title: Hypoxia enhances the malignant nature of bladder cancer cells and concomitantly antagonizes protein O-glycosylation extension.
abstract: Invasive bladder tumours express the cell-surface Sialyl-Tn (STn) antigen, which stems from a premature stop in protein O-glycosylation. The STn antigen favours invasion, immune escape, and possibly chemotherapy resistance, making it attractive for target therapeutics. However, the events leading to such deregulation in protein glycosylation are mostly unknown. Since hypoxia is a salient feature of advanced stage tumours, we searched into how it influences bladder cancer cells glycophenotype, with emphasis on STn expression. Therefore, three bladder cancer cell lines with distinct genetic and molecular backgrounds (T24, 5637 and HT1376) were submitted to hypoxia. To disclose HIF-1α-mediated events, experiments were also conducted in the presence of Deferoxamine Mesilate (Dfx), an inhibitor of HIF-1α proteasomal degradation. In both conditions all cell lines overexpressed HIF-1α and its transcriptionally-regulated protein CA-IX. This was accompanied by increased lactate biosynthesis, denoting a shift toward anaerobic metabolism. Concomitantly, T24 and 5637 cells acquired a more motile phenotype, consistent with their more mesenchymal characteristics. Moreover, hypoxia promoted STn antigen overexpression in all cell lines and enhanced the migration and invasion of those presenting more mesenchymal characteristics, in an HIF-1α-dependent manner. These effects were reversed by reoxygenation, demonstrating that oxygen affects O-glycan extension. Glycoproteomics studies highlighted that STn was mainly present in integrins and cadherins, suggesting a possible role for this glycan in adhesion, cell motility and invasion. The association between HIF-1α and STn overexpressions and tumour invasion was further confirmed in bladder cancer patient samples. In conclusion, STn overexpression may, in part, result from a HIF-1α mediated cell-survival strategy to adapt to the hypoxic challenge, favouring cell invasion. In addition, targeting STn-expressing glycoproteins may offer potential to treat tumour hypoxic niches harbouring more malignant cells.
authors.affiliation: Experimental Pathology and Therapeutics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.|New Therapies Group, INEB-Institute for Biomedical Engineering, Porto, Portugal.|Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.|Institute of Biomedical Sciences Abel Salazar, University of Porto, Porto, Portugal.
authors.forename: Andreia
authors.initials: A
authors.lastname: Peixoto
authors.affiliation: Experimental Pathology and Therapeutics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.|Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.|Institute of Biomedical Sciences Abel Salazar, University of Porto, Porto, Portugal.|Biomaterials for Multistage Drug and Cell Delivery, INEB-Institute for Biomedical Engineering, Porto, Portugal.
authors.forename: Elisabete
authors.initials: E
authors.lastname: Fernandes
authors.affiliation: Experimental Pathology and Therapeutics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.
authors.forename: Cristiana
authors.initials: C
authors.lastname: Gaiteiro
authors.affiliation: Experimental Pathology and Therapeutics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.|Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.|Glycobiology in Cancer, Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal.
authors.forename: Luís
authors.initials: L
authors.lastname: Lima
authors.affiliation: Experimental Pathology and Therapeutics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.|Institute of Biomedical Sciences Abel Salazar, University of Porto, Porto, Portugal.
authors.forename: Rita
authors.initials: R
authors.lastname: Azevedo
authors.affiliation: Experimental Pathology and Therapeutics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.
authors.forename: Janine
authors.initials: J
authors.lastname: Soares
authors.affiliation: Experimental Pathology and Therapeutics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.
authors.forename: Sofia
authors.initials: S
authors.lastname: Cotton
authors.affiliation: Experimental Pathology and Therapeutics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Parreira
authors.affiliation: Experimental Pathology and Therapeutics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.|Institute of Biomedical Sciences Abel Salazar, University of Porto, Porto, Portugal.
authors.forename: Manuel
authors.initials: M
authors.lastname: Neves
authors.affiliation: Department of Pathology, Hospital Pedro Hispano, Matosinhos, Portugal.
authors.forename: Teresina
authors.initials: T
authors.lastname: Amaro
authors.affiliation: Experimental Pathology and Therapeutics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.|Department of Pathology, Hospital Pedro Hispano, Matosinhos, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Tavares
authors.affiliation: LAQV-REQUIMTE, Faculty of Sciences of the University of Porto, Porto, Portugal.
authors.forename: Filipe
authors.initials: F
authors.lastname: Teixeira
authors.affiliation: Experimental Pathology and Therapeutics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.|Health School of University Fernando Pessoa, Porto, Portugal.
authors.forename: Carlos
authors.initials: C
authors.lastname: Palmeira
authors.affiliation: UCIBIO-REQUIMTE, Instituto de Ciências Biomédicas Abel Salazar, University of Porto, Porto, Portugal.
authors.forename: Maria
authors.initials: M
authors.lastname: Rangel
authors.affiliation: UCIBIO-REQUIMTE/Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Porto, Portugal.
authors.forename: André M N
authors.initials: AM
authors.lastname: Silva
authors.affiliation: Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.|Institute of Biomedical Sciences Abel Salazar, University of Porto, Porto, Portugal.|Glycobiology in Cancer, Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal.|Department of Pathology and Oncology, Faculty of Medicine, Porto University, Porto, Portugal.
authors.forename: Celso A
authors.initials: CA
authors.lastname: Reis
authors.affiliation: Experimental Pathology and Therapeutics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.|Health School of University Fernando Pessoa, Porto, Portugal.|Department of Surgical Oncology, Portuguese Institute of Oncology, Porto, Portugal.
authors.forename: Lúcio Lara
authors.initials: LL
authors.lastname: Santos
authors.affiliation: New Therapies Group, INEB-Institute for Biomedical Engineering, Porto, Portugal.|Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.
authors.forename: Maria José
authors.initials: MJ
authors.lastname: Oliveira
authors.affiliation: Experimental Pathology and Therapeutics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.|Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.|Institute of Biomedical Sciences Abel Salazar, University of Porto, Porto, Portugal.|Glycobiology in Cancer, Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal.|Porto Comprehensive Cancer Center (P.ccc), Porto, Portugal.
authors.forename: José Alexandre
authors.initials: JA
authors.lastname: Ferreira
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000378:metabolism; D000951:Antigens, Neoplasm / Q000378:metabolism; D000071231:Carbonic Anhydrase IX / Q000378:metabolism; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D002465:Cell Movement; D003676:Deferoxamine / Q000737:chemistry; D005260:Female; D006023:Glycoproteins / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D019344:Lactic Acid / Q000737:chemistry; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D010641:Phenotype; D011134:Polysaccharides / Q000737:chemistry; D040901:Proteomics; D012799:Sialyltransferases / Q000378:metabolism; D001749:Urinary Bladder Neoplasms / Q000378:metabolism / Q000473:pathology*; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase
chemical_list: D015703:Antigens, CD; D000951:Antigens, Neoplasm; D000071231:Carbonic Anhydrase IX; D003676:Deferoxamine; D006023:Glycoproteins; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D019344:Lactic Acid; D011134:Polysaccharides; D012799:Sialyltransferases; C497442:HIF1A protein, human; C093493:ST6GAL1 protein, human; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase; C089226:CA9 protein, human
keywords: bladder cancer; glycosylation; hypoxia; invasion; sialyl-Tn