Pan-cancer multi-omics analysis to identify the potential pro-oncogenic properties of GREM1 as a promising targets for cancer prognosis and therapeutics

Abstract

We aimed to investigate the potential pro-oncogenic properties of GREM1 by Pan-cancer multi-omics analysis. Accumulating evidence has highlighted that GREM1 (Gremlin 1), serves as an inhibitor of BMP (Bone Morphogenetic Protein) family, involve in bone related diseases, carcinogenesis, cell stemness, and cell differentiation. However, the effect and underlying mechanism of GREM1 on the cancer biology remain largely elusive. The mRNA expression of GREM1 were extracted from GTEx (Genotype-Tissue Expression) and TCGA (The Cancer Genome Atlas) database. Analysis of OS (Overall Survival), PFI (Progression Free Interval), DSS (Disease-Specific Survival), and ROC (Receiver Operating Characteristic) were performed to predicted prognostic value of GREM1 in various cancers. The TIMER (Tumor Immune Estimation Resource) online tool was used to investigate the relationship between GREM1 transcriptional level and infiltration of immune cells. KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis and GO (Gene Ontology) analysis were used to investigate the GREM1 related molecular events, and then constructed a PPI (Protein-Protein Interaction) network via the STRING (Search Tool for the Retrieval of Interaction Genes/Proteins) online tool. Western blot was performed to investigate the indicated protein expression. In the present study, our results showed that GREM1 tended to be upregulated in various cancers, which would correlate with the poor prognosis. Mechanistically, our results showed that GREM1 involve in regulating the ECM-receptor interaction pathway, upregulation of MMP activity, angiogenesis, and immune cell infiltration. In vitro studies, our results further showed that BMP agonist significantly decreased the protein level of GREM1 in GES-1 cells and BGC cells, which accompanied by inhibiting migration and proliferation in GES-1 cells and BGC cells. BMP inhibitor significantly promoted GREM1 expression and migration in BGC cells, but not GES-1 cells. GREM1 might serve as a potential and promising prognostic biomarker for drug development and cancer treatment.

Keywords: Gremlin 1; migration; pan-cancer; prognosis; proliferation.

Figure 1

The expression of GREM1 in various cancers. (a) The mRNA expression of GREM1 in 33 cancers in TCGA_GTEx samples. (b) mRNA expression of GREM1 in BLCA. (c) mRNA expression of GREM1 in LUAD. (d) mRNA expression of GREM1 in LUSC. (e) mRNA expression of GREM1 in HNSC. (f) mRNA expression of GREM1 in COAD. (g) mRNA expression of GREM1 in BRCA. (h) mRNA expression of GREM1 in STAD. (i) Protein expression of GREM1 in STAD and LUAD.

Figure 2.

Relationship between GREM1 expression and the prognosis. (a) Analyzing the relationship between GREM1 expression and OS using a forest plot in the indicated cancers. (b–j) Analyzing the relationship between GREM1 expression and OS using survival plots in the indicated cancers. (k) Analyzing the relationship between GREM1 expression and DSS using a forest plot in the indicated cancers. (l) Analyzing the relationship between GREM1 expression and PFI using a forest plot in the indicated cancers.

Figure 3.

The correlation of GREM1 expression and tumor immune infiltration. (a–e) Heatmaps of correlations between GREM1 expression and B cells, T cell CD4+, T cell CD8+, macrophage, and monocyte in TIMER2 database, respectively.

Figure 4.

Functional enrichment analysis and protein interaction analysis of GREM1 target genes. (a) GO/KEGG analysis of GREM1 targeted genes. (b) Significance of GO/KEGG analysis of GREM1 targeted genes. (c) Protein-protein interaction networks of GREM1 targeted genes. (d–i) The correlation analysis of GREM1 and CALD1, ACTN1, SYNPO2, CNN1, MYH11, VCL, respectively.

Figure 5.

Expression of GREM1 in gastric cancer. (a) The effect of BMP agonist or inhibitor on regulating GREM1 protein level in GES-1 cells, β-ACTIN was using as loading control. (b) The effect of BMP agonist or inhibitor on regulating GREM1 protein level in BGC cells, β-ACTIN was using as loading control. (c) The effect of BMP agonist or inhibitor on wound healing in GES-1 cells. (d) The effect of BMP agonist or inhibitor on wound healing in BGC cells. (e) Quantification of wound healing percentage from (c). (f) Quantification of wound healing percentage from (d). (g) Cell-Counting-Kit-8 assay to analyze the effect of BMP agonist or inhibitor on proliferation of GES-1 cells. (h) Cell-Counting-Kit-8 assay to analyze the effect of BMP agonist or inhibitor on proliferation of BGC cells.