Multidimensional Immunophenotyping of Intraductal Papillary Mucinous Neoplasms Reveals Novel T Cell and Macrophage Signature

BACKGROUND

Intraductal papillary mucinous neoplasms (IPMN) are the only radiographically identifiable precursor to pancreatic adenocarcinoma, yet little is known about how these lesions progress to cancer. Inflammation has been associated with dysplastic progression; however, the cause and composition of this inflammation remains poorly characterized. We sought to comprehensively profile immune cell infiltration using parallel spatial transcriptomic and flow cytometric techniques.

METHODS

Twelve patients with resected IPMN exhibiting both high-grade dysplasia (HGD) and low-grade dysplasia (LGD) were selected for spatial transcriptomics (NanoString GeoMx). Immune (CD45⁺), epithelial (PanCK⁺), and stromal (SMA⁺) compartments were analyzed separately using the GeoMx NGS Pipeline. An additional 11 patients resected for IPMN of varying degrees of dysplasia underwent immunophenotyping using flow cytometry (DURAClone IM).

RESULTS

Spatial transcriptomics revealed that T cells represent the dominant immune cell within IPMN stroma, which was confirmed by flow cytometry (56%). Spatial profiling found that the T-cell infiltrate was significantly higher in regions of LGD compared with HGD (62% vs. 50%, p = 0.038). Macrophages were the only other immune cell type with > 10% abundance, yet conversely, were generally more abundant in regions of HGD compared to LGD (19% vs. 11%, p = 0.058). Correspondingly, immune cells within regions of HGD demonstrated transcriptional upregulation of genes associated with macrophage activity including secretion (CXCL1) and phagocytosis (C1QA, C1S, C4B).

CONCLUSIONS

IPMN immune infiltrate is primarily composed of T cells and macrophages. Regions of HGD appear to be relatively deplete of T cells and show a trend toward macrophage enrichment compared with regions of LGD.

Urolithin A attenuates severity of chronic pancreatitis associated with continued alcohol intake by inhibiting PI3K/AKT/mTOR signaling

Heavy alcohol consumption is the dominant risk factor for chronic pancreatitis (CP); however, treatment and prevention strategies for alcoholic chronic pancreatitis (ACP) remains limited. The present study demonstrates that ACP induction in C57BL/6 mice causes significant acinar cell injury, pancreatic stellate cell (PSC) activation, exocrine function insufficiency, and an increased fibroinflammatory response when compared with alcohol or CP alone. Although the withdrawal of alcohol during ACP recovery led to reversion of pancreatic damage, continued alcohol consumption with established ACP perpetuated pancreatic injury. In addition, phosphokinase array and Western blot analysis of ACP-induced mice pancreata revealed activation of the phosphatidylinositol 3 kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) and cyclic AMP response element binding protein (CREB) signaling pathways possibly orchestrating the fibroinflammatory program of ACP pathogenesis. Mice treated with urolithin A (Uro A, a gut-derived microbial metabolite) in the setting of ACP with continued alcohol intake (during the recovery period) showed suppression of AKT and P70S6K activation, and acinar damage was significantly reduced with a parallel reduction in pancreas-infiltrating macrophages and proinflammatory cytokine accumulation. These results collectively provide mechanistic insight into the impact of Uro A on attenuation of ACP severity through suppression of PI3K/AKT/mTOR signaling pathways and can be a useful therapeutic approach in patients with ACP with continuous alcohol intake.NEW & NOTEWORTHY Our novel findings presented here demonstrate the utility of Uro A as an effective therapeutic agent in attenuating alcoholic chronic pancreatitis (ACP) severity with alcohol continuation after established disease, through suppression of the PI3K/AKT/mTOR signaling pathway.

Peak density of immature nerve cells occurs with high-grade dysplasia in intraductal papillary mucinous neoplasms of the pancreas

The development of neural structures within tumors is now considered vital for carcinogenesis. However, the time course of this development in human pre-invasive neoplasia has been incompletely described. Therefore, we performed a detailed analysis of nerves across the neoplastic spectrum in resected intraductal papillary mucinous neoplasms (IPMNs) of the pancreas. Histology and multiplexed immunochemistry demonstrated that nerve density increased from low-grade (LG) to high-grade dysplasia (HG) but did not further increase once invasive IPMN (INV IPMN) was present. Higher nerve density correlated with increasing expression of nerve growth factor (NGF) by the tumor cells. Intra-tumoral nerves were immature and lacked markers of sympathetic, parasympathetic, and sensory lineages. Here, we show for the first time the presence of neural precursor cells (NPCs) within the stroma of pancreatic tumors. The density of these doublecortin (DCX)-positive NPCs increased from LG to HG, but not from HG to INV IPMN. We conclude that peak neural density of tumors is reached in high-grade dysplasia (often termed carcinoma in situ) rather than after invasion. These findings suggest that nerve-tumor interactions are important in IPMN progression and may serve as the basis for future mechanistic studies and novel therapeutic modalities. © 2022 The Pathological Society of Great Britain and Ireland.

Activation of PI3K/Akt prevents hypoxia/reoxygenation-induced GnRH decline via FOXO3a

Recent studies have suggested that the hypothalamus has an important role in aging by regulating nuclear factor-κB (NF-κB)-directed gonadotropin-releasing hormone (GnRH) decline. Moreover, our previous study has shown that ischemia-reperfusion (IR) injury activates NF-κB to reduce hypothalamic GnRH release, thus suggesting that IR injury may facilitate hypothalamic programming of system aging. In this study, we further examined the role of phosphoinositide 3-kinase (PI3K)/Protein kinase B (Akt) pathway, a critical intracellular signal pathway involved in the repair process after IR, in hypoxia-reoxygenation (HR)-associated GnRH decline in vitro. We used GT1-7 cells and primarily-cultured mouse GnRH neurons as cell models for investigation. Our data revealed that the activation of the PI3K/Akt/Forkhead box protein O3a (FOXO3a) pathway protects GnRH neurons from HR-induced GnRH decline by preventing HR-induced gnrh1 gene inhibition and NF-κB activation. Our results further the understanding of the regulatory mechanisms of HR-associated hypothalamic GnRH decline.

OP0113 FUNCTIONAL GENOMICS IN PRIMARY T CELLS AND MONOCYTES IDENTIFIES MECHANISMS BY WHICH GENETIC SUSCEPTIBILITY LOCI INFLUENCE SYSTEMIC SCLEROSIS RISK

Background

Systemic sclerosis (SSc) is a complex autoimmune disease with a strong genetic component. However, the underlying mechanism by which genetics increase disease risk is still unknown. The most recent GWAS studies have identified 27 independent signals associated to SSc [1]. However, the majority of these signals affect regulatory elements that can regulate genes often located hundreds of kilobases away.

The challenge in the post-GWAS era is to use functional genomics to translate genetic findings into patients’ benefit, particularly in disease-relevant cell types.

Objectives

In this study we use chromatin conformation and gene expression analysis in patient derived primary cells and healthy individuals to assess potential mechanisms by which GWAS variants increase disease risk. We identify the potentially affected genes in a cell type specific manner and potential drug targets already in use or with potential for re-purposing.

Methods

Promoter capture Hi-C (pCHi-C) and RNA sequencing experiments were performed in a total of 15 CD4+ T cells and CD14+ monocytes samples each isolated from peripheral blood from SSc patients and healthy controls. We linked SSc-associated variants with their target genes and performed differential expression and differential interaction analyses between both cell types. Potential drug targets were identified using a protein-protein interaction model and queried against the OpenTargets database.

Results

We linked SSc-associated loci to 39 new potential target genes, confirming 7 previously assigned genes. We highlight novel causal genes, such as CXCR5 as the most probable candidate gene for the DDX6 locus (Figure 1). We confirm some previously linked SSc genes such as IRF8, STAT4, or CD247 which interestingly showed cell type specific interactions. We also identified 15 potential drug targets already in use in other similar immune-mediated diseases that could be repurposed for SSc treatment. Furthermore, we observed that interactions are directly related with the expression of important genes implicated in cell type specific pathways.

Figure 1.

Promoter Capture Hi-C interactions linking the DDX6 GWAS loci with the promoter of CXCR5 in CD4+ T cells and CD14+ monocytes. CD4+ T cells show significantly stronger interactions as well as CXCR5 gene expression.

Conclusion

Our study reveals potential causal genes for SSc-associated loci, some of them acting in a cell type specific manner, suggesting novel drug targets and biological mechanisms that may mediate SSc pathogenesis.

References

[1]López-Isac E, Acosta-Herrera M, Kerick M, et al (2019) GWAS for systemic sclerosis identifies multiple risk loci and highlights fibrotic and vasculopathy pathways. Nat Commun 10:. https://doi.org/10.1038/s41467-019-12760-y

Acknowledgements

This work was supported by the Spanish Ministry of Science and Innovation (grants RTI2018101332-B-100 and SAF2015-66761-P), the Cooperative Research Thematic Network (RETICS) programme (RD16/0012/0013) (RIER) from Instituto de Salud Carlos III (ISCIII, Spanish Ministry of Economy, Industry and Competitiveness), the Wellcome Trust (award references 207491/Z/17/Z and 215207/Z/19/Z), Versus Arthritis (award reference 21754), and the NIHR Manchester Biomedical Research Centre. DGS was supported by the Spanish Ministry of Economy and Competitiveness through the FPI programme (SAF2015-66761-P).

Disclosure of Interests

None declared

POS0035 GENE REGULATION IN T-CELLS FROM PsA PATIENTS DIFFERS BETWEEN PERIPHERAL BLOOD AND THE INFLAMED JOINTS: IMPLICATIONS FOR THE INTERPRETATION OF GWAS SIGNALS

Background

Genome-wide association studies (GWAS) have identified variants that are associated with complex diseases such as Psoriatic Arthritis (PsA). The majority of these variants do not affect the coding sequence of proteins but rather regulatory elements which are highly cell type and state specific, and can affect distally located genes via chromatin interaction mechanisms.

We and others have previously analysed GWAS loci for multiple conditions (including PsA and Rheumatoid Arthrtitis) in cell lines using functional genomics techniques, providing putative mechanisms to many loci with previously unknown function [1].

However, multiple studies have identified large differences in gene regulatory mechanisms between cell lines and primary cells, which could significantly alter the proposed mechanisms. Differences between between samples from healthy volunteers and patients, in particular from the affected tissue, have although not been exhaustively investigated.

Objectives

To assess the impact of using primary cells derived from PsA patients compared to healthy volunteers in functional genomics studies.

Methods

CD4+ and CD8+ T cells were isolated from peripherial blood from 10 healthy controls and 48 PsA patients and from 6 PsA synovial fluid samples.

We performed RNA-seq and ATAC-seq on these two cell types to analyse the global patterns of gene expression and chromatin activity.

Results

We find subtle differences between PsA patients and healthy controls in cells isolated from blood. RNA-seq analysis identified only a handful of differentially expressed genes whilst ATAC-seq analysis identified only 28 differential loci.

On the other hand, T cells isolated from synovial fluid showed significant differences compared to T cells isolated from patient’s blood. Interestingly, we find that CD4+ T cells show substantially more differentially expressed genes compared to CD8+ T cells (1168 vs 346 Log2FoldChange > 1, FDR < 0.01). Genes overexpressed in synovial CD4+ T cells are more strongly enriched for immune pathways such as cytokine signaling and T cell proliferation compared to synovial CD8+ T cells

We also find that synovial CD4+ T cells highly overexpress MHC class II genes (Figure 1).

Figure 1.

Normalized counts of the alpha chains of MHC class 2 genes in CD4+ and CD8+ T cells purified from blood from healthy subjects and patients and synovial fluid.

Conclusion

This preliminary analysis suggests that T cells isolated from peripherial blood do not seem to differ significantly between PsA patients and healthy controls. In contrast, cells isolated from synovial fluid are highly specialized and activated. Moreover, these cells do not resemble canonically activated T cells which means that this state can not be easily emulated in vitro.

This study indicates the importance of not only studying GWAS loci in relevant primary cells from patients, but also that attention needs to be given to cells isolated from the affected site.

References

[1]Shi C, Ray-Jones H, Ding J, et al (2021) Chromatin Looping Links Target Genes with Genetic Risk Loci for Dermatological Traits. J Invest Dermatol 141:1975–1984. https://doi.org/10.1016/J.JID.2021.01.015

Acknowledgements

This work was funded by the Wellcome Trust (award references 207491/Z/17/Z and 215207/Z/19/Z), the Versus Arthritis (award reference 21754), the NIHR Manchester Biomedical Research Centre, and the Medical Research Council (award reference MR/N00017X/1).

Disclosure of Interests

None declared

OP0222 IDENTIFICATION OF CAUSAL GENES AND MECHANISMS BY WHICH GENETIC VARIATION MEDIATES JUVENILE IDIOPATHIC ARTHRITIS SUSCEPTIBILITY USING FUNCTIONAL GENOMICS AND CRISPR-CAS9

Background

We recently performed the largest juvenile idiopathic arthritis (JIA) genome-wide association study (GWAS) to date 1. Disease-associated loci contain multiple single nucleotide polymorphism (SNPs), and the majority map to non-coding enhancers, making it challenging to define causal variants and genes.

Functional genomics datasets in disease-relevant tissues have shown to be essential for the functional interpretation of GWAS loci. In particular, capture Hi-C (CHi-C) has been successful in detecting chromosomal interactions linking GWAS loci to their target genes. However, such datasets are lacking in JIA.

Objectives

The aim of this study is to bridge this gap and advance the knowledge of the biological mechanisms that underpin susceptibility to JIA, by integrating GWAS with public epigenomics datasets and in-house generated CHi-C from JIA patients. We focus on CD4+ T-cells, which have been shown to be one of the most relevant cell types in JIA. In addition, we use CRISPR-Cas9 to validate the regulatory effect of prioritised variants on their predicted target genes.

Methods

Credible SNP sets for the top JIA risk loci (P < 5x10-6) were annotated using EpiMap data 2. Low input whole genome promoter CHi-C (PCHi-C) was performed on CD4+ T-cells isolated from blood from 3 JIA oligoarthritis patients, and data was analysed using CHiCAGO 3. GWAS and PCHi-C data were combined to prioritise causal genes using the Capture Hi-C Omnibus Gene Score (COGS) pipeline 4. We subsequently employed CRISPR activation (CRISPRa) and CRISPR interference (CRISPRi) in Jurkats to assess whether prioritized JIA variants were capable of regulating the expression of the interacting genes.

Results

614 credible SNPs (out of 735) were found to overlap active enhancers in CD4+ T-cells, and were prioritized for further analysis.

We identified numerous significant chromatin interactions in 19 out of 44 non-MHC JIA associated loci, linking JIA SNPs mapping to T-cell enhancers to a total of 61 target genes and revealing potential novel disease pathways. Moreover, COGS prioritised a total of 7 genes (RGS14, ERAP2, HIPK1, CCR4, CCRL2, CCR2, CCR3).

A JIA associated locus on chromosome 3 contains 39 SNPs. It maps to an intergenic region and the causal gene/s are unclear. Our PCHi-C data revealed that this JIA locus presents chromatin interactions with the promoters of several genes, such as CCRL2, CCR2, CCR3 and CCR5, three of which were prioritised by COGS. Two variants were selected for further analysis: rs79815064, which had the highest posterior probability, and rs8005404,the only variant within a CD4+ T-cell enhancer linked to surrounding gene activity.

When both SNPs were targeted with CRISPRa and CRISPRi, we observed an increased and decreased expression, respectively, of CCRL2, CCR2, CCR3 and CCR5, confirming their role in disease. These genes belong to the chemokine receptor family and are important regulators of the inflammatory response.

Conclusion

Our work shows how functional genomics can help identify biological mechanisms by which GWAS variants increase risk of JIA, which in turn will benefit patients through personalised medicine and the identification of therapeutic targets.

References

[1]López-Isac, E. et al. Combined genetic analysis of juvenile idiopathic arthritis clinical subtypes identifies novel risk loci, target genes and key regulatory mechanisms. Ann. Rheum. Dis.80, 321–328 (2021).

[2]Boix, C. A., James, B. T., Park, Y. P., Meuleman, W. & Kellis, M. Regulatory genomic circuitry of human disease loci by integrative epigenomics. Nat. 2021 5907845590, 300–307 (2021).

[3]Cairns, J. et al. CHiCAGO: Robust detection of DNA looping interactions in Capture Hi-C data. Genome Biol.17, 1–17 (2016).

[4]Javierre, B. M. et al. Lineage-Specific Genome Architecture Links Enhancers and Non-coding Disease Variants to Target Gene Promoters. Cell167, 1369 (2016).

Disclosure of Interests

Antonio Frantzesko: None declared, Valeriya Malysheva: None declared, Chenfu Shi: None declared, James Ding: None declared, John Bowes: None declared, Wendy Thomson: None declared, Stephen Eyre: None declared, Mikhail Spivakov Shareholder of: co-founder and shareholder of Enhanc3D Genomics Ltd, Gisela Orozco: None declared

A High Energy X-ray Diffraction Study of Amorphous Indomethacin

Amorphous pharmaceuticals often possess a wide range of molecular conformations and bonding arrangements. The x-ray pair distribution function (PDF) method is a powerful technique for the characterization of variations in both intra-molecular and inter-molecular packing arrangements. Here, the x-ray PDF of amorphous Indomethacin is shown to be particularly sensitive to the preferred orientations of the chlorobenzyl ring found in isomers in the crystalline state. In some cases, the chlorobenzyl ring has no preferred torsional angle in the amorphous form, while in others evidence of distinct isomer orientations are observed. Amorphous samples with no preferred torsion angles of the chlorobenzyl ring are found to favor enhanced inter-molecular hydrogen bonding, and this is reflected in the intensity of the first sharp diffraction peak. These significant variations in structure rule out amorphous Indomethacin as a possible standard for x-ray PDF measurements. At high humidity, time resolved PDF's for >40 h reveal water molecules forming hydrogen bonds with Indomethacin molecules. A simple linear hydrogen bond model indicates that water molecules in the wet amorphous form have similar hydrogen bond strengths to those found between Indomethacin dimers or chains in the dry amorphous form.

Data Set for Reporting Carcinoma of the Stomach in Gastrectomy

Context.—

A standardized detailed surgical pathology report is the cornerstone of gastric cancer management.

Objective.—

To guide management and prognostication for patients with gastric carcinomas globally, the International Collaboration on Cancer Reporting aimed to produce an evidence-based international pathology reporting data set with a panel of globally recognized expert pathologists and clinicians.

Design.—

Based on published guidelines/data sets for gastric carcinomas, a working draft was developed by the chair of the expert panel of pathologists and clinicians. The draft was then circulated to the panel and discussed in a series of teleconferences and email communications until consensus was achieved. The draft data set was uploaded on the International Collaboration on Cancer Reporting Web site for public comment. The data set was reviewed in consideration of the feedback, and a final version was approved by the panel.

Results.—

This data set was developed for gastrectomy specimens for primary gastric carcinomas, including neuroendocrine carcinomas and mixed neuroendocrine-nonneuroendocrine neoplasms. Well-differentiated neuroendocrine tumors, nonepithelial malignancies, and secondary tumors were excluded from this data set. The final data set contains 15 core (required) elements and 8 noncore (recommended) elements. A commentary is provided for each element.

Conclusions.—

The International Collaboration on Cancer Reporting has published freely available, evidence-based data sets for gastric cancer reporting. Standardized reporting has been shown to improve patient care and facilitates data exchange and analysis for quality assurance, cancer epidemiology, and clinical and basic research.

Primary hepatic neoplasms arising in cirrhotic livers can have a variable spectrum of neuroendocrine differentiation

Primary hepatic neoplasms with neuroendocrine differentiation are extremely rare. Their clinicopathological features and molecular genetic basis are largely unknown. We identified four cases of primary hepatic neoplasms with neuroendocrine differentiation. Electronic medical records were reviewed for clinical history, imaging findings, laboratory results, and follow-up. Pathology slides, immunohistochemistry, and ancillary studies were reviewed. There were two females and two males with age ranging from 52 to 74 years. There was one amphicrine carcinoma with tumor cells simultaneously demonstrating both hepatocellular and neuroendocrine differentiation, one mixed hepatocellular-neuroendocrine carcinoma (NEC) with hepatocellular component intermingled with neuroendocrine component, one small cell NEC, and one well-differentiated neuroendocrine tumor. Next- generation sequencing of the mixed hepatocellular-NEC and small cell NEC showed molecular/genetic alterations commonly seen in hepatocellular carcinoma (HCC). All four cases arose in a background of cirrhosis. Primary hepatic neoplasms arising in cirrhotic livers can have a spectrum of neuroendocrine differentiation. Presence of a NEC component may be an indicator of aggressiveness. In addition, primary hepatic carcinomas with neuroendocrine differentiation likely share the same molecular pathways as HCC.

Dataset for the reporting of carcinoma of the esophagus in resection specimens: recommendations from the International Collaboration on Cancer Reporting

BACKGROUND AND OBJECTIVES

A standardized data set for esophageal carcinoma pathology reporting was developed based on the approach of the International Collaboration on Cancer Reporting (ICCR) for the purpose of improving cancer patient outcomes and international benchmarking in cancer management.

MATERIALS AND METHODS

The ICCR convened a multidisciplinary international expert panel to identify the best evidence-based clinical and pathological parameters for inclusion in the data set for esophageal carcinoma. The data set incorporated the current edition of the World Health Organization Classification of Tumours of the Digestive System, and Tumour-Node-Metastasis staging systems.

RESULTS

The scope of the data set encompassed resection specimens of the esophagus and esophagogastric junction with tumor epicenter ≤20 mm into the proximal stomach. Core reporting elements included information on neoadjuvant therapy, operative procedure used, tumor focality, tumor site, tumor dimensions, distance of tumor to resection margins, histological tumor type, presence and type of dysplasia, tumor grade, extent of invasion in the esophagus, lymphovascular invasion, response to neoadjuvant therapy, status of resection margin, ancillary studies, lymph node status, distant metastases, and pathological staging. Additional non-core elements considered useful to report included clinical information, specimen dimensions, macroscopic appearance of tumor, and coexistent pathology.

CONCLUSIONS

This is the first international peer-reviewed structured reporting data set for surgically resected specimens of the esophagus. The ICCR carcinoma of the esophagus data set is recommended for routine use globally and is a valuable tool to support standardized reporting, to benefit patient care by providing diagnostic and prognostic best-practice parameters.

[Value of the application of enhanced CT radiomics and machine learning in preoperative prediction of microvascular invasion in hepatocellular carcinoma]

Objective: To explore the value of machine learning models in preoperative prediction of microvascular invasion (MVI) in hepatocellular carcinoma (HCC) based on dual-phase contrast-enhanced CT radiomics features. Methods: The data of 148 patients [106 males and 42 females, with an average age of (58±11) years] with HCC confirmed by pathology in the First Affiliated Hospital of Soochow University from January 2015 to May 2020 were retrospectively analyzed, including 88 cases of positive MVI and 60 cases of negative MVI. According to the ratio of 7∶3, the patients were randomly divided into the training and validation sets, respectively. The three-dimensional (3D) radiomics features of HCC in arterial phase (AP) and portal venous phase (PP) were extracted by MaZda software, and the optimal feature subset was obtained by combining three feature selection methods (FPM method) and Lasso regression. Then, six machine learning methods were used to build the prediction models. Receiver operating characteristic (ROC) curves were drawn to evaluate the prediction ability of the aforementioned models, and the area under the curve (AUC), accuracy, sensitivity and specificity were calculated. Results: Radiomics features of HCC in AP and PP were extracted by MaZda software, with 239 in each phase. There were 7 optimal features in AP and 14 optimal features in PP selected by FPM method and Lasso regression, respectively. The AUCs of decision tree, extreme gradient boosting, random forest, support vector machine (SVM), generalized linear model, and neural network based on the 7 optimal features in AP in the validation set were 0.736, 0.910, 0.913, 0.915, 0.897, 0.648, respectively. The SVM had the highest AUC in the validation set, with the accuracy, sensitivity and specificity of 95.35%, 95.83% and 94.74%, respectively. Likewise, the AUCs of machine learning models in prediction of MVI in HCC based on the 14 optimal features in PP in the validation set were 0.873, 0.876, 0.913, 0.859, 0.877, 0.834, respectively, and there were no significant differences (all P>0.05). The random forest had the highest AUC in the validation set, with the accuracy, sensitivity and specificity of 90.70%, 87.50% and 94.74%, respectively. Conclusion: Machine learning models based on dual-phase enhanced CT radiomics features can be used in preoperative prediction of MVI in HCC, particularly the SVM and random forest models have high prediction efficiency.

Colonic Epithelial-Derived Selenoprotein P Is the Source for Antioxidant-Mediated Protection in Colitis-Associated Cancer

BACKGROUND & AIMS

Patients with inflammatory bowel disease (IBD) demonstrate nutritional selenium deficiencies and are at greater risk of developing colon cancer. Previously, we determined that global reduction of the secreted antioxidant selenium-containing protein, selenoprotein P (SELENOP), substantially increased tumor development in an experimental colitis-associated cancer (CAC) model. We next sought to delineate tissue-specific contributions of SELENOP to intestinal inflammatory carcinogenesis and define clinical context.

METHODS

Selenop floxed mice crossed with Cre driver lines to delete Selenop from the liver, myeloid lineages, or intestinal epithelium were placed on an azoxymethane/dextran sodium sulfate experimental CAC protocol. SELENOP loss was assessed in human ulcerative colitis (UC) organoids, and expression was queried in human and adult UC samples.

RESULTS

Although large sources of SELENOP, both liver- and myeloid-specific Selenop deletion failed to modify azoxymethane/dextran sodium sulfate-mediated tumorigenesis. Instead, epithelial-specific deletion increased CAC tumorigenesis, likely due to elevated oxidative stress with a resulting increase in genomic instability and augmented tumor initiation. SELENOP was down-regulated in UC colon biopsies and levels were inversely correlated with endoscopic disease severity and tissue S100A8 (calprotectin) gene expression.

CONCLUSIONS

Although global selenium status is typically assessed by measuring liver-derived plasma SELENOP levels, our results indicate that the peripheral SELENOP pool is dispensable for CAC. Colonic epithelial SELENOP is the main contributor to local antioxidant capabilities. Thus, colonic SELENOP is the most informative means to assess selenium levels and activity in IBD patients and may serve as a novel biomarker for UC disease severity and identify patients most predisposed to CAC development.

LncRNA OTUD6B-AS1 inhibits many cellular processes in colorectal cancer by sponging miR-21-5p and regulating PNRC2

Accumulating evidence has revealed that long noncoding RNAs (lncRNAs) play essential roles in regulating cellular process of various cancers. There have been many studies on the biological functions of lncRNAs in colorectal cancer (CRC). In this research, we explored the role and mechanism of lncRNA ovarian tumor domain containing 6B antisense RNA1 (OTUD6B-AS1) in CRC. Here, we detected OTUD6B-AS1 expression in CRC tissues and cells by RT-qPCR. Functional experiments were performed to test alterations in different cellular processes. Moreover, to verify the binding ability among the indicated RNA molecules, we carried out RIP, RNA pull-down and luciferase reporter assays. According to our data, OTUD6B-AS1 expression was low in CRC tissues and cells. Functionally, overexpression of OTUD6B-AS1 inhibited cell proliferation, migration, invasion and EMT, and promoted cell apoptosis. Bioinformatic analysis and mechanistical experiments confirmed that OTUD6B-AS1 could act as a competitive endogenous RNA (ceRNA) to upregulate Proline-Rich Nuclear Receptor Coactivator 2 (PNRC2) expression by sequestering miR-21-5p. Further rescue experiments validated the inhibitory function of the OTUD6B-AS1/miR-21-5p/PNRC2 axis in cellular process of CRC. Overall, OTUD6B-AS1 inhibits cellular development in CRC by sponging miR-21-5p and upregulating PNRC2, providing a novel insight into the exploration on CRC treatment.