Genetic and epigenetic changes in lung carcinoma and their clinical implications

Impact of Electronic Cigarettes, Heated Tobacco Products and Conventional Cigarettes on the Generation of Oxidative Stress and Genetic and Epigenetic Lesions in Human Bronchial Epithelial BEAS-2B Cells

Electronic cigarettes (e-cig) and heated tobacco products (HTP) are often used as smoking cessation aids, while the harm reduction effects of these alternatives to cigarettes are still the subject of controversial debate, in particular regarding their carcinogenic potential. The objective of this study is to compare the effects of e-cig, HTP and conventional cigarette emissions on the generation of oxidative stress and genetic and epigenetic lesions in human bronchial epithelial BEAS-2B cells. Our results show that HTP were less cytotoxic than conventional cigarettes while e-cig were not substantially cytotoxic in BEAS-2B cells. E-cig had no significant effect on the Nrf2 pathway, whereas HTP and cigarettes increased the binding activity of Nrf2 to antioxidant response elements and the expression of its downstream targets HMOX1 and NQO1. Concordantly, only HTP and cigarettes induced oxidative DNA damage and significantly increased DNA strand breaks and chromosomal aberrations. Neither histone modulations nor global DNA methylation changes were found after acute exposure, regardless of the type of emissions. In conclusion, this study reveals that HTP, unlike e-cig, elicit a biological response very similar to that of cigarettes, but only after a more intensive exposure: both tobacco products induce cytotoxicity, Nrf2-dependent oxidative stress and genetic lesions in human epithelial pulmonary cells. Therefore, the health risk of HTP should not be underestimated and animal studies are required in order to determine the tumorigenic potential of these emerging products.

miRNAs: Potential as Biomarkers and Therapeutic Targets for Cancer

MicroRNAs (miRNAs) are single-stranded, non-coding RNA molecules that regulate gene expression post-transcriptionally by binding to messenger RNAs. miRNAs are important regulators of gene expression, and their dysregulation is implicated in many human and canine diseases. Most cancers tested to date have been shown to express altered miRNA levels, which indicates their potential importance in the oncogenic process. Based on this evidence, numerous miRNAs have been suggested as potential cancer biomarkers for both diagnosis and prognosis. miRNA-based therapies have also been tested in different cancers and have provided measurable clinical benefits to patients. In addition, understanding miRNA biogenesis and regulatory mechanisms in cancer can provide important knowledge about resistance to chemotherapies, leading to more personalized cancer treatment. In this review, we comprehensively summarized the importance of miRNA in human and canine cancer research. We discussed the current state of development and potential for the miRNA as both a diagnostic marker and a therapeutic target.

The role of statins in lung cancer

Lung cancer is one of the most common causes of cancer-related mortality in the 21^st century. Statins as inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase not only reduce the cholesterol levels in the blood and decrease the risk of cardiovascular disease but may also play an important role in the prevention and treatment of lung cancer. Statins have several antitumor properties including the ability to reduce cell proliferation and angiogenesis, decrease invasion and synergistic suppression of lung cancer progression. Statins induce tumor cell apoptosis by inhibition of downstream products such as small GTP-binding proteins, Rho, Ras and Rac, which are dependent on isoprenylation. Statins reduce angiogenesis in tumors by down-regulation of pro-angiogenic factors, such as vascular endothelial growth factor. In this review, the feasibility and efficacy of statins in the prevention and treatment of lung cancer are discussed.

Liquid biopsy uncovers distinct patterns of DNA methylation and copy number changes in NSCLC patients with different EGFR-TKI resistant mutations

Targeted therapy with tyrosine kinase inhibitors (TKI) provides survival benefits to a majority of patients with non-small cell lung cancer (NSCLC). However, resistance to TKI almost always develops after treatment. Although genetic and epigenetic alterations have each been shown to drive resistance to TKI in cell line models, clinical evidence for their contribution in the acquisition of resistance remains limited. Here, we employed liquid biopsy for simultaneous analysis of genetic and epigenetic changes in 122 Vietnamese NSCLC patients undergoing TKI therapy and displaying acquired resistance. We detected multiple profiles of resistance mutations in 51 patients (41.8%). Of those, genetic alterations in EGFR, particularly EGFR amplification (n = 6), showed pronounced genome instability and genome-wide hypomethylation. Interestingly, the level of hypomethylation was associated with the duration of response to TKI treatment. We also detected hypermethylation in regulatory regions of Homeobox genes which are known to be involved in tumor differentiation. In contrast, such changes were not observed in cases with MET (n = 4) and HER2 (n = 4) amplification. Thus, our study showed that liquid biopsy could provide important insights into the heterogeneity of TKI resistance mechanisms in NSCLC patients, providing essential information for prediction of resistance and selection of subsequent treatment.

Serum Folate Levels and Lung Cancer Risk: A Meta- Epidemiological Study of Population-based Case-Control Studies

OBJECTIVE

While it has been claimed that lung cancer occurs due to epigenetic mechanisms, four systematic reviews were reported to investigate the association between serum folate levels and lung cancer risk. Considering some methodological problems founded in the systematic review, a meta-epidemiological study was conducted.

METHODS

The selection criteria of this study were defined that a case-control study was conducted to determine the risk of lung cancer occurrence according to the concentration of serum folate and its results showed odds ratio and its 95% confidence interval. Additional paper was explored from cited lists of 4 papers selected by previous systematic reviews. Random effect model was applied if I-squared value was over 50%.

RESULTS

For 5 case-control studies selected, the summary odds ratios (and their 95% confidence intervals) were 0.82 (0.74-0.90) in men, 0.70 (0.62-0.79) in former smokers, and 0.86 (0.75-1.00) in non-smokers.

CONCLUSION

Higher foliate levels can decrease lung cancer risk in men and former smokers. Especially, the protective effect was highest in former smokers compared in non-smokers and current smokers. Based on these facts, folate fortification programs to reduce lung cancer risk would be focused on former smokers in men. And some epidemiological studies are needed to provide a hypothesis to explain the sex differences in the association between folate and lung cancer risk.

Single-sample landscape entropy reveals the imminent phase transition during disease progression

Motivation

The time evolution or dynamic change of many biological systems during disease progression is not always smooth but occasionally abrupt, that is, there is a tipping point during such a process at which the system state shifts from the normal state to a disease state. It is challenging to predict such disease state with the measured omics data, in particular when only a single sample is available.

Results

In this study, we developed a novel approach, i.e. single-sample landscape entropy (SLE) method, to identify the tipping point during disease progression with only one sample data. Specifically, by evaluating the disorder of a network projected from a single-sample data, SLE effectively characterizes the criticality of this single sample network in terms of network entropy, thereby capturing not only the signals of the impending transition but also its leading network, i.e. dynamic network biomarkers. Using this method, we can characterize sample-specific state during disease progression and thus achieve the disease prediction of each individual by only one sample. Our method was validated by successfully identifying the tipping points just before the serious disease symptoms from four real datasets of individuals or subjects, including influenza virus infection, lung cancer metastasis, prostate cancer and acute lung injury.

Availability and implementation

https://github.com/rabbitpei/SLE.

Supplementary information

Supplementary data are available at Bioinformatics online.

Identification of key biomarkers and potential molecular mechanisms in lung cancer by bioinformatics analysis

Lung cancer is one of the most widespread neoplasms worldwide. To identify the key biomarkers in its carcinogenesis and development, the mRNA microarray datasets GSE102287, GSE89047, GSE67061 and GSE74706 were obtained from the Gene Expression Omnibus database. GEO2R was used to identify the differentially expressed genes (DEGs) in lung cancer. The Database for Annotation, Visualization and Integrated Discovery was used to analyze the functions and pathways of the DEGs, while the Search Tool for the Retrieval of Interacting Genes/Proteins and Cytoscape were used to obtain the protein-protein interaction (PPI) network. Kaplan Meier curves were used to analyze the effect of the hub genes on overall survival (OS). Module analysis was completed using Molecular Complex Detection in Cytoscape, and one co-expression network of these significant genes was obtained with cBioPortal. A total of 552 DEGs were identified among the four microarray datasets, which were mainly enriched in 'cell proliferation', 'cell growth', 'cell division', 'angiogenesis' and 'mitotic nuclear division'. A PPI network, composed of 44 nodes and 886 edges, was constructed, and its significant module had 16 hub genes in the whole network: Opa interacting protein 5, exonuclease 1, PCNA clamp-associated factor, checkpoint kinase 1, hyaluronan-mediated motility receptor, maternal embryonic leucine zipper kinase, non-SMC condensin I complex subunit G, centromere protein F, BUB1 mitotic checkpoint serine/threonine kinase, cyclin A2, thyroid hormone receptor interactor 13, TPX2 microtubule nucleation factor, nucleolar and spindle associated protein 1, kinesin family member 20A, aurora kinase A and centrosomal protein 55. Survival analysis of these hub genes revealed that they were markedly associated with poor OS in patients with lung cancer. In summary, the hub genes and DEGs delineated in the research may aid the identification of potential targets for diagnostic and therapeutic strategies in lung cancer.

Synergistic Effect of Novel EGFR Inhibitor AZD8931 and p38α siRNA in Lung Adenocarcinoma Cancer Cells

Background:

Lung cancer is the leading cause of cancer-related death with less than 5-year survival rate for both men and women worldwide. EGFR and MAPK signaling pathways have a critical role in proliferation and progression of various cancers, including lung cancer. P38 map kinase plays different role in various tissue hence showing a tissue-dependent behavior. It acts as an oncogene in some tissues while plays as tumor suppressor in some other tissues. The aim of this study was to investigate the combined effect of P38 αspecific siRNA and EGFR inhibitor on apoptosis and proliferation of A549 lung cancer cell line.

Objective:

This article is dedicated to the synergistic effect of novel EGFR inhibitor AZD8931 and P38 α siRNA in lung adenocarcinoma cancer cells proliferation and apoptosis.

Methods and Materials:

The A549 lung cancer cells were treated with P38 α- siRNA and EGFR inhibitor alone or in combination. The cytotoxic effects of P38 α- siRNA and EGFR inhibitor were determined using MTT assay. Relative P38 α and EGFR mRNA levels were measured by QRT-PCR. Induction of apoptosis were measured by FACS analysis.

Results:

The expression of mRNA related to P38 α, EGFR, and Her2 genes was reduced to 23.4%, 52.4%, and 75, respectively, after treatment of their inhibitors. Also, MTT assay showed that the cell viability after treatment with p38 α SiRNA, EGFR inhibitor and their combination was reduced to 51.02%, 48.9%, and 25.11%, respectively. FACS results indicated that p38 α siRNA, EGFR inhibitor and their combination, reduced the population of live cells to 49.5%, 32.2% and 14.3% in comparison to the population of untreated control cells (99.5%).

Conclusion:

The results of this study indicated that p38 α and EGFR might play an important role in the development and growth of lung cancer and might be a potential therapeutic target for the treatment of lung cancer.

Targeted Therapies in Veterinary Oncology

Advances in molecular biology have permitted a much more detailed understanding of cellular dysfunction at the molecular and genetic levels in cancer cells. This has resulted in the identification of novel targets for therapeutic intervention, including proteins that regulate signal transduction, gene expression, and protein turnover. In many instances, small molecules are used to disrupt the function of these targets, often through competitive inhibition of ATP binding or the prevention of necessary protein-protein interactions. More than 40 small molecule inhibitors are now approved to treat a variety of human cancers, substantially impacting patient outcomes.

Targeting the KRAS, p38α, and NF-κB in lung adenocarcinoma cancer cells: The effect of combining RNA interferences with a chemical inhibitor

BACKGROUND

Lung cancer is the leading cause of cancer-related death with less than 5-year survival rate for both men and women worldwide. KRAS (Kirsten rat sarcoma), nuclear factor-κB (NF-κB), and mitogen-activated protein kinase (MAPK) signaling pathways have a critical role in the proliferation and progression of various cancers, including lung cancer. The p38 MAPK plays a different role in various tissue hence show a tissue-dependent behavior. It acts as an oncogene in some tissues while plays as a tumor suppressor in some other tissues. Also, KRAS and NF-κB act as an oncogene in various cancer. This study was dedicated to analyzing the combined effect of NF-κB inhibitor, specific KRAS, and p38α small interfering RNA (siRNA) in A549 cell line.

MATERIALS AND METHODS

The cytotoxic effects of p38α siRNA, KRAS siRNA, and NF-κB inhibitor were determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide (MTT) assay. Relative p38α, KRAS, and NF-κB messenger RNA (mRNA) levels were measured by quantitative reverse-transcription polymerase chain reaction. Induction of apoptosis by treatments was measured by fluorescence-activated cell sorting (FACS) analysis.

RESULTS

The expression of mRNA related to p38α and KRAS genes was reduced to 23.4% and 26.7%, respectively, after treatment with specific siRNAs. Also, MTT assay showed that the cell viability after treatment with p38α siRNA, KRAS siRNA, NF-κB inhibitor and their combination was reduced. FACS results indicated that p38α siRNA, KRAS siRNA, and NF-κB inhibitor, and their combination, reduced the population of live cells in comparison with the population of untreated control cells (99.5%). The results are expressed as mean ± SD (n = 3); *P < 0.05; ** P < 0.01; *** P < 0.001; **** P < 0.0001 vs control group.

CONCLUSION

The results of this study indicated that p38α, KRAS, and NF-κB signaling pathways might play an important role in the development and growth of lung cancer and might be a potential therapeutic target for treatment of lung cancer.

Multifunctional nanoparticles co-delivering EZH2 siRNA and etoposide for synergistic therapy of orthotopic non-small-cell lung tumor

Malignant proliferation and metastasis in non-small cell lung carcinoma (NSCLC) are great challenges for effective clinical treatment through conventional chemotherapy. The combinational therapy strategy of RNA interfering (RNAi) technology and chemotherapeutic agents have been reported to be promising for effective cancer therapy. In this study, based on multifunctional nanoparticles (NPs), the simultaneous delivery of etoposide (ETP) and anti-Enhancer of Zeste Homologue 2 (EZH2) siRNA for the effective treatment of orthotopic lung tumor was achieved. The NPs exhibited pH/redox dual sensitivity verified by particle size changes, morphological changes, and in vitro release of drugs. Confocal microscopy analysis confirmed that the NPs exhibited endosomal escape property and on-demand intracellular drug release behavior, which can protect siRNA from degradation and facilitate the chemotherapeutic effect respectively. In vitro tumor cell motility study demonstrated that EZH2 siRNA loaded in NPs can decrease the migration and invasion capabilities of tumor cells by downregulating the expression of EZH2 mRNA and protein. In particular, an antiproliferation study revealed that the co-delivery of siRNA and ETP in the multifunctional NPs can induce a synergistic therapeutic effect on NSCLC. In vivo targeting evaluation showed that cRGDyC-PEG modification on NPs exhibited a low distribution in normal organs and an obvious accumulation in orthotopic lung tumor. Furthermore, targeted NPs co-delivering siRNA and ETP showed superior inhibition on tumor growth and metastasis and produced minimal systemic toxicity. These findings indicated that multifunctional NPs can be utilized as a co-delivery system, and that the combination of EZH2 siRNA and ETP can effectively treat NSCLC.

The low expression of miR-451 predicts a worse prognosis in non-small cell lung cancer cases

PURPOSE

miR-451 is a tumor suppressive microRNA with several target genes, including Macrophage migration inhibitory factor (MIF). As little is known about the expression and clinicopathological significance of mir-451 in NSCLC, we performed a clinicopathological study of 370 NSCLC cases to clarify them. Cell biological experiments were also performed on NSCLC cell lines to confirm the tumor-suppressive role of miR-451 and whether or not MIF is targeted by miR-451.

METHODS

We analyzed 370 NSCLC cases for the miR-451 expression by quantitative real-time polymerase chain reaction and the MIF expression by immunohistochemistry. Eighty-four background lung tissue samples were also evaluated for the miR-451 expression. The clinicopathological and genetic factors surveyed were the disease-free survival, smoking status, histological type, disease stage, EGFR gene mutations and ALK rearrangements. In 286 adenocarcinoma cases, the invasive status (adenocarcinoma in situ, minimally invasive adenocarcinoma and invasive adenocarcinoma) was also evaluated. Five NSCLC cell lines (H23, H441, H522, H1703, and H1975) were cultured and evaluated for their miR-451 and MIF expression. The cell lines with lower miR-451 and higher MIF expressions were then selected and transfected with miR-451-mimic to observe its effects on MIF expression, Akt and Erk status, cell proliferation, and cell migration.

RESULTS

The miR-451 expression was down-regulated in cancer tissues compared with background lung tissues (P<0.0001). Factors such as advanced disease stage, positive pleural invasion and nodal status and being a smoker were significantly correlated with a lower expression of miR-451 (P<0.05 each), while EGFR gene mutations and ALK rearrangements were not. In adenocarcinoma, invasive and minimally invasive adenocarcinoma showed lower expression of miR-451 than adenocarcinoma in situ (P<0.0005, respectively). A survival analysis showed that a lower expression of miR-451 was an independent predictor of a poor prognosis for NSCLC (P<0.05). The MIF expression was inversely correlated with the miR-451 expression. Out of 5 NSCLC cell lines examined, H441 and H1975 showed higher MIF and lower miR-451 expressions. After the transfection of miR-451-mimic, the MIF expression and phosphorylated Akt expression of these cell lines was suppressed, as were cell proliferation and cell migration.

CONCLUSION

This clinicopathological study of 370 NSCLC cases and the cell biological studies of NSCLC cell lines clarified the tumor-suppressive role of miR-451 and its prognostic value. We also validated MIF as a target of miR-451 in NSCLC.

Reaching the limits of prognostication in non-small cell lung cancer: an optimized biomarker panel fails to outperform clinical parameters

Numerous protein biomarkers have been analyzed to improve prognostication in non-small cell lung cancer, but have not yet demonstrated sufficient value to be introduced into clinical practice. Here, we aimed to develop and validate a prognostic model for surgically resected non-small cell lung cancer. A biomarker panel was selected based on (1) prognostic association in published literature, (2) prognostic association in gene expression data sets, (3) availability of reliable antibodies, and (4) representation of diverse biological processes. The five selected proteins (MKI67, EZH2, SLC2A1, CADM1, and NKX2-1 alias TTF1) were analyzed by immunohistochemistry on tissue microarrays including tissue from 326 non-small cell lung cancer patients. One score was obtained for each tumor and each protein. The scores were combined, with or without the inclusion of clinical parameters, and the best prognostic model was defined according to the corresponding concordance index (C-index). The best-performing model was subsequently validated in an independent cohort consisting of tissue from 345 non-small cell lung cancer patients. The model based only on protein expression did not perform better compared to clinicopathological parameters, whereas combining protein expression with clinicopathological data resulted in a slightly better prognostic performance (C-index: all non-small cell lung cancer 0.63 vs 0.64; adenocarcinoma: 0.66 vs 0.70, squamous cell carcinoma: 0.57 vs 0.56). However, this modest effect did not translate into a significantly improved accuracy of survival prediction. The combination of a prognostic biomarker panel with clinicopathological parameters did not improve survival prediction in non-small cell lung cancer, questioning the potential of immunohistochemistry-based assessment of protein biomarkers for prognostication in clinical practice.

LINE-1 hypomethylation is associated to specific clinico-pathological features in Stage I non-small cell lung cancer

OBJECTIVES

We hypothesize that selected genetic and/or epigenetic changes associated with advanced tumours may help identifying early non-small cell lung cancers (NSCLCs) that recur after resection. Among epigenetic changes, long interspersed nuclear element-1 (LINE-1) hypomethylation is seen early during carcinogenesis and may act in concert with genetic alterations to cancer progression. LINE-1 hypomethylation and gene mutations frequently involved in lung cancer, were analysed to evaluate their prognostic role in resected stage I NSCLC.

METHODS

Gene mutations and LINE-1 methylation were analysed in 167 Caucasian patients with stage I NSCLC, namely 100 adenocarcinomas (ADC) and 67 squamous-cell carcinomas (SqCC), using mass-spectrometry and pyrosequencing. We evaluated the correlation between molecular results and clinico-pathological data: age, gender, smoking status, period of surgery, histology, grading, pathological stage, p53 expression, LINE-1 hypomethylation. These variables have been assessed as possible predictors of cancer related survival by regression analysis.

RESULTS

Frequency and spectrum of gene mutations were significantly different in ADCs compared with SqCCs. p53 positivity was more common in SqCC, while EGFR or KRAS mutations were mainly detected in ADC. LINE1 hypomethylation was associated with SqCC histology, p53 immunoreactivity and smoking habit. Stage IB, LINE-1 hypomethylation and PIK3CA mutation independently predicted a worse cancer-related survival. When combined into a scoring system, their prognostic power was strengthened.

CONCLUSIONS

In many stage I NSCLC a mutation pattern of advanced disease was observed. Stage IB, LINE-1 hypomethylation and PIK3CA mutation were associated to poor prognosis. Genetic and epigenetic events occurring in early carcinogenesis may help identifying stage I NSCLC patients who deserve adjuvant therapy.

MIIP accelerates epidermal growth factor receptor protein turnover and attenuates proliferation in non-small cell lung cancer

The migration and invasion inhibitory protein (MIIP) has been discovered recently to have inhibitory functions in cell proliferation and migration. Overexpression of MIIP reduced the intracellular steady-state level of epidermal growth factor receptor (EGFR) protein in lung cancer cells with no effect on EGFR mRNA expression compared to that in the control cells. This MIIP-promoted EGFR protein degradation was reversed by proteasome and lysosome inhibitors, suggesting the involvement of both proteasomal and lysosomal pathways in this degradation. This finding was further validated by pulse-chase experiments using ³⁵S-methionine metabolic labeling. We found that MIIP accelerates EGFR protein turnover via proteasomal degradation in the endoplasmic reticulum and then via the lysosomal pathway after its entry into endocytic trafficking. MIIP-stimulated downregulation of EGFR inhibits downstream activation of Ras and blocks the MEK signal transduction pathway, resulting in inhibition of cell proliferation. The negative correlation between MIIP and EGFR protein expression was validated in lung adenocarcinoma samples. Furthermore, the higher MIIP protein expression predicts a better overall survival of Stage IA-IIIA lung adenocarcinoma patients who underwent radical surgery. These findings reveal a new mechanism by which MIIP inhibits cell proliferation.

Frequency of EGFR mutations in lung adenocarcinoma with malignant pleural effusion: Implication of cancer biological behaviour regulated by EGFR mutation

OBJECTIVE

A retrospective single-centre study to compare the clinical features of patients with lung adenocarcinoma with and without epidermal growth factor receptor (EGFR) mutations.

METHODS

Pretreatment medical records of patients with lung adenocarcinoma were reviewed. DNA was extracted from paraffin wax-embedded tumour tissue for analysis of EGFR mutations. Malignant pleural effusion (MPE) was diagnosed by cytopathological testing of pleural fluid.

RESULTS

EGFR mutations (19-Del and L858R) were recorded in 81/283 patients (28.6%). MPE was found in 42/283 patients (14.8%). In patients with stage IV disease, the frequency of EGFR mutations was higher in those with MPE than in those without MPE. EGFR mutations were independently associated with female sex, no history of smoking and presence of MPE.

CONCLUSIONS

There was a positive association between EGFR mutation and the presence of MPE. EGFR mutations may play an important role in the formation of MPE.

Body mass index and risk of lung cancer: Systematic review and dose-response meta-analysis

Questions remain about the significance of the dose-response relationship between body mass index (BMI) and lung cancer (LC) risk. Pertinent studies were identified through a search in EMBASE and PUBMED from July 2014 until March 2015. The summary relative risk (SRR) and confidence interval (CI) were estimated. The dose-response relationship was assessed using a restricted cubic spline. The overall meta-analysis showed evidence of a nonlinear association between BMI and LC risk (Pnonlinearity < 0.001). The SRR were 0.98 (95%CI: 0.95-1.01) for 25 kg/m(2), 0.91 (95%CI: 0.85-0.98) for 30 kg/m(2) and 0.81 (95% CI: 0.72-0.91) for 35 kg/m(2), with mild between-study heterogeneity (I(2) = 5%). The results of the stratified analysis by gender were comparable to those of the overall meta-analysis. When stratified by smoking status, linear dose-response associations were observed for current smokers, ex-smokers and non-smokers (Pnonlinearity > 0.05), whereas the effects were attenuated when restricting analysis to non-smokers, and at the point of 30 kg/m(2), the SRR was 0.96 (95%CI: 0.86-1.07) for males and 0.95 (95%CI: 0.89-1.02) for females. This meta-analysis provides quantitative evidence that increasing BMI is a protective factor against LC. Keeping normal-to-moderate BMI should be prescribed as an evidence-based lifestyle tip for LC prevention in smokers.

[Methylation Status of miR-182 Promoter in Lung Cancer Cell Lines]

背景与目的

已有的研究证明MiR-182的异常调控与恶性肿瘤的发生发展密切相关，本研究旨在探讨肺癌细胞中miR-182启动子的甲基化状态对miR-182表达的影响。

方法

荧光定量PCR检测肺癌细胞中miR-182表达水平，甲基化特异性PCR检测各细胞株中miR-182启动子区的甲基化状态，并通过测序进行验证。DNA甲基转移酶抑制剂5’-Aza-dC处理后检测各肺癌细胞株中miR-182表达变化。

结果

MiR-182在不同肺癌细胞株的表达水平不同，其中，在高转移性肺癌细胞株如A549和L9981中相对呈低表达；而在低转移性细胞株95C则相对呈高表达。MSP及测序分析显示多株肺癌细胞株中miR-182启动子区域存在DNA甲基化，其中A549细胞甲基化程度最高。在5'-氮杂-脱氧胞苷酸（5’-Aza-dC）作用下，A549细胞及其他肺癌细胞中miR-182表达水平均明显升高。

结论

在肺癌细胞中miR-182启动子区域存在异常甲基化，miR-182的表达受DNA甲基化的调控。MiR-182的甲基化在肺癌中的作用尚需进一步研究。

A prospective study of tumor suppressor gene methylation as a prognostic biomarker in surgically resected stage I to IIIA non-small-cell lung cancers

INTRODUCTION

While retrospective analyses support an association between early tumor recurrence and tumor suppressor gene promoter methylation in early-stage non-small-cell lung cancers (NSCLCs), few studies have investigated this question prospectively.

METHODS

Primary tumor tissue from patients with resected pathologic stage I to IIIA NSCLCs was collected at the time of surgery and analyzed for promoter methylation via methylation-specific reverse transcriptase polymerase chain reaction (MethyLight). The primary objective was to determine an association between promoter methylation of 10 individual tumor suppressor genes (CDKN2A, CDH13, RASSF1, APC, MGMT, GSTP1, DAPK1, WIF1, SOCS3, and ADAMTS8) and recurrence-free survival (RFS), with the secondary objectives of determining association with overall survival (OS), and relation to clinical or pathologic features.

RESULTS

A total of 107 patients had sufficient tumor tissue for successful promoter methylation analysis. Majority of patients were former/current smokers (88%) with lung adenocarcinoma (78%) and pathologic stage I disease (62%). Median follow-up was 4 years. When controlled for pathologic stage, promoter methylation of the individual genes CDKN2A, CDH13, RASSF1, APC, MGMT, GSTP1, DAPK1, WIF1, and ADAMTS8 was not associated with RFS. Promoter methylation of the same genes was not associated with OS except for DAPK1 which was associated with improved OS (p = 0.03). The total number of genes with methylated promoters did not correlate with RFS (p = 0.89) or OS (p = 0.55).

CONCLUSION

Contrary to data established by previous retrospective series, tumor suppressor gene promoter methylation (CDKN2A, CDH13, RASSF1, APC, MGMT, GSTP1, DAPK1, WIF1, and ADAMTS8) was not prognostic for early tumor recurrence in this prospective study of resected NSCLCs.

Anti-tumor effect of polysaccharides from Scutellaria barbata D. Don on the 95-D xenograft model via inhibition of the C-met pathway

Polysaccharides isolated from Scutellaria barbata (PSB) have been reported to have anti-tumor effects. To investigate the underlying mechanism, a highly invasive, metastatic and phospho-c-Met overexpression lung carcinoma cell, 95-D cell line was used. The results showed that in vitro, PSB not only could inhibit the proliferation of 95-D cell line (IC(50) = 35.2 μg/mL), but also down-regulated the expression of phospho-c-Met and its downstream signaling molecules including phospho-Erk and phospho-Akt. In vivo, PSB inhibited tumor growth in the 95-D subcutaneous xenograft model in a dose-dependent manner; after once-daily intraperitoneal injection for 3 weeks, tumor growth inhibition T/C ratio for 100 and 200 mg/kg treatments was 42.72% and 13.6%, respectively. In the end of the in vivo study, tumor tissues were harvested for further evaluation of the phosphorylation level of c-Met, AKT, and ERK. Ex vivo results demonstrated that the phosphorylation of c-Met and its downstream signaling molecules were also significantly inhibited by PSB. Immunohistochemistry analysis showed dose-dependent inhibition of tumor cell proliferation (Ki67) and reduction of microvessel density (CD31). In summary, the results indicated that PSB exerted anti-tumor growth activity on human lung cancer 95-D in vitro and in vivo by directly regulating the c-Met signaling pathway and the anti-tumor effects were mainly based on its anti-proliferation and anti-angiogenesis action.

Semi-synthesis and anti-lung cancer activity evaluation of aryl dihydrothiazol acyl podophyllotoxin ester derivatives

S12, the best anticancer agent among the 17 podophyllotoxin derivatives, showed a proliferative inhibition effect via inhibiting tubulin polymerization.

Epigenetic silencing of microRNA-373 to epithelial-mesenchymal transition in non-small cell lung cancer through IRAK2 and LAMP1 axes

The role of microRNAs (miRNAs) in carcinogenesis as tumor suppressors or oncogenes has been widely reported. Epigenetic change is one of the mechanisms of transcriptional silencing of miRNAs in cancer. To identify lung cancer-related miRNAs that are mediated by histone modification, we conducted microarray analysis in the Calu-6 non-small cell lung cancer (NSCLC) cell line after treatment with suberoylanilide hydroxamic acid (SAHA), a histone deacetylase (HDAC) inhibitor. The expression level of miR-373 was enhanced by SAHA treatment in this cell line by microarray and the following quantitative RT-PCR analyses. Treatment with another HDAC inhibitor, Trichostatin A, restored the levels of miR-373 expression in A549 and Calu-6 cells, while demethylation drug treatment did not. Importantly, miR-373 was found to be down-regulated in NSCLC tissues and cell lines. Transfection of miR-373 into A549 and Calu-6 cells attenuated cell proliferation, migration, and invasion and reduced the expression of mesenchymal markers. Additional microarray analysis of miR-373-transfected cells and computational predictions identified IRAK2 and LAMP1 as targets of miR-373. Knockdown of these two genes showed similar biological effects to those of miR-373 overexpression. In clinical samples, overexpression of IRAK2 correlated with decreased disease-free survival of patients with non-adenocarcinoma. In conclusion, we found that miR-373 is silenced by histone modification in lung cancer cells and identified its function as a tumor suppressor and negative regulator of the mesenchymal phenotype through downstream IRAK2 and LAMP1 target genes.

Anti-proliferative of physcion 8-O-β-glucopyranoside isolated from Rumex japonicus Houtt. on A549 cell lines via inducing apoptosis and cell cycle arrest

Background

Lung cancers are leading causes of cancer death, and Rumex japonicus has been traditionally used in folk medicine as anti-microorganic, anti-inflammatory and anti-tumor agents. This study was designed to investigate the anti-proliferative activity of physcion 8-O-β-glucopyranoside (PG) isolated from Rumex japonicus Houtt. on A549 cell lines.

Methods

In our present study, PG was isolated and identified from the ethanol extracts of R. japonicus. MTT method was used to evaluate the anti-proliferative activity of PG on A549 cell lines, and cell cycle distribution assay, apoptosis assay, and western blot analysis in vitro were used to explore the possible mechanisms.

Results

From the results of our present study, cell viability was obviously inhibited by PG, in a dose- and time-dependent manner. Our results also suggested that the anti-proliferative effect of PG was related to cell cycle arrest at the G2/M phase through repression of cdc2 and Cyclin B1 protein expression. In addition, the results of apoptosis assay and western blot analysis indicated that the anti-proliferative activity could be related to apoptosis via up-regulating the expressions of Bax, caspase-3 and caspase-7, and down-regulating the expressions of Bcl-2.

Conclusions

In conclusion, the PG has significant anti-proliferative activity on A549 cell lines, and the possible mechanism was related to cell cycle arrest at the G2/M phase, and apoptosis via the regulations of Bax, Bcl-2, and caspase-3 and caspase-7.

In vitro and in vivo antitumor activity of scutebarbatine A on human lung carcinoma A549 cell lines

During our systematic study on the anticancer activities of Scutellaria barbata, scutebarbatine A (SBT-A), one of the major alkaloids in S. barbata, was found to have antitumor effects on A549 cells. Thus, we designed the present study to investigate in detail the antitumor effects of SBT-A. The cytotoxic effect of SBT-A on A549 in vitro were determined by an MTT assay and evaluated by IC50 values. Furthermore, results of Hoechst 33258 and Annexin V/PI staining assays demonstrated that SBT-A had significant antitumor effects on A549 cells via apoptosis, in a concentration-dependent manner. What's more, the mechanism was explored by western blotting, and our study revealed that SBT-A can up-regulate the expressions of cytochrome c, caspase-3 and 9, and down-regulate the levels of Bcl-2 in A549 cells. Finally, the antitumor effects of SBT-A were evaluated in vivo by using transplanted tumor nude mice, and the results confirmed that SBT-A has a notable antitumor effect on A549 cancer via mitochondria-mediated apoptosis. Collectively, our results demonstrated that SBT-A showed significant antitumor effects on A549 cells in vivo and in vitro via mitochondria-mediated apoptosis by up-regulating expressions of caspase-3 and 9, and down-regulating Bcl-2.

Epigenetic regulation of ANKRD18B in lung cancer

The identification of the key genetic and epigenetic changes underlying lung carcinogenesis would aid effective early diagnosis and targeted therapies for lung cancer. In this study, we screened a novel hypermethylated gene ankyrin repeat domain 18B (ANKRD18B), to determine whether it is regulated by DNA methylation and clarify its biological and clinical implications in lung cancer. Methylation status and expression level were analyzed by methylation-specific PCR, bisulfite genomic sequencing, and quantitative reverse transcription-polymerase chain reaction (qRT-PCR). We detected ANKRD18B hypermethylation in 52 of 98 (53.1%) primary lung cancer tissues and in nine of 10 (90%) cell lines, whereas no methylation was seen in 10 normal lung tissue samples. ANKRD18B methylation was more frequently observed in patients with poor differentiation (P < 0.05). Notably, 62 pairs of samples from patients whose tumor tissue showed hypermethylation of ANKRD18B exhibited the same aberrant methylation in 72.7% and 69.7% of their corresponding plasma and sputum samples, respectively; whereas no hypermethylation of ANKRD18B was detected in the sputum and plasma from patients whose tumor sample lacked this alteration. In addition, ANKRD18B mRNA expression was significantly decreased or silenced in lung cancer tissues and cell lines associated with hypermethylation of the ANKRD18B region. Demethylation agent 5-aza-2'-deoxycytidine significantly increased ANKRD18B mRNA expression in lung cancer cell lines. Furthermore, overexpression of ANKRD18B suppressed lung cancer cell growth. These results suggest that the expression of ANKRD18B is regulated by CpG island hypermethylation in lung cancer. Our findings confirm the importance of the identification of new markers of epigenetic dysregulation in cancer.

The relationship between KRAS gene mutations and HLA class I antigen downregulation in the metastasis of non-small cell lung cancer

OBJECTIVE

To investigate the association between v-Ki-ras2 Kirsten rat sarcoma viral oncogene homologue (KRAS) gene mutations and levels of human leucocyte antigen (HLA) class I antigen in primary lung tumours and metastatic lymph nodes of patients with non-small cell lung cancer (NSCLC).

METHODS

Patients with NSCLC undergoing tumour resection were enrolled. KRAS codon 12 mutations were analysed in normal lung and lymph node tissue, primary lung tumours and metastatic lymph nodes using polymerase chain reaction-restriction fragment length polymorphism analysis. HLA class I antigen immunostaining was examined using flow cytometry.

RESULTS

A total of 65 patients participated in the study. All normal lung tissues had positive HLA class I antigen immunostaining. The majority of primary lung tumours (56/65) and all of the metastatic lymph nodes (31/31) had downregulated HLA class I antigen immunostaining. There was a positive correlation between downregulated HLA class I antigen in primary tumours and metastatic lymph nodes. There was a negative correlation between KRAS codon 12 mutations and the level of HLA class I antigen in primary and metastatic tumours.

CONCLUSIONS

KRAS codon 12 mutations appear to be important in the downregulation of HLA class I antigen in NSCLC. Abnormal activation of the oncogenic KRAS pathway might provide a new treatment target for NSCLC.

Diamond-lipid hybrids enhance chemotherapeutic tolerance and mediate tumor regression

Self-assembled nanodiamond-lipid hybrid particles (NDLPs) harness the potent interaction between the nanodiamond (ND)-surface and small molecules, while providing a mechanism for cell-targeted imaging and therapy of triple negative breast cancers. Epidermal growth factor receptor-targeted NDLPs are highly biocompatible particles that provide cell-specific imaging, promote tumor retention of ND-complexes, prevent epirubicin toxicities and mediate regression of triple negative breast cancers.

Molecular profiling in non-small cell lung cancer: a step toward personalized medicine

CONTEXT

Lung carcinoma is the result of sequential accumulation of genetic and epigenetic changes. Lung adenocarcinoma is a heterogeneous disease with diverse somatic mutations, and several of them include the so-called driver mutations, which may serve as "druggable" therapeutic targets. Thus, development of personalized approaches for the treatment of non-small cell lung carcinoma (NSCLC) mandates that pathologists make a precise histologic classification inclusive of routine molecular analysis of such tumors.

OBJECTIVE

To address the molecular mechanisms underlying NSCLC and how this knowledge reflects the multidisciplinary approach in the diagnosis and management of these patients. We will also summarize the current available and investigational personalized therapies for patients with resectable early-stage, unresectable locally advanced, and metastatic NSCLC.

DATA SOURCES

Peer-reviewed published literature and personal experience.

CONCLUSIONS

There are multiple mechanisms involved in the pathogenesis of lung cancer, which operate in parallel and involve pathways of activation and inhibition of various cellular events. Further research is essential to characterize the histologic and mutational profiles of lung carcinomas, which will ultimately translate into improved and more personalized therapeutic management of patients with lung cancer.

Kinase dysfunction and kinase inhibitors

With recent advances in molecular biology, abnormalities in cancer cells that contribute to dysregulation of cell survival and proliferation are being characterized with greater precision. Through this process, key abnormalities in cancer cells involving proteins that regulate signal transduction, migration, mitosis and other critical processes have been identified. Such abnormalities often involve a class of proteins called kinases that act to phosphorylate other proteins in the cell, resulting in activation of these proteins in the absence of appropriate stimulation/regulation. Given their role in tumour biology, substantial effort has been directed at blocking the function of these proteins. Several approaches have been used, including monoclonal antibodies and small molecule inhibitors. While antibodies are primarily directed at cell surface proteins, small molecule inhibitors, also known as kinase inhibitors, target proteins throughout the cell. A variety of kinase inhibitors have been approved for the treatment of human cancers. In some instances, these inhibitors have exhibited significant clinical efficacy, and it is likely that their biological activity will be further enhanced as combination regimens with standard treatment modalities are explored. The use of kinase inhibitors in dogs and cats is relatively recent, although two inhibitors, toceranib (Palladia; Pfizer Animal Health, Madison, NJ, USA) and masitinib (Kinavet; Catalent Pharma Solutions, Somerset, NJ, USA) have been approved by the Federal Drug Administration (USA) for use in dogs. This article reviews the biology of protein kinase dysfunction in human and animal cancers, and the application of specific kinase inhibitors to veterinary cancer patients.

Statins and the risk of lung cancer: a meta-analysis

PURPOSE

Several epidemiologic studies have evaluated the association between statins and lung cancer risk, whereas randomized controlled trials (RCTs) on cardiovascular outcomes provide relevant data as a secondary end point. We conducted a meta-analysis of all relevant studies to examine this association.

METHODS

A systematic literature search up to March 2012 was performed in PubMed database. Study-specific risk estimates were pooled using a random-effects model.

RESULTS

Nineteen studies (5 RCTs and 14 observational studies) involving 38,013 lung cancer cases contributed to the analysis. They were grouped on the basis of study design, and separate meta-analyses were conducted. There was no evidence of an association between statin use and risk of lung cancer either among RCTs (relative risk [RR] 0.91, 95% confidence interval [CI] 0.76-1.09), among cohort studies (RR 0.94, 95% CI 0.82-1.07), or among case-control studies (RR 0.82, 95% CI 0.57-1.16). Low evidence of publication bias was found. However, statistically significant heterogeneity was found among cohort studies and among case-control studies. After excluding the studies contributing most to the heterogeneity, summary estimates were essentially unchanged.

CONCLUSION

The results of our meta-analysis suggest that there is no association between statin use and the risk of lung cancer.

Biomarkers and molecular testing for early detection, diagnosis, and therapeutic prediction of lung cancer

The search for biomarkers in the management of lung cancer involves the use of multiple platforms to examine changes in gene, protein, and microRNA expression. Multiple studies have been published in an attempt to describe early detection, diagnostic, prognostic, and predictive biomarkers using chiefly tissues and blood elements. Studies are characterized by a lack of commonality of specific biomarkers, and a lack of validated, clinically useful markers. The future of biomarker discovery as a means of tailoring therapy for patients with lung cancer will involve next-generation sequencing along with collaborative efforts to integrate and validate candidate markers.

The role of Sox genes in lung morphogenesis and cancer

The human lung consists of multiple cell types derived from early embryonic compartments. The morphogenesis of the lung, as well as the injury repair of the adult lung, is tightly controlled by a network of signaling pathways with key transcriptional factors. Lung cancer is the third most cancer-related death in the world, which may be developed due to the failure of regulating the signaling pathways. Sox (sex-determining region Y (Sry) box-containing) family transcriptional factors have emerged as potent modulators in embryonic development, stem cells maintenance, tissue homeostasis, and cancerogenesis in multiple processes. Recent studies demonstrated that the members of the Sox gene family played important roles in the development and maintenance of lung and development of lung cancer. In this context, we summarize our current understanding of the role of Sox family transcriptional factors in the morphogenesis of lung, their oncogenic potential in lung cancer, and their potential impact in the diagnosis, prognosis, and targeted therapy of lung cancer.

Genetic network and gene set enrichment analysis to identify biomarkers related to cigarette smoking and lung cancer

OBJECTIVES

Cigarette smoking is the most demonstrated risk factor for the development of lung cancer, while the related genetic mechanisms are still unclear.

METHODS

The preprocessed microarray expression dataset was downloaded from Gene Expression Omnibus database. Samples were classified according to the disease state, stage and smoking state. A new computational strategy was applied for the identification and biological interpretation of new candidate genes in lung cancer and smoking by coupling a network-based approach with gene set enrichment analysis.

MEASUREMENTS

Network analysis was performed by pair-wise comparison according to the disease states (tumor or normal), smoking states (current smokers or nonsmokers or former smokers), or the disease stage (stages I-IV). The most activated metabolic pathways were identified by gene set enrichment analysis.

RESULTS

Panels of top ranked gene candidates in smoking or cancer development were identified, including genes involved in cell proliferation and drug metabolism like cytochrome P450 and WW domain containing transcription regulator 1. Semaphorin 5A and protein phosphatase 1F are the common genes represented as major hubs in both the smoking and cancer related network. Six pathways, e.g. cell cycle, DNA replication, RNA transport, protein processing in endoplasmic reticulum, vascular smooth muscle contraction and endocytosis were commonly involved in smoking and lung cancer when comparing the top ten selected pathways.

CONCLUSION

New approach of bioinformatics for biomarker identification and validation can probe into deep genetic relationships between cigarette smoking and lung cancer. Our studies indicate that disease-specific network biomarkers, interaction between genes/proteins, or cross-talking of pathways provide more specific values for the development of precision therapies for lung.

Lung cancer in never smokers--a review

An estimated 10-25% of lung cancers worldwide occur in never smokers, i.e. individuals having smoked less than 100 cigarettes in their lifetime. Lung cancer in never smokers (LCINS) is more frequent in women, although large geographic variations are found. Histologically, adenocarcinomas predominate. The mere existence of LCINS suggests that risk factors other than smoking must be present. Exposure to environmental tobacco smoke (particularly in women) and exposure to workplace carcinogens (particularly in men) are the two most important alternative risk factors. However, a history of either is absent in more than a third of LCINS. The large proportion of women in LCINS suggest a hormonal element that may interact with other identified factors such as hereditary risks, a history of respiratory infections or disease, exposure to air pollution, cooking and heating fumes, or exposure to ionising radiation. The study of genomic polymorphisms finds constitutive DNA variations across subjects according to their smoking status, particularly in genes coding for enzymes that participate in the metabolism of certain carcinogens, in those coding for DNA repair enzymes, or in genes associated with tobacco addiction, or inflammatory processes. The type of molecular mutation in p53 or KRAS varies with smoking status. EGFR mutations are more frequent in never smokers, as are EML4-ALK fusions. The mutually exclusive nature of certain mutations is a strong argument in favour of separate genetic paths to cancer for ever smokers and never smokers. In the present paper we review current clinical and molecular aspects of LCINS.

EZH2 promotes malignant behaviors via cell cycle dysregulation and its mRNA level associates with prognosis of patient with non-small cell lung cancer

BACKGROUND

Epigenetic silencing is a common mechanism to inactivate tumor suppressor genes during carcinogenesis. Enhancer of Zeste 2 (EZH2) is the histone methyltransferase subunit in polycomb repressive complex 2 which mediates transcriptional repression through histone methylation. EZH2 overexpression has been linked to aggressive phenotypes of certain cancers. However, the mechanism that EZH2 played in promoting malignancy in non-small cell lung cancer (NSCLC) remains unclear. In addition, the correlation of EZH2 overexpression and the prognosis of NSCLC patients in non-Asian cohort need to be determined.

METHODOLOGY/PRINCIPAL FINDINGS

Up-regulation of EZH2 was found in NSCLC cells compared with normal human bronchial epithelial cells by western blot assay. Upon EZH2 knockdown using small interfering RNA (siRNA), the proliferation, anchorage-independent growth and invasion of NSCLC cells were remarkably suppressed with profound induction of G1 arrest. Furthermore, the expression of cyclin D1 was notably reduced whereas p15(INK4B), p21(Waf1/Cip1) and p27(Kip1) were increased in NSCLC cells after EZH2-siRNA delivery. To determine whether EZH2 expression contributes to disease progression in patients with NSCLC, Taqman quantitative real-time RT-PCR was used to measure the expression of EZH2 in paired tumor and normal samples. Univariate analysis revealed that patients with NSCLC whose tumors had a higher EZH2 expression had significantly inferior overall, disease-specific, and disease-free survivals compared to those whose tumors expressed lower EZH2 (P = 0.005, P = 0.001 and P = 0.003, respectively). In multivariate analysis, EZH2 expression was an independent predictor of disease-free survival (hazard ratio = 0.450, 95% CI: 0.270 to 0.750, P = 0.002).

CONCLUSIONS/SIGNIFICANCE

Our results demonstrate that EZH2 overexpression is critical for NSCLC progression. EZH2 mRNA levels may serve as a prognostic predictor for patients with NSCLC.

Molecular biology of lung cancer: clinical implications

Lung cancer is a heterogeneous disease clinically, biologically, histologically, and molecularly. Understanding the molecular causes of this heterogeneity, which might reflect changes occurring in different classes of epithelial cells or different molecular changes occurring in the same target lung epithelial cells, is the focus of current research. Identifying the genes and pathways involved, determining how they relate to the biological behavior of lung cancer, and their utility as diagnostic and therapeutic targets are important basic and translational research issues. This article reviews current information on the key molecular steps in lung cancer pathogenesis, their timing, and clinical implications.

Solid tumor cytogenetics: current perspectives

Conventional cytogenetics in conjunction with Fluorescence in Situ Hybridization (FISH) continues to remain an important and integral component in the diagnosis and management of solid tumors. The ability to effectively detect the vast majority of clinically relevant chromosomal aberrations with a rapid-to-acceptable turnaround time makes them the most cost-effective screening/detection tool currently available in modern pathology. In this review, we describe a representative set of solid tumors in which chromosomal analysis and/or FISH plays a significant role in the routine clinical management of solid tumors.