Associação Portuguesa de Investigação em Cancro
Probing the O-glycoproteome of Gastric Cancer Cell Lines for Biomarker Discovery
Probing the O-glycoproteome of Gastric Cancer Cell Lines for Biomarker Discovery
Este trabalho realizado em colaboração por várias instituições de investigação (IPATIMUP, IPO-Porto, Faculdade de Medicina e ICBAS da Universidade do Porto, Universidade de Aveiro, e Universidade de Copenhaga), e publicado na Molecular & Cellular Proteomics, caracterizou o O-glicoproteoma de células gástricas geneticamente modificadas com o objetivo de identificar potenciais biomarcadores específicos do carcinoma gástrico. O estudo permitiu ainda a identificação de glicoformas aberrantes expressas em proteínas em circulação no soro de doentes com carcinomas gástricos. Estas glicoformas aberrantes (O-glicanos truncados) são produzidas por carcinomas, mas não por células normais, constituindo potenciais biomarcadores detetáveis no soro dos doentes.
Autores e Afiliações:
Diana Campos1,2, Daniela Freitas2, Joana Gomes2, Ana Magalhães2, Catharina Steentoft1, Catarina Gomes2, Malene B. Vester-Christensen1*, José Alexandre Ferreira3,4, Luis P. Afonso5, Lúcio L. Santos3, João Pinto de Sousa6, Ulla Mandel1, Henrik Clausen1, Sergey Y. Vakhrushev1, Celso A. Reis2,6,7
1 Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine and School of Dentistry, Faculty of Health Sciences, University of Copenhagen
2 IPATIMUP, Institute of Molecular Pathology and Immunology of the University of Porto
3 Experimental Pathology and Therapeutics Group, Portuguese Institute of Oncology
4 QOPNA, Department of Chemistry of the University of Aveiro
5 Department of Pathology, Portuguese Institute of Oncology
6 Faculty of Medicine of the University of Porto
7 Institute of Biomedical Sciences Abel Salazar, ICBAS
Abstract:
Circulating O-glycoproteins shed from cancer cells represent important serum biomarkers for diagnostic and prognostic purposes. We have recently shown that selective detection of cancer-associated aberrant glycoforms of circulating O-glycoprotein biomarkers can increase specificity of cancer biomarker assays. However, the current knowledge of secreted and circulating O-glycoproteins is limited. Here, we used the COSMC KO "SimpleCell" (SC) strategy to characterize the O-glycoproteome of two gastric cancer SC lines (AGS, MKN45) as well as a gastric cell line (KATO III) which naturally expresses at least partially truncated O-glycans. Overall we identified 499 O-glycoproteins and 1,236 O-glycosites in gastric cancer SCs, and a total 47 O-glycoproteins and 73 O-glycosites in the KATO III cell line. We next modified the glycoproteomic strategy to apply it to pools of sera from gastric cancer and healthy individuals to identify circulating O-glycoproteins with the STn glycoform. We identified 37 O-glycoproteins in the pool of cancer sera, and only 9 of these were also found in sera from healthy individuals. Two identified candidate O-glycoprotein biomarkers (CD44 and GalNAc-T5) circulating with the STn glycoform were further validated as being expressed in gastric cancer tissue. A proximity ligation assay was used to demonstrate that CD44 was expressed with the STn glycoform in gastric cancer tissues. The study provides a discovery strategy for aberrantly glycosylated O-glycoproteins and a set of O-glycoprotein candidates with biomarker potential in gastric cancer.
Revista: Molecular & Cellular Proteomics
