Targeting A20 decreases glioma stem cell survival and tumor growth.
Abstract
Glioblastomas are deadly cancers that display a functional cellular hierarchy maintained
by self-renewing glioblastoma stem cells (GSCs). GSCs are regulated by molecular pathways
distinct from the bulk tumor that may be useful therapeutic targets. We determined
that A20 (TNFAIP3), a regulator of cell survival and the NF-kappaB pathway, is overexpressed
in GSCs relative to non-stem glioblastoma cells at both the mRNA and protein levels.
To determine the functional significance of A20 in GSCs, we targeted A20 expression
with lentiviral-mediated delivery of short hairpin RNA (shRNA). Inhibiting A20 expression
decreased GSC growth and survival through mechanisms associated with decreased cell-cycle
progression and decreased phosphorylation of p65/RelA. Elevated levels of A20 in GSCs
contributed to apoptotic resistance: GSCs were less susceptible to TNFalpha-induced
cell death than matched non-stem glioma cells, but A20 knockdown sensitized GSCs to
TNFalpha-mediated apoptosis. The decreased survival of GSCs upon A20 knockdown contributed
to the reduced ability of these cells to self-renew in primary and secondary neurosphere
formation assays. The tumorigenic potential of GSCs was decreased with A20 targeting,
resulting in increased survival of mice bearing human glioma xenografts. In silico
analysis of a glioma patient genomic database indicates that A20 overexpression and
amplification is inversely correlated with survival. Together these data indicate
that A20 contributes to glioma maintenance through effects on the glioma stem cell
subpopulation. Although inactivating mutations in A20 in lymphoma suggest A20 can
act as a tumor suppressor, similar point mutations have not been identified through
glioma genomic sequencing: in fact, our data suggest A20 may function as a tumor enhancer
in glioma through promotion of GSC survival. A20 anticancer therapies should therefore
be viewed with caution as effects will likely differ depending on the tumor type.
Type
Journal articleSubject
AnimalsBlotting, Western
Cell Survival
Cells, Cultured
DNA-Binding Proteins
Flow Cytometry
Fluorescent Antibody Technique
Gene Expression Regulation, Neoplastic
Glioblastoma
Humans
In Situ Nick-End Labeling
Intracellular Signaling Peptides and Proteins
Mice
Mice, Nude
Mutation
Neoplastic Stem Cells
Nuclear Proteins
Polymerase Chain Reaction
Survival Analysis
Transplantation, Heterologous
Tumor Necrosis Factor alpha-Induced Protein 3
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https://hdl.handle.net/10161/4444Published Version (Please cite this version)
10.1371/journal.pbio.1000319Publication Info
Hjelmeland, AB; Wu, Q; Wickman, S; Eyler, C; Heddleston, J; Shi, Q; ... Rich, JN (2010). Targeting A20 decreases glioma stem cell survival and tumor growth. PLoS Biol, 8(2). pp. e1000319. 10.1371/journal.pbio.1000319. Retrieved from https://hdl.handle.net/10161/4444.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Show full item recordScholars@Duke
Christine Elissa Eyler
Assistant Professor of Radiation Oncology
Roger Edwin McLendon
Professor of Pathology
Brain tumors are diagnosed in more than 20,000 Americans annually. The most malignant
neoplasm, glioblastoma, is also the most common. Similarly, brain tumors constitute
the most common solid neoplasm in children and include astrocytomas of the cerebellum,
brain stem and cerebrum as well as medulloblastomas of the cerebellum. My colleagues
and I have endeavored to translate the bench discoveries of genetic mutations and
aberrant protein expressions found in brain tumors to better understan
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