The evolution of lung cancer and impact of subclonal selection in TRACERx.

Lung cancer is the leading cause of cancer-associated mortality worldwide1. Here we analysed 1,644 tumour regions sampled at surgery or during follow-up from the first 421 patients with non-small cell lung cancer prospectively enrolled into the TRACERx study. This project aims to decipher lung cancer evolution and address the primary study endpoint: determining the relationship between intratumour heterogeneity and clinical outcome. In lung adenocarcinoma, mutations in 22 out of 40 common cancer genes were under significant subclonal selection, including classical tumour initiators such as TP53 and KRAS. We defined evolutionary dependencies between drivers, mutational processes and whole genome doubling (WGD) events. Despite patients having a history of smoking, 8% of lung adenocarcinomas lacked evidence of tobacco-induced mutagenesis. These tumours also had similar detection rates for EGFR mutations and for RET, ROS1, ALK and MET oncogenic isoforms compared with tumours in never-smokers, which suggests that they have a similar aetiology and pathogenesis. Large subclonal expansions were associated with positive subclonal selection. Patients with tumours harbouring recent subclonal expansions, on the terminus of a phylogenetic branch, had significantly shorter disease-free survival. Subclonal WGD was detected in 19% of tumours, and 10% of tumours harboured multiple subclonal WGDs in parallel. Subclonal, but not truncal, WGD was associated with shorter disease-free survival. Copy number heterogeneity was associated with extrathoracic relapse within 1 year after surgery. These data demonstrate the importance of clonal expansion, WGD and copy number instability in determining the timing and patterns of relapse in non-small cell lung cancer and provide a comprehensive clinical cancer evolutionary data resource.

Preliminary Investigation and Imaging Analysis of Early Lung Cancer Screening Among Petroleum Workers in North China.

BACKGROUND: The detection rate of lung nodules has increased significantly among petroleum workers in North China since the low-dose CT (LDCT) screening has been widely carried out. What's more, the number of confirmed early lung cancers is increasing continuously. Therefore, a great deal of concern for the high risk of lung cancer has been shown among petroleum workers. PURPOSE: To improve the screening efficiency and maximize the benefits of the subjects, the current situation of LDCT lung cancer screening should be understood and the imaging characteristics of early lung cancer should be analyzed for petroleum workers in North China. MATERIALS AND METHODS: Firstly, the dynamic changes of LDCT early lung cancer screening for petroleum workers in North China were analyzed in recent years. Then, the survey data of 3121 petroleum workers was compared with that of 1868 non-petroleum workers, which was analyzed. Finally, 91 patients (129 nodular lung cancer) confirmed by pathology were retrospectively analyzed, and the data of which was compared with the clinical features obtained from survey data above. The imaging characteristics and related factors of different subtypes of lung adenocarcinoma were discussed and analyzed. RESULTS: Lung nodules were found in 810 cases (25.95%) out of 3121 petroleum workers; and the surgery was chosen by 42 patients, 38 of whom were confirmed as lung cancer. Compared with the data of screened petroleum workers, there were more older people and more females as well as a higher proportion of people with family malignancy history, and a lower proportion of smoking people in 91 patients with lung cancer. As the pathological grade of tumor nodules increased, the volume and diameter of nodules gradually increased, and the mean density, maximum density and standard deviation of density also increased (p < 0.001). The volume and diameter of nodules were positively correlated with ages (p < 0.05). CONCLUSION: The occurrence of lung adenocarcinoma is closely related to the family history of malignant tumors, and the constituent ratio of young women without a history of smoking increased significantly. At the same time, the quantitative information obtained by using CT images has important value in predicting its pathological subtypes.

Response to pembrolizumab in a patient with primary lung adenocarcinoma originated from indium lung.

BACKGROUND: Indium is a metal used as a compound called indium-tin oxide for liquid crystal display. Its inhalation causes lung toxicity, resulting in a new occupational lung disease called indium lung. Although the carcinogenicity of indium has been reported in an animal model, its carcinogenicity in humans is unknown. CASE PRESENTATION: This is the first reported case of a primary lung cancer originating from indium lung. In this report, we describe a 46-year-old man with interstitial pneumonia-type indium lung diagnosed 16 years ago. The initial symptom was left chest pain, and computed tomography showed a mass adjacent to the aorta with left pleural effusion. Specimens collected using video-assisted thoracoscopy revealed an adenocarcinoma with a high expression of programmed cell death-ligand 1 (cT4N0M1a stage IVA). Although the lesions showed a remarkable aggressive nature, the patient benefited from pembrolizumab, a monoclonal antibody against programmed cell death 1, which was used as second-line therapy for 2 years. CONCLUSIONS: It is important for clinicians to be aware of lung cancer development in indium-exposed workers or in patients with indium lung, as this could have an aggressive behavior. Treatment with immune checkpoint inhibitors is an option even in patients with interstitial pneumonia-type indium lung.

LINC01089 suppresses lung adenocarcinoma cell proliferation and migration via miR-301b-3p/STARD13 axis.

BACKGROUND: Lung adenocarcinoma (LUAD) is one of the most common cancers with high morbidity and mortality worldwide. Long non-coding RNAs (lncRNAs) serve as tumor promoters or suppressors in the development of various human malignancies, including LUAD. Although long intergenic non-protein coding RNA 1089 (LINC01089) suppresses the progression of breast cancer, its mechanism in LUAD requires further exploration. Thus, we aimed to investigate the underlying function and mechanism of LINC01089 in LUAD. METHODS: The expression of LINC01089 in LUAD and normal cell lines was detected. Functional assays were applied to measure cell proliferation, apoptosis and migration. Besides, mechanism experiments were employed for assessing the interplay among LINC01089, miR-301b-3p and StAR related lipid transfer domain containing 13 (STARD13). Data achieved in this study was statistically analyzed with Student's t test or one-way analysis of variance. RESULTS: LINC01089 expression was significantly down-regulated in LUAD tissues and cells and its overexpression could reduce cell proliferation and migration. Moreover, LINC01089 could regulate STARD13 expression through competitively binding to miR-301b-3p in LUAD. Additionally, rescue assays uncovered that STARD13 depletion or miR-301b-3p overexpression could countervail the restraining effect of LINC01089 knockdown on the phenotypes of LUAD cells. CONCLUSION: LINC01089 served as a tumor-inhibitor in LUAD by targeting miR-301b-3p/STARD13 axis, providing an innovative insight into LUAD therapies. Trial registration Not applicable.

The ADAM17 protease promotes tobacco smoke carcinogen-induced lung tumorigenesis.

Lung cancer is the leading cause of cancer-related mortality, with most cases attributed to tobacco smoking, in which nicotine-derived nitrosamine ketone (NNK) is the most potent lung carcinogen. The ADAM17 protease is responsible for the ectodomain shedding of many pro-tumorigenic cytokines, growth factors and receptors, and therefore is an attractive target in cancer. However, the role of ADAM17 in promoting tobacco smoke carcinogen-induced lung carcinogenesis is unknown. The hypomorphic Adam17ex/ex mice-characterized by reduced global ADAM17 expression-were backcrossed onto the NNK-sensitive pseudo-A/J background. CRISPR-driven and inhibitor-based (GW280264X, and ADAM17 prodomain) ADAM17 targeting was employed in the human lung adenocarcinoma cell lines A549 and NCI-H23. Human lung cancer biopsies were also used for analyses. The Adam17ex/ex mice displayed marked protection against NNK-induced lung adenocarcinoma. Specifically, the number and size of lung lesions in NNK-treated pseudo-A/J Adam17ex/ex mice were significantly reduced compared with wild-type littermate controls. This was associated with lower proliferative index throughout the lung epithelium. ADAM17 targeting in A549 and NCI-H23 cells led to reduced proliferative and colony-forming capacities. Notably, among select ADAM17 substrates, ADAM17 deficiency abrogated shedding of the soluble IL-6 receptor (sIL-6R), which coincided with the blockade of sIL-6R-mediated trans-signaling via ERK MAPK cascade. Furthermore, NNK upregulated phosphorylation of p38 MAPK, whose pharmacological inhibition suppressed ADAM17 threonine phosphorylation. Importantly, ADAM17 threonine phosphorylation was significantly upregulated in human lung adenocarcinoma with smoking history compared with their cancer-free controls. Our study identifies the ADAM17/sIL-6R/ERK MAPK axis as a candidate therapeutic strategy against tobacco smoke-associated lung carcinogenesis.

Circulating markers of cellular immune activation in prediagnostic blood sample and lung cancer risk in the Lung Cancer Cohort Consortium (LC3).

Cell-mediated immune suppression may play an important role in lung carcinogenesis. We investigated the associations for circulating levels of tryptophan, kynurenine, kynurenine:tryptophan ratio (KTR), quinolinic acid (QA) and neopterin as markers of immune regulation and inflammation with lung cancer risk in 5,364 smoking-matched case-control pairs from 20 prospective cohorts included in the international Lung Cancer Cohort Consortium. All biomarkers were quantified by mass spectrometry-based methods in serum/plasma samples collected on average 6 years before lung cancer diagnosis. Odds ratios (ORs) and 95% confidence intervals (CIs) for lung cancer associated with individual biomarkers were calculated using conditional logistic regression with adjustment for circulating cotinine. Compared to the lowest quintile, the highest quintiles of kynurenine, KTR, QA and neopterin were associated with a 20-30% higher risk, and tryptophan with a 15% lower risk of lung cancer (all ptrend < 0.05). The strongest associations were seen for current smokers, where the adjusted ORs (95% CIs) of lung cancer for the highest quintile of KTR, QA and neopterin were 1.42 (1.15-1.75), 1.42 (1.14-1.76) and 1.45 (1.13-1.86), respectively. A stronger association was also seen for KTR and QA with risk of lung squamous cell carcinoma followed by adenocarcinoma, and for lung cancer diagnosed within the first 2 years after blood draw. This study demonstrated that components of the tryptophan-kynurenine pathway with immunomodulatory effects are associated with risk of lung cancer overall, especially for current smokers. Further research is needed to evaluate the role of these biomarkers in lung carcinogenesis and progression.

A novel circular RNA, hsa-circ-0000211, promotes lung adenocarcinoma migration and invasion through sponging of hsa-miR-622 and modulating HIF1-α expression.

Recently, several studies have evaluated the role of circular RNAs in the metastasis and development of multiple cancers. In our earlier microarray-based study, we had reported the aberrant expression of a novel circular RNA, hsa-circ-0000211 in lung adenocarcinoma (LAC) tissues. However, the roles of hsa-circ-0000211 in LAC have not been studied. Here hsa-circ-0000211 expression in the LAC tissues and cell lines was determined by quantitative real-time PCR (qRT-PCR). The function of hsa-circ-0000211 was evaluated by transwell assay and wound healing. Mechanisms of hsa-circ-0000211 was measured by luciferase reporter assay and western blot. Results revealed the expression of hsa-circ-0000211 in the human LAC tissues and LAC cell lines was higher than that in normal tissue and human lung normal epithelial cells, respectively. The knockdown of hsa-circ-0000211 could inhibit the migration and invasion properties of LAC. Furthermore, hsa-circ-0000211 promoted the migration and invasion of LAC by sponging miR-622. Moreover, hsa-circ-0000211 upregulated the HIF1-α expression by targeting miR-622. hsa-circ-0000211 promoted LAC cell migration and invasion by modulating the miR-622/HIF1-α network. Our study demonstrated that hsa-circ-0000211 can be a potential novel therapeutic target for LAC.

TNF-α-dependent lung inflammation upregulates superoxide dismutase-2 to promote tumor cell proliferation in lung adenocarcinoma.

Manganese superoxide dismutase (SOD-2), an important primary antioxidant enzyme located in mitochondria, plays a critical role in tumor progression. Reportedly, the proinflammatory cytokine, tumor necrosis factor (TNF)-α, can increase SOD-2 expression in a human lung adenocarcinoma cell line in vitro, indicating that TNF-α-mediated inflammation may regulate SOD-2 expression, which may be related to cancer promotion. Using a urethane-induced inflammation-driven lung adenocarcinoma (IDLA) mice model, we investigated whether and how TNF-α-mediated inflammation upregulated SOD-2 expression in lung adenocarcinoma. Our results showed that SOD-2 was mostly expressed on surfactant protein-C+ AT-II cells (alveolar type II cell) and tumor cells in IDLA mice, which were surrounded by CD68+ macrophages. Blocking TNF-α-dependent inflammation downregulated SOD-2 expression in inflamed lung tissues at the protumor stage and also inhibited SOD-2 expression in tumor cells in the IDLA model. In human lung adenocarcinoma, both the number of infiltrating CD68+ macrophages and TNF-α expression correlated positively with SOD-2 expression, which is related to lymph node metastasis and TNM stage. We collected the conditioned medium from lipopolysaccharide-activated phorbol myristate acetate-induced THP1 (M1) cells to stimulate A549 and H1299 cells and observed that THP1-M1 upregulated SOD-2 by secreting TNF-α. Blocking SOD-2 expression significantly inhibited TNF-α-induced cell proliferation in A549 and H1299 cells in vitro. Thus, TNF-α-mediated lung inflammation can upregulate SOD-2 expression in lung adenocarcinoma, and macrophages contribute to SOD-2 upregulation by secreting TNF-α.

Risk of lung adenocarcinoma from smoking and radiation arises in distinct molecular pathways.

KRAS mutations of lung adenocarcinoma (LADC) are associated with smoking but little is known on other exposure-oncogene associations. Hypothesizing that different inciting agents may cause different driver mutations, we aimed to identify distinct molecular pathways to LADC, applying two entirely different approaches. First, we examined clinicopathologic features and genomic signatures of environmental exposures in the large LADC Campbell data set. Second, we designed a molecular mechanistic risk model of LADC (M3LADC) that links environmental exposure to incidence risk by mathematically emulating the disease process. This model was applied to incidence data of Japanese atom-bomb survivors which contains information on radiation and smoking exposure. Grouping the clinical data by driver mutations revealed two main distinct molecular pathways to LADC: one unique to transmembrane receptor-mutant patients that displayed robust signatures of radiation exposure and one shared between submembrane transducer-mutant patients and patients with no evident driver mutation that carried the signature of smoking. Consistently, best fit of the incidence data was achieved with a M3LADC with two pathways: in one LADC risk increased with radiation exposure and in the other with cigarette consumption. We conclude there are two main molecular pathways to LADC associated with different environmental exposures. Future molecular measurements in lung cancer tissue of atom-bomb survivors may allow to further test quantitatively the M3LADC-predicted link of radiation to transmembrane receptor mutations. Moreover, the developed molecular mechanistic model showed that for low doses, as relevant e.g. for medical imaging, smokers have the same radiation risk compared with never smokers.

Epithelial-mesenchymal transition markers screened in a cell-based model and validated in lung adenocarcinoma.

BACKGROUND: Re-capture of the differences between tumor and normal tissues observed at the patient level in cell cultures and animal models is critical for applications of these cancer-related differences. The epithelial-mesenchymal transition (EMT) process is essential for tumor migratory and invasive capabilities. Although plenty of EMT markers are revealed, molecular features during the early stages of EMT are poorly understood. METHODS: A cell-based model to induce lung cell (A549) EMT using conditioned medium of in vitro cancer activated fibroblast (WI38) was established. High-throughput sequencing methods, including RNA-seq and miRNA-seq, and advanced bioinformatics methods were used to explore the transcriptome profile transitions accompanying the progression of EMT. We validated our findings with experimental techniques including transwell and immunofluorescence assay, as well as the TCGA data. RESULTS: We have constructed an in vitro cell model to mimic the EMT in patients. We discovered that several new transcription factors were among the early genes (3 h) to respond to cancer micro-environmental cues which could play critical roles in triggering further EMT signals. The early EMT markers also included genes encoding membrane transporters and blood coagulation function. Three of the nine-examined early EMT hallmark genes, GALNT6, SPARC and HES7, were up-regulated specifically in the early stages of lung adenocarcinoma (LUAD) and confirmed by TCGA patient transcriptome data. In addition, we showed that miR-3613, a regulator of EGFR pathway genes, was constantly repressed during EMT progress and indicative of an epithelial miRNA marker. CONCLUSIONS: The CAF-stimulated EMT cell model may recapture some of the molecular changes during EMT progression in clinical patients. The identified early EMT hallmark genes GALNT6, SPARC and HES7and miR-3613 provide new markers and therapeutic targets for LUAD for the further clinical diagnosis and drug screening.

Non-Small-Cell Lung Cancer After Mantle Radiation: A Case Report and Brief Review.

Survivors of childhood and young adult cancer are at risk for developing subsequent malignant neoplasms, including lung cancer. As survival rates in this group continue to improve and patients enter later decades in life, determining the optimal surveillance and counseling strategies with regards to subsequent cancers remains a challenge. In this case report, we present a non-Hodgkin lymphoma survivor who was incidentally found to have non-small-cell lung cancer 30 years after undergoing treatment that included mantle radiation. We discuss the treatment-related risk factors for lung cancer in this population and potential implications for long-term follow-up.

Modulating SIRT1 activity variously affects thymic lymphoma development in mice.

SIRT1 is a protein deacetylase with a broad range of biological functions, many of which are known to be important in carcinogenesis, however much of the literature regarding the role of SIRT1 in cancer remains conflicting. In this study we assessed the effect of SIRT1 on the initiation and progression of thymic T cell lymphomas. We employed mouse strains in which SIRT1 activity was absent or could be reversibly modulated in conjunction with thymic lymphoma induction using either the N-nitroso-N-methylurea (NMU) carcinogenesis or the nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) transgene. Decreased SIRT1 activity reduced the development of thymic lymphomas in the NMU-treated mice but was permissive for the formation of lung adenomas. Conversely, in the NPM-ALK transgenic mice, decreased SIRT1 activity had a modest promoting effect in the development of thymic lymphomas. The results of the work presented here add to the growing body of evidence that sirt1 is neither an outright oncogene nor a tumor suppressor. These opposing results in two models of the same disease suggest that the influence of sirt1 on carcinogenesis may lie in a role in tumor surveillance.

Nested case-control study of telomere length and lung cancer risk among heavy smokers in the ß-Carotene and Retinol Efficacy Trial.

BACKGROUND: Telomeres protect cells from genomic instability. We examined telomere length and lung cancer risk prospectively in heavy smokers. METHODS: In a nested case-control study with 709 cases and 1313 controls, conditional logistic regression was used to evaluate associations between telomere length (global, chromosome 5p, and 13q) and lung cancer risk by histotype, controlling for detailed smoking history. RESULTS: Risks of overall lung cancer and adenocarcinoma were suggestively elevated among individuals with telomere length in the longest tertile. No clear patterns were observed for other histotypes, or for chromosome 5p or 13q telomere length. Associations with adenocarcinoma were strongest among (OR, 95% CI for longest versus shortest tertile): former smokers (2.26, 1.03-4.96), individuals <65 years (2.22, 1.13-4.35), and women (2.21, 0.99-4.93). CONCLUSIONS: Our large study of heavy smokers adds additional evidence that long telomere length prior to diagnosis is associated with risk of lung adenocarcinoma, but not other histotypes.

Elevated mRNA Levels of AURKA, CDC20 and TPX2 are associated with poor prognosis of smoking related lung adenocarcinoma using bioinformatics analysis.

Background and aim: Adenocarcinoma is a very common pathological subtype for lung cancer. We aimed to identify the gene signature associated with the prognosis of smoking related lung adenocarcinoma using bioinformatics analysis. Methods: A total of five gene expression profiles (GSE31210, GSE32863, GSE40791, GSE43458 and GSE75037) have been identified from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were analyzed using GEO2R software and functional and pathway enrichment analysis. Furthermore, the overall survival (OS) and recurrence-free survival (RFS) have been validated using an independent cohort from the Cancer Genome Atlas (TCGA) database. Results: We identified a total of 58 DEGs which mainly enriched in ECM-receptor interaction, platelet activation and PPAR signaling pathway. Then according to the enrichment analysis results, we selected three genes (AURKA, CDC20 and TPX2) for their roles in regulating tumor cell cycle and cell division. The results showed that the hazard ratio (HR) of the mRNA expression of AURKA for OS was 1.588 with (1.127-2.237) 95% confidence interval (CI) (P=0.009). The mRNA levels of CDC20 (HR 1.530, 95% CI 1.086-2.115, P=0.016) and TPX2 (HR 1.777, 95%CI 1.262-2.503, P=0.001) were also significantly associated with the OS. Expression of these three genes were not associated with RFS, suggesting that there might be many factors affect RFS. Conclusion: The mRNA signature of AURKA, CDC20 and TPX2 were potential biomarkers for predicting poor prognosis of smoking related lung adenocarcinoma.

Salivary microbial dysbiosis may predict lung adenocarcinoma: A pilot study.

BACKGROUND: Adenocarcinoma is a more common type of Non-small cell lung cancer (NSCLC). Lung cancer showed a statistically significant increment in the Kamrup Urban district of Assam, Tripura, Sikkim, and Manipur of India. The goal of our pilot study is to identify non-invasive microbial biomarkers to detect lung adenocarcinoma (LAC). MATERIAL AND METHODS: DNA extraction from saliva samples of five LAC patients and five healthy controls was performed by Qiagen DNeasy blood and tissue kit using Lysozyme (3mg/ml) treatment. 16S rRNA genes of distinct regions (V3-V4) were amplified from saliva DNA by PCR. Paired-end sequencing targeting the V3-V4 region of the 16S rRNA gene has been performed on the Illumina MiSeq platform. Raw sequences were analyzed using the QIIME(Quantitative Insights Into Microbial Ecology) software package. RESULTS: Our preliminary results showed that Rothia mucilaginosa, Veillonella dispar, Prevotella melaninogenica, Prevotella pallens, Prevotella copri, Haemophilus parainfluenzae, Neisseria bacilliformis and Aggregatibacter segnis were significantly elevated in saliva of LAC which may serve as potential non-invasive biomarkers for LAC detection. Functional prediction analysis showed that bacterial genes involved in glycosyltransferase, peptidases, amino sugar, and nucleotide sugar metabolism, starch and sucrose metabolism were significantly enriched in LAC. CONCLUSION: These salivary bacteria may contribute to the development of LAC by increasing expression of glycosyltransferase and peptidases. However to understand their role in pathobiology, studies are required to perform in large cohort.

Smoking-associated upregulation of CBX3 suppresses ARHGAP24 expression to activate Rac1 signaling and promote tumor progression in lung adenocarcinoma.

Although tobacco smoking is a risk factor for lung adenocarcinoma (LUAD), the mechanisms by which tobacco smoking induces LUAD development remain elusive. Histone methylation levels in human bronchial epithelial cells have been reported to increase after exposure to cigarettes. In this study, we explored the mechanisms regulating histone methylation in LUAD in response to smoking. We found that the histone H3K9 methylation reader CBX3 was upregulated in current smokers with LUAD, and that CBX3 overexpression promoted LUAD progression. Functional enrichment analyses revealed that CBX3 regulated the activation of Rho GTPases in LUAD. We also found that by forming a complex with TRIM28, TRIM24, and RBBP4, CBX3 repressed the expression of ARHGAP24 and increased the amount of active Rac1 in LUAD cells. Collectively, these results suggest that smoking associated upregulation of CBX3 promotes LUAD progression by activating the ARHGAP24/Rac1 pathway. Hence, the CBX3/ARHGAP24/Rac1 axis may represent a promising therapeutic target in smoking-induced LUAD.

Aggressive early-stage lung adenocarcinoma is characterized by epithelial cell plasticity with acquirement of stem-like traits and immune evasion phenotype.

Lung adenocarcinoma (LUAD) is the main non-small-cell lung cancer diagnosed in ~40-50% of all lung cancer cases. Despite the improvements in early detection and personalized medicine, even a sizable fraction of patients with early-stage LUAD would experience disease relapses and adverse prognosis. Previous reports indicated the existence of LUAD molecular subtypes characterized by specific gene expression and mutational profiles, and correlating with prognosis. However, the biological and molecular features of such subtypes have not been further explored. Consequently, the mechanisms driving the emergence of aggressive LUAD remained unclear. Here, we adopted a multi-tiered approach ranging from molecular to functional characterization of LUAD and used it on multiple cohorts of patients (for a total of 1227 patients) and LUAD cell lines. We investigated the tumor transcriptome and the mutational and immune gene expression profiles, and we used LUAD cell lines for cancer cell phenotypic screening. We found that loss of lung cell lineage and gain of stem cell-like characteristics, along with mutator and immune evasion phenotypes, explain the aggressive behavior of a specific subset of lung adenocarcinoma that we called C1-LUAD, including early-stage disease. This subset can be identified using a 10-gene prognostic signature. Poor prognosis patients appear to have this specific molecular lung adenocarcinoma subtype which is characterized by peculiar molecular and biological features. Our data support the hypothesis that transformed lung stem/progenitor cells and/or reprogrammed epithelial cells with CSC characteristics are hallmarks of this aggressive disease. Such discoveries suggest alternative, more aggressive, therapeutic strategies for early-stage C1-LUAD.

TGFß Signaling Activated by Cancer-Associated Fibroblasts Determines the Histological Signature of Lung Adenocarcinoma.

Invasive lung adenocarcinoma (LADC) can be classified histologically as lepidic, acinar, papillary, micropapillary, or solid. Most LADC tumors manifest several of these histological subtypes, with heterogeneity being related to therapeutic resistance. We report here that in immunodeficient mice, human LADC cells form tumors with distinct histological features, MUC5AC-expressing solid-type or cytokeratin 7 (CK7)-expressing acinar-type tumors, depending on the site of development, and that a solid-to-acinar transition (SAT) could be induced by the tumor microenvironment. The TGFß-Smad signaling pathway was activated in both tumor and stromal cells of acinar-type tumors. Immortalized cancer-associated fibroblasts (CAF) derived from acinar-type tumors induced SAT in 3D cocultures with LADC cells. Exogenous TGFß1 or overexpression of an active form of TGFß1 increased CK7 expression and reduced MUC5AC expression in LADC cells, and knockdown of Tgfb1 mRNA in CAFs attenuated SAT induction. RNA-sequencing analysis suggested that angiogenesis and neutrophil recruitment are associated with SAT in vivo. Our data indicate that CAF-mediated paracrine TGFß signaling induces remodeling of tumor tissue and determines the histological pattern of LADC, thereby contributing to tumor heterogeneity. SIGNIFICANCE: CAFs secrete TGFß to induce a solid-to-acinar transition in lung cancer cells, demonstrating how the tumor microenvironment influences histological patterns and tumor heterogeneity in lung adenocarcinoma.

Potential role of glucosamine-phosphate N-acetyltransferase 1 in the development of lung adenocarcinoma.

Glucosamine-phosphate N-acetyltransferase 1 (GNPNAT1) is a key enzyme associated with glucose metabolism and uridine diphosphate-N-acetylglucosamine biosynthesis. Abnormal GNPNAT1 expression might be associated with carcinogenesis. We analyzed multiple lung adenocarcinoma (LUAD) gene expression databases and verified GNPNAT1 higher expression in LUAD tumor tissues than in normal tissues. Moreover, we analyzed the survival relationship between LUAD patients' clinical status and GNPNAT1 expression, and found higher GNPNAT1 expression in LUAD patients with unfavorable prognosis. We built GNPNAT1 gene co-expression networks and further annotated the co-expressed genes' Gene Ontology (GO) terms, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, and various associated regulatory factors. These co-expression genes' functional networks mainly participate in chromosome segregation, RNA metabolic process, and RNA transport. We analyzed GNPNAT1 genetic alterations and co-occurrence networks, and the functional networks of these genes showed that GNPNAT1 participates in multiple steps of cell cycle transition and in the development of some cancers. We assessed the correlation between GNPNAT1 expression and cancer immune infiltrates and showed that GNPNAT1 expression is correlated with several immune cells, chemokines, and immunomodulators in LUAD. We found that GNPNAT1 correlates with LUAD development and prognosis, laying a foundation for further research, especially in immunotherapy.

Chromobox 4 facilitates tumorigenesis of lung adenocarcinoma through the Wnt/ß-catenin pathway.

Chromobox 4 (CBX4) is a core component of polycomb-repressive complex 1 with important roles in cancer biology and tissue homeostasis. Aberrant expression of CBX4 has been implicated in several human malignancies. However, its role and underlying mechanisms in the tumorigenesis of lung adenocarcinoma (LUAD) have not been defined in vivo. Here, we found that expression of CBX4 was frequently up-regulated in human LUAD samples and correlated with poor patient survival. Importantly, genetic ablation of CBX4 greatly dampened lung tumor formation and improved survival in the KrasG12D/P53L/L (KP) autochthonous mouse model of LUAD. In addition, CBX4 depletion significantly inhibited proliferation and anchorage-independent growth of KP mouse embryonic fibroblasts. Moreover, ectopic CBX4 expression clearly promoted proliferation and anchorage-independent growth in both human and mouse LUAD cells, whereas silencing of CBX4 exerted opposite effects. Mechanistically, CBX4 promoted growth of LUAD cells through activation of the Wnt/ß-catenin pathway. Furthermore, expression levels of CBX4 were positively correlated with ß-catenin in human LUAD samples. In conclusion, our data suggest that CBX4 plays an oncogenic role via the Wnt/ß-catenin pathway and could serve as a potential therapeutic target in LUAD.