Characterization of Numb expression in astrocytomas.
During early neurodevelopment, asymmetric segregation of Numb in mitotic progenitor cells influences the fate of daughter cells, whereby one daughter retains the progenitor phenotype while the other proceeds along a differentiation pathway. Numb has also been reported to function as a tumor suppressor in breast cancers and medulloblastomas. Given its role in maintaining neural progenitor pools in animal models and its reported role as a tumor suppressor, Numb could potentially contribute to astrocytoma oncogenesis. We characterized Numb expression in both human astrocytoma tissue samples and glioblastoma cell lines. We found that Numb is expressed in all grades of astrocytomas, being predominantly cytoplasmic in higher-grade astrocytomas but nuclear in pilocytic astrocytomas. Numb is also present in normal neurons, but not in normal astrocytes. In cultured glioblastoma cells, Numb concentrates in the perinuclear region and process tips. Numb expression in astrocytomas recapitulates that of progenitor cells during neurodevelopment, and suggests a role for Numb in astrocytoma oncogenesis.
Yan
Benedict
B
Department of Pathology, National University Hospital, Singapore.
Omar
Feroz Mohd
FM
Das
Kakoli
K
Ng
Wai Hoe
WH
Lim
Chinghway
C
Shiuan
Koh
K
Yap
Celestial T
CT
Salto-Tellez
Manuel
M
D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000378:metabolism*; D001932:Brain Neoplasms / Q000378:metabolism*; D045744:Cell Line, Tumor; D002648:Child; D002675:Child, Preschool; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000096:biosynthesis; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis*; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000096:biosynthesis*; D009457:Neuroglia / Q000378:metabolism; D009474:Neurons / Q000378:metabolism
D005904:Glial Fibrillary Acidic Protein; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C113026:NUMB protein, human