Mucin 21 is a key molecule involved in the incohesive growth pattern in lung adenocarcinoma

Upper Airway Epithelial Tissue Transcriptome Analysis Reveals Immune Signatures Associated with COVID-19 Severity in Ghanaians

The immunological signatures driving the severity of coronavirus disease 19 (COVID-19) in Ghanaians remain poorly understood. We performed bulk transcriptome sequencing of nasopharyngeal samples from severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-infected Ghanaians with mild and severe COVID-19, as well as healthy controls to characterize immune signatures at the primary SARS-CoV-2 infection site and identify drivers of disease severity. Generally, a heightened antiviral response was observed in SARS-CoV-2-infected Ghanaians compared with uninfected controls. COVID-19 severity was associated with immune suppression, overexpression of proinflammatory cytokines, including CRNN, IL1A, S100A7, and IL23A, and activation of pathways involved in keratinocyte proliferation. SAMD9L was among the differentially regulated interferon-stimulated genes in our mild and severe disease cohorts, suggesting that it may play a critical role in SARS-CoV-2 pathogenesis. By comparing our data with a publicly available dataset from a non-African (Indians) (GSE166530), an elevated expression of antiviral response-related genes was noted in COVID-19-infected Ghanaians. Overall, the study describes immune signatures driving COVID-19 severity in Ghanaians and identifies immune drivers that could serve as potential prognostic markers for future outbreaks or pandemics. It further provides important preliminary evidence suggesting differences in antiviral response at the upper respiratory interface in sub-Saharan Africans (Ghanaians) and non-Africans, which could be contributing to the differences in disease outcomes. Further studies using larger datasets from different populations will expand on these findings.

A CRISPR activation screen identifies MUC-21 as critical for resistance to NK and T cell-mediated cytotoxicity

BACKGROUND

Immunotherapy has significantly advanced cancer treatments, but many patients do not respond to it, partly due to immunosuppressive mechanisms used by tumor cells. These cells employ immunosuppressive ligands to evade detection and elimination by the immune system. Therefore, the discovery and characterization of novel immunosuppressive ligands that facilitate immune evasion are crucial for developing more potent anti-cancer therapies.

METHODS

We conducted gain-of-function screens using a CRISPRa (CRISPR activation) library that covered the entire human transmembrane sub-genome to identify surface molecules capable of hindering NK-mediated cytotoxicity. The immunosuppressive role and mechanism of MUC21 were validated using NK and T cell mediated cytotoxicity assays. Bioinformatics tools were employed to assess the clinical implications of mucin-21 (MUC21) in cancer cell immunity.

RESULTS

Our genetic screens revealed that MUC21 expression on cancer cell surfaces inhibits both the cytotoxic activity of NK cells and antibody-dependent cellular cytotoxicity, but not affecting complement-dependent cytotoxicity. Additionally, MUC21 expression hinders T cell activation by impeding antigen recognition, thereby diminishing the effectiveness of the immune checkpoint inhibitor, anti-PD-L1. Moreover, MUC21 expression suppress the antitumor function of both CAR-T cells and CAR-NK cells. Mechanistically, MUC21 facilitates immune evasion by creating steric hindrance, preventing interactions between cancer and immune cells. Bioinformatics analysis revealed elevated MUC21 expression in lung cancer, which correlated with reduced infiltration and activation of cytotoxic immune cells. Intriguingly, MUC21 expression was higher in non-small cell lung cancer (NSCLC) tumors that were non-responsive to anti-PD-(L)1 treatment compared to responsive tumors.

CONCLUSIONS

These findings indicate that surface MUC21 serves as a potent immunosuppressive ligand, shielding cancer cells from NK and CD8+T cell attacks. This suggests that inhibiting MUC21 could be a promising strategy to improve cancer immunotherapy.

The manipulation of cell suspensions from zebrafish intestinal mucosa contributes to understanding enteritis

Background

Although zebrafish are commonly used to study intestinal mucosal immunity, no dedicated procedure for isolating immune cells from zebrafish intestines is currently available. A speedy and simple operating approach for preparing cell suspension from mucosa has been devised to better understanding of intestinal cellular immunity in zebrafish.

Methods and results

The mucosal villi were separated away from the muscle layer by repeated blows. The complete deprivation of mucosa was done and evidenced by HE and qPCR results. Higher expression of both innate (mpeg1, mpx, and lck) and adaptive immune genes (zap70, blnk, foxp3a, and foxp3b) was revealed compared to cells obtained by typical mesh rubbing. The cytometric results also revealed that the tested operation group had a higher concentration and viability. Further, fluorescent-labelled immune cells from 3mo Tg(lyz:DsRED2), Tg(mpeg1:EGFP), Tg(Rag2:DsRED), and Tg(lck:EGFP), were isolated and evaluated for the proportion, and immune cells' type could be inferred from the expression of marker genes. The transcriptomic data demonstrated that the intestinal immune cell suspension made using the new technique was enriched in immune-related genes and pathways, including il17a/f, il22, cd59, and zap70, as well as pattern recognition receptor signaling and cytokine-cytokine receptor interaction. In addition, the low expression of DEG for the adherent and close junctions indicated less muscular contamination. Also, lower expression of gel-forming mucus-associated genes in the mucosal cell suspension was consistent with the current less viscous cell suspension. To apply and validate the developed manipulation, enteritis was induced by soybean meal diet, and immune cell suspensions were analyzed by flow cytometry and qPCR. The finding that in enteritis samples, there was inflammatory increase of neutrophils and macrophages, was in line with upregulated cytokines (il8 and il10) and cell markers (mpeg1 and mpx).

Conclusion

As a result, the current work created a realistic technique for studying intestinal immune cells in zebrafish. The immune cells acquired may aid in further research and knowledge of intestinal illness at the cellular level.

Integrating Expression Data-Based Deep Neural Network Models with Biological Networks to Identify Regulatory Modules for Lung Adenocarcinoma

Simple Summary

The growing evidence suggested that competing endogenous RNAs (ceRNAs) have significant associations with tumor occurrence and progression, yet the regulatory mechanism of them in lung adenocarcinoma remains unclear. Identification of the regulatory modules for lung adenocarcinoma is a critical and fundamental step towards understanding the regulatory mechanisms during carcinogenesis. Deep neural network (DNN) models have become a powerful tool to intelligently recognize the sophisticated relationships of ceRNAs appropriately. In this paper, multiple deep neural network models were constructed using the expression data to identify regulatory modules for lung adenocarcinoma in biological networks. Three identified regulatory modules association with lung adenocarcinoma were validated from three aspects, i.e., literature review, functional enrichment analysis, and an independent dataset. The regulatory relationships between RNAs were validated in various datasets, including CPTAC, TCGA and an expression profile from the GEO database. Our study will contribute to improving the understanding of regulatory mechanisms in the carcinogenesis of lung adenocarcinoma and provide schemes for identifying novel regulatory modules of other cancers.

Abstract

Lung adenocarcinoma is the most common type of primary lung cancer, but the regulatory mechanisms during carcinogenesis remain unclear. The identification of regulatory modules for lung adenocarcinoma has become one of the hotspots of bioinformatics. In this paper, multiple deep neural network (DNN) models were constructed using the expression data to identify regulatory modules for lung adenocarcinoma in biological networks. First, the mRNAs, lncRNAs and miRNAs with significant differences in the expression levels between tumor and non-tumor tissues were obtained. MRNA DNN models were established and optimized to mine candidate mRNAs that significantly contributed to the DNN models and were in the center of an interaction network. Another DNN model was then constructed and potential ceRNAs were screened out based on the contribution of each RNA to the model. Finally, three modules comprised of miRNAs and their regulated mRNAs and lncRNAs with the same regulation direction were identified as regulatory modules that regulated the initiation of lung adenocarcinoma through ceRNAs relationships. They were validated by literature and functional enrichment analysis. The effectiveness of these regulatory modules was evaluated in an independent lung adenocarcinoma dataset. Regulatory modules for lung adenocarcinoma identified in this study provided a reference for regulatory mechanisms during carcinogenesis.

Expression of Mucin Family Proteins in Non-Small-Cell Lung Cancer and its Role in Evaluation of Prognosis

Lung cancer is still the major contributor to cancer-related mortality. Over 85% of patients suffer from non-small-cell lung cancer (NSCLC). Mucins (MUCs) are large glycoproteins secreted or membrane-bound produced by epithelial cells in normal and malignant tissues. They are the major components of the mucous gel that covers the surface of the respiratory epithelium. Certain MUCs have been used or proposed to act as biomarkers for lung cancer. Nevertheless, the expression, messenger ribonucleic acid (mRNA) levels, and the prognostic value of MUCs in NSCLC are yet to be investigated systematically. In this research, the biological information of MUC proteins in patients with NSCLC was examined using a series of databases. The results based on gene expression profiling interactive analysis (GEPIA) illustrated that the expression of MUC3A, MUC4, MUC5B, MUC13, MUC16, and MUC21 mRNAs was remarkably upmodulated in lung adenocarcinoma (LUAD) patients, whereas the MUC1 expression was downregulated in lung squamous cell carcinoma (LUSC) patients. Kaplan–Meier plotter (KM Plotter) analysis revealed that elevated mRNA expression levels of MUC3A and MUC16 were linked to unfavourable overall survival (OS) in NSCLC, while increased mRNA expression of MUC1 and MUC15 was linked to good OS, especially in LUAD patients. In addition, differential expression of MUC1, MUC3A/3B, MUC8, MUC12, MUC15, and MUC16 mRNA was linked to the prognoses of NSCLC patients with varied clinical-pathological subtypes. Genetic alterations of MUCs in NSCLC primarily involved mutations, fusion, amplification, deep deletion, and multiple alterations according to cancer genomics (cBioPortal). Therefore, we propose that combinations of MUC proteins can act as prognostic biomarkers and demonstrate the therapeutic potential for NSCLC-related therapy.

The prognostic influence of histological subtypes of micropapillary tumors on patients with lung adenocarcinoma ≤ 2 cm

Objective

This study aimed to explore the value of micropapillary histological subtypes in predicting the specific surgical specificity and lymph node metastasis prognosis of early lung adenocarcinoma.

Methods

A total of 390 patients with lung adenocarcinoma were included who underwent surgery in the Department of Thoracic Surgery of the Affiliated Provincial Hospital of Anhui Medical University from January 2016 to December 2017. The data were analysed with SPSS 26.0 statistical software, and the clinicopathological data of the two groups were compared with the chi-square test. The survival rate was calculated by the Kaplan-Meier method, and the difference in survival rate between groups was analysed by the log-rank test. Multivariate survival analysis was performed using the Cox model.

Results

Univariate analysis of the clinicopathological data of the patients showed that the micropapillary histological subtype was significantly associated with the survival rate of patients (p=0.007). The clinicopathological data of the patients were substituted into the Cox model for multivariate analysis, and the results showed that the micropapillary histological subtype was an independent prognostic factor affecting the survival rate of the patients (p=0.009).The average survival time of Group A (micronipple composition > 5%) was 66.7 months; the 1-year, 3-year, and 5-year survival rates were 98.8%, 93.0%, and 80.9%, respectively.The survival of the lobectomy group was better than that of the sublobectomy group and the survival of patients with systematic dissection was better than that of patients with limited lymph node dissection. The average survival time of Group B (micronipple composition ≤ 5%) was 70.5 months; the 1-year, 3-year, and 5-year survival rates were 99.3%, 95.4%, and 90.6%, respectively. There was no difference in the survival rate between the lobectomy group and sublobectomy group, and there was also no difference in survival between systematic lymph node dissection and limited lymph node dissection, The survival rate of Group B was significantly better than that of Group A.

Conclusion

The micropapillary histological component is an independent risk factor after surgery in patients with ≤2 cm lung adenocarcinoma. When the proportion of micropapillary components is different, the prognosis of patients is different when different surgical methods and lymph node dissections are performed. Lobectomy and systematic lymph node dissection are recommended for patients with a micropapillary histological composition >5%; sublobar resection and limited lymph node dissection are recommended for patients with a micropapillary histological composition ≤5%.

Unique Glycoform-Dependent Monoclonal Antibodies for Mouse Mucin 21

Mucin 21(Muc21)/epiglycanin is expressed on apical surfaces of squamous epithelia and has potentially protective roles, which are thought to be associated with its unique glycoforms, whereas its aberrant glycosylation is implicated in the malignant behaviors of some carcinomas. Despite the importance of glycoforms, we lack tools to detect specific glycoforms of mouse Muc21. In this study, we generated two monoclonal antibodies (mAbs) that recognize different glycoforms of Muc21. We used membrane lysates of Muc21-expressing TA3-Ha cells or Chinese hamster ovary (CHO)-K1 cells transfected with Muc21 as antigens. Specificity testing, utilizing Muc21 glycosylation variant cells, showed that mAb 1A4-1 recognized Muc21 carrying glycans terminated with galactose residues, whereas mAb 18A11 recognized Muc21 carrying sialylated glycans. mAb 1A4-1 stained a majority of mouse mammary carcinoma TA3-Ha cells in vitro and in engrafted tumors in mice, whereas mAb 18A11 recognized only a subpopulation of these. mAb 1A4-1 was useful in immunohistochemically detecting Muc21 in normal squamous epithelia. In conclusion, these mAbs recognize distinct Muc21 epitopes formed by combinations of peptide portions and O-glycans.

Mucin 21 confers resistance to apoptosis in an O-glycosylation-dependent manner

Highly glycosylated mucins protect epithelial surfaces from external insults and are related to malignant behaviors of carcinoma cells. However, the importance of carbohydrate chains on mucins in the process of cellular protection is not fully understood. Here, we investigated the effect of human mucin-21 (MUC21) expression on the susceptibility to apoptosis. MUC21 transfection into HEK293 cells decreased the number of apoptotic cells in culture media containing etoposide or after ultraviolet light irradiation. We used Chinese hamster ovary (CHO) cell variants to investigate the importance of MUC21 glycosylation in the resistance to apoptosis. When MUC21 was expressed in CHO-K1 cells, it was glycosylated with sialyl T-antigen and the cells showed resistance to etoposide-induced apoptosis. MUC21 transfection into Lec2 cells, a variant of CHO cells lacking sialylation of glycans, revealed that the presence of nonsialylated T-antigen also renders cells resistant to etoposide-induced apoptosis. MUC21 was transfected into ldlD cells and the glycosylation was manipulated by supplementation to the medium. Nonsupplemented cells and cells supplemented with N-acetylgalactosamine showed no resistance to etoposide-induced apoptosis. In contrast, these cells supplemented with N-acetylgalactosamine plus galactose expressed sialyl T-antigen and exhibited resistance to etoposide-induced apoptosis. Finally, galectin-3 knockdown in MUC21 transfectants of HEK293 cells did not significantly affect MUC21-dependent induction of apoptosis resistance. The results suggest that T-antigen with or without sialic acid is essential to the antiapoptotic effect of MUC21.

Mucin 21 (MUC21) is a large glycoprotein that protects squamous epithelia. Glycan changes in mucins occur in cancer cells and are thought to contribute to malignant progression. We report glycoform-dependent antiapoptotic effects of MUC21. Various MUC21 glycoforms were expressed in HEK293 and CHO cells. Apoptosis was induced using etoposide or UV exposure. MUC21 with glycans terminated with galactose/sialic acid inhibited apoptosis; MUC21 with no glycans or N-acetylgalactoseamine did not.

MUC21 induces the viability and migration of glioblastoma via the STAT3/AKT pathway

Glioblastoma (GBM) is a malignant tumor with one of the fastest increasing morbidity and mortality rates. As such, more therapeutic targets need to be developed to combat this disease. Mucin 21 (MUC21) is a human counterpart of mouse epiglycanin and mediates multiple cellular functions. However, its possible effects on GBM and its possible mechanism remain unclear. The current study aimed to clarify the role or MUC21 in the progression of GBM by performing a series of in vitro assays, including Cell Counting Kit-8, colony formation, wound closure, transwell, and in vivo assays. In the present study, the aberrantly high expression of MUC21 in human GBM tissues and cell lines was observed and it was revealed that it was associated with the clinicopathological feature, tumor recurrence, in patients with GBM. MUC21 promoted the viability and motility of GBM cells in vitro and stimulated tumor growth in vivo. It was further confirmed that MUC21 promoted the progression of GBM via the STAT3/AKT pathway and it was considered that MUC21 could serve as a promising target for the treatment of GBM.

Gene expression profiling using targeted RNA-sequencing to elucidate the progression from histologically normal lung tissues to non-invasive lesions in invasive lung adenocarcinoma

Lung adenocarcinoma (LUAD) shows heterogeneous morphological features and the stepwise progression from adenocarcinoma in situ to minimally invasive adenocarcinoma to invasive LUAD. Although multiple genetic alterations have been linked to the progression, the differences between the gene expression profiles of non-invasive lesions (non-ILs) and adjacent histologically normal lung (aNL) tissues within invasive LUAD have not been investigated. Herein, we analyzed differentially expressed genes (DEGs) specific to early-stage carcinogenesis in LUAD. Invasive LUAD tissue samples containing both non-ILs and aNL tissues were obtained from seven patients with pathological stage I LUAD, and each component was subjected to microdissection. Gene expression profiles of each component were determined using targeted RNA-sequencing. In total, 2536 DEGs, including 863 upregulated and 1673 downregulated genes, were identified in non-ILs. In non-ILs, the expression of SLC44A5, a choline transporter-like protein-coding gene, was significantly upregulated, and that of TMEM100, a gene encoding a transmembrane protein, was significantly downregulated. Reportedly, SLC44A5 plays an important role in the development and progression of hepatocellular carcinoma, whereas TMEM100 functions as a tumor suppressor in non-small cell lung cancer. Gene set enrichment analysis showed that DEGs in non-ILs were negatively enriched in cell death and immune response. Immunohistochemical analysis revealed that increased SLC44A5 expression and decreased TMEM100 expression were maintained in ILs. A protein-protein interaction (PPI) network analysis identified several upregulated and downregulated hub genes with high degrees in non-ILs. In conclusion, several new DEGs and key PPI network hub genes were identified in non-ILs, contributing to understanding of early-stage carcinogenesis in LUAD.

Differential MUC22 expression by epigenetic alterations in human lung squamous cell carcinoma and adenocarcinoma

Disruption in mucins (MUCs) is involved in cancer development and metastasis and is thus used as a biomarker. Non‑small cell lung carcinoma (NSCLC) is characterized by heterogeneous genetic and epigenetic alterations. Lung adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC) are the two primary subtypes of NSCLC that require different therapeutic interventions. Here, we report distinct expression and epigenetic alterations in mucin 22 (MUC22), a new MUC family member, in LUSC vs. LUAD. In lung cancer cell lines and tissues, MUC22 was downregulated in LUSC (MUC22^Low) but upregulated in LUAD (MUC22^High) with co‑expression of MUC21. The aberrant expression of MUC22 was inversely correlated with its promoter hypermethylation in LUSC and hypomethylation in LUAD cells and tissues, respectively. Decreased MUC22 expression in NSCLC cell lines was restored upon treatment with epigenetic modifiers 5‑aza‑2'‑deoxycytidine (5‑Aza) or trichostatin A (TSA), accompanied by reduction in global protein level of histone deacetylase 1 (HDAC1) but increased enrichment of histone H3 lysine 9 acetylation (H3K9ac) specifically in the MUC22 promoter in the SK‑MES‑1 cell line. MUC22 knockdown increased the growth and motility of lung cancer cells and an immortalized human bronchial epithelial BEAS‑2B cell line via NF‑κB activation. Clinically, MUC22^Low in LUSC and MUC22^High in LUAD were shown to be indicators of unfavorable overall survival for patients with early cancer stages. Our study reveals that changes in MUC22 expression due to epigenetic alterations in NSCLC may have important biological significance and prognostic potential in LUSC when compared to LUAD. Thus, MUC22 expression and epigenetic alterations may be used for molecular subtyping of NSCLC in precision medicine.

Integrative RNA-Seq and H3 Trimethylation ChIP-Seq Analysis of Human Lung Cancer Cells Isolated by Laser-Microdissection

Simple Summary

Tissue heterogeneity is one of the major problems in cancer genomics. Thus, we developed and conducted an RNA-Seq and ChIP-Seq integrative analysis of clinical lung tissue samples with the isolation of specific cell populations using laser-microdissection microscopy (LMD). The transcriptomic profile was successfully captured and somatically altered regions marked by histone H3 lysine 4 trimethylation (H3K4me3) were identified in lung cancer. We also observed the differential expressions of cancer-related genes near the altered proximal H3K4me3 regions, while altered distal H3K4me3 regions were overlapped with enhancer activity annotations of cancer regulatory genes. Additionally, proximal tumor-gained promoters were associated with the core components of polycomb repressive complex 2. Our study demonstrates the practical workflow of using LMD on clinical samples for integrative analyses, which improves the overall understanding of genetic and epigenetic dysregulation of malignancy.

Abstract

Our previous integrative study in gastric cancer discovered cryptic promoter activation events that drive the expression of important developmental genes. However, it was unclear if such cancer-associated epigenetic changes occurred in cancer cells or other cell types in bulk tissue samples. An integrative analysis consisting of RNA-Seq and H3K4me3 ChIP-Seq was used. This workflow was applied to a set of matched normal lung tissues and non-small cell lung cancer (NSCLC) tissues, for which the stroma and tumor cell parts could be isolated by laser-microdissection microscopy (LMD). RNA-Seq analysis showed subtype-specific differential expressed genes and enriched pathways in NSCLC. ChIP-Seq analysis results suggested that the proximal altered H3K4me3 regions were located at differentially expressed genes involved in cancer-related pathways, while altered distal H3K4me3 regions were annotated with enhancer activity of cancer regulatory genes. Interestingly, integration with ENCODE data revealed that proximal tumor-gained promoters were associated with EZH2 and SUZ12 occupancies, which are the core components of polycomb repressive complex 2 (PRC2). This study used LMD on clinical samples for an integrative analysis to overcome the tissue heterogeneity problem in cancer research. The results also contribute to the overall understanding of genetic and epigenetic dysregulation of lung malignancy.

RNA sequencing identifies transcriptional changes in the rabbit larynx in response to low humidity challenge

BACKGROUND

Voice disorders are a worldwide problem impacting human health, particularly for occupational voice users. Avoidance of surface dehydration is commonly prescribed as a protective factor against the development of dysphonia. The available literature inconclusively supports this practice and a biological mechanism for how surface dehydration of the laryngeal tissue affects voice has not been described. In this study, we used an in vivo male New Zealand white rabbit model to elucidate biological changes based on gene expression within the vocal folds from surface dehydration. Surface dehydration was induced by exposure to low humidity air (18.6% + 4.3%) for 8 h. Exposure to moderate humidity (43.0% + 4.3%) served as the control condition. Ilumina-based RNA sequencing was performed and used for transcriptome analysis with validation by RT-qPCR.

RESULTS

There were 103 statistically significant differentially expressed genes identified through Cuffdiff with 61 genes meeting significance by both false discovery rate and fold change. Functional annotation enrichment and predicted protein interaction mapping showed enrichment of various loci, including cellular stress and inflammatory response, ciliary function, and keratinocyte development. Eight genes were selected for RT-qPCR validation. Matrix metalloproteinase 12 (MMP12) and macrophage cationic peptide 1 (MCP1) were significantly upregulated and an epithelial chloride channel protein (ECCP) was significantly downregulated after surface dehydration by RNA-Seq and RT-qPCR. Suprabasin (SPBN) and zinc activated cationic channel (ZACN) were marginally, but non-significantly down- and upregulated as evidenced by RT-qPCR, respectively.

CONCLUSIONS

The data together support the notion that surface dehydration induces physiological changes in the vocal folds and justifies targeted analysis to further explore the underlying biology of compensatory fluid/ion flux and inflammatory mediators in response to airway surface dehydration.

The differential prognostic impact of spread through air spaces in early-stage lung adenocarcinoma after lobectomy according to the pT descriptor

OBJECTIVES

We evaluated the differential prognostic impact of spread through air spaces (STAS) in early-stage lung adenocarcinoma after lobectomy according to the pT descriptor.

METHODS

The study population included 506 patients who underwent lobectomy with mediastinal lymph node dissection for pT1b, pT1c, and pT2a adenocarcinoma between 2011 and 2016. We divided the study population into 2 groups according to STAS status, ie, STAS (+) versus STAS (-), and stratified them according to the pT descriptor. A Cox proportional hazard model and inverse probability of treatment weight-adjusted Kaplan-Meier curves were used to evaluate the prognostic impact of STAS on recurrence-free survival (RFS) and its independency in each stratum.

RESULTS

Multivariable Cox proportional hazard regression analysis demonstrated that in pT1b and pT1c strata, STAS (+) patients had a 7.02-fold and 2.89-fold greater risk of recurrence than STAS (-) patients, respectively. However, in the pT2a stratum, STAS did not affect RFS. And the RFS of the STAS (+) pT1b/c strata was similar to that of the pT2a stratum. In the pT1b/c strata, inverse probability of treatment weighting-adjusted Kaplan-Meier curves also showed that RFS was significantly worse when STAS was present. Furthermore, the risks for locoregional and distant recurrence were both greater when STAS was present.

CONCLUSIONS

The presence of STAS increased the risk of recurrence independently from other poor prognostic factors in patients with pT1b/cN0M0 adenocarcinoma who underwent lobectomy, but not in pT2a patients. The presence of STAS in pT1b/cN0M0 adenocarcinoma was associated with a similar risk of recurrence to that of pT2aN0M0 adenocarcinoma.

The role of spread through air spaces (STAS) in lung adenocarcinoma prognosis and therapeutic decision making

Spread through air spaces (STAS) was included as a novel pattern of invasion in lung adenocarcinoma by the World Health Organization in 2015. Since then, multiple studies have investigated the association of STAS with clinicopathological and molecular features and its implication in the prognosis of early stage lung cancer patients undergoing different surgery types. The aim of this comprehensive review is to present current data on the role of STAS and its perspective in lung adenocarcinoma management.

Role of the mucins in pathogenesis of COPD: implications for therapy

Introduction: Evidence accumulated in the last decade has started to reveal the enormous complexity in the expression, interactions and functions of the large number of different mucins present in the different compartments of the human lower airways. This occurs both in normal subjects and in COPD patients in different clinical phases and stages of severity.Areas covered: We review the known physiological mechanisms that regulate mucin production in human lower airways of normal subjects, the changes in mucin synthesis/secretion in COPD patients and the clinical efficacy of drugs that modulate mucin synthesis/secretion.Expert opinion: It is evident that the old simplistic concept that mucus hypersecretion in COPD patients is associated with negative clinical outcomes is not valid and that the therapeutic potential of 'mucolytic drugs' is under-appreciated due to the complexity of the associated molecular network(s). Likewise, our current knowledge of the effects of the drugs already available on the market that target mucin synthesis/secretion/structure in the lower airways is extremely limited and often indirect and more well-controlled clinical trials are needed in this area.

Mucins and Pathogenic Mucin-Like Molecules Are Immunomodulators During Infection and Targets for Diagnostics and Vaccines

Mucins and mucin-like molecules are highly O-glycosylated proteins present on the cell surface of mammals and other organisms. These glycoproteins are highly diverse in the apoprotein and glycan cores and play a central role in many biological processes and diseases. Mucins are the most abundant macromolecules in mucus and are responsible for its biochemical and biophysical properties. Mucin-like molecules cover various protozoan parasites, fungi and viruses. In humans, modifications in mucin glycosylation are associated with tumors in epithelial tissue. These modifications allow the distinction between normal and abnormal cell conditions and represent important targets for vaccine development against some cancers. Mucins and mucin-like molecules derived from pathogens are potential diagnostic markers and targets for therapeutic agents. In this review, we summarize the distribution, structure, role as immunomodulators, and the correlation of human mucins with diseases and perform a comparative analysis of mucins with mucin-like molecules present in human pathogens. Furthermore, we review the methods to produce pathogenic and human mucins using chemical synthesis and expression systems. Finally, we present applications of mucin-like molecules in diagnosis and prevention of relevant human diseases.

Mucin 21 is a key molecule involved in the incohesive growth pattern in lung adenocarcinoma

Decreased cell adhesion has been reported as a significant negative prognostic factor of lung cancer. However, the molecular mechanisms responsible for the cell incohesiveness in lung cancer have not yet been elucidated in detail. We herein describe a rare histological variant of lung adenocarcinoma consisting almost entirely of individual cancer cells spreading in alveolar spaces in an incohesive pattern. A whole exome analysis of this case showed no genomic abnormalities in CDH1 or other genes encoding cell adhesion molecules. However, whole mRNA sequencing revealed that this case had an extremely high expression level of mucin 21 (MUC21), a mucin molecule that was previously shown to inhibit cell‐cell and cell‐matrix adhesion. The strong membranous expression of MUC21 was found on cancer cells using mAbs recognizing different O‐glycosylated forms of MUC21. An immunohistochemical analysis of an unselected series of lung adenocarcinoma confirmed that the strong membranous expression of MUC21 correlated with incohesiveness. Thus, MUC21 could be a promising biomarker with potential diagnostic and therapeutic applications for lung adenocarcinoma showing cell incohesiveness.