Molecular characterisation of long-acting insulin analogues in comparison with human insulin, IGF-1 and insulin X10

• Published in: PloS one Vol. 7; no. 5; p. e34274
• Main Authors: Hansen, Bo F, Glendorf, Tine, Hegelund, Anne C, Lundby, Anders, Lützen, Anne, Slaaby, Rita, Stidsen, Carsten Enggaard
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 08-05-2012; Public Library of Science (PLoS)
• Subjects: Affinity; Analysis; Binding; Biology; Cancer; Cells, Cultured; Diabetes; Female; Fibroblasts; Humans; Hypoglycemic Agents - pharmacokinetics; Hypoglycemic Agents - pharmacology; Infrared radiation; Insulin; Insulin Detemir; Insulin Glargine; Insulin, Long-Acting - pharmacokinetics; Insulin, Long-Acting - pharmacology; Insulin, Regular, Human - pharmacokinetics; Insulin, Regular, Human - pharmacology; Insulin-like growth factor I; Insulin-Like Growth Factor I - analogs & derivatives; Insulin-Like Growth Factor I - pharmacokinetics; Insulin-Like Growth Factor I - pharmacology; Insulin-like growth factors; Isoforms; Life sciences; Ligands; Measurement methods; Medicine; Mitogenicity; Mitosis - drug effects; Phosphorylation; Phosphorylation - drug effects; Physiology; Protein Binding; Receptor mechanisms; Receptor, IGF Type 1 - genetics; Receptor, IGF Type 1 - metabolism; Receptors; Rodents; Smooth muscle; Stimulation; Studies; Denmark
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0034274

There is controversy with respect to molecular characteristics of insulin analogues. We report a series of experiments forming a comprehensive characterisation of the long acting insulin analogues, glargine and detemir, in comparison with human insulin, IGF-1, and the super-mitogenic insulin, X10.
We measured binding of ligands to membrane-bound and solubilised receptors, receptor activation and mitogenicity in a number of cell types.
Detemir and glargine each displayed a balanced affinity for insulin receptor (IR) isoforms A and B. This was also true for X10, whereas IGF-1 had a higher affinity for IR-A than IR-B. X10 and glargine both exhibited a higher relative IGF-1R than IR binding affinity, whereas detemir displayed an IGF-1R:IR binding ratio of ≤ 1. Ligands with high relative IGF-1R affinity also had high affinity for IR/IGF-1R hybrid receptors. In general, the relative binding affinities of the analogues were reflected in their ability to phosphorylate the IR and IGF-1R. Detailed analysis revealed that X10, in contrast to the other ligands, seemed to evoke a preferential phosphorylation of juxtamembrane and kinase domain phosphorylation sites of the IR. Sustained phosphorylation was only observed from the IR after stimulation with X10, and after stimulation with IGF-1 from the IGF-1R. Both X10 and glargine showed an increased mitogenic potency compared to human insulin in cells expressing many IGF-1Rs, whereas only X10 showed increased mitogenicity in cells expressing many IRs.
Detailed analysis of receptor binding, activation and in vitro mitogenicity indicated no molecular safety concern with detemir.