Visceral adipose tissue secretome from early and late-stage oesophageal cancer patients differentially affects effector and regulatory T cells

AIM

Visceral obesity is a key risk factor in the development of oesophagogastric junctional adenocarcinoma (OGJ), predominantly via generation of systemic low grade inflammation. Obesity-induced inflammation promotes resistance to current standards of care, enhancing tumour cell growth and survival. This study investigates the effect of the visceral adipose tissue secretome from OGJ patients with early versus advanced tumours on T-cell immunity and the role of immune checkpoint blockade in enhancing anti-tumour immunity.

METHODS AND RESULTS

Visceral adipose conditioned media (ACM) from both early and late-stage OGJ patients significantly altered T cell activation status, upregulating co-stimulatory marker CD27 on T cells. ACM from both early and late-stage OGJ patients significantly altered immune checkpoint expression profiles downregulating immune checkpoints (ICs) on the surface of dual Th1/17-like and Th17-like cells and upregulating ICs on the surface of Th1-like cells and Treg cells. ACM derived from early-stage OGJ patients but not late-stage OGJ patients increased IFN-γ production by T cells. The addition of immune checkpoint blockers (ICBs) did not increase IFN-γ production by T cells in the presence of late-stage ACM, collectively highlighting the dichotomous immunostimulatory effect of early-stage ACM and immune-inhibitory effect of late-stage ACM. Interestingly, ACM from early-stage OGJ patients was more pro-inflammatory than ACM from late-stage patients, reflected by decreased levels of IL-17A/F, TNF-α, IL-1RA and IL-5.

CONCLUSION

The ACM-induced upregulation of ICs on T cells highlights a therapeutic vulnerability that could be exploited by ICBs to harness anti-cancer immunity and improve clinical outcomes for OGJ patients. Schematic workflow - (A) visceral adipose tissue was taken from OAC patients at time of surgery and cultured for 72 h in media. (B) The harvested ACM was co-cultured with healthy donor PBMCs that were concurrently activated with anti-CD3/28 for 48 h and T cell immunophenotyping was carried out by flow cytometry. Key findings - (A) Early and late stage ACM enhanced a Th1-like phenotype and upregulated CTLA-4 on Th1-like cells. A Th17-like phenotype was also enhanced in addition with a Treg-like phenotype. CTLA-4 and PD-L1 were upregulated on the surface of Treg-like cells. (B) ICB-attenuated IL-17 production by T cells. However, ACM attenuated ICB-mediated reduction in IL-10 production by T cells. Higher levels of pro-inflammatory factors were found in early stage ACM compared with late stage ACM.

Cooperation between chemotherapy and immune checkpoint blockade to enhance anti-tumour T cell immunity in oesophageal adenocarcinoma

Response rates to immune checkpoint blockade (ICB) remain low in oesophageal adenocarcinoma (OAC). Combining ICB with immunostimulatory chemotherapies to boost response rates is an attractive approach for converting 'cold' tumours into 'hot' tumours. This study profiled immune checkpoint (IC) expression on circulating and tumour-infiltrating T cells in OAC patients and correlated these findings with clinical characteristics. The effect of first-line chemotherapy regimens (FLOT and CROSS) on anti-tumour T cell immunity was assessed to help guide design of ICB and chemotherapy combinations in the first-line setting. The ability of ICB to enhance lymphocyte-mediated cytolysis of OAC cells in the absence and presence of post-FLOT and post-CROSS chemotherapy tumour cell secretome was assessed by a CCK-8 assay. Expression of ICs on T cells positively correlated with higher grade tumours and a subsequent poor response to neoadjuvant treatment. First-line chemotherapy regimens substantially altered IC expression profiles of T cells increasing PD-1, A2aR, KLRG-1, PD-L1, PD-L2 and CD160 and decreasing TIM-3 and LAG-3. In addition, pro-inflammatory T cell cytokine profiles were enhanced by first-line chemotherapy regimens. T cell activation status was significantly altered; both chemotherapy regimens upregulated co-stimulatory markers ICOS and CD69 yet downregulated co-stimulatory marker CD27. However, ICB attenuated chemotherapy-induced downregulation of CD27 on T cells and promoted differentiation of effector memory T cells into a terminally differentiated state. Importantly, dual nivolumab-ipilimumab treatment increased lymphocyte-mediated cytolysis of OAC cells, an effect further enhanced in the presence of post-FLOT tumour cell secretome. These findings justify a rationale to administer ICBs concurrently with first-line chemotherapies.

PD-1 and TIGIT blockade differentially affect tumour cell survival under hypoxia and glucose deprived conditions in oesophageal adenocarcinoma; implications for overcoming resistance to PD-1 blockade in hypoxic tumours

•

PD-1 and TIGIT expression are highly expressed on the surface of oesophageal epithelial cells during the early stages of metaplasia.

•

Glucose deprivation and hypoxia upregulate PD-1 and TIGIT on the surface of oesophageal adenocarcinoma (OAC) cells in vitro.

•

PD-1 and TIGIT blockade decrease Bcl-2 and Bcl-xL expression in OAC cells.

•

PD-1 blockade in OAC cells enhances basal respiration and glycolytic reserve and upregulates GLUT1 on the surface of a subpopulation of OAC cells.

•

PD-1 inhibition confers a survival advantage to OAC cells under glucose deprivation and hypoxia.

•

TIGIT blockade decreases OAC cell proliferation and induces OAC cell death under normoxia, hypoxia and nutrient deprivation.

•

TIGIT blockade increases ECAR yet decreases a range of metabolic parameters in OAC cells.

Recent studies have demontrated that immune checkpoint receptors are expressed on the surface of oesophageal adenocarcinoma (OAC) cells and might confer a survival advantage. This study explores the role of PD-1 and TIGIT signalling in OAC cells in either promoting or inhibiting the survival of OAC cells under characteristic features of the tumour microenvironment including nutrient-deprivation and hypoxia. PD-1 and TIGIT are expressed in normal and pre-malignant oesophageal epithelial cells and this expression significantly decreases along the normal- Barrett's Oesophagus- OAC disease sequence. However, glucose-deprivation and hypoxia significantly upregulated PD-1 and TIGIT on the surface of OAC cells in vitro. PD-1 blockade decreased OAC cell proliferation under normoxia but enhanced proliferation and decreased cell death in OAC cells under hypoxia and glucose-deprivation. TIGIT blockade decreased proliferation and induced OAC cell death, an effect that was maintained under nutrient-deprivation and hypoxia. Basal respiration and glycolytic reserve were enhanced and GLUT1 was upregulated on the surface of a subpopulation of OAC cells following PD-1 blockade. In contrast, TIGIT blockade enhanced a glycolytic phenotype in OAC cells, yet decreased other metabolic parameters including oxidative phosphorylation and basal respiration. Interestingly, inhibition of oxidative phosphorylation significantly upregulated TIGIT expression and inhibition of oxidative phosphorylation and glycolysis significantly decreased PD-1 on the surface of a subpopulation of OAC cells in vitro. These findings suggest an immune-independent mechanism for PD-1 inhibitor resistance in hypoxic tumours and suggest that TIGIT might be a more effective therapeutic target in OAC compared with PD-1 for treating hypoxic tumours.

Chemotherapy regimens induce inhibitory immune checkpoint protein expression on stem-like and senescent-like oesophageal adenocarcinoma cells

•

OAC cells express several inhibitory immune checkpoint (IC) ligands and receptors.

•

Chemotherapy upregulates IC ligands and receptors on the surface of OAC cells.

•

ICs are enriched on stem-like and senescent OAC cells following chemotherapy.

•

PD-1 blockade induced apoptosis and enhanced chemotherapy toxicity in OAC cells.

Use of immune checkpoint inhibitors (ICIs) with chemotherapy to enhance responses in oesophageal adenocarcinoma (OAC) is an attractive approach. We identified subpopulations of OAC cells expressing inhibitory immune checkpoint (IC) ligands (PD-L1, PD-L2 and CD160) and receptors (PD-1, TIGIT, TIM-3, LAG-3 and A2aR) in vitro and in ex vivo biopsies. Combination chemotherapy regimens FLOT and CROSS promote a more immune-resistant phenotype through upregulation of IC ligands and receptors on OAC cells in vitro. Importantly, this study investigated if OAC cells, enriched for ICs exhibited a more stem-like and senescent-like phentoype. FLOT preferentially upregulates PD-L1 on a stem-like OAC cell phenotype, defined by ALDH activity. Expression of senescence-associated β-galactosidase is induced in a subpopulation of OAC cells following FLOT and CROSS chemotherapy treatment, along with enhanced expression of TIM-3 and A2aR ICs. Blockade of PD-1 signalling in OAC cells induced apoptosis and enhanced FLOT and CROSS chemotherapy toxicity in vitro. Upregulation of ICs on OAC cells following chemotherapy may represent potential mechanisms of chemo-immune resistance. Combination ICIs may be required to enhance the efficacy of chemotherapy and immunotherapy in OAC patients.

Health literacy and the perception of risk in a breast cancer family history clinic

BACKGROUND

Informed consent is an essential component of medical practice, and especially so in procedural based specialties which entail varying degrees of risk. Breast cancer is one of the most common cancers in women, and as such is the focus of extensive research and significant media attention. Despite this, considerable misperception exists regarding the risk of developing breast cancer.

AIMS

This study aims to examine the accuracy of risk perception of women attending a breast cancer family history clinic, and to explore the relationship between risk perception accuracy and health literacy.

METHODS

A cross-sectional study of women attending a breast cancer family history clinic (n = 86) was carried out, consisting of a patient survey and a validated health literacy assessment. Patients' perception of personal and population breast cancer risk was compared to actual risk as calculated by a validated risk assessment tool.

RESULTS

Significant discordance between real and perceived risks was observed. The majority (83.7%) of women overestimated their personal lifetime risk of developing breast cancer, as well as that of other women of the same age (89.5%). Health literacy was considered potentially inadequate in 37.2% of patients; there was a correlation between low health literacy and increased risk perception inaccuracy across both personal ten-year (r_s = 0.224, p = 0.039) and general ten-year population estimations. (r_s = 0.267, p = 0.013).

CONCLUSION

Inaccuracy in risk perception is highly prevalent in women attending a breast cancer family history clinic. Health literacy inadequacy is significantly associated with this inaccuracy.

Smoking profile of non-consultant hospital doctors

BACKGROUND

In 1994 Doll and colleagues published smoking mortality figures for British doctors over 40 years.

AIMS

To assess smoking prevalence among junior doctors in a major Dublin teaching hospital.

METHODS

One hundred and fourteen non-consultant doctors (NCHDs) at St James's Hospital received a confidential smoking questionnaire.

RESULTS

One hundred and six NCHDs responded (93%). Three refused, five were not available. Ninety per cent were aged 24-35 years. Twenty-six per cent of the doctors had smoked for 10 to 15 years. Seventy-five per cent were smoking more than 10 cigarettes daily. Ninety-seven per cent (20) of smokers wanted to stop smoking. Seventy-four per cent (17) had unsuccessfully attempted to quit. The smoking cessation method most commonly used was'cold turkey' in 60%. Others included nicotine replacement, bupropion and hypnotherapy.

CONCLUSION

A significant per centage of NCHDs (22%) continue to smoke, despite overwhelming evidence that this causes health problems. The prevalence in our study is lower than the national figure of 29%.