title: Biochemical signatures of doppel protein in human astrocytomas to support prediction in tumor malignancy.
abstract: Doppel (Dpl) is a membrane-bound glycoprotein mainly expressed in the testis of adult healthy people. It is generally absent in the central nervous system, but its coding gene sequence is ectopically expressed in astrocytoma specimens and in derived cell lines. In this paper, we investigated the expression and the biochemical features of Dpl in a panel of 49 astrocytoma specimens of different WHO malignancy grades. As a result, Dpl was expressed in the majority of the investigated specimens (86%), also including low grade samples. Importantly, Dpl exhibited different cellular localizations and altered glycan moieties composition, depending on the tumor grade. Most low-grade astrocytomas (83%) showed a membrane-bound Dpl, like human healthy testis tissue, whereas the majority of high-grade astrocytomas (75%) displayed a cytosolic Dpl. Deglycosylation studies with N-glycosidase F and/or neuraminidase highlighted defective glycan moieties and an unexpected loss of sialic acid. To find associations between glial tumor progression and Dpl biochemical features, predictive bioinformatics approaches were produced. In particular, Decision tree and Nomogram analysis showed well-defined Dpl-based criteria that separately clustered low-and high-grade astrocytomas. Taken together, these findings show that in astrocytomas, Dpl undergoes different molecular processes that might constitute additional helpful tools to characterize the glial tumor progression.
authors.affiliation: Dipartimento di Biochimica, A. Castellani, University of Pavia, Via Taramelli 3/b, 27100 Pavia, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Rognoni
authors.forename: Laurent R
authors.initials: LR
authors.lastname: Chiarelli
authors.forename: Sergio
authors.initials: S
authors.lastname: Comincini
authors.forename: Alberto
authors.initials: A
authors.lastname: Azzalin
authors.forename: Clelia
authors.initials: C
authors.lastname: Miracco
authors.forename: Giovanna
authors.initials: G
authors.lastname: Valentini
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001254:Astrocytoma / Q000378:metabolism / Q000473:pathology*; D014408:Biomarkers, Tumor; D015153:Blotting, Western; D001932:Brain Neoplasms / Q000378:metabolism / Q000473:pathology*; D002462:Cell Membrane / Q000378:metabolism; D002648:Child; D016000:Cluster Analysis; D003593:Cytoplasm / Q000378:metabolism; D018450:Disease Progression; D005260:Female; D058851:GPI-Linked Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D019158:N-Acetylneuraminic Acid / Q000378:metabolism; D011237:Predictive Value of Tests; D011328:Prions / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D058851:GPI-Linked Proteins; C501125:PRND protein, human; D011328:Prions; D019158:N-Acetylneuraminic Acid