The prognostic significance and Immunomodulatory role of SCGB3A1 expression in stage I lung adenocarcinoma

Abstract

Background: Many early-stage lung adenocarcinoma patients experience recurrence or metastasis after surgery, and the efficacy of targeted therapies remains suboptimal, significantly impacting the prognosis of these patients. Our study aims to investigate the impact of SCGB3A1 on the prognosis of lung adenocarcinoma patients and its role in immunity. We propose that SCGB3A1 may offer a novel treatment approach for lung adenocarcinoma patients who do not respond well to targeted therapies.

Methods: We obtained RNA sequencing data from 539 lung adenocarcinoma samples, 59 normal tissues, and 2 metastatic cancer tissues from The Cancer Genome Atlas database. Using Venn diagrams, we analyzed the expression of SCGB3A1 and other differentially expressed genes (DEGs) in different patient groups. Additionally, we performed another Venn diagram analysis to explore the association between SCGB3A1 and immune-related genes. We investigated the relationship between SCGB3A1 expression and patient clinical-pathological data and prognosis. Furthermore, through GO, KEGG, and GSEA enrichment analyses, we explored the functional roles of SCGB3A1 and its association with immune cell infiltration and immune checkpoint genes. The role of SCGB3A1 in LUAD was investigated by cytological experiments.

Results: The results indicated that SCGB3A1 is associated with both prognosis and immunity. In lung adenocarcinoma, SCGB3A1 may function as a tumor suppressor gene. The high-expression group of SCGB3A1 exhibited a better prognosis and more pronounced immune cell infiltration. Additionally, SCGB3A1 was associated with smoking status and tumor size. A multivariate Cox regression model suggested that SCGB3A1 expression, pathological type, and ethnicity independently impact patient prognosis. Functional enrichment analysis indicated that SCGB3A1 was related to tumor progression, cell proliferation, and immune suppression. Furthermore, ssGSEA analysis revealed that SCGB3A1 expression is associated with immune cell infiltration and tumor-related immune genes. Experimental validation suggested that the overexpression of SCGB3A1 suppressed cell proliferation, migration, and invasion of LUAD.

Conclusions: In summary, this study investigated the association between SCGB3A1 and the prognosis of early-stage lung adenocarcinoma. The findings revealed that SCGB3A1 is related to immune cell infiltration and tumor-related immune gene expression, which may provide insights into the role of SCGB3A1 in immunotherapy. The cytological experiments indicate that SCGB3A1 is a potential therapeutic target for LUAD.

Keywords: Immune infiltration; Lung adenocarcinoma; Prognostic biomarker; SCGB3A1; Stage I.

Fig. 1

Identification of DEG and its co-expressed genes. Distribution of DEGs of LUAD and identification of DEGs association with prognosis and immunity of LUAD patients. Volcano plot of 1552 differentially expressed genes in lung adenocarcinoma verses normal tissue (a) and 302 in stage I LUAD verses stage II/III/IV LUAD (b). Upregulated genes are red, while downregulated genes are blue. Venn diagram (c) of overlapping target genes between DEGs observed in two groups. Venn diagram (d) of overlapping genes between Fig. 1c and immune-related genes. A heat map (e) of SCGB3A1 and its co-expressed genes.Red/blue dots: DEGs meeting|log₂FC| >2 and FDR < 0.05

Fig. 2

The expression level of SCGB3A1 in different groups. SCGB3A1 is downregulated in LUAD tumors, with stage-dependent expression (a). Overall survival were better in subgroup of high SCGB3A1 expression in stage I LUAD patients (b).In validation cohort, the high SCGB3A1 expression had lower mortality (c)

Fig. 3

The relationship between the expression of SCGB3A1 and smoking. Among smokers (a) and non-smokers (b), high SCGB3A1 expression was always associated with better overall survival, although the P value did not reach statistical significance in non-smokers subgroup (P = 0.12)

Fig. 4

GO, KEGG and GSEA analysis about SCGB3A1 expression. GO analysis revealed 30 immune-related functions associated with SCGB3A1 (a), comprising MF, CC and BP. 18 KEGG pathway was related to DEGs with similar expression trends (b). Among these, Neutrophil extracellular trap formation, viral carcinogenesis, necroptosis, ATP-dependent chromatin remodeling, and transcriptional misregulation in cancer were positively associated with SCGB3A1. Conversely, SCGB3A1 exhibits negative correlations with gastric cancer, calcium signaling pathways, and MAPK signal transduction. GSEA analysis revealed two signaling pathways (c and d) enriched in stage I lung adenocarcinoma patients with high SCGB3A1 expression

Fig. 5

The relationship between SCGB3A1 expression and tumor immunity. In the bar graph (a), SCGB3A1 expression was correlated with 20 immune cells. The horizontal axis represents correlations, and the vertical axis represents immune cells. SCGB3A1 expression was positively correlated with Mast cell (b), Eosinophil (c), T follicular helper cell (d), Activated B cell (e), Immature dendritic cell (f), Monocyte (g), Central memory CD4 T cell (h), and was negatively correlated with Activated CD4 T cell (i)

Fig. 6

The relationship between SCGB3A1 expression and immune cells. The relationship between SCGB3A1 expression and immune cells. Compared to low expression of SCGB3A1, the high expression group of stage I LUAD had greater concentrations of Mast cell (a), Eosinophil (b), T follicular helper cell (c), Activated B cell (d), Immature dendritic cell (e), Monocyte (f), Central memory CD4 T cell (g), and was negatively correlated with Activated CD4 T cell (h)

Fig. 7

The relationship between SCGB3A1 expression and immune-related genes. The bar graph show association between SCGB3A1 expression in stage I LUAD and 20 immune-related genes. HHLA2, CD40LG, TNFRSF14, CD27, VTCN1 and CD44 had similar expression trends with SCGB3A1

Fig. 8

Overexpression SCGB3A1 inhibits the proliferation of LUAD in vitro experiments. qRT-PCR confirms that SCGB3A1 expression increases after overexpression. (b) SCGB3A1 IHC staining in LUAD tissues and normal tissues (c) Plate cloning indicates significant inhibition of clone formation ability after overexpressing SCGB3A1. (d) The CCK8 proliferation experiment showed that overexpression of SCGB3A1 would inhibit the proliferation of LUAD. (e)The mobility of A549 and H1299 cells was measured by a wound-healing assay. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001