IGFBP7 promotes gastric cancer by facilitating epithelial-mesenchymal transition of gastric cells

Abstract

Gastric cancer (GC) with high morbidity and mortality is one major cause of tumor-related death. Mechanisms underlying GC invasion and metastasis remain unclear. IGFBP7 exerted variable effects in different cancers and its role in GC is controversial. Here, IGFBP7 was found to be upregulated and elevated IGFBP7 expression represented a poorer overall survival in GC using bioinformatics analysis. Moreover, IGFBP7 was up-regulated in human GC specimens and promoted tumor growth in xenograft tumor animals. For GC cell lines, we found that IGFBP7 was also upregulated and facilitated the cell malignant behavior and EMT of GC cells, which may involve NF-κB and ERK signaling pathways. This research may provide new avenues for GC therapy.

Keywords: EMT; Gastric cancer; IGFBP7; Invasion; Migration.

Fig. 1

IGFBP7 is upregulated and indicates poor prognosis in GC. (A) Bioinformatic analysis of IGFBP7 expression and (B) its association with overall survival in GC. (C) Representative western blots of IGFBP7 in human GC specimens (the full, non-adjusted images of western blots was showed in S-Fig. 1C as supplementary material). (D) Quantitative analysis of the IGFBP7/β-actin ratio. (E, F) IGFBP7 expression levels in GC cell lines (the full, non-adjusted images of western blots was showed in S-Fig. 1F as supplementary material). **p < 0.01, ***p < 0.001, ****p < 0.0001.

Fig. 2

IGPBP7 promotes xenograft tumor growth in mice. (A) Photographs of the tumors of mock, sh-IGFBP7 and ov-IGFBP7 cells. (B) Growth rate of size of the xenograft tumors. (C, D) Measurements of tumor weight and volume. **p < 0.01. Sh-IGFBP7, IGFBP7 knockdown; ov-IGFBP7, IGFBP7 overexpression.

Fig. 3

IGFBP7 suppresses apoptosis and promotes proliferation of GC cells. (A, C) Cell cycle distribution in IGFBP7-knockdown and overexpressed GC cells. (B, D) Flow cytometry and statistic results of apoptosis in IGFBP7-knockdown and overexpressed GC cells. (E) Effects of IGFBP7 knockdown and overexpression on cell viability. **p < 0.01. ##p < 0.01. CC, normal control; sh-NC, negative control for IGFBP7 knockdown; ov-NC, negative control for IGFBP7 overexpression.

Fig. 4

IGFBP7 enhances GC cell migration and invasion. (A, C) Wound healing assay and quantitative analysis of wound healing ratio. (B, D, E) Transwell assay of migration and invasion cells. **p < 0.01. ##p < 0.01.

Fig. 5

IGFBP7 promotes EMT and activates NF-κB and ERK1/2 pathways in GC cells. (A) EMT-related proteins were analyzed by western blots. (B) Western blots analysis of p65, ERK1/2, p-ERK1/2 and p-p65. The full, non-adjusted images of western blots was showed inS-Fig 5A and S-Fig. 5B as supplementary material. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. ##p < 0.01, ###p < 0.001, ####p < 0.0001.