Table 1_GADD45G as a novel prognostic biomarker and therapeutic target in glioma: integrative analysis of bulk and single-cell RNA sequencing.xlsx

BackgroundGliomas make up almost half of primary central nervous system tumors. Despite advancements in surgery and neuro-oncology, developing an effective treatment remains challenging. The protein Growth Arrest and DNA-Damage-Inducible, Gamma (GADD45G) is crucial for key cellular functions like DNA repair, genomic stability, and apoptosis. While GADD45G dysregulation has been found in various cancers, its role in glioma is still unclear.
MethodsWe analyzed unified pan-cancer datasets (TCGA, TARGET, GTEx) from UCSC Xena and integrated glioma data from CGGA and GEO (GSE108476). Prognostic value was assessed via multivariate Cox regression and Kaplan-Meier survival analysis using Gliovis. Single-cell RNA-seq data (GSE103224, GSE138794, GSE173278) were processed with Seurat (R 4.2.2), with Harmony for batch correction and UMAP for visualization. Malignant subclusters were annotated using marker genes. Functional enrichment and cell-type proportion estimation were conducted. Single-cell analysis revealed GADD45G expression patterns and identified its top correlated genes in malignant glioblastoma cells. Overexpression of GADD45G was performed to investigate its impact on cell function. Western blot analysis was used to examine the role of GADD45G in glioma cell invasion and migration.
ResultsThrough comprehensive analysis across multiple datasets, it was found that GADD45G expression is higher in glioma patients compared to normal individuals, and its expression is generally higher in lower-grade gliomas than in glioblastoma. Cox regression analysis indicated that GADD45G has a protective effect. Survival curves further demonstrated that elevated GADD45G levels are associated with improved overall survival in patients. In this study, we identified four highly heterogeneous GBM cell subpopulations using single-cell data. The MES-like cells was significantly associated with poor prognosis. Spearman correlation analysis revealed the correlation between GADD45G and VIM. Further experiments revealed that GADD45G modulates glioma cell invasion and migration, potentially through its effects on EMT-like phenotypic features.
ConclusionGADD45G expression is significantly associated with glioma outcomes and may serve as a promising biomarker for prognosis evaluation. Its involvement in regulating EMT-like phenotypic traits further highlights its therapeutic potential.

背景
神经胶质瘤约占原发性中枢神经系统肿瘤的一半。尽管外科手术与神经肿瘤学领域已取得诸多进展，但开发有效的胶质瘤治疗方案仍面临诸多挑战。生长停滞与DNA损伤诱导蛋白γ（Growth Arrest and DNA-Damage-Inducible, Gamma，GADD45G）在DNA修复、基因组稳定性及细胞凋亡等关键细胞功能中发挥至关重要的作用。尽管已有研究发现GADD45G表达失调存在于多种癌症中，但其在胶质瘤中的具体作用仍不明确。
方法
本研究从UCSC Xena数据库获取了统一的泛癌症数据集（TCGA、TARGET、GTEx），并整合了来自CGGA及GEO（GSE108476）的胶质瘤数据。通过Gliovis工具，采用多变量Cox回归分析与Kaplan-Meier生存分析评估GADD45G的预后价值。对单细胞RNA测序数据（GSE103224、GSE138794、GSE173278）采用Seurat（R 4.2.2）进行分析，使用Harmony进行批次校正，UMAP进行数据可视化。利用标记基因对恶性细胞亚群进行注释，并开展功能富集分析与细胞类型比例估算。单细胞分析揭示了GADD45G的表达模式，并鉴定出恶性胶质母细胞瘤细胞中与其表达高度相关的核心基因。通过构建GADD45G过表达体系，探究其对细胞功能的影响。采用蛋白质免疫印迹（Western blot）分析，验证GADD45G在胶质瘤细胞侵袭与迁移过程中的作用。
结果
通过多数据集综合分析，本研究发现胶质瘤患者的GADD45G表达水平显著高于正常人群，且低级别胶质瘤的GADD45G表达普遍高于胶质母细胞瘤。Cox回归分析显示，GADD45G表达发挥保护性作用。生存曲线进一步证实，GADD45G高表达与患者更长的总生存期显著相关。本研究通过单细胞数据鉴定出4个高度异质性的胶质母细胞瘤（GBM）细胞亚群，其中类间质（MES-like）细胞亚群与不良预后显著相关。Spearman相关分析揭示了GADD45G与波形蛋白（VIM）的表达相关性。后续实验发现，GADD45G可通过调控上皮间质转化（EMT）样表型特征，调节胶质瘤细胞的侵袭与迁移能力。
结论
GADD45G表达与胶质瘤患者的预后结局显著相关，有望成为胶质瘤预后评估的潜在生物标志物。其调控上皮间质转化样表型特征的作用，进一步凸显了其作为治疗靶点的潜力。