Ontogeny and Biology of Human Small Airway Epithelial Club Cells.

RATIONALE: Little is known about human club cells, dome-shaped cells with dense cytoplasmic granules and microvilli that represent the major secretory cells of the human small airways (at least sixth-generation bronchi). OBJECTIVES: To define the ontogeny and biology of the human small airway epithelium club cell. METHODS: The small airway epithelium was sampled from the normal human lung by bronchoscopy and brushing. Single-cell transcriptome analysis and air-liquid interface culture were used to assess club cell ontogeny and biology. MEASUREMENTS AND MAIN RESULTS: We identified the club cell population by unbiased clustering using single-cell transcriptome sequencing. Principal component gradient analysis uncovered an ontologic link between KRT5 (keratin 5)+ basal cells and SCGB1A1 (secretoglobin family 1A member 1)+ club cells, a hypothesis verified by demonstrating in vitro that a pure population of human KRT5+ SCGB1A1- small airway epithelial basal cells differentiate into SCGB1A1+KRT5- club cells on air-liquid interface culture. Using SCGB1A1 as the marker of club cells, the single-cell analysis identified novel roles for these cells in host defense, xenobiotic metabolism, antiprotease, physical barrier function, monogenic lung disorders, and receptors for human viruses. CONCLUSIONS: These observations provide novel insights into the molecular phenotype and biologic functions of the human club cell population and identify basal cells as the human progenitor cells for club cells.

Altered lung biology of healthy never smokers following acute inhalation of E-cigarettes.

BACKGROUND: Little is known about health risks associated with electronic cigarette (EC) use although EC are rising in popularity and have been advocated as a means to quit smoking cigarettes. METHODS: Ten never-smokers, without exposure history to tobacco products or EC, were assessed at baseline with questionnaire, chest X-ray, lung function, plasma levels of endothelial microparticles (EMP), and bronchoscopy to obtain small airway epithelium (SAE) and alveolar macrophages (AM). One week later, subjects inhaled 10 puffs of "Blu" brand EC, waited 30 min, then another 10 puff; n = 7 were randomized to EC with nicotine and n = 3 to EC without nicotine to assess biological responses in healthy, naive individuals. RESULTS: Two hr. post-EC exposure, subjects were again assessed as at baseline. No significant changes in clinical parameters were observed. Biological changes were observed compared to baseline, including altered transcriptomes of SAE and AM for all subjects and elevated plasma EMP levels following inhalation of EC with nicotine. CONCLUSIONS: This study provides in vivo human data demonstrating that acute inhalation of EC aerosols dysregulates normal human lung homeostasis in a limited cohort of healthy naïve individuals. These observations have implications to new EC users, nonsmokers exposed to secondhand EC aerosols and cigarette smokers using EC to quit smoking. TRIAL REGISTRATION: ClinicalTrials.gov NCT01776398 (registered 10/12/12), NCT02188511 (registered 7/2/14).

POU2AF1 Functions in the Human Airway Epithelium To Regulate Expression of Host Defense Genes.

In the process of seeking novel lung host defense regulators by analyzing genome-wide RNA sequence data from normal human airway epithelium, we detected expression of POU domain class 2-associating factor 1 (POU2AF1), a known transcription cofactor previously thought to be expressed only in lymphocytes. Lymphocyte contamination of human airway epithelial samples obtained by bronchoscopy and brushing was excluded by immunohistochemistry staining, the observation of upregulation of POU2AF1 in purified airway basal stem/progenitor cells undergoing differentiation, and analysis of differentiating single basal cell clones. Lentivirus-mediated upregulation of POU2AF1 in airway basal cells induced upregulation of host defense genes, including MX1, IFIT3, IFITM, and known POU2AF1 downstream genes HLA-DRA, ID2, ID3, IL6, and BCL6. Interestingly, expression of these genes paralleled changes of POU2AF1 expression during airway epithelium differentiation in vitro, suggesting POU2AF1 helps to maintain a host defense tone even in pathogen-free condition. Cigarette smoke, a known risk factor for airway infection, suppressed POU2AF1 expression both in vivo in humans and in vitro in human airway epithelial cultures, accompanied by deregulation of POU2AF1 downstream genes. Finally, enhancing POU2AF1 expression in human airway epithelium attenuated the suppression of host defense genes by smoking. Together, these findings suggest a novel function of POU2AF1 as a potential regulator of host defense genes in the human airway epithelium.

Smoking-Dependent Distal-to-Proximal Repatterning of the Adult Human Small Airway Epithelium.

RATIONALE: Small airways are the primary site of pathologic changes in chronic obstructive pulmonary disease (COPD), the major smoking-induced lung disorder. OBJECTIVES: On the basis of the concept of proximal-distal patterning that determines regional specialization of the airway epithelium during lung development, we hypothesized that a similar program operates in the adult human lung being altered by smoking, leading to decreased regional identity of the small airway epithelium (SAE). METHODS: The proximal and distal airway signatures were identified by comparing the transcriptomes of large and small airway epithelium samples obtained by bronchoscopy from healthy nonsmokers. The expression of these signatures was evaluated in the SAE of healthy smokers and smokers with COPD compared with that of healthy nonsmokers. The capacity of airway basal stem cells (BCs) to maintain region-associated phenotypes was evaluated using the air-liquid interface model. MEASUREMENTS AND MAIN RESULTS: The distal and proximal airway signatures, containing 134 and 233 genes, respectively, were identified. These signatures included known developmental regulators of airway patterning, as well as novel regulators such as epidermal growth factor receptor, which was associated with the proximal airway phenotype. In the SAE of smokers with COPD, there was a dramatic smoking-dependent loss of the regional transcriptome identity with concomitant proximalization. This repatterning phenotype was reproduced by stimulating SAE BCs with epidermal growth factor, which was up-regulated in the SAE of smokers, during differentiation of SAE BCs in vitro. CONCLUSIONS: Smoking-induced global distal-to-proximal reprogramming of the SAE represents a novel pathologic feature of COPD and is mediated by exaggerated epidermal growth factor/epidermal growth factor receptor signaling in SAE BCs.

Pulmonary Abnormalities in Young, Light-Use Waterpipe (Hookah) Smokers.

RATIONALE: Waterpipes, also called hookahs, are currently used by millions of people worldwide. Despite the increasing use of waterpipe smoking, there is limited data on the health effects of waterpipe smoking and there are no federal regulations regarding its use. OBJECTIVES: To assess the effects of waterpipe smoking on the human lung using clinical and biological parameters in young, light-use waterpipe smokers. METHODS: We assessed young, light-use, waterpipe-only smokers in comparison with lifelong nonsmokers using clinical parameters of cough and sputum scores, lung function, and chest high-resolution computed tomography as well as biological parameters of lung epithelial lining fluid metabolome, small airway epithelial (SAE) cell differential and transcriptome, alveolar macrophage transcriptome, and plasma apoptotic endothelial cell microparticles. MEASUREMENTS AND MAIN RESULTS: Compared with nonsmokers, waterpipe smokers had more cough and sputum as well as a lower lung diffusing capacity, abnormal epithelial lining fluid metabolome profile, increased proportions of SAE secretory and intermediate cells, reduced proportions of SAE ciliated and basal cells, markedly abnormal SAE and alveolar macrophage transcriptomes, and elevated levels of apoptotic endothelial cell microparticles. CONCLUSIONS: Young, light-use, waterpipe-only smokers have a variety of abnormalities in multiple lung-related biological and clinical parameters, suggesting that even limited waterpipe use has broad consequences on human lung biology and health. We suggest that large epidemiological studies should be initiated to investigate the harmful effects of waterpipe smoking.

Persistence of circulating endothelial microparticles in COPD despite smoking cessation.

INTRODUCTION: Increasing evidence links COPD pathogenesis with pulmonary capillary apoptosis. We previously demonstrated that plasma levels of circulating microparticles released from endothelial cells (EMPs) due to apoptosis are elevated in smokers with normal spirometry but low diffusion capacity, that is, with early evidence of lung destruction. We hypothesised that pulmonary capillary apoptosis persists with the development of COPD and assessed its reversibility in healthy smokers and COPD smokers following smoking cessation. METHODS: Pulmonary function and high-resolution CT (HRCT) were assessed in 28 non-smokers, 61 healthy smokers and 49 COPD smokers; 17 healthy smokers and 18 COPD smokers quit smoking for 12 months following the baseline visit. Total EMP (CD42b-CD31+), pulmonary capillary EMP (CD42b-CD31+ACE+) and apoptotic EMP (CD42b-CD62E+/CD42b-CD31+) levels were quantified by flow cytometry. RESULTS: Compared with non-smokers, healthy smokers and COPD smokers had elevated levels of circulating EMPs due to active pulmonary capillary endothelial apoptosis. Levels remained elevated over 12 months in healthy smokers and COPD smokers who continued smoking, but returned to non-smoker levels in healthy smokers who quit. In contrast, levels remained significantly abnormal in COPD smokers who quit. CONCLUSIONS: Pulmonary capillary apoptosis is reversible in healthy smokers who quit, but continues to play a role in COPD pathogenesis in smokers who progressed to airflow obstruction despite smoking cessation. TRIAL REGISTRATION NUMBER: NCT00974064; NCT01776398.

Copy number variations in the genome of the Qatari population.

BACKGROUND: The populations of the Arabian Peninsula remain the least represented in public genetic databases, both in terms of single nucleotide variants and of larger genomic mutations. We present the first high-resolution copy number variation (CNV) map for a Gulf Arab population, using a hybrid approach that integrates array genotyping intensity data and next-generation sequencing reads to call CNVs in the Qatari population. METHODS: CNVs were detected in 97 unrelated Qatari individuals by running two calling algorithms on each of two primary datasets: high-resolution genotyping (Illumina Omni 2.5M) and high depth whole-genome sequencing (Illumina PE 100bp). The four call-sets were integrated to identify high confidence CNV regions, which were subsequently annotated for putative functional effect and compared to public databases of CNVs in other populations. The availability of genome sequence was leveraged to identify tagging SNPs in high LD with common deletions in this population, enabling their imputation from genotyping experiments in the future. RESULTS: Genotyping intensities and genome sequencing data from 97 Qataris were analyzed with four different algorithms and integrated to discover 16,660 high confidence CNV regions (CNVRs) in the total population, affecting ~28 Mb in the median Qatari genome. Up to 40% of all CNVs affected genes, including novel CNVs affecting Mendelian disease genes, segregating at different frequencies in the 3 major Qatari subpopulations, including those with Bedouin, Persian/South Asian, and African ancestry. Consistent with high consanguinity levels in the Bedouin subpopulation, we found an increased burden for homozygous deletions in this group. In comparison to known CNVs in the comprehensive Database of Genomic Variants, we found that 5% of all CNVRs in Qataris were completely novel, with an enrichment of CNVs affecting several known chromosomal disorder loci and genes known to regulate sugar metabolism and type 2 diabetes in the Qatari cohort. Finally, we leveraged the availability of genome sequence to find suitable tagging SNPs for common deletions in this population. CONCLUSION: We combine four independently generated datasets from 97 individuals to study CNVs for the first time at high-resolution in a Gulf Arab population.

Cigarette smoking induces small airway epithelial epigenetic changes with corresponding modulation of gene expression.

The small airway epithelium (SAE), the first site of smoking-induced lung pathology, exhibits genome-wide changes in gene expression in response to cigarette smoking. Based on the increasing evidence that the epigenome can respond to external stimuli in a rapid manner, we assessed the SAE of smokers for genome-wide DNA methylation changes compared with nonsmokers, and whether changes in SAE DNA methylation were linked to the transcriptional output of these cells. Using genome-wide methylation analysis of SAE DNA of nonsmokers and smokers, the data identified 204 unique genes differentially methylated in SAE DNA of smokers compared with nonsmokers, with 67% of the regions with differential methylation occurring within 2 kb of the transcriptional start site. Among the genes with differential methylation were those related to metabolism, transcription, signal transduction and transport. For the differentially methylated genes, 35 exhibited a correlation with gene expression, 54% with an inverse correlation of DNA methylation with gene expression and 46% a direct correlation. These observations provide evidence that cigarette smoking alters the DNA methylation patterning of the SAE and that, for some genes, these changes are associated with the smoking-related changes in gene expression.

Role of SLMAP genetic variants in susceptibility of diabetes and diabetic retinopathy in Qatari population.

BACKGROUND: Overexpression of SLMAP gene has been associated with diabetes and endothelial dysfunction of macro- and micro-blood vessels. In this study our primary objective is to explore the role of SLMAP gene polymorphisms in the susceptibility of type 2 diabetes (T2DM) with or without diabetic retinopathy (DR) in the Qatari population. METHODS: A total of 342 Qatari subjects (non-diabetic controls and T2DM patients with or without DR) were genotyped for SLMAP gene polymorphisms (rs17058639 C > T; rs1043045 C > T and rs1057719 A > G) using Taqman SNP genotyping assay. RESULTS: SLMAP rs17058639 C > T polymorphism was associated with the presence of DR among Qataris with T2DM. One-way ANOVA and multiple logistic regression analysis showed SLMAP SNP rs17058639 C > T as an independent risk factor for DR development. SLMAP rs17058639 C > T polymorphism also had a predictive role for the severity of DR. Haplotype Crs17058639Trs1043045Ars1057719 was associated with the increased risk for DR among Qataris with T2DM. CONCLUSIONS: The data suggests the potential role of SLMAP SNPs as a risk factor for the susceptibility of DR among T2DM patients in the Qatari population.

Smoking accelerates aging of the small airway epithelium.

BACKGROUND: Aging involves multiple biologically complex processes characterized by a decline in cellular homeostasis over time leading to a loss and impairment of physiological integrity and function. Specific cellular hallmarks of aging include abnormal gene expression patterns, shortened telomeres and associated biological dysfunction. Like all organs, the lung demonstrates both physiological and structural changes with age that result in a progressive decrease in lung function in healthy individuals. Cigarette smoking accelerates lung function decline over time, suggesting smoking accelerates aging of the lung. Based on this data, we hypothesized that cigarette smoking accelerates the aging of the small airway epithelium, the cells that take the initial brunt of inhaled toxins from the cigarette smoke and one of the primary sites of pathology associated with cigarette smoking. METHODS: Using the sensitive molecular parameters of aging-related gene expression and telomere length, the aging process of the small airway epithelium was assessed in age matched healthy nonsmokers and healthy smokers with no physical manifestation of lung disease or abnormalities in lung function. RESULTS: Analysis of a 73 gene aging signature demonstrated that smoking significantly dysregulates 18 aging-related genes in the small airway epithelium. In an independent cohort of male subjects, smoking significantly reduced telomere length in the small airway epithelium of smokers by 14% compared to nonsmokers. CONCLUSION: These data provide biologic evidence that smoking accelerates aging of the small airway epithelium.

Generation of a human airway epithelium derived basal cell line with multipotent differentiation capacity.

BACKGROUND: As the multipotent progenitor population of the airway epithelium, human airway basal cells (BC) replenish the specialized differentiated cell populations of the mucociliated airway epithelium during physiological turnover and repair. Cultured primary BC divide a limited number of times before entering a state of replicative senescence, preventing the establishment of long-term replicating cultures of airway BC that maintain their original phenotype. METHODS: To generate an immortalized human airway BC cell line, primary human airway BC obtained by brushing the airway epithelium of healthy nonsmokers were infected with a retrovirus expressing human telomerase (hTERT). The resulting immortalized cell line was then characterized under non-differentiating and differentiating air-liquid interface (ALI) culture conditions using ELISA, TaqMan quantitative PCR, Western analysis, and immunofluorescent and immunohistochemical staining analysis for cell type specific markers. In addition, the ability of the cell line to respond to environmental stimuli under differentiating ALI culture was assessed. RESULTS: We successfully generated an immortalized human airway BC cell line termed BCi-NS1 via expression of hTERT. A single cell derived clone from the parental BCi-NS1 cells, BCi-NS1.1, retains characteristics of the original primary cells for over 40 passages and demonstrates a multipotent differentiation capacity into secretory (MUC5AC, MUC5B), goblet (TFF3), Clara (CC10) and ciliated (DNAI1, FOXJ1) cells on ALI culture. The cells can respond to external stimuli such as IL-13, resulting in alteration of the normal differentiation process. CONCLUSION: Development of immortalized human airway BC that retain multipotent differentiation capacity over long-term culture should be useful in understanding the biology of BC, the response of BC to environmental stress, and as a target for assessment of pharmacologic agents.

Nuclear factor kappa B pathway associated biomarkers in AIDS defining malignancies.

The nuclear factor kappa B (NFκB) pathway is essential for many human cancers. Therapeutics such as bortezomib (Velcade™) that interfere with NFκB signaling are of great clinical interest. NFκB signaling, however, is multifaceted and variable among tissues, developmental and disease entities. Hence, targeted biomarkers of NFκB pathways are of prime importance for clinical research. We developed a novel real-time qPCR-based NFκB array. Only mechanistically validated NFκB targets were included. We then used random-forest classification to define individual genes and gene combinations within the NFκB pathways that define viral lymphoma subclasses as well as Kaposi sarcoma (KS). Few NFκB targets emerged that were universally present in all tumor types tested, underscoring the need for additional tumor-type specific biomarker discovery. (i) We uncovered tissue of origin-specific tumor markers, specifically CD69, CSF-1 and complement factor B (C1QBP) for primary effusion lymphoma (PEL); IL1-beta, cyclinD3 and CD48 for KS. We found that IL12, jun-B, msx-1 and thrombospondin 2 were associated with EBV co-infection in PEL. (ii) We defined the NFκB signature of Epstein-Barr virus (EBV) positive AIDS-associated Burkitt lymphoma (BL). This signature identified CCR5 as the key marker. (iii) This signature differed from EBV negative BL consistent with the idea that EBV not only activates NFκB activity but that this virus also reprograms NFκB signaling toward different targets.

Distinct p53, p53:LANA, and LANA complexes in Kaposi's Sarcoma--associated Herpesvirus Lymphomas.

The role of p53 in primary effusion lymphoma (PEL) is complicated. The latency-associated nuclear antigen (LANA) of Kaposi's sarcoma-associated herpesvirus (KSHV) binds p53. Despite this interaction, we had found that p53 was functional in PEL, i.e., able to induce apoptosis in response to DNA damage (C. E. Petre, S. H. Sin, and D. P. Dittmer, J. Virol. 81:1912-1922, 2007), and that hdm2 was overexpressed. To further elucidate the relationship between LANA, p53, and hdm2, we purified LANA complexes from PEL by column chromatography. This confirmed that LANA bound p53. However, the LANA:p53 complexes were a minority compared to hdm2:p53 and p53:p53 complexes. The half-life of p53 was not extended, which is in contrast to the half-life of simian virus 40 T antigen-transformed cells. p53:p53, LANA:p53, and LANA:LANA complexes coexisted in PEL, and each protein was able to bind to its cognate DNA element. These data suggest that under normal conditions, p53 is inactive in PEL, thus allowing for exponential growth, but that this inactivation is driven by the relative stoichiometries of LANA, hdm2, and p53. If p53 is activated by DNA damage or nutlin-3a, the complex falls apart easily, and p53 exercises its role as guardian of the genome.

Model cell culture system for defining the molecular and biochemical events mediating terminal differentiation of human melanoma cells.

Cancer cells are commonly less differentiated than their normal progenitors; a phenotype that correlates with loss of specialized functions and an increased capability to self-renew. Melanoma is an ideal model to analyze cancer progression and differentiation since a well-characterized process of step-wise tumor progression has been defined. Our lab previously described a combinatorial in vitro treatment protocol to induce terminal differentiation of human melanoma cells using a low dose of the PKC activator Mezerein (Mez) combined with interferon-beta (IFN-beta), which also activates IFN-stimulated gene expression in addition to the re-differentiation program. In principle, using an alternate way to induce terminal differentiation not including IFN-beta would be more compatible with gene expression profiling. A higher concentration of Mez alone induced terminal differentiation of HO-1 human melanoma cells as measured by morphological, growth and biochemical assays. Pre-treatment with the PKC inhibitor GF109203x blocked changes associated with differentiation and inhibited the ability of Mez to force irreversible/terminal differentiation. By combining this efficient method of inducing terminal differentiation with microarray analyses we now identify potential regulators of this process and demonstrate utility of this novel in vitro model in which to study the molecular determinants and mechanisms of human melanoma differentiation.

Mandatory role of HMGA1 in human airway epithelial normal differentiation and post-injury regeneration.

Due to high levels of expression in aggressive tumors, high mobility group AT-hook 1 (HMGA1) has recently attracted attention as a potential anti-tumor target. However, HMGA1 is also expressed in normal somatic progenitor cells, raising the question: how might systemic anti-HMGA1 therapies affect the structure and function of normal tissue differentiation? In the present study, RNA sequencing data demonstrated HMGA1 is highly expressed in human airway basal stem/progenitor cells (BC), but decreases with BC differentiation in air-liquid interface cultures (ALI). BC collected from nonsmokers, healthy smokers, and smokers with chronic obstructive pulmonary disease (COPD) displayed a range of HMGA1 expression levels. Low initial expression levels of HMGA1 in BC were associated with decreased ability to maintain a differentiated ALI epithelium. HMGA1 down-regulation in BC diminished BC proliferation, suppressed gene expression related to normal proliferation and differentiation, decreased airway epithelial resistance, suppressed junctional and cell polarity gene expression, and delayed wound closure of airway epithelium following injury. Furthermore, silencing of HMGA1 in airway BC in ALI increased the expression of genes associated with airway remodeling in COPD including squamous, epithelial-mesenchymal transition (EMT), and inflammatory genes. Together, the data suggests HMGA1 plays a central role in normal airway differentiation, and thus caution should be used to monitor airway epithelial structure and function in the context of systemic HMGA1-targeted therapies.

Exome sequencing-based identification of novel type 2 diabetes risk allele loci in the Qatari population.

BACKGROUND: Type 2 diabetes (T2D) susceptibility is influenced by genetic and lifestyle factors. To date, the majority of genetic studies of T2D have been in populations of European and Asian descent. The focus of this study is on genetic variations underlying T2D in Qataris, a population with one of the highest incidences of T2D worldwide. RESULTS: Illumina HiSeq exome sequencing was performed on 864 Qatari subjects (574 T2D cases, 290 controls). Sequence kernel association test (SKAT) gene-based analysis identified an association for low frequency potentially deleterious variants in 6 genes. However, these findings were not replicated by SKAT analysis in an independent cohort of 12,699 exomes, primarly due to the absence of low frequency potentially deleterious variants in 5 of the 6 genes. Interestingly one of the genes identified, catenin beta 1 (CTNNB1, ß-catenin), is the key effector of the Wnt pathway and interacts with the nuclear receptor transcription factor 7-like 2 (TCF7L2), variants which are the most strongly associated with risk of developing T2D worldwide. Single variant analysis did not identify any associated variants, suggesting the SKAT association signal was not driven by individual variants. None of the 6 associated genes were among 634 previously described T2D genes. CONCLUSIONS: The observation that genes not previously linked to T2D in prior studies of European and Asian populations are associated with T2D in Qatar provides new insights into the complexity of T2D pathogenesis and emphasizes the importance of understudied populations when assessing genetic variation in the pathogenesis of common disorders.

mda-7/IL-24, novel anticancer cytokine: focus on bystander antitumor, radiosensitization and antiangiogenic properties and overview of the phase I clinical experience (Review).

Subtraction hybridization applied to a 'differentiation therapy' model of cancer employing human melanoma cells resulted in the cloning of melanoma differentiation associated gene-7/interleukin-24 (mda-7/IL-24). Initial studies confirm an inverse correlation between mda-7 expression and melanoma development and progression. Forced expression of mda-7 by means of a plasmid or via a replication incompetent adenovirus (Ad.mda-7) promotes growth suppression and induces apoptosis in a broad array of human cancers. In contrast, mda-7 does not induce growth suppressive or toxic effects in normal cells. Based on structure (containing an IL-10 signature motif), secretion by cells (including subsets of T-cells) and location on chromosome 1q (in an area containing IL-10-family genes), mda-7 has now been renamed mda-7/IL-24. Studies by several laboratories have uncovered many of mda-7/IL-24's unique properties, including cancer-specific apoptosis-induction, cell cycle regulation, an ability to inhibit angiogenesis, potent 'bystander antitumor activity' and a capacity to enhance the sensitivity of tumor cells to radiation, chemotherapy and monoclonal antibody therapy. Moreover, based on its profound cancer tropism, substantiated by in vivo human xenograft studies in nude mice, mda-7/IL-24 (administered as Ad.mda-7) was evaluated in a phase I clinical trial in patients with melanomas and solid cancers. These studies document that mda-7/IL-24 is well tolerated and demonstrates evidence of significant clinical activity. In these contexts, mda-7/IL-24 represents a unique cytokine gene with potential for therapy of human cancers. The present review focuses on three unique properties of mda-7/IL-24, namely its potent 'bystander antitumor activity', ability to sensitize tumor cells to radiation, and its antiangiogenesis properties. Additionally, an overview of the phase I clinical trial is provided. These studies affirm that mda-7/IL-24 has promise for the management of diverse cancers.

Role of OSGIN1 in mediating smoking-induced autophagy in the human airway epithelium.

Enhanced macroautophagy/autophagy is recognized as a component of the pathogenesis of smoking-induced airway disease. Based on the knowledge that enhanced autophagy is linked to oxidative stress and the DNA damage response, both of which are linked to smoking, we used microarray analysis of the airway epithelium to identify smoking upregulated genes known to respond to oxidative stress and the DNA damage response. This analysis identified OSGIN1 (oxidative stress induced growth inhibitor 1) as significantly upregulated by smoking, in both the large and small airway epithelium, an observation confirmed by an independent small airway microarray cohort, TaqMan PCR of large and small airway samples and RNA-Seq of small airway samples. High and low OSGIN1 expressors have different autophagy gene expression patterns in vivo. Genome-wide correlation of RNAseq analysis of airway basal/progenitor cells showed a direct correlation of OSGIN1 mRNA levels to multiple classic autophagy genes. In vitro cigarette smoke extract exposure of primary airway basal/progenitor cells was accompanied by a dose-dependent upregulation of OSGIN1 and autophagy induction. Lentivirus-mediated expression of OSGIN1 in human primary basal/progenitor cells induced puncta-like staining of MAP1LC3B and upregulation of MAP1LC3B mRNA and protein and SQSTM1 mRNA expression level in a dose and time-dependent manner. OSGIN1-induction of autophagosome, amphisome and autolysosome formation was confirmed by colocalization of MAP1LC3B with SQSTM1 or CD63 (endosome marker) and LAMP1 (lysosome marker). Both OSGIN1 overexpression and knockdown enhanced the smoking-evoked autophagic response. Together, these observations support the concept that smoking-induced upregulation of OSGIN1 is one link between smoking-induced stress and enhanced-autophagy in the human airway epithelium.