Loss of gastrokine-2 drives premalignant gastric inflammation and tumor progression
Trevelyan R. Menheniott, … , Louise M. Judd, Andrew S. Giraud
Trevelyan R. Menheniott, … , Louise M. Judd, Andrew S. Giraud
Published March 14, 2016
Citation Information: J Clin Invest. 2016;126(4):1383-1400. https://doi.org/10.1172/JCI82655.
View: Text | PDF
Research Article Oncology

Loss of gastrokine-2 drives premalignant gastric inflammation and tumor progression

Abstract

Chronic mucosal inflammation is associated with a greater risk of gastric cancer (GC) and, therefore, requires tight control by suppressive counter mechanisms. Gastrokine-2 (GKN2) belongs to a family of secreted proteins expressed within normal gastric mucosal cells. GKN2 expression is frequently lost during GC progression, suggesting an inhibitory role; however, a causal link remains unsubstantiated. Here, we developed Gkn2 knockout and transgenic overexpressing mice to investigate the functional impact of GKN2 loss in GC pathogenesis. In mouse models of GC, decreased GKN2 expression correlated with gastric pathology that paralleled human GC progression. At baseline, Gkn2 knockout mice exhibited defective gastric epithelial differentiation but not malignant progression. Conversely, Gkn2 knockout in the IL-11/STAT3-dependent gp130F/F GC model caused tumorigenesis of the proximal stomach. Additionally, gastric immunopathology was accelerated in Helicobacter pylori–infected Gkn2 knockout mice and was associated with augmented T helper cell type 1 (Th1) but not Th17 immunity. Heightened Th1 responses in Gkn2 knockout mice were linked to deregulated mucosal innate immunity and impaired myeloid-derived suppressor cell activation. Finally, transgenic overexpression of human gastrokines (GKNs) attenuated gastric tumor growth in gp130F/F mice. Together, these results reveal an antiinflammatory role for GKN2, provide in vivo evidence that links GKN2 loss to GC pathogenesis, and suggest GKN restoration as a strategy to restrain GC progression.

Authors

Trevelyan R. Menheniott, Louise O’Connor, Yok Teng Chionh, Jan Däbritz, Michelle Scurr, Benjamin N. Rollo, Garrett Z. Ng, Shelley Jacobs, Angelique Catubig, Bayzar Kurklu, Stephen Mercer, Toshinari Minamoto, David E. Ong, Richard L. Ferrero, James G. Fox, Timothy C. Wang, Philip Sutton, Louise M. Judd, Andrew S. Giraud

×

Figure 9

Analysis of gastric mucosal cytokines and immune cell populations in Gkn2–/– mice after 7-day H. pylori infection.

Options: View larger image (or click on image) Download as PowerPoint
Analysis of gastric mucosal cytokines and immune cell populations in Gkn...
(A) Strategy used for 7-day H. pylori SS1 infections. (B) Q-PCR analysis of H. pylori SS1 colonization levels in 7-day infected Gkn2–/– and WT stomachs (n = 7 per group). Histograms show mean colonization level (104 H. pylori genomes per 105 Gapdh copies). (C–E) Luminex array analysis of cytokine/chemokine protein levels in corpus homogenates from 7-day infected Gkn2–/– and WT (n = 7 per group) and uninfected control mice (n = 8 per group): (C) TNF-α, IL-1α, IL-6, CXCL1, and CCL4; (D) IL-10; and (E) IFN-γ. Histograms show mean normalized levels (pg cytokine/100 mg total protein). (F–H) Flow cytometry analysis of myeloid/lymphoid cells in stomachs of 7-day infected Gkn2–/– mice and uninfected controls (n = 5 per group): (F) macrophage (CD11b+F4/80+Gr1–) and DC (CD11c+); (G) Treg (CD4+CD25+Foxp3+); and (H) total MDSC, monocytic MDSC (Mo-MDSC) (CD11b+Ly6ChiLy6G–CD49d+), and granulocytic MDSC (Gr-MDSC) (CD11b+Ly6CloLy6G+CD49d–) subsets. Histograms show mean cellular prevalence (percentage of total gastric leukocytes). (I) QRT-PCR expression profiles of MDSC differentiation (Ccr2, IL4ra) and activation (S100a8, S100a9, Arg1, Arg2, Tgfb1, Tgfb2) genes in 7-day infected Gkn2–/– mice. Error bars represent mean ± SEM. P values were determined using a 2-tailed Student’s t test or 2-tailed Mann Whitney U test (I, only). Statistical significance compared with WT uninfected control mice: #P < 0.05; ##P < 0.01. Statistical significance between treatment groups: *P < 0.05; **P < 0.01; ***P < 0.001.