Development of chimeric and bifunctional antagonists for CLR/RAMP receptors

• Published in: PloS one Vol. 14; no. 5; p. e0216996
• Main Authors: Chang, Chia Lin, Hsu, Sheau Yu Teddy
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 31.05.2019; Public Library of Science (PLoS)
• Subjects: Acids; Adrenomedullin; Amino acids; Amino Acids - genetics; Analogs; Angiogenesis; Angiogenesis Inhibitors - chemistry; Angiogenesis Inhibitors - therapeutic use; Antibodies; Arthritis; Binding; Biocompatibility; Biology and Life Sciences; Biomedical materials; Blockage; Calcitonin gene-related peptide; Calcitonin Gene-Related Peptide Receptor Antagonists; Cell Proliferation - drug effects; Diabetic neuropathy; Headache; Hormones; Humans; Immunoglobulins; Lysine; Medicine and Health Sciences; Metastases; Metastasis; Migraine; Migraine Disorders - drug therapy; Migraine Disorders - genetics; Migraine Disorders - pathology; Morphogenesis; Neoplasm Metastasis; Neoplasms - drug therapy; Neoplasms - genetics; Neoplasms - pathology; Neovascularization, Pathologic - drug therapy; Neovascularization, Pathologic - genetics; Neovascularization, Pathologic - pathology; Nerve endings; Neuroendocrine tumors; Neuroendocrine Tumors - drug therapy; Neuroendocrine Tumors - genetics; Neuroendocrine Tumors - pathology; Neuropeptides; Neurotransmission; Osteoarthritis; Osteoarthritis - drug therapy; Osteoarthritis - genetics; Osteoarthritis - pathology; Pain; Peptide Hormones - genetics; Peptides; Placenta; Prostate cancer; Protein Domains - genetics; Receptor activity modifying proteins; Receptor Activity-Modifying Protein 1 - genetics; Receptor Activity-Modifying Protein 2 - antagonists & inhibitors; Receptor Activity-Modifying Protein 2 - chemistry; Receptor Activity-Modifying Protein 2 - genetics; Receptors; Research and Analysis Methods; Selectivity; Signaling; Somatostatin; Synovial joints; Therapy; Trigeminal ganglion; Tumor Microenvironment - drug effects; Tumors
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0216996

CGRP, adrenomedullin (ADM), and adrenomedullin 2 (ADM2) family peptides are important neuropeptides and hormones for the regulation of neurotransmission, vasotone, cardiovascular morphogenesis, vascular integrity, and feto‒placental development. These peptides signal through CLR/RAMP1, 2 and 3 receptor complexes. CLR/RAMP1, or CGRP receptor, antagonists have been developed for the treatment of migraine headache and osteoarthritis pain; whereas CLR/RAMP2, or ADM receptor, antagonists are being developed for the treatment of tumor growth/metastasis. Based on the finding that an acylated chimeric ADM/ADM2 analog potently stimulates CLR/RAMP1 and 2 signaling, we hypothesized that the binding domain of this analog could have potent inhibitory activity on CLR/RAMP receptors. Consistent with this hypothesis, we showed that acylated truncated ADM/ADM2 analogs of 27-31 residues exhibit potent antagonistic activity toward CLR/RAMP1 and 2. On the other hand, nonacylated analogs have minimal activity. Further truncation at the junctional region of these chimeric analogs led to the generation of CLR/RAMP1-selective antagonists. A 17-amino-acid analog (Antagonist 2-4) showed 100-fold selectivity for CLR/RAMP1 and was >100-fold more potent than the classic CGRP receptor antagonist CGRP8-37. In addition, we showed (1) a lysine residue in the Antagonist 2-4 is important for enhancing the antagonistic activity, (2) an analog consisted of an ADM sequence motif and a 12-amino-acid binding domain of CGRP exhibits potent CLR/RAMP1-inhibitory activity, and (3) a chimeric analog consisted of a somatostatin analog and an ADM antagonist exhibits dual activities on somatostatin and CLR/RAMP receptors. Because the blockage of CLR/RAMP signaling prevents migraine pain and suppresses tumor growth/metastasis, further studies of these analogs, which presumably have better access to the tumor microenvironment and nerve endings at the trigeminal ganglion and synovial joints as compared to antibody-based therapies, may lead to the development of better anti-CGRP therapy and alternative antiangiogenesis therapy. Likewise, the use of bifunctional somatostatin-ADM antagonist analogs could be a promising strategy for the treatment of high-grade neuroendocrine tumors by targeting an antiangiogenesis agent to the neuroendocrine tumor microenvironment.