The distinctive nature of adenocarcinoma of the lung

Neuroendocrine Differentiation of Lung Cancer Cells Impairs the Activation of Antitumor Cytotoxic Responses in Mice

Lung cancer has the highest mortality among all types of cancer; during its development, cells can acquire neural and endocrine properties that affect tumor progression by releasing several factors, some acting as immunomodulators. Neuroendocrine phenotype correlates with invasiveness, metastasis, and low survival rates. This work evaluated the effect of neuroendocrine differentiation of adenocarcinoma on the mouse immune system. A549 cells were treated with FSK (forskolin) and IBMX (3-Isobutyl-1-methylxanthine) for 96 h to induce neuroendocrine differentiation (NED). Systemic effects were assessed by determining changes in circulating cytokines and immune cells of BALB/c mice immunized with PBS, undifferentiated A549 cells, or neuroendocrine A549_NED cells. A549 cells increased circulating monocytes, while CD4⁺CD8^- and CD4⁺CD8⁺ T cells increased in mice immunized with neuroendocrine cells. IL-2 and IL-10 increased in mice that received untreated A549 cells, suggesting that the immune system mounts a regulated response against adenocarcinoma, which did not occur with A549_NED cells. Cocultures demonstrated the cytotoxic capacity of PBMCs when confronted with A549 cells, while in the presence of neuroendocrine cells they not only were unable to show cytolytic activity, but also lost viability. Neuroendocrine differentiation seems to mount less of an immune response when injected in mice, which may contribute to the poor prognosis of cancer patients affected by this pathology.

High expression of 14-3-3ơ indicates poor prognosis and progression of lung adenocarcinoma

Lung adenocarcinoma (LUAD) is one of the leading causes of cancer-related death worldwide. 14-3-3ơ is an intracellular phosphoserine-binding protein that has been proposed to be involved in tumorigenesis. However, the biofunctional role of 14-3-3ơ and its clinicopathological/prognostic significance in LUAD have remained elusive. In the present study, western blot and immunohistochemical analyses of cancer tissues/cells and the corresponding normal controls were performed to verify that 14-3-3ơ was upregulated in LUAD. Univariate and multivariate logistic regression analysis indicated that high expression of 14-3-3ơ predicted poor overall survival and progression-free survival of patients with LUAD. Furthermore, in vivo and in vitro experiments demonstrated that overexpression of 14-3-3ơ markedly promoted cell proliferation, colony formation, anchorage-independent growth and tumor growth, whereas 14-3-3ơ depletion produced the opposite effects. Of note, 14-3-3ơ was identified as an independent prognostic factor for patients with LUAD. Collectively, the present results revealed that high expression of 14-3-3ơ may serve as an independent biomarker, contributing to poor prognosis and progression of LUAD.

The Role of Mitochondrial miRNAs in the Development of Radon-Induced Lung Cancer

MicroRNAs are short, non-coding RNA molecules regulating gene expression by inhibiting the translation of messenger RNA (mRNA) or leading to degradation. The miRNAs are encoded in the nuclear genome and exported to the cytosol. However, miRNAs have been found in mitochondria and are probably derived from mitochondrial DNA. These miRNAs are able to directly regulate mitochondrial genes and mitochondrial activity. Mitochondrial dysfunction is the cause of many diseases, including cancer. In this review, we consider the role of mitochondrial miRNAs in the pathogenesis of lung cancer with particular reference to radon exposure.

A natural derivative from ethnomedicinal mushroom potentiates apoptosis, autophagy and attenuates cell migration, via fine tuning the Akt signaling in human lung adenocarcinoma cells (A549)

Although comprehensive exertions have been made in late decades for treating advanced lung cancer with inclusive therapies but efficient anti-lung cancer therapeutics are statically inadequate in the clinics. Hence, compelling novel anti-lung cancer drugs are considerably desired. This backdrop enticed us to unveil anticancer efficacy of astrakurkurol, derivative of wild edible mushroom against lung cancer, whose effects have not yet been described. Mechanistic analysis disclosed that sensitizing effect of astrakurkurol is due to cell cycle arrest at G0/G1 phase, increased level of Fas, FADD, decreased ratio of Bax/Bcl-2, and increased cleaved form of caspase 9, 8, and 3. Apart from the induction of apoptosis, it was demonstrated for the first time that astrakurkurol induced an autophagic response as evidenced by the development of acidic vesicular organelles (AVOs) with up-regulation of beclin-1, Atg7, and downregulated p62. Apoptosis and autophagy can be sparked by the same stimuli, which was as evident from the astrakurkurol-induced inactivation of PI3K/AKT signaling. The thorough scanning of the mechanism of crosstalk between apoptosis and autophagy is requisite for prosperous anticancer remedy. Triterpenoid has evidently intensified cytotoxicity, induced apoptosis and autophagy on A549 cells. Besides astrakurkurol could also curb migration and regress the size of tumor in ex ovo xenograft model. All these findings put forth astrakurkurol as a convincing novel anti-cancer agent, for scrutinizing the lung cancer therapies and as a robust contender for future in vitro and in vivo analysis.

GALNT2/14 overexpression correlate with prognosis and methylation: potential therapeutic targets for lung adenocarcinoma

OBJECTIVE

GALNT2/14 are members of the glycosyltransferase protein family, which initiate mucin-type O-glycosylation of peptides in the Golgi apparatus. However, the correlation between GALNT2/14 and disease prognosis and methylation in lung adenocarcinoma (LUAD) remains unclear. Thus, we sought to identify their potential values in LUAD.

METHODS

GALNT2/14 expressions were analyzed using publicly-available datasets. The association between GALNT2/14 and disease prognosis was evaluated. In addition, gene set enrichment analysis (GSEA) and single sample GSEA (ssGSEA) were used to explore the potential biological functions of GALNT2/14. The correlation between the copy number variations and methylation level of GALNT2/14 and their mRNA expressions was analyzed via cBioPortal. Finally, we explored the prognostic value of the GALNT2/14 methylation levels by MethSurv in LUAD.

RESULTS

GALNT2/14 were highly expressed in LUAD tumor tissue than normal tissue (P < 0.001). Multivariate analysis showed that high GALNT2/14 expressions were both an independent prognostic factor. GSEA found that GALNT2/14 expressions were associated with the methylation, gene silencing, and cell division, whereas immune analysis showed that GALNT2/14 expressions positively correlated with the expression level of PD-L1. Finally, the methylation levels of GALNT2/14 negatively correlated with the GALNT2/14 expressions (R = -0.26 and -0.36, P < 0.001, respectively), and patients with GALNT2/14 hypomethylation had worse overall survival than patients with high methylation (P < 0.05).

CONCLUSIONS

This study demonstrated that the overexpression of GALNT2/14 in LUAD can serve as biomarkers for poor prognosis. The biological functions of GALNT2/14 are potentially related to methylation, gene silencing, tumorigenesis, and cell division. These findings help elucidate the role of GALNT2/14 in tumorigenesis and provide additional insight for therapy and prognosis of LUAD.

Integrative Analysis of the Expression of SIGLEC Family Members in Lung Adenocarcinoma via Data Mining

Background: Sialic acid-binding immunoglobulin-type lectin (SIGLEC) family members are involved in regulating immune-cell activation, proliferation, and apoptosis, and they play an important role in tumor development. However, their expression and correlation with immune molecules in lung adenocarcinoma (LUAD) remain unclear. Methods: We utilized Gene Expression Profiling Interactive Analysis, Kaplan-Meier analysis, the limma package in R/Bioconductor, the University of California Santa Cruz Cancer Genome Browser, cBioPortal, STRING, Cytoscape, DAVID, and the Tumor Immune Estimation Resource for gene and protein profiling and analyses. Results: The results showed that SIGLEC10 and SIGLEC15 levels were upregulated in LUAD, whereas SIGLEC1, CD22 (SIGLEC2), CD33, myelin-associated glycoprotein (SIGLEC4), SIGLEC5, SIGLEC6, SIGLEC7, SIGLEC8, SIGLEC11, and SIGLEC14 levels were significantly downregulated, with their low expression associated with poor overall survival. Moreover, we observed high SIGLEC-mutation rates (22%) in LUAD patients, with SIGLEC functions determined as primarily involved in regulating the immune response, signal transduction, inflammatory response, and cell adhesion. Furthermore, we found that SIGLEC expression was significantly correlated with immune-cell infiltration, especially macrophages, neutrophils, and dendritic cells, and highly associated with immune molecules such as CD80, CD86, CD28, B-cell-activating factor, programmed cell death 1 ligand 2, and colony stimulating factor 1 receptor. Conclusion: These results provide insight into the potential molecular mechanism associated with SIGLEC-related development of LUAD, as well as clues for screening biomarkers and therapeutic targets.

Analysis of genes associated with prognosis of lung adenocarcinoma based on GEO and TCGA databases

BACKGROUNDS

Lung adenocarcinoma (LUAD) is one of the most common malignancies, and is a serious threat to human health. The aim of the present study was to assess potential biomarkers for the prognosis of LUAD through the analysis of gene expression microarrays.

METHODS

The gene expression data for GSE118370 was downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) between normal lung and LUAD samples were screened using the R language. The DAVID database was used to analyze the functions and pathways of DEGs. The STRING database was used to the map protein-protein interaction (PPI) networks, and these were visualized with the Cytoscape software. Finally, the prognostic analysis of the hub gene in the PPI network was performed using the Kaplan-Meier tool.

RESULTS

A total of 406 downregulated and 203 upregulated DEGs were identified. The GO analysis results revealed that downregulated DEGs were significantly enriched in angiogenesis, calcium ion binding and cell adhesion. The upregulated DEGs were significantly enriched in the extracellular matrix disassembly, collagen catabolic process, chemokine-mediated signaling pathway and endopeptidase inhibitor activity. The KEGG pathway analysis revealed that downregulated DEGs were enriched in neuroactive ligand-receptor interaction, hematopoietic cell lineage and vascular smooth muscle contraction, while upregulated DEGs were enriched in phototransduction. In addition, the top 10 hub genes and the most closely interacting modules of the top 3 proteins in the PPI network were screened. Finally, the independent prognostic value of each hub gene in LUAD patients was analyzed through the Kaplan-Meier plotter. Seven hub genes (ADCY4, S1PR1, FPR2, PPBP, NMU, PF4, and GCG) were closely correlated to overall survival time.

CONCLUSION

The discovery of these candidate genes and pathways reveals the etiology and molecular mechanisms of LUAD, providing ideas and guidance for the development of new therapeutic approaches to LUAD.

Methylated PTGER4 is better than CA125, CEA, Cyfra211 and NSE as a therapeutic response assessment marker in stage IV lung cancer

Real-time assessment of therapeutic response in patients with advanced lung cancer presents a major challenge throughout the treatment process. Currently, computed tomography imaging is often used; however, it is radiation-based and hysteretic and is not suitable for repeated use as a real-time assessment. Blood biomarkers represent a novel solution for assessing therapeutic response in patients with advanced lung cancer. In the present study, the efficacy of a methylation marker [methylated prostaglandin E receptor 4 (mPTGER4)] and four protein markers [carcinoma antigen 125 (CA125), carcinoembryonic antigen (CEA), cytokeratin 19-fragments (cyfra21-1) and neuron-specific enolase (NSE)] were simultaneously evaluated to determine their potential in facilitating therapeutic response monitoring as well as their prognostic values in patients with stage IV lung cancer. The results indicated that, following treatment, the blood levels of methylated PTGER4 and NSE had significantly decreased, and mPRGER4, CA125, CEA and NSE exhibited a significant decrease in percentage level. Since mPTGER4 exhibited a higher rate of positive detection prior to therapy, and a greater response of sensitivity to therapy compared to the protein markers, it may represent an improved marker for the monitoring of therapeutic response. The efficacy of the markers in predicting the overall survival (OS) rate of patients with stage IV lung cancer was also assessed. Results from the follow-up of patients (up to 891 days) revealed that the blood levels of mPTGER4, CA125 and NSE before treatment were able to predict overall survival (OS) rate. Additionally, the percentage change in expression levels of CA125, CEA and NSE was also able to predict the OS rate. In conclusion, the present results indicate that mPTGER4 represents an improved biomarker for monitoring therapeutic efficacy compared with CA125, CEA, Cyfra21-1 and NSE. In predicting the long-term survival of patients with stage IV lung cancer; however, the pre-treatment levels of mPTGER4, CA125 and NSE and the percentage changes of CA125, CEA and NSE may be used as the markers.

Santamarine Inhibits NF-κB Activation and Induces Mitochondrial Apoptosis in A549 Lung Adenocarcinoma Cells via Oxidative Stress

Santamarine (STM), a sesquiterpene lactone component of Magnolia grandiflora and Ambrosia confertiflora, has been shown to possess antimicrobial, antifungal, antibacterial, anti-inflammatory, and anticancer activities. However, no study has yet been conducted to investigate the molecular mechanism of STM-mediated anticancer activity. In the present study, we found that STM inhibits growth and induces apoptosis in A549 lung adenocarcinoma cells through induction of oxidative stress. STM induces oxidative stress by promoting reactive oxygen species (ROS) generation, depleting intracellular glutathione (GSH), and inhibiting thioredoxin reductase (TrxR) activity in a dose-dependent manner. Further mechanistic study demonstrated that STM induces apoptosis by modulation of Bax/Bcl-2 expressions, disruption of mitochondrial membrane potential, activation of caspase-3, and cleavage of PARP in a dose-dependent manner. Moreover, STM inhibited the constitutive and inducible translocation of NF-κBp65 into the nucleus. IKK-16 (I-κB kinase inhibitor) augmented the STM-induced apoptosis, indicating that STM induces apoptosis in A549 cells at least in part through NF-κB inhibition. Finally, STM-induced apoptosis and expressions of apoptosis regulators were effectively inhibited by thiol antioxidant N-acetyl-L-cysteine (NAC), indicating that STM exerts its anticancer effects mainly through oxidative stress. To the best of our knowledge, this is the first report providing evidence of anticancer activity and molecular mechanism of STM.

Rac3 Regulates Cell Invasion, Migration and EMT in Lung Adenocarcinoma through p38 MAPK Pathway

Background: The role of Rac3 in cell proliferation in lung adenocarcinoma has been tackled in our previous study. However, the role of Rac3 in cell invasion and migration of lung adenocarcinoma is still not clear. Methods: The expression of Rac3 in lung adenocarcinoma specimens and paired noncancerous normal tissues were evaluated by immunohistochemistry. Lentivirus-mediated RNA interference (RNAi) was employed to silence Rac3 in lung adenocarcinoma cell lines A549 and H1299. A p38 MAPK inhibitor (LY2228820) was employed to inhibit activity of p38 MAPK pathway. Cell invasion and migration in vitro were examined by invasion and migration assays, respectively. PathScan® intracellular signaling array kit and western blot were employed in mechanism investigation. Results: Rac3 expression was frequently higher in lung adenocarcinoma than paired noncancerous normal tissues. Rac3 expression was an independent risk factor for lymphonode metastasis, and was associated with worse survival outcome. Silencing of Rac3 inhibited cell invasion and cell migration in lung adenocarcinoma cell lines. Knockdown of Rac3 decreased activity of p38 MAPK pathway. LY2228820, which was an important p38 MAPK inhibitor, inhibited Rac3-induced cell invasion and migration of lung adenocarcinoma. E-cadherin expression was increased and vimentin expression was decreased after silencing of Rac3 or following the treatment of LY2228820. Conclusions: Our findings suggest that Rac3 regulates cell invasion, migration and EMT via p38 MAPK pathway. Rac3 may be a potential biomarker of invasion and metastasis for lung adenocarcinoma, and knockdown of Rac3 may potentially serve as a promising therapeutic target for lung adenocarcinoma.

Diagnostic MicroRNA Biomarker Discovery for Non-Small-Cell Lung Cancer Adenocarcinoma by Integrative Bioinformatics Analysis

Lung cancer is the leading cause of cancer death and its incidence is ranked high in men and women worldwide. Non-small-cell lung cancer (NSCLC) adenocarcinoma is one of the most frequent histological subtypes of lung cancer. The aberration profile and the molecular mechanism driving its progression are the key for precision therapy of lung cancer, while the screening of biomarkers is essential to the precision early diagnosis and treatment of the cancer. In this work, we applied a bioinformatics method to analyze the dysregulated interaction network of microRNA-mRNA in NSCLC, based on both the gene expression data and the microRNA-gene regulation network. Considering the properties of the substructure and their biological functions, we identified the putative diagnostic biomarker microRNAs, some of which have been reported on the PubMed citations while the rest, that is, miR-204-5p, miR-567, miR-454-3p, miR-338-3p, and miR-139-5p, were predicted as the putative novel microRNA biomarker for the diagnosis of NSCLC adenocarcinoma. They were further validated by functional enrichment analysis of their target genes. These findings deserve further experimental validations for future clinical application.

Orai3 is a predictive marker of metastasis and survival in resectable lung adenocarcinoma

Orai3 channel has emerged as important player in malignant transformation. Indeed, its expression is increased in cancer and favors cell proliferation and survival by permitting calcium influx. In this study, Orai3 was overexpressed in lung adenocarcinoma as compared to their matched non-tumour samples and was associated with tumoural aggressiveness. Moreover, its expression was associated with estrogen receptor alpha (ERα) expression and visceral pleural invasion in multivariate analysis. Furthermore, both the overall survival (OS) median and the metastasis free survival (MFS) median of tumors with high Orai3 expression were lower than in low Orai3 expression regardless of cancer stage (35.01 months vs. 51.11 months for OS and 46.01 months vs. 62.04 months for MFS). In conclusion, Orai3 protein level constitutes an independent prognostic marker in lung adenocarcinoma, and a novel prognostic marker that could help selecting the patients with worst prognosis to be treated with adjuvant chemotherapy in resectable stage.

Specific KRAS amino acid substitutions and EGFR mutations predict site-specific recurrence and metastasis following non-small-cell lung cancer surgery

Background:

We aimed to evaluate whether EGFR mutations (mEGFR) and KRAS amino acid substitutions can predict first site of recurrence or metastasis after non-small-cell lung cancer (NSCLC) surgery.

Methods:

Data were reviewed from 481 patients who underwent thoracic surgery for NSCLC between 2007 and 2012.

Results:

Patients with KRAS G12C developed significantly more bone metastases compared with the remainder of the cohort (59% vs 16%, P<0.0001). This was confirmed in multivariate analysis (MA) (odds ratio (OR): 0.113 (95% confidence interval (CI): 0.055–0.231), P<0.0001). Significantly, more patients with mEGFR developed liver and brain metastases compared with the remainder of the cohort (30% vs 10%, P=0.006; 59% vs 1%, P<0.0001, respectively). These were confirmed in MA (OR: 0.333 (95% CI: 0.095–0.998), P=0.05; OR: 0.032 (95% CI: 0.008–0.135), P<0.0001, respectively). Patients with KRAS G12V developed significantly more pleuro-pericardial metastases compared with the remainder of the cohort (94% vs 12%, P<0.0001). This was confirmed in MA (OR: 0.007 (95% CI: 0.001–0.031), P<0.0001). Wild-type patients developed significantly more lung metastases (35% vs 10%, P<0.0001). This was confirmed in MA (OR: 0.383 (95% CI: 0.193–0.762), P=0.006).

Conclusion:

Epidermal growth factor receptor mutation and KRAS amino acid substitutions seem to predict site-specific recurrence and metastasis after NSCLC surgery.