hormones - chemical synthesis; Melanocyte-Stimulating Hormones - pharmacokinetics; Melanocyte-Stimulating Hormones - pharmacology; Molecular Conformation; Molecular Docking Simulation; Receptor, Melanocortin, Type 1 - agonists; Receptor, Melanocortin, Type 1 - chemistry; Reptiles; Skin Pigmentation - drug effects
• ISSN: 0022-2623; 1520-4804
• DOI: 10.1021/acs.jmedchem.7b01295

Melanoma is a lethal form of skin cancer. Skin pigmentation, which is regulated by the melanocortin 1 receptor (MC1R), is an effective protection against melanoma. However, the endogenous MC1R agonists lack selectivity for the MC1R and thus can have side effects. The use of noncanonical amino acids in previous MC1R ligand development raises safety concerns. Here we report the development of the first potent and selective hMC1R agonist with only canonical amino acids. Using γ-MSH as a template, we developed a peptide, [Leu3, Leu7, Phe8]-γ-MSH-NH2 (compound 5), which is 16-fold selective for the hMC1R (EC50 = 4.5 nM) versus other melanocortin receptors. Conformational studies revealed a constrained conformation for this linear peptide. Molecular docking demonstrated a hydrophobic binding pocket for the melanocortin 1 receptor. In vivo pigmentation study shows high potency and short duration. [Leu3, Leu7, Phe8]-γ-MSH-NH2 is ideal for inducing short-term skin pigmentation without sun for melanoma prevention.