An Aspirin a Day: New Pharmacological Developments and Cancer Chemoprevention.

Chemoprevention refers to the use of natural or synthetic agents to reverse, suppress, or prevent the progression or recurrence of cancer. A large body of preclinical and clinical data suggest the ability of aspirin to prevent precursor lesions and cancers, but much of the clinical data are inferential and based on descriptive epidemiology, case control, and cohort studies or studies designed to answer other questions (e.g., cardiovascular mortality). Multiple pharmacological, clinical, and epidemiologic studies suggest that aspirin can prevent certain cancers but may also cause other effects depending on the tissue or disease and organ site in question. The best-known biological targets of aspirin are cyclooxygenases, which drive a wide variety of functions, including hemostasis, inflammation, and immune modulation. Newly recognized molecular and cellular interactions suggest additional modifiable functional targets, and the existence of consensus molecular cancer subtypes suggests that aspirin may have differential effects based on tumor heterogeneity. This review focuses on new pharmacological developments and innovations in biopharmacology that clarify the potential role of aspirin in cancer chemoprevention.

Of vascular defense, hemostasis, cancer, and platelet biology: an evolutionary perspective.

We have established considerable expertise in studying the role of platelets in cancer biology. From this expertise, we were keen to recognize the numerous venous-, arterial-, microvascular-, and macrovascular thrombotic events and immunologic disorders are caused by severe, acute-respiratory-syndrome coronavirus 2 (SARS-CoV-2) infections. With this offering, we explore the evolutionary connections that place platelets at the center of hemostasis, immunity, and adaptive phylogeny. Coevolutionary changes have also occurred in vertebrate viruses and their vertebrate hosts that reflect their respective evolutionary interactions. As mammals adapted from aquatic to terrestrial life and the heavy blood loss associated with placentalization-based live birth, platelets evolved phylogenetically from thrombocytes toward higher megakaryocyte-blebbing-based production rates and the lack of nuclei. With no nuclei and robust RNA synthesis, this adaptation may have influenced viral replication to become less efficient after virus particles are engulfed. Human platelets express numerous receptors that bind viral particles, which developed from archetypal origins to initiate aggregation and exocytic-release of thrombo-, immuno-, angiogenic-, growth-, and repair-stimulatory granule contents. Whether by direct, evolutionary, selective pressure, or not, these responses may help to contain virus spread, attract immune cells for eradication, and stimulate angiogenesis, growth, and wound repair after viral damage. Because mammalian and marsupial platelets became smaller and more plate-like their biophysical properties improved in function, which facilitated distribution near vessel walls in fluid-shear fields. This adaptation increased the probability that platelets could then interact with and engulf shedding virus particles. Platelets also generate circulating microvesicles that increase membrane surface-area encounters and mark viral targets. In order to match virus-production rates, billions of platelets are generated and turned over per day to continually provide active defenses and adaptation to suppress the spectrum of evolving threats like SARS-CoV-2.

Phase 1 study of the safety, pharmacokinetics, and preliminary efficacy of CA102N as monotherapy and in combination with trifluridine-tipiracil in patients with locally advanced or metastatic solid tumors.

CA102N is a covalently bound conjugate of modified nimesulide (Nim) and NaHA, the sodium salt of hyaluronic acid (HA). HA is a natural ligand of cluster of differentiation 44 (CD44), which is over-expressed in colorectal cancer (CRC). CA102N is designed to deliver nimesulide directly to the tumor via the interaction of HA and CD44. A Phase 1, 2-part (dose escalation, dose expansion), non-randomized, open-label, first-in-human study of CA102N, as monotherapy and in combination with trifluridine-tipiracil, was conducted in patients with locally advanced or metastatic solid tumors. The CA102N doses evaluated were 0.36 mg/kg, 0.54 mg/kg, and 0.72 mg/kg Nim equivalent. The primary endpoints were dose-limiting toxicities (DLTs) in Cycle 1 as well as serious adverse events (SAEs) and treatment-emergent adverse events (TEAEs) throughout the study; secondary endpoints were pharmacodynamics parameters, objective tumor response, and urinary pharmacodynamics markers of target inhibition. Between April 2019 and October 2021, 37 patients were enrolled in 3 US centers. No DLTs were observed in Part 1, and 0.72 mg/kg Nim equivalent was the dose selected for Part 2. In total, 52 TEAEs in 18 patients were CA102N-related; 4 (in 3 patients) were ≥ Grade 3. Exploratory analysis in the dose expansion cohort revealed a median progression-free survival of 3.7 (1.0, 6.77) months. Based on this study, CA102N as monotherapy or in combination with trifluridine-tipiracil, was safe and well-tolerated at the recommended Phase 2 dose of 0.72 mg/kg Nim equivalent in patients with locally advanced or metastatic solid tumors. Preliminary evidence of antitumor activity in CRC warrants further clinical development. (ClinicalTrials.gov registration number: NCT03616574. Registration date: August 6, 2018).

Sequential Administration of XPO1 and ATR Inhibitors Enhances Therapeutic Response in TP53-mutated Colorectal Cancer.

BACKGROUND & AIMS: Understanding the mechanisms by which tumors adapt to therapy is critical for developing effective combination therapeutic approaches to improve clinical outcomes for patients with cancer. METHODS: To identify promising and clinically actionable targets for managing colorectal cancer (CRC), we conducted a patient-centered functional genomics platform that includes approximately 200 genes and paired this with a high-throughput drug screen that includes 262 compounds in four patient-derived xenografts (PDXs) from patients with CRC. RESULTS: Both screening methods identified exportin 1 (XPO1) inhibitors as drivers of DNA damage-induced lethality in CRC. Molecular characterization of the cellular response to XPO1 inhibition uncovered an adaptive mechanism that limited the duration of response in TP53-mutated, but not in TP53-wild-type CRC models. Comprehensive proteomic and transcriptomic characterization revealed that the ATM/ATR-CHK1/2 axes were selectively engaged in TP53-mutant CRC cells upon XPO1 inhibitor treatment and that this response was required for adapting to therapy and escaping cell death. Administration of KPT-8602, an XPO1 inhibitor, followed by AZD-6738, an ATR inhibitor, resulted in dramatic antitumor effects and prolonged survival in TP53-mutant models of CRC. CONCLUSIONS: Our findings anticipate tremendous therapeutic benefit and support the further evaluation of XPO1 inhibitors, especially in combination with DNA damage checkpoint inhibitors, to elicit an enduring clinical response in patients with CRC harboring TP53 mutations.

Methylation-eQTL analysis in cancer research.

MOTIVATION: DNA methylation is a key epigenetic factor regulating gene expression. While promoter methylation has been well studied, recent publications have revealed that functionally important methylation also occurs in intergenic and distal regions, and varies across genes and tissue types. Given the growing importance of inter-platform integrative genomic analyses, there is an urgent need to develop methods to discover and characterize gene-level relationships between methylation and expression. RESULTS: We introduce a novel sequential penalized regression approach to identify methylation-expression quantitative trait loci (methyl-eQTLs), a term that we have coined to represent, for each gene and tissue type, a sparse set of CpG loci best explaining gene expression and accompanying weights indicating direction and strength of association. Using TCGA and MD Anderson colorectal cohorts to build and validate our models, we demonstrate our strategy better explains expression variability than current commonly used gene-level methylation summaries. The methyl-eQTLs identified by our approach can be used to construct gene-level methylation summaries that are maximally correlated with gene expression for use in integrative models, and produce a tissue-specific summary of which genes appear to be strongly regulated by methylation. Our results introduce an important resource to the biomedical community for integrative genomics analyses involving DNA methylation. AVAILABILITY AND IMPLEMENTATION: We produce an R Shiny app (https://rstudio-prd-c1.pmacs.upenn.edu/methyl-eQTL/) that interactively presents methyl-eQTL results for colorectal, breast and pancreatic cancer. The source R code for this work is provided in the Supplementary Material. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

The Long Noncoding RNA CCAT2 Induces Chromosomal Instability Through BOP1-AURKB Signaling.

BACKGROUND & AIMS: Chromosomal instability (CIN) is a carcinogenesis event that promotes metastasis and resistance to therapy by unclear mechanisms. Expression of the colon cancer-associated transcript 2 gene (CCAT2), which encodes a long noncoding RNA (lncRNA), associates with CIN, but little is known about how CCAT2 lncRNA regulates this cancer enabling characteristic. METHODS: We performed cytogenetic analysis of colorectal cancer (CRC) cell lines (HCT116, KM12C/SM, and HT29) overexpressing CCAT2 and colon organoids from C57BL/6N mice with the CCAT2 transgene and without (controls). CRC cells were also analyzed by immunofluorescence microscopy, γ-H2AX, and senescence assays. CCAT2 transgene and control mice were given azoxymethane and dextran sulfate sodium to induce colon tumors. We performed gene expression array and mass spectrometry to detect downstream targets of CCAT2 lncRNA. We characterized interactions between CCAT2 with downstream proteins using MS2 pull-down, RNA immunoprecipitation, and selective 2'-hydroxyl acylation analyzed by primer extension analyses. Downstream proteins were overexpressed in CRC cells and analyzed for CIN. Gene expression levels were measured in CRC and non-tumor tissues from 5 cohorts, comprising more than 900 patients. RESULTS: High expression of CCAT2 induced CIN in CRC cell lines and increased resistance to 5-fluorouracil and oxaliplatin. Mice that expressed the CCAT2 transgene developed chromosome abnormalities, and colon organoids derived from crypt cells of these mice had a higher percentage of chromosome abnormalities compared with organoids from control mice. The transgenic mice given azoxymethane and dextran sulfate sodium developed more and larger colon polyps than control mice given these agents. Microarray analysis and mass spectrometry indicated that expression of CCAT2 increased expression of genes involved in ribosome biogenesis and protein synthesis. CCAT2 lncRNA interacted directly with and stabilized BOP1 ribosomal biogenesis factor (BOP1). CCAT2 also increased expression of MYC, which activated expression of BOP1. Overexpression of BOP1 in CRC cell lines resulted in chromosomal missegregation errors, and increased colony formation, and invasiveness, whereas BOP1 knockdown reduced viability. BOP1 promoted CIN by increasing the active form of aurora kinase B, which regulates chromosomal segregation. BOP1 was overexpressed in polyp tissues from CCAT2 transgenic mice compared with healthy tissue. CCAT2 lncRNA and BOP1 mRNA or protein were all increased in microsatellite stable tumors (characterized by CIN), but not in tumors with microsatellite instability compared with nontumor tissues. Increased levels of CCAT2 lncRNA and BOP1 mRNA correlated with each other and with shorter survival times of patients. CONCLUSIONS: We found that overexpression of CCAT2 in colon cells promotes CIN and carcinogenesis by stabilizing and inducing expression of BOP1 an activator of aurora kinase B. Strategies to target this pathway might be developed for treatment of patients with microsatellite stable colorectal tumors.

Sulindac plus a phospholipid is effective for polyp reduction and safer than sulindac alone in a mouse model of colorectal cancer development.

BACKGROUND: Non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin and sulindac are effective for colorectal cancer prevention in humans and some animal models, but concerns over gastro-intestinal (GI) ulceration and bleeding limit their potential for chemopreventive use in broader populations. Recently, the combination of aspirin with a phospholipid, packaged as PL-ASA, was shown to reduce GI toxicity in a small clinical trial. However, these studies were done for relatively short periods of time. Since prolonged, regular use is needed for chemopreventive benefit, it is important to know whether GI safety is maintained over longer use periods and whether cancer prevention efficacy is preserved when an NSAID is combined with a phospholipid. METHODS: As a first step to answering these questions, we treated seven to eight-week-old, male and female C57B/6 Apcmin/+ mice with the NSAID sulindac, with and without phosphatidylcholine (PC) for 3-weeks. At the end of the treatment period, we evaluated polyp burden, gastric toxicity, urinary prostaglandins (as a marker of sulindac target engagement), and blood chemistries. RESULTS: Both sulindac and sulindac-PC treatments resulted in significantly reduced polyp burden, and decreased urinary prostaglandins, but sulindac-PC treatment also resulted in the reduction of gastric lesions compared to sulindac alone. CONCLUSIONS: Together these data provide pre-clinical support for combining NSAIDs with a phospholipid, such as phosphatidylcholine to reduce GI toxicity while maintaining chemopreventive efficacy.

Bioactive lipid metabolism in platelet "first responder" and cancer biology.

Platelets can serve as "first responders" in cancer and metastasis. This is partly due to bioactive lipid metabolism that drives both platelet and cancer biology. The two primary eicosanoid metabolites that maintain platelet rapid response homeostasis are prostacyclin made by endothelial cells that inhibits platelet function, which is counterbalanced by thromboxane produced by platelets during activation, aggregation, and platelet recruitment. Both of these arachidonic acid metabolites are inherently unstable due to their chemical structure. Tumor cells by contrast predominantly make more chemically stable prostaglandin E2, which is the primary bioactive lipid associated with inflammation and oncogenesis. Pharmacological, clinical, and epidemiologic studies demonstrate that non-steroidal anti-inflammatory drugs (NSAIDs), which target cyclooxygenases, can help prevent cancer. Much of the molecular and biological impact of these drugs is generally accepted in the field. Cyclooxygenases catalyze the rate-limiting production of substrate used by all synthase molecules, including those that produce prostaglandins along with prostacyclin and thromboxane. Additional eicosanoid metabolites include lipoxygenases, leukotrienes, and resolvins that can also influence platelets, inflammation, and carcinogenesis. Our knowledge base and technology are now progressing toward identifying newer molecular and cellular interactions that are leading to revealing additional targets. This review endeavors to summarize new developments in the field.

Clinical and molecular characterization of early-onset colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) incidence is increasing in adults younger than 50 years. This study evaluated clinical and molecular features to identify those features unique to early-onset CRC that differentiate these patients from patients 50 years old or older. METHODS: Baseline characteristics were evaluated according to the CRC onset age with 3 independent cohorts. A fourth cohort was used to describe the impact of age on the consensus molecular subtype (CMS) prevalence. RESULTS: This retrospective review of more than 36,000 patients with CRC showed that early-onset patients were more likely to have microsatellite instability (P = .038), synchronous metastatic disease (P = .009), primary tumors in the distal colon or rectum (P < .0001), and fewer BRAF V600 mutations (P < .001) in comparison with patients 50 years old or older. Patients aged 18 to 29 years had fewer adenomatous polyposis coli (APC) mutations (odds ratio [OR], 0.56; 95% confidence interval [CI], 0.35-0.90; P = .015) and an increased prevalence of signet ring histology (OR, 4.89; 95% CI, 3.23-7.39; P < .0001) in comparison with other patients younger than 50 years. In patients younger than 40 years, CMS1 was the most common subtype, whereas CMS3 and CMS4 were uncommon (P = .003). CMS2 was relatively stable across age groups. Early-onset patients with inflammatory bowel disease were more likely to have mucinous or signet ring histology (OR, 5.54; 95% CI, 2.24-13.74; P = .0004) and less likely to have APC mutations (OR, 0.24; 95% CI, 0.07-0.75; P = .019) in comparison with early-onset patients without predisposing conditions. CONCLUSIONS: Early-onset CRC is not only distinct from traditional CRC: special consideration should be given to and further investigations should be performed for both very young patients with CRC (18-29 years) and those with predisposing conditions. The etiology of the high rate of CMS1 in patients younger than 40 years deserves further exploration.

Signet ring cell colorectal cancer: genomic insights into a rare subpopulation of colorectal adenocarcinoma.

BACKGROUND: Signet ring cell carcinoma (SRCC) is a rare subtype of colorectal cancer (CRC). The aim of this study was to characterise the genomic alterations and outcomes of SRCC. METHODS: Medical records of metastatic CRC (mCRC) patients whose tumours were evaluated by NGS analysis were reviewed. SC-mCRC were classified into two groups: SRCC (>50% signet ring cells) and adenocarcinoma (AC) with SC component (≤50% signet ring cells). RESULTS: Six hundred and sixty-five mCRC patients were included. Of the 93 mCRC cases with SC features, 63 had slides for review. Of those 63 cases, 35 were confirmed SRCC, and 28 were AC with SC component. Compared with AC group, KRAS and PIK3CA mutations (mts) were found in only 11% (OR: 0.13) and 3% (OR: 0.15) of SRCC cases, respectively. In contrast to the 44% rate of APC mts in AC group, only 3% of SRCC patients had APC mts (OR = 0.04). CONCLUSIONS: SRCC has distinct molecular features, including low rates of KRAS, PIK3CA and APC mts. Further study to identify activation pathways and potential therapeutic targets are needed.

Circulating inflammation signature predicts overall survival and relapse-free survival in metastatic colorectal cancer.

BACKGROUND: Metastatic colorectal cancer (mCRC) is a highly heterogeneous disease from a clinical, molecular, and immunological perspective. Current predictive models rely primarily in tissue based genetic analysis, which not always correlate with inflammatory response. Here we evaluated the role of a circulating inflammatory signature as a prognostic marker in mCRC. METHODS: Two hundred eleven newly diagnosed patients with mCRC were enrolled in the study. One hundred twenty-one patients had unresectable metastases, whereas ninety patients had potentially resectable liver metastases at presentation. Analysis of miR-21, IL-6, and IL-8 in the plasma of peripheral blood was performed at baseline. Patients with high circulating levels of ≥2 of the three inflammation markers (miR-21, IL-6, and IL-8) were considered to have the "Inflammation phenotype-positive CISIG". RESULTS: Positive CISIG was found in 39/90 (43%) and 50/121 (45%) patients in the resectable and unresectable cohort, respectively. In the resectable population the median relapse-free survival was 18.4 compared to 31.4 months (p = 0.001 HR 2.09, 95% CI 1.2-3.67) for positive vs. negative CISIG. In contrast, the individual components were not significant. In the same population the median overall survival was 46.2 compared to 66.0 months (p = 0.0003, HR 2.57, 95% CI 1.26-5.27) for positive vs. negative CISIG, but not significant for the individual components. In the unresectable population, the median overall survival was 13.5 compared to 25.0 months (p = 0.0008, HR 2.49, 95% CI 1.46-4.22) for positive vs. negative CISIG. IL-6 was independently prognostic with overall survival of 16.2 compared to 27.0 months (p = 0.004, HR 1.96, 95% CI 1.24-3.11) for high vs. low IL-6, but not the other components. Using a Cox regression model, we demonstrated that CISIG is an independent predictive marker of survival in patients with unresectable disease (HR 1.8, 95% CI 1.2, 2.8, p < 0.01). CONCLUSION: In two different cohorts, we demonstrated that CISIG is a strong prognostic factor of relapse-free and overall survival of patients with mCRC. Based on these data, analysis of circulating inflammatory signaling can be complimentary to traditional molecular testing.

Back to the Colorectal Cancer Consensus Molecular Subtype Future.

PURPOSE OF REVIEW: This review seeks to provide an informed prospective on the advances in molecular profiling and analysis of colorectal cancer (CRC). The goal is to provide a historical context and current summary on how advances in gene and protein sequencing technology along with computer capabilities led to our current bioinformatic advances in the field. RECENT FINDINGS: An explosion of knowledge has occurred regarding genetic, epigenetic, and biochemical alterations associated with the evolution of colorectal cancer. This has led to the realization that CRC is a heterogeneous disease with molecular alterations often dictating natural history, response to treatment, and outcome. The consensus molecular subtypes (CMS) classification classifies CRC into four molecular subtypes with distinct biological characteristics, which may form the basis for clinical stratification and subtype-based targeted intervention. This review summarizes new developments of a field moving "Back to the Future." CRC molecular subtyping will better identify key subtype specific therapeutic targets and responses to therapy.

Real-Time Interrogation of Aspirin Reactivity, Biochemistry, and Biodistribution by Hyperpolarized Magnetic Resonance Spectroscopy.

Hyperpolarized magnetic resonance spectroscopy enables quantitative, non-radioactive, real-time measurement of imaging probe biodistribution and metabolism in vivo. Here, we investigate and report on the development and characterization of hyperpolarized acetylsalicylic acid (aspirin) and its use as a nuclear magnetic resonance (NMR) probe. Aspirin derivatives were synthesized with single- and double-13 C labels and hyperpolarized by dynamic nuclear polarization with 4.7 % and 3 % polarization, respectively. The longitudinal relaxation constants (T1 ) for the labeled acetyl and carboxyl carbonyls were approximately 30 seconds, supporting in vivo imaging and spectroscopy applications. In vitro hydrolysis, transacetylation, and albumin binding of hyperpolarized aspirin were readily monitored in real time by 13 C-NMR spectroscopy. Hyperpolarized, double-labeled aspirin was well tolerated in mice and could be observed by both 13 C-MR imaging and 13 C-NMR spectroscopy in vivo.

The somatic mutation landscape of premalignant colorectal adenoma.

OBJECTIVE: There are few studies which characterised the molecular alterations in premalignant colorectal adenomas. Our major goal was to establish colorectal adenoma genome atlas and identify molecular markers of progression from colorectal adenoma to adenocarcinoma. DESIGN: Whole-exome sequencing and targeted sequencing were carried out in 149 adenoma samples and paired blood from patients with conventional adenoma or sessile serrated adenoma to characterise the somatic mutation landscape for premalignant colorectal lesions. The identified somatic mutations were compared with those in colorectal cancer (CRC) samples from The Cancer Genome Atlas. A supervised random forest model was employed to identify gene panels differentiating adenoma from CRC. RESULTS: Similar somatic mutation frequencies, but distinctive driver mutations, were observed in sessile serrated adenomas and conventional adenomas. The final model included 20 genes and was able to separate the somatic mutation profile of colorectal adenoma and adenocarcinoma with an area under the curve of 0.941. CONCLUSION: The findings of this project hold potential to better identify patients with adenoma who may be candidates for targeted surveillance programmes and preventive interventions to reduce the incidence of CRC.

Platelets, circulating tumor cells, and the circulome.

Platelets are cytoplasmic fragments generated by megakaryocytes in the bone marrow and do not possess a nucleus. They contribute to the "Circulome" consisting of all circulating cells, factors and macromolecules such as cfDNA. Their primary function is to recognize vascular lesions and initiate thrombus formation that ceases bleeding. This distinctive characteristic of platelets also contributes to cancer and its progression. The ability of platelets to recognize and interact with other cells and neighboring platelets enables them to interact with tumor cells in the circulation. Receptor recognition and factor mediated crosstalk between tumor cells and platelets stimulate platelet activation, release of factors, and aggregation that promotes tumor cell survival and cancer progression. This review describes platelet: (i) contributions to the "Circulome" (ii) their importance as diagnostic tools in predicting cancer risk and (iii) therapies targeting platelet activation in inhibiting tumor progression and metastasis.

Platelet "first responders" in wound response, cancer, and metastasis.

Platelets serve as "first responders" during normal wounding and homeostasis. Arising from bone marrow stem cell lineage megakaryocytes, anucleate platelets can influence inflammation and immune regulation. Biophysically, platelets are optimized due to size and discoid morphology to distribute near vessel walls, monitor vascular integrity, and initiate quick responses to vascular lesions. Adhesion receptors linked to a highly reactive filopodia-generating cytoskeleton maximizes their vascular surface contact allowing rapid response capabilities. Functionally, platelets normally initiate rapid clotting, vasoconstriction, inflammation, and wound biology that leads to sterilization, tissue repair, and resolution. Platelets also are among the first to sense, phagocytize, decorate, or react to pathogens in the circulation. These platelet first responder properties are commandeered during chronic inflammation, cancer progression, and metastasis. Leaky or inflammatory reaction blood vessel genesis during carcinogenesis provides opportunities for platelet invasion into tumors. Cancer is thought of as a non-healing or chronic wound that can be actively aided by platelet mitogenic properties to stimulate tumor growth. This growth ultimately outstrips circulatory support leads to angiogenesis and intravasation of tumor cells into the blood stream. Circulating tumor cells reengage additional platelets, which facilitates tumor cell adhesion, arrest and extravasation, and metastasis. This process, along with the hypercoagulable states associated with malignancy, is amplified by IL6 production in tumors that stimulate liver thrombopoietin production and elevates circulating platelet numbers by thrombopoiesis in the bone marrow. These complex interactions and the "first responder" role of platelets during diverse physiologic stresses provide a useful therapeutic target that deserves further exploration.

The potential role of platelets in the consensus molecular subtypes of colorectal cancer.

The consensus molecular subtypes (CMS) in colorectal cancer (CRC) represent distinct molecular subcategories of disease as reflected by comprehensive molecular profiling. The four CMS subtypes represent unique biology. CMS1 represents high immune infiltration. CMS2 demonstrates upregulation of canonical pathways such as WNT signaling. Widespread metabolic changes are seen in CMS3. CMS4 represents a mesenchymal phenotype with hallmark features including complement activation, matrix remodeling, angiogenesis, epithelial-mesechymal transition (EMT), integrin upregulation and stromal infiltration. In contrast to this new paradigm, a number of observations regarding CRC remain disconnected. Cancers are associated with thrombocytosis. Venous thromboembolic events are more likely in malignancy and may signify worse prognosis. Aspirin, an anti-platelet agent, has been linked in large observational studies to decrease incidence of adenocarcinoma and less advanced presentations of cancer, in particular CRC. Inflammatory bowel disease is a risk factor for CRC. Gross markers to recognize the immunothrombotic link such as the platelet to lymphocyte ratio are associated with poorer outcomes in many cancers. Platelets are increasingly recognized for their dual roles in coordinating the immune response in addition to hemostasis. Here, we explore how these different but related observations coalesce. Platelets, as first responders to pathogens and injury, form the link between hemostasis and immunity. We outline how platelets contribute to tumorigenesis and how some disconnected ideas may be linked through inflammation. CMS4 through its shared mechanisms has predicted platelet activation as a hallmark feature. We demonstrate a platelet gene expression signature that predicts platelet presence within CMS4 tumors.

Beyond COX-1: the effects of aspirin on platelet biology and potential mechanisms of chemoprevention.

After more than a century, aspirin remains one of the most commonly used drugs in western medicine. Although mainly used for its anti-thrombotic, anti-pyretic, and analgesic properties, a multitude of clinical studies have provided convincing evidence that regular, low-dose aspirin use dramatically lowers the risk of cancer. These observations coincide with recent studies showing a functional relationship between platelets and tumors, suggesting that aspirin's chemopreventive properties may result, in part, from direct modulation of platelet biology and biochemistry. Here, we present a review of the biochemistry and pharmacology of aspirin with particular emphasis on its cyclooxygenase-dependent and cyclooxygenase-independent effects in platelets. We also correlate the results of proteomic-based studies of aspirin acetylation in eukaryotic cells with recent developments in platelet proteomics to identify non-cyclooxygenase targets of aspirin-mediated acetylation in platelets that may play a role in its chemopreventive mechanism.

Proteomic Features of Colorectal Cancer Identify Tumor Subtypes Independent of Oncogenic Mutations and Independently Predict Relapse-Free Survival.

BACKGROUND: The directed study of the functional proteome in colorectal cancer (CRC) has identified critical protein markers and signaling pathways; however, the prognostic relevance of many of these proteins remains unclear. METHODS: We determined the prognostic implications of the functional proteome in 263 CRC tumor samples from patients treated at MD Anderson Cancer Center (MDACC) and 462 patients from The Cancer Genome Atlas (TCGA) to identify patterns of protein expression that drive tumorigenesis. A total of 163 validated proteins were analyzed by reverse phase protein array (RPPA). Unsupervised hierarchical clustering of the tumor proteins from the MDACC cohort was performed, and clustering was validated using RPPA data from TCGA CRC. Cox regression was used to identify predictors of tumor recurrence. RESULTS: Clustering revealed dichotomization, with subtype A notable for a high epithelial-mesenchymal transition (EMT) protein signature, while subtype B was notable for high Akt/TSC/mTOR pathway components. Survival data were only available for the MDACC cohort and were used to evaluate prognostic relevance of these protein signatures. Group B demonstrated worse relapse-free survival (hazard ratio 2.11, 95% confidence interval 1.04-4.27, p = 0.039), although there was no difference in known genomic drivers between the two proteomic groups. Proteomic grouping and stage were significant predictors of recurrence on multivariate analysis. Eight proteins were found to be significant predictors of tumor recurrence on multivariate analysis: Collagen VI, FOXO3a, INPP4B, LcK, phospho-PEA15, phospho-PRAS40, Rad51, phospho-S6. CONCLUSION: CRC can be classified into distinct subtypes by proteomic features independent of common oncogenic driver mutations. Proteomic analysis has identified key biomarkers with prognostic importance, however these findings require further validation in an independent cohort.

Right Versus Left Colon Cancer Biology: Integrating the Consensus Molecular Subtypes.

Although clinical management of colon cancer generally has not accounted for the primary tumor site, left-sided and right-sided colon cancers harbor different clinical and biologic characteristics. Right-sided colon cancers are more likely to have genome-wide hypermethylation via the CpG island methylator phenotype (CIMP), hypermutated state via microsatellite instability, and BRAF mutation. There are also differential exposures to potential carcinogenic toxins and microbiota in the right and left colon. Gene expression analyses further shed light on distinct biologic subtypes of colorectal cancers (CRCs), with 4 consensus molecular subtypes (CMSs) identified. Importantly, these subtypes are differentially distributed between right- and left-sided CRCs, with greater proportions of the "microsatellite unstable/immune" CMS1 and the "metabolic" CMS3 subtypes found in right-sided colon cancers. This review summarizes important biologic distinctions between right- and left-sided CRCs that likely impact prognosis and may predict for differential responses to biologic therapy. Given the inferior prognosis of stage III-IV right-sided CRCs and emerging data suggesting that anti-epidermal growth factor receptor antibody therapy is associated with worse survival in right-sided stage IV CRCs compared with left-sided cancers, these biologic differences between right- and left-sided CRCs provide critical context and may provide opportunities to personalize therapy.