Downregulation of GNA14 in Hepatocellular Carcinoma Indicates an Unfavorable Prognosis
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ONCOLOGY LETTERS 20: 165-172, 2020 Downregulation of GNA14 in hepatocellular carcinoma indicates an unfavorable prognosis TAO YU1*, SIYU LU2* and WENJING XIE2 Departments of 1Medical Oncology and 2Anesthesiology, Xuzhou Municipal Hospital Affiliated to Xuzhou Medical University, Xuzhou, Jiangsu 221000, P.R. China Received August 2, 2019; Accepted March 5, 2020 DOI: 10.3892/ol.2020.11538 Abstract. Guanine nucleotide-binding protein subunit α14 In conclusion, low GNA14 expression may be a novel biomarker (GNA14) knockdown was demonstrated to inhibit the prolifera- for diagnosis and prognosis prediction for patients with HCC. tion of endometrial carcinoma cells in a recent study; however, its role in hepatocellular carcinoma (HCC) is unknown. In Introduction the present study, the clinical significance of GNA14 in HCC was assessed using a dataset of patients with HCC from The Liver cancer was the second leading cause of cancer-asso- Cancer Genome Atlas database. The Integrative Molecular ciated mortality worldwide in 2015 (1). Patients with HCC Database of Hepatocellular Carcinoma and Oncomine data- have no noticeable symptoms, making an accurate diagnosis bases were also used to identify the expression levels of GNA14 challenging; therefore, effective and efficient treatment of in HCC tissues. The association between GNA14 expression HCC should be available at a much earlier stage, and novel levels and clinicopathological features was assessed using the biomarkers are required to improve earlier diagnosis of HCC Wilcoxon signed-rank test and logistic regression analysis. and guide clinical management (2,3). Kaplan-Meier curves and Cox regression analysis were applied HCC is associated with increased expression levels of to evaluate the independent risk factors for clinical outcomes. α-fetoprotein (AFP) (4). AFP is a serum glycoprotein that has The present study determined GNA14 DNA methylation levels been widely used as a conventional biomarker for HCC (5). and tumor‑infiltrating immune cells, as well as used Gene Set However, the expression levels of AFP remain normal in >30% Enrichment Analysis (GSEA) in HCC. GNA14 mRNA expres- of patients with HCC at the time of diagnosis. In addition, sion levels were lower in HCC compared with normal tissues. relatively low AFP expression levels have been identified in Downregulation of GNA14 in HCC was significantly associated approximately 30% of HCC (5). Although AFP is often used with tumor grade, clinical stage and T stage. Furthermore, low in combination with ultrasound for an accurate diagnosis of expression of GNA14 was an independent predictor for survival HCC, novel biomarkers may improve the diagnostic accuracy outcomes. GNA14 expression levels were partially correlated and detection rates (6,7). with the infiltration of B cells and macrophages. Additionally, Guanine nucleotide-binding protein subunit α (GNA) GSEA analysis revealed that the expression levels of GNA14 is a member of the guanine nucleotide-binding (G protein) were associated with multiple signaling pathways, such as family that serve as modulators or transducers in miscel- translation, DNA replication, and homologous recombination. laneous transmembrane signaling systems (8,9). Mutations in G protein subunits α14 (GNA14), αQ (GNAQ) and α11, are involved in ~50% of cherry hemangiomas and cherry-like hemangiomas, and pathological and molecular studies have demonstrated common functions of GNA14 mutations in Correspondence to: Dr Wenjing Xie, Department of vascular neoplasms (10). In addition, GNA14 silencing has Anesthesiology, Xuzhou Municipal Hospital Affiliated to been demonstrated to impair the proliferation of endometrial Xuzhou Medical University, 9 Zhongshan North Road, Xuzhou, carcinoma cells by enhancing apoptosis and inducing cell Jiangsu 221000, P.R. China cycle arrest (11). Additionally, somatic activating mutations in E-mail: [email protected] GNA14 induce the activation of the MAPK signaling pathway Abbreviations: HCC, hepatocellular carcinoma; TCGA, The and contribute to the occurrence and development of congen- Cancer Genome Atlas; GNA14, guanine nucleotide-binding protein ital and sporadic vascular tumors, providing novel insight into subunit α14; TIICs, tumor-infiltrating immune cells the underlying mechanisms of carcinogenesis (12). The present study investigated the prognostic value of *Contributed equally GNA14 expression levels in HCC according using data from The Cancer Genome Atlas (TCGA). Additionally, biological Key words: GNA14, HCC, prognostic marker, TCGA processes and signaling pathways associated with GNA14 that may be involved in the molecular pathogenesis of HCC were identified based on the Gene Set Enrichment Analysis (GSEA) 166 YU et al: GNA14 AND HEPATOCELLULAR CARCINOMA analysis. Overall, the present study aimed to explore the role Table I. The clinicopathological characteristics of 377 patients of GNA14 in HCC. with hepatocellular carcinoma. Materials and methods Characteristic n % Data sources. RNA‑sequencing (RNA‑seq) data (workflow Age at diagnosis, years (range) 61 (16-81) type, htseq-counts) and matching clinical data of 377 patients Sex were obtained from the Genomic Data Commons data Female 122 32.4 portal (https://portal.gdc.cancer.gov/) in June 2019, including Male 255 67.6 information from TCGA database and the Therapeutically Grade Applicable Research to Generate Effective Treatments G1 39 15.4 program. The clinicopathological characteristics included age, G2 124 49.0 sex, histological grade, clinical stage, T, N and M staging (13). G3 82 32.4 According to a previous study (14), the processing of data and G4 8 3.2 further analysis were conducted to explore the associations Clinical stage between GNA14 expression levels and clinicopathological I 125 51.9 characteristics in HCC. An unpaired t-test was performed to II 60 24.9 analyze the difference between tumor and normal samples. III 55 22.8 IV 1 0.4 Integrative Molecular Database of Hepatocellular Carcinoma (HCCDB) analysis. The HCCDB (http://lifeome. T stage net/database/hccdb/) (15) is an integrated molecular database T1 128 50.4 of HCC with 15 HCC gene expression datasets including T2 65 25.6 3,917 samples. The HCCDB includes 13 datasets from the T3 54 21.3 Gene Expression Omnibus database and 2 RNA-seq datasets T4 7 2.8 from TCGA liver hepatocellular carcinoma (LIHC) and the N stage International Cancer Genome Consortium (ICGC) databases N0 177 69.7 to explore the expression levels of GNA14 mRNA in HCC. N1 1 0.4 Nx 76 29.9 Oncomine database analysis. Oncomine is a cancer micro- M stage array database (oncomine.org/) containing 715 datasets and M0 186 72.9 86,733 cancer samples (16). In the present study, Oncomine was M1 1 0.4 used to further assess the expression levels of GNA14 in HCC and Mx 68 26.7 adjacent normal tissue. The parameters were set as fold-change ≥2 and P<0.05, and the top 10% of ranked genes were exhibited. DNA methylation level of GNA14. The DNA methylation levels Statistical analysis. Statistical analysis was performed using of GNA14 were analyzed using the Methylation in Human R software version 3.6.0 (http://www.R-project.org/) (20), Cancer database (MethHC) (methhc.mbc.nctu.edu.tw/) (17), R studio software version 1.2.5019 (21) and GraphPad a comprehensive database of DNA methylation and gene Prism version 8.0 software (GraphPad Software, Inc.) for expression in human cancer. Unpaired t-tests were performed data processing and analysis. All data were represented as to analyze the difference between tumor and normal samples. mean ± standard deviation (SD). According to the median value of GNA14 expression levels in HCC tissues, patients were Tumor Immune Estimation Resource (TIMER) database divided into low and high GNA14 expression groups. Survival analysis. A systematic assessment of the correlation between analysis was conducted by the Kaplan-Meier method. Wilcoxon different immune cells, such as B cells, CD4+ T cells, CD8+ signed-rank test and log regression were used to analyze the T cells, neutrophils, macrophages, and dendritic cells, and association of clinicopathological characteristics and GNA14 GNA14 expression levels across different types of cancer expression levels. The univariate and multivariate Cox propor- were performed using the TIMER database (https://cistrome. tional hazards model was performed to evaluate the prognostic shinyapps.io/timer/) (18). value of GNA14 expression. Receiver operating characteristic (ROC) curves were constructed using log-rank tests to evaluate GSEA. Gene set enrichment analysis (GSEA) was conducted the diagnostic value of GNA14 expression in HCC. P<0.05 was using c2.cp.kegg.v6.0.symbols.gmt as a reference gene set considered to indicate a statistically significant difference. (software.broadinstitute.org/gsea/) (19). A list of genes was obtained from GSEA to account for the survival differences Results in patients with differential expression levels of GNA14. Gene set permutations were analyzed 1,000 times. In addition, Patient characteristics. Clinical and RNA-seq data of the normalized enrichment score, normalized P-value and 377 patients with primary HCC, including 377 HCC and 50 false discovery rate (FDR) q value were applied to filter the adjacent normal tissues, were obtained from TCGA database correlative pathways. and are listed in Table I. Of the 377 patients, 122 (32.4%) ONCOLOGY LETTERS 20: 165-172, 2020 167 Figure 1. Differential expressions of GNA14 evaluated using the TIMER, HCCDB and Oncomine databases for HCC. (A)