Defining the role of the IgE-Fc epsilon receptor-1 immune surveillance axis in human cutaneous squamous cell carcinoma

Context of research:
Skin cancer is the most common human cancer and cutaneous squamous cell carcinoma (cSCC) is the second most common form. cSCC is caused mainly by ultraviolet radiation (UV) from sun exposure. At least 30,000 new cases occur every year in the UK and cSCC is more common in patients with compromised immune systems. Most cSCC are treated surgically, but this may cause significant problems, given that 70% are on cosmetically sensitive head and neck locations and many patients develop more than one cSCC. Advanced (metastatic) cSCC with spread to lymph nodes or internal organs occurs in up to 5% and current treatments have poor responses, although recent evidence suggests immunotherapy may be promising. Nonetheless, advanced cSCC remains an area of important unmet clinical need.

In previous research, we showed that genetic damage is higher in cSCC than in almost any other cancer (probably because UV is very mutating) and also that immune genes are particularly mutated in cSCC at high risk of metastasis, including the immune gene Fc epsilon receptor 1 (FCER1). We showed that in response to skin damage (e.g. UV or chemicals), the antibody IgE is released by cells and this results in increased numbers of immune cells containing the protein FceR1 which act to defend the body against skin cancer. This interaction affects how the immune system suppresses skin cancer in mice: when the IgE-FceRI interaction is reduced, skin cancer risk is increased.

Aims and methods:
We will investigate how IgE-FceRI interactions control cSCC development and whether this affects risk of metastasis. We will first examine which cSCC immune cells carry the receptor by a detailed analysis of fresh tumours using a technique which allows us to identify the exact type of immune cells present and whether or not they carry FceRI (FceRI+). We will particularly look for differences between low-risk, high-risk and metastatic cSCC. We will then investigate the precise location of FceRI+ immune cells in tumours as this may provide further information on their role in cSCC. We will use a technique in which whole tumour sections are examined and the exact location of cells can be identified. These results will be confirmed in a larger series of cSCC using antibodies to FceRI+ cells. We will ask whether the presence and location of FceRI+ cells are associated with metastatic risk and whether FceRI is a marker for increased risk. We will also test for the activity of the FceRI gene in this larger series of samples and will again investigate if this is associated with cSCC that metastasise. In the final series of experiments we will investigate whether altering IgE-FceRI interactions has an effect on cSCC growth. We will use cSCC cell lines that we have previously grown from patients and also small fresh cSCC samples and will add drugs that either block or increase IgE-FceRI interactions and see how this changes the behaviour of cancer cells. Finally, we will transplant human cSCC samples into mice, either by inserting a small piece of tumour or injecting suspensions of tumour cells into the mouse skin. Blocking and stimulating drugs will again be used to examine effects on cSCC growth and the resulting tumours will be analysed in detail for the presence of the immune cells and FceRI.

Potential applications and benefits:
In summary, our previous research has suggested an important role for IgE-FceRI in cSCC. We will investigate the presence and location of FceRI-expressing cells in cSCC and whether this influences the risk of tumours progressing. We will also examine whether blocking or stimulating this interaction has an effect on tumour growth. Ultimately, this research will improve our understanding of how cSCCs develop. It may also provide important markers for predicting which cSCC are at high risk of metastasis. Finally, it may also provide important directions for developing new treatments suitable for advanced cSCC.

Background:
Cutaneous squamous cell carcinoma (cSCC) is the second most common skin with around 30,000 new cases per year in England. Up to 5% of cSCCs metastasise with 3-year overall survival 29% in women, 46% in men. The immune system is known to have a key role in the aetiology of cSCC. Our group and my co-supervisor's group have independently generated data implicating a novel role for the IgE-FceRI immune signalling axis in cSCC pathogenesis and progression.

Aim:
To characterise the FceRI-expressing cells present in cSCC and define the role of the IgE-FceRI immune surveillance axis in cSCC progression and metastatic disease.

Objectives:
1. Define the composition and tissue localisation of leucocytes including FceRI+ cells in cSCC. 2: Validate and quantify FCER1A and other immune gene and protein expression as correlates for increased metastatic risk 3: Functional experiments by manipulation of the IgE-FceRI axis in vitro/in vivo.

Methods:
1. Multi-parameter flow cytometry and imaging mass cytometry will define the immune cells (including FceRI+) and their spatial localisation. 2. Immunohistochemistry and targeted RNAseq in a larger cohort of archival cSCC will examine and quantify expression of FCER1A and associated selected immune genes. 3. In vitro transwell co-culture with immune cells and cSCC cell lines and mouse patient derived xenografts will be used in functional experiments in which the IgE-FceRI axis will be manipulated and downstream effects measured and compared.

Scientific and medical opportunities:
This project will define an exciting and novel immune signalling checkpoint that is based on compelling preliminary data. It offers the potential to discover important biomarkers for identification of high-risk primary cSCC and novel therapeutic directions for treatment of advanced cSCC whilst providing a varied, multi-disciplinary research training experience.

Academic sector: The proposed research aims to dissect the role of the IgE-FceRI axis in cSCC and define whether this is important in progression to metastatic disease. This has the potential to have a large impact on the national and international cSCC community as this immune checkpoint is relatively unexplored in skin tumourigenesis. If important, it is likely this will be a paradigm for all squamous cancers with potential for pan-cancer biology impact.

Private sector: The IgE- FceRI axis may represent a druggable immune checkpoint relevant to advanced cSCC. It therefore has the potential to be of significant interest to the pharmaceutical industry in terms of developing novel therapies for advanced cSCC and also as adjuvant therapies for high risk primary cSCC. This is an area of considerable research interest at present with recent evidence of activity of anti-PD1 immunotherapy in metastatic cSCC. My supervisors and the UK Keratinocyte Cancer Collaborative already have in place collaborations with pharmaceutical companies (Galderma, Biosceptre, Pellepharm, Sanofi) and a collaboration with the Dundee Drug Discovery Unit. This collaborative network will be important in future development of novel, putative druggable targets that are discovered through my proposal. Such partnership with the pharmaceutical industry early on may be critical if translational benefit to patients is to be realised.

Public sector: Within the public sector, we anticipate that the NHS will be a key beneficiary of outputs from this research proposal. Ultimately, our results may lead to improvements in cSCC management of significant benefit to patients in an area of important and rapidly increasing unmet clinical need. If this research leads to partnerships with industry, then the NHS will also profit as a partner. Any translational benefit from this research will ultimately be delivered within the NHS and therefore engagement at the local level (NHS Trust) and national level (NHS England) will be key to drive forward any new innovations that could improve patient outcomes and reduce costs. An additional benefit of this innovation will come from raising the profile of the NHS in the global healthcare arena as innovation and new technologies and therapeutics will attract international attention and potentially investment.

Government policy makers are likely to be interested in any research outputs if they have potential to influence patient outcomes and healthcare costs - which new therapeutics for advanced cSCC may indeed do. Guideline and policy makers (such a National Institute for Health and Care Excellence and British Association of Dermatologists) may also be positively impacted from this research if it leads to the introduction of new treatments and biomarkers. Any change to healthcare policy is likely to be a longer term possibility, but may prove to be relevant if strong evidence for therapeutic efficacy and/or biomarker utility emerges.

Patient support groups and skin cancer charities will also be interested in my research and I plan to engage with them early on. With risk of cSCC so significantly increased in the immunosuppressed population as well as in several genetic disorders, patient support groups are in an ideal position to benefit and disseminate research outputs.

The community: the local community will benefit from my research programme through my communications plan and patient and public involvement plan. The 'Centre of the Cell' platform at the Blizard Institute will be an important resource for engaging with and informing members of the public, including local school children, about my research. Scientists and clinicians in the Blizard are encouraged to take an active part in these public engagement activities, and I am enthusiastic about the opportunities to do so: presenting my research findings at an appropriate level may ultimately inspire a new generation of researchers.