SOX2 Drives Bronchial Dysplasia in a Novel Organotypic Model of Early Human Squamous Lung Cancer

A human model to deconvolve genotype-phenotype causations in lung squamous cell carcinoma

Tractable, patient-relevant models are needed to investigate cancer progression and heterogeneity. Here, we report an alternative in vitro model of lung squamous cell carcinoma (LUSC) using primary human bronchial epithelial cells (hBECs) from three healthy donors. The co-operation of ubiquitous alterations (TP53 and CDKN2A loss) and components of commonly deregulated pathways including squamous differentiation (SOX2), PI3K signalling (PTEN) and the oxidative stress response (KEAP1) is investigated by generating hBECs harbouring cumulative alterations. Our analyses confirms that SOX2-overexpression initiates early preinvasive LUSC stages, and co-operation with the oxidative stress response and PI3K pathways to drive more aggressive phenotypes, with expansion of cells expressing LUSC biomarkers and invasive properties. This cooperation is consistent with the classical LUSC subtype. Importantly, we connect pathway dysregulation with gene expression changes associated with cell-intrinsic processes and immunomodulation. Our approach constitutes a powerful system to model LUSC and unravel genotype-phenotype causations of clinical relevance.

Defining precancer: a grand challenge for the cancer community

The term 'precancer' typically refers to an early stage of neoplastic development that is distinguishable from normal tissue owing to molecular and phenotypic alterations, resulting in abnormal cells that are at least partially self-sustaining and function outside of normal cellular cues that constrain cell proliferation and survival. Although such cells are often histologically distinct from both the corresponding normal and invasive cancer cells of the same tissue origin, defining precancer remains a challenge for both the research and clinical communities. Once sufficient molecular and phenotypic changes have occurred in the precancer, the tissue is identified as a 'cancer' by a histopathologist. While even diagnosing cancer can at times be challenging, the determination of invasive cancer is generally less ambiguous and suggests a high likelihood of and potential for metastatic disease. The 'hallmarks of cancer' set out the fundamental organizing principles of malignant transformation but exactly how many of these hallmarks and in what configuration they define precancer has not been clearly and consistently determined. In this Expert Recommendation, we provide a starting point for a conceptual framework for defining precancer, which is based on molecular, pathological, clinical and epidemiological criteria, with the goal of advancing our understanding of the initial changes that occur and opportunities to intervene at the earliest possible time point.

Chronic lung inflammation and CK14+ basal cell proliferation induce persistent alveolar-bronchiolization in SARS-CoV-2-infected hamsters

BACKGROUND

Post-acute sequalae of COVID-19 defines a wide range of ongoing symptoms and conditions long after SARS-CoV-2 infection including respiratory diseases. The histopathological changes in the lung and underlying mechanism remain elusive.

METHODS

We investigated lung histopathological and transcriptional changes in SARS-CoV-2-infected male hamsters at 7, 14, 42, 84 and 120dpi, and compared with A (H1N1)pdm09 infection.

FINDINGS

We demonstrated viral residue, inflammatory and fibrotic changes in lung after SARS-CoV-2 but not H1N1 infection. The most prominent histopathological lesion was multifocal alveolar-bronchiolization observed in every SARS-CoV-2 infected hamster (31/31), from 42dpi to 120dpi. Proliferating (Ki67+) CK14+ basal cells accumulated in alveoli adjacent to bronchioles at 7dpi, where they proliferated and differentiated into SCGB1A+ club cell or Tubulin+ ciliated cells forming alveolar-bronchiolization foci. Molecularly, Notch pathway significantly upregulated with intensive Notch3 and Hes1 protein expression in alveolar-bronchiolization foci at 42 and 120dpi, suggesting Notch signaling involving the persistence of alveolar-bronchiolization. This is further demonstrated by spatial transcriptomic analysis. Intriguingly, significant upregulation of some cell-growth promoting pathways and genes such as Tubb4b, Stxbp4, Grb14 and Mlf1 were spatially overlapping with bronchiolization lesion.

INTERPRETATION

Incomplete resolution of SARS-CoV-2 infection in lung with viral residue, chronic inflammatory and fibrotic damage and alveolar-bronchiolization impaired respiratory function. Aberrant activation of CK14+ basal cells during tissue regeneration led to persistent alveolar-bronchiolization due to sustained Notch signaling. This study advances our understanding of respiratory PASC, sheds light on disease management and highlights the necessity for monitoring disease progression in people with respiratory PASC.

FUNDING

Funding is listed in the Acknowledgements section.

Repeat treatment of organotypic airway cultures with ethyl methanesulfonate causes accumulation of somatic cell mutations without expansion of bronchial-carcinoma-specific cancer driver mutations

The human in vitro organotypic air-liquid-interface (ALI) airway tissue model is structurally and functionally similar to the human large airway epithelium and, as a result, is being used increasingly for studying the toxicity of inhaled substances. Our previous research demonstrated that DNA damage and mutagenesis can be detected in human airway tissue models under conditions used to assess general and respiratory toxicity endpoints. Expanding upon our previous proof-of-principle study, human airway epithelial tissue models were treated with 6.25-100 µg/mL ethyl methanesulfonate (EMS) for 28 days, followed by a 28-day recovery period. Mutagenesis was evaluated by Duplex Sequencing (DS), and clonal expansion of bronchial-cancer-specific cancer-driver mutations (CDMs) was investigated by CarcSeq to determine if both mutation-based endpoints can be assessed in the same system. Additionally, DNA damage and tissue-specific responses were analyzed during the treatment and following the recovery period. EMS exposure led to time-dependent increases in mutagenesis over the 28-day treatment period, without expansion of clones containing CDMs; the mutation frequencies remained elevated following the recovery. EMS also produced an increase in DNA damage measured by the CometChip and MultiFlow assays and the elevated levels of DNA damage were reduced (but not eliminated) following the recovery period. Cytotoxicity and most tissue-function changes induced by EMS treatment recovered to control levels, the exception being reduced proliferating cell frequency. Our results indicate that general, respiratory-tissue-specific and genotoxicity endpoints increased with repeat EMS dosing; expansion of CDM clones, however, was not detected using this repeat treatment protocol. DISCLAIMER: This article reflects the views of its authors and does not necessarily reflect those of the U.S. Food and Drug Administration. Any mention of commercial products is for clarification only and is not intended as approval, endorsement, or recommendation.

SOX2-associated signaling pathways regulate biological phenotypes of cancers

SOX2 is a transcription factor involved in multiple stages of embryonic development. In related reports, SOX2 was found to be abnormally expressed in tumor tissues and correlated with clinical features such as TNM staging, tumor grade, and prognosis in patients with various cancer types. In most cancer types, SOX2 is a tumor-promoting factor that regulates tumor progression and metastasis primarily by maintaining the stemness of cancer cells. In addition, SOX2 also regulates the proliferation, apoptosis, invasion, migration, ferroptosis and drug resistance of cancer cells. However, SOX2 acts as a tumor suppressor in some cases in certain cancer types, such as gastric and lung cancer. These key regulatory functions of SOX2 involve complex regulatory networks, including protein-protein and protein-nucleic acid interactions through signaling pathways and noncoding RNA interactions, modulating SOX2 expression may be a potential therapeutic strategy for clinical cancer patients. Therefore, we sorted out the phenotypes related to SOX2 in cancer, hoping to provide a basis for further clinical translation.

Interrogating the precancerous evolution of pathway dysfunction in lung squamous cell carcinoma using XTABLE

Lung squamous cell carcinoma (LUSC) is a type of lung cancer with a dismal prognosis that lacks adequate therapies and actionable targets. This disease is characterized by a sequence of low- and high-grade preinvasive stages with increasing probability of malignant progression. Increasing our knowledge about the biology of these premalignant lesions (PMLs) is necessary to design new methods of early detection and prevention, and to identify the molecular processes that are key for malignant progression. To facilitate this research, we have designed XTABLE (Exploring Transcriptomes of Bronchial Lesions), an open-source application that integrates the most extensive transcriptomic databases of PMLs published so far. With this tool, users can stratify samples using multiple parameters and interrogate PML biology in multiple manners, such as two- and multiple-group comparisons, interrogation of genes of interests, and transcriptional signatures. Using XTABLE, we have carried out a comparative study of the potential role of chromosomal instability scores as biomarkers of PML progression and mapped the onset of the most relevant LUSC pathways to the sequence of LUSC developmental stages. XTABLE will critically facilitate new research for the identification of early detection biomarkers and acquire a better understanding of the LUSC precancerous stages.

Cigarette smoke preferentially induces full length ACE2 expression in differentiated primary human airway cultures but does not alter the efficiency of cellular SARS-CoV-2 infection

Cigarette smoking has many serious negative health consequences. The relationship between smoking and SARS-CoV-2 infection is controversial, specifically whether smokers are at increased risk of infection. We investigated the impact of cigarette smoke on ACE2 isoform expression and SARS-CoV-2 infection in differentiated primary human bronchial epithelial cells at the air-liquid-interface (ALI). We assessed the expression of ACE2 in response to CSE and therapeutics reported to modulate ACE2. We exposed ALI cultures to cigarette smoke extract (CSE) and then infected them with SARS-CoV-2. We measured cellular infection using flow cytometry and whole-transwell immunofluorescence. We found that CSE increased expression of full-length ACE2 (flACE2) but did not alter the expression of a Type I-interferon sensitive truncated isoform (dACE2) that lacks the capacity to bind SARS-CoV-2. CSE did not have a significant impact on key mediators of the innate immune response. Importantly, we show that, despite the increase in flACE2, CSE did not alter airway cell infection after CSE exposure. We found that nicotine does not significantly alter flACE2 expression but that NRF2 agonists do lead to an increase in flACE2 expression. This increase was not associated with an increase in SARS-CoV-2 infection. Our results are consistent with the epidemiological data suggesting that current smokers do not have an excess of SARS-CoV-2 infection. but that those with chronic respiratory or cardiovascular disease are more vulnerable to severe COVID-19. They suggest that, in differentiated conducting airway cells, flACE2 expression levels may not limit airway SARS-CoV-2 infection.

Cell Cultures at the Air-Liquid Interface and Their Application in Cancer Research

Air-liquid interface (ALI) cell cultures are considered a valid tool for the replacement of animals in biomedical research. By mimicking crucial features of the human in vivo epithelial barriers (e.g., lung, intestine, and skin), ALI cell cultures enable proper structural architectures and differentiated functions of normal and diseased tissue barriers. Thereby, ALI models realistically resemble tissue conditions and provide in vivo-like responses. Since their implementation, they are routinely used in several applications, from toxicity testing to cancer research, receiving an appreciable level of acceptance (in some cases a regulatory acceptance) as attractive testing alternatives to animals. In this chapter, an overview of the ALI cell cultures will be presented together with their application in cancer cell culture, highlighting the potential advantages and disadvantages of the model.

LncRNA PCAT1 activates SOX2 and suppresses radioimmune responses via regulating cGAS/STING signalling in non-small cell lung cancer

Background

The expression of long non‐coding RNA (lncRNA) prostate cancer‐associated ncRNA transcripts 1 (PCAT1) is increased in non‐small cell lung cancer (NSCLC). It stimulates tumour growth and metastasis, but its role in the radioimmune responses remain unknown. We aimed to explore the impacts of PCAT1 on tumorigenesis and radioimmune responses and the underlying molecular mechanisms in NSCLC.

Methods

Comprehensive bioinformatics analysis was performed to identify immunosuppressive lncRNAs involved with tumour invasion in NSCLC. The expression levels of PCAT1 were analysed by in situ hybridisation in 55 paired NSCLC tissues and adjacent normal tissues. Both loss‐ and gain‐of‐function assays were performed to examine the effects of PCAT1 and SOX2 on NSCLC cell behaviours in vivo and in vitro. Bioinformatic analyses, chromatin isolation by RNA purification (ChIRP) and dual‐luciferase reporter assays were applied to validate the regulatory effects of PCAT1 on SOX2 expression. Chromatin immunoprecipitation, luciferase and rescue assays were utilised to identify the relationship between SOX2 and the cGAS/stimulator of interferon genes (STING) signalling.

Results

PCAT1 was immunosuppressive and related with NSCLC invasion. Increased PCAT1 was negatively correlated with immune cell infiltration in NSCLC. PCAT1 knockdown restrained proliferation, increased apoptosis, and repressed cell metastasis in vivo and in vitro. PCAT1 activated SOX2 that accelerated tumorigenesis and immunosuppression. SOX2 promoted tumour growth through inhibiting cytotoxic T‐cell immunity. Moreover, SOX2 restrained cGAS transcription and hampered downstream type I interferon (IFN)‐induced immune responses. Inhibition of PCAT1/SOX2 in collaboration with radiation further inhibited tumour growth, and initiated the cGAS/STING signalling pathway, which enhanced the immune responses of radiotherapy in NSCLC.

Conclusions

PCAT1/SOX2 axis promoted tumorigenesis and immunosuppression through inhibition of cGAS/STING signalling‐mediated T‐cell activation. Inhibition of PCAT1 and SOX2 synergised with radiotherapy to activate the immune response and could serve as potential therapeutic targets.

Lrig1 expression identifies airway basal cells with high proliferative capacity and restricts lung squamous cell carcinoma growth

Background

Lung squamous cell carcinoma (LUSC) accounts for a significant proportion of cancer deaths worldwide, and is preceded by the appearance of progressively disorganised pre-invasive lesions in the airway epithelium. Yet the biological mechanisms underlying progression of pre-invasive lesions into invasive LUSC are not fully understood. LRIG1 (leucine-rich repeats and immunoglobulin-like domains 1) is downregulated in pre-invasive airway lesions and invasive LUSC tumours and this correlates with decreased lung cancer patient survival.

Methods and results

Using an Lrig1 knock-in reporter mouse and human airway epithelial cells collected at bronchoscopy, we show that during homeostasis LRIG1 is heterogeneously expressed in the airway epithelium. In basal airway epithelial cells, the suspected cell of origin of LUSC, LRIG1 identifies a subpopulation of progenitor cells with higher in vitro proliferative and self-renewal potential in both the mouse and human. Using the N-nitroso-tris-chloroethylurea (NTCU)-induced murine model of LUSC, we find that Lrig1 loss-of-function leads to abnormally high cell proliferation during the earliest stages of pre-invasive disease and to the formation of significantly larger invasive tumours, suggesting accelerated disease progression.

Conclusion

Together, our findings identify LRIG1 as a marker of basal airway progenitor cells with high proliferative potential and as a regulator of pre-invasive lung cancer progression. This work highlights the clinical relevance of LRIG1 and the potential of the NTCU-induced LUSC model for functional assessment of candidate tumour suppressors and oncogenes.

LRIG1 is lost in development of squamous cell lung cancers. This study shows that LRIG1 marks basal airway progenitor cells with high proliferative potential and regulates progression of pre-invasive squamous cell lung cancer.https://bit.ly/3AbPtY3

Mapping lung squamous cell carcinoma pathogenesis through in vitro and in vivo models

Lung cancer is the main cause of cancer death worldwide, with lung squamous cell carcinoma (LUSC) being the second most frequent subtype. Preclinical LUSC models recapitulating human disease pathogenesis are key for the development of early intervention approaches and improved therapies. Here, we review advances and challenges in the generation of LUSC models, from 2D and 3D cultures, to murine models. We discuss how molecular profiling of premalignant lesions and invasive LUSC has contributed to the refinement of in vitro and in vivo models, and in turn, how these systems have increased our understanding of LUSC biology and therapeutic vulnerabilities.

Air-liquid interface cultures of the healthy and diseased human respiratory tract: promises, challenges and future directions

Air-liquid interface (ALI) culture models currently represent a valid instrument to recreate the typical aspects of the respiratory tract in vitro in both healthy and diseased state. They can help reducing the number of animal experiments, therefore, supporting the 3R principle. This review discusses ALI cultures and co-cultures derived from immortalized as well as primary cells, which are used to study the most common disorders of the respiratory tract, in terms of both pathophysiology and drug screening. The article displays ALI models used to simulate inflammatory lung diseases such as chronic obstructive pulmonary disease (COPD), asthma, cystic fibrosis, lung cancer, and viral infections. It also includes a focus on ALI cultures described in literature studying respiratory viruses such as SARS-CoV-2 causing the global Covid-19 pandemic at the time of writing this review. Additionally, commercially available models of ALI cultures are presented. Ultimately, the aim of this review is to provide a detailed overview of ALI models currently available and to critically discuss them in the context of the most prevalent diseases of the respiratory tract.

Progress towards non-small-cell lung cancer models that represent clinical evolutionary trajectories

Non-small-cell lung cancer (NSCLC) is the leading cause of cancer-related deaths worldwide. Although advances are being made towards earlier detection and the development of impactful targeted therapies and immunotherapies, the 5-year survival of patients with advanced disease is still below 20%. Effective cancer research relies on pre-clinical model systems that accurately reflect the evolutionary course of disease progression and mimic patient responses to therapy. Here, we review pre-clinical models, including genetically engineered mouse models and patient-derived materials, such as cell lines, primary cell cultures, explant cultures and xenografts, that are currently being used to interrogate NSCLC evolution from pre-invasive disease through locally invasive cancer to the metastatic colonization of distant organ sites.

SOX2 and squamous cancers

SOX2 is a pleiotropic nuclear transcription factor with major roles in stem cell biology and in development. Over the last 10 years SOX2 has also been implicated as a lineage-specific oncogene, notably in squamous carcinomas but also neurological tumours, particularly glioblastoma. Squamous carcinomas (SQCs) comprise a common group of malignancies for which there are no targeted therapeutic interventions. In this article we review the molecular epidemiological and laboratory evidence linking SOX2 with squamous carcinogenesis, explore in detail the multifaceted impact of SOX2 in SQC, describe areas of uncertainty and highlight areas for potential future research.

Mechanism of acquired resistance to nivolumab in lung squamous cell carcinoma: case report and review of the literature

Background: Immune checkpoint inhibitors targeting PD-1 and PD-L1 have noticeably improved the treatment landscape of advanced non-small-cell lung cancer, including lung squamous cell carcinoma (SCC). Although patients with immune checkpoint therapy can achieve long-term survival, acquired resistance has been recognized more frequently, while the underlying mechanisms are currently poorly understood. Materials and methods: Here, we report a patient with metastatic lung SCC treated with nivolumab as a first-line treatment for 28 months. Conclusion: The analysis of specimens prenivolumab and postnivolumab treatment suggests that genetic alterations in SOX2 and CDKN2A/CDKN2B and changes in the tumor microenvironment could be reasons for the acquired resistance to nivolumab observed in the lung SCC patient.

Novel prognostic molecular markers in lung cancer

Lung carcinoma, especially in its most commonly diagnosed non-small cell histological form, is a challenge to diagnose and treat worldwide, due to the prognosis in patients with this type of cancer being poor and mortality rates being high. However, a number of patients with this type of lung carcinoma exhibit a longer than average overall survival. The specific molecular background of non-small-cell lung cancer that favors longer survival has not yet been determined. The aim of the current study was to review articles published in the years 2017-2018 and create a list of the most important and strongest non-conventional factors that could be used in the future assessment of the prognosis of patients with adenocarcinoma and squamous cell carcinoma of the lung who cannot undergo current targeted therapy. Analysis identified multiple prognostic factors in non-small cell lung carcinoma, including tumor mutational burden, which was revealed to be independent of the tumor stage or grade as well as other factors, including age, sex or targeted therapy effects. The selected molecular factors exhibit the potential to be used in the treatment of patients with specific problematic lung cancer, and may contribute to setting recommendations for the diagnosis, prognosis and treatment of individual patients with lung cancer.

Integrative analysis of DNA methylation-driven genes for the prognosis of lung squamous cell carcinoma using MethylMix

Background: DNA methylation acts as a key component in epigenetic modifications of genomic function and functions as disease-specific prognostic biomarkers for lung squamous cell carcinoma (LUSC). This present study aimed to identify methylation-driven genes as prognostic biomarkers for LUSC using bioinformatics analysis. Materials and Methods: Differentially expressed RNAs were obtained using the edge R package from 502 LUSC tissues and 49 adjacent non-LUSC tissues. Differentially methylated genes were obtained using the limma R package from 504 LUSC tissues and 69 adjacent non-LUSC tissues. The methylation-driven genes were obtained using the MethylMix R package from 500 LUSC tissues with matched DNA methylation data and gene expression data and 69 non-LUSC tissues with DNA methylation data. Gene ontology and ConsensusPathDB pathway analysis were performed to analyze the functional enrichment of methylation-driven genes. Univariate and multivariate Cox regression analyses were performed to identify the independent effect of differentially methylated genes for predicting the prognosis of LUSC. Results: A total of 44 methylation-driven genes were obtained. Univariate and multivariate Cox regression analyses showed that twelve aberrant methylated genes (ATP6V0CP3, AGGF1P3, RP11-264L1.4, HIST1H4K, LINC01158, CH17-140K24.1, CTC-523E23.14, ADCYAP1, COX11P1, TRIM58, FOXD4L6, CBLN1) were entered into a Cox predictive model associated with overall survival in LUSC patients. Methylation and gene expression combined survival analysis showed that the survival rate of hypermethylation and low-expression of DQX1 and WDR61 were low. The expression of DQX1 had a significantly negatively correlated with the methylation site cg02034222. Conclusion: Methylation-driven genes DQX1 and WDR61 might be potential biomarkers for predicting the prognosis of LUSC.

Acquisition of Cancer Stem Cell-like Properties in Human Small Airway Epithelial Cells after a Long-term Exposure to Carbon Nanomaterials

Cancer stem cells (CSCs) are a key driver of tumor formation and metastasis, but how they are affected by nanomaterials is largely unknown. The present study investigated the effects of different carbon-based nanomaterials (CNMs) on neoplastic and CSC-like transformation of human small airway epithelial cells and determined the underlying mechanisms. Using a physiologically relevant exposure model (long-term/low-dose) with system validation using a human carcinogen, asbestos, we demonstrated that single-walled carbon nanotubes, multi-walled carbon nanotubes, ultrafine carbon black, and crocidolite asbestos induced particle-specific anchorage-independent colony formation, DNA-strand break, and p53 downregulation, indicating genotoxicity and carcinogenic potential of CNMs. The chronic CNM-exposed cells exhibited CSC-like properties as indicated by 3D spheroid formation, anoikis resistance, and CSC markers expression. Mechanistic studies revealed specific self-renewal and epithelial-mesenchymal transition (EMT)-related transcription factors that are involved in the cellular transformation process. Pathway analysis of gene signaling networks supports the role of SOX2 and SNAI1 signaling in CNM-mediated transformation. These findings support the potential carcinogenicity of high aspect ratio CNMs and identified molecular targets and signaling pathways that may contribute to the disease development.

Cancer-associated fibroblasts suppress SOX2-induced dysplasia in a lung squamous cancer coculture

Tumor−stroma interactions play a critical role in regulating tumorigenesis. However, how these interactions contribute to changes in tissue architecture and cell polarity observed during tumor development is unclear. Here we report a 3D coculture system that recapitulates key phenotypic changes during the progression of lung squamous carcinoma (LUSC) as well as the dynamic interactions between LUSC cells and components of the tumor microenvironment (TME). Our data suggest that two major components of TME, including the extracellular matrix and cancer-associated fibroblasts, could override cell intrinsic oncogenic changes in determining the disease phenotype in the context of LUSC. These findings may have broad implications for LUSC biology as well as the design of future therapies.

Tumorigenesis depends on intricate interactions between genetically altered tumor cells and their surrounding microenvironment. While oncogenic drivers in lung squamous carcinoma (LUSC) have been described, the role of stroma in modulating tissue architecture, particularly cell polarity, remains unclear. Here, we report the establishment of a 3D coculture system of LUSC epithelial cells with cancer-associated fibroblasts (CAFs) and extracellular matrix that together capture key components of the tumor microenvironment (TME). Single LUSC epithelial cells develop into acinar-like structures with 0.02% efficiency, and addition of CAFs provides proper tumor−stromal interactions within an appropriate 3D architectural context. Using this model, we recapitulate key pathological changes during tumorigenesis, from hyperplasia to dysplasia and eventually invasion, in malignant LUSC spheroids that undergo phenotypic switching in response to cell intrinsic and extrinsic changes. Overexpression of SOX2 is sufficient to mediate the transition from hyperplasia to dysplasia in LUSC spheroids, while the presence of CAFs makes them invasive. Unexpectedly, CAFs suppress the activity of high SOX2 levels, restore hyperplasia, and enhance the formation of acinar-like structures. Taken together, these observations suggest that stromal factors can override cell intrinsic oncogenic changes in determining the disease phenotype, thus providing fundamental evidence for the existence of dynamic reciprocity between the nucleus and the TME of LUSC.

Diagnostic Value of Multi-Slice Spiral Computed Tomography for Bronchial Dysplasia in Premature Infants

Background

The aim of this study was to investigate the diagnostic value of multi-slice spiral computed tomography (MSCT) for bronchial dysplasia in premature infants.

Material/Methods

A retrospective analysis of 248 premature infants who were highly suspected to have bronchial dysplasia and were admitted to our hospital from 2015 onwards was conducted. We observed bronchus morphologies, sizes, and tissue characteristics using fiberoptic bronchoscopy (FB) as the criterion standard for diagnosis. We calculated the sensitivity, specificity, and diagnostic compliance of MSCT in the diagnosis of bronchial dysplasia.

Results

Thoracic computed tomography mainly revealed capsular bubbles. The translucency of the 2 lungs was reduced, and extensive and local ground-glass changes were observed. Imaging findings mostly included strip or honeycomb-like shadows. Pleural thickening and pleural effusion were rare. MSCT was able to establish a diagnosis in 92 cases (37.10%) of bronchopulmonary cysts, 69 cases (27.82%) of congenital pulmonary emphysema, 31 cases (12.50%) of bronchial atresia, 1 case (0.40%) of congenital cystadenoma malformation, and 3 cases (1.21%) of giant tracheal bronchitis. Another 52 children (20.97%) were found to have conventional pulmonary inflammation. The sensitivity of MSCT in the diagnosis of bronchial dysplasia was 88.21%, the specificity was 75.00%, and the diagnostic compliance was 86.29%. There was a significant difference between the MSCT and FB findings in the diagnosis of bronchial hypoplasia (P<0.001).

Conclusions

MSCT has great utility in the diagnosis of bronchial dysplasia in premature infants and may become an excellent method for diagnosing bronchial dysplasia in the future.

Successful Establishment of Primary Type II Alveolar Epithelium with 3D Organotypic Coculture

Alveolar type II (AT2) epithelial cells are uniquely specialized to produce surfactant in the lung and act as progenitor cells in the process of repair after lung injury. AT2 cell injury has been implicated in several lung diseases, including idiopathic pulmonary fibrosis and bronchopulmonary dysplasia. The inability to maintain primary AT2 cells in culture has been a significant barrier in the investigation of pulmonary biology. We have addressed this knowledge gap by developing a three-dimensional (3D) organotypic coculture using primary human fetal AT2 cells and pulmonary fibroblasts. Grown on top of matrix-embedded fibroblasts, the primary human AT2 cells establish a monolayer and have direct contact with the underlying pulmonary fibroblasts. Unlike conventional two-dimensional (2D) culture, the structural and functional phenotype of the AT2 cells in our 3D organotypic culture was preserved over 7 days of culture, as evidenced by the presence of lamellar bodies and by production of surfactant proteins B and C. Importantly, the AT2 cells in 3D cocultures maintained the ability to replicate, with approximately 60% of AT2 cells staining positive for the proliferation marker Ki67, whereas no such proliferation is evident in 2D cultures of the same primary AT2 cells. This organotypic culture system enables interrogation of AT2 epithelial biology by providing a reductionist in vitro model in which to investigate the response of AT2 epithelial cells and AT2 cell-fibroblast interactions during lung injury and repair.

Knockdown of long non-coding RNA NEAT1 inhibits glioma cell migration and invasion via modulation of SOX2 targeted by miR-132

BACKGROUND

A better understanding of the molecular mechanism involving lncRNA-miRNA-mRNA network underlying glioma genesis is beneficial to the treatment of glioma. This study was designed to investigate the role of lncRNA NEAT1, miR-132 and SOX2 interaction in glioma.

METHODS

Microarray analysis was conducted to identify the differentially expressed lncRNAs in glioma tissues. The expression levels of NEAT1, miR-132 and SOX2 were determined by qRT-PCR and western blot. Proliferation of glioma cells was detected by MTT assay, while migration and invasion were determined by transwell assay. The target relationships were predicted by miRcode algorithm, and confirmed by dual luciferase reporter gene assay.

RESULTS

NEAT1 was up-regulated in glioma. Knockdown of NEAT1 inhibited glioma cells' viability, migration and invasion. MiR-132 was down-regulated while SOX2 was up-regulated in glioma cells. NEAT1 negatively regulated the expression of miR-132 in glioma while miR-132 targeted SOX2 to down-regulate its expression.

CONCLUSION

NEAT1 promoted glioma development by promoting SOX2 expression through suppressing miR-132.

Airway Basal Cell Heterogeneity and Lung Squamous Cell Carcinoma

Basal cells are stem/progenitor cells that maintain airway homeostasis, enact repair following epithelial injury, and are a candidate cell-of-origin for lung squamous cell carcinoma. Heterogeneity of basal cells is recognized in terms of gene expression and differentiation capacity. In this Issue, Pagano and colleagues isolate a subset of immortalized basal cells that are characterized by high motility, suggesting that they might also be heterogeneous in their biophysical properties. Motility-selected cells displayed an increased ability to colonize the lung in vivo The possible implications of these findings are discussed in terms of basal cell heterogeneity, epithelial cell migration, and modeling of metastasis that occurs early in cancer evolution. Cancer Prev Res; 10(9); 491-3. ©2017 AACRSee related article by Pagano et al., p. 514.

FGFR2 is required for airway basal cell self-renewal and terminal differentiation

Airway stem cells slowly self-renew and produce differentiated progeny to maintain homeostasis throughout the lifespan of an individual. Mutations in the molecular regulators of these processes may drive cancer or degenerative disease, but are also potential therapeutic targets. Conditionally deleting one copy of FGF receptor 2 (FGFR2) in adult mouse airway basal cells results in self-renewal and differentiation phenotypes. We show that FGFR2 signalling correlates with maintenance of expression of a key transcription factor for basal cell self-renewal and differentiation: SOX2. This heterozygous phenotype illustrates that subtle changes in receptor tyrosine kinase signalling can have significant effects, perhaps providing an explanation for the numerous changes seen in cancer.

Summary: During adult airway epithelial homeostasis in mice, FGFR2 signalling is required for self-renewing divisions of basal stem cells and to maintain expression of the key transcription factor SOX2.