Autor según el artículo: Tramonti, Angela; Cuyas, Elisabet; Encinar, Jose; Pietzke, Matthias; Paone, Alessio; Verdura, Sara; Arbusa, Aina; Martin-Castillo, Begona; Giardina, Giorgio; Joven, Jorge; Vazquez, Alexei; Contestabile, Roberto; Cutruzzola, Francesca; Menendez, Javier;
Departamento: Medicina i Cirurgia
Autor/es de la URV: Joven Maried, Jorge
Palabras clave: Vitamin-b12 Target Serine hydroxymethyltransferase Serine Resistance One-carbon metabolism Glycine Folate Enzyme Deficiency Cytosolic serine hydroxymethyltransferase Catabolism
Resumen: Simple Summary The mitochondrial enzyme serine hydroxymethyltransferase (SHMT2), which converts serine into glycine and generates 1C units for cell growth, is one of the most consistently overexpressed metabolic enzymes in cancer. Here, we reveal that the anti-diabetic biguanide metformin operates as a novel class of non-catalytic SHMT2 inhibitor that disrupts the pyridoxal-5 '-phosphate (PLP)-dependent SHMT2 oligomerization process and ultimately SHMT2 activity. As SHMT2 inhibitors have not yet reached the clinic, these findings may aid the rational design of PLP-competitive SHMT2 inhibitors based on the biguanide skeleton of metformin. The anticancer actions of the biguanide metformin involve the functioning of the serine/glycine one-carbon metabolic network. We report that metformin directly and specifically targets the enzymatic activity of mitochondrial serine hydroxymethyltransferase (SHMT2). In vitro competitive binding assays with human recombinant SHMT1 and SHMT2 isoforms revealed that metformin preferentially inhibits SHMT2 activity by a non-catalytic mechanism. Computational docking coupled with molecular dynamics simulation predicted that metformin could occupy the cofactor pyridoxal-5 '-phosphate (PLP) cavity and destabilize the formation of catalytically active SHMT2 oligomers. Differential scanning fluorimetry-based biophysical screening confirmed that metformin diminishes the capacity of PLP to promote the conversion of SHMT2 from an inactive, open state to a highly ordered, catalytically competent closed state. CRISPR/Cas9-based disruption of SHMT2, but not of SHMT1, prevented metformin from inhibiting total SHMT activity in cancer cell lines. Isotope tracing studies in SHMT1 knock-out cells confirmed that metformin decreased the SHMT2-channeled serine-to-formate flux and restricted the formate utilization in thymidylate synthesis upon overexpression of the metformin-unresponsive yeast equivalent of mitochondrial complex I (mCI). While maintaining its capacity to inhibit mitochondrial oxidative phosphorylation, metformin lost its cytotoxic and antiproliferative activity in SHMT2-null cancer cells unable to produce energy-rich NADH or FADH(2) molecules from tricarboxylic acid cycle (TCA) metabolites. As currently available SHMT2 inhibitors have not yet reached the clinic, our current data establishing the structural and mechanistic bases of metformin as a small-molecule, PLP-competitive inhibitor of the SHMT2 activating oligomerization should benefit future discovery of biguanide skeleton-based novel SHMT2 inhibitors in cancer prevention and treatment.
Áreas temáticas: Oncology Medicina iii Cancer research
Acceso a la licencia de uso: https://creativecommons.org/licenses/by/3.0/es/
Direcció de correo del autor: jorge.joven@urv.cat
Identificador del autor: 0000-0003-2749-4541
Fecha de alta del registro: 2023-02-19
Versión del articulo depositado: info:eu-repo/semantics/publishedVersion
Enlace a la fuente original: https://www.mdpi.com/2072-6694/13/16/4009
URL Documento de licencia: http://repositori.urv.cat/ca/proteccio-de-dades/
Referencia al articulo segun fuente origial: Cancers. 13 (16):
Referencia de l'ítem segons les normes APA: Tramonti, Angela; Cuyas, Elisabet; Encinar, Jose; Pietzke, Matthias; Paone, Alessio; Verdura, Sara; Arbusa, Aina; Martin-Castillo, Begona; Giardina, G (2021). Metformin Is a Pyridoxal-5 '-phosphate (PLP)-Competitive Inhibitor of SHMT2. Cancers, 13(16), -. DOI: 10.3390/cancers13164009
DOI del artículo: 10.3390/cancers13164009
Entidad: Universitat Rovira i Virgili
Año de publicación de la revista: 2021
Tipo de publicación: Journal Publications
Repositori URV