Visceral Adipose Tissue Modulates Radiosensitivity in Oesophageal Adenocarcinoma.

Oesophageal adenocarcinoma (OAC) is an exemplar model of obesity-associated cancer. Response to neoadjuvant chemoradiotherapy (NA CRT) is a clinical challenge. We examined if visceral adipose tissue and obesity status alter radiosensitivity in OAC. The radioresistant (OE33R) and radioresponsive (OE33P) OAC isogenic model was cultured with adipose tissue conditioned media from three patient cohorts: non-cancer patients, surgery only OAC patients and NA CRT OAC patients. Cell survival was characterised by clonogenic assay, metabolomic profiling by nuclear magnetic resonance spectroscopy and adipokine receptor gene expression by qPCR. A retrospective in vivo study compared tumour response to NA CRT in normal weight (n=53) versus overweight/obese patients (n=148). Adipose conditioned media (ACM) from all patient cohorts significantly increased radiosensitivity in radioresistant OE33R cells. ACM from the NA CRT OAC cohort increased radiosensitivity in OE33P cells. Metabolomic profiling demonstrated separation of the non-cancer and surgery only OAC cohorts and between the non-cancer and NA CRT OAC cohorts. Gene expression profiling of OE33P versus OE33R cells demonstrated differential expression of the adiponectin receptor-1 (AR1), adiponectin receptor-2 (AR2), leptin receptor (LepR) and neuropilin receptor-1 (NRP1) genes. In vivo overweight/obese OAC patients achieved an enhanced tumour response following NA CRT compared to normal weight patients. This study demonstrates that visceral adipose tissue modulates the cellular response to radiation in OAC.

Low miR-187 expression promotes resistance to chemoradiation therapy in vitro and correlates with treatment failure in patients with esophageal adenocarcinoma.

Esophageal adenocarcinoma (EAC) has a poor prognosis and is increasing in incidence in many western populations. Neoadjuvant chemoradiation therapy (CRT) followed by surgery is increasingly the standard of care for locally advanced EAC; however, resistance to treatment is a significant clinical problem. The identification of both novel biomarkers predicting response to treatment and novel therapeutic targets to enhance the efficacy of CRT are key to improving survival rates in EAC. In this study we performed global microRNA (miRNA) profiling of pre-treatment EAC biopsies and identified 67 miRNA significantly altered in patients who are resistant to CRT. One of these miRNA, miR-187, was significantly decreased in pre-treatment EAC tumors from patients having a poor response to neoadjuvant CRT, highlighting downregulation of miR-187 as a potential mechanism of treatment resistance in EAC. In vitro, miR-187 was demonstrated to play a functional role in modulating sensitivity to X-ray radiation and cisplatin in EAC and its dysregulation was demonstrated to be due to chromosomal alterations. In vitro, miR-187 altered expression of a diverse array of pathways, including the immune regulator complement component 3 (C3), serum levels of which we have previously demonstrated to predict patient response to CRT. In vivo, expression of C3 was significantly increased in tumors from patients having a poor response to CRT. This study highlights for the first time a role for miR-187 as a novel biomarker of response to CRT and a potential therapeutic target for enhancing the efficacy of CRT in EAC.

CCR1 antagonism attenuates T cell trafficking to omentum and liver in obesity-associated cancer.

Obesity is a global health problem presenting serious risk of disease fuelled by chronic inflammation, including type 2 diabetes mellitus, cardiovascular disease, liver disease and cancer. Visceral fat, in particular the omentum and liver of obese individuals are sites of excessive inflammation. We propose that chemokine-mediated trafficking of pro-inflammatory cells to the omentum and liver contributes to local and subsequent systemic inflammation. Oesophagogastric adenocarcinoma (OAC) is an exemplar model of obesity and inflammation driven cancer. We have demonstrated that T cells actively migrate to the secreted factors from the omentum and liver of OAC patients and that both CD4(+) and CD8(+) T cells bearing the chemokine receptor CCR5 are significantly more prevalent in these tissues compared to matched blood. The CCR5 ligand and inflammatory chemokine MIP-1α is also secreted at significantly higher concentrations in the omentum and liver of our OAC patient cohort compared to matched serum. Furthermore, we report that MIP-1α receptor antagonism can significantly reduce T cell migration to the secreted factors from OAC omentum and liver. These novel data suggest that chemokine receptor antagonism may have therapeutic potential to reduce inflammatory T cell infiltration to the omentum and liver and in doing so, may ameliorate pathological inflammation in obesity and obesity-associated cancer.

Excess visceral adiposity induces alterations in mitochondrial function and energy metabolism in esophageal adenocarcinoma.

BACKGROUND: Visceral obesity has a strong association with both the incidence and mortality of esophageal adenocarcinoma (EAC). Alterations in mitochondrial function and energy metabolism is an emerging hallmark of cancer, however, the potential role that obesity plays in driving these alterations in EAC is currently unknown. METHODS: Adipose conditioned media (ACM) was prepared from visceral adipose tissue taken from computed tomography-determined viscerally-obese and non-obese EAC patients. Mitochondrial function in EAC cell lines was assessed using fluorescent probes, mitochondrial gene expression was assessed using qPCR-based gene arrays and intracellular ATP levels were determined using a luminescence-based kit. Glycolysis and oxidative phosphophorylation was measured using Seahorse XF technology and metabolomic analysis was performed using 1H NMR. Expression of metabolic markers was assessed in EAC tumor biopsies by qPCR. RESULTS: ACM from obese EAC patients significantly increased mitochondrial mass and mitochondrial membrane potential in EAC cells, which was significantly associated with visceral fat area, and was coupled with a significant decrease in reactive oxygen species. This mitochondrial dysfunction was accompanied by altered expression of 19 mitochondrial-associated genes and significantly reduced intracellular ATP levels. ACM from obese EAC patients induced a metabolic shift to glycolysis in EAC cells, which was coupled with significantly increased sensitivity to the glycolytic inhibitor 2-deoxyglucose. Metabolomic profiling demonstrated an altered glycolysis and amino acid-related signature in ACM from obese patients. In EAC tumors, expression of the glycolytic marker PKM2 was significantly positively associated with obesity. CONCLUSION: This study demonstrates for the first time that ACM from viscerally-obese EAC patients elicits an altered metabolic profile and can drive mitochondrial dysfunction and altered energy metabolism in EAC cells in vitro. In vivo, in EAC patient tumors, expression of the glycolytic enzyme PKM2 is positively associated with obesity.

Aflibercept in Diabetic Macular Oedema Previously Refractory to Standard Intravitreal Therapy: An Irish Retrospective Study.

INTRODUCTION: To determine visual and anatomical outcomes of diabetic macular oedema (DMO) patients in a tertiary centre following conversion to aflibercept having been refractory to previous treatment with bevacizumab/ranibizumab. METHODS: A retrospective case series of patients with a diagnosis of DMO undergoing aflibercept intravitreal therapy for at least 6 months who had previous treatment with three consecutive bevacizumab/ranibizumab injections pre-switch. Exclusion criteria included other procedures affecting visual outcome performed within the treatment period. Outcomes measured included visual acuity (VA), central macular thickness (CMT) and injection frequency. RESULTS: Eighteen eyes of 13 patients were included. Mean VA pre-switch was 61.5 ± 13.8 letters and CMT was 433.2 ± 101.4. Mean number of prior bevacizumab/ranibizumab treatments was 11.3 ± 7.2. Mean follow-up post-switch was 22.5 months (SD 7.9). Mean VA improved from baseline by 4.8 letters at 6 months (p = 0.005), by 6.1 letters at 12 months (p = 0.006), by 7.9 letters (p = 0.004) at 18 months and by 6.4 letters (p = 0.1) at 24 months. Mean CMT decreased from baseline by 108.6 µm at 6 months (p = 0.01), 117.7 µm at 12 months (p = 0.0003), 158.0 µm at 18 months (p = 0.005) and by 123.3 µm at 24 months (p = 0.02). CONCLUSION: Switching to aflibercept in treatment-resistant DMO produces significant improvements in visual and anatomical outcomes, with eventual maintenance of VA levels.

Parallel Profiles of Inflammatory and Effector Memory T Cells in Visceral Fat and Liver of Obesity-Associated Cancer Patients.

In the midst of a worsening obesity epidemic, the incidence of obesity-associated morbidities, including cancer, diabetes, cardiac and liver disease is increasing. Insights into mechanisms underlying pathological obesity-associated inflammation are lacking. Both the omentum, the principal component of visceral fat, and liver of obese individuals are sites of excessive inflammation, but to date the T cell profiles of both compartments have not been assessed or compared in a patient cohort with obesity-associated disease. We have previously identified that omentum is enriched with inflammatory cytokines, chemokines and T cells. Here, we compared the inflammatory profile of T cells in the omentum and liver of patients with the obesity-associated malignancy oesophageal adenocarcinoma (OAC). Furthermore, we assessed the secreted cytokine profile in OAC patient serum, omentum and liver to assess systemic and local inflammation. We observed parallel T cell cytokine profiles and phenotypes in the omentum and liver of OAC patients, in particular CD69(+) and inflammatory effector memory T cells. This study reflects similar processes of inflammation and T cell activation in the omentum and liver, and may suggest common targets to modulate pathological inflammation at these sites.

Establishing computed tomography-defined visceral fat area thresholds for use in obesity-related cancer research.

Excess visceral adiposity is associated with increased gastrointestinal cancer risk. Evidence suggests that the systemic inflammation and dysmetabolism observed in visceral obesity underpins this association. Along with magnetic resonance imaging, computed tomography is a gold standard for abdominal fat quantification and is routinely available for gastrointestinal cancer research. However, no gender-specific cutoff values are currently available for classifying visceral obesity in white populations. Using the metabolic syndrome (MetSyn) as an indicator of obesity-associated dysmetabolism, this study aimed to establish pathologically relevant, gender-specific cut-off values for use in obesity-associated cancer research. Total, visceral and subcutaneous fat areas were calculated between the L3 and L4 invertebral space from computed tomography scans in a cohort of 170 males and 66 females undergoing gastrointestinal resection. Receiver operating characteristics analysis was used to determine cut-off values for total, visceral and subcutaneous fat areas associated with MetSyn. Linear regression was used to correlate these values with waist circumference. Visceral fat area (VFA) strongly correlated with the presence of MetSyn (P < .0001). The cut-off value for VFA associated with the presence of MetSyn was 163.8 cm(2) in males (83.6% sensitivity, 62.5% specificity) and 80.1 cm(2) for females (96% sensitivity, 73.2% specificity). The waist circumference corresponding to these VFA values was 96.1 cm in males and 83.2 cm in females. This study is the first to generate gender-specific and pathologically relevant cut-off values for VFA in patients with gastrointestinal cancer. In the field of obesity-associated research, this new anthropometric measure is of paramount importance for determining the accurate pathological obesity status of cancer patients.