title: Altered cellular distribution and subcellular sorting of gamma-tubulin in diffuse astrocytic gliomas and human glioblastoma cell lines.
abstract: Centrosome amplification is a pivotal mechanism underlying tumorigenesis but its role in gliomas is underinvestigated. The present study specifically examines the expression and distribution of the centrosome-associated cytoskeletal protein gamma-tubulin in 56 primary diffuse astrocytic gliomas (grades II-IV) and in 4 human glioblastoma cell lines (U87MG, U118MG, U138MG, and T98G). Monoclonal anti-peptide antibodies recognizing epitopes in C-terminal or N-terminal domains of the gamma-tubulin molecule were used in immunohistochemical, immunofluorescence, and immunoblotting studies. In tumors in adults (n = 46), varying degrees of localization were detected in all tumor grades, but immunoreactivity was significantly increased in high-grade anaplastic astrocytomas and glioblastomas multiforme as compared to low-grade diffuse astrocytomas (p = 0.0001). A similar trend was noted in diffuse gliomas in children but the sample of cases was too small as to be statistically meaningful. Two overlapping patterns of ectopic cellular localization were identified in both primary tumors and glioblastoma cell lines: A punctate pattern, in which gamma-tubulin was partially co-distributed with pericentrin in the pericentriolar region, and a diffuse pattern, independent of pericentrin staining, denoting a soluble pool of gamma-tubulin. Cellular gamma-tubulin was detected in both soluble and insoluble (nocodazole-resistant) fractions of glioblastoma cells. Divergent localizations of gamma-tubulin and pericentrin suggest a differential distribution of these 2 centrosome-associated proteins in glioblastoma cell lines. Our results indicate that overexpression and ectopic cellular distribution of gamma-tubulin in astrocytic gliomas may be significant in the context of centrosome protein amplification and may be linked to tumor progression and anaplastic potential.
authors.affiliation: Department of Pediatrics, Drexel University College of Medicine, St. Christopher's Hospital for Children, Philadelphia, Pennsylvania 19134, USA. Christos.Katsetos@DrexelMed.edu
authors.forename: Christos D
authors.initials: CD
authors.lastname: Katsetos
authors.forename: Goutham
authors.initials: G
authors.lastname: Reddy
authors.forename: Eduarda
authors.initials: E
authors.lastname: Dráberová
authors.forename: Barbora
authors.initials: B
authors.lastname: Smejkalová
authors.forename: Luis
authors.initials: L
authors.lastname: Del Valle
authors.forename: Qazi
authors.initials: Q
authors.lastname: Ashraf
authors.forename: Ashot
authors.initials: A
authors.lastname: Tadevosyan
authors.forename: Karina
authors.initials: K
authors.lastname: Yelin
authors.forename: Theodoros
authors.initials: T
authors.lastname: Maraziotis
authors.forename: Om P
authors.initials: OP
authors.lastname: Mishra
authors.forename: Sverre
authors.initials: S
authors.lastname: Mörk
authors.forename: Agustin
authors.initials: A
authors.lastname: Legido
authors.forename: Jonathan
authors.initials: J
authors.lastname: Nissanov
authors.forename: Peter W
authors.initials: PW
authors.lastname: Baas
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: de Chadarévian
authors.forename: Pavel
authors.initials: P
authors.lastname: Dráber
mesh_terms: D000941:Antigens / Q000378:metabolism; D015152:Blotting, Northern / Q000379:methods; D045744:Cell Line, Tumor; D003593:Cytoplasm / Q000378:metabolism*; D005909:Glioblastoma / Q000145:classification / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D042541:Intracellular Space / Q000378:metabolism*; D014404:Tubulin / Q000378:metabolism*
chemical_list: D000941:Antigens; D014404:Tubulin; C086178:pericentrin