Analysing the Combined Effects of Radiotherapy and Chemokine Receptor 5 Antagonism: Complementary Approaches to Promote T Cell Function and Migration in Oesophageal Adenocarcinoma.

The presence of an immunosuppressive tumour microenvironment in oesophageal adenocarcinoma (OAC) is a major contributor to poor responses. Novel treatment strategies are required to supplement current regimens and improve patient survival. This study examined the immunomodulatory effects that radiation therapy and chemokine receptor antagonism impose on T cell phenotypes in OAC with a primary goal of identifying potential therapeutic targets to combine with radiation to improve anti-tumour responses. Compared with healthy controls, anti-tumour T cell function was impaired in OAC patients, demonstrated by lower IFN-γ production by CD4+ T helper cells and lower CD8+ T cell cytotoxic potential. Such diminished T cell effector functions were enhanced following treatment with clinically relevant doses of irradiation. Interestingly, CCR5+ T cells were significantly more abundant in OAC patient blood compared with healthy controls, and CCR5 surface expression by T cells was further enhanced by clinically relevant doses of irradiation. Moreover, irradiation enhanced T cell migration towards OAC patient-derived tumour-conditioned media (TCM). In vitro treatment with the CCR5 antagonist Maraviroc enhanced IFN-γ production by CD4+ T cells and increased the migration of irradiated CD8+ T cells towards irradiated TCM, suggesting its synergistic therapeutic potential in combination with irradiation. Overall, this study highlights the immunostimulatory properties of radiation in promoting anti-tumour T cell responses in OAC and increasing T cell migration towards chemotactic cues in the tumour. Importantly, the CCR5 antagonist Maraviroc holds promise to be repurposed in combination with radiotherapy to promote anti-tumour T cell responses in OAC.

A Pilot Study of Adolescents with Psychotic Experiences: Potential Cerebellar Circuitry Disruption Early Along the Psychosis Spectrum.

A berrant connectivity in the cerebellum has been found in psychotic conditions such as schizophrenia corresponding with cognitive and motor deficits found in these conditions. Diffusion differences in the superior cerebellar peduncles, the white matter connecting the cerebellar circuitry to the rest of the brain, have also been found in schizophrenia and high-risk states. However, white matter diffusivity in the peduncles in individuals with sub-threshold psychotic experiences (PEs) but not reaching the threshold for a definitive diagnosis remains unstudied. This study investigates the cerebellar peduncles in adolescents with PEs but no formal psychiatric diagnosis.Sixteen adolescents with PEs and 17 age-matched controls recruited from schools underwent High-Angular-Resolution-Diffusion neuroimaging. Following constrained spherical deconvolution whole-brain tractography, the superior, inferior and middle peduncles were isolated and virtually dissected out using ExploreDTI. Differences for macroscopic and microscopic tract metrics were calculated using one-way between-group analyses of covariance controlling for age, sex and estimated Total Intracranial Volume (eTIV). Multiple comparisons were corrected using Bonferroni correction.A decrease in fractional anisotropy was identified in the right (p = 0.045) and left (p = 0.058) superior cerebellar peduncle; however, this did not survive strict Bonferroni multiple comparison correction. There were no differences in volumes or other diffusion metrics in either the middle or inferior peduncles.Our trend level changes in the superior cerebellar peduncle in a non-clinical sample exhibiting psychotic experiences complement similar but more profound changes previously found in ultra-high-risk individuals and those with psychotic disorders. This suggests that superior cerebellar peduncle circuitry perturbations may occur early along in the psychosis spectrum.

PD-1 blockade attenuates surgery-mediated immunosuppression and boosts Th1 immunity perioperatively in oesophagogastric junctional adenocarcinoma.

Introduction: This timely study assesses the immunosuppressive effects of surgery on cytotoxic Th1-like immunity and investigates if immune checkpoint blockade (ICB) can boost Th1-like immunity in the perioperative window in upper gastrointestinal cancer (UGI) patients. Methods: PBMCs were isolated from 11 UGI patients undergoing tumour resection on post-operative days (POD) 0, 1, 7 and 42 and expanded ex vivo using anti-CD3/28 and IL-2 for 5 days in the absence/presence of nivolumab or ipilimumab. T cells were subsequently immunophenotyped via flow cytometry to determine the frequency of T helper (Th)1-like, Th1/17-like, Th17-like and regulatory T cell (Tregs) subsets and their immune checkpoint expression profile. Lymphocyte secretions were also assessed via multiplex ELISA (IFN-γ, granzyme B, IL-17 and IL-10). The 48h cytotoxic ability of vehicle-, nivolumab- and ipilimumab-expanded PBMCs isolated on POD 0, 1, 7 and 42 against radiosensitive and radioresistant oesophageal adenocarcinoma tumour cells (OE33 P and OE33 R) was also examined using a cell counting kit-8 (CCK-8) assay to determine if surgery affected the killing ability of lymphocytes and whether the use of ICB could enhance cytotoxicity. Results: Th1-like immunity was suppressed in expanded PBMCs in the immediate post-operative setting. The frequency of expanded circulating Th1-like cells was significantly decreased post-operatively accompanied by a decrease in IFN-γ production and a concomitant increase in the frequency of expanded regulatory T cells with an increase in circulating levels of IL-10. Interestingly, PD-L1 and CTLA-4 immune checkpoint proteins were also upregulated on expanded Th1-like cells post-operatively. Additionally, the cytotoxic ability of expanded lymphocytes against oesophageal adenocarcinoma tumour cells was abrogated post-surgery. Of note, the addition of nivolumab or ipilimumab attenuated the surgery-mediated suppression of lymphocyte cytotoxicity, demonstrated by a significant increase in tumour cell killing and an increase in the frequency of Th1-like cells and Th1 cytokine production. Conclusion: These findings support the hypothesis of a surgery-mediated suppression in Th1-like cytotoxic immunity and highlights a rationale for the use of ICB within the perioperative setting to abrogate tumour-promoting effects of surgery and ameliorate the risk of recurrence.

Acidosis significantly alters immune checkpoint expression profiles of T cells from oesophageal adenocarcinoma patients.

Tumour acidosis contributes to cancer progression by inhibiting anti-tumour immunity. However, the effect of acidosis on anti-tumour T cell phenotypes in oesophageal adenocarcinoma (OAC) is unknown. Therefore, this study investigated the effect of acidosis on anti-tumour T cell profiles and if immune checkpoint blockade (ICB) could enhance anti-tumour T cell immunity under acidosis. Acidic conditions substantially altered immune checkpoint expression profiles of OAC patient-derived T cells, upregulating TIM-3, LAG-3 and CTLA-4. Severe acidosis (pH 5.5) significantly decreased the percentage of central memory CD4+ T cells, an effect that was attenuated by ICB treatment. ICB increased T cell production of IFN-γ under moderate acidosis (pH 6.6) but not severe acidosis (pH 5.5) and decreased IL-10 production by T cells under severe acidic conditions only. A link between lactate and metastasis was also depicted; patients with nodal metastasis had higher serum lactate levels (p = 0.07) which also positively correlated with circulating levels of pro-angiogenic factor Tie-2. Our findings establish that acidosis-induced upregulation of immune checkpoints on T cells may potentially contribute to immune evasion and disease progression in OAC. However, acidic conditions curtailed ICB efficacy, supporting a rationale for utilizing systemic oral buffers to neutralize tumour acidity to improve ICB efficacy. Study schematic-PBMCs were isolated from OAC patients (A) and expanded ex vivo for 7 days using anti-CD3/28 +IL-2 T cell activation protocol (B) and further cultured for 48 h under increasing acidic conditions in the absence or presence of immune checkpoint blockade (nivolumab, ipilimumab or dual nivolumab + ipilimumab) (C). Immunophenotyping was then carried out to assess immune checkpoint expression profiles and anti-tumour T cell phenotypes (D). Serum lactate was assessed in OAC patients (E-F) and levels were correlated with patient demographics (G) and the levels of circulating immune/pro-angiogenic cytokines that were determined by multiplex ELISA (H). Key Findings-severe acidic conditions upregulated multiple immune checkpoints on T cells (I). Efficacy of ICB was curtailed under severe acidic conditions (J). Circulating lactate levels positively correlated with circulating levels of pro-angiogenic factor tie-2 and higher serum lactate levels were found in patients who had nodal metastasis (K).

Nutrient deprivation and hypoxia alter T cell immune checkpoint expression: potential impact for immunotherapy.

AIM: Use of immune checkpoint blockade to enhance T cell-mediated immunity within the hostile tumour microenvironment (TME) is an attractive approach in oesophageal adenocarcinoma (OAC). This study explored the effects of the hostile TME, including nutrient deprivation and hypoxia, on immune checkpoint (IC) expression and T cell phenotypes, and the potential use of nivolumab to enhance T cell function under such conditions. METHODS AND RESULTS: ICs were upregulated on stromal immune cells within the tumour including PD-L2, CTLA-4 and TIGIT. OAC patient-derived PBMCs co-cultured with OE33 OAC cells upregulated LAG-3 and downregulated the co-stimulatory marker CD27 on T cells, highlighting the direct immunosuppressive effects of tumour cells on T cells. Hypoxia and nutrient deprivation altered the secretome of OAC patient-derived PBMCs, which induced upregulation of PD-L1 and PD-L2 on OE33 OAC cells thus enhancing an immune-resistant phenotype. Importantly, culturing OAC patient-derived PBMCs under dual hypoxia and glucose deprivation, reflective of the conditions within the hostile TME, upregulated an array of ICs on the surface of T cells including PD-1, CTLA-4, A2aR, PD-L1 and PD-L2 and decreased expression of IFN-γ by T cells. Addition of nivolumab under these hostile conditions decreased the production of pro-tumorigenic cytokine IL-10. CONCLUSION: Collectively, these findings highlight the immunosuppressive crosstalk between tumour cells and T cells within the OAC TME. The ability of nivolumab to suppress pro-tumorigenic T cell phenotypes within the hostile TME supports a rationale for the use of immune checkpoint blockade to promote anti-tumour immunity in OAC. Study schematic: (A) IC expression profiles were assessed on CD45+ cells in peripheral whole blood and infiltrating tumour tissue from OAC patients in the treatment-naïve setting. (B) PBMCs were isolated from OAC patients and expanded ex vivo for 5 days using anti-CD3/28 + IL-2 T cell activation protocol and then co-cultured for 48 h with OE33 cells. T cell phenotypes were then assessed by flow cytometry. (C) PBMCs were isolated from OAC patients and expanded ex vivo for 5 days using anti-CD3/28 + IL-2 T cell activation protocol and then further cultured under conditions of nutrient deprivation or hypoxia for 48 h and T cell phenotypes were then assessed by flow cytometry. KEY FINDINGS: (A) TIGIT, CTLA-4 and PD-L2 were upregulated on CD45+ immune cells and CTLA-4 expression on CD45+ cells correlated with a subsequent decreased response to neoadjuvant regimen. (B) Following a 48 h co-culture with OE33 cells, T cells upregulated LAG-3 and decreased CD27 co-stimulatory marker. (C) Nutrient deprivation and hypoxia upregulated a range of ICs on T cells and decreased IFN-γ production by T cells. Nivolumab decreased IL-10 production by T cells under nutrient deprivation-hypoxic conditions.

MRI volumetric changes in hippocampal subfields in psychosis: a protocol for a systematic review and meta-analysis.

BACKGROUND: The hippocampus has for long been known for its ability to form new, declarative memory. However, emerging findings across conditions in the psychosis spectrum also implicate its role in emotional regulation. Systematic reviews have demonstrated consistent volume atrophic changes in the hippocampus. The aim of the systematic review and metanalysis which will follow from this protocol will be to investigate the volume-based neuroimaging findings across each of the subfields of the hippocampus in psychosis independent of diagnosis. METHODS: Volume changes across subfields of the hippocampus in psychotic illnesses will be assessed by systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). MRI neuroimaging studies of patients with a definitive diagnosis of psychosis (including brief pre-diagnostic states) will be included. Studies lacking adequate controls, illicit drug use, medical psychosis, history of other significant psychiatric comorbidities, or emphasis on age groups above 65 or below 16 will be excluded. Subfields investigated will include the CA1, CA2/3, CA4, subiculum, presubiculum, parasubiculum, dentate gyrus, stratum, molecular layer, granular cell layer, entorhinal cortex, and fimbria. Two people will independently screen abstracts from the output of the search to select suitable studies. This will be followed by the two reviewers performing a full-text review of the studies which were selected based on suitable abstracts. One reviewer will independently perform all the data extraction, and another reviewer will then systemically check all the extracted information using the original articles to ensure accuracy. Statistical analysis will be performed using the metafor and meta-packages in R Studio with the application of the random-effects model. DISCUSSION: This study will provide insight into the volumetric changes in psychosis of the subfields of the hippocampus, independent of diagnosis. This may shed light on the intricate neural pathology which encompasses psychosis and will open avenues for further exploration of the structures identified as potential drivers of volume change. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42020199558.