Identification of neoantigens in oesophageal adenocarcinoma

Oesophageal adenocarcinoma (OAC) has a relatively poor long-term survival and limited treatment options. Promising targets for immunotherapy are short peptide neoantigens containing tumour mutations, presented to cytotoxic T-cells by human leucocyte antigen (HLA) molecules. Despite an association between putative neoantigen abundance and therapeutic response across cancers, immunogenic neoantigens are challenging to identify. Here we characterized the mutational and immunopeptidomic landscapes of tumours from a cohort of seven patients with OAC. We directly identified one HLA-I presented neoantigen from one patient, and report functional T-cell responses from a predicted HLA-II neoantigen in a second patient. The predicted class II neoantigen contains both HLA I and II binding motifs. Our exploratory observations are consistent with previous neoantigen studies in finding that neoantigens are rarely directly observed, and an identification success rate following prediction in the order of 10%. However, our identified putative neoantigen is capable of eliciting strong T-cell responses, emphasizing the need for improved strategies for neoantigen identification.

Operation Moonshot: rapid translation of a SARS-CoV-2 targeted peptide immunoaffinity liquid chromatography-tandem mass spectrometry test from research into routine clinical use

OBJECTIVES

During 2020, the UK's Department of Health and Social Care (DHSC) established the Moonshot programme to fund various diagnostic approaches for the detection of SARS-CoV-2, the pathogen behind the COVID-19 pandemic. Mass spectrometry was one of the technologies proposed to increase testing capacity.

METHODS

Moonshot funded a multi-phase development programme, bringing together experts from academia, industry and the NHS to develop a state-of-the-art targeted protein assay utilising enrichment and liquid chromatography tandem mass spectrometry (LC-MS/MS) to capture and detect low levels of tryptic peptides derived from SARS-CoV-2 virus. The assay relies on detection of target peptides, ADETQALPQRK (ADE) and AYNVTQAFGR (AYN), derived from the nucleocapsid protein of SARS-CoV-2, measurement of which allowed the specific, sensitive, and robust detection of the virus from nasopharyngeal (NP) swabs. The diagnostic sensitivity and specificity of LC-MS/MS was compared with reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) via a prospective study.

RESULTS

Analysis of NP swabs (n=361) with a median RT-qPCR quantification cycle (Cq) of 27 (range 16.7-39.1) demonstrated diagnostic sensitivity of 92.4% (87.4-95.5), specificity of 97.4% (94.0-98.9) and near total concordance with RT-qPCR (Cohen's Kappa 0.90). Excluding Cq>32 samples, sensitivity was 97.9% (94.1-99.3), specificity 97.4% (94.0-98.9) and Cohen's Kappa 0.95.

CONCLUSIONS

This unique collaboration between academia, industry and the NHS enabled development, translation, and validation of a SARS-CoV-2 method in NP swabs to be achieved in 5 months. This pilot provides a model and pipeline for future accelerated development and implementation of LC-MS/MS protein/peptide assays into the routine clinical laboratory.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

The differentiation state of the Schwann cell progenitor drives phenotypic variation between two contagious cancers

Contagious cancers are a rare pathogenic phenomenon in which cancer cells gain the ability to spread between genetically distinct hosts. Nine examples have been identified across marine bivalves, dogs and Tasmanian devils, but the Tasmanian devil is the only mammalian species known to have given rise to two distinct lineages of contagious cancer, termed Devil Facial Tumour 1 (DFT1) and 2 (DFT2). Remarkably, DFT1 and DFT2 arose independently from the same cell type, a Schwann cell, and while their ultra-structural features are highly similar they exhibit variation in their mutational signatures and infection dynamics. As such, DFT1 and DFT2 provide a unique framework for investigating how a common progenitor cell can give rise to distinct contagious cancers. Using a proteomics approach, we show that DFT1 and DFT2 are derived from Schwann cells in different differentiation states, with DFT2 carrying a molecular signature of a less well differentiated Schwann cell. Under inflammatory signals DFT1 and DFT2 have different gene expression profiles, most notably involving Schwann cell markers of differentiation, reflecting the influence of their distinct origins. Further, DFT2 cells express immune cell markers typically expressed during nerve repair, consistent with an ability to manipulate their extracellular environment, facilitating the cell’s ability to transmit between individuals. The emergence of two contagious cancers in the Tasmanian devil suggests that the inherent plasticity of Schwann cells confers a vulnerability to the formation of contagious cancers.

Cancer can be an infectious pathogen, with nine known cases, infecting bivalves, dogs and two independent tumours circulating in the endangered Tasmanian devil. These cancers, known as Devil Facial Tumour 1 (DFT1) and Devil Facial Tumour 2 (DFT2), spread through the wild population much like parasites, moving between genetically distinct hosts during social biting behaviours and persisting in the population. As DFT1 and DFT2 are independent contagious cancers that arose from the same cell type, a Schwann cell, they provide a unique model system for studying the emergence of phenotypic variation in cancers derived from a single progenitor cell. In this study, we have shown that these two remarkably similar tumours have emerged from Schwann cells in different differentiation states. The differentiation state of the progenitor has altered the characteristics of each tumour, resulting in different responses to external signals. This work demonstrates that the cellular origin of infection can direct the phenotype of a contagious cancer and how it responds to signals from the host environment. Further, the plasticity of Schwann cells may make these cells more prone to forming contagious cancers, raising the possibility that further parasitic cancers could emerge from this cell type.

Characterization of the Class I MHC Peptidome Resulting From DNCB Exposure of HaCaT Cells

Skin sensitization following the covalent modification of proteins by low molecular weight chemicals (haptenation) is mediated by cytotoxic T lymphocyte (CTL) recognition of human leukocyte antigen (HLA) molecules presented on the surface of almost all nucleated cells. There exist 3 nonmutually exclusive hypotheses for how haptens mediate CTL recognition: direct stimulation by haptenated peptides, hapten modification of HLA leading to an altered HLA-peptide repertoire, or a hapten altered proteome leading to an altered HLA-peptide repertoire. To shed light on the mechanism underpinning skin sensitization, we set out to utilize proteomic analysis of keratinocyte presented antigens following exposure to 2,4-dinitrochlorobenzene (DNCB). We show that the following DNCB exposure, cultured keratinocytes present cysteine haptenated (dinitrophenylated) peptides in multiple HLA molecules. In addition, we find that one of the DNCB modified peptides derives from the active site of cytosolic glutathione-S transferase-ω. These results support the current view that a key mechanism of skin sensitization is stimulation of CTLs by haptenated peptides. Data are available via ProteomeXchange with identifier PXD021373.

Real-world clinical profile, treatment patterns and patient-reported outcomes in a subset of HR+/HER2- advanced breast cancer patients with poor prognostic factors: data from an international study

Background

Patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2−) advanced breast cancer (ABC) and disease-related poor prognostic factors are not well characterized. We aimed to describe patient demographics, disease characteristics, treatment patterns and patient-reported outcomes in a subset of HR+/HER2− ABC patients with these factors [at the time when cyclin-dependent kinase (CDK) 4 and 6 inhibitors were being introduced] and understand how these factors informed treatment decisions at the time of the survey.

Methods

Real-world data were derived from a large, multinational, point-in-time survey of oncologists and their consulting patients with HR+/HER2− ABC in the EU5 and USA over March-June 2017, at the start of the changing treatment landscape. Analysis focused on four poor prognostic factors: visceral metastases, liver metastases (subset of visceral metastases), progesterone receptor-negative status and high tumor grade.

Results

In total, 2259 patients with HR+/HER2− ABC had records eligible for this analysis. At least one poor prognostic factor was present in 63% of patients (most common visceral metastases; least common progesterone receptor-negative status), with varying degrees of overlap between factors. For physician-reported outcomes, pain increased, whereas performance status and activities of daily living declined with presence of poor prognostic factors, especially liver metastases. No clear trends were observed for patient-reported outcomes. Treatment with combined endocrine therapy plus CDK4 and 6 inhibitors was infrequent, as these agents were entering the market.

Conclusions

More than 60% of the HR+/HER2− ABC Adelphi Real World Disease Specific Programme™ sample had ≥1 disease-related poor prognostic factor, and patients appeared to be heterogeneous regarding occurrence and distribution of these factors. These patients typically have increased pain and reduced performance status, highlighting the importance of implementing effective therapy with CDK4 and 6 inhibitors. Future studies could inform how the treatment landscape has evolved over time with respect to patients with poor prognostic factors.

•

Some 63% of HR+/HER2− ABC patients in this sample had ≥1 disease-related factors more likely to confer a poorer prognosis

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Patients with these factors typically had increased pain and reduced performance status

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Chemotherapy was prescribed more frequently in patients with poor prognostic factors

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Introduction of CDK4 and 6 inhibitors saw more patients with poor prognostic factors receive endocrine therapy-based regimens

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This study is a baseline to understand the impact of these new treatments on prognosis and aggressive disease

Race matters: cardiovascular disease risk in male US prisoners

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): NIH/National Institute of Nursing Research, 1RC2NR011948

Introduction

Approximately 10% of the 2.2 million prisoners in the US have a diagnosis of cardiovascular disease (CVD) and in 2016, 28% of all deaths in custody were attributable to CVD. Black race, inadequate health literacy, and poor perceived control are predictors of increased cardiovascular disease (CVD) risk, which are prevalent in prisoners. However, little is known about the relationships among race, health literacy, and perceived control in CVD risk for male prisoners.

Objective

The purpose of this study was to explore the relationships among race, health literacy, perceived control, and CVD risk while controlling for well-known risk factors (education, partner status, and body mass index) in male prisoners.

Methods

We used baseline data from 349 male prisoners in a biobehavioral CVD risk reduction intervention. Health literacy was measured using the Newest Vital Sign and perceived control by the Control Attitudes Scale- Revised. CVD risk was quantified with the Framingham Risk Score (FRS). Three indirect effects of race on CVD risk were examined using serial mediation model with two sequential mediators (i.e., health literacy and perceived control) and 95% confidence intervals from 5000 bootstrap samples.

Results

Of the participants (mean age = 36 + 10 years), 64.2% were white and 35.8% were black. Mean education level was 12 years and most (85.8%) were not married or partnered. Mean BMI was 28.3 + 5.0. Mean FRS was 6.63 + 4.90, indicating risk percentages of 2.3 to 13.3% over the next ten years. Black prisoners were younger (35 + 9 versus 37 + 10, p = .047) and had lower levels of health literacy (3.84 + 1.90 versus 4.69 + 1.63, p < .001) than white prisoners. No statistically significant differences in perceived control, education, partner status, or body mass index were noted between races. All three indirect effects of race on CVD were significant while the direct effect of race was not. Compared to white prisoners, black prisoners had higher levels of CVD risk through health literacy (a1b1 = .3571, 95% CI [.0948, .7162]) and lower levels of CVD risk through perceived control (a2b2 = -.1855, 95% CI [-.4388, -.0077]). Black prisoners had higher levels of CVD risk through health literacy influenced by perceived control (a1b2d21 = .0627, 95% CI [.0028, .1409]) indicating that despite the protective effect of higher levels of perceived control in black prisoners, CVD risk remained higher compared to their white counterparts.

Conclusion

Future CVD risk reduction interventions in prisoners of all races, but specifically black male prisoners, should include goals of improving health literacy and perceived control in addition to the traditional modifiable risk factors often included in biobehavioral interventions.

The immunopeptidomes of two transmissible cancers and their host have a common, dominant peptide motif

Transmissible cancers are malignant cells that can spread between individuals of a population, akin to both a parasite and a mobile graft. The survival of the Tasmanian devil, the largest remaining marsupial carnivore, is threatened by the remarkable emergence of two independent lineages of transmissible cancer, devil facial tumour (DFT) 1 and devil facial tumour 2 (DFT2). To aid the development of a vaccine and to interrogate how histocompatibility barriers can be overcome, we analysed the peptides bound to major histocompatibility complex class I (MHC‐I) molecules from Tasmanian devil cells and representative cell lines of each transmissible cancer. Here, we show that DFT1 + IFN‐γ and DFT2 cell lines express a restricted repertoire of MHC‐I allotypes compared with fibroblast cells, potentially reducing the breadth of peptide presentation. Comparison of the peptidomes from DFT1 + IFNγ, DFT2 and host fibroblast cells demonstrates a dominant motif, despite differences in MHC‐I allotypes between the cell lines, with preference for a hydrophobic leucine residue at position 3 and position Ω of peptides. DFT1 and DFT2 both present peptides derived from neural proteins, which reflects a shared cellular origin that could be exploited for vaccine design. These results suggest that polymorphisms in MHC‐I molecules between tumours and host can be ‘hidden’ by a common peptide motif, providing the potential for permissive passage of infectious cells and demonstrating complexity in mammalian histocompatibility barriers.

Objective and subjective rapid frailty screening tools in people with HIV

OBJECTIVES

As people with HIV (PWH) age, the prevalence of frailty increases. Rapid screening tests to identify frailty within HIV outpatient settings are required to identify at-risk individuals. We undertook a service evaluation to assess three short frailty assessments in PWH.

METHODS

We assessed two objective [gait speed (GS), timed-up-and-go test (TUGT)] and one subjective [the self-reported health questionnaire (SRH)] frailty screening tools in PWH aged > 40 years attending a single HIV outpatient department. Factors associated with positive frailty screening tests (defined as GS < 0.8 m/s, TUGT ≥ 10 s and SRH score < 6) were assessed using logistic regression models.

ETHICAL CONSIDERATIONS

This was a service evaluation and was approved as a service evaluation by the Imperial College Healthcare NHS trust HIV clinical research committee (February 2020). All participants were given verbal information and were able to terminate the screening tests at any time.

RESULTS

Of 84 PWH approached, 80 individuals completed all screening tests (median age = 56 years, range: 40-80) with a positive frailty screening prevalence in 19%, 33% and 20% for GS, TUGT and SRH, respectively. All tests were considered acceptable to participants. Factors statistically significantly associated with frailty included age (GS and TUGT), detectable HIV RNA (TUGT), number of comorbidities (GS and TUGT), presence of polypharmacy (GS and TUGT) and total number of concomitant medication (GS and SRH).

CONCLUSIONS

Rates of positive screening tests for frailty are dependent on screening tool used, with all three tools being acceptable to participants. Objective measures of frailty screening (GS and TUGT) are more closely associated with clinical parameters than is a subjective measure of frailty screening (SRH).

Society of pediatric liver transplantation: Current registry status 2011-2018

BACKGROUND

SPLIT was founded in 1995 in order to collect comprehensive prospective data on pediatric liver transplantation, including waiting list data, transplant, and early and late outcomes. Since 2011, data collection of the current registry has been refined to focus on prospective data and outcomes only after transplant to serve as a foundation for the future development of targeted clinical studies.

OBJECTIVE

To report the outcomes of the SPLIT registry from 2011 to 2018.

METHODS

This is a multicenter, cross-sectional analysis characterizing patients transplanted and enrolled in the SPLIT registry between 2011 and 2018. All patients, <18 years of age, received a first liver-only, a combined liver-kidney, or a combined liver-pancreas transplant during this study period.

RESULTS

A total of 1911 recipients from 39 participating centers in North America were registered. Indications included biliary atresia (38.5%), metabolic disease (19.1%), tumors (11.7%), and fulminant liver failure (11.5%). Greater than 50% of recipients were transplanted as either Status 1A/1B or with a MELD/PELD exception score. Incompatible transplants were performed in 4.1%. Kaplan-Meier estimates of 1-year patient and graft survival were 97.3% and 96.6%. First 30 days of surgical complications included reoperation (31.7%), hepatic artery thrombosis (6.3%), and portal vein thrombosis (3.2%). In the first 90 days, biliary tract complications were reported in 13.6%. Acute cellular rejection during first year was 34.7%. At 1 and 2 years of follow-up, 39.2% and 50.6% had normal liver tests on monotherapy (tacrolimus or sirolimus). Further surgical, survival, allograft function, and complications are detailed.

Oxytocin reduces post-stress sweet snack intake in women without attenuating salivary cortisol

Intranasal oxytocin produces anorectic effects on snack intake in men when tested in the absence of deprivation-induced hunger, but its effects on food intake in women without eating disorders have not been reported. Oxytocin may reduce food intake by reducing stress eating, since it inhibits ACTH release. The present study adopted a double-blind, repeated measures and fully concealed crossover protocol in which 38 women self-administered 24 IU of oxytocin or placebo intranasally, ate lunch, and underwent two consecutive stress tests. Snack intake was assessed 15-20 min after lunch, via a sham taste test. Salivary cortisol was measured throughout the test period every 15 min. Oxytocin significantly reduced sweet fatty snack intake independently of any effect on salivary cortisol, which declined over time at a similar rate after either drug or placebo. Ratings of sweet taste were slightly reduced by oxytocin, but only in self-reported stress eaters. These results differ from previous studies with men that found an effect of oxytocin on postprandial cortisol levels. However, previous research assayed the less active form of plasma cortisol and did not control for protein intake, which can drive elevated cortisol. The finding that oxytocin reduces snack intake in females after acute stress has important implications for appetite regulation and its treatment in obese people and in those with eating disorders.

P14.30 Treatment outcomes of newly-diagnosed glioblastoma multiforme (GBM) by O6-methylguanine DNA methyltransferase promoter (MGMT) status: a multi-country study

INTRODUCTION

This study evaluated the relationship of MGMT status with first-line (1L) treatment outcomes of patients with newly-diagnosed GBM in France, Germany, Italy, Spain, the UK (EU5), and Canada.

MATERIALS AND METHODS

Medical oncologists and neuro-oncologists across EU5 and Canada completed a point in time, cross-sectional survey for the next 8 GBM patients seen between May and July 2016 within EU5 and Canada. All results apart from time to progression (TTP) were presented for patients receiving 1L active drug treatment. TTP was calculated from initiation of 1L treatment to initiation of second-line treatment. Results presented are statistically significant (p<0.05) unless otherwise specified. Bases vary depending on data availability.

RESULTS

A total of 241 physicians reported on 1747 patients with GBM. 875 were receiving 1L active drug treatment at time of survey. Mean age was 59.7 years (median=61) and 34.6% were women. Mean life expectancy was 14.9 months (median=12) at diagnosis and mean TTP was 8.5 months (median=7.3). Surgery was performed in 62% of patients (n=546) prior to 1L drug treatment; 38% of patients (n=329) had no surgery. Patients with surgery had a higher life expectancy at diagnosis vs patients with no surgery prior to 1L (mean=16.4 vs 12.2 months; median=15.0 vs 12.0). Patients who received corticosteroids (n=524) vs no corticosteroids during radiotherapy (n=64) had a shorter life expectancy at diagnosis (mean=15.0 vs 16.8 months, p=0.07; median=12.5 vs 13.9) and were more likely to have 8 or more inpatient days due to GBM (21% vs 8%, p=0.07) in the last 3 months prior to the survey. 62% of patients (n=541) had an MGMT-status recorded (tested: methylated or unmethylated), and 38% (n=334) were untested/ awaiting results (untested) at 1L. MGMT-tested patients had better life expectancy at diagnosis (mean=16.1 vs 12.9 months; median=15.0 vs 12.0) and longer TTP (mean=8.9 vs 7.8 months; median=7.8 vs 6.4) than untested patients. Among MGMT-tested patients, 58% were methylated and 42% were unmethylated. Methylated patients had similar life expectancy at diagnosis (mean=15.9 vs 16.3 months, p=0.85; median=15.0 vs 15.0) and TTP (mean=9.0 vs 8.8 months, p=0.42; median=8.0 vs 7.5) as unmethylated patients.

CONCLUSIONS

This analysis provides valuable insights into the 1L treatment outcomes of GBM patients in EU5 and Canada. Patients who did not undergo surgery had worse treatment outcomes. Steroid use appears to be associated with worse outcomes and higher healthcare resource utilization. Patient treatment outcomes varied depending on whether they are MGMT tested.

P14.36 Treatment patterns by O6-methylguanine DNA methyltransferase promoter (MGMT) status in newly-diagnosed glioblastoma multiforme (GBM): a multi-country chart review study

INTRODUCTION

This study explored the relationship between MGMT testing and treatment patterns of patients with newly-diagnosed GBM from France, Germany, Italy, Spain, the UK (EU5), and Canada.

MATERIALS AND METHODS

Medical oncologists and neuro-oncologists across EU5 and Canada completed a point in time, cross-sectional survey for the next eight GBM patients seen between May and July 2016 (GBM Disease-specific ProgrammeTM). Statistically significant differences (p<0.05) between groups are presented.

RESULTS

A total of 241 physicians reported on 1,747 GBM patients. 1L patients had mean age 59.7 years (SD=12.3) and 36% were female. Of 1,113 (64%) patients who had an MGMT test performed with results recorded (tested), 58% (n=651) were methylated and 42% (n=462) were unmethylated. The remaining 634 patients (36%) were MGMT untested or awaiting MGMT results at time of survey (untested). Overall, 63% of patients received surgery prior to their 1L drug therapy, 78% received radiotherapy (RT; mean 4.3 sessions) in conjunction with 1L drug therapy, 90% received corticosteroids during RT, and 89% received temozolomide (TMZ). Patients who received corticosteroids during RT received similar drug treatments to those that did not, but were less likely to receive surgery prior to 1L treatment (65% vs 83%). MGMT-tested patients were more likely to receive surgery (66% vs 57%) and RT (81% vs 71%) than untested patients. Tested patients were also more likely to receive TMZ (92% vs 83%), and less likely to receive procarbazine+/lomustine+/vincristine (PCV; 3% vs 7%) or other chemotherapies (5% vs 11%). For 1L patients that experienced side effects, the most common effects included fatigue (74%), nausea (60%), and appetite loss (59%). Untested patients were more likely to stop their 1L drug treatment due to progression/recurrence of GBM (44% vs 36%). Patients who received surgery prior to 1L treatment were more likely to receive TMZ than those who did not (93% vs 82%). Among MGMT tested patients at 1L, methylated patients were more likely to receive RT (84% vs 78%) and TMZ (95% vs 89%) than unmethylated patients, and less likely to receive PCV (2% vs 5%) or other chemotherapy (4% vs 7%). Methylated patients with reported treatment-related side effects were less likely to experience dehydration (0% vs 10%), loss of strength/unusual weakness (5% vs 25%), memory problems (16% vs 35%), and nausea (51% vs 75%).

CONCLUSIONS

More than one-third of GBM patients in EU5 and Canada are not tested for MGMT-methylation. Untested patients are less likely to receive standard treatments than tested patients. Generally, TMZ is used in most patients regardless of MGMT testing and status. MGMT-methylated patients are more likely to receive standard treatments and experience fewer side effects than MGMT-unmethylated patients.

Dynamically Driven Allostery in MHC Proteins: Peptide-Dependent Tuning of Class I MHC Global Flexibility

T cell receptor (TCR) recognition of antigenic peptides bound and presented by class I major histocompatibility complex (MHC) proteins underlies the cytotoxic immune response to diseased cells. Crystallographic structures of TCR-peptide/MHC complexes have demonstrated how TCRs simultaneously interact with both the peptide and the MHC protein. However, it is increasingly recognized that, beyond serving as a static platform for peptide presentation, the physical properties of class I MHC proteins are tuned by different peptides in ways that are not always structurally visible. These include MHC protein motions, or dynamics, which are believed to influence interactions with a variety of MHC-binding proteins, including not only TCRs, but other activating and inhibitory receptors as well as components of the peptide loading machinery. Here, we investigated the mechanisms by which peptides tune the dynamics of the common class I MHC protein HLA-A2. By examining more than 50 lengthy molecular dynamics simulations of HLA-A2 presenting different peptides, we identified regions susceptible to dynamic tuning, including regions in the peptide binding domain as well as the distal α3 domain. Further analyses of the simulations illuminated mechanisms by which the influences of different peptides are communicated throughout the protein, and involve regions of the peptide binding groove, the β₂-microglobulin subunit, and the α3 domain. Overall, our results demonstrate that the class I MHC protein is a highly tunable peptide sensor whose physical properties vary considerably with bound peptide. Our data provides insight into the underlying principles and suggest a role for dynamically driven allostery in the immunological function of MHC proteins.

Abstract OT3-05-02: ALEXANDRA/IMpassion030: A phase III study of standard adjuvant chemotherapy with or without atezolizumab in early triple negative breast cancer

Background: Triple negative breast cancer (TNBC) is a subtype with a high risk of relapse in the early disease setting. Because TNBC does not currently have specific targeted agents approved for use in the early setting it is treated primarily with chemotherapy. A growing body of evidence indicates that TNBC is more immunogenic than other subtypes of breast cancer and promising clinical activity has been reported with atezolizumab (an anti–PD-L1 antibody) in Phase 1/1b metastatic TNBC trials. Furthermore, the anti-tumor activity of PD-1/PD-L1 targeting drugs is hypothesized to be enhanced when co-administered with chemotherapy. ALEXANDRA/IMpassion030 will evaluate the efficacy and safety of atezolizumab in combination with standard adjuvant chemotherapy in early TNBC.

Methods: ALEXANDRA/IMpassion030 is a global, prospective, randomised, open-label Phase 3 trial investigating the efficacy, safety and pharmacokinetic (PK) profile of adjuvant atezolizumab plus standard chemotherapy versus chemotherapy alone in early TNBC. In total, 2300 patients diagnosed with non-metastatic operable stage II or III TNBC confirmed by central pathology review will be randomised. TumorPD-L1evaluationwill be performed centrally. Patients will be stratified by type of surgery, nodal status, and PD-L1 status. The adjuvant treatment will consist of weekly paclitaxel 80 mg/m2 for 12 weeks followed by dose dense anthracycline (epirubicin 90 mg/m2 or doxorubicin 60 mg/m2) and cyclophosphamide 600 mg/m2 for 4 doses every 2 weeks or the same chemotherapy regimen (T-EC/AC) given concomitantly with atezolizumab 840 mg every 2 weeks followed by maintenance atezolizumab 1200 mg every 3 weeks until completion of 1 year of atezolizumab. Primary end-point is invasive disease-free survival (iDFS) and secondary end-points include iDFS by PD-L1 and lymph node status, overall survival, safety, patient functioning and health related quality of life (HRQoL). Tumour tissue and blood samples will be collected for biomarker research. The first site was activated in May 4th, and approximately 430 sites are expected to be open globally in 30 countries. This trial is sponsored by Roche and conducted in partnership with the Breast International Group, Frontier Science and Technology Research Foundation, Institute Jules Bordet and Alliance Foundation Trials. Clinicaltrials.gov NCT03498716.

Citation Format: Ignatiadis M, McArthur H, Bailey A, Martinez J-L, De Azambuja E, Metzger O, Lai C, Ponde N, Goulioti T, Daly F, Bouhlel A, Balta V, Van Dooren V, Viale G, Maetens M, Dufrane C, Nguyen Duc A, Winer E, Gelber R, Piccart M. ALEXANDRA/IMpassion030: A phase III study of standard adjuvant chemotherapy with or without atezolizumab in early triple negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT3-05-02.

Phosphorylation-deficient G-protein-biased μ-opioid receptors improve analgesia and diminish tolerance but worsen opioid side effects

Opioid analgesics are powerful pain relievers; however, over time, pain control diminishes as analgesic tolerance develops. The molecular mechanisms initiating tolerance have remained unresolved to date. We have previously shown that desensitization of the μ-opioid receptor and interaction with β-arrestins is controlled by carboxyl-terminal phosphorylation. Here we created knockin mice with a series of serine- and threonine-to-alanine mutations that render the receptor increasingly unable to recruit β-arrestins. Desensitization is inhibited in locus coeruleus neurons of mutant mice. Opioid-induced analgesia is strongly enhanced and analgesic tolerance is greatly diminished. Surprisingly, respiratory depression, constipation, and opioid withdrawal signs are unchanged or exacerbated, indicating that β-arrestin recruitment does not contribute to the severity of opioid side effects and, hence, predicting that G-protein-biased µ-agonists are still likely to elicit severe adverse effects. In conclusion, our findings identify carboxyl-terminal multisite phosphorylation as key step that drives acute μ-opioid receptor desensitization and long-term tolerance.

Nicotinic receptors mediate stress-nicotine detrimental interplay via dopamine cells' activity

Epidemiological studies report strong association between mood disorders and tobacco addiction. This high comorbidity requires adequate treatment but the underlying mechanisms are unknown. We demonstrate that nicotine exposure, independent of drug withdrawal effects, increases stress sensitivity, a major risk factor in mood disorders. Nicotine and stress concur to induce long-lasting cellular adaptations within the dopamine (DA) system. This interplay is underpinned by marked remodeling of nicotinic systems, causing increased ventral tegmental area (VTA) DA neurons' activity and stress-related behaviors, such as social aversion. Blocking β2 or α7 nicotinic acetylcholine receptors (nAChRs) prevents, respectively, the development and the expression of social stress-induced neuroadaptations; conversely, facilitating α7 nAChRs activation specifically in the VTA promotes stress-induced cellular and behavioral maladaptations. Our work unravels a complex nicotine-stress bidirectional interplay and identifies α7 nAChRs as a promising therapeutic target for stress-related psychiatric disorders.

Direct evidence for conformational dynamics in major histocompatibility complex class I molecules

Major histocompatibility complex class I molecules (MHC I) help protect jawed vertebrates by binding and presenting immunogenic peptides to cytotoxic T lymphocytes. Peptides are selected from a large diversity present in the endoplasmic reticulum. However, only a limited number of peptides complement the polymorphic MHC specificity determining pockets in a way that leads to high-affinity peptide binding and efficient antigen presentation. MHC I molecules possess an intrinsic ability to discriminate between peptides, which varies in efficiency between allotypes, but the mechanism of selection is unknown. Elucidation of the selection mechanism is likely to benefit future immune-modulatory therapies. Evidence suggests peptide selection involves transient adoption of alternative, presumably higher energy conformations than native peptide-MHC complexes. However, the instability of peptide-receptive MHC molecules has hindered characterization of such conformational plasticity. To investigate the dynamic nature of MHC, we refolded MHC proteins with peptides that can be hydrolyzed by UV light and thus released. We compared the resultant peptide-receptive MHC molecules with non-hydrolyzed peptide-loaded MHC complexes by monitoring the exchange of hydrogen for deuterium in solution. We found differences in hydrogen-deuterium exchange between peptide-loaded and peptide-receptive molecules that were negated by the addition of peptide to peptide-receptive MHC molecules. Peptide hydrolysis caused significant increases in hydrogen-deuterium exchange in sub-regions of the peptide-binding domain and smaller increases elsewhere, including in the α3 domain and the non-covalently associated β2-microglobulin molecule, demonstrating long-range dynamic communication. Comparing two MHC allotypes revealed allotype-specific differences in hydrogen-deuterium exchange, consistent with the notion that MHC I plasticity underpins peptide selection.

Development of a roof bolter canopy air curtain for respirable dust control

Testing of the roof bolter canopy air curtain (CAC) designed by the U.S. National Institute for Occupational Safety and Health (NIOSH) has gone through many iterations, demonstrating successful dust control performance under controlled laboratory conditions. J.H. Fletcher & Co., an original equipment manufacturer of mining equipment, further developed the concept by incorporating it into the design of its roof bolting machines. In the present work, laboratory testing was conducted, showing dust control efficiencies ranging from 17.2 to 24.5 percent. Subsequent computational fluid dynamics (CFD) analysis revealed limitations in the design, and a potential improvement was analyzed and recommended. As a result, a new CAC design is being developed, incorporating the results of the testing and CFD analysis.

Recent advances in Major Histocompatibility Complex (MHC) class I antigen presentation: Plastic MHC molecules and TAPBPR-mediated quality control

We have known since the late 1980s that the function of classical major histocompatibility complex (MHC) class I molecules is to bind peptides and display them at the cell surface to cytotoxic T cells. Recognition by these sentinels of the immune system can lead to the destruction of the presenting cell, thus protecting the host from pathogens and cancer. Classical MHC class I molecules (MHC I hereafter) are co-dominantly expressed, polygenic, and exceptionally polymorphic and have significant sequence diversity. Thus, in most species, there are many different MHC I allotypes expressed, each with different peptide-binding specificity, which can have a dramatic effect on disease outcome. Although MHC allotypes vary in their primary sequence, they share common tertiary and quaternary structures. Here, we review the evidence that, despite this commonality, polymorphic amino acid differences between allotypes alter the ability of MHC I molecules to change shape (that is, their conformational plasticity). We discuss how the peptide loading co-factor tapasin might modify this plasticity to augment peptide loading. Lastly, we consider recent findings concerning the functions of the non-classical MHC I molecule HLA-E as well as the tapasin-related protein TAPBPR (transporter associated with antigen presentation binding protein-related), which has been shown to act as a second quality-control stage in MHC I antigen presentation.

Treatment-limiting renal tubulopathy in patients treated with tenofovir disoproxil fumarate

OBJECTIVES

Tenofovir disoproxil fumarate (TDF) is widely used in the treatment or prevention of HIV and hepatitis B infection. TDF may cause renal tubulopathy in a small proportion of recipients. We aimed to study the risk factors for developing severe renal tubulopathy.

METHODS

We conducted an observational cohort study with retrospective identification of cases of treatment-limiting tubulopathy during TDF exposure. We used multivariate Poisson regression analysis to identify risk factors for tubulopathy, and mixed effects models to analyse adjusted estimated glomerular filtration rate (eGFR) slopes.

RESULTS

Between October 2002 and June 2013, 60 (0.4%) of 15,983 patients who had received TDF developed tubulopathy after a median exposure of 44.1 (IQR 20.4, 64.4) months. Tubulopathy cases were predominantly male (92%), of white ethnicity (93%), and exposed to antiretroviral regimens that contained boosted protease inhibitors (PI, 90%). In multivariate analysis, age, ethnicity, CD4 cell count and use of didanosine or PI were significantly associated with tubulopathy. Tubulopathy cases experienced significantly greater eGFR decline while receiving TDF than the comparator group (-6.60 [-7.70, -5.50] vs. -0.34 [-0.43, -0.26] mL/min/1.73 m²/year, p < 0.0001).

CONCLUSIONS

Older age, white ethnicity, immunodeficiency and co-administration of ddI and PI were risk factors for tubulopathy in patients who received TDF-containing antiretroviral therapy. The presence of rapid eGFR decline identified TDF recipients at increased risk of tubulopathy.

The Role of Charcoal Ash Content in the Performance of Air Purification Filters

A nutshell-based activated carbon was treated with hydrochloric acid to partially de-ash it. The de-ashed sample was then treated with bromine water and subsequently hydrogenated. The base sample was also treated with bromine water and then hydrogenated. The surface areas and pore volumes available to water vapour were unchanged by these treatments, although the polar surface area was considerably reduced in each case. The sample with the lowest surface polarity had the worst performance (shortest penetration time) when pre-humidified at 80% RH and tested with hexane. Examination of the humidity leaving the bed during the adsorption of hexane vapour suggested that the rate-determining step was the surface transport of displaced water and that removing the ash content hindered this transport considerably. Bromination followed by hydrogenation, although reducing the polarity, did not remove the ash content and may even have improved its ability to transport displaced water.

Adaptors and Innovators: Selection versus Induction

The hypothesis that predictable differences would exist between the mean cognitive style of new entrants and those of the longer serving “established” employees in certain departments while not in others was tested. Data from 99 employees from four departments of a large British pharmaceuticals company who completed the Kirton Adaption-Innovation Inventory provided results broadly in line with the expectations of adaption-innovation theory and past research. The mean innovative cognitive style of new entrants to adaptive departments regressed towards the mean of the establishment and the occupational mean over time. In departments where there was no initial significant difference between the mean cognitive style of the new entrants and the established group, no significant shift was shown over time. Implications of these findings are suggested. The data also indicated norms for two occupational groups where previously they did not exist.

The Role of Mesoporosity in the Transport of Displaced Water during the Adsorption of Benzene by Prehumidified Charcoal Filters

Active carbons have been characterised by nitrogen adsorption isotherms and mercury intrusion. Penetration tests with benzene vapour have been made on carbon filters in dry and humid conditions. The filter efficiency under humid conditions was found to be greater for carbons having a greater number of meso- and small macro-pores (2–100 nm). The effect is probably related to the storage and transport of displaced water in the carbon filter bed.

A Novel Approach for Determining the Position of Primary Water-Adsorbing Centres within the Porous Structure of Active Carbons

A novel application of adsorption isotherms has been developed to determine the position of the primary water-adsorbing centres within the porous structure of active carbons. Naphthalene was pre-adsorbed to partially fill the micropores. The number of primary adsorption centres was determined by application of the Langmuir and modified Dubinin–Serpinsky equations to water isotherm data measured on the pretreated carbons.

Abstract P6-12-08: Healthcare barrier profiles in patients navigated for cancer screening and treatment and the impact of the affordable care act

Background: The underserved community experiences barriers to cancer screening that result in overall greater mortality rates across all cancers. Insurance coverage brought forth by the Affordable Care Act has the potential to significantly impact these barriers through reducing the burden of health care cost on the patient. In this study the authors observe the impact of the Affordable Care Act on the barrier profiles presented by the patients navigated for cancer screening and treatment.

Methods: Patient navigation encounters were recorded for a total of 1146 patients navigated for cancer screening and treatment at the Cleveland Clinic Foundation from the years 2012 through 2015. A total of 3259 encounters were classified into barrier types. Health care billed encounters were retrieved from EPIC for this group of patients from the time they entered patient navigation and classified in terms of insurance coverage. Patients were categorized according to their barrier profile. Appropriate generalized linear regression models were used to test for association of these profiles to number and types of navigation and health care encounters and cost, and to test for change in types of encounters and patient barrier profiles through time.

Results: The insurance barrier is present in 23% of all navigation encounters. Patients presenting with an insurance barrier had a greater mean number of navigation (p&lt;0.001) and health care encounters (p&lt;0.006), had a greater proportion of self-paid health care encounters (p&lt;0.001) and a lower total cost billed for health care encounters after controlling for number of encounters (p&lt;0.001) . The access barrier is present in 53% of navigation encounters while patients that present with only the access barrier account for 42% of the entire sample. Patients that present with only the access barrier have doubled every year (OR 2.2 per year, 95% CI [1.8 2.6]) from 2012 to 2015, while the proportion of self-paid health care encounters (OR 0.26 per year, 95% CI [0.25 0.28]) and the presence of the insurance barrier (OR 0.55 per year, 95% CI [ 0.49 0.62]) have more than halved during this time period.

Conclusion: Although the Affordable Care Act has clearly had an impact by lowering the number of insurance barrier navigation encounters through time, it has uncovered access as the predominant remaining barrier. Understanding and targeting the access barrier will be the most effective way to potentiate the effects of the ACA on patients being navigated for cancer screening and treatment.

Citation Format: Raska P, Ott MA, Steele A, Bailey A, Hickman D, Allen D, Urbanek D, Glass K, Bailey J, Bell K, Montero A, Abraham J. Healthcare barrier profiles in patients navigated for cancer screening and treatment and the impact of the affordable care act. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-12-08.

Plasticity of empty major histocompatibility complex class I molecules determines peptide-selector function

Major histocompatibility complex class I (MHC I) proteins provide protection from intracellular pathogens and cancer via each of a cell's MHC I molecules binding and presenting a peptide to cytotoxic T lymphocytes. MHC I genes are highly polymorphic and can have significant diversity, with polymorphisms predominantly localised in the peptide-binding groove where they can change peptide-binding specificity. However, polymorphic residues may also determine other functional properties, such as how dependent MHC I alleles are on the peptide-loading complex for optimal acquisition of peptide cargo. We describe how differences in the peptide-binding properties of two MHC I alleles correlates with altered conformational flexibility in the peptide-empty state. We hypothesise that plasticity is an intrinsic property encoded by the protein sequence, and that co-ordinated movements of the membrane-proximal and membrane-distal domains collectively determines how dependent MHC I are on the peptide-loading complex for efficient assembly with high affinity peptides.

Selector function of MHC I molecules is determined by protein plasticity

The selection of peptides for presentation at the surface of most nucleated cells by major histocompatibility complex class I molecules (MHC I) is crucial to the immune response in vertebrates. However, the mechanisms of the rapid selection of high affinity peptides by MHC I from amongst thousands of mostly low affinity peptides are not well understood. We developed computational systems models encoding distinct mechanistic hypotheses for two molecules, HLA-B*44:02 (B*4402) and HLA-B*44:05 (B*4405), which differ by a single residue yet lie at opposite ends of the spectrum in their intrinsic ability to select high affinity peptides. We used in vivo biochemical data to infer that a conformational intermediate of MHC I is significant for peptide selection. We used molecular dynamics simulations to show that peptide selector function correlates with protein plasticity, and confirmed this experimentally by altering the plasticity of MHC I with a single point mutation, which altered in vivo selector function in a predictable way. Finally, we investigated the mechanisms by which the co-factor tapasin influences MHC I plasticity. We propose that tapasin modulates MHC I plasticity by dynamically coupling the peptide binding region and α3 domain of MHC I allosterically, resulting in enhanced peptide selector function.

Allergens on desktop surfaces in preschools and elementary schools of urban children with asthma

Desktop dust has been studied as a source of food allergen, but not as a source of potential aeroallergen exposure. Thirty-six wiped samples from desktop surfaces were collected from preschools and schools. Samples were analyzed for detectable levels of common aeroallergens including Alternaria, cockroach, dog, dust mite, cat, mouse, and rat allergens by immunoassay. Mouse allergen was the most prevalent, detectable in 97.2% of samples. Cat allergen was detectable in 80.6% of samples, and dog allergen was detectable in 77.8% of samples. Other allergens were not as prevalent. Mouse was the only allergen that was highly correlated with settled floor dust collected from the same rooms (r = 0.721, P < 0.001). This is the first study to detect aeroallergens on desktop surfaces by using moist wipes. Allergens for mouse, cat, and dog were highly detectable in wipes with mouse desktop surface levels correlating with levels in vacuumed floor dust.