Multi-Omic Analysis of Esophageal Adenocarcinoma Uncovers Candidate Therapeutic Targets and Cancer-Selective Posttranscriptional Regulation.

Efforts to address the poor prognosis associated with esophageal adenocarcinoma (EAC) have been hampered by a lack of biomarkers to identify early disease and therapeutic targets. Despite extensive efforts to understand the somatic mutations associated with EAC over the past decade, a gap remains in understanding how the atlas of genomic aberrations in this cancer impacts the proteome and which somatic variants are of importance for the disease phenotype. We performed a quantitative proteomic analysis of 23 EACs and matched adjacent normal esophageal and gastric tissues. We explored the correlation of transcript and protein abundance using tissue-matched RNA-seq and proteomic data from seven patients and further integrated these data with a cohort of EAC RNA-seq data (n = 264 patients), EAC whole-genome sequencing (n = 454 patients), and external published datasets. We quantified protein expression from 5879 genes in EAC and patient-matched normal tissues. Several biomarker candidates with EAC-selective expression were identified, including the transmembrane protein GPA33. We further verified the EAC-enriched expression of GPA33 in an external cohort of 115 patients and confirm this as an attractive diagnostic and therapeutic target. To further extend the insights gained from our proteomic data, an integrated analysis of protein and RNA expression in EAC and normal tissues revealed several genes with poorly correlated protein and RNA abundance, suggesting posttranscriptional regulation of protein expression. These outlier genes, including SLC25A30, TAOK2, and AGMAT, only rarely demonstrated somatic mutation, suggesting post-transcriptional drivers for this EAC-specific phenotype. AGMAT was demonstrated to be overexpressed at the protein level in EAC compared to adjacent normal tissues with an EAC-selective, post-transcriptional mechanism of regulation of protein abundance proposed. Integrated analysis of proteome, transcriptome, and genome in EAC has revealed several genes with tumor-selective, posttranscriptional regulation of protein expression, which may be an exploitable vulnerability.

Impact of early enteral feed composition on the rate of chyle leak post-esophagectomy.

Patients undergoing esophagectomy are at risk of malnutrition and benefit from perioperative enteral feeding. Esophagectomy carries a risk of chyle leak, and this risk may be influenced by early enteral feed composition. We evaluated the impact of early enteral medium-chain triglyceride-rich feed on the prevalence and severity of chyle leak post-esophagectomy, length of stay, and postoperative weight change. This retrospective study included consecutive patients undergoing esophagectomy at a single center between January 2015 and December 2022. Patients received enteral feed on postoperative days 1-5 with Nutrison Energy or Protein Plus Energy ('standard') (January 2015- June 2021) or Nutrison Peptisorb Plus High Energy High Protein ('HEHP') enteral feed (June 2021 to December 2022). All patients transitioned to 'standard' supplemental jejunal feeding on postoperative day 6 onwards and were discharged on oral IDDSI level 4 diet. Patients who did not commence early enteral feeding were excluded from analysis. A total of 329 patients were included. Patients who received early HEHP feed had fewer chyle leaks (5/52; 9.6%) compared with patients who received standard feed (68/277; 24.5%, P = 0.017). The HEHP group had a shorter total length of hospital stay (P = 0.011). Weight change from preoperative baseline was equivalent in both groups at 6 weeks (P = 0.066) and 3 months (P = 0.400). In the context of routine jejunostomy use and early enteral feeding post-esophagectomy, HEHP feed on postoperative days 1-5 was associated with significantly fewer chyle leaks and shorter length of stay compared with standard feed. No difference was noted in postoperative weight change between groups.

A Systematic Review on Clinical and Health-Related Quality of Life Outcomes following Total Gastrectomy in Patients with Hereditary Diffuse Gastric Cancer.

Hereditary diffuse gastric cancer (HDGC) is an autosomal-dominant syndrome associated with early onset diffuse gastric cancer. Definitive treatment is prophylactic total gastrectomy (PTG) associated with significant morbidity. Studies published from January 2000 to December 2022 reporting clinical, histopathological or health-related quality of life outcomes in HDGC patients undergoing PTG were identified. The study quality was assessed by the "Newcastle-Ottawa scale". Of the 257 articles screened, 21 were selected. A total of 353 patients were examined in 15 studies that reported surgical outcomes. The median age was 42 years old. The median major complication and mortality rates were 19.2% and 0.3%, respectively. The most common complications were wound infection at 4.8% followed by anastomotic leak and pulmonary complications at 4.5% each. Following PTG, 88.6% of patients had early lesions amongst 414 patients. The mean/median number of signet ring cell carcinoma foci in the gastrectomy specimens was from 2 to 78. All cases were stage 1 with no lymph node involvement. There was a wide range of psychosocial effects following PTG closely related to the physical symptoms. It is imperative for patients to receive comprehensive preoperative counselling to make an informed decision and be followed up under the care of a multidisciplinary team.

Risk-reducing surgery for individuals with cancer-predisposing germline pathogenic variants and no personal cancer history: a review of current UK guidelines.

Identifying healthy carriers of germline pathogenic variants in high penetrance cancer susceptibility genes offers the potential for risk-reducing surgery. The NHS England National Genomic Test Directory offers germline and somatic testing to patients with certain cancers or rare and inherited diseases, or, in some cases, to their relatives. This review summarises current UK guidelines for risk-reducing surgical interventions available for individuals with no personal history of cancer, who are determined to carry germline pathogenic variants. An electronic literature search of NICE guidelines and PubMed citable articles was performed. NICE guidelines are available for bilateral mastectomy and are currently in development for risk-reducing bilateral salpingo-oophorectomy. Guidelines developed with affiliation to, or through relevant British Surgical Societies or international consensus, are available for risk-reducing hysterectomy, polypectomy, gastrectomy, and thyroidectomy. There is a disparity in the development and distribution of national guidelines for interventions amongst tumour types. Whilst we are focusing on UK guidelines, we anticipate they will be relevant much more generally and so of interest to a wider audience including where there are no national guidelines to refer to. We suggest that, as genetic testing becomes rapidly more accessible, guideline development for interventions should be more closely aligned to those for testing.

The Immunopeptidome from a Genomic Perspective: Establishing the Noncanonical Landscape of MHC Class I-Associated Peptides.

Tumor antigens can emerge through multiple mechanisms, including translation of noncoding genomic regions. This noncanonical category of tumor antigens has recently gained attention; however, our understanding of how they recur within and between cancer types is still in its infancy. Therefore, we developed a proteogenomic pipeline based on deep learning de novo mass spectrometry (MS) to enable the discovery of noncanonical MHC class I-associated peptides (ncMAP) from noncoding regions. Considering that the emergence of tumor antigens can also involve posttranslational modifications (PTM), we included an open search component in our pipeline. Leveraging the wealth of MS-based immunopeptidomics, we analyzed data from 26 MHC class I immunopeptidomic studies across 11 different cancer types. We validated the de novo identified ncMAPs, along with the most abundant PTMs, using spectral matching and controlled their FDR to 1%. The noncanonical presentation appeared to be 5 times enriched for the A03 HLA supertype, with a projected population coverage of 55%. The data reveal an atlas of 8,601 ncMAPs with varying levels of cancer selectivity and suggest 17 cancer-selective ncMAPs as attractive therapeutic targets according to a stringent cutoff. In summary, the combination of the open-source pipeline and the atlas of ncMAPs reported herein could facilitate the identification and screening of ncMAPs as targets for T-cell therapies or vaccine development.

Systematic review and meta-analysis comparing perioperative outcomes of emergency appendectomy performed by trainee vs trained surgeon.

BACKGROUND: Appendectomy is a benchmark operation for trainee progression, but this should be weighed against patient safety and perioperative outcomes. METHODS: Systematic literature review and meta-analysis comparing outcomes of appendectomy performed by trainees versus trained surgeons. RESULTS: Of 2086 articles screened, 29 studies reporting on 135,358 participants were analyzed. There was no difference in mortality (Odds ratio [OR] 1.08, P = 0.830), overall complications (OR 0.93, P = 0.51), or major complications (OR 0.56, P = 0.16). There was no difference in conversion from laparoscopic to open surgery (OR 0.81, P = 0.12) and in intraoperative blood loss (Mean Difference [MD] 5.58 mL, P = 0.25). Trainees had longer operating time (MD 7.61 min, P < 0.0001). Appendectomy by trainees resulted in shorter duration of hospital stay (MD 0.16 days, P = 0.005) and decreased reoperation rate (OR 0.78, P = 0.05). CONCLUSIONS: Appendectomy performed by trainees does not compromise patient safety. Due to statistical heterogeneity, further randomized controlled trials, with standardized reported outcomes, are required.

Systematic review and meta-analysis comparing perioperative outcomes of pediatric emergency appendicectomy performed by trainee vs trained surgeon.

Appendicectomy is a common pediatric surgical procedure performed by trainees and surgeons with varying reported outcomes. It is a benchmark procedure for trainee progression and training benefits should be weighed against patient safety and perioperative outcomes. This systematic review and meta-analysis investigated any differential perioperative outcomes dependent on the grade of the operating surgeon. A systematic literature review and meta-analysis were performed comparing outcomes of pediatric appendicectomy performed by trainees versus trained surgeons. Of 2,086 articles screened, 5 retrospective non-randomized comparative studies reporting on 10,019 participants were analyzed. There was no difference in overall complications (OR 0.92; 95% CI 0.76, 1.12; P = 0.42), major complications [Clavien-Dindo (CD) III/IV] (OR 1.18; 95% CI 0.71, 1.97; P = 0.52), minor complications (CD I/II) (OR 1.13; 95% CI 0.57, 2.27; P = 0.72), post-op ileus (OR 0.74; 95% CI 0.10, 5.26; P = 0.76), wound infections (OR 0.87; 95% CI 0.62, 1.21; P = 0.41), abscess formation (OR 0.58; 95% CI 0.28, 1.22; P = 0.15), operation times [Mean Difference (MD) 2.31 min; 95% CI - 4.94, 9.56; P = 0.53] and reoperation rate (OR 1.22; 95% CI 0.23, 6.42; P = 0.81). Trainees had fewer conversions to open appendicectomy (OR 0.14; 95% CI 0.02, 0.88; P = 0.04). Appendicectomy performed on pediatric patients by trainees did not compromise patient safety. LEVEL OF EVIDENCE: III.

Multiparametric High-Content Cell Painting Identifies Copper Ionophores as Selective Modulators of Esophageal Cancer Phenotypes.

Esophageal adenocarcinoma is of increasing global concern due to increasing incidence, a lack of effective treatments, and poor prognosis. Therapeutic target discovery and clinical trials have been hindered by the heterogeneity of the disease, the lack of "druggable" driver mutations, and the dominance of large-scale genomic rearrangements. We have previously undertaken a comprehensive small-molecule phenotypic screen using the high-content Cell Painting assay to quantify the morphological response to a total of 19,555 small molecules across a panel of genetically distinct human esophageal cell lines to identify new therapeutic targets and small molecules for the treatment of esophageal adenocarcinoma. In this current study, we report for the first time the dose-response validation studies for the 72 screening hits from the target-annotated LOPAC and Prestwick FDA-approved compound libraries and the full list of 51 validated esophageal adenocarcinoma-selective small molecules (71% validation rate). We then focus on the most potent and selective hit molecules, elesclomol, disulfiram, and ammonium pyrrolidinedithiocarbamate. Using a multipronged, multitechnology approach, we uncover a unified mechanism of action and a vulnerability in esophageal adenocarcinoma toward copper-dependent cell death that could be targeted in the future.

A comparison of transhepatic versus transperitoneal cholecystostomy for acute calculous cholecystitis: a 5-year experience.

Percutaneous cholecystostomy is a treatment for acute calculous cholecystitis used in patients where surgery is high risk or challenging either to allow for surgical optimisation or as definitive treatment. In this case series we compare the outcomes of a transhepatic versus transperitoneal approach in patients undergoing percutaneous cholecystostomy for acute calculous cholecystitis. A retrospective review of patients from 2014 to 2019 was conducted and included demographics, percutaneous cholecystostomy route, complications and outcome. Fifty-one patients were included. Percutaneous cholecystostomy was placed transhepatically in 15 cases; transperitoneal in 30 cases; 6 cases had undetermined route. The transhepatic cohort had 43.5% fewer readmissions due to biliary sepsis, 32.5% fewer drain-related complications, and were less likely to require further treatment (32.5% reduction) compared to the transperitoneal cohort. In our experience, the transhepatic route is preferred due to fewer complications, fewer readmissions and a reduction in the need for further treatment.

Risk Prediction Model of 90-Day Mortality After Esophagectomy for Cancer.

Importance: Ninety-day mortality rates after esophagectomy are an indicator of the quality of surgical oncologic management. Accurate risk prediction based on large data sets may aid patients and surgeons in making informed decisions. Objective: To develop and validate a risk prediction model of death within 90 days after esophagectomy for cancer using the International Esodata Study Group (IESG) database, the largest existing prospective, multicenter cohort reporting standardized postoperative outcomes. Design, Setting, and Participants: In this diagnostic/prognostic study, we performed a retrospective analysis of patients from 39 institutions in 19 countries between January 1, 2015, and December 31, 2019. Patients with esophageal cancer were randomly assigned to development and validation cohorts. A scoring system that predicted death within 90 days based on logistic regression ß coefficients was conducted. A final prognostic score was determined and categorized into homogeneous risk groups that predicted death within 90 days. Calibration and discrimination tests were assessed between cohorts. Exposures: Esophageal resection for cancer of the esophagus and gastroesophageal junction. Main Outcomes and Measures: All-cause postoperative 90-day mortality. Results: A total of 8403 patients (mean [SD] age, 63.6 [9.0] years; 6641 [79.0%] male) were included. The 30-day mortality rate was 2.0% (n = 164), and the 90-day mortality rate was 4.2% (n = 353). Development (n = 4172) and validation (n = 4231) cohorts were randomly assigned. The multiple logistic regression model identified 10 weighted point variables factored into the prognostic score: age, sex, body mass index, performance status, myocardial infarction, connective tissue disease, peripheral vascular disease, liver disease, neoadjuvant treatment, and hospital volume. The prognostic scores were categorized into 5 risk groups: very low risk (score, ≥1; 90-day mortality, 1.8%), low risk (score, 0; 90-day mortality, 3.0%), medium risk (score, -1 to -2; 90-day mortality, 5.8%), high risk (score, -3 to -4: 90-day mortality, 8.9%), and very high risk (score, ≤-5; 90-day mortality, 18.2%). The model was supported by nonsignificance in the Hosmer-Lemeshow test. The discrimination (area under the receiver operating characteristic curve) was 0.68 (95% CI, 0.64-0.72) in the development cohort and 0.64 (95% CI, 0.60-0.69) in the validation cohort. Conclusions and Relevance: In this study, on the basis of preoperative variables, the IESG risk prediction model allowed stratification of an individual patient's risk of death within 90 days after esophagectomy. These data suggest that this model can help in the decision-making process when esophageal cancer surgery is being considered and in informed consent.

An integrated DNA and RNA variant detector identifies a highly conserved three base exon in the MAP4K5 kinase locus.

RNA variants that emerge from editing and alternative splicing form important regulatory stages in protein signalling. In this report, we apply an integrated DNA and RNA variant detection workbench to define the range of RNA variants that deviate from the reference genome in a human melanoma cell model. The RNA variants can be grouped into (i) classic ADAR-like or APOBEC-like RNA editing events and (ii) multiple-nucleotide variants (MNVs) including three and six base pair in-frame non-canonical unmapped exons. We focus on validating representative genes of these classes. First, clustered non-synonymous RNA edits (A-I) in the CDK13 gene were validated by Sanger sequencing to confirm the integrity of the RNA variant detection workbench. Second, a highly conserved RNA variant in the MAP4K5 gene was detected that results most likely from the splicing of a non-canonical three-base exon. The two RNA variants produced from the MAP4K5 locus deviate from the genomic reference sequence and produce V569E or V569del isoform variants. Low doses of splicing inhibitors demonstrated that the MAP4K5-V569E variant emerges from an SF3B1-dependent splicing event. Mass spectrometry of the recombinant SBP-tagged MAP4K5V569E and MAP4K5V569del proteins pull-downs in transfected cell systems was used to identify the protein-protein interactions of these two MAP4K5 isoforms and propose possible functions. Together these data highlight the utility of this integrated DNA and RNA variant detection platform to detect RNA variants in cancer cells and support future analysis of RNA variant detection in cancer tissue.

MicroPOTS Analysis of Barrett's Esophageal Cell Line Models Identifies Proteomic Changes after Physiologic and Radiation Stress.

Moving from macroscale preparative systems in proteomics to micro- and nanotechnologies offers researchers the ability to deeply profile smaller numbers of cells that are more likely to be encountered in clinical settings. Herein a recently developed microscale proteomic method, microdroplet processing in one pot for trace samples (microPOTS), was employed to identify proteomic changes in ∼200 Barrett's esophageal cells following physiologic and radiation stress exposure. From this small population of cells, microPOTS confidently identified >1500 protein groups, and achieved a high reproducibility with a Pearson's correlation coefficient value of R > 0.9 and over 50% protein overlap from replicates. A Barrett's cell line model treated with either lithocholic acid (LCA) or X-ray had 21 (e.g., ASNS, RALY, FAM120A, UBE2M, IDH1, ESD) and 32 (e.g., GLUL, CALU, SH3BGRL3, S100A9, FKBP3, AGR2) overexpressed proteins, respectively, compared to the untreated set. These results demonstrate the ability of microPOTS to routinely identify and quantify differentially expressed proteins from limited numbers of cells.

The effects of p53 gene inactivation on mutant proteome expression in a human melanoma cell model.

BACKGROUND: The identification of mutated proteins in human cancer cells-termed proteogenomics, requires several technologically independent research methodologies including DNA variant identification, RNA sequencing, and mass spectrometry. Any one of these methodologies are not optimized for identifying potential mutated proteins and any one output fails to cover completely a specific landscape. METHODS: An isogenic melanoma cell with a p53-null genotype was created by CRISPR/CAS9 system to determine how p53 gene inactivation affects mutant proteome expression. A mutant peptide reference database was developed by comparing two distinct DNA and RNA variant detection platforms using these isogenic cells. Chemically fractionated tryptic peptides from lysates were processed using a TripleTOF 5600+ mass spectrometer and their spectra were identified against this mutant reference database. RESULTS: Approximately 190 mutated peptides were enriched in wt-p53 cells, 187 mutant peptides were enriched in p53-null cells, with an overlap of 147 mutated peptides. STRING analysis highlighted that the wt-p53 cell line was enriched for mutant protein pathways such as CDC5L and POLR1B, whilst the p53-null cell line was enriched for mutated proteins comprising EGF/YES, Ubiquitination, and RPL26/5 nodes. CONCLUSION: Our study produces a well annotated p53-dependent and p53-independent mutant proteome of a common melanoma cell line model. Coupled to the application of an integrated DNA and RNA variant detection platform (CLCbio) and software for identification of proteins (ProteinPilot), this pipeline can be used to detect high confident mutant proteins in cells. GENERAL SIGNIFICANCE: This pipeline forms a blueprint for identifying mutated proteins in diseased cell systems.

High-Content Phenotypic Profiling in Esophageal Adenocarcinoma Identifies Selectively Active Pharmacological Classes of Drugs for Repurposing and Chemical Starting Points for Novel Drug Discovery.

Esophageal adenocarcinoma (EAC) is a highly heterogeneous disease, dominated by large-scale genomic rearrangements and copy number alterations. Such characteristics have hampered conventional target-directed drug discovery and personalized medicine strategies, contributing to poor outcomes for patients. We describe the application of a high-content Cell Painting assay to profile the phenotypic response of 19,555 compounds across a panel of six EAC cell lines and two tissue-matched control lines. We built an automated high-content image analysis pipeline to identify compounds that selectively modified the phenotype of EAC cell lines. We further trained a machine-learning model to predict the mechanism of action of EAC selective compounds using phenotypic fingerprints from a library of reference compounds. We identified a number of phenotypic clusters enriched with similar pharmacological classes, including methotrexate and three other antimetabolites that are highly selective for EAC cell lines. We further identify a small number of hits from our diverse chemical library that show potent and selective activity for EAC cell lines and that do not cluster with the reference library of compounds, indicating they may be selectively targeting novel esophageal cancer biology. Overall, our results demonstrate that our EAC phenotypic screening platform can identify existing pharmacologic classes and novel compounds with selective activity for EAC cell phenotypes.

An Overview of Mass Spectrometry-Based Methods for Functional Proteomics.

The mechanism underlying many biological phenotypes remains unknown despite the increasing availability of whole genome and transcriptome sequencing. Direct measurement of changes in protein expression is an attractive alternative and has the potential to reveal novel processes. Mass spectrometry has become the standard method for proteomics, allowing both the confident identification and quantification of thousands of proteins from biological samples. In this review, mass spectrometry-based proteomic methods and their applications are described.

The Sequence-specific Peptide-binding Activity of the Protein Sulfide Isomerase AGR2 Directs Its Stable Binding to the Oncogenic Receptor EpCAM.

AGR2 is an oncogenic endoplasmic reticulum (ER)-resident protein disulfide isomerase. AGR2 protein has a relatively unique property for a chaperone in that it can bind sequence-specifically to a specific peptide motif (TTIYY). A synthetic TTIYY-containing peptide column was used to affinity-purify AGR2 from crude lysates highlighting peptide selectivity in complex mixtures. Hydrogen-deuterium exchange mass spectrometry localized the dominant region in AGR2 that interacts with the TTIYY peptide to within a structural loop from amino acids 131-135 (VDPSL). A peptide binding site consensus of Tx[IL][YF][YF] was developed for AGR2 by measuring its activity against a mutant peptide library. Screening the human proteome for proteins harboring this motif revealed an enrichment in transmembrane proteins and we focused on validating EpCAM as a potential AGR2-interacting protein. AGR2 and EpCAM proteins formed a dose-dependent protein-protein interaction in vitro Proximity ligation assays demonstrated that endogenous AGR2 and EpCAM protein associate in cells. Introducing a single alanine mutation in EpCAM at Tyr251 attenuated its binding to AGR2 in vitro and in cells. Hydrogen-deuterium exchange mass spectrometry was used to identify a stable binding site for AGR2 on EpCAM, adjacent to the TLIYY motif and surrounding EpCAM's detergent binding site. These data define a dominant site on AGR2 that mediates its specific peptide-binding function. EpCAM forms a model client protein for AGR2 to study how an ER-resident chaperone can dock specifically to a peptide motif and regulate the trafficking a protein destined for the secretory pathway.

Patients unfit for neoadjuvant therapy may still undergo resection of locally advanced esophageal or esophagogastric junctional cancer with acceptable oncological results.

Neoadjuvant chemotherapy (NA) is routinely offered to patients undergoing resection for locally advanced (≥cT3Nx or cTxN+) esophageal or esophagogastric junctional (EGJ) cancer in the United Kingdom. Patients with comorbidity precluding the use of NA can be considered for resection yet the effect of omitting NA on survival is unclear. METHODS: Retrospective review of prospectively collected clinical data from patients undergoing attempted curative therapy for ≥cT3Nx or cTxN+ esophageal or EGJ (Siewert type I-III) cancer between 2001 and 2013. RESULTS: NA was commenced in 289 patients and primarily comprised 2 cycles of cisplatin and 5-fluorouracil (264 patients, 91%). Surgery alone was planned for 82 patients with NA omitted due to comorbidity. Patients undergoing surgery alone were matched for clinical variables and stage with those undergoing NA but were significantly older (mean=8 y, P<0.001). NA was associated with an improved median overall survival of 28.7 months, compared with 20.9 months for patients undergoing surgery alone (P=0.008). Patients undergoing surgery alone had a 90-day postoperative mortality rate of 10% compared with 3% for those undergoing NA (P=0.011). In patients discharged postoperatively, the median overall survival benefit of NA was 2.7 months (P=0.048). Those 19% of patients experiencing a significant histologic response to NA demonstrated further improved survival. CONCLUSIONS: NA improves survival in patients undergoing resection for locally advanced esophageal or EGJ cancer; however, the median benefit is <3 months in patients discharged postoperatively. Patients precluded from NA achieve acceptable oncological results but experience a higher risk of perioperative mortality.

Quantitative Shotgun Proteomics Unveils Candidate Novel Esophageal Adenocarcinoma (EAC)-specific Proteins.

Esophageal cancer is the eighth most common cancer worldwide and the majority of patients have systemic disease at presentation. Esophageal adenocarcinoma (OAC), the predominant subtype in western countries, is largely resistant to current chemotherapy regimens. Selective markers are needed to enhance clinical staging and to allow targeted therapies yet there are minimal proteomic data on this cancer type. After histological review, lysates from OAC and matched normal esophageal and gastric samples from seven patients were subjected to LC MS/MS after tandem mass tag labeling and OFFGEL fractionation. Patient matched samples of OAC, normal esophagus, normal stomach, lymph node metastases and uninvolved lymph nodes were used from an additional 115 patients for verification of expression by immunohistochemistry (IHC).Over six thousand proteins were identified and quantified across samples. Quantitative reproducibility was excellent between technical replicates and a moderate correlation was seen across samples with the same histology. The quantitative accuracy was verified across the dynamic range for seven proteins by immunohistochemistry (IHC) on the originating tissues. Multiple novel tumor-specific candidates are proposed and EPCAM was verified by IHC.This shotgun proteomic study of OAC used a comparative quantitative approach to reveal proteins highly expressed in specific tissue types. Novel tumor-specific proteins are proposed and EPCAM was demonstrated to be specifically overexpressed in primary tumors and lymph node metastases compared with surrounding normal tissues. This candidate and others proposed in this study could be developed as tumor-specific targets for novel clinical staging and therapeutic approaches.

M2 pyruvate kinase provides a mechanism for nutrient sensing and regulation of cell proliferation.

We show that the M2 isoform of pyruvate kinase (M2PYK) exists in equilibrium between monomers and tetramers regulated by allosteric binding of naturally occurring small-molecule metabolites. Phenylalanine stabilizes an inactive T-state tetrameric conformer and inhibits M2PYK with an IC50 value of 0.24 mM, whereas thyroid hormone (triiodo-L-thyronine, T3) stabilizes an inactive monomeric form of M2PYK with an IC50 of 78 nM. The allosteric activator fructose-1,6-bisphosphate [F16BP, AC50 (concentration that gives 50% activation) of 7 µM] shifts the equilibrium to the tetrameric active R-state, which has a similar activity to that of the constitutively fully active isoform M1PYK. Proliferation assays using HCT-116 cells showed that addition of inhibitors phenylalanine and T3 both increased cell proliferation, whereas addition of the activator F16BP reduced proliferation. F16BP abrogates the inhibitory effect of both phenylalanine and T3, highlighting a dominant role of M2PYK allosteric activation in the regulation of cancer proliferation. X-ray structures show constitutively fully active M1PYK and F16BP-bound M2PYK in an R-state conformation with a lysine at the dimer-interface acting as a peg in a hole, locking the active tetramer conformation. Binding of phenylalanine in an allosteric pocket induces a 13° rotation of the protomers, destroying the peg-in-hole R-state interface. This distinct T-state tetramer is stabilized by flipped out Trp/Arg side chains that stack across the dimer interface. X-ray structures and biophysical binding data of M2PYK complexes explain how, at a molecular level, fluctuations in concentrations of amino acids, thyroid hormone, and glucose metabolites switch M2PYK on and off to provide the cell with a nutrient sensing and growth signaling mechanism.

Follow the carrot: a route through the difficult esophagus or duodenum.

The side-viewing optics of the duodenoscope present a challenge during esophageal and duodenal intubation. Strictures and diverticula can make this challenge even greater. Techniques including intubation over a wire or through an overtube have been reported to allow passage of the duodenoscope in such cases. We have encountered 5 cases in which intubation was not possible despite using these techniques. The cases displayed a variety of endoscopic challenges and we devised a novel solution that allowed endoscopic retrograde cholangiopancreatography to be successfully completed in all. With this method all procedures could be effectively performed with no complications and no greater risk to the patient than conventional endoscopic retrograde cholangiopancreatography. This simple, low-cost technique could be adopted by any biliary endoscopist when standard techniques fail.