Design of fluorogenic probes and fluorescent‐tagged inhibitors for γ‐glutamyl cyclotransferase

Abstract

A tumor-related protein, human chromosome 7 ORF 24 (C7orf24), is involved in regulation of the glutathione homeostasis cycle as a γ-glutamyl cyclotransferase (GGCT). The singular substrate preference of this enzyme had long hampered its chemical probe development. That is, substrate of GGCT is definitely 'γ-Glu-Xaa', where Xaa is an L-α-amino acid. Based on the structure of substrates and GGCT fluorogenic probes, LISA-4/101, we succesfully developed a fluorescent-tagged inhibitor, gKFA. These chemical tools will assist cancer-related researches in the future.

A Novel Prodrug of a γ‐Glutamylcyclotransferase Inhibitor Suppresses Cancer Cell Proliferation in vitro and Inhibits Tumor Growth in a Xenograft Mouse Model of Prostate Cancer

“…To evaluate the ability of GA to permeate the cell membrane and to identify a suitable prodrug structure, we designed and synthesized N α ‐glutaryl‐ N ϵ ‐nitrobenzoxadiazolyl‐ l ‐lysine ( N α ‐glutaryl‐Lys(NBD), gKFA) and several mono‐/diester analogues as temporary fluorescence‐labeled GA derivatives. The structures of the putative gKFA prodrugs were as follows: monomethyl esters (a mixture of Me‐gKFA and gKFA‐Me), dimethyl ester (Me‐gKFA‐Me), monopicolyl esters (a mixture of Pic‐gKFA and gKFA‐Pic), dipicolyl ester (Pic‐gKFA‐Pic), methyl‐medoxomil ester (Me‐gKFA‐MED), and methyl‐acetoxymethyl ester (Me‐gKFA‐AM).…”

“…Purity: 98.7 % (220 nm). The data are consistent with those reported earlier . Yield (monomethyl ester as mixture of two isomers, Me‐gKFA and gKFA‐Me): 21.1 mg, 48.2 μmol.…”

“…[15] Glutaryl-Lys(NBD) (gKFA):T he compound was prepared as described previously. [23] Simultaneous syntheses of Me-gKFA-Me and Me-gKFA:…”

“…The data are consistent with those reported earlier. [23] Yield (monomethyl ester as mixture of two isomers, Me-gKFAa nd gKFA-Me): 21. www.chemmedchem.org 466 mmol), and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC, 375 mL, 2.05 mmol) were dissolved in CHCl 3 (3 mL) and stirred for 5h at room temperature. Next, EtOAc was added to the reaction mixture and the organic layer was washed successively with sat.…”

Mechanisms of Tumor Growth Inhibition by Depletion of γ-Glutamylcyclotransferase (GGCT): A Novel Molecular Target for Anticancer Therapy

“…As the structure of an inhibitor of enzymatic activity often resembles the structure of the natural substrate of the enzyme, 18 compounds structurally similar to γ-glutamyl- l -amino acid were selected as candidates for GGCT inhibition. N -glutaryl- l -alanine (GA) was found to be the most potent inhibitor for GGCT by compound screening using the LISA-101 assay, a novel GGCT fluorogenic probe [ 33 , 34 ]. GA was an effective GGCT inhibitor in cell homogenates, but was unable to penetrate through the cell membranes.…”