Pan-cancer proteogenomics characterization of tumor immunity.

Despite the successes of immunotherapy in cancer treatment over recent decades, less than <10%-20% cancer cases have demonstrated durable responses from immune checkpoint blockade. To enhance the efficacy of immunotherapies, combination therapies suppressing multiple immune evasion mechanisms are increasingly contemplated. To better understand immune cell surveillance and diverse immune evasion responses in tumor tissues, we comprehensively characterized the immune landscape of more than 1,000 tumors across ten different cancers using CPTAC pan-cancer proteogenomic data. We identified seven distinct immune subtypes based on integrative learning of cell type compositions and pathway activities. We then thoroughly categorized unique genomic, epigenetic, transcriptomic, and proteomic changes associated with each subtype. Further leveraging the deep phosphoproteomic data, we studied kinase activities in different immune subtypes, which revealed potential subtype-specific therapeutic targets. Insights from this work will facilitate the development of future immunotherapy strategies and enhance precision targeting with existing agents.

Pan-cancer analysis of post-translational modifications reveals shared patterns of protein regulation.

Post-translational modifications (PTMs) play key roles in regulating cell signaling and physiology in both normal and cancer cells. Advances in mass spectrometry enable high-throughput, accurate, and sensitive measurement of PTM levels to better understand their role, prevalence, and crosstalk. Here, we analyze the largest collection of proteogenomics data from 1,110 patients with PTM profiles across 11 cancer types (10 from the National Cancer Institute's Clinical Proteomic Tumor Analysis Consortium [CPTAC]). Our study reveals pan-cancer patterns of changes in protein acetylation and phosphorylation involved in hallmark cancer processes. These patterns revealed subsets of tumors, from different cancer types, including those with dysregulated DNA repair driven by phosphorylation, altered metabolic regulation associated with immune response driven by acetylation, affected kinase specificity by crosstalk between acetylation and phosphorylation, and modified histone regulation. Overall, this resource highlights the rich biology governed by PTMs and exposes potential new therapeutic avenues.

Pan-cancer proteogenomics connects oncogenic drivers to functional states.

Cancer driver events refer to key genetic aberrations that drive oncogenesis; however, their exact molecular mechanisms remain insufficiently understood. Here, our multi-omics pan-cancer analysis uncovers insights into the impacts of cancer drivers by identifying their significant cis-effects and distal trans-effects quantified at the RNA, protein, and phosphoprotein levels. Salient observations include the association of point mutations and copy-number alterations with the rewiring of protein interaction networks, and notably, most cancer genes converge toward similar molecular states denoted by sequence-based kinase activity profiles. A correlation between predicted neoantigen burden and measured T cell infiltration suggests potential vulnerabilities for immunotherapies. Patterns of cancer hallmarks vary by polygenic protein abundance ranging from uniform to heterogeneous. Overall, our work demonstrates the value of comprehensive proteogenomics in understanding the functional states of oncogenic drivers and their links to cancer development, surpassing the limitations of studying individual cancer types.

Proteogenomic Characterization Reveals Therapeutic Vulnerabilities in Lung Adenocarcinoma.

To explore the biology of lung adenocarcinoma (LUAD) and identify new therapeutic opportunities, we performed comprehensive proteogenomic characterization of 110 tumors and 101 matched normal adjacent tissues (NATs) incorporating genomics, epigenomics, deep-scale proteomics, phosphoproteomics, and acetylproteomics. Multi-omics clustering revealed four subgroups defined by key driver mutations, country, and gender. Proteomic and phosphoproteomic data illuminated biology downstream of copy number aberrations, somatic mutations, and fusions and identified therapeutic vulnerabilities associated with driver events involving KRAS, EGFR, and ALK. Immune subtyping revealed a complex landscape, reinforced the association of STK11 with immune-cold behavior, and underscored a potential immunosuppressive role of neutrophil degranulation. Smoking-associated LUADs showed correlation with other environmental exposure signatures and a field effect in NATs. Matched NATs allowed identification of differentially expressed proteins with potential diagnostic and therapeutic utility. This proteogenomics dataset represents a unique public resource for researchers and clinicians seeking to better understand and treat lung adenocarcinomas.

Proteogenomic Landscape of Breast Cancer Tumorigenesis and Targeted Therapy.

The integration of mass spectrometry-based proteomics with next-generation DNA and RNA sequencing profiles tumors more comprehensively. Here this "proteogenomics" approach was applied to 122 treatment-naive primary breast cancers accrued to preserve post-translational modifications, including protein phosphorylation and acetylation. Proteogenomics challenged standard breast cancer diagnoses, provided detailed analysis of the ERBB2 amplicon, defined tumor subsets that could benefit from immune checkpoint therapy, and allowed more accurate assessment of Rb status for prediction of CDK4/6 inhibitor responsiveness. Phosphoproteomics profiles uncovered novel associations between tumor suppressor loss and targetable kinases. Acetylproteome analysis highlighted acetylation on key nuclear proteins involved in the DNA damage response and revealed cross-talk between cytoplasmic and mitochondrial acetylation and metabolism. Our results underscore the potential of proteogenomics for clinical investigation of breast cancer through more accurate annotation of targetable pathways and biological features of this remarkably heterogeneous malignancy.

Perioperative Antiplatelet Bridging With Cangrelor: A Cohort Study and Narrative Review.

BACKGROUND: In patients who received a cardiac stent, practice guidelines recommend dual antiplatelet therapy (DAPT). However, an urgent procedure may be required necessitating interruption of DAPT. Intravenous cangrelor was previously shown to be an alternative due its short-half life and quick onset/offset. OBJECTIVE: To determine the safety and effectiveness of cangrelor bridging for patients undergoing invasive procedures in a veteran population. METHODS: Retrospective cohort of patients from Michael E. DeBakey VA Medical Center and the VA North Texas Health Care Systems who underwent perioperative cangrelor bridging. The primary outcome was the incidence of bleeding using the Bleeding Academic Research Consortium (BARC) criteria. The secondary outcome was a composite of nonfatal stroke, myocardial infarction (MI), mortality, and unplanned revascularization within 30 days. A narrative review was also performed to summarize cangrelor bridging for noncardiac invasive procedure. RESULTS: There were 41 patients that met the eligibility criteria. Patients were predominantly Caucasian (57.5%) men with a median age of 70 years. The median duration on cangrelor bridging was 2.6 days with 11 and 30 patients undergoing cardiac and noncardiac invasive procedures, respectively. Nine patients (22%) had a bleeding event of which 8 were minor. One was severe due to significant iliopsoas hematoma following drain placement. All bleeding events occurred postoperatively except for 2 perioperative events that occurred during orthopedic procedures. Ischemic events up to 30 days occurred in 3 patients (7.3%) which consisted of 1 (2.4%) nonfatal MI requiring revascularization and 2 (4.9%) deaths, 1 of which was sudden cardiac. CONCLUSION AND RELEVANCE: This study suggests that cangrelor bridging may be a reasonable alternative to holding oral P2Y12 inhibitors in patients requiring interruption of antiplatelet therapy for an urgent surgery/invasive procedure.

A highly multiplexed quantitative phosphosite assay for biology and preclinical studies.

Reliable methods to quantify dynamic signaling changes across diverse pathways are needed to better understand the effects of disease and drug treatment in cells and tissues but are presently lacking. Here, we present SigPath, a targeted mass spectrometry (MS) assay that measures 284 phosphosites in 200 phosphoproteins of biological interest. SigPath probes a broad swath of signaling biology with high throughput and quantitative precision. We applied the assay to investigate changes in phospho-signaling in drug-treated cancer cell lines, breast cancer preclinical models, and human medulloblastoma tumors. In addition to validating previous findings, SigPath detected and quantified a large number of differentially regulated phosphosites newly associated with disease models and human tumors at baseline or with drug perturbation. Our results highlight the potential of SigPath to monitor phosphoproteomic signaling events and to nominate mechanistic hypotheses regarding oncogenesis, response, and resistance to therapy.

Proteogenomics connects somatic mutations to signalling in breast cancer.

Somatic mutations have been extensively characterized in breast cancer, but the effects of these genetic alterations on the proteomic landscape remain poorly understood. Here we describe quantitative mass-spectrometry-based proteomic and phosphoproteomic analyses of 105 genomically annotated breast cancers, of which 77 provided high-quality data. Integrated analyses provided insights into the somatic cancer genome including the consequences of chromosomal loss, such as the 5q deletion characteristic of basal-like breast cancer. Interrogation of the 5q trans-effects against the Library of Integrated Network-based Cellular Signatures, connected loss of CETN3 and SKP1 to elevated expression of epidermal growth factor receptor (EGFR), and SKP1 loss also to increased SRC tyrosine kinase. Global proteomic data confirmed a stromal-enriched group of proteins in addition to basal and luminal clusters, and pathway analysis of the phosphoproteome identified a G-protein-coupled receptor cluster that was not readily identified at the mRNA level. In addition to ERBB2, other amplicon-associated highly phosphorylated kinases were identified, including CDK12, PAK1, PTK2, RIPK2 and TLK2. We demonstrate that proteogenomic analysis of breast cancer elucidates the functional consequences of somatic mutations, narrows candidate nominations for driver genes within large deletions and amplified regions, and identifies therapeutic targets.

Biomarkers to Distinguish Bacterial From Viral Pediatric Clinical Pneumonia in a Malaria-Endemic Setting.

BACKGROUND: Differential etiologies of pediatric acute febrile respiratory illness pose challenges for all populations globally, but especially in malaria-endemic settings because the pathogens responsible overlap in clinical presentation and frequently occur together. Rapid identification of bacterial pneumonia with high-quality diagnostic tools would enable appropriate, point-of-care antibiotic treatment. Current diagnostics are insufficient, and the discovery and development of new tools is needed. We report a unique biomarker signature identified in blood samples to accomplish this. METHODS: Blood samples from 195 pediatric Mozambican patients with clinical pneumonia were analyzed with an aptamer-based, high-dynamic-range, quantitative assay (~1200 proteins). We identified new biomarkers using a training set of samples from patients with established bacterial, viral, or malarial pneumonia. Proteins with significantly variable abundance across etiologies (false discovery rate <0.01) formed the basis for predictive diagnostic models derived from machine learning techniques (Random Forest, Elastic Net). Validation on a dedicated test set of samples was performed. RESULTS: Significantly different abundances between bacterial and viral infections (219 proteins) and bacterial infections and mixed (viral and malaria) infections (151 proteins) were found. Predictive models achieved >90% sensitivity and >80% specificity, regardless of number of pathogen classes. Bacterial pneumonia was strongly associated with neutrophil markers-in particular, degranulation including HP, LCN2, LTF, MPO, MMP8, PGLYRP1, RETN, SERPINA1, S100A9, and SLPI. CONCLUSIONS: Blood protein signatures highly associated with neutrophil biology reliably differentiated bacterial pneumonia from other causes. With appropriate technology, these markers could provide the basis for a rapid diagnostic for field-based triage for antibiotic treatment of pediatric pneumonia.

Ins and Outs: Perspectives of Inpatient Prescribing for Sacubitril/Valsartan.

Heart failure is a major public health concern with a rising prevalence and significant financial detriment. Although sacubitril/valsartan was shown to reduce the risk of death and hospitalization from heart failure in a contemporary cohort, it continues to remain substantially underutilized. A recent article in the Annals highlights the evidence behind inpatient initiation of sacubitril/valsartan. We provide further considerations and summarize the evidence for inpatient initiation of other guideline directed medical therapies. Overall, there is a need to improve methods to identify ideal populations and increase utilization in those who may benefit from sacubitril/valsartan. Further research is also needed to identify the risks versus benefits among underrepresented populations (i.e., advanced heart failure, heart failure with preserved ejection fraction, in conjunction with other contemporary evidence-based therapies that can lower blood pressure, etc.).

A Curated Resource for Phosphosite-specific Signature Analysis.

Signaling pathways are orchestrated by post-translational modifications (PTMs) such as phosphorylation. However, pathway analysis of PTM data sets generated by mass spectrometry (MS)-based proteomics is typically performed at a gene-centric level because of the lack of appropriately curated PTM signature databases and bioinformatic tools that leverage PTM site-specific information. Here we present the first version of PTMsigDB, a database of modification site-specific signatures of perturbations, kinase activities and signaling pathways curated from more than 2,500 publications. We adapted the widely used single sample Gene Set Enrichment Analysis approach to utilize PTMsigDB, enabling PTMSignature Enrichment Analysis (PTM-SEA) of quantitative MS data. We used a well-characterized data set of epidermal growth factor (EGF)-perturbed cancer cells to evaluate our approach and demonstrated better representation of signaling events compared with gene-centric methods. We then applied PTM-SEA to analyze the phosphoproteomes of cancer cells treated with cell-cycle inhibitors and detected mechanism-of-action specific signatures of cell cycle kinases. We also applied our methods to analyze the phosphoproteomes of PI3K-inhibited human breast cancer cells and detected signatures of compounds inhibiting PI3K as well as targets downstream of PI3K (AKT, MAPK/ERK) covering a substantial fraction of the PI3K pathway. PTMsigDB and PTM-SEA can be freely accessed at https://github.com/broadinstitute/ssGSEA2.0.

Reflections of the Angiotensin Receptor Blocker Recall by the FDA and Repercussions on Healthcare.

PURPOSE: Beginning in July of 2018, the FDA issued a voluntary recall regarding the presence of a contaminant found in the manufacturing of valsartan. What would ensue has become a largely unprecedented sequence of alarming events since the FDA began reporting public recalls, withdrawals and safety alerts on their website in 2016. Since then, the United States has been significantly impacted by drug recalls affecting angiotensin receptor blockers. This report arms clinicians with additional guidance and provides a framework for responding appropriately to future similar incidents and includes an overview of the angiotensin receptor blockers, and their effects and safety profiles. METHODS: This report includes a review of data from all pertinent clinical and scientific sources including information from the FDA's inspection documents and recall website. Additional information is provided on the specific bottles including all lot numbers, expiration dates, etc. RESULTS: The recalls/withdrawals are attributable to the presence of cancer-causing contaminants identified during the manufacturing process from drug manufacturers abroad. The root causes behind the recalls and subsequent shortage appear multifactorial, and stem to a certain extent from the outsourcing of medication manufacturing overseas and lack of quality checks and appropriate oversight. CONCLUSIONS: This inherent issue is not likely to resolve soon and has eroded the public trust of/in the healthcare system and the pharmaceutical industry. Patients and healthcare providers are significantly affected and should have a full understanding of the matter in order to guide appropriate response and actions.

Transcriptional Categorization of the Etiology of Pneumonia Syndrome in Pediatric Patients in Malaria-Endemic Areas.

Background: Pediatric acute respiratory distress in tropical settings is very common. Bacterial pneumonia is a major contributor to morbidity and mortality rates and requires adequate diagnosis for correct treatment. A rapid test that could identify bacterial (vs other) infections would have great clinical utility. Methods and Results: We performed RNA (RNA-seq) sequencing and analyzed the transcriptomes of 68 pediatric patients with well-characterized clinical phenotype to identify transcriptional features associated with each disease class. We refined the features to predictive models (support vector machine, elastic net) and validated those models in an independent test set of 37 patients (80%-85% accuracy). Conclusions: We have identified sets of genes that are differentially expressed in pediatric patients with pneumonia syndrome attributable to different infections and requiring different therapeutic interventions. Findings of this study demonstrate that human transcription signatures in infected patients recapitulate the underlying biology and provide models for predicting a bacterial diagnosis to inform treatment.

Multiplexed, Quantitative Workflow for Sensitive Biomarker Discovery in Plasma Yields Novel Candidates for Early Myocardial Injury.

We have developed a novel plasma protein analysis platform with optimized sample preparation, chromatography, and MS analysis protocols. The workflow, which utilizes chemical isobaric mass tag labeling for relative quantification of plasma proteins, achieves far greater depth of proteome detection and quantification while simultaneously having increased sample throughput than prior methods. We applied the new workflow to a time series of plasma samples from patients undergoing a therapeutic, "planned" myocardial infarction for hypertrophic cardiomyopathy, a unique human model in which each person serves as their own biologic control. Over 5300 proteins were confidently identified in our experiments with an average of 4600 proteins identified per sample (with two or more distinct peptides identified per protein) using iTRAQ four-plex labeling. Nearly 3400 proteins were quantified in common across all 16 patient samples. Compared with a previously published label-free approach, the new method quantified almost fivefold more proteins/sample and provided a six- to nine-fold increase in sample analysis throughput. Moreover, this study provides the largest high-confidence plasma proteome dataset available to date. The reliability of relative quantification was also greatly improved relative to the label-free approach, with measured iTRAQ ratios and temporal trends correlating well with results from a 23-plex immunoMRM (iMRM) assay containing a subset of the candidate proteins applied to the same patient samples. The functional importance of improved detection and quantification was reflected in a markedly expanded list of significantly regulated proteins that provided many new candidate biomarker proteins. Preliminary evaluation of plasma sample labeling with TMT six-plex and ten-plex reagents suggests that even further increases in multiplexing of plasma analysis are practically achievable without significant losses in depth of detection relative to iTRAQ four-plex. These results obtained with our novel platform provide clear demonstration of the value of using isobaric mass tag reagents in plasma-based biomarker discovery experiments.

Responses to Bacteria, Virus, and Malaria Distinguish the Etiology of Pediatric Clinical Pneumonia.

RATIONALE: Plasma-detectable biomarkers that rapidly and accurately diagnose bacterial infections in children with suspected pneumonia could reduce the morbidity of respiratory disease and decrease the unnecessary use of antibiotic therapy. OBJECTIVES: Using 56 markers measured in a multiplexed immunoassay, we sought to identify proteins and protein combinations that could discriminate bacterial from viral or malarial diagnoses. METHODS: We selected 80 patients with clinically diagnosed pneumonia (as defined by the World Health Organization) who also met criteria for bacterial, viral, or malarial infection based on clinical, radiographic, and laboratory results. Ten healthy community control subjects were enrolled to assess marker reliability. Patients were subdivided into two sets: one for identifying potential markers and another for validating them. MEASUREMENTS AND MAIN RESULTS: Three proteins (haptoglobin, tumor necrosis factor receptor 2 or IL-10, and tissue inhibitor of metalloproteinases 1) were identified that, when combined through a classification tree signature, accurately classified patients into bacterial, malarial, and viral etiologies and misclassified only one patient with bacterial pneumonia from the validation set. The overall sensitivity and specificity of this signature for the bacterial diagnosis were 96 and 86%, respectively. Alternative combinations of markers with comparable accuracy were selected by support vector machine and regression models and included haptoglobin, IL-10, and creatine kinase-MB. CONCLUSIONS: Combinations of plasma proteins accurately identified children with a respiratory syndrome who were likely to have bacterial infections and who would benefit from antibiotic therapy. When used in conjunction with malaria diagnostic tests, they may improve diagnostic specificity and simplify treatment decisions for clinicians.

Quantitative analysis of peptides and proteins in biomedicine by targeted mass spectrometry.

Targeted mass spectrometry (MS) is becoming widely used in academia and in pharmaceutical and biotechnology industries for sensitive and quantitative detection of proteins, peptides and post-translational modifications. Here we describe the increasing importance of targeted MS technologies in clinical proteomics and the potential key roles these techniques will have in bridging biomedical discovery and clinical implementation.

Integrated proteomic analysis of post-translational modifications by serial enrichment.

We report a mass spectrometry-based method for the integrated analysis of protein expression, phosphorylation, ubiquitination and acetylation by serial enrichments of different post-translational modifications (SEPTM) from the same biological sample. This technology enabled quantitative analysis of nearly 8,000 proteins and more than 20,000 phosphorylation, 15,000 ubiquitination and 3,000 acetylation sites per experiment, generating a holistic view of cellular signal transduction pathways as exemplified by analysis of bortezomib-treated human leukemia cells.

Antiplatelet Management for Coronary Heart Disease: Advances and Challenges.

Coronary heart disease (CHD) remains the leading cause of death in the USA. CHD accounts for 48 % of all cardiovascular mortality or approximately one of every seven deaths. Disruption of atherosclerotic plaques--usually by rupture or erosion--and superimposed thrombosis can result in acute coronary syndromes and sudden cardiac death. Silent plaque disruption may also occur and result in coronary plaque progression and ultimately the symptomatic manifestations of stable CHD. Antiplatelet agents remain the cornerstone therapy for acute thrombotic coronary syndromes and are essential for thromboprophylaxis against these events in patients with stable CHD. Antiplatelet drugs are also important adjunct therapies during percutaneous coronary intervention (PCI) as they mitigate equipment-associated thrombotic complications that are partially induced by iatrogenic plaque rupture by interventionalists during balloon angioplasty in the cardiac catheterization laboratory. Since the introduction of clopidogrel, there has been considerable development in this field with at least three novel P2Y12 antagonists approved by the Food and Drug Administration (FDA) over the past decade. Rapidly accumulating evidence is helping to guide the optimal duration of treatment with dual antiplatelet therapy after stenting, especially with the newer drug-eluting stents. More data are also emerging on the hazards and long-term safety of these agents. It is therefore prudent for clinicians to remain current on treatment options and recent advances in this area. We herein review current and emerging antiplatelet therapies and summarize their characteristics and indications of use as well as challenges and areas of ongoing research.

Simplified and efficient quantification of low-abundance proteins at very high multiplex via targeted mass spectrometry.

Liquid chromatography-multiple reaction monitoring mass spectrometry (LC-MRM-MS) of plasma that has been depleted of abundant proteins and fractionated at the peptide level into six to eight fractions is a proven method for quantifying proteins present at low nanogram-per-milliliter levels. A drawback of fraction-MRM is the increased analysis time due to the generation of multiple fractions per biological sample. We now report that the use of heated, long, fused silica columns (>30 cm) packed with 1.9 µm of packing material can reduce or eliminate the need for fractionation prior to LC-MRM-MS without a significant loss of sensitivity or precision relative to fraction-MRM. We empirically determined the optimal column length, temperature, gradient duration, and sample load for such assays and used these conditions to study detection sensitivity and assay precision. In addition to increased peak capacity, longer columns packed with smaller beads tolerated a 4- to 6-fold increase in analyte load without a loss of robustness or reproducibility. The longer columns also provided a 4-fold improvement in median limit-of-quantitation values with increased assay precision relative to the standard 12 cm columns packed with 3 µm material. Overall, the optimized chromatography provided an approximately 3-fold increase in analysis throughput with excellent robustness and less than a 2-fold reduction in quantitative sensitivity relative to fraction-MRM. The value of the system for increased multiplexing was demonstrated by the ability to configure an 800-plex MRM-MS assay, run in a single analysis, comprising 2400 transitions with retention time scheduling to monitor 400 unlabeled and heavy labeled peptide pairs.