Modulating the Efficacy of Carbonic Anhydrase Inhibitors through Fluorine Substitution

Abstract

The insertion of fluorine atoms and/or fluoroalkyl groups can lead to many beneficial effects in biologically active molecules, such as enhanced metabolic stability, bioavailability, lipophilicity, and membrane permeability, as well as a strengthening of protein–ligand binding interactions. However, this “magic effect” of fluorine atom(s) insertion can often be meaningless. Taking advantage of the wide range of data coming from the quest for carbonic anhydrase (CA) fluorinated inhibitors, this Minireview attempts to give “general guidelines” on how to wisely insert fluorine atom(s) within an inhibitor moiety to precisely enhance or disrupt ligand–protein interactions, depending on the target location of the fluorine substitution in the ligand. Multiple approaches such as ITC, kinetic and inhibition studies, X‐ray crystallography, and NMR spectroscopy are useful in dissecting single binding contributions to the overall observed effect. The exploitation of innovative directions made in the field of protein and ligand‐based fluorine NMR screening is also discussed to avoid misconduct and finely tune the exploitation of selective fluorine atom insertion in the future.

Small Molecule Alkoxy Oriented Selectiveness on Human Carbonic Anhydrase II and IX Inhibition

“…The inhibition constants were obtained by non‐linear least‐squares methods using PRISM 3 and the Cheng‐Prusoff equation as reported earlier and represent the mean from at least three different determinations. All CA isoforms were recombinant proteins obtained inhouse, as reported earlier [5,8,10–12] …”

“…All CA isoforms were recombinant proteins obtained inhouse, as reported earlier. [5,8,[10][11][12] Carbonic anhydrase IX-mimic design Carbonic Anhydrase IX-mimic was originally designed and engineered by site directed mutagenesis of hCA II by Genis et al [22] and further developed by Pinard et al. [23] Amino acid substitutions within the active site of hCA II (A65S, N67Q, E69T, I91L, F131V, K170D, and L204A) were made to represent the active site of hCA IX, to create hCA IX-mimic.…”

“…Whereas, small molecules can readily be use as valid alternatives, although they maintain to some extent a certain degree of un‐selectivity which may be useful and properly enhanced/directed when multiple and/or functional cooperative biological targets for a disease are addressed (i. e. polypharmacology). In this context our groups largely contributed to decipher at the atomic level the principles governing the binding modes of variegate molecular scaffolds onto the human Carbonic Anhydrases (hCAs, EC 4.2.1.1) which are linked to many diseases, such as cancers [8–13] . This study reports for the first‐time deep structure‐activity relationships (SARs) referred to classical hCA inhibitors (CAIs) of the primary sulfonamide type bearing ureido alkoxy tails.…”

“…In this context our groups largely contributed to decipher at the atomic level the principles governing the binding modes of variegate molecular scaffolds onto the human Carbonic Anhydrases (hCAs, EC 4.2.1.1) which are linked to many diseases, such as cancers. [8][9][10][11][12][13] This study reports for the first-time deep structure-activity relationships (SARs) referred to classical hCA inhibitors (CAIs) of the primary sulfonamide type bearing ureido alkoxy tails. The restrained molecular dimensions along with the high flexibility of the alkyl chains introduced offered the possibility to better consider such molecules as orthosteric probes highly adaptable to the hCAs configuration clefts and thus highly valuable to extract effective interactions occurring between ligands and target proteins.…”

Coumarins inhibit η-class carbonic anhydrase from Plasmodium falciparum

“…Thus, a rather large number of drug design studies were performed over the last decade 2–4 using both natural products as well as synthetic coumarins as starting point, which established the fact that coumarjns are among the most effective and isoform-selective CAIs known to date 1–4 . Indeed, derivatives with selectivity for all human isoforms have been reported so far, although the largest number of studies and derivatives investigated to date were designed for targeting the transmembrane, cancer-associated isoforms hCA IX and XII, which are validated antitumor/antimetastatic drug targets 5 , 6 .…”