Dr. Melissa Conroy
Assistant Professor, Anatomy

Projects

• Title
  • Targeting T cell trafficking as a novel means to control obesity-associated chronic inflammation.
• Summary
  • Obesity is a global health problem affecting millions of adults and children worldwide. In Ireland, approximately 66% of adults and 25% of children are overweight or obese and are therefore at serious risk of developing obesity-associated diseases. Obesity induces organ and whole body chronic inflammation. It is the active infiltration of immune cells into expanding visceral adipose tissue (VAT) that causes this inflammation in obesity and studies have shown that T cells are predominantly responsible for this. VAT surrounds abdominal organs and its expansion is closely associated with obesity-related pathologies including many types of cancer and liver disease. Therefore, we propose that preventing T cells from infiltrating the VAT will prevent or reduce local and systemic inflammation and as a result the associated comorbidities. Proteins known as chemokines are responsible for guiding the migration of immune cells during normal immune responses and it is now well documented that chemokines mediate the natural cycling of T cells to the liver. However, previous murine studies have implicated dysregulated chemokine production in the recruitment of inflammatory cells to the VAT in obesity. Our recent work has revealed preferential movement of T cells to human VAT and liver and have identified two key chemokines guiding this movement; macrophage inflammatory protein 1α (MIP-1α) and interferon-inducible protein 10 (IP-10). Therefore, we propose that a therapeutic strategy specifically blocking MIP-1α- and IP-10-guided inflammatory T cell trafficking to the VAT and liver using novel chemokine receptor antagonists will prevent and reduce both local and systemic chronic inflammation in obesity. For the first time, this innovative study will validate a novel immunotherapeutic strategy targeting immune cell trafficking, which has significant potential to prevent and reduce the detrimental consequences of obesity-associated inflammation, as a major driver of carcinogenesis and liver disease, in the rapidly growing number of obese individuals worldwide.
• Funding Agency
  • Irish Research Council
• Date From
  • 01/10/2015
• Date To
  • 31/03/2018

• Title
  • Harnessing natural killer cell-mediated immune responses in obesity-associated cancer" "
• Summary
  • Oesophagogastric adenocarcinomas (OAC) encompass a group of inflammation-driven and obesity-associated cancers. Poor 5-year survival rates of less than 20% and treatment response rates of less than 30% place these as poor prognosis cancers, in urgent need of new therapeutic options. As immunotherapy emerges as the fourth pillar of cancer treatment and immune dysregulation in OAC has been uncovered, we propose that novel immunotherapeutic approaches can improve treatment efficacy and outcomes in the growing number of OAC patients. Natural killer (NK) cells are lymphocytes of the innate immune system which function as cytotoxic mediators and key cytokine producers. However, NK cells are severely dysregulated in obesity with phenotypic and functional alterations compromising their anti-tumour abilities. Furthermore, a number of studies have shown that low infiltration of NK cells into solid tumours is associated with poorer prognosis. Therefore, NK cell-based immunotherapies hold great promise to overcome immune dysfunction in cancer. However, two key issues are known to compromise their efficacy: namely successful infiltration of solid tumours and the immunosuppressive tumour microenvironment (TME). In the context of OAC, we have reported active recruitment of NK cells to extratumoural tissues namely the omentum and believe that this compromises their infiltration of the tumour. We have previously reported that such erroneous migration is mediated by the Fractalkine:CX3CR1 axis and propose that CX3CR1 antagonism may be employed to limit this. In this thesis, we have explored the therapeutic applicability of CX3CR1 antagonism to boost NK cell infiltration of tumours in OAC. We have profiled NK cells in OAC patient-derived blood, omentum and tumour samples unearthing unique phenotypes within these compartments and identifying immune dysregulation in the most viscerally obese OAC patients. Importantly, we have identified that the frequencies of intratumoural NK cells are lowest in the most viscerally obese OAC patients, highlighting how detrimental visceral obesity is for anti-tumour immunity in these patients. Furthermore, we have explored the impact of the soluble microenvironments of adipose and tumour tissues derived from viscerally obese and non-obese OAC patients and unveiled divergent effects of these microenvironments on NK cell phenotype and function. Interestingly, our data have revealed that the obese TME impairs NK cell cytotoxicity, thus emphasising the importance of immunotherapeutic approaches to overcome immunosuppressive signalling in OAC. Fractalkine has been previously reported as a driver of obesity-association inflammation, both by our group and others. Our group have previously reported that fractalkine is a key driver of NK and CD8+ T cell migration to the omentum in OAC and uncovered its non-chemotactic effects on CD8+ T cells. Here, we examined the effects of physiologically relevant levels of fractalkine on the phenotype and function of NK cells. Our data revealed that fractalkine mediates the endocytosis of CX3CR1 on the surface of NK cells, increased CD27 expression and shifts NK cell phenotype towards a pro-inflammatory cytokine profile, thus further implicating this chemokine in the potentiation of omental inflammation in obesity. Furthermore, we identified a role for fractalkine in antagonising IL-15-mediated activation of NK cells, highlighting the potential multi-faceted benefits that CX3CR1 antagonism could confer in OAC. Finally, in this thesis, we have developed a novel OAC patient-derived ex vivo model to study immune cell migration between different tissue compartments. Using this platform our data showed that when simultaneously exposed to the chemotactic cues of OAC patient-derived omentum and tumour, NK cells preferentially migrate towards the soluble chemotactic cues of the omentum.
• Funding Agency
  • Breakthrough Cancer Research
• Date From
  • 01/09/2019
• Date To
  • 31/03/2023

• Title
  • Elucidating the potential of combination Olaparib and Natural Killer cell therapy in non-small lung cancer.
• Summary
  • This multi-investigator collaboration will integrate the cancer immunology and treatment resistance expertise of Dr Conroy and Dr Barr, together with the clinical expertise of Dr Sinead Cuffe, to generate novel, clinically-relevant data on the therapeutic utility of Olaparib in combination with NK cell therapy for NSCLC. This multidisciplinary study will assess the use of novel treatment combinations to address the clinical challenge of treatment-resistant NSCLC tumours. Innovative and transformative treatments are urgently needed to overcome abysmal survival rates in NSCLC and we propose that Olaparib holds significant potential to boost the efficacy of NK cell therapy and promote tumour eradication. The proposed study is based on compelling published by Dr Conroy demonstrating that treatment-resistant tumours are less susceptible to NK cells [1], together with published work by others [2] and pilot data by Dr Barr [Fig.1] that Olaparib can sensitise such tumours to NK cells. Here, we will examine whether Olaparib can sensitise treatment-resistant NSCLC cells to NK cells and to the FDA approved NK cell therapy, NK92. By assessing the effects of Olaparib on NK cell therapy, this first-of-its-kind study in drug-resistant NSCLC, has the additional potential to elucidate new mechanisms of action which may have consequences for enhancing the anti-tumour immune response and improving the efficacy of immunotherapies in other malignancies.
• Funding Agency
  • Trinity St. James Cancer Institute
• Date From
  • 01/09/2024
• Date To
  • 31/08/2025

• Title
  • Boosting the heat on cold tomours; Augmenting susceptibility of solid malignancies to natural killer cell therapies
• Summary
  • Overall objective: To maximise efficacy of NK cell therapies for solid tumours via therapeutic manipulation of tumour-specific chemokine gradients and danger-associated surface molecules. Summary: Tumour burden and cancer patient outcomes are heavily affected by the level of immune cell infiltration in the tumour. Immune cell therapies such as chimeric antigen receptor (CAR) T cells involve infusion of genetically-engineered immune cells to enhance immune infiltration of tumour and boost anti-tumour immunity. So far, they are FDA-approved for 2 blood cancers. Their utility for solid malignancies are challenged by; lack of identifiable tumour-specific antigens; immunosuppression by the tumour; and poor quality of patient-derived cells. Natural Killer (NK) cells are critical immune cells in tumour eradication and are superior to T cells for immune cell therapies. Unlike T cells, they do not require antigen specificity and can be generated from healthy donors to facilitate large-scale immunotherapy. For the first time, this research will confirm how tumour susceptibility to NK cell therapies can be potentiated by maximising NK cell migration to the tumour and tumour killing in solid malignancies with low survival rates. Importantly, this study will establish whether current and novel anti-cancer treatments can enhance the effectiveness of NK cell therapy, particularly for treatment-resistant solid tumours of the upper gastrointestinal tract that have a paucity of alternative treatment options. Furthermore, in light of the current obesity epidemic and our previous reports of misdirected immune cell migration to adipose tissue in obesity-associated cancer, we will develop a novel human model of obesity-associated cancer to establish how our therapeutic approach should be tailored to successfully treat cancer in obese patients. This model will offer a unique and urgently needed platform to conduct immunological studies in obesity-associated cancer. Finally, this timely study will also establish whether a pre-screened panel of soluble NK cell receptor ligands are valuable serum biomarkers for clinical outcomes and viable therapeutic targets in cancers with poor prognosis. This research will confirm the utility of an advanced immunotherapy and predictive biomarkers to ultimately improve outcomes for cancer patients.
• Funding Agency
  • Enterprise Ireland
• Date From
  • 01/05/2019
• Date To
  • 31/07/2020

• Title
  • Identifying the therapeutic potential of novel compounds in glioblastoma multiforme.
• Summary
  • Glioblastoma multiforme (GBM) is the most common and aggressive brain cancer in adults with a dismal 5-year survival rate of <5%. Despite advanced diagnostic and multimodal treatments including surgery, followed by radiotherapy and temozolomide chemotherapy (CRT), the survival rates for GBM are not improving. Therefore, innovative therapeutic approaches are urgently needed for these patients. Pyrazinib (P3) and Q8 are novel anti-angiogenic, anti-metabolic and radio-sensitizing compounds which have shown significant therapeutic potential in both oesophageal and colorectal cancer models. The first strand of this research initiative will assess whether the therapeutic utility of these drugs can be extended to GBM and whether they can sensitise GBM tumours to current modes of CRT. Natural Killer (NK) cells are potent anti-tumour immune cells and are gaining momentum as an adept alternative to T cell immunotherapies. Our pilot data indicate that P3 can render cancer cells as more visible to NK cells. Here we will investigate the utility of P3 and Q8 in sensitising GBM tumours to NK cell-mediated killing. At a time when immunotherapy is transforming patient outcomes in multiple poor prognosis cancers, we propose that combination immunotherapies hold significant potential to improve abysmal survival rates for GBM patients.
• Funding Agency
  • Faculty of Health Sciences, Trinity College Dublin
• Date From
  • 01/01/2022
• Date To
  • 16/12/2022

• Title
  • Therapeutically targeting T cell trafficking in obese in vivo models using CCR1 antagonism
• Summary
  • The global health burden of obesity is of grave concern, affecting over half a billion adults worldwide, and directly attributable to approximately 3.5 million deaths each year. In addition, WHO figures show that 1 in 3 European children are overweight or obese and of these, 60% are predicted to be obese in adulthood. Furthermore, despite national and international interventions to promote a healthy diet and lifestyle, recent reports predict that global obesity rates show no signs of abating and therefore large numbers of adults and children are at serious risk of developing obesity associated diseases such as cancer. Obesity induces organ and whole body chronic inflammation. It is the active infiltration of immune cells into expanding visceral adipose tissue (VAT) that drives this inflammation in obesity and studies have shown that T cells are key players in this process. VAT surrounds abdominal organs and its expansion is closely associated with obesity-related pathologies. Therefore, we propose that preventing T cells from infiltrating the VAT will prevent or reduce local and systemic inflammation and as a result the associated comorbidities. Proteins known as chemokines are responsible for guiding the migration of immune cells during normal immune responses and it is now well documented that chemokines mediate the natural cycling of T cells to the liver. However, previous studies have suggested excessive chemokine production from obese VAT results in the dysregulated recruitment of inflammatory cells. Our recent work in patients with obesity-associated cancer, has revealed preferential movement of T cells to human VAT and liver and have identified macrophage inflammatory protein 1" (MIP-1") as a key chemokine guiding this movement. Therefore, we propose that a therapeutic strategy to specifically block MIP-1"-guided inflammatory T cell trafficking to the VAT and liver using novel chemokine receptor antagonists will attenuate local and systemic chronic inflammation in obesity. We have already demonstrated in vitro that a novel CCR1 antagonist (Chemocentryx) can effectively block human T cell chemotaxis to secreted factors from VAT and liver. However, anti-inflammatory effects of the drug cannot be tested in such ex vivo settings using tissue explants and therefore the use of an in vivo model is crucial to the advancement of this research. For the first time, the proposed study would validate a novel immunotherapeutic strategy in an in vivo model of obesity. Non-obese and diet-induced obese C57BL/6 mice will be administered with a CCR1 antagonist (Chemocentryx). This treatment regime would determine the effects of CCR1 blockade on T cell infiltration to VAT and liver and its ability to alleviate pre-existing obesity-associated inflammation. This would indicate whether such a therapeutic intervention can successfully control inflammation and whether it can be used to treat/prevent obesity-associated disease. In addition, C57BL/6 mice will be administered with a CCR1 antagonist (Chemocentryx) during the development of diet induced obesity. This prophylactic treatment regime would determine the effects of CCR1 blockade on obesity associated inflammation during the development of obesity and will indicate whether intervention can successfully prevent inflammation and disease. Professor Thomas Wunderlich is an internationally renowned principle investigator at the Max Planck Institute (MPI) for metabolic research with major interest in the area of obesity and cancer. Prof. Wunderlich is well-published in the area of obesity with a multitude of publications in high-impact journals. His team routinely use C57BL/6 mice to generate mouse models of obesity and cancer. Therefore, his research group is an ideal choice for generating the mouse models during the project and shall be the catalyst in propelling our study toward clinical trials.
• Funding Agency
  • European Association for Cancer Research
• Date From
  • 12/01/16
• Date To
  • 26/04/19

• Title
  • Therapeutically Remodelling the Immune Profile of `Cold" Tumours in Obesity-associated Cancer.
• Summary
  • Oesophageal adenocarcinoma (OAC) is an obesity-associated cancer with a dismal survival rate of ~20%. Natural killer (NK) cells are crucial anti-cancer immune cells and their lower prevalence in oesophageal tumours is associated with poorer prognosis. We have reported that the chemokine fractalkine recruits NK cells to the visceral adipose tissue (VAT) in OAC, where they undergo functional alterations and cell death. Consequently, the most obese OAC patients have the lowest numbers of intratumoural NK cells, contributing to `cold" or `immune-excluded" tumours. Approximately 70% of OAC patients do not respond to chemoradiotherapy and we have identified that poor treatment responders have lower numbers of NK cells. Therefore, we propose that they would benefit from immunotherapies that reinvigorate NK cell-mediated anti-tumour immunity. We have demonstrated that antagonism of the fractalkine receptor CX3CR1 rescues NK cells from the VAT and directly reduces the viability and metastasis of OAC tumour cells, therefore offering a 2- pronged approach to tumour eradication. We will use OAC patient samples and a novel humanized in vivo model to establish the clinical utility of CX3CR1 antagonism to promote tumour eradication by; 1) redirecting NK cells from VAT to tumour and 2) directly impeding tumour growth and metastasis. We will also assess the utility of a highly cytotoxic and fractalkine-resistant tumour-homing NK cell based immunotherapy to; 1) bypass the VAT and 2) infiltrate and eradicate OAC tumours. This study will confirm the utility of two novel immunotherapies to remodel the immune landscape of oesophageal tumours and ultimately improve OAC patient survival.
• Funding Agency
  • Breakthrough Cancer Research
• Date From
  • 01/03/2022
• Date To
  • 28/02/2027

• Title
  • Interrogation of the neuroinflammatory impact of mast cells in brain tumour related epilepsy (BTRE)
• Summary
  • Brain tumour related epilepsy (BTRE) is defined as symptomatic epileptic seizures secondary to gliomas. BTRE is debilitating, difficult to control and seizures are closely related to recurrence/progression of the tumour1 . Increasing seizure burden and anti-seizure medication (ASM) use is associated with reduced cognitive performance and dramatically reduced physical and mental health. Therefore, given the limited efficacy of surgical, oncological and pharmacological treatments for BTRE, there is an urgent need to better characterise this condition. Many cancers maintain complex inflammatory mechanisms which trigger rapid recruitment of inflammatory cells, including mast cells (MC). MCs are multifunctional immune cells activated in response to stress and importantly, MC infiltration is inversely correlated to glioma grade, with greater infiltration observed in higher grade tumours2 . Critically, MCs produce a range of mediators such as cytokines (for e.g. IL-10, IL-16, IL-1b), histamine, neurotransmitters (for e.g., serotonin (5-HT)), chemokines, enzymes and growth factors3 which may have positive or negative effects on biological processes. Indeed, MC release of serotonin4 and histamine5 may elicit antiepileptic and neuroprotective effects, with serotonin demonstrated to reduce seizure activity in a pentylenetetrazole (PTZ)-induced seizure model4 and histamine-3 receptor (H3) agonism under investigation for its antiepileptic effects5 . In contrast, evident demonstrates that MCs play a pro epileptic role via a range of pro-inflammatory cytokines including TNF, IL-16 and IL-1b6 . Moreover this pro-inflammatory phenotype has been shown to be modulated by glutamate7 , a neurotransmitter abundantly expressed in the glioma peritumoral region. Nevertheless, despite the potential role of MCs in both driving and silencing epileptic processes, the function and activity of MCs in BTRE has not been previously elucidated. This study therefore aims to interrogate the impact of MC degranulation and mediator release in BTRE related neuroinflammation and epileptogenesis. Aim 1: Identify peritumoral infiltration patterns of mast cells in low grade vs high grade BTRE. Aim 2: Examine the impact of MC mediator release on tumour related seizure generation and propagation
• Funding Agency
  • Trinity St. James's Cancer Institute
• Date From
  • 01/09/2024
• Date To
  • 31/08/2025

• Title
  • Key Skills for Biomedical Research
• Summary
  • This grant facilitated the delivery of statistical workshops for the 5 ECT module "Key Skills for Biomedical Research" and covered the cost of PRISM licences for this component of the module, alleviating the costs for PhD students undertaking the module
• Funding Agency
  • Irish Statistical Association
• Date From
  • 01/03/2023
• Date To
  • 01/06/2023