New anthranilic acid based antagonists with high affinity and selectivity for the human cholecystokinin receptor 1 (hCCK1-R).

The anthranilic acid diamides represent the most recent class of nonpeptide CCK(1) receptor (CCK(1)-R) antagonists. Herein we describe the second phase of the anthranilic acid C-terminal optimization using nonproteinogenic amino acids containing a phenyl ring in their side chain. The Homo-Phe derivative 2 (VL-0797) enhanced 12-fold the affinity for the rat CCK(1)-R affinity and 15-fold for the human CCK(1)-R relative to the reference compound 12 (VL-0395).

2D-QSAR and 3D-QSAR/CoMFA analyses of the N-terminal substituted anthranilic acid based CCK(1) receptor antagonists: 'Hic Rhodus, hic saltus'.

A research is presented on quantitative structure-activity relationship (QSAR) studies on the more recent class of non-peptidic CCK(1) receptor antagonists. Our results suggest that the balance of hydrophobicity and volume dependent polarizability term plays a key role in the antagonism of CCK(1) receptor. The size of the substitution of ligands at particular position which induce steric fit is crucial as well as their hydrophobic contribution.

Anthranilic acid based CCK1 receptor antagonists: blocking the receptor with the same 'words' of the endogenous ligand.

The anthranilic acid diamides represent the more recent class of nonpeptide CCK(1) receptor antagonists. This class is characterized by the presence of anthranilic acid, used as a molecular scaffold, and two pharmacophores selected from the C-terminal tetrapeptide of CCK. The lead compound coded VL-0395, endowed with sub-micromolar affinity towards CCK(1) receptors, was characterized by the presence of Phe and 2-indole moiety at the C- and N-termini of anthranilic acid, respectively.

Anthranilic acid based CCK1 receptor antagonists and CCK-8 have a common step in their "receptor desmodynamic processes".

The interaction between the 1-47 N-terminus of the CCK(1)-R and the anthranilic acid based antagonists has been investigated by fluorescence spectroscopy. These antagonists interact with W39 of the N-terminal domain of the CCK(1)-R like that of the endogenous ligand CCK-8. This specific interaction was not found in other nonpeptide ligands of the CCK(1)-R.

Anthranilic acid based CCK1 receptor antagonists: preliminary investigation on their second "touch point".

In this phase of structure-affinity relationship study of VL-0395, a new anthranilic acid based CCK1 selective antagonist, we propose a series of unnatural aminoacidic derivatives. The result of this work is the identification of a new CCK ligand, which possesses an affinity (IC50 = 35 nm) one order of magnitude greater than the lead and, as a general rule, it points out how the hypothesized receptorial pocket which accommodates the Phe residue allows much more structural modification than that interacting with the N-terminal group. Hence, the modification of the C-terminal pharmacophoric group of our lead VL-0395 can not only enhance the affinity of anthranilic acid derivatives but can modulate the selectivity for one CCK receptor subtype or afford mixed antagonists.

Anthranilic acid based CCK1 antagonists: the 2-indole moiety may represent a "needle" according to the recent homonymous concept.

Recently we described an innovative class of non-peptide CCK(1) antagonists keeping appropriate pharmacophoric groups on the anthranilic acid employed as a molecular scaffold. The lead compound obtained, VL-0395, characterized by the presence of Phe and the 2-indole moiety at the C- and N-termini of anthranilic acid, respectively, is endowed with submicromolar affinity towards CCK(1) receptors. Thus, we have prepared and tested on CCK receptors a library of VL-0395 analogues in order to investigate the precise topological and essential key interactions of the 2-indole group of the lead with the CCK(1) receptor.

Anthranilic acid derivatives: a new class of non-peptide CCK1 receptor antagonists.

Having successfully obtained new CCK(1) ligands holding appropriate groups on the anthranilic acid dimer used as molecular scaffold we were interested in increasing their micromolar affinity for the CCK(1) receptors by modifying the spatial relationship of the main pharmacophoric groups. Since, we have proposed simplified analogues reducing the anthranilic acid dimer to a monomer. In this stage of our research program we have prepared and tested on CCK receptors a series of N-substituted anthranilic acid derivatives keeping a Phe residue at the C-terminal site.