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

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.