Fig 2: Mechanistic diagram of the role of GREM1 in ER stress, EMT and metastasis in CRC cells.

Fig 3: CeapinA7 and GSK621 inhibit GREM1-induced CRC cellline invasion and migration. (A) The GSEA was performed using an in-house RNA-seq dataset to identify gene sets in the KEGG collections that have positive correlations with GREM1 expression. The negative regulating PERK-mediated UPR (NES = 1.6542 NP = 0.0000) and ATF6-mediated UPR signaling pathway (NES = 1.3553, NP = 0.0000) with GREM1 overexpression in HCT116 cells. (B) HCT116 pLV-GREM1 and SW480 pLV-GREM1 cells were seeded into Matrigel-coated inserts with medium containing CeapinA7 (16 µM) or GSK621 (30 µM) and incubated for 36 h, followed by the invasion assay. (C,D) Wound healing test revealed that CeapinA7 and GSK621 inhibited cell migration.

Fig 4: CeapinA7 and GSK621 reverse EMT in GREM1-overexpressing CRC cell lines. HCT116 pLV-GREM1 and SW480 pLV-GREM1 cells were exposed to CeapinA7 (6 µM,16 µM) or GSK621 (30 µM) for 24 h, respectively. After harvesting, the cells were analyzed for protein and mRNA expression. (A–D) qRT-PCR analysis revealed the expression of mRNA involved in EMT. (E,F) Western blotting analysis revealed the expression of proteins involved in the EMT.

Fig 5: GREM1 expression is correlated with poor survival in CRC patients. (A) Representative images of GREM1 in para-carcinoma and carcinoma tissues of patients with stage IV CRC. Scale bar, 250 µm. (B) Kaplan–Meier survival analysis of 597 colon cancer patients stratified by GREM1 expression levels. Kaplan–Meier survival analysis and GREM1 mRNA expression according to FPKM value 5.31 as a cutoff value in the whole cohort. p = 0.046 by log-rank (Mantel–Cox) test.