GNS561, a clinical-stage PPT1 inhibitor, is efficient against hepatocellular carcinoma <i>via</i> modulation of lysosomal functions
Creators: name: Brun, Sonia
name: Bestion, Eloïne
name: Raymond, Eric
name: Bassissi, Firas
name: Jilkova, Zuzana Macek
name: Mezouar, Soraya
name: Rachid, Madani
name: Novello, Marie
name: Tracz, Jennifer
name: Hamaï, Ahmed
name: Lalmanach, Gilles
name: Vanderlynden, Lise
name: Legouffe, Raphael
name: Stauber, Jonathan
name: Schubert, Thomas
name: Plach, Maximilian G.
name: Courcambeck, Jérôme
name: Drouot, Cyrille
name: Jacquemot, Guillaume
name: Serdjebi, Cindy
name: Roth, Gael
name: Baudoin, Jean-Pierre
name: Ansaldi, Christelle
name: Decaens, Thomas
name: Halfon, Philippe
Publisher: name: Taylor & Francis
Year: 2021
Subjects: Biophysics
Biochemistry
Physical Sciences not elsewhere classified
Cell Biology
Pharmacology
Biotechnology
Chemical Sciences not elsewhere classified
Biological Sciences not elsewhere classified
Cancer

description: Hepatocellular carcinoma is the most frequent primary liver cancer. Macroautophagy/autophagy inhibitors have been extensively studied in cancer but, to date, none has reached efficacy in clinical trials. In this study, we demonstrated that GNS561, a new autophagy inhibitor, whose anticancer activity was previously linked to lysosomal cell death, displayed high liver tropism and potent antitumor activity against a panel of human cancer cell lines and in two hepatocellular carcinoma in vivo models. We showed that due to its lysosomotropic properties, GNS561 could reach and specifically inhibited its enzyme target, PPT1 (palmitoyl-protein thioesterase 1), resulting in lysosomal unbound Zn<sup>2+</sup> accumulation, impairment of cathepsin activity, blockage of autophagic flux, altered location of MTOR (mechanistic target of rapamycin kinase), lysosomal membrane permeabilization, caspase activation and cell death. Accordingly, GNS561, for which a global phase 1b clinical trial in liver cancers was just successfully achieved, represents a promising new drug candidate and a hopeful therapeutic strategy in cancer treatment. <b>Abbreviations</b>: ANXA5:annexin A5; ATCC: American type culture collection; BafA1: bafilomycin A<sub>1</sub>; BSA: bovine serum albumin; CASP3: caspase 3; CASP7: caspase 7; CASP8: caspase 8; CCND1: cyclin D1; CTSB: cathepsin B; CTSD: cathepsin D; CTSL: cathepsin L; CQ: chloroquine; iCCA: intrahepatic cholangiocarcinoma; DEN: diethylnitrosamine; DMEM: Dulbelcco’s modified Eagle medium; FBS: fetal bovine serum; FITC: fluorescein isothiocyanate; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; HCC: hepatocellular carcinoma; HCQ: hydroxychloroquine; HDSF: hexadecylsulfonylfluoride; IC<sub>50</sub>: mean half-maximal inhibitory concentration; LAMP: lysosomal associated membrane protein; LC3-II: phosphatidylethanolamine-conjugated form of MAP1LC3; LMP: lysosomal membrane permeabilization; MALDI: matrix assisted laser desorption ionization; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MKI67: marker of proliferation Ki-67; MTOR: mechanistic target of rapamycin kinase; MRI: magnetic resonance imaging; NH<sub>4</sub>Cl: ammonium chloride; NtBuHA: N-tert-butylhydroxylamine; PARP: poly(ADP-ribose) polymerase; PBS: phosphate-buffered saline; PPT1: palmitoyl-protein thioesterase 1; SD: standard deviation; SEM: standard error mean; vs, versus; Zn<sup>2+</sup>: zinc ion; Z-Phe: Z-Phe-Tyt(tBu)-diazomethylketone; Z-VAD-FMK: carbobenzoxy-valyl-alanyl-aspartyl-[O-methyl]- fluoromethylketone.