Gastrin releasing peptide antagonists with improved potency and stability
摘要:
Gastrin releasing peptide (GRP) is a 27 amino acid peptide hormone which is homologous to the amphibian peptide bombesin. Two series of novel GRP antagonists were developed by C-terminal modification of N-acetyl-GRP-20-27 amide. Peptide derivatives within each series resist enzymatic degradation in serum and exhibit strong affinity for the GRP receptor. The first series of compounds replaces the Leu26-Met27 region of GRP with an alkyl ether moiety. One member of this series, N-acetyl-GRP-20-25-NH-[(S)-1-ethoxy-4-methyl-2-pentane], specifically blocked radiolabeled GRP binding with an IC50 of 6 nM. In the second series of antagonists the oxygen of the ether moiety is replaced with a methylene group, resulting in GRP antagonists which are equipotent to native GRP in receptor binding assays (IC50 = 2 nM) and are also resistant to proteolytic degradation in vitro. All of the C-terminally modified peptides tested blocked GRP-stimulated mitogenesis in Swiss 3T3 mouse fibroblasts. Representative compounds also blocked GRP-induced elevation of [Ca2+]i in human SCLC cells, and inhibited GRP-independent release of gastrin in vivo.
A Convenient and Versatile Synthesis of Chiral Aliphatic and Allylic Amines
作者:Walfred S. Saari、Thorsten E. Fisher
DOI:10.1055/s-1990-26900
日期:——
Preparation of optically pure aliphatic and allylic amines from amino acids is described. Wittig olefination of α-Boc-amino aldehydes affords Boc-protected allylic amines which can be deprotected to the corresponding chiral unsaturated amines. Catalytic reduction of the Wittig product prior to deprotection affords aliphatic amines of high optical purity.
Small cell lung carcinoma (SCLC) cells contain gastrin releasing peptide (GRP) receptors. The response of the cells to GRP is rapid growth. We have found a group of peptide derivatives that act as GRP antagonists by blocking the binding of GRP to its receptor thereby inhibiting the growth of cells that are sensitive to the growth promoting activity of GRP.