Our current laboratory research
Biomarker/functional studies on mitochondrial genetic variations in human cancers
Mitochondria play important roles in the development and progression of human cancers, and numerous mitochondrial DNA (mtDNA) variations have been identified in tumour cells. Those mtDNA variations may affect mitochondrial functions and interfere with cell biology via different signal transduction pathways.
In collaboration with research groups led by Professor Diana Eccles (Southampton University) and Professor Geoff Pilkington, we are currently investigating the potential of using specific mtDNA variations as effective diagnostic / prognostic biomarkers for patients with breast cancer. We are also interested in identifying mtDNA mutations that may have certain impact on the response of tumour cells to mitochondria-targeting agents, as part of our study on mitochondrially mediated apoptosis in novel therapeutics.
Parallel to the biomarker studies, we are also characterising the functional parameters of a set of selected mtDNA variations in cancer cells, based on the functional significance predicted by a 3D structural analysis tool. Using cybrids that contain mutant mitochondria and a normal nucleus as a research tool, we are able to investigate the biological behaviours of those cells and monitor the transformation progress. This study would provide a better understanding of the underlying mechanisms that initiate and/or promote tumour development and progression in cells carrying specific mtDNA abnormalities. Through collaborations within the IBBS (Professor Geoff Pilkington, Dr Helen Fillmore, Dr Rhiannon McGeehan and Dr John McGeehan) and with the Southampton team, the functional studies currently focus on glioma, breast cancer and breast brain metastasis.
Application of a 3d 'all-human' blood-brain barrier model for evaluating nanoparticle-facilitated drug delivery systems
The prognosis for patients with malignant brain tumours, in particular glioblastoma multiforme (GBM), remains very poor despite the current advances in therapy. One major hurdle of successful brain tumour therapy is the presence of the blood–brain barrier (B-BB) which precludes access for all but lipid-soluble or low molecular weight/small molecule therapeutic agents to the brain. One of the possibilities of bypassing the B-BB is to utilise specific nanoparticles (NPs) designed to interact with B-BB-forming cells at the molecular level, resulting in the transport of drugs across the B-BB without interfering with the normal function of the brain. We have previously developed and are currently validating a 3-dimensional “all-human” in vitro model of the human B-BB. This study aims to use this model to evaluate the efficacy of NP-mediated drug delivery systems. A range of novel NPs as efficient drug carriers are being formulated and tested, e.g. alkylglyceryl-modified biocompatible polymers (P-OX). Potentially this NP-based approach could also be employed to deliver therapeutic agents for a wide range of neurological diseases and disorders.
This is a collaborative project with Professor Geoff Pilkington, Dr Helen Fillmore and Dr Eugen Barbu.
Investigating the role of GAS6/AXL pathway in glioblastoma multiforme (GBM)
Axl is one of the three receptor tyrosine kinases (RTKs) in the TAM family (Tyro3, Axl, Mer). RTKs are a large family of transmembrane proteins responsible for the transduction of extracellular signals during cell growth and differentiation. Gas6 is the biological ligand for Axl and Gas6-Axl binding causes tyrosine phosphorylation of Axl which consequently activates several downstream signal transduction pathways involved in cell proliferation, survival, migration and invasion. Recent studies have suggested that the Gas6/Axl pathway may play an important role in brain tumour progression, as high levels of Gas6/Axl expression in patients with glioblastoma multiforme (GBM) correlated with poor overall survival. Using specific inhibitors and targeted shRNA knockdown to inactivate Axl, this collaborative project (with Dr Sassan Hafizi and Professor Geoff Pilkington) aims to investigate the possible roles of the Gas6/Axl signal pathway in GBM cell proliferation, migration, invasion and survival. In this study we also plan to investigate the synergistic effect of Axl inhibitor in combination with other therapeutic agents, i.e. temozolomide and tricyclics. Another objective of this study is to investigate possible connections between the Gas6/Axl pathway and mitochondria, with a view to identifying novel targets for the development of anti-cancer therapy.
Exploiting a microfluidic system as a powerful research tool
The importance of cell line authentication has been well recognised by the research community as hundreds of cell lines have been revealed as cross-contaminated or misidentified, causing numerous research data invalidated and large sums of money wasted. In light of this, more and more scientific journals have made a cell line validation statement a prerequisite for publication. At present the internationally accepted technology for cell line ID check is short tandem repeat PCR (STR-PCR) -based DNA genotyping and the standard method for analysing STR fragments, i.e. fragment length analysis (FLA), is capillary electrophoresis. Capillary electrophoresis requires sophisticated facilities and specialists to analyse the samples and interpret the data, which often results in outsourcing of this service for many research laboratories. This is time-consuming and can be expensive. We have recently developed and validated an efficient alternative for FLA by using a microfluidic electrophoresis system. This new method has proved to be more straightforward and cost-effective compared with the standard method (i.e. capillary electrophoresis).
Through collaboration with Dr Helen Fillmore, we intend to set up the authentication test at Portsmouth as a service and utilise this system as a research tool to address a broader range of scientific questions, such as genetic instability of cancer cells, genetic modification caused by in vitro cell culture, development of personalised medicine among many others.