title: Cross-Talk between Alternatively Spliced UGT1A Isoforms and Colon Cancer Cell Metabolism.
abstract: Alternative splicing at the human glucuronosyltransferase 1 gene locus (UGT1) produces alternate isoforms UGT1A_i2s that control glucuronidation activity through protein-protein interactions. Here, we hypothesized that UGT1A_i2s function as a complex protein network connecting other metabolic pathways with an influence on cancer cell metabolism. This is based on a pathway enrichment analysis of proteomic data that identified several high-confidence candidate interaction proteins of UGT1A_i2 proteins in human tissues-namely, the rate-limiting enzyme of glycolysis pyruvate kinase (PKM), which plays a critical role in cancer cell metabolism and tumor growth. The partnership of UGT1A_i2 and PKM2 was confirmed by coimmunoprecipitation in the HT115 colon cancer cells and was supported by a partial colocalization of these two proteins. In support of a functional role for this partnership, depletion of UGT1A_i2 proteins in HT115 cells enforced the Warburg effect, with a higher glycolytic rate at the expense of mitochondrial respiration, and led to lactate accumulation. Untargeted metabolomics further revealed a significantly altered cellular content of 58 metabolites, including many intermediates derived from the glycolysis and tricarboxylic acid cycle pathways. These metabolic changes were associated with a greater migration potential. The potential relevance of our observations is supported by the down-regulation of UGT1A_i2 mRNA in colon tumors compared with normal tissues. Alternate UGT1A variants may thus be part of the expanding compendium of metabolic pathways involved in cancer biology directly contributing to the oncogenic phenotype of colon cancer cells. Findings uncover new aspects of UGT functions diverging from their transferase activity.
authors.affiliation: Pharmacogenomics Laboratory, Centre Hospitalier Universitaire de Québec Research Center and Faculty of Pharmacy (Y.A.-D., Mi.R., Me.R., J.R., C.G.), Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec (S.M., F.P.), and Centre Hospitalier Universitaire de Québec Research Center and Faculty of Medicine (B.T.), Laval University, Québec, Canada.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Audet-Delage
authors.affiliation: Pharmacogenomics Laboratory, Centre Hospitalier Universitaire de Québec Research Center and Faculty of Pharmacy (Y.A.-D., Mi.R., Me.R., J.R., C.G.), Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec (S.M., F.P.), and Centre Hospitalier Universitaire de Québec Research Center and Faculty of Medicine (B.T.), Laval University, Québec, Canada.
authors.forename: Michèle
authors.initials: M
authors.lastname: Rouleau
authors.affiliation: Pharmacogenomics Laboratory, Centre Hospitalier Universitaire de Québec Research Center and Faculty of Pharmacy (Y.A.-D., Mi.R., Me.R., J.R., C.G.), Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec (S.M., F.P.), and Centre Hospitalier Universitaire de Québec Research Center and Faculty of Medicine (B.T.), Laval University, Québec, Canada.
authors.forename: Mélanie
authors.initials: M
authors.lastname: Rouleau
authors.affiliation: Pharmacogenomics Laboratory, Centre Hospitalier Universitaire de Québec Research Center and Faculty of Pharmacy (Y.A.-D., Mi.R., Me.R., J.R., C.G.), Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec (S.M., F.P.), and Centre Hospitalier Universitaire de Québec Research Center and Faculty of Medicine (B.T.), Laval University, Québec, Canada.
authors.forename: Joannie
authors.initials: J
authors.lastname: Roberge
authors.affiliation: Pharmacogenomics Laboratory, Centre Hospitalier Universitaire de Québec Research Center and Faculty of Pharmacy (Y.A.-D., Mi.R., Me.R., J.R., C.G.), Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec (S.M., F.P.), and Centre Hospitalier Universitaire de Québec Research Center and Faculty of Medicine (B.T.), Laval University, Québec, Canada.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Miard
authors.affiliation: Pharmacogenomics Laboratory, Centre Hospitalier Universitaire de Québec Research Center and Faculty of Pharmacy (Y.A.-D., Mi.R., Me.R., J.R., C.G.), Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec (S.M., F.P.), and Centre Hospitalier Universitaire de Québec Research Center and Faculty of Medicine (B.T.), Laval University, Québec, Canada.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Picard
authors.affiliation: Pharmacogenomics Laboratory, Centre Hospitalier Universitaire de Québec Research Center and Faculty of Pharmacy (Y.A.-D., Mi.R., Me.R., J.R., C.G.), Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec (S.M., F.P.), and Centre Hospitalier Universitaire de Québec Research Center and Faculty of Medicine (B.T.), Laval University, Québec, Canada.
authors.forename: Bernard
authors.initials: B
authors.lastname: Têtu
authors.affiliation: Pharmacogenomics Laboratory, Centre Hospitalier Universitaire de Québec Research Center and Faculty of Pharmacy (Y.A.-D., Mi.R., Me.R., J.R., C.G.), Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec (S.M., F.P.), and Centre Hospitalier Universitaire de Québec Research Center and Faculty of Medicine (B.T.), Laval University, Québec, Canada chantal.guillemette@crchudequebec.ulaval.ca.
authors.forename: Chantal
authors.initials: C
authors.lastname: Guillemette
mesh_terms: D017398:Alternative Splicing / Q000235:genetics*; D002352:Carrier Proteins / Q000378:metabolism; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D019069:Cell Respiration; D002470:Cell Survival; D003110:Colonic Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D004734:Energy Metabolism; D015972:Gene Expression Regulation, Neoplastic; D014453:Glucuronosyltransferase / Q000235:genetics* / Q000378:metabolism; D006019:Glycolysis; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D055432:Metabolomics; D008928:Mitochondria / Q000378:metabolism; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013963:Thyroid Hormones / Q000378:metabolism; D000097810:Thyroid Hormone-Binding Proteins; D000099148:UGT1A1 Enzyme
chemical_list: D002352:Carrier Proteins; D014453:Glucuronosyltransferase; D007527:Isoenzymes; D019344:Lactic Acid; D008565:Membrane Proteins; D012333:RNA, Messenger; D013963:Thyroid Hormones; D000097810:Thyroid Hormone-Binding Proteins; D000099148:UGT1A1 Enzyme