Survival Of Lung Adenocarcinoma Patients Research Articles

Comprehensive analysis of a novel signature incorporating lipid metabolism and immune-related genes for assessing prognosis and immune landscape in lung adenocarcinoma.

BackgroundAs the crosstalk between metabolism and antitumor immunity continues to be unraveled, we aim to develop a prognostic gene signature that integrates lipid metabolism and immune features for patients with lung adenocarcinoma (LUAD).MethodsFirst, differentially expressed genes (DEGs) related to lipid metabolism in LUAD were detected, and subgroups of LUAD patients were identified via the unsupervised clustering method. Based on lipid metabolism and immune-related DEGs, variables were determined by the univariate Cox and LASSO regression, and a prognostic signature was established. The prognostic value of the signature was evaluated by the Kaplan–Meier method, time-dependent ROC, and univariate and multivariate analyses. Five independent GEO datasets were employed for external validation. Gene set enrichment analysis (GSEA), gene set variation analysis (GSVA), and immune infiltration analysis were performed to investigate the underlying mechanisms. The sensitivity to common chemotherapeutic drugs was estimated based on the GDSC database. Finally, we selected PSMC1 involved in the signature, which has not been reported in LUAD, for further experimental validation.ResultsLUAD patients with different lipid metabolism patterns exhibited significant differences in overall survival and immune infiltration levels. The prognostic signature incorporated 10 genes and stratified patients into high- and low-risk groups by median value splitting. The areas under the ROC curves were 0.69 (1-year), 0.72 (3-year), 0.74 (5-year), and 0.74 (10-year). The Kaplan–Meier survival analysis revealed a significantly poorer overall survival in the high-risk group in the TCGA cohort (p < 0.001). In addition, both univariate and multivariate Cox regression analyses indicated that the prognostic model was the individual factor affecting the overall survival of LUAD patients. Through GSEA and GSVA, we found that tumor progression and inflammatory and immune-related pathways were enriched in the high-risk group. Additionally, patients with high-risk scores showed higher sensitivity to chemotherapeutic drugs. The in vitro experiments further confirmed that PSMC1 could promote the proliferation and migration of LUAD cells.ConclusionsWe developed and validated a novel signature incorporating both lipid metabolism and immune-related genes for all-stage LUAD patients. This signature can be applied not only for survival prediction but also for guiding personalized chemotherapy and immunotherapy regimens.

Prognostic Signature, Immune Features, and Therapeutic Responses of a Novel Ubiquitination-Related Gene Signature in Lung Adenocarcinoma.

Growing studies have implicated the association of ubiquitination-related genes (UbRGs) with the cancer progression and the long-term survival of patients. However, the prognostic values of UbRGs in lung adenocarcinoma (LUAD) have not been investigated. Our study aimed to establish a ubiquitination-related model for prognosis prediction and internal mechanism investigation. The transcriptome expression profiles and corresponding clinical information of LUAD were obtained from TCGA and GEO datasets. Differentially expressed genes (DEGs) were screened between LUAD specimens and nontumor specimens. Kaplan–Meier analysis and univariate assays were carried out on DEGs to preliminarily screen survival-related UbRGs. Then, the LASSO Cox regression model was applied to develop a multigene signature, which was then demonstrated in two GEO datasets by the use of Kaplan-Meier, ROC, and Cox analyses. We estimated the immune cell infiltration in tumor microenvironment via CIBERSORT and immunotherapy response through the TIDE algorithm. In this study, a total of 71 ubiquitination-related DEGs were identified. Nine UbRGs, including TUBA4A, TRIM2, PLK1, ARRB1, TRIM58, PLK1, ARRB1, CCNB1, TRIM6, PTTG1, and CCT2, were included to establish a risk model, which was validated in TCGA and GEO datasets. The multivariate assays demonstrated that the 9-UbRGs signature was a robust independent prognostic factor in the overall survival of LUAD patients. The abundance of CD8 T cells, activated CD4 T memory cells, resting NK cells and macrophages was higher in the high-risk group, and the TMB of high-risk group was statistically higher than the low-risk group. Multiple drugs approved by FAD, targeting UbRGs, were available for the treatment of LUAD. Overall, we identified a nine ubiquitination-related gene signature, and the signature may be applied to be a potential biomarker for CD8 T cells response and clinical responses to immune checkpoint inhibitors for LUAD.

Spatial intra-tumor heterogeneity is associated with survival of lung adenocarcinoma patients

Intra-tumor heterogeneity (ITH) of human tumors is important for tumor progression, treatment response, and drug resistance. However, the spatial distribution of ITH remains incompletely understood. Here, we present spatial analysis of ITH in lung adenocarcinomas from 147 patients using multi-region mass spectrometry of >5,000 regions, single-cell copy number sequencing of ~2,000 single cells, and cyclic immunofluorescence of >10 million cells. We identified two distinct spatial patterns among tumors, termed clustered and random geographic diversification (GD). These patterns were observed in the same samples using both proteomic and genomic data. The random proteomic GD pattern, which is characterized by decreased cell adhesion and lower levels of tumor-interacting endothelial cells, was significantly associated with increased risk of recurrence or death in two independent patient cohorts. Our study presents comprehensive spatial mapping of ITH in lung adenocarcinoma and provides insights into the mechanisms and clinical consequences of GD.

A novel pyroptosis related genes signature for predicting prognosis and estimating tumor immune microenvironment in lung adenocarcinoma.

BackgroundPyroptosis is a newly found form of programmed cell death, accompanied by inflammatory response as well as immune response. Here, the specific function and prognosis predictive of pyroptosis-related genes (PRGs) were systematically explored in lung adenocarcinoma (LUAD).MethodsThe gene expression data and corresponding clinical information of LUAD patients were obtained from The Cancer Genome Atlas (TCGA), and the expression level of PRGs was identified between normal and tumor tissues. Furthermore, univariate Cox proportional hazards regression was conducted to filter the PRGs related to overall survival, and least absolute shrinkage and selection operator (LASSO) regression was subsequent employed to establish the PRGs risk model. Besides, the correlation of risk score with patients’ clinical features, tumor mutational burden (TMB) as well as tumor microenvironment (TME) was also investigated.ResultsA total of 5 PRGs (NLRC4, NLRP1, NLRP3, NOD1, PLCG1, and BAK1) was used to establish the risk prognostic model. According the median value of risk score, all the patients were classified into low- and high-risk score group. Kaplan-Meier analysis indicted that the LUAD patients in low-risk group exhibited a better survival outcome compared the patients in high-risk group (P<0.001). After adjusting for age, gender, and clinical stage, the risk score was also considered as and independent risk factor affecting the overall survival of LUAD patients (HR =2.949, 95% CI: 1.762–4.937). Moreover, low-risk score group exhibited a higher Immune score and lower Tumor purity compared with high-risk score group. ssGSEA results proved that the enrichment scores of most immune cells and immune related signal pathway in low-risk score group was significant higher than that in high-risk score group. In addition, the PRGs risk score was also positive correlated with TMB in LUAD tissues.ConclusionsIn this study, a novel prognostic model based on PRGs was constructed and used to predict the survival outcome of LUAD patients. In addition, the PRGs risk signature was also associated with TMB and anti-tumor immune environment. The induction of pyroptosis inside tumors might be considered a potential strategy in cancer treatments.

PLK1 Is a Potential Prognostic Factor Associated with the Tumor Microenvironment in Lung Adenocarcinoma.

More than 40% of lung cancers are lung adenocarcinoma (LUAD) worldwide. However, the prognosis of LUAD is poor for the lack of effective treatment methods. Our study identified PLK1 as a novel prognosis biomarker and treatment target for LUAD. Based on the Cancer Genome Atlas (TCGA) database, differentially expressed genes (DEGs) from 551 LUAD cases were analyzed for the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. To explore the biological pathways and the tumor-infiltrating immune cells (TICs) using gene set variation analysis (GSVA) and the CIBERSORT, as well as to analyze DEGs, a protein-protein interaction (PPI) network and Cox regression analysis were performed. Validation of DEGs was achieved through quantitative real-time PCR (qPCR) and immunoblotting. DEGs associated with the cell cycle were sorted out. Cell cycle scores were positively correlated with age, clinical stages, and metastasis and negatively correlated with overall survival of LUAD patients. PPI and Cox analyses showed that PLK1 could be a prognostic factor for LUAD patients. CIBERSORT analysis revealed a positive correlation between the transcription level of PLK1 and the function of CD8+ and activated memory CD4+ T cells, as well as a negative correlation with activated natural killer cells. Furthermore, PLK1 overexpression increased immune cytotoxicity, as measured by the cytolytic activity score, IFN- score, and IFN- level. There is a strong correlation between PLK1 and key features of TICs, indicating its potential as a promising prognostic biomarker for LUAD.

Associations of IFT20 and GM130 protein expressions with clinicopathological features and survival of patients with lung adenocarcinoma

BackgroundLung cancer is the leading cause of malignancy-related mortality and lung adenocarcinoma accounts for about 40% of lung malignancies. The aim of this study was to investigate the associations of intraflagellar transport protein 20 (IFT20) and Golgi matrix protein 130 (GM130) expression with clinicopathological features and survival in patients with lung adenocarcinoma.MethodsThe expressions of IFT20 and GM130 protein in cancerous and matched adjacent lung tissues of 235 patients with lung adenocarcinoma were assessed by tissue microarray and immunohistochemistry, which were indicated by the mean optical density (IOD/area), the rate of positive staining cells and staining intensity score. The correlation between IFT20 and GM130 protein was assessed by Spearman’s rank correlation. Associations of IFT20 and GM130 protein expression with clinicopathological features of patients were analyzed by multivariate logistic regression models. The survival analysis of patients was performed by Cox proportional hazard regression models.ResultsWith adjustment for multiple potential confounders, each one-point increase in IFT20 protein staining intensity score was significantly associated with 32% and 29% reduced risk for TNM stage in II ~ IV and lymphatic metastasis of patients, respectively (P < 0.05). And each one-point increase in GM130 protein staining intensity score was associated with a significant reduction in the risk of poor differentiation and tumors size > 7 cm by 29% and 38% for lung adenocarcinoma patients, respectively (P < 0.05). In stratified Cox model analysis, enhanced IFT20 staining intensity score was significantly decreased the risk of death by 16% for patients without distant metastasis. And elevated the IOD/area of GM130 expression significantly decreased the death risk of lung adenocarcinoma patients with tumor size > 7 cm or distant metastasis by 54% and 65%, respectively (P < 0.05).ConclusionIFT20 and GM130 protein expressions were negatively associated with tumor differentiated types, size, TNM stage and lymphatic metastasis of lung adenocarcinoma. Both IFT20 and GM130 proteins have some protective effects on the survival of lung adenocarcinoma patients with specific clinicopathological features.

Bioinformatics Analysis of Prognostic Significance and Immune Characteristics of CXC Chemokine Family in Patients with Lung Adenocarcinoma.

Objective To screen CXC chemokines related to the risk of lung adenocarcinoma (LUAD) using bioinformatics and construct a CXC-based prognostic risk model to improve the diagnosis and treatment of LUAD patients. Methods The Cancer Genome Atlas (TCGA) database and Gene Expression Omnibus (GEO) database were searched to obtain mRNA expression data and clinicopathological information of LUAD patients. CXC genes differentially expressed in LUAD were screened using the R packages. Further, risk factors significantly associated with the survival of LUAD patients were obtained by the univariate Cox proportional hazard regression, LASSO regression, and multivariate Cox proportional hazard regression analysis, following which a risk prediction model was constructed. The performance of the CXCL13-based model in predicting the prognosis of low-risk and high-risk effect LUAD patients was verified, and the association between the model and the degree of tumor immune cell infiltration was investigated. Results CXCL13 was significantly highly expressed in the cancer tissues of LUAD patients. The risk of death in patients with highly expressed CXCL13 was about 1.5 times higher than in those with lowly expressed CXCL13 (HR = 1.5153357). CXCL13-based risk scoring showed that the high-risk score of LUAD patients was significantly correlated with poor prognosis, but no relation between the two was found in the GEO validation sets, suggesting that this risk model may not be accurate enough. In addition, activated B cells, CD4+ T cells, CD8+ T cells, and dendritic cells were significantly positively correlated with the high risk of LUAD. Conclusions Although we found that a high expression of CXCL13 was associated with a high risk of death and immune cell infiltration and activation in LUAD patients, the CXCL13-based risk model was not accurate enough for predicting the prognosis of LUAD patients.

GPR87 promotes tumor cell invasion and mediates the immunogenomic landscape of lung adenocarcinoma

The purpose of this study is to examine the association between G protein-coupled receptor 87 (GPR87) and lung adenocarcinoma (LUAD) metastasis and immune infiltration. The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets extract clinical data. According to the TCGA database, increased GPR87 expression predicts poor overall survival, progression-free interval, and disease-specific survival in LUAD patients. The meta-analysis also reveals a significant association between high GPR87 expression and poor overall survival. Moreover, functional experiments demonstrate that GPR87 silencing reduces LUAD cell invasion and migration. Immunoblotting shows that GPR87 knockdown decreased Vimentin and N-cadherin expression and increased E-cadherin expression in LUAD cells. GPR87 expression in LUAD is positively correlated with immune infiltration. In addition, GPR87 expression is associated with immune and chemotherapy resistance in LUAD patients. Our findings indicate that GPR87 promotes tumor progression and is correlated with immune infiltration, suggesting GPR87 as a possible biomarker for prognosis prediction in LUAD.

EphrinA3 is a key regulator of malignant behaviors and a potential prognostic factor in lung adenocarcinoma.

As a member of the Ephrin protein family that elicits short distance cell-cell signaling, EphrinA3 has been shown to promote or inhibit tumorigenesis depending on tumor types, but its roles and the underlying mechanisms in lung adenocarcinoma (LUAD) have not been reported. The TCGA database and Kaplan-Meier Plotter database were used to analyze the differential expression of EphrinA3 between LUAD and para-carcinoma tissues, and its effect on overall survival of LUAD patients. CCK-8 assay, Edu assay, and flow cytometry were used to probe the effect of EphrinA3 on the proliferation of LUAD cells, and transwell assay was employed to examine its effect on migration and invasion. In addition, the effect of EphrinA3 on the growth of LUAD was further evaluated using a xenograft tumor model. EphrinA3 was expressed highly in LUAD, and its expression level was negatively correlated with the prognosis of LUAD patients. In addition, EphrinA3 promoted proliferation, migration, and invasion of LUAD cells, and accelerated tumor growth in a xenograft LUAD model. The reported EphrinA3 receptors, EphA1 and EphA10, were expressed in clinical LUAD tissues and co-localized with EphrinA3 in LUAD cells. Mechanistically, EphrinA3/Eph signaling activated AKT, ERK, and p38MAPK, induced epithelial-mesenchymal transition (EMT), and upregulated matrix metalloproteases-2 and -9 (MMP-2/-9). EphrinA3 expression was negatively correlated with prognosis of patients with LUAD. EphrinA3 promoted proliferation, migration, and invasion of LUAD cells. EphrinA3 enhanced the phosphorylation of ERK and AKT, and potentiates EMT and MMP expression in LUAD cells.

Prognostic Impact of the Angiogenic Gene POSTN and Its Related Genes on Lung Adenocarcinoma.

BackgroundThe function of angiogenesis-related genes (ARGs) in lung adenocarcinoma (LUAD) remains poorly documented. This study was designed to reveal ARGs in LUAD and related networks.MethodsWe worked with sequencing data and clinical information pertaining to LUAD from public databases. ARGs were retrieved from the HALLMARK_ANGIOGENESIS gene set. Differential analysis and Kaplan–Meier (K–M) analysis were performed to authenticate the ARGs associated with LUAD. Weighted gene correlation network analysis was performed on the mining hub genes linked to the abovementioned genes, and functional enrichment analysis was done. Subsequently, Cox regression analyses were used to construct the prognostic gene. POSTN and microvessel density were detected using immunohistochemistry.ResultsPOSTN, an ARG that was highly expressed in patients with LUAD and was closely associated with their weak overall survival was identified. Differentially expressed genes associated with POSTN were mainly enriched in entries related to the tubulointerstitial system, immune response, and epithelial cells. A positive correlation was demonstrated between POSTN expression and tumor microvessel density in LUAD. Subsequently, a prognostic gene signature was constructed and revealed that 4 genes may predict the survival of LUAD patients. Furthermore, the ESTIMATE and CIBERSORT analyses suggested that our risk scoring system may be implicated in altering the immune microenvironment of patients with LUAD. Finally, a ceRNA network was constructed based on the prognostic genes, and the regulatory networks were examined.ConclusionPOSTN, a novel prognostic gene signature associated with ARGs, was constructed for the prognosis of patients with LUAD. This signature may alter the immune microenvironment by modulating the activation of the tubulointerstitial system, epithelial cells, and immune cells, ultimately affecting patient survival.

The Risk Model Based on the Three Oxidative Stress-Related Genes Evaluates the Prognosis of LAC Patients.

Background Oxidative stress plays a role in carcinogenesis. This study explores the roles of oxidative stress-related genes (OSRGs) in lung adenocarcinoma (LAC). Besides, we construct a risk score model of OSRGs that evaluates the prognosis of LAC patients. Methods OSRGs were downloaded from the Gene Set Enrichment Analysis (GSEA) website. The expression levels of OSRGs were confirmed in LAC tissues of the TCGA database. GO and KEGG analyses were used to evaluate the roles and mechanisms of oxidative stress-related differentially expressed genes (DEGs). Survival, ROC, Cox analysis, and AIC method were used to screen the prognostic DEGs in LAC patients. Subsequently, we constructed a risk score model of OSRGs and a nomogram. Further, this work investigated the values of the risk score model in LAC progression and the relationship between the risk score model and immune infiltration. Results We discovered 163 oxidative stress-related DEGs in LAC, involving cellular response to oxidative stress and reactive oxygen species. Besides, the areas under the curve of CCNA2, CDC25C, ERO1A, CDK1, PLK1, ITGB4, and GJB2 were 0.970, 0.984, 0.984, 0.945, 0.984, 0.771, and 0.959, respectively. This indicates that these OSRGs have diagnosis values of LAC and are significantly related to the overall survival of LAC patients. ERO1A, CDC25C, and ITGB4 overexpressions were independent risk factors for the poor prognosis of LAC patients and were associated with risk scores in the risk model. High-risk score levels affected the poor prognosis of LAC patients. Notably, a high-risk score may be implicated in LAC progression via cell cycle, DNA replication, mismatch repair, and other mechanisms. Further, ERO1A, CDC25C, and ITGB4 expression levels were related to the immune infiltrating cells of LAC, including mast cells, NK cells, and CD8 T cells. Conclusion In summary, ERO1A, CDC25C, and ITGB4 of OSRGs are associated with poor prognosis of LAC patients. We confirmed that the risk model based on the ERO1A, CDC25C, and ITGB4 is expected to assess the prognosis of LAC patients.

Abstract 3839: RASSF1C and tumor microenvironment

Abstract Introduction: Tumor microenvironment (TME) plays a vital role in tumor invasion and metastasis and provides a rich environment for identifying novel therapeutic targets. The TME landscape consists of extracellular matrix (ECM) and stromal cells. ECM is a major component of TME that mediates interaction between cancer cells and stromal cells to promote invasion and metastasis. We have shown in published work that RASSF1C promotes cancer stem cell development, migration, and drug resistance, in part, by promoting EMT through a mechanism that involves up-regulation of the PIWIL1-piRNA gene axis. Interestingly, one of the target genes identified by our microarray study to be upregulated by RASSF1C is P4HA2. In cancer, P4H2A is vital for collagen posttranslational modification and folding. This leads to formation of a stiff ECM and induction of cancer stem cell marker gene expression, resulting in metastatic dissemination. High expression of P4HA2 is associated with significantly lower survival of lung cancer patients. Thus, RASSF1C could promote tumor cell ECM remodeling to induce lung cancer cell stemness, invasion and metastasis by up-regulating a novel PIWIL1-P4HA2 gene axis expression. Methods: Analysis of a microarray study using H1299 cells over-expressing RASSF1C or control vector backbone identified P4HA2 as a RASSF1C gene target. RT-PCR, immunoblots, and immunofluorescence techniques were used to confirm P4HA2 gene expression using specific primers and antibodies in cells over-expressing RASSF1C or PIWIL1 along with control cells. Kaplan-Meier analysis was performed to determine the relationship of P4HA2 expression to lung adenocarcinoma patient survival using data from The Cancer Genome Atlas (TCGA). Results: Analysis of microarray data from H1299 cells over-expressing RASSF1C or control vector backbone shows that RASSF1C up-regulates P4HA2 gene expression 2-fold. The up-regulation of P4HA2 expression by RASSF1C was confirmed by RT-PCR, immunoblots, and immunofluorescence using P4HA2 gene specific primers and antibodies. Further, H1299 cells over-expressing PIWIL1 show increased P4HA2 gene expression on immunoblots. Kaplan-Meier analysis shows that high P4HA2 expression in lung adenocarcinoma patients negatively correlates with patient survival. Thus, our findings suggest the hypothesis that RASSF1C may promote lung cancer cell ECM remodeling to induce lung cancer cell stemness, invasion and metastasis, in part, by up-regulating a novel pathway involving a PIWIL1-P4HA2 gene axis. Conclusions: Investigating the role of a RASSF1C-PIWIL1-P4HA2 gene axis in ECM remodeling in lung cancer cells will provide important mechanistic information that could, in turn, lead to identification of useful biomarkers for lung cancer prognosis and targets for therapy. Citation Format: Yousef G. Amaar, Mark E. Reeves. RASSF1C and tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3839.

Identification of hub genes, modules and biological pathways associated with lung adenocarcinoma: A system biology approach

Lung adenocarcinoma (LUAD) is the most common non-small cell lung cancer with an alarming trend within non-smokers at younger ages. This study is designed to identify mechanisms of LUAD compared to normal lung tissues using systems biology approaches. Four GSE datasets (GSE75037, GSE63459, GSE32863 and GSE10072) were selected from the Gene Expression Omnibus database. Data processing and meta-analysis were performed using the R statistical programming language. The common and unique DEGs between stages of LUAD and normal lung tissues were initiated by the Venny tool. Common genes were then analyzed in a STRING database to obtain protein-protein interaction. STRING output was analyzed by MCODE and CytoHubba applications of Cytoscape to identify modules of co-expression and hub genes, respectively. The correlation between hub genes and survival of LUAD patients was explored using UALCAN. The hub genes from the meta-analysis were confirmed using an independent, comprehensive LUAD RNA-sequencing dataset collected from The Cancer Genome Atlas (TCGA). The shared upregulated and downregulated DEGs among LUAD stages were 22 and 140 genes, respectively, when compared to normal lung tissues. Unique genes for each stage were also identified. The hub genes were PECAM1, TEK, CDH5, VWF and ANGPT1. An inverse correlation was found between the expression levels of ANGPT1 gene and overall survival of LUAD patients (p-value = 0.02). Most of the top cluster genes were enriched for Gα(s) signalling events, GPCR ligand binding, class B/2 (Secretin family receptors), platelet activation, signalling and aggregation in the main three co-expression clusters. Most of the shared genes were enriched in the biological pathway of hemostasis. TCGA analysis showed that hub genes derived from common genes were found statistically significant throughout all stages. In conclusion, unique upregulated and downregulated DEGs at each stage were identified with FERMT1 and SIX1 as specific early-stage diagnostic biomarkers for stage IB and IIB. 5 hub genes were observed, including PECAM1, TEK, CDH5, vWF and ANGPT1 which might be crucial for the onset and progression of LUAD. Interestingly, ANGPT1 can be considered as a potential and valuable prognostic marker in LUAD patients.

The prognostic value of N6-methyladenosine RBM15 regulators in lung adenocarcinoma.

N6-methyladenosine (m6A) is the most common internal modification in mammalian mRNAs while RNA-binding motif protein 15 (RBM15) is an important methyltransferase in m6A modification. Increasing evidences have shown that RBM15 has a close correlation with lung cancer. However, specific functions of RBM15 in lung adenocarcinoma (LUAD) are limited. RBM15 expression was analyzed in human LUAD tissues and matched healthy lung tissue. RBM15 was knocked down via siRNA in A549 and H1734 cells. The relationships between RBM15 with cellular functions characteristics and mRNA m6A levels were explored. We performed functional characterization in A549 and H1734 cells lines to elucidate the molecular role of RBM15. Results found that RBM15 was up-regulated in the LUAD tissue and cells, which was linked to poor survival of LUAD patients. RBM15 can be knocked down via siRNA in A549, which leads to the exploration of the associations between RBM15 with cell characteristics. In vivo, RBM15 knockdown could decrease the methylation level, reduce proliferation, accelerate apoptosis and inhibit tumor growth. Our research shows that RBM15 facilitates LUAC cell progression by m6A demethylation. However, it is necessary to conduct further researches on potential downstream molecular mechanisms and m6A modification of RBM15 activity in LUAC.

CDC25C as a Predictive Biomarker for Immune Checkpoint Inhibitors in Patients With Lung Adenocarcinoma.

The application of immune checkpoint inhibitors (ICIs) in non-small cell lung cancer has significantly improved patient survival. However, most patients fail to respond to ICIs or develop drug resistance during treatment. Therefore, novel biomarkers are needed to predict the efficacy of ICIs or provide clues on how to overcome drug resistance. Here, it was revealed that cell division cycle 25C (CDC25C) expression was upregulated in lung adenocarcinoma (LUAD) compared to that of normal lung tissue in multiple databases. This was further verified by q-PCR. Furthermore, higher CDC25C expression was associated with shorter overall survival and worse pathological stage. Most importantly, a higher CDC25C expression was associated with shorter progression-free survival in LUAD patients treated with nivolumab, suggesting the role of the cell cycle in immunotherapy. In addition, CDC25C expression was significantly associated with immune cell infiltration and immune-related signatures in the LUAD tumor microenvironment. Moreover, CDC25C was differentially expressed and correlated with overall survival in multiple tumors, indicating that CDC25C is a broad-spectrum biomarker. Taken together, our study demonstrates that CDC25C is a prognostic biomarker for LUAD patients, especially for patients treated with ICIs. Our study also provides strong evidence for the role of the cell cycle in ICIs therapy and tumor microenvironment.

Activation of circ_0072088/miR-1261/PIK3CA pathway accelerates lung adenocarcinoma progression.

BackgroundCircular RNAs (circRNAs) are involved in the tumorigenesis and progression of lung adenocarcinoma (LUAD). This study aimed to determine the role of circ_0072088 in LUAD.MethodsThe existence and expression of circ_0072088 in human LUAD tissues and cell lines were determined through Sanger sequencing, quantitative reverse transcription‐polymerase chain reaction, and fluorescence in situ hybridization (FISH). Subsequently, the biological role of circ_0072088 was examined using loss‐of‐function assays in H1299 cells. Moreover, circ_0072088/miR‐1261/PIK3CA pathway‐mediated biological effects in H1299 were verified using bioinformatic prediction and experiments, including interaction analysis (FISH, luciferase reporter, and RNA‐pulldown assays), and tumor biological function test (CCK8 and colony formation, wound healing, and transwell assays). Finally, miR‐1261 and PIK3CA expression and LUAD patient survival were further analyzed using FISH, immunohistochemical staining, and the Kaplan–Meier plotter database, respectively.ResultsFirst, an increase in circ_0072088 was confirmed in human LUAD tissues. Thereafter, it was mainly localized in the cytoplasm and was found to enhance cell proliferation, migration, and invasion of H1299 cells. Mechanistically, circ_0072088 directly downregulated miR‐1261 expression, whereas increased PIK3CA gene expression was associated with poor overall survival of LUAD patients. The activation of the circ_0072088/miR‐1261/PIK3CA regulatory pathway may play a significant role in the tumorigenesis and progression of LUAD.ConclusionsCirc_0072088‐dependent regulation of miR‐1261/PIK3CA is important for cell proliferation, migration, and invasion during the tumorigenesis and progression of LUAD, warranting the need to consider the circ_0072088/miR‐1261/PIK3CA regulatory pathway as a potential therapeutic target in patients with lung adenocarcinoma.

Inhibition of epidermal growth factor receptor suppresses parathyroid hormone-related protein expression in tumours and ameliorates cancer-associated cachexia.

BackgroundLung cancer is the primary cause of cancer deaths worldwide. Activation of epidermal growth factor receptor (EGFR) leads to lung cancer progression and poor prognosis while involuntary weight loss remains a major problem. Tumour‐derived parathyroid hormone‐related protein (PTHrP) emerged as a potential mediator of cachexia. Here, we investigated the modulatory role of EGFR signalling in PTHrP (encoded by Pthlh) gene expression and the impact of this relationship on cancer cachexia.MethodsGlobal gene expression profiles of Lewis lung carcinoma (LLC) cells were analysed. Pthlh mRNA levels were measured by qRT‐PCR in LLC cells treated with EGFR ligands and tyrosine kinase inhibitors (TKIs). LLC tumour‐bearing mice received EGFR TKI erlotinib for 7 days via intraperitoneal injection or oral gavage. Tumour Pthlh mRNA, weight of fat/muscle tissue, and grip strength were assessed. RNA‐seq data from The Cancer Genome Atlas and gene expression analysis tools were used to characterize expression profiles of PTHLH and EGFR along with correlation analysis of PTHLH with EGFR and transforming growth factor alpha (TGFA) in human lung cancer and head and neck squamous carcinoma (HNSC). Survival of lung squamous cell carcinoma (LUSC) and lung adenocarcinoma (LUAD) patients with EGFR gene alterations was analysed in regard to PTHLH expression.ResultsExpression of EGFR ligands, EGFR itself, and PTHrP co‐clusters in LLC cells. Activation of EGFR signalling with its ligands significantly increases (3.8‐fold, P < 0.0005) while EGFR TKIs significantly decrease (90%, P < 0.0005) Pthlh mRNA levels in LLC cells. Pthlh mRNA drops 65–75% (P < 0.0005) in tumours upon treatment of LLC tumour‐bearing mice with erlotinib while their muscle mass and grip strength increase (9.2% P < 0.05, 23% P < 0.005, respectively) compared with tumour‐bearing control mice. PTHLH is overexpressed in tumours of LUSC (45.8‐fold, P < 0.05) and HNSC (17.5‐fold, P < 0.05) compared with normal tissue. PTHLH expression correlates with EGFR and its ligand TGFA in both cancers (LUSC: n = 745, R = 0.32, P < 0.0001 and R = 0.51, P < 0.0001; HNSC: n = 545, R = 0.34, P < 0.001 and R = 0.50, P < 0.001, respectively). High PTHLH mRNA associates with poor overall survival in LUAD patients with activating EGFR mutations (n = 40, log‐rank test, P = 0.0451).ConclusionsEpidermal growth factor receptor signalling regulates expression of cachexia mediator PTHrP. EGFR inhibition reduces PTHrP expression in LLC tumours and ameliorates cachexia in LLC tumour‐bearing mice.

Inducible Co-Stimulator ICOS Expression Correlates with Immune Cell Infiltration and Can Predict Prognosis in Lung Adenocarcinoma.

BackgroundInducible co-stimulator (ICOS) is a cell-enhanced co-stimulatory receptor that has shown great potential in the regulation of innate and adaptive immunity. However, the role of ICOS in lung adenocarcinoma (LUAD) remains unclear.MethodsWe used data from the Cancer Genome Atlas(TCGA) database to identify the expression and prognostic role of ICOS in LUAD. The results were validated using Gene Expression Omnibus(GEO) and Kaplan-Meier plotter databases. A model with predictive performance for overall survival of LUAD patients was constructed using fitted ICOS expression and other clinical parameters. We explored the biological function of ICOS. Subsequently, we further analysed and validated the effect of ICOS expression on tumour immune microenvironment (TIME) and survival. Finally, the CellMiner database was used to determine the relationship between ICOS expression and drug sensitivity.ResultsICOS expression is significantly associated with poor prognosis in multiple cancers, especially LUAD, and is a good predictor of overall survival in LUAD patients. The biological function is to promote autoimmunity and inhibit cell proliferation. ICOS-related survival prediction model developed to more accurately predict 1-, 3- and 5-year survival probabilities for LUAD patients. In addition, we can use the expression of ICOS to effectively assess patient malignancy, prognosis, TIME status and clinical combination of drugs.ConclusionOur results suggest that ICOS is correlated with prognosis and immune infiltrating levels in LUAD. Higher ICOS expression predicts better TIME. This study provides a novel strategy for the development of immunotherapeutic and prognostic markers in LUAD.

Identification of a Prognostic Signature Composed of GPI, IL22RA1, CCT6A and SPOCK1 for Lung Adenocarcinoma Based on Bioinformatic Analysis of lncRNA-Mediated ceRNA Network and Sample Validation.

Lung adenocarcinoma (LUAD) is one of the most common malignant tumors with high morbidity and mortality in China and worldwide. Long non-coding RNAs (lncRNAs) as the competing endogenous RNA (ceRNA) play an essential role in the occurrence and development of LUAD. However, identifying lncRNA-related biomarkers to improve the accuracy of LUAD prognosis remains to be determined. This study downloaded RNA sequence data from The Cancer Genome Atlas (TCGA) database and identified the differential RNAs by bioinformatics. A total of 214 lncRNA, 198 miRNA and 2989 mRNA were differentially identified between LUAD and adjacent nontumor samples. According to the ceRNA hypothesis, we constructed a lncRNA-miRNA-mRNA network including 95 protein-coding mRNAs, 7 lncRNAs and 15 miRNAs, and found 24 node genes in this network were significantly associated with the overall survival of LUAD patients. Subsequently, through LASSO regression and multivariate Cox regression analyses, a four-gene prognostic signature composed of GPI, IL22RA1, CCT6A and SPOCK1 was developed based on the node genes of the lncRNA-mediated ceRNA network, demonstrating high performance in predicting the survival and chemotherapeutic responses of low- and high-risk LUAD patients. Finally, independent prognostic factors were further analyzed and combined into a well-executed nomogram that showed strong potential for clinical applications. In summary, the data from the current study suggested that the four-gene signature obtained from analysis of lncRNA-mediated ceRNA could serve as a reliable biomarker for LUAD prognosis and evaluation of chemotherapeutic response.

Construction of a Novel Ferroptosis-Related Gene Signature for Predicting Survival of Patients With Lung Adenocarcinoma.

Lung adenocarcinoma (LUAD) is the most diagnosed subtype of lung cancer; ferroptosis is widely involved in the pathological cell death associated with various cancers, including lung cancer. However, the comprehensive relationship between ferroptosis and LUAD is little known in molecular levels until now. In the present study, 513 LUAD patients could be aggregated into three clusters by consensus clustering based on RNA sequencing data of 291 ferroptosis-related genes (FRGs) in The Cancer Genome Atlas (TCGA) database; cluster2 had significant survival advantage compared to the other two clusters. A novel prognostic model of 8 differential FRGs was constructed to effectively divide LUAD patients into high- or low-risk group according to the risk scores by the Cox and LASSO regression analyses. The overall survival of LUAD patients in the high-risk group was significantly worse in the TCGA and GEO cohorts. Moreover, patients with radiation therapy or high clinical stage had obviously higher risk scores. We validated the differential mRNA and protein expression of four FRGs in paired tumor and normal samples from our clinical cohort. Our study constructed a novel FRG signature to predict the prognosis of LUAD patients, which might provide a new prognostic tool and potential therapeutic targets for LUAD.