Related Experiment Video
Updated: Apr 23, 2026
Author Spotlight: Innovative Cancer Therapies with Iron Oxide Nanoparticles for Glioblastoma Treatment
Published on: September 27, 2024
Mir-34a mimics are potential therapeutic agents for p53-mutated and chemo-resistant brain tumour cells
Yuen Ngan Fan1, Daniel Meley2, Barry Pizer3
1University of Liverpool, Department of Biochemistry, Centre for Cell Imaging, Liverpool, United Kingdom.
Abstract:
Chemotherapeutic drug resistance and relapse remains a major challenge for paediatric (medulloblastoma) and adult (glioblastoma) brain tumour treatment. Medulloblastoma tumours and cell lines with mutations in the p53 signalling pathway have been shown to be specifically insensitive to DNA damaging agents. The aim of this study was to investigate the potential of triggering cell death in p53 mutated medulloblastoma cells by a direct activation of pro-death signalling downstream of p53 activation. Since non-coding microRNAs (miRNAs) have the ability to fine tune the expression of a variety of target genes, orchestrating multiple downstream effects, we hypothesised that triggering the expression of a p53 target miRNA could induce cell death in chemo-resistant cells. Treatment with etoposide, increased miR-34a levels in a p53-dependent fashion and the level of miR-34a transcription was correlated with the cell sensitivity to etoposide. miR-34a activity was validated by measuring the expression levels of one of its well described target: the NADH dependent sirtuin1 (SIRT1). Whilst drugs directly targeting SIRT1, were potent to trigger cell death at high concentrations only, introduction of synthetic miR-34a mimics was able to induce cell death in p53 mutated medulloblastoma and glioblastoma cell lines. Our results show that the need of a functional p53 signaling pathway can be bypassed by direct activation of miR-34a in brain tumour cells.
Insights
Chemo-resistant brain tumors like medulloblastoma and glioblastoma can be targeted by activating microRNA-34a (miR-34a). This bypasses the need for a functional p53 pathway, offering a new therapeutic strategy.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Chemotherapy resistance and tumor relapse are significant challenges in treating pediatric medulloblastoma and adult glioblastoma.
- Mutations in the p53 signaling pathway confer resistance to DNA-damaging agents in these brain tumors.
Purpose of the Study:
- To investigate triggering cell death in p53-mutated brain tumor cells via direct activation of pro-death signaling downstream of p53.
- To explore the potential of microRNAs (miRNAs) as therapeutic agents by targeting p53-mutated brain tumors.
Main Methods:
- Investigated the role of miR-34a, a p53 target miRNA, in inducing cell death in chemo-resistant medulloblastoma and glioblastoma cell lines.
- Administered etoposide to assess its effect on miR-34a levels and correlated miR-34a transcription with drug sensitivity.
- Validated miR-34a activity by measuring the expression of its target, SIRT1 (sirtuin1).
- Introduced synthetic miR-34a mimics to evaluate their efficacy in inducing cell death.
Main Results:
- Etoposide treatment increased miR-34a levels in a p53-dependent manner, correlating with cellular sensitivity.
- miR-34a activity was confirmed by decreased expression of its target, SIRT1.
- Synthetic miR-34a mimics effectively induced cell death in p53-mutated medulloblastoma and glioblastoma cells, unlike direct SIRT1 inhibitors.
Conclusions:
- Direct activation of miR-34a can bypass the requirement for a functional p53 signaling pathway in brain tumor cells.
- miR-34a represents a promising therapeutic strategy for overcoming chemo-resistance in p53-mutated medulloblastoma and glioblastoma.
