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Project 1: Does the tissue micro-environment contribute to radiotherapy resistance in breast cancer?
Supervisors: Professor Elinor Sawyer, Professor Anita Grigoriadis
Radiotherapy is routinely used in the treatment of breast cancer to reduce the risk of local recurrence and improve survival.
However, despite radiotherapy some patients still experience recurrences, and this is associated with worse long-term outcomes.
If biomarkers of radiation resistance could be identified there would be considerable clinical utility as it could accurately identify who would benefit from increased doses of radiation or more extensive surgery. It would also allow the development of more novel approaches such as combining radiotherapy with radiosensitizers.
Our preliminary data suggests that the tumour microenvironment rather than just the intrinsic features of the cancer cells contribute to radiation resistance in breast cancer.
The aims of this project are to answer the following questions:
1. Is the tumour microenvironment important in radio-resistance of breast cancer?
2. Do tumour microenvironment radio-resistance pathways differ in different subtypes of breast cancer?
3. Can radiotherapy change the tumour microenvironment making it more pro-tumourigenic?
This research proposal will focus on the analysis of the tumour microenvironment in three independent samples sets.
We will use the spatial profiling techniques to assess the expression of genes in the immune, stromal and tumour compartments in a set of 100 samples from each of the datasets, 50 who developed a recurrence despite radiotherapy (radioresistant group) and 50 that received radiotherapy and did not recur after 9 years follow up (radiosensitive group).
Tissue microarrays are already available for one of the datasets and are currently undergoing spatial profiling. The data will be available for analysis by the time of the start of the PhD. Based on these preliminary results the candidate will ascertain the best spatial platform for the analysis of the remainder of the samples. The group of Professor Grigoriadis (second supervisor) runs the KCL spatial facility and analysis pipelines are established.
The paired subsequent ipsilateral recurrences are also available for analysis enabling us to study the changes that are induced in the TME following radiation. There is some evidence that radiotherapy can induce cancer ECM remodelling, leading to an environment that may encourage tumour recurrence.
Project 2: Dissecting the role of the microbiome in the radiotherapy response of glioblastoma multiforme to develop novel combination therapies
Supervisors: Dr Miguel Reis Ferreira, Dr Lindsey Edwards, Dr Leone Rossetti
The term "human microbiome” is used to describe a community of tightly associated micro-organisms, including bacteria, fungi, viruses and protozoa, which are in intimate contact and continually interact with human tissues. Bacteria modulate the development, progression and treatment response of cancers. These effects may be modulated locally, through bacteria in close contact with tissues, termed bacterial biofilms, or through bacteria-to-human signalling mediators secreted by the gut microbiota, which then modulate host immunity and/or promote cancer development and treatment response in sites distant to the gut. The existence of intra-tumoural bacteria in gliomas is suggested in several studies but still controversial. If existent, these bacteria may contribute to radiotherapy efficacy as documented by MRF and his team in head and neck cancers.
We recently identified that antibiotic exposure during treatment for glioblastoma multiforme (GBM) significantly reduced survival in univariate and multivariate analyses in a cohort of 234 patients treated at a major tertiary centre in the UK (presented internationally, publication under peer review). This effect was most pronounced in patients with the better prognosis. Results were externally validated of 141 patients.
These results suggest that changes in bacterial communities either within tumours or in the gut lead to an increase in HGG resistance to treatment. Such changes may be mitigated by interventions that recover the microbiome after antibiotics, such as faecal microbiome transplants (FMT).
The hypothesis underpinning the project is that bacteria or their metabolic products mechanistically impact GBM radioresistance. Subsidiary hypotheses are that intra-tumoural bacteria exist in HGG and contribute to radiotherapy responses; that antibiotics during treatment impact the gut microbiota causing radioresistance via metabolic or immune modulation. To test these hypotheses, a translational study will be conducted.
Firstly, a cross-sectional exploratory study of the intra-tumoural microbiome in HGG will be conducted in 20 patients (Microbiome in High-Grade Glioma, Mi-HGG, IRAS 334454). This study is already funded, approved and has been included in the NIHR-CRN portfolio. Sequencing, FISH and culture techniques will detect intra-tumoural bacteria. Metagenomic sequencing will characterise the faecal microbiome and stool aliquotes will be stored. Further samples will be taken after any broad-spectrum antibiotic course.
Secondly, using mouse models of glioma (e.g., GL261) and leveraging the KCL/CoL preclinical irradiation facility, we will use faecal microbiota transplantation (FMT) of stools from GBM patients to compare the response to radio-chemotherapy between groups receiving FMT from donors treated and not treated with antibiotics. After sacrifice, tumours will be assessed for size, tumour death, presence of bacteria and immune infiltration. This approach will define the causality of the gut and potentially tumour-associated microbiome in modulating GBM radioresistance.
Finally, using 2D and 3D models of GBM and optogenetic generation of cell migration,[5] the direct effects of bacteria and/or their metabolites (faecal water extraction) on the mechanical properties of GBM cells before and after irradiation in clinically-active linear accelerators at Guys (pathway established by MRF) will be evaluated, including cell stiffness, extracellular matrix adherence, contractility and movement, providing an indication as to whether bacteria or their metabolites modulate GBM invasiveness after irradiation.
Project 3: Development of a cancer universal match paired theranostic/molecular radiotherapy
Supervisors: Dr Graeme Stasiuk, Dr Adam Sedgwick
Current clinical care of cancers typically relies on imaging of the tumour for diagnosis and therapeutic interventions (surgery, chemotherapy, radiotherapy) to be performed separately, sometimes several weeks apart. Critically, during this time, the tumour has the opportunity to grow and spread. In this project, we seek to combine both imaging and therapy into a match paired theranostic treatment. This has the potential to inhibit tumour growth directly following diagnosis, by using the same intervention, i.e. with different isotopic element (212Pb/203Pb) for imaging and therapy. The chosen imaging modality, positron emission tomography (PET), is regarded as the technique of choice for identifying tumours due to its high sensitivity. To enable therapy, we will use molecular radiotherapy from a beta/alpha emitting isotope. Theranostics is the combination of therapy and diagnostic imaging in one tool. Nuclear medicine has currently adopted a theranostic “matched pair” radioisotopes approach, the gold standard is with 68Ga (PET) 177Lu (therapy).There is a difference in biodistribution of the imaging tracer and the radionuclide therapy, due to the difference in coordination chemistry between 68Ga and 177Lu requiring different chelators, thus presenting issues with dosimetry, and efficacy of the treatment. In contrast this project will utilise a “true theranostic pair” in which two radionuclides of the same element are used (44/47Sc, 64/67Cu, 203/212Pb). This approach has the advantage of providing the exact same biodistribution between the imaging and therapy to ensure accurate diagnosis, dosimetry, and monitoring of disease progression.
The MRT will be targeted to Fibroblast Activation Protein Inhibitor (FAPI), targeting the FAP, which is known to be highly expressed in the major cell population in tumor stroma, termed cancer-associated fibroblasts. We will study this MRT in Breast cancer (BC) a model cancer: approximately 55,500 patients are diagnosed per annum in UK with BC and 1 in 7 women in the UK develop BC in their lifetime. A novel adjuvant therapeutic tools are therefore needed to tackle BC.
To investigate this hypothesis, the multidisciplinary project will involve chemical synthesis of novel chelators that will incorporate the radiometal (44/47Sc, 64/67Cu, 203/212Pb), followed by bioconjugation to a FAPI targeting motif. This work will draw on feasibility studies from our team. This will be followed by radiolabelling experiments to show specific uptake into the chelator, radiochemical yield and specific activity. Once the theranostic/MRT agent has been made, it will be validated in FAP overexpressing breast cancer lines along with control tumour cell lines to demonstrate specific uptake in overexpressing cells and toxicity/radiobiological effect of the MRT. This will be followed by in vivo experiments to show the efficacy of the therapeutic in preclinical tumour models.
The project is suitable for a student with background in organic chemistry and a strong interest in life sciences, in particular oncology. The student will be able to gain new interdisciplinary skills such as radiochemistry, cell culture, in vivo preclinical imaging, and acquire expert knowledge in basic medical science research.
Project 4: SMART: Small Molecule Activatable RadioTherapeutics
Supervisors: Dr Adam Sedgwick, Dr Samantha Terry
Chemoradiotherapy (chemotherapy + radiotherapy) is a crucial first-line treatment, where a patient receives a chemotherapeutic in combination with radiotherapy. Although effective, the narrow therapeutic window and high systemic toxicity of currently used chemotherapy means not every patient can tolerate this combination therapy, and the resulting dose-limiting toxicities impacts treatment success rates. This project will exploit the high-energy radiation generated from radiotherapy or radiopharmaceuticals to locally activate non-toxic prodrugs to afford the corresponding cytotoxic drugs. The aim of this project is to address the systemic toxicity challenges seen for currently approved anticancer agents in chemoradiotherapy whilst maximising use of radiotherapy regimens.
Prodrugs are “masked” chemotherapeutics with potential cancer-selective toxicity, providing the ability to deliver much larger doses of the drug to solid tumour. In the presence of a stimulus, prodrugs undergo a chemical transformation and “unmask” to afford the corresponding cytotoxic chemotherapeutic. Exploiting the high-energy photons (X-rays, γ rays) and charged particles (electrons, α-, and β- emitters) generated from radiation to activate prodrugs will immediately synergise with clinically used, chemoradiotherapy. Several prodrug strategies will be explored in this project. These new prodrugs will be referred to as radiotherapeutics. The project will therefore be multidisciplinary, involving chemistry, imaging and cell- and radiobiology and will follow an iterative systematic testing pipeline between chemistry and biology.
Year 1 - Synthesise radiation-activated prodrugs. Radiation training (X-rays and radioactivity). Training in cell culture techniques and development of assays for screening of the radiation-mediated activated of small molecules.
Year 2 - Fluorescence microscopy of cells and tumour spheroids. 2D and 3D viability experiments will be performed in combination with different radiotherapy types e.g. Auger electron, alpha and/or beta particles emitters. The focus will be towards identifying a lead prodrug only displaying cytotoxicity when activated by radiation.
Year 3 – Other potential prodrug strategies will be developed. The promising prodrug strategies determined in solution studies will be studied in vitro against a panel of different cancer cell lines.
Year 4 - In vivo studies will be carried out to understand dosing and radiation scheduling for a lead prodrug candidate. By the end of the project, we will have developed a new chemical entity that has impact in chemoradiotherapy that will form the basis of further grant capture and preclinical development.
Enquiries please contact:
Project 1: Professor Elinor Sawyer ( elinor.sawyer@kcl.ac.uk)
Project 2: Dr Miguel Reis Ferreira (Miguel.reisferreira@kcl.ac.uk)
Project 3: Dr Graeme Stasiuk (graeme.stasiuk@kcl.ac.uk)
Project 4: Dr Adam Sedgwick (Adam.sedgwick@kcl.ac.uk)
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