Dakai Xiao

MicroRNA-26a/b Regulate DNA Replication Licensing, Tumorigenesis, and Prognosis by Targeting CDC6 in Lung Cancer

Cancer is characterized by mutations, genome rearrangements, epigenetic changes, and altered gene expression that enhance cell proliferation, invasion, and metastasis. To accommodate deregulated cellular proliferation, many DNA replication-initiation proteins are overexpressed in human cancers. However, the mechanism that represses the expression of these proteins in normal cells and the cellular changes that result in their overexpression are largely unknown. One possible mechanism is through miRNA expression differences. Here, it is demonstrated that miR26a and miR26b inhibit replication licensing and the proliferation, migration, and invasion of lung cancer cells by targeting CDC6. Importantly, miR26a/b expression is significantly decreased in human lung cancer tissue specimens compared with the paired adjacent normal tissues, and miR26a/b downregulation and the consequential upregulation of CDC6 are associated with poorer prognosis of patients with lung cancer. These results indicate that miR26a/b repress replication licensing and tumorigenesis by targeting CDC6. Implications: The current study suggests that miR26a, miR26b, and CDC6 and factors regulating their expression represent potential cancer diagnostic and prognostic markers as well as anticancer targets. Visual Overview: http://mcr.aacrjournals.org/content/12/11/1535/F1.large.jpg. Mol Cancer Res; 12(11); 1535–46. ©2014 AACR. Visual Overview

Expression of gamma-aminobutyric acid receptors on neoplastic growth and prediction of prognosis in non-small cell lung cancer

BackgroundGamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the adult mammalian brain, but exerts physiologic effects other than that on neurotransmitter in non-neuronal peripheral tissues and organs. GABA may affect cancer growth through activation GABA receptors. We investigated the gene expression of GABA receptors in tissue of non-small cell lung cancers (NSCLC) and non-cancerous tissues, and found that the gene expression of GABA receptor phenotypes was correlated with tumorigenesis and clinical prognosis.MethodsSixty-one snap-frozen human samples of NSCLC tissues and paired non-cancerous tissues (5cm away from tumor) were analyzed. Gene expression of GABA receptors was detected by Real-time quantitative PCR (RT-qPCR). Survival times in relation to the expression of GABA receptor phenotypes were analyzed. Human NSCLC cell lines H1299, A549, H520, H460 and human bronchial epithelial cell line BEAS-2B were used to determine the phenotypes of GABA inhibitory effects on cancer cell growth. The effects of exogenous administration of GABA on H1299 cell growth were examined.ResultsThe gene expressions were significantly higher in NSCLC tissues than in the paired non-cancerous tissues for GABAA receptor subunit α3 (GABRA3, P = 0.030); for GABAA receptor subunit epsilon (GABRE, P = 0.036); and GABAB receptor subunit 2 (GABBR2, P = 0.005). Kaplan-Meier curves showed that patients with high expression of GABBR2 gene and low expression of GABRA3 gene had a better prognosis (P < 0.05). The administration of GABA resulted in suppressed proliferation of NSCLC cell lines in a dose- and time-dependent manner. The use of the GABA receptor antagonist CGP35348 could reverse the inhibitory effect.ConclusionsThe pattern of GABA receptor gene phenotype expression may be involved in the regulation of tumorigenesis. A high expression of GABBR2 with a low expression of GABRA3 may predict a better outcome. The treatment with GABA attenuates cancer cell growth in vitro. The expression of GABA receptor may be not only promising genetic therapeutic targets but may also serve as valuable prognostic markers for NSCLC.

Frequent alterations in cytoskeleton remodelling genes in primary and metastatic lung adenocarcinomas

The landscape of genetic alterations in lung adenocarcinoma derived from Asian patients is largely uncharacterized. Here we present an integrated genomic and transcriptomic analysis of 335 primary lung adenocarcinomas and 35 corresponding lymph node metastases from Chinese patients. Altogether 13 significantly mutated genes are identified, including the most commonly mutated gene TP53 and novel mutation targets such as RHPN2, GLI3 and MRC2. TP53 mutations are furthermore significantly enriched in tumours from patients harbouring metastases. Genes regulating cytoskeleton remodelling processes are also frequently altered, especially in metastatic samples, of which the high expression level of IQGAP3 is identified as a marker for poor prognosis. Our study represents the first large-scale sequencing effort on lung adenocarcinoma in Asian patients and provides a comprehensive mutational landscape for both primary and metastatic tumours. This may thus form a basis for personalized medical care and shed light on the molecular pathogenesis of metastatic lung adenocarcinoma.

Analysis of ultra-deep targeted sequencing reveals mutation burden is associated with gender and clinical outcome in lung adenocarcinoma

Gender-associated difference in incidence and clinical outcomes of lung cancer have been established, but the biological mechanisms underlying these gender-associated differences are less studied. Recently we have characterized the genomic landscape of lung adenocarcinoma derived from Chinese population (Reference [1]). In this study we evaluated the clinical significance of mutation burden in lung adenocarcinoma and found that the male tumors harbored statistically greater burden of genetic alterations than female counterparts (Male median 3 (range 0–34) vs female median = 2 (0–24), male to female ratio = 1.636, 95% CI = 1.343–1.992) after adjustment of age at surgery, stage, smoking status. Kaplan-Meier survival analysis revealed that greater burden of genetic alterations was associated with worse overall survival. Moreover, multivariable analysis demonstrated mutation burden was an independent prognostic factor for the patients. Taken together, our analysis demonstrated gender disparity of mutation burden and their prognostic value in lung adenocarcinoma. This gender difference in mutation burden might provide an explanation for the distinct difference in the clinical outcomes between sexes in lung adenocarcinoma.

Integrative analysis of genomic sequencing data reveals higher prevalence of LRP1B mutations in lung adenocarcinoma patients with COPD

Both chronic Obstruction Pulmonary Disease (COPD) and lung cancer are leading causes of death globally. Although COPD and lung cancer coexist frequently, it is unknown whether lung cancer patients with COPD harbor distinct genomic characteristics compared to those without COPD. In this study, we retrospectively analyzed genomic sequencing data from 272 patients with lung adenocarcinoma (LUAD) and compared the genetic alterations in LUAD patients with and without COPD. Integrative analysis of whole-genome and exome sequencing data revealed that COPD and non-COPD groups showed high concordance in mutational burden and spectra. Notably, we also found that EGFR mutations were more prevalent in LUAD patients without COPD, whereas mutated LRP1B was more frequently observed in LUAD patients with COPD. In addition, multi-variable analysis with logistic regression demonstrated that mutation of LRP1B was a predictive marker for the presence of COPD in the patients with LUAD. Our analysis demonstrated for the first time the high concordance in genomic alterations between the tumors from LUAD patients with and without COPD. We also identified higher prevalence of LRP1B among the LUAD patients with COPD, which might help understand the underlying mechanisms which link COPD and lung cancer.

Nomogram prediction for the survival of the patients with small cell lung cancer

BACKGROUND Small cell lung cancer (SCLC) is a subtype of lung cancer with poor prognosis. In this study, we aimed to build a nomogram to predict the survival of individual with SCLC by incorporating significant clinical parameters. METHODS The patients with SCLC were enrolled from the First Affiliated Hospital of Guangzhou Medical University (GMUFAH) between 2009 and 2013. We identified and incorporated the independent prognostic factors to build a nomogram to predict the survival of SCLC patients. The predictive accuracy and discriminative ability of the nomogram were evaluated by concordance index (C-index) and calibration curve. We also compared the accuracy of the built model with the 7th AJCC TNM and VALSG staging system. The nomogram was further validated in an independent cohort of 80 patients with SCLC from Cancer Center of Guangzhou Medical University (GMUCC) between 2009 and 2013. RESULTS A total of 275 patients with SCLC were included in the primary cohort, and seven independent prognostic factors were identified including age, N stage, metastasis status, histology, platelets to lymphocyte ratio (PLR), neuron specific enolase (NSE) and CYFRA21-1 as independent prognostic factors after using Cox regression model. A nomogram incorporating these prognostic factors was subsequently built. The calibration curves for possibilities of 1-, 2-year overall survival (OS) revealed optimal agreement between nomogram prediction and actual observation. The C-index of this nomogram was higher than that of TNM and VALSG staging system in both primary and validation cohort (nomogram vs. TNM, primary cohort 0.68 vs. 0.65, P<0.01, validation cohort 0.66 vs. 0.62, P<0.05; nomogram vs. VALSG, primary cohort 0.68 vs. 0.66, P<0.01, validation cohort 0.66 vs. 0.64, P<0.05). CONCLUSIONS In this study, we established and validated a novel nomogram for the prediction of OS for the patients with SCLC. This model could provide more accurate individual prediction of survival probability of SCLC than the existing staging systems.

Characterization of RNA editome in primary and metastatic lung adenocarcinomas

RNA editing results in post-transcriptional modification and could potentially contribute to carcinogenesis. However, RNA editing in advanced lung adenocarcinomas has not yet been studied. Based on whole genome and transcriptome sequencing data, we identified 1,071,296 RNA editing events from matched normal, primary and metastatic samples contributed by 24 lung adenocarcinoma patients, with 91.3% A-to-G editing on average, and found significantly more RNA editing sites in tumors than in normal samples. To investigate cancer relevant editing events, we detected 67,851 hyper-editing sites in primary and 50,480 hyper-editing sites in metastatic samples. 46 genes with hyper-editing in coding regions were found to result in amino acid alterations, while hundreds of hyper-editing events in non-coding regions could modulate splicing or gene expression, including genes related to tumor stage or clinic prognosis. Comparing RNA editome of primary and metastatic samples, we also discovered hyper-edited genes that may promote metastasis development. These findings showed a landscape of RNA editing in matched normal, primary and metastatic tissues of lung adenocarcinomas for the first time and provided new insights to understand the molecular characterization of this disease.

Prognostic Effect of Albumin-to-Globulin Ratio in Patients with solid tumors: A Systematic Review and Meta-analysis

Background: Albumin and globulin are main components of serum protein. The level of albumin and globulin partially represents the nutrition status and immune system. Albumin-to-globulin ratio (AGR) has been reported as a prognostic factor in various cancers. We therefore performed a meta-analysis to elucidate the prognosis effect of AGR on survival outcomes in solid tumors. Method: Six electronic database were searched for the relevant articles that assessing the prognostic value of pre-treatment AGR in solid tumor patients. The primary outcome was overall survival (OS) and the secondary outcomes were cancer-specific survival (CSS), disease-free survival (DFS) and disease-metastasis-free survival (DMFS). The time-to-event outcomes were summarized in hazard ratio (HR) and 95% confidence interval (CI). Result: A total of 13890 solid tumor patients in 24 studies were included. The AGR higher than the cut-off values ranging from 1.15-1.75 was related to better OS (HR=0.58, 95%CI 0.537-0.626, p<0.0001), CSS (HR=0.287, 95%CI 0.187-0.438, p<0.0001), DFS (HR=0.792, 95%CI 0.715-0.878, p<0.0001) and DMFS (HR=0.595, 95%CI 0.447-0.792, p<0.0001). According to the cut-off values, subgroup analysis showed that AGR had significant prognostic effect on OS in each cut-off intervals (≤1.20, 1.20-1.40 and ≥1.40). Conclusion: Pre-treatment AGR is an effective prognostic factor and high AGR represents an ideal clinical outcome in the solid tumor patients.

SERINC2‑knockdown inhibits proliferation, migration and invasion in lung adenocarcinoma

Serine incorporator 2 (SERINC2) is a member of the SERINC family of transmembrane proteins that incorporate serine into membrane lipids during synthesis. In the present study, the biological function of SERINC2 in lung adenocarcinoma cells was investigated. The data from a previous study and the publicly available Oncomine database were analysed regarding the expression levels of SERINC2 mRNA in lung adenocarcinoma. A lentiviral-based short hairpin RNA (shRNA) was used to suppress SERINC2 expression in lung cancer cells. The effect of SERINC2 expression on lung cancer proliferation was determined using cell counting kit-8 and colony formation assays. The influence on invasion and migration was examined in vitro using Transwell and wound-healing assays, respectively. Phosphorylated protein kinase B (p-AKT) expression levels were assessed by immunoblotting. According to a previous study and Oncomine, expression levels of SERINC2 mRNA are significantly upregulated in tumour tissues compared with those in healthy tissues in patients with lung adenocarcinoma. SERINC2-knockdown by lentiviral-based shRNA inhibited the proliferation, migration and invasion of the H1650 and A549 cells. In addition, p-AKT expression levels were significantly decreased following SERINC2-knockdown. In conclusion, SERINC2-knockdown suppresses lung adenocarcinoma proliferation, migration and invasion through a mechanism that may be associated with phosphatidylinositol 3-kinase/AKT signalling. Based on these findings, SERINC2 serves an important role in the progression of lung adenocarcinoma.

COP9 signalosome subunit CSN5, but not CSN6, is upregulated in lung adenocarcinoma and predicts poor prognosis

Background The COP9 signalosome (CSN) is an evolutionarily conserved complex composed of eight subunits (CSN1-CSN8). Among the CSN subunits, CSN5 and its dimerization partner CSN6 are the only two MPN (Mpr1-Pad1-N-terminal) domain-containing subunits. These two subunits play essential roles in a variety of biological processes, such as cell cycle progression, protein stability and signal transduction. However, their expression patterns and clinical significance in lung cancer are not completely clear. Methods We examined the expressions of both CSN5 and CSN6 in lung adenocarcinoma (LUAD) patients (n=59) using immunohistochemistry analysis, and correlated their expressions with clinicopathological characteristics. MTT cell proliferation assay was performed to determine the effect of CSN5 silencing or overexpression on the growth of lung cancer cells. Knock down or overexpression of CSN5 was confirmed by western blotting. Results CSN5 expression was elevated in tumor cells, compared to the stromal compartment and adjacent normal epithelial cells. Interestingly, CSN5 was also expressed in the macrophages and lymphocytes adjacent to the tumors. Surprisingly, CSN6 was barely detected in the tumor cells of LUAD patients. Furthermore, we also demonstrated that higher levels of CSN5 were correlated with high tumor-node-metastasis (TNM) stage and worse clinical outcomes. Multivariate Cox regression analysis revealed CSN5 was an independently prognostic factor for LUAD patients. Additionally, in cellular model, depletion of CSN5 expression significantly suppressed the growth of lung cancer cells. Conclusions COP9 signalosome subunit CSN5, but not CSN6, is upregulated in LUAD. Moreover, CSN5 is a critical regulator for the growth of lung cancer and represents an independent prognostic factor and a promising therapeutic target for LUAD patients.