Investigating the differential regulation of cell surface GAG in brain cancer: Using NGPD to isolate cancer cell specific peptides

Personalised cancer medicine aims to direct therapy against the specific cell attributes in an individual's tumour, sparing side effects whilst enhancing efficacy. Most of these strategies focus on targeting the genetic abnormality, rather than the cell body itself. This approach has so far failed in several aggressive cancers owing in considerable part to intra-tumour heterogeneity with different genetic defects. This complexity results from cancers being initiated by a subpopulation of self-renewing cancer stem cells (CSC) that have superior tumorigenic and metastatic properties, are resistant to radiotherapy and chemotherapy and, therefore, responsible for tumour recurrence. Being able to isolate different tumour cell phenotypes rapidly will be an immensely important tool to understand the cell biology of CSCs and how heterogeneity in the tumour allows them to evade therapies. We have developed a novel drug delivery platform (2-orders of magnitude higher cell delivery efficiencies) termed Glycosaminoglycan-enhanced transduction (GET). This technology uses cell penetrating peptides (CPPs) coupled to heparan sulphate (HS) binding-peptides. By using specific HS targeting peptides we have shown cell-type specific targeting and as HS is misregulated on a variety of tumour cells this represents a unique strategy. HS plays roles in cell signalling, migration and tissue extracellular matrices meaning that it has great influence on cell behaviour. For brain cancers there is intensive effort to discover novel biomarkers for more sophisticated diagnosis and treatment methods. In this project, we propose to identify cell-type specific variants in glioblastoma patient samples in a high-throughput manner using phage display-libraries (1010 phage) of GET peptides and next-generation sequencing (NGS) in a process called next generation phage display (NGPD). Sequences are retrieved from internalised phage and by comparing with control cells it is possible to identify high-efficiency targeting peptides. This will be done in collaboration with Dr Kevin Gough who has developed the NGPD technology and will be informed by Cancer Biologists Dr. Cinzia Allegrucci (SVMS) and Dr. Ruman Rahman (CBTRC). Peptides isolated will be used to assess the cell phenotype and as markers to aid research in to the cell biology of heterogeneous tumours.