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Updated: Jul 21, 2026
Coculture Assays to Study Macrophage and Microglia Stimulation of Glioblastoma Invasion
Published on: October 20, 2016
Glioma invasion mediated by the p75 neurotrophin receptor (p75(NTR)/CD271) requires regulated interaction with PDLIM1
B Y Ahn1,2,3, R F G Saldanha-Gama1,3,4, J J Rahn1,2,3
1Southern Alberta Cancer Research Institute, University of Calgary, Calgary, Alberta, Canada.
Abstract:
The invasive nature of glioblastoma renders them incurable by current therapeutic interventions. Using a novel invasive human glioma model, we previously identified the neurotrophin receptor p75(NTR) (aka CD271) as a mediator of glioma invasion. Herein, we provide evidence that preventing phosphorylation of p75(NTR) on S303 by pharmacological inhibition of PKA, or by a mutational strategy (S303G), cripples p75(NTR)-mediated glioma invasion resulting in serine phosphorylation within the C-terminal PDZ-binding motif (SPV) of p75(NTR). Consistent with this, deletion (ΔSPV) or mutation (SPM) of the PDZ motif results in abrogation of p75(NTR)-mediated invasion. Using a peptide-based strategy, we identified PDLIM1 as a novel signaling adaptor for p75(NTR) and provide the first evidence for a regulated interaction via S425 phosphorylation. Importantly, PDLIM1 was shown to interact with p75(NTR) in highly invasive patient-derived glioma stem cells/tumor-initiating cells and shRNA knockdown of PDLIM1 in vitro and in vivo results in complete ablation of p75(NTR)-mediated invasion. Collectively, these data demonstrate a requirement for a regulated interaction of p75(NTR) with PDLIM1 and suggest that targeting either the PDZ domain interactions and/or the phosphorylation of p75(NTR) by PKA could provide therapeutic strategies for patients with glioblastoma.
Insights
Targeting neurotrophin receptor p75(NTR) phosphorylation or PDZ interactions can inhibit glioblastoma invasion. This study identifies PDLIM1 as a key interaction partner for p75(NTR), offering new therapeutic strategies for glioblastoma.
Area of Science:
- Neuro-oncology
- Molecular biology
- Cancer research
Background:
- Glioblastoma is an aggressive brain tumor with poor prognosis.
- The neurotrophin receptor p75(NTR) (CD271) is implicated in mediating glioma cell invasion.
- Current therapies are insufficient to overcome glioblastoma's invasive nature.
Purpose of the Study:
- To investigate the role of p75(NTR) phosphorylation and its downstream interactions in glioblastoma invasion.
- To identify novel therapeutic targets for inhibiting glioblastoma cell motility.
Main Methods:
- Utilized a novel invasive human glioma model and patient-derived glioma stem cells.
- Employed pharmacological inhibition of PKA and site-directed mutagenesis (S303G, S425D) to study p75(NTR) phosphorylation.
- Investigated PDZ motif interactions using deletion (ΔSPV) and mutation (SPM) strategies.
- Identified PDLIM1 as a p75(NTR) interacting protein using a peptide-based approach.
- Assessed the impact of PDLIM1 knockdown via shRNA in vitro and in vivo.
Main Results:
- Inhibition of p75(NTR) phosphorylation at S303 by PKA or S303G mutation significantly reduced glioma invasion.
- Disruption of the C-terminal PDZ-binding motif (SPV) of p75(NTR) abrogated invasion.
- PDLIM1 was identified as a novel signaling adaptor interacting with p75(NTR), regulated by S425 phosphorylation.
- PDLIM1 interacts with p75(NTR) in patient-derived glioma stem cells.
- Knockdown of PDLIM1 completely abolished p75(NTR)-mediated invasion both in vitro and in vivo.
Conclusions:
- A regulated interaction between p75(NTR) and PDLIM1 is crucial for glioblastoma invasion.
- Targeting p75(NTR) phosphorylation by PKA or its PDZ domain interactions presents a promising therapeutic avenue for glioblastoma.
