Notch in lung development and lung cancer

Umbilical cord mesenchymal stem cells and lung cancer: We should be hopeful or hopeless?

Lung cancer (LC) is one of the leading causes of cancer-caused death that possesses a poor prognosis and low survival rate worldwide. In general, LC is classified into small-cell (SCLC) and non-small-cell carcinoma (NSCLC) (involving 80% of patients). Although chemotherapy, radiotherapy, surgery, and molecular-targeted therapy are considered standard approaches for LC treatment, these options have low success with detrimental effects on the life quality of patients. Ergo, recommending treatment with maximum effectiveness and minimum side effects for LC patients has been a substantial challenge for researchers and clinicians in the present era. Recently, mesenchymal stem cells (MSCs)-based strategies have sparked much interest in preventing or treating numerous illnesses. These multipotent stem cells can be isolated from diverse sources, such as umbilical cord, bone marrow, and adipose tissue. Among these sources, umbilical cord mesenchymal stem cells (UC-MSCs) have been in the spotlight of MSCs-based therapies thanks to their considerable advantages, such as high proliferation ability, low immune reactions and tumorigenesis, and easiness in collection and isolation. Some experimental studies have investigated the functionality of intact UC-MSCs and extracellular vesicles, exosomes, and conditioned medium derived from UC-MSCs, as well as genetically engineered UC-MSCs. In this review, we aimed to highlight the influences of these UMSCs-based methods in LC treatment with cellular and molecular insights.

Clinical significance of PNO1 as a novel biomarker and therapeutic target of hepatocellular carcinoma

The RNA-binding protein PNO1 plays an essential role in ribosome biogenesis. Recent studies have shown that it is involved in tumorigenesis; however, its role in hepatocellular carcinoma (HCC) is not well understood. The purpose of this study was to examine whether PNO1 can be used as a biomarker of HCC and also examine the therapeutic potential of PNO1 knockout for the treatment of HCC. PNO1 expression was upregulated in HCC and associated with poor prognosis. PNO1 expression was positively associated with tumour stage, lymph node metastasis and poor survival. PNO1 expression was significantly higher in HCC compared to that in fibrolamellar carcinoma or normal tissues. Furthermore, HCC tissues with mutant Tp53 expressed higher PNO1 than those with wild-type Tp53. PNO1 knockout suppressed cell viability, colony formation and EMT of HCC cells. Since activation of Notch signalling pathway promotes HCC, we measured the effects of PNO1 knockout on the components of Notch pathway and its targets. PNO1 knockout suppressed Notch signalling by modulating the expression of Notch ligands and their receptors, and downstream targets. PNO1 knockout also inhibited genes involved in surface adhesion, cell cycle, inflammation and chemotaxis. PNO1 knockout also inhibited colony and spheroid formation, cell migration and invasion, and markers of stem cells, pluripotency and EMT in CSCs. Overall, our data suggest that PNO1 can be used as a diagnostic and prognostic biomarker of HCC, and knockout of PNO1 by CRISPR/Cas9 can be beneficial for the management of HCC by targeting CSCs.

Delta-like ligand 3 in small cell lung cancer: Potential mechanism and treatment progress

Small cell lung cancer (SCLC) is one of a pathological type of lung cancer, and it is characterized by invasiveness, high malignancy and refractoriness. The mortality rate of SCLC is significantly higher than other types of lung cancer, and the treatment options for SCLC patients are limited. Delta-like ligand 3 (DLL3) is a Notch signaling ligand that plays a role in regulating the proliferation, development and metastasis of SCLC cells. Mnay studies have shown that DLL3 is overexpressed on the surface of SCLC cells, suggesting that DLL3 is a potential target for SCLC patients. A series of drug trials targeting DLL3 are underway. The Phase III clinical trials of Rova-T, a drug targeting DLL3, have not yielded the expected results. However, other drugs that target DLL3, such as AMG119, AMG757 and DLL3-targeted NIR-PIT, bring new ideas for SCLC treatment. Overall, DLL3 remains a valuable target for SCLC.

SARS-CoV-2 infection alters mitochondrial and cytoskeletal function in human respiratory epithelial cells mediated by expression of spike protein

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, SCV2), which has resulted in higher morbidity and mortality rate than other respiratory viral infections, such as Influenza A virus (IAV) infection. Investigating the molecular mechanisms of SCV2-host infection vs IAV is vital in exploring antiviral drug targets against SCV2. We assessed differential gene expression in human nasal cells upon SCV2 or IAV infection using RNA sequencing. Compared to IAV, we observed alterations in both metabolic and cytoskeletal pathways suggestive of epithelial remodeling in the SCV2-infected cells, reminiscent of pathways activated as a response to chronic injury. We found that spike protein interaction with the epithelium was sufficient to instigate these epithelial responses using a SCV2 spike pseudovirus. Specifically, we found downregulation of the mitochondrial markers SIRT3 and TOMM22. Moreover, SCV2 spike infection increased extracellular acidification and decreased oxygen consumption rate in the epithelium. In addition, we observed cytoskeletal rearrangements with a reduction in the actin-severing protein cofilin-1 and an increase in polymerized actin, indicating epithelial cytoskeletal rearrangements. This study revealed distinct epithelial responses to SCV2 infection, with early mitochondrial dysfunction in the host cells and evidence of cytoskeletal remodeling that could contribute to the worsened outcome in COVID-19 patients compared to IAV patients. These changes in cell structure and energetics could contribute to cellular resilience early during infection, allowing for prolonged cell survival and potentially paving the way for more chronic symptoms. IMPORTANCE COVID-19 has caused a global pandemic affecting millions of people worldwide, resulting in a higher mortality rate and concerns of more persistent symptoms compared to influenza A. To study this, we compare lung epithelial responses to both viruses. Interestingly, we found that in response to SARS-CoV-2 infection, the cellular energetics changed and there were cell structural rearrangements. These changes in cell structure could lead to prolonged epithelial cell survival, even in the face of not working well, potentially contributing to the development of chronic symptoms. In summary, these findings represent strategies utilized by the cell to survive the infection but result in a fundamental shift in the epithelial phenotype, with potential long-term consequences, which could set the stage for the development of chronic lung disease or long COVID-19.

Inhibition of ribosome assembly factor PNO1 by CRISPR/Cas9 technique suppresses lung adenocarcinoma and Notch pathway: Clinical application

Growth is crucially controlled by the functional ribosomes available in cells. To meet the enhanced energy demand, cancer cells re-wire and increase their ribosome biogenesis. The RNA-binding protein PNO1, a ribosome assembly factor, plays an essential role in ribosome biogenesis. The purpose of this study was to examine whether PNO1 can be used as a biomarker for lung adenocarcinoma and also examine the molecular mechanisms by which PNO1 knockdown by CRISPR/Cas9 inhibited growth and epithelial-mesenchymal transition (EMT). The expression of PNO1 was significantly higher in lung adenocarcinoma compared to normal lung tissues. PNO1 expression in lung adenocarcinoma patients increased with stage, nodal metastasis, and smoking. Lung adenocarcinoma tissues from males expressed higher PNO1 than those from females. Furthermore, lung adenocarcinoma tissues with mutant Tp53 expressed higher PNO1 than those with wild-type Tp53, suggesting the influence of Tp53 status on PNO1 expression. PNO1 knockdown inhibited cell viability, colony formation, and EMT, and induced apoptosis. Since dysregulated signalling through the Notch receptors promotes lung adenocarcinoma, we measured the effects of PNO1 inhibition on the Notch pathway. PNO1 knockdown inhibited Notch signalling by suppressing the expression of Notch receptors, their ligands, and downstream targets. PNO1 knockdown also suppressed CCND1, p21, PTGS-2, IL-1α, IL-8, and CXCL-8 genes. Overall, our data suggest that PNO1 can be used as a diagnostic biomarker, and also can be an attractive therapeutic target for the treatment of lung adenocarcinoma.

SCLC: Epidemiology, Risk Factors, Genetic Susceptibility, Molecular Pathology, Screening, and Early Detection

We review research regarding the epidemiology, risk factors, genetic susceptibility, molecular pathology, and early detection of SCLC, a deadly tumor that accounts for 14% of lung cancers. We first summarize the changing incidences of SCLC globally and in the United States among males and females. We then review the established risk factor (i.e., tobacco smoking) and suspected nonsmoking-related risk factors for SCLC, and emphasize the importance of continued effort in tobacco control worldwide. Review of genetic susceptibility and molecular pathology suggests different molecular pathways in SCLC development compared with other types of lung cancer. Last, we comment on the limited utility of low-dose computed tomography screening in SCLC and on several promising blood-based molecular biomarkers as potential tools in SCLC early detection.

Cigarette smoke upregulates Notch-1 signaling pathway and promotes lung adenocarcinoma progression

Notch-1 pathway plays an important role in lung carcinoma, stem cell regulation, cellular communication, growth and differentiation. Cigarette smoke is involved in the regulation of Notch signaling. However, current data regarding the impact of cigarette smoke on the Notch pathway in lung cancer progression are limited. The present study aimed to explore whether cigarette smoke exposure altered Notch-1 pathway in ex-vivo (surgical samples of lung parenchyma from non-smoker and smoker patients with lung adenocarcinoma) and in vitro (adenocarcinoma A549 cell line) approaches. The expression of Notch-1, Jagged-1 and CD133 in surgical samples was evaluated by immunohistochemistry. A549 were exposed to cigarette smoke extracts (2.5% and 5% CSE for 6, 24 and 48 h) and the expression of Notch-1, Jagged-1 and Hes-1 was evaluated by Real-Time PCR and Western Blot (nuclear fractions). Expression and localization of Notch-1, Hes-1, CD133 and ABCG2 were assessed by immunofluorescence. The expression of survivin and Ki-67 was assessed by flow cytometry following CSE exposure and inhibition of Notch-1 signaling. Smokers lung parenchyma exhibited higher expression of Notch-1. CSE exposure increased Notch-1 and Hes-1 gene and nuclear protein expression in A549. Immunofluorescence confirmed higher expression of nuclear Hes-1 in CSE-stimulated A549 cells. CSE increased both survivin and Ki-67 expression and this effect was reverted by inhibition of the Notch-1 pathway. In conclusion, these data show that cigarette smoke may promote adenocarcinoma progression by activating the Notch-1 pathway thus supporting its role as hallmark of lung cancer progression and as a new target for lung cancer treatment.

Multifaceted targeting strategies in cancer against the human notch 3 protein: a computational study

Notch receptors play a significant role in the development and the regulation of cell-fate in several multicellular organisms. For normal differentiation, genomes are essential as their regular roles and play a role in cancer is dysregulated. Notch 3 has been shown to play a major role in lung cancer function and therefore, inhibition of notch 3 protein activation represents a clear plan for cancer treatment. This study accomplished a combined structure- and ligand-based pharmacophore hypothesis to explore novel notch 3 inhibitors. The analysis identified common lead molecule ZINC000013449462 that showed better XP GScore and binding energy score than the reference inhibitor DAPT. The identified lead compound that passed all the druggable characteristics exhibited stable binding. Furthermore, the lead molecule can also form hydrogen and salt bridge interactions with binding site residues Asp1621 and Arg1465 residues, respectively of the active pockets of notch 3 protein. In essence, the inhibitory activity of the hit was validated across 109 NSCLC cell lines by employing a deep neural network algorithm. Our study proposes that ZINC000013449462 would be a possible prototype molecule towards the notch 3 target and further examined by clinical studies to combat NSCLC.

Effect of genetic variation in Notch regulator DTX1 on SCLC prognosis compared with the effect on NSCLC prongosis

Deltex-1 (DTX1) is a negative regulator of the Notch signaling pathway. Here, we investigated the clinical effect of DTX1 rs1732786A > G, which is associated with better prognosis in patients with early-stage non-small cell lung cancer (NSCLC), in 261 patients with small cell lung cancer (SCLC). DTX1 rs1732786A > G was associated with a significantly worse chemotherapy response and lower overall survival in the codominant model (odds ratio = 0.42, 95% confidence interval [CI]: 0.26-0.66, P = 2 × 10^-4 ; hazard ratio = 1.47, 95% CI: 1.17-1.84, P = 0.001, respectively). An in vitro luciferase assay was performed, and the 1732786G allele demonstrated significantly higher promoter activity than the 1732786A allele (P = 2 × 10^-7 ). In summary, DTX1 rs1732786A > G was associated with poor prognosis in patients with SCLC as opposed to patients with NSCLC. KEY POINTS: SIGNIFICANT FINDINGS OF THE STUDY: DTX1 rs1732786A > G was associated with better prognosis in patients with early-stage non-small cell lung cancer (NSCLC) in our previous study. WHAT THIS STUDY ADDS: DTX1 rs1732786A > G was associated with a significantly worse chemotherapy response and lower overall survival in small cell lung cancer (SCLC).

Activation of notch 3/c-MYC/CHOP axis regulates apoptosis and promotes sensitivity of lung cancer cells to mTOR inhibitor everolimus

The mammalian target of rapamycin (mTOR) pathway converges diverse environmental cues to support the lung cancer growth and survival. However, the mTOR-targeted mono-therapy does not achieve expected therapeutic effect. Here, we revealed that fangchinoline (FCL), an active alkaloid that purified from the traditional Chinese medicine Stephania tetrandra S. Moore, enhanced the anti-lung cancer effect of mTOR inhibitor everolimus (EVE). The combination of EVE and FCL was effective to activate Notch 3, and subsequently evoked its downstream target c-MYC. The blockage of Notch 3 signal by the molecular inhibitor of γ-secretase or siRNA of Notch 3 reduced the c-MYC expression and attenuated the combinational efficacy of EVE and FCL on cell apoptosis and proliferation. Moreover, the c-MYC could bind to the C/EBP homologous protein (CHOP) promoter and facilitate CHOP transcription. The conditional genetic deletion of CHOP reduced the apoptosis on lung cancer cells to the same degree as blockage of Notch 3/c-MYC axis, providing further evidence for that the Notch 3/c-MYC axis regulates the transcription of CHOP and finally induces apoptosis upon co-treatment of FCL and EVE in lung cancer cells. Overall, our findings, to the best of our knowledge, firstly link CHOP to Notch 3/c-MYC axis-dependent apoptosis and provide the Notch 3/c-MYC/CHOP activation as a promising strategy for mTOR-targeted combination therapy in lung cancer treatment.

Jagged and Delta-like ligands control distinct events during airway progenitor cell differentiation

Notch signaling regulates cell fate selection during development in multiple organs including the lung. Previous studies on the role of Notch in the lung focused mostly on Notch pathway core components or receptor-specific functions. It is unclear, however, how Jagged or Delta-like ligands collectively or individually (Jag1, Jag2, Dll1, Dll4) influence differentiation of airway epithelial progenitors. Using mouse genetic models we show major differences in Jag and Dll in regulation and establishment of cell fate. Jag ligands had a major impact in balancing distinct cell populations in conducting airways, but had no role in the establishment of domains and cellular abundance in the neuroendocrine (NE) microenvironment. Surprisingly, Dll ligands were crucial in restricting cell fate and size of NE bodies and showed an overlapping role with Jag in differentiation of NE-associated secretory (club) cells. These mechanisms may potentially play a role in human conditions that result in aberrant NE differentiation, including NE hyperplasias and cancer.

Estrogen receptors promote NSCLC progression by modulating the membrane receptor signaling network: a systems biology perspective

Background

Estrogen receptors (ERs) are thought to play an important role in non-small cell lung cancer (NSCLC). However, the effect of ERs in NSCLC is still controversial and needs further investigation. A new consideration is that ERs may affect NSCLC progression through complicated molecular signaling networks rather than individual targets. Therefore, this study aims to explore the effect of ERs in NSCLC from the perspective of cancer systems biology.

Methods

The gene expression profile of NSCLC samples in TCGA dataset was analyzed by bioinformatics method. Variations of cell behaviors and protein expression were detected in vitro. The kinetic process of molecular signaling network was illustrated by a systemic computational model. At last, immunohistochemical (IHC) and survival analysis was applied to evaluate the clinical relevance and prognostic effect of key receptors in NSCLC.

Results

Bioinformatics analysis revealed that ERs might affect many cancer-related molecular events and pathways in NSCLC, particularly membrane receptor activation and signal transduction, which might ultimately lead to changes in cell behaviors. Experimental results confirmed that ERs could regulate cell behaviors including cell proliferation, apoptosis, invasion and migration; ERs also regulated the expression or activation of key members in membrane receptor signaling pathways such as epidermal growth factor receptor (EGFR), Notch1 and Glycogen synthase kinase-3β/β-Catenin (GSK3β/β-Catenin) pathways. Modeling results illustrated that the promotive effect of ERs in NSCLC was implemented by modulating the signaling network composed of EGFR, Notch1 and GSK3β/β-Catenin pathways; ERs maintained and enhanced the output of oncogenic signals by adding redundant and positive-feedback paths into the network. IHC results echoed that high expression of ERs, EGFR and Notch1 had a synergistic effect on poor prognosis of advanced NSCLC.

Conclusions

This study indicated that ERs were likely to promote NSCLC progression by modulating the integrated membrane receptor signaling network composed of EGFR, Notch1 and GSK3β/β-Catenin pathways and then affecting tumor cell behaviors. It also complemented the molecular mechanisms underlying the progression of NSCLC and provided new opportunities for optimizing therapeutic scheme of NSCLC.

Taking SCLC on a Bad LSD(1) Trip One NOTCH Further

Small cell lung cancer (SCLC) is an aggressive form of lung cancer for which therapeutic options are very limited. A new study (Augert et al. Sci. Signal. 2019;12:eaau2922) shows that inhibition of the LSD1 demethylase can induce derepression of NOTCH receptor genes and subsequent activation of the NOTCH pathway, potently suppressing the growth of SCLC.

Notch promotes DNMT-mediated hypermethylation of Klotho leads to COPD-related inflammation

AIM

Klotho expression significantly declines in alveolar macrophages and airway epithelial cells in chronic obstructive pulmonary disease (COPD) patients, and cigarette smoke extract dramatically inhibits the expression and secretion of α-Klotho. This suggests that the silencing of Klotho is the major factor promoting COPD related inflammatory responses. This study aims to investigate the mechanism of Klotho downregulation and its effect on the inflammatory cytokines secretion and cell apoptosis.

METHODS

Expression of DNA methyltransferases (DNMTs) and Notch signaling activation were quantified in MH-S and 16HBE cells stimulated with cigarette smoke extract (CSE) solution. Specific inhibitors of DNMTs or Notch pathway were added together with CSE into treated and control cells. Inflammatory cytokines, cell viability and cell death were determined to explore the effect of Klotho on COPD related inflammation.

RESULTS

CSE treatment statistically increased the level of DNMTs expression, Klotho promoter methylation, and activated the Notch signaling pathway. Notch signal activation played a critical role in the process of modification of Klotho promoter methylation. The inhibition of DNMTs and Notch pathway rescued Klotho levels and inhibited inflammation and cell apoptosis after CSE treatment.

CONCLUSION

Notch-mediated Klotho hypermethylation inhibited Klotho expression, which promoted inflammatory response and cell apoptosis that were associated with the development of COPD.

Relationship between the upregulation of Notch1 signaling and the clinical characteristics of patients with papillary thyroid carcinoma in East Asia: a systematic review and meta-analysis

Background

Many studies have aimed to clarify the relationship between Notch1 signaling and papillary thyroid carcinoma (PTC), but the results have been inconsistent to date. In the present study, a systematic review and meta-analysis were performed to analyze the relationship between Notch1 signaling and the clinical characteristics of PTC.

Methods

Literature databases, including PubMed (Medline), Embase and China National Knowledge Infrastructure, were searched for relevant studies from inception to April 2018. A total of five studies, including 421 patients with PTC from China and South Korea, were included in the meta-analysis.

Results

The results revealed that the upregulation of Notch1 signaling was positively correlated with lymph node metastasis in patients with PTC (OR = 3.25, 95% CI 1.14–9.23, P = 0.03). Additionally, positive correlations were found between Notch1 signaling and tumor size (OR = 4.34, 95% CI 1.66–11.38, P = 0.003), capsular invasion (OR = 3.49, 95% CI 1.90–6.41, P < 0.0001) and clinical stage of PTC (OR = 2.31, 95% CI 1.05–5.11, P = 0.04).

Conclusions

The Notch1 signaling pathway may play a catalytic role in the progression of PTC, and upregulation of Notch1 signaling may have significant predictive value for the clinical prognosis of PTC.

Selective activation and proliferation of a quiescent stem cell population in the neuroepithelial body microenvironment

BACKGROUND

The microenvironment (ME) of neuroepithelial bodies (NEBs) harbors densely innervated groups of pulmonary neuroendocrine cells that are covered by Clara-like cells (CLCs) and is believed to be important during development and for adult airway epithelial repair after severe injury. Yet, little is known about its potential stem cell characteristics in healthy postnatal lungs.

METHODS

Transient mild lung inflammation was induced in mice via a single low-dose intratracheal instillation of lipopolysaccharide (LPS). Bronchoalveolar lavage fluid (BALF), collected 16 h after LPS instillation, was used to challenge the NEB ME in ex vivo lung slices of control mice. Proliferating cells in the NEB ME were identified and quantified following simultaneous LPS instillation and BrdU injection.

RESULTS

The applied LPS protocol induced very mild and transient lung injury. Challenge of lung slices with BALF of LPS-treated mice resulted in selective Ca²⁺-mediated activation of CLCs in the NEB ME of control mice. Forty-eight hours after LPS challenge, a remarkably selective and significant increase in the number of divided (BrdU-labeled) cells surrounding NEBs was observed in lung sections of LPS-challenged mice. Proliferating cells were identified as CLCs.

CONCLUSIONS

A highly reproducible and minimally invasive lung inflammation model was validated for inducing selective activation of a quiescent stem cell population in the NEB ME. The model creates new opportunities for unraveling the cellular mechanisms/pathways regulating silencing, activation, proliferation and differentiation of this unique postnatal airway epithelial stem cell population.

Time-resolved proteome profiling of normal lung development

Biochemical networks mediating normal lung morphogenesis and function have important implications for ameliorating morbidity and mortality in premature infants. Although several transcript-level studies have examined normal lung development, corresponding protein-level analyses are lacking. Here we performed proteomics analysis of murine lungs from embryonic to early adult ages to identify the molecular networks mediating normal lung development. We identified 8,932 proteins, providing a deep and comprehensive view of the lung proteome. Analysis of the proteomics data revealed discrete modules and the underlying regulatory and signaling network modulating their expression during development. Our data support the cell proliferation that characterizes early lung development and highlight responses of the lung to exposure to a nonsterile oxygen-rich ambient environment and the important role of lipid (surfactant) metabolism in lung development. Comparison of dynamic regulation of proteomic and recent transcriptomic analyses identified biological processes under posttranscriptional control. Our study provides a unique proteomic resource for understanding normal lung formation and function and can be freely accessed at Lungmap.net.

C3orf21 ablation promotes the proliferation of lung adenocarcinoma, and its mutation at the rs2131877 locus may serve as a susceptibility marker

In this study, we investigated the role of C3orf21 gene polymorphism at the rs2131877 locus and its contribution to lung adenocarcinoma pathogenesis. Normal lung and tumor tissue sections were collected from fifteen patients with lung adenocarcinoma for chromosome 3 open reading frame 21 (C3orf21) genotype analysis. In addition, a retrospective analysis was performed to assess the association between C3orf21 genotype and tumor markers from patient samples used in our previously published study. In parallel, we also manipulated C3orf21 gene expression either by overexpressing or ablating it in a MSTO-211H human lung cancer cell line to further understand its contribution to cell proliferation, apoptosis and migration. Our results indicated that the patients with smoking history had a significantly increased mutation (rs2131877 T/C+C/C genotype) rate (p = 0.025), in addition to higher values for the CYF211 and NSE tumor markers (p = 0.014 and p = 0.031, respectively). The retrospective analysis also confirmed that the NSE marker value was higher in patients with a C3orf21 rs2131877 T/C+C/C genotype. Furthermore, our in vitro data indicated that C3orf21 ablation promoted lung cancer cell proliferation, inhibited apoptosis and accelerated cell migration. Overall, our study concluded that C30rf21 rs 2131877 T/C+C/C genotype patients may experience increased nicotine addiction and that C30rf21 can likely serve as a susceptibility marker for lung adenocarcinoma with a higher degree of malignancy.

Antitumor activity of Notch‑1 inhibition in human colorectal carcinoma cells

This study investigated the roles of Notch-1 in colorectal carcinoma, to assess the mechanisms. The expression of Notch-1 and its ligand-Jagged1 was detected in human colorectal carcinoma, colorectal adenoma, paracancerous tissue and normal colorectal tissue by immunohistochemistry. Colorectal carcinoma cell lines were utilized to confirm the expression of Notch-1 in colorectal carcinoma cells. Lentiviral-encoding Notch-1-siRNA, as well as Notch-1 inhibitor was employed to silence Notch-1 expression and to inhibit Notch-1 activity in HT29 cells, respectively. As evidenced, Notch-1 and Jagged1 were highly expressed in colorectal carcinoma and colorectal adenoma tissues, compared with those in paracancerous tissue and normal colorectal tissue. However, the expression of Notch-1 and Jagged1 was comparable in colorectal carcinoma and colorectal adenoma tissues, and in paracancerous and normal colorectal tissues. After screening colorectal carcinoma cell lines, Notch-1 was extensively expressed in COLO 205, HT29, SW480 and SW1116 cells, but slightly expressed in LoVo cells. Subsequently, HT29 cell line was selected to investigate the roles of Notch-1 in tumor cell growth and apoptosis. Lenti-viral encoding Notch-1 siRNA significantly decreased Notch-1 expression, inhibited cell growth, arrested the cell cycle at G1 phase and promoted apoptosis. These effects were further confirmed by the Notch-1 inhibitor DAPT. Additionally, we evidenced that Notch-1 silence promoted P21 and PUMA expression in HT29 cells. Taken together, Notch-1 is an oncogene in colorectal carcinoma and the inhibition of Notch-1 could delay the cell growth and promote apoptosis in colorectal cancer.

[Mechanism of Chlorogenic Acid in Apoptotic Regulation through Notch1 Pathway in Non-small Cell Lung Carcinoma in Animal Level]

背景与目的

计算机断层扫描（computed tomography, CT）随访评估结节体积及密度变化是临床针对不定性肺结节采用的常用策略。在保证测量精度前提下降低CT剂量是需要考虑的问题。本研究旨在评估不同管电流及重建算法对肺体模结节容积定量及CT值测量的影响。

方法

应用64排螺旋CT，管电压120kV，7种管电流（10 mA、20 mA、50 mA、80 mA、100 mA、150 mA、350 mA）对肺结节体模进行扫描，采用滤波反投影（filtered back projection, FBP）、自适应迭代重建（ASIR: 30%, 50%, 80%）算法进行重建，获取28套CT图像。应用肺结节分析软件对3种直径（2.5 mm, 5 mm, 10 mm）、三种CT值（-100 HU, 60 HU, 100 HU）共9个球型结节测量容积及平均CT值数据。应用重复测量方差分析评估不同管电流及原始数据重建算法对容积及CT值测量的影响。

结果

直径为2.5 mm结节的容积测量相对误差（100.8%±28%）及三维CT值绝对误差（-756±80）HU最大；直径为5 mm及10 mm结节的容积相对误差小[(-0.9%±1.1%)vs(0.9%±1.4%)]，但CT值绝对误差大[(-243±26)HU vs(-129±7)HU]。针对直径为5 mm及10 mm结节使用重复测量方差分析结果显示，应用不同管电流及原始数据重建算法时容积测量相对误差没有显著性差异（F=5.60, P=0.10 vsF=11.13, P=0.08），三维CT值的绝对误差有显著影响（F=34.79, P < 0.001 vsF=156.14, P < 0.001）。

结论

不同管电流及重建算法对直径5mm及10 mm的结节容积定量影响很小，因此较低管电流及迭代重建算法可以应用在5 mm以上肺结节的CT随访中。结节分析软件提供的平均CT值与标准CT值在不同大小、密度结节中均具有较大误差，不能应用于临床。

Prognostic roles of mRNA expression of notch receptors in non-small cell lung cancer

Notch signalling is aberrantly activated in human non-small cell lung cancer (NSCLC). Nevertheless, the prognostic roles of mRNA expression of four Notch receptors in NSCLC patients remain elusive. In this report, we reported the prognostic roles of Notch receptors in a total of 1,926 NSCLC patients through “The Kaplan-Meier plotter” (KM plotter) database which is capable to assess the effect of 22,277 genes on survival of NSCLC patients. We found that mRNA high expression level of Notch1 was associated with better overall survival (OS) for all NSCLC patients, hazard ratio (HR) 0.78 (0.69-0.89), p=0.00019, better OS in adenocarcinoma (Ade) patients, HR 0.59 (0.46-0.75), p=1.5e-05, as well as in squamous cell carcinoma (SCC) patients, HR 0.78 (0.62-0.99), p=0.044. mRNA high expression levels of Notch2 and Notch3 were associated with worsen OS for all NSCLC patients, as well as in Ade, but not in SCC patients. mRNA high expression level of Notch4 was not found to be associated with to OS for all NSCLC patients. In addition, mRNA high expression levels of Notch2, Notch3, but Notch4 are significantly associated with the NSCLC patients who have different smoking status. Our results indicate that mRNA expression of Notch receptors may have distinct prognostic values in NSCLC patients. These results will benefit for developing tools to accurately predict the prognosis of NSCLC patients.

Synergistic Effect of Notch-3-Specific Inhibition and Paclitaxel in Non-Small Cell Lung Cancer (NSCLC) Cells Via Activation of The Intrinsic Apoptosis Pathway

BACKGROUND Lung cancers are resistant to conventional chemotherapeutic interventions such as paclitaxel. Notch signaling is crucial in the chemoresistance of lung cancer cells. The Notch inhibitor gamma-secretase inhibitor (GSI) inhibits the Notch signaling pathway. MATERIAL AND METHODS Here, we evaluated how Notch-3 inhibition by GSI can enhance the sensitivity of lung cancer cells to paclitaxel. To study how Notch-3-specific inhibition affects non-small cell lung cancer (NSCLC), we compared the cell viability, apoptosis, and colony formation of A549 and H1299 cells treated with Notch-3 siRNA and GSI. RESULTS The expression levels of Notch-3 or Notch intracellular domain 3 (NICD3) and apoptosis-related proteins were measured and compared between different groups. Notch-3 was significantly overexpressed in both cell lines, and Notch-3 expression was elevated after paclitaxel treatment, indicating activation of the Notch signaling pathway. Inhibition of the Notch signaling pathway by GSI and Notch-3 siRNA reduced cell proliferation and induced apoptosis in A549 and H1299 cells, thereby boosting sensitivity of the cell lines to paclitaxel. Concomitant treatment with paclitaxel and GSI or siRNA downregulated Bcl-2 expression and upregulated Bax expression levels. CONCLUSIONS These results indicate a synergistic effect of Notch-3-specific inhibition and paclitaxel through alteration of the intrinsic apoptosis pathway, which was involved in Notch-3-induced chemoresistance in NSCLC cells, and GSI inhibited Notch-3-induced chemoresistance in a concentration-dependent manner. This approach that combines Notch-3-specific inhibition and paclitaxel would be likely to apply in NSCLC.

Expression of Notch Gene and Its Impact on Survival of Patients with Resectable Non-small Cell Lung Cancer

BACKGROUND: Notch signaling has been demonstrated to frequently participate in the process of lung carcinogenesis. This study aimed to search Notch expression in non-small cell lung cancer (NSCLC) and its impact on survival.

METHODS: From 2001 to 2011, patients with diagnosis of NSCLC who received surgical resection were included. The expression of Notch gene was assessed by real-time polymerase chain reaction (RT-PCR). Clinical characteristics, histological types, disease stages, and outcomes were analyzed.

RESULTS: Ninety-seven patients with NSCLC being explored the expression of Notch gene (Notch1 - 4). Seventy-five patients (77.3%) were adenocarcinoma. Patients with adenocarcinoma had higher expression of Notch2 than other histology types (p < 0.001). Otherwise, patients with squamous cell carcinoma had relative higher expression of Notch1 and Notch3 expression (p = 0.014 and p = 0.032, respectively). Notch2 expression increased associated with patients with more advanced lung cancer stage. Patients who had cancer recurrence also had higher Notch2 expression (p = 0.008). The patient group with lung adenocarcinoma of both high Notch1 and Notch3 expression had a shorter median disease-free survival (DFS) (both high v.s both low: DFS, median, 7.2 v.s 25.3 months, p = 0.03). However, the expression of Notch gene had no impact on overall survival.

CONCLUSIONS: Patients with lung adenocarcinoma had higher Notch2 expression. Patients with higher Notch2 expression also had higher rate of cancer recurrence. Both higher Notch1 and Notch3 expression was associated with poor prognosis in lung adenocarcinoma.

Selective gene expression analysis of the neuroepithelial body microenvironment in postnatal lungs with special interest for potential stem cell characteristics

BACKGROUND

The pulmonary neuroepithelial body (NEB) microenvironment (ME) consists of innervated cell clusters that occur sparsely distributed in the airway epithelium, an organization that has so far hampered reliable selective gene expression analysis. Although the NEB ME has been suggested to be important for airway epithelial repair after ablation, little is known about their potential stem cell characteristics in healthy postnatal lungs. Here we report on a large-scale selective gene expression analysis of the NEB ME.

METHODS

A GAD67-GFP mouse model was used that harbors GFP-fluorescent NEBs, allowing quick selection and pooling by laser microdissection (LMD) without further treatment. A panel of stem cell-related PCR arrays was used to selectively compare mRNA expression in the NEB ME to control airway epithelium (CAE). For genes that showed a higher expression in the NEB ME, a ranking was made based on the relative expression level. Single qPCR and immunohistochemistry were used to validate and quantify the PCR array data.

RESULTS

Careful optimization of all protocols appeared to be essential to finally obtain high-quality RNA from pooled LMD samples of NEB ME. About 30% of the more than 600 analyzed genes showed an at least two-fold higher expression compared to CAE. The gene that showed the highest relative expression in the NEB ME, Delta-like ligand 3 (Dll3), was investigated in more detail. Selective Dll3 gene expression in the NEB ME could be quantified via single qPCR experiments, and Dll3 protein expression could be localized specifically to NEB cell surface membranes.

CONCLUSIONS

This study emphasized the importance of good protocols and RNA quality controls because of the, often neglected, fast RNA degradation in postnatal lung samples. It was shown that sufficient amounts of high-quality RNA for reliable complex gene expression analysis can be obtained from pooled LMD-collected NEB ME samples of postnatal lungs. Dll3 expression, which has also been reported to be important in high-grade pulmonary tumor-initiating cells, was used as a proof-of-concept to confirm that the described methodology represents a promising tool for further unraveling the molecular basis of NEB ME physiology in general, and its postnatal stem cell capacities in particular.

Crosstalk of LKB1- and PTEN-regulated signals in liver morphogenesis and tumor development

Liver kinase B 1 (LKB1 or STK11) and phosphatase and tensin homologue deleted on chromosome 10 (PTEN) are two tumor suppressors that regulate the mammalian target of rapamycin signaling pathway. Deletion studies show that loss of either Lkb1 (Lkb^+/–) or Pten (Pten^loxP/loxP; Alb‐Cre⁺) leads to liver injury and development of hepatocarcinoma. In this study, we investigated the crosstalk of LKB1 and PTEN loss during tumorigenesis and liver development. We show that haplo‐insufficiency of Lkb1 in the liver leads to advanced tumor development in Pten‐null mice (Pten^loxP/loxP; Lkb^loxP/+; Alb‐Cre⁺). Our analysis shows that LKB1 and PTEN interact with each other in their regulation of fatty acid synthase as well as p21 expression. The combined loss of LKB1 and PTEN (Pten^loxP/loxP; Lkb^loxP/loxP; Alb‐Cre⁺) also leads to the inability to form zonal structures in the liver. The lack of metabolic zonal structures is consistent with the inability of the livers to store glycogen as well as elevated plasma bilirubin and alanine aminotransferase, indicative of liver dysfunction. These structural and functional defects are associated with cytoplasm distribution of a canalicular membrane protein multidrug resistant protein 2, which is responsible for clearing bilirubin. This observed regulation of multidrug resistant protein 2 by LKB1 likely contributes to the lack of cellular polarity and the early lethality phenotype associated with the homozygous loss of Lkb1 alone or in combination with Pten. Finally, Pten deletion does not rescue the precocious ductal plate formation reported for Lkb1‐deleted livers. Conclusion: Our study dissected the functional and molecular crosstalk of PTEN and LKB1 and elucidated key molecular targets for such interactions. (Hepatology Communications 2017;1:153‐167)

Nitrosothiol-Trapping-Based Proteomic Analysis of S-Nitrosylation in Human Lung Carcinoma Cells

Nitrosylation of cysteines residues (S-nitrosylation) mediates many of the cellular effects of nitric oxide in normal and diseased cells. Recent research indicates that S-nitrosylation of certain proteins could play a role in tumor progression and responsiveness to therapy. However, the protein targets of S-nitrosylation in cancer cells remain largely unidentified. In this study, we used our recently developed nitrosothiol trapping approach to explore the nitrosoproteome of human A549 lung carcinoma cells treated with S-nitrosocysteine or pro-inflammatory cytokines. Using this approach, we identified about 300 putative nitrosylation targets in S-nitrosocysteine-treated A549 cells and approximately 400 targets in cytokine-stimulated cells. Among the more than 500 proteins identified in the two screens, the majority represent novel targets of S-nitrosylation, as revealed by comparison with publicly available nitrosoproteomic data. By coupling the trapping procedure with differential thiol labeling, we identified nearly 300 potential nitrosylation sites in about 150 proteins. The proteomic results were validated for several proteins by an independent approach. Bioinformatic analysis highlighted important cellular pathways that are targeted by S-nitrosylation, notably, cell cycle and inflammatory signaling. Taken together, our results identify new molecular targets of nitric oxide in lung cancer cells and suggest that S-nitrosylation may regulate signaling pathways that are critically involved in lung cancer progression.

Expression of activated Notch1 and Hey1 in papillary thyroid carcinoma

AIMS

The Notch signalling pathway is involved in normal development as well as tumorigenesis. However, it is unclear whether Notch activation is related to diverse clinicopathological factors in papillary thyroid carcinoma (PTC).

METHODS AND RESULTS

We examined the relationship between clinicopathological factors and the expression of activated Notch1 and Hey1, which are indicators of Notch signalling pathway activation, in 109 PTC cases. Activated Notch1 showed strong, moderate and weak expression in 23, 48 and 36 cases, respectively. Its expression was related significantly to histopathological variants (P = 0.007), lymph node metastasis (P = 0.016), BRAF mutation (P = 0.036) and extent of surgery (P = 0.014). Hey1 immunostaining could be divided into two groups: positive and negative, with 26 and 83 cases, respectively. Its expression was related significantly to histopathological variants (P = 0.026), extrathyroidal extension (P = 0.005), BRAF mutation (P = 0.048) and recurrence or soft tissue metastasis (P = 0.000). Multivariate analysis revealed that tumour size (>1 cm), Hey1 immunoreactivity and the presence of lymph node metastasis were associated significantly with recurrence or soft tissue metastasis (odds ratio = 7.38, 4.28 and 12.00, respectively).

CONCLUSIONS

Thus, we found that activation of Notch signalling was correlated significantly with clinicopathological parameters. Therefore, Notch signalling could be a useful prognostic marker in patients with PTC.

Notch Signaling Components: Diverging Prognostic Indicators in Lung Adenocarcinoma

Non-small-cell lung cancer (NSCLC) is a lethal and aggressive malignancy. Currently, the identities of prognostic and predictive makers of NSCLC have not been fully established. Dysregulated Notch signaling has been implicated in many human malignancies, including NSCLC. However, the prognostic value of measuring Notch signaling and the utility of developing Notch-targeted therapies in NSCLC remain inconclusive. The present study investigated the association of individual Notch receptor and ligand levels with lung adenocarcinoma (ADC) and squamous cell carcinoma (SCC) prognosis using the Kaplan-Meier plotte database. This online database encompasses 2437 lung cancer samples. Hazard ratios with 95% confidence intervals were calculated. The results showed that higher Notch1, Notch2, JAG1, and DLL1 mRNA expression predicted better overall survival (OS) in lung ADC, but showed no significance in SCC patients. Elevated Notch3, JAG2, and DLL3 mRNA expression was associated with poor OS of ADC patients, but not in SCC patients. There was no association between Notch4 and OS in either lung ADC or SCC patients. In conclusion, the set of Notch1, Notch2, JAG1, DLL1 and that of Notch3, JAG2, DLL3 played opposing prognostic roles in lung ADC patients. Neither set of Notch receptors and ligands was indicative of lung SCC prognosis. Notch signaling could serve as promising marker to predict outcomes in lung ADC patients. The distinct features of lung cancer subtypes and Notch components should be considered when developing future Notch-targeted therapies.

Evaluation of role of Notch3 signaling pathway in human lung cancer cells

There is still a debate on the extent to which Notch3 signaling is involved in lung carcinogenesis and whether such function is dependent on cancer type or not.

PURPOSE

To evaluate Notch3 expression in different types of human lung cancer cells.

METHODS

Notch3 was detected in human lung cancer cell lines and in tissues. Then, small interfering RNA (siRNA) was used to down-regulate the expression of Notch3 in H69AR small cell lung carcinoma (SCLC) cells; two non-small cell lung carcinoma (NSCLC) cells; A549 adenocarcinoma (ADC); and H2170 squamous cell carcinoma (SCC). In addition, Notch3 intracellular domain (N3ICD) plasmid was transfected into H1688 human SCLC cells. We observed the effect of deregulating Notch3 signaling on the following cell properties: Notch-related proteins, cell morphology, adhesion, epithelial-mesenchymal transition (EMT), motility, proliferation and neuroendocrine (NE) features of SCLC.

RESULTS

Notch3 is mainly expressed in NSCLC, and the expression of Notch1, Hes1 and Jagged1 is affected by Notch3. Notch3 has opposite functions in SCLC and NSCLC, being a tumor suppressor in the former and tumor promoting in the latter, in the context of cell adhesion, EMT and motility. Regarding cell proliferation, we found that inhibiting Notch3 in NSCLC decreases cell proliferation and induces apoptosis in NSCLC. Notch3 has no effect on cell proliferation or NE features of SCLC.

CONCLUSION

Notch3 signaling in lung carcinoma is dependent on cell type. In SCLC, Notch3 behaves as a tumor suppressor pathway, while in NSCLC it acts as a tumor-promoting pathway.

Interaction of Wnt5a with Notch1 is Critical for the Pathogenesis of Psoriasis

Background

Psoriasis is characterized by uncontrolled hyperproliferation, aberrant differentiation, and dermal infiltration of immune cells. Recent studies have reported that Wnt5a and Notch1 signaling are altered in psoriatic skin lesions.

Objective

We aimed to investigate the interaction of Wnt5a with Notch 1 with respect to inflammation-mediated epidermal hyperproliferation in psoriasis.

Methods

Expression of Wnt5a and Notch1 signaling-related proteins were examined in psoriatic skin biopsies. Wnt5a was upregulated in human keratinocytes by treating the cells with its recombinant form (rWnt5a).

Results

In psoriatic lesions, expression of Wnt5a increased while that of Notch1 decreased when compared to that in non-lesional and normal skin. Treatment with rWnt5a increased the proliferation of keratinocytes and increased their secretion of interleukin (IL)-23, IL-12, and tumor necrosis factor (TNF)-α. Further, exposure of keratinocytes to IL-1α, TNF-α, transforming growth factor-α, and interferon-γ downregulated Notch1 as well as HES 1, which is downstream to Notch1, but increased the Wnt5a levels. The upregulated Wnt5a in keratinocytes downregulated both Notch1 and HES1.

Conclusion

Our data suggest that Wnt5a and Notch1 signaling exert counteracting influences on each other and are involved, in part, in the pathomechanism of psoriasis.

Epidermal growth factor receptor status and Notch inhibition in non-small cell lung cancer cells

BACKGROUND

Notch may behave as an oncogene or a tumor suppressor gene in lung cancer cells. Notch receptor undergoes cleavage by enzymes, including γ-secretase, generating the active Notch intracellular domain (NICD). The aim of the present study was to investigate the effect of DAPT, a γ-secretase inhibitor, in non-small cell lung cancer (NSCLC) cells, as well as the impact of epidermal growth factor (EGF) that is over-expressed by NSCLC cells, on Notch signaling. H23, A549, H661 and HCC827 human NSCLC cell lines were used, expressing various NICD and EGF receptor (EGFR) protein levels.

RESULTS

DAPT decreased the number of H661 cells in a concentration-dependent manner, while it had a small effect on H23 and A549 cells and no effect on HCC827 cells that carry mutated EGFR. Notch inhibition did not affect the stimulatory effect of EGF on cell proliferation, while EGF prevented DAPT-induced NICD decrease in H23 and H661 cells. The type of cell death induced by DAPT seems to depend on the cell type.

CONCLUSIONS

Our data indicate that inhibition of Notch cleavage may not affect cell number in the presence of EGFR mutations and that EGFR may affect Notch signalling suggesting that a dual inhibition of these pathways might be promising in NSCLC.

Aberrantly expressed miR-582-3p maintains lung cancer stem cell-like traits by activating Wnt/β-catenin signalling

Cancer stem cells (CSCs) are involved in tumorigenesis, tumour recurrence and therapy resistance and Wnt signalling is essential for the development of the biological traits of CSCs. In non-small cell lung carcinoma (NSCLC), unlike in colon cancer, mutations in β-catenin and APC genes are uncommon; thus, the mechanism underlying the constitutive activation of Wnt signalling in NSCLC remains unclear. Here we report that miR-582-3p expression correlates with the overall- and recurrence-free-survival of NSCLC patients, and miR-582-3p has an activating effect on Wnt/β-catenin signalling. miR-582-3p overexpression simultaneously targets multiple negative regulators of the Wnt/β-catenin pathway, namely, AXIN2, DKK3 and SFRP1. Consequently, miR-582-3p promotes CSC traits of NSCLC cells in vitro and tumorigenesis and tumour recurrence in vivo. Antagonizing miR-582-3p potently inhibits tumour initiation and progression in xenografted animal models. These findings suggest that miR-582-3p mediates the constitutive activation of Wnt/β-catenin signalling, likely serving as a potential therapeutic target for NSCLC.

Despite the absence of frequent mutations of key components of Wnt/β-catenin signalling, this pathway is often constitutively activated in non-small cell lung carcinoma. In this study, the authors demonstrate the inhibitory effect of miR-582-3p on negative regulators of the Wnt/β-catenin pathway which is consequently triggered to sustain lung tumour growth.

Molecular mechanisms underlying variations in lung function: a systems genetics analysis

BACKGROUND

Lung function measures reflect the physiological state of the lung, and are essential to the diagnosis of chronic obstructive pulmonary disease (COPD). The SpiroMeta-CHARGE consortium undertook the largest genome-wide association study (GWAS) so far (n=48,201) for forced expiratory volume in 1 s (FEV1) and the ratio of FEV1 to forced vital capacity (FEV1/FVC) in the general population. The lung expression quantitative trait loci (eQTLs) study mapped the genetic architecture of gene expression in lung tissue from 1111 individuals. We used a systems genetics approach to identify single nucleotide polymorphisms (SNPs) associated with lung function that act as eQTLs and change the level of expression of their target genes in lung tissue; termed eSNPs.

METHODS

The SpiroMeta-CHARGE GWAS results were integrated with lung eQTLs to map eSNPs and the genes and pathways underlying the associations in lung tissue. For comparison, a similar analysis was done in peripheral blood. The lung mRNA expression levels of the eSNP-regulated genes were tested for associations with lung function measures in 727 individuals. Additional analyses identified the pleiotropic effects of eSNPs from the published GWAS catalogue, and mapped enrichment in regulatory regions from the ENCODE project. Finally, the Connectivity Map database was used to identify potential therapeutics in silico that could reverse the COPD lung tissue gene signature.

FINDINGS

SNPs associated with lung function measures were more likely to be eQTLs and vice versa. The integration mapped the specific genes underlying the GWAS signals in lung tissue. The eSNP-regulated genes were enriched for developmental and inflammatory pathways; by comparison, SNPs associated with lung function that were eQTLs in blood, but not in lung, were only involved in inflammatory pathways. Lung function eSNPs were enriched for regulatory elements and were over-represented among genes showing differential expression during fetal lung development. An mRNA gene expression signature for COPD was identified in lung tissue and compared with the Connectivity Map. This in-silico drug repurposing approach suggested several compounds that reverse the COPD gene expression signature, including a nicotine receptor antagonist. These findings represent novel therapeutic pathways for COPD.

INTERPRETATION

The system genetics approach identified lung tissue genes driving the variation in lung function and susceptibility to COPD. The identification of these genes and the pathways in which they are enriched is essential to understand the pathophysiology of airway obstruction and to identify novel therapeutic targets and biomarkers for COPD, including drugs that reverse the COPD gene signature in silico.

FUNDING

The research reported in this article was not specifically funded by any agency. See Acknowledgments for a full list of funders of the lung eQTL study and the Spiro-Meta CHARGE GWAS.

NOTCH, ASCL1, p53 and RB alterations define an alternative pathway driving neuroendocrine and small cell lung carcinomas

Small cell lung cancers (SCLCs) and extrapulmonary small cell cancers (SCCs) are very aggressive tumors arising de novo as primary small cell cancer with characteristic genetic lesions in RB1 and TP53. Based on murine models, neuroendocrine stem cells of the terminal bronchioli have been postulated as the cellular origin of primary SCLC. However, both in lung and many other organs, combined small cell/non‐small cell tumors and secondary transitions from non‐small cell carcinomas upon cancer therapy to neuroendocrine and small cell tumors occur. We define features of “small cell‐ness” based on neuroendocrine markers, characteristic RB1 and TP53 mutations and small cell morphology. Furthermore, here we identify a pathway driving the pathogenesis of secondary SCLC involving inactivating NOTCH mutations, activation of the NOTCH target ASCL1 and canonical WNT‐signaling in the context of mutual bi‐allelic RB1 and TP53 lesions. Additionaly, we explored ASCL1 dependent RB inactivation by phosphorylation, which is reversible by CDK5 inhibition. We experimentally verify the NOTCH‐ASCL1‐RB‐p53 signaling axis in vitro and validate its activation by genetic alterations in vivo. We analyzed clinical tumor samples including SCLC, SCC and pulmonary large cell neuroendocrine carcinomas and adenocarcinomas using amplicon‐based Next Generation Sequencing, immunohistochemistry and fluorescence in situ hybridization. In conclusion, we identified a novel pathway underlying rare secondary SCLC which may drive small cell carcinomas in organs other than lung, as well.

What's new?

Using next generation sequencing and establishing features of ‘small cell‐ness’, we identified a NOTCH‐ASCL1‐RB1‐TP53 signaling axis driving small cell cancers. In contrast to the previously described bi‐allelic RB1/TP53 loss in neuroendocrine stem cells as origin of primary small cell neuroendocrine cancers, the NOTCH‐ASCL1 mediated signaling defines an alternative pathway driving secondary small cell neuroendocrine cancers arising from non‐small cell cancers. Moreover, we show a preclinical rational for therapeutically testing WNT‐inhibitors in small cell cancers.

Stem cell and progenitor fate in the mammalian intestine: Notch and lateral inhibition in homeostasis and disease

The control of cell fate decisions is vital to build functional organs and maintain normal tissue homeostasis, and many pathways and processes cooperate to direct cells to an appropriate final identity. Because of its continuously renewing state and its carefully organised hierarchy, the mammalian intestine has become a powerful model to dissect these pathways in health and disease. One of the signalling pathways that is key to maintaining the balance between proliferation and differentiation in the intestinal epithelium is the Notch pathway, most famous for specifying distinct cell fates in adjacent cells via the evolutionarily conserved process of lateral inhibition. Here, we will review recent discoveries that advance our understanding of how cell fate in the mammalian intestine is decided by Notch and lateral inhibition, focusing on the molecular determinants that regulate protein turnover, transcriptional control and epigenetic regulation.

Dll4/Notch1 signaling from tip/stalk endothelial cell specification to stroma-dependent lung tumor inhibition: a flavor of Dll4/Notch1 pleiotropy in tumor cell biology

Non-small cell lung cancer (NSCLC) still represents the leading cause of cancer death. Treating this disease with systemic chemotherapy has reached a plateau in effectiveness and is rather toxic to the patients, while molecularly targeted therapies against Epidermal Growth Factor Receptor can lead to resistance. On the other hand, therapies based on tumor angiogenesis inhibition have been recently proposed. Here we will discuss on the pleiotropy of the Dll4/Notch1 cell-to-cell signaling in NSCLC, as alternative target for future therapeutic approaches.

Notch signaling: a hero or villain in the war against cancer?

The Notch signal transduction pathway regulates cell fate decisions throughout embryonic development. The mechanisms through which Notch signaling maintains cellular integrity are well understood. However, Notch signaling is more complex than previously thought as Notch is also involved in cancer where it functions as both an oncogene and tumor suppressor depending on the cellular context. Aberrant activation of oncogenic Notch is found in various cancers prompting the search for therapeutic agents to attenuate constitutively active Notch. However, there is also substantial evidence that Notch signaling suppresses tumor growth and progression, suggesting that Notch activators might be of therapeutic benefit in other cancers. This editorial describes the dual role of Notch signaling observed within and across multiple cancers. We highlight a study in non-small cell lung cancer cells (NSCLC) revealing a tumor suppressive role for endothelial cell Dll4-activated Notch1 and the underlying molecular mechanism involving suppression of PI3K signaling.

Secreted phosphoprotein 1 is a determinant of lung function development in mice

Secreted phosphoprotein 1 (Spp1) is located within quantitative trait loci associated with lung function that was previously identified by contrasting C3H/HeJ and JF1/Msf mouse strains that have extremely divergent lung function. JF1/Msf mice with diminished lung function had reduced lung SPP1 transcript and protein during the peak stage of alveologenesis (postnatal day [P]14-P28) as compared with C3H/HeJ mice. In addition to a previously identified genetic variant that altered runt-related transcription factor 2 (RUNX2) binding in the Spp1 promoter, we identified another promoter variant in a putative RUNX2 binding site that increased the DNA protein binding. SPP1 induced dose-dependent mouse lung epithelial-15 cell proliferation. Spp1((-/-)) mice have decreased specific total lung capacity/body weight, higher specific compliance, and increased mean airspace chord length (Lm) compared with Spp1((+/+)) mice. Microarray analysis revealed enriched gene ontogeny categories, with numerous genes associated with lung development and/or respiratory disease. Insulin-like growth factor 1, Hedgehog-interacting protein, wingless-related mouse mammary tumor virus integration site 5A, and NOTCH1 transcripts decreased in the lung of P14 Spp1((-/-)) mice as determined by quantitative RT-PCR analysis. SPP1 promotes pneumocyte growth, and mice lacking SPP1 have smaller, more compliant lungs with enlarged airspace (i.e., increased Lm). Microarray analysis suggests a dysregulation of key lung developmental transcripts in gene-targeted Spp1((-/-)) mice, particularly during the peak phase of alveologenesis. In addition to its known roles in lung disease, this study supports SPP1 as a determinant of lung development in mice.

Lung cancer stem cells: Molecular features and therapeutic targets

Lung cancers are highly heterogeneous and resistant to available therapeutic agents, with a five year survival rate of less than 15%. Despite significant advances in our knowledge of the genetic alterations and aberrations in signaling pathways, it has been difficult to determine the basis of lung cancer heterogeneity and drug resistance. Cancer stem cell model has attracted a significant amount of attention in recent years as a viable explanation for the heterogeneity, drug resistance, dormancy and recurrence and metastasis of various tumors. At the same time, cancer stem cells have been relatively less characterized in lung cancers. This review summarizes the current understanding of lung cancer stem cells, including their molecular features and signaling pathways that drive their stemness. This review also discusses the potential startegies to inhibit the signaling pathways driving stemness, in an effort to eradicate these cells to combat lung cancer.

Molecular pathways and therapeutic targets in lung cancer

Lung cancer is still the leading cause of cancer death worldwide. Both histologically and molecularly lung cancer is heterogeneous. This review summarizes the current knowledge of the pathways involved in the various types of lung cancer with an emphasis on the clinical implications of the increasing number of actionable molecular targets. It describes the major pathways and molecular alterations implicated in the development and progression of non-small cell lung cancer (adenocarcinoma and squamous cancer), and of small cell carcinoma, emphasizing the molecular alterations comprising the specific blueprints in each group. The approved and investigational targeted therapies as well as the immune therapies, and clinical trials exploring the variety of targeted approaches to treatment of lung cancer are the main focus of this review.

HES1 is a master regulator of glucocorticoid receptor-dependent gene expression

Hairy and enhancer of split-1 (HES1) is a basic helix-loop-helix transcription factor that is a key regulator of development and organogenesis. However, little is known about the role of HES1 after birth. Glucocorticoids, primary stress hormones that are essential for life, regulate numerous homeostatic processes that permit vertebrates to cope with physiological challenges. The molecular actions of glucocorticoids are mediated by glucocorticoid receptor-dependent regulation of nearly 25% of the genome. Here, we established a genome-wide molecular link between HES1 and glucocorticoid receptors that controls the ability of cells and animals to respond to stress. Glucocorticoid signaling rapidly and robustly silenced HES1 expression. This glucocorticoid-dependent repression of HES1 was necessary for the glucocorticoid receptor to regulate many of its target genes. Mice with conditional knockout of HES1 in the liver exhibited an expanded glucocorticoid receptor signaling profile and aberrant metabolic phenotype. Our results indicate that HES1 acts as a master repressor, the silencing of which is required for proper glucocorticoid signaling.

Targeting notch signaling pathway in cancer: clinical development advances and challenges

Notch signaling plays an important role in development and cell fate determination, and it is deregulated in human hematologic malignancies and solid tumors. This review includes a brief introduction of the relevant pathophysiology of Notch signaling pathway and primarily focuses on the clinical development of promising agents that either obstruct Notch receptor cleavages such as γ-secretase inhibitors (GSIs) or interfere with the Notch ligand-receptor interaction by monoclonal antibodies (mAbs). Antitumor activity by GSIs and mAbs administered as single agent in early phases of clinical trials has been observed in advanced or metastatic thyroid cancer, non-small cell lung cancer, intracranial tumors, sarcoma or desmoid tumors, colorectal cancer with neuroendocrine features, melanoma and ovarian cancer. A number of mechanism-based adverse events particularly gastrointestinal toxicities emerged and mitigation strategies are developed after testing multiple GSIs and Notch targeting mAbs. We also discuss pharmacodynamic biomarkers in conjunction with methods of assessment of the molecular target inhibition validation. Biomarkers of efficacy or benefit may be of importance for a successful development of this class of drugs.

Effect of mesenchymal stem cells and a novel curcumin derivative on Notch1 signaling in hepatoma cell line

This study was conducted to evaluate the effect of mesenchymal stem cells (MSCs) and a novel curcumin derivative (NCD) on HepG2 cells (hepatoma cell line) and to investigate their effect on Notch1 signaling pathway target genes. HepG2 cells were divided into HepG2 control group, HepG2 cells treated with MSC conditioned medium (MSCs CM), HepG2 cells treated with a NCD, HepG2 cells treated with MSCs CM and NCD, and HepG2 cells treated with MSCs CM (CM of MSCs pretreated with a NCD). Expression of Notch1, Hes1, VEGF, and cyclin D1 was assessed by real-time, reverse transcription-polymerase chain reaction (RT-PCR) in HepG2 cells. In addition, HepG2 proliferation assay was performed in all groups. Notch1 and its target genes (Hes1 and cyclin D1) were downregulated in all treated groups with more suppressive effect in the groups treated with both MSCs and NCD. Also, treated HepG2 cells showed significant decrease in cell proliferation rate. These data suggest that modulation of Notch1 signaling pathway by MSCs and/or NCD can be considered as a therapeutic target in HCC.

Cancer stem cells in lung cancer: Evidence and controversies

The cancer stem cell (CSC) model is based on a myriad of experimental and clinical observations suggesting that the malignant phenotype is sustained by a subset of cells characterized by the capacity for self-renewal, differentiation and innate resistance to chemotherapy and radiation. CSC may be responsible for disease recurrence after definitive therapy and may therefore be functionally synonymous with minimal residual disease. Similar to other solid tumours, several putative surface markers for lung CSC have been identified, including CD133 and CD44. In addition, expression and/or activity of the cytoplasmic enzyme aldehyde dehydrogenase ALDH and capacity of cells to exclude membrane permeable dyes (known as the 'side population') correlate with stem-like function in vitro and in vivo. Embryonic stem cell pathways such as Hedgehog, Notch and WNT may also be active in lung cancers stem cells and therefore may be therapeutically targetable for maintenance therapy in patients achieving a complete response to surgery, radiotherapy or chemotherapy. This paper will review the evidence regarding the existence and function of lung CSC in the context of the experimental and clinical evidence and discuss some ongoing controversies regarding this model.

Inhibition of ADAM-17 more effectively down-regulates the Notch pathway than that of γ-secretase in renal carcinoma

BACKGROUND

Our study is to research the effect of inhibited ADAM-17 expression through the Notch pathway in renal carcinoma.

METHODS

Immunohistochemistry and western blot were used to examine the expression of ADAM-17 protein in renal cancer tissues. Proliferation and cell invasion of 786-o cells, as well as OS-RC-2 cells, after treatment with two different inhibitors of the Notch pathway, were examined by CCK-8 assay and Transwell assay, respectively. 786-o cell apoptosis was measured using the FCM test.

RESULTS

ADAM-17 was highly expressed in RCC tissues. Compared with blocking γ-secretase, a known mechanism of impairing Notch, blockade of ADAM-17 more effectively down-regulated the expressions of Notch1 and HES-1 proteins. Similarly, we found that the ADAM-17 inhibitor, Marimastat, could more efficiently reduce renal cell proliferation and invasive capacity in comparison with the γ-secretase inhibitor DAPT when used at the same dose. Similar results were obtained when apoptosis of 786-o was measured.

CONCLUSION

Compared with γ-secretase, inhibition of ADAM-17 expression more effectively inhibits Notch pathway-mediated renal cancer cell proliferation and invasion. ADAM-17 may be a new target for future treatment of renal carcinoma.