Understanding the oncogenic mediated pro-inflammatory environment in stem cell driven hypothalamic pituitary tumours

Craniopharyngiomas (CPs) are tumours that originate from embryological cells of the pituitary gland. They affect both children and adults with peak incidences at 5-14 years and again at 50-74 years. They are aggressive tumours that lead to hormone loss from the pituitary gland which affects growth, fertility, metabolism, stress response, lactation and water balance. They invade surrounding structures such as the optic and cranial nerves (leading to visual loss) and the hypothalamus, which regulates key vital functions of body temperature and appetite.

There are two types of CP, adamantinoumatous (ACPs) which have been associated with a mutation in the B-catenin gene and papillary (PCPs) associated with a mutation in the BRAF gene.

Current treatment involves invasive neurosurgery and radiotherapy, which are associated with significant morbidity. Furthermore, despite this the incidence of tumour regrowth is very high. Importantly, there are no pharmacological treatments for these tumours and there is an urgent need to understand how these tumours grow and develop in order to change and identify new treatments.

My research will concentrate on preliminary results, which strongly suggest that these tumours create an immune response that leads to local inflammation. These responses are not well understood, but are able to create an environment that benefits these tumours helping them evade the bodies immune system and hence making them more aggressive.

I will be using a genetically modified mouse to identify and investigate the role of inflammation in the early development and progression of CPs. In parallel, I will be using human CP samples to investigate whether there is a correlation between the degree of inflammation within CPs and the incidence of tumour recurrence.

My underlying hypothesis is that by understanding the inflammatory response that leads to CP formation and progression, I will be able to modify it, hence changing the tumour environment and slowing tumour growth. This could potentially lead to the exciting discovery of new pharmacological treatments that could slow CP growth and prevent tumour recurrence.

Craniopharyngiomas (CPs) are tumours thought to arise from embryological remnants that form the pituitary. Two subtypes exist; adamantinoumatous associated with oncogenic B-catenin (ACPS) and papillary associated with mutations in BRAF (PCPs). Treatment of these aggressive tumours consists of neurosurgical resection and radiotherapy. There are no licenced pharmacological treatments for CPs.
The association between inflammation and cancer is well established, however, this has not been investigated in CPs. My preliminary data highlights an up-regulation of pro-inflammatory markers in both mouse and human ACPs. I hypothesize that some of the first genes up-regulated after oncogenic activation in CPs are pro-inflammatory and that their inhibition will slow development and progression.
I have developed a unique mouse model of CPs which allows activation of oncogenes at a specific time point within pituitary stem cells. To identify early up-regulated pro-inflammatory genes, RNA-seq will be performed on mouse pituitaries harvested up to 1 week after oncogene activation. Simultaneously, cells from pituitaries will be cultured and the secretome analysed via lipidomics, ELISA and IHC. To investigate inhibition of pro-inflammatory markers on CP development, mice and cultured cells will be treated with anti-IL6. In parallel, two pro-inflammatory genes will be genetically ablated within a new mouse model.
I have one of the largest cohorts of human CPs consisting of over 200 samples. IHC for inflammatory markers within human CPs will be quantified and correlated with clinical phenotypic data to investigate an association between the degree of inflammatory infiltrate and incidence of tumour recurrence.
Confirming a pivotal role of pro-inflammatory genes in the early development of CPs could lead to clinical trials using anti-inflammatories as adjuvant or neoadjuvant therapies, thereby reducing rates of recurrence and improving the quality of life for patients with CPs.

The most important people to benefit from long-term outcomes of this research will be patients and family members of those with CPs. CPs are aggressive tumours which invade vital structures and can lead to severe morbidity such as multiple endocrinopathies and blindness. Current management consists of neurosurgical resection and radiotherapy. However, these tumours often have a propensity to reoccur and patients may require multiply neurosurgical interventions during their lifetime. Furthermore, the majority are left with at least one, if not multiple hormone deficiencies which require lifelong treatment. There are currently no licenced pharmacological treatments for these tumours. I hope to identify a pivotal role of inflammation in the development of CPs. If this is proven, I will have identified a potential therapeutic target in the early pro-inflammatory gene signature that can change the tumour microenvironment to slow down tumour growth and potentially prevent tumour recurrences.

Current best practice is subtotal resection if the CP has already invaded the cavernous sinus or hypothalamus in order to preserve hypothalamic and cranial function. However, there is a higher degree of recurrence associated with subtotal resection and radiotherapy can take 8-10 years to be fully effective. Based on the proposed outcomes of my research there may be a potential role of anti-inflammatory medications as a neo-adjuvant therapy to try and decrease tumour size and burden, thereby facilitating a more aggressive neurosurgical resection. Furthermore, in patients whom only subtotal resection was feasible there may be an adjuvant role for anti-inflammatories to decrease the incidence of recurrence. Clearly any therapy that avoids or decreases tumour recurrence will not only improve quality of life for patients but also decrease the burden that this chronic condition places on the NHS as a whole.

Following on from my proposed project clinical trials would have to be completed to investigate the role of anti-inflammatories in human CPs. Therefore, there may be an interest in my potential research findings from pharmaceutical companies. If clinical trials do indeed show an important role of anti-inflammatories as either a neoadjuvant or adjuvant therapy, best practice national and international guidelines may change.

My research will also benefit other researchers within my field by highlighting a new and important role of inflammation in the early formation of these tumours. I am concentrating on understanding the pro-inflammatory gene signature and how it modifies the tumour microenvironment downstream of oncogenic B-catenin and BRAF. These results may also be of use and interest to researchers working within other cancers associated with these 2 oncogenes including prostate, liver, breast, colon and skin cancer.

Central to my research is the use of a unique inducible genetic mouse model, which on tamoxifen injection activates the oncogene within Sox2 positive stem cells under a fluorescent protein reporter. To our knowledge the use of a tamoxifen inducible mouse model to look early (i.e. first 46-72 hours) after any oncogenic activation has not been achieved. Therefore, these mice may be of interest to other researchers investigating oncogenic B-catenin and BRAF within other cancers.