Background
Glioblastoma is a treatment resistant, incurable primary brain tumour associated with poor survival. It has an infiltrative phenotype that precludes curative resection and is driven by a subpopulation of cancer cells with stem-like features which exhibit upregulated and activated DNA repair pathways and consequent therapy resistance. Novel therapies are urgently required.
The surrounding normal tissue of the central nervous system has unique mechanical properties, being ‘ultrasoft’ in comparison to other tissues, whilst the stiffness of glioblastoma tumours is highly heterogenous and has been correlated with transcriptomic classification and IDH-1 mutational status (Miroshnikova et al. Nat Cell Biol 2018). The mechanical properties of extracellular matrix in glioblastomas and other tumours are thought to exert a profound influence on tumour invasion and other phenotypic behaviours but is relatively understudied. Increasing stiffness of tumour related extracellular matrix has been associated with activation of DNA damage response and resistance to DNA damaging agents in other cancers (Deng et al. Sci Adv 2020). Activated DNA damage response is particularly important in determining the radiation resistance of glioblastoma stem like cells, which have an important role in causing tumour recurrence. Nevertheless, this aspect of glioblastoma behaviour is currently overlooked in available in vitro models, and the underlying mechanisms remain poorly characterised.
Our preliminary interrogation of TCGA data has shown that high expression of genes associated with increased tumour stiffness confers worse patient outcome in glioblastoma. An understanding of the interplay between extracellular matrix stiffness, DNA damage response and radiation resistance would have clear translational implications for glioblastoma patients and could result in tailored precision medicine approaches for tumours exhibiting differing transcriptomic signatures of extracellular matrix stiffness. This project will seek to understand the role of tumour stiffness in determining radiation response in glioblastoma and investigate the efficacy of DNA damage response inhibition in tumours exhibiting differing extracellular matrix stiffness.
Aims
1) Optimise an in vitro culture system to investigate the effect of matrix mechanics on glioblastoma biology and treatment response. Adapt hydrogels of tuneable stiffness for 2D and 3D culture of primary glioblastoma cell lines by incorporation of brain-relevant matrix proteins and growth factors. Quantify basal DNA damage levels and investigate DNA damage response activation in primary glioblastoma cell lines cultured on substrates of differing stiffness.
2) Investigate the effect of extracellular stiffness on radiation sensitivity and invasion in primary glioblastoma cell lines. Characterise the effects of inhibition of clinically targetable DNA damage response proteins (ATM, ATR and PARP) on radiation sensitivity of glioblastoma cell cultures on substrates of differing stiffness.
3) Interrogate transcriptomic changes in primary cells cultured in substrates of differing stiffness in order to refine transcriptomic signatures of extracellular matrix stiffness to identify tumours which may show altered sensitifvity to radiation or DNA damage response inhibition. Identified signatures will be further tested in existing and novel clinical datasets (TCGA, CGGA, PARADIGM clinical trials (Chalmers CI)).
Training outcomes
1) Competence in advanced cell culture techniques and optimisation of novel extracellular matrix models in vitro.
2) Proficiency in in vitro interrogation of cell survival (clonogenic/cell viability assays) and DNA damage responses (immunofluorescence of DNA repair foci, cell cycle checkpoint assays, immunoblotting).
3) Familiarity with preparation of samples for RNAseq. Analysis of RNAseq and development of transcriptomic signatures. Interrogation of clinical datasets and correlation of signatures with clinical outcome data.
Application Instructions:
This MRC programme is joint between the Universities of Edinburgh and Glasgow. You will be registered at the host institution of the primary supervisor detailed in your project selection.
All applications should be made via the University of Edinburgh, irrespective of project location. For those applying to a University of Glasgow project, your application along with any supporting documents will be shared with University of Glasgow.
http://www.ed.ac.uk/studying/postgraduate/degrees/index.php?r=site/view&id=919
Please note, you must apply to one of the projects and you must contact the primary supervisor prior to making your application. Additional information on the application process is available from the link above.
For more information about Precision Medicine visit:
http://www.ed.ac.uk/usher/precision-medicine
Application Enquiries:
Susan Mitchell/Maree Hardie
[Email Address Removed]
https://www.ed.ac.uk/usher/precision-medicine/app-process-eligibility-criteria