Heterodimeric interaction between GKN2 and TFF1 entails synergistic antiproliferative and pro-apoptotic effects on gastric cancer cells

Abstract

Background GKN2 and TFF1 form a heterodimer that is only generated in the mucus-secreting cells of the normal stomach. The formation of this heterodimer is frequently disrupted in gastric cancer. However, the precise roles of GKN2 alone and in the heterodimer with TFF1 as well as the contributions of GKN2 and the heterodimer to gastric carcinogenesis are poorly understood. Methods Cell viability, proliferation, and apoptosis were analyzed in AGS, MKN1, MKN28, and MKN45 gastric cancer cells transfected with GKN2 and/or TFF1 using MTT, BrdU incorporation, and apoptosis assays, respectively. In addition, cell viability was examined in HFE-145 non-neoplastic gastric epithelial cells after GKN2 and/or TFF1 silencing. Furthermore, the cell cycle and the expression of cell cycle and apoptosis related proteins were assessed. The interaction between GKN2 and TFF1 was confirmed by co-immunoprecipitation. Immunohisto-chemistry was employed to explore TFF1 expression in 169 gastric cancer tissues. Results Co-transfection with GKN2 and TFF1 significantly inhibited cell viability and proliferation by inducing G1/S cell cycle arrest and suppressing positive cell cycle regulators. Simultaneous knockdown of GKN2 and TFF1 in HFE-145 cells resulted in markedly increased cell viability. Moreover, the interaction of GKN2 and TFF1 promoted cell death by enhancing caspase-3/7 activity and upregulating pro-apoptotic proteins. At the mRNA level, GKN2 and TFF1 were found to be positively correlated in non-tumor and tumor samples. Immunohistochemistry revealed loss of TFF1 expression in 128 (75.73%) of 169 gastric cancers. There was a borderline-significant association between GKN2 and TFF1 protein expression in gastric cancers (P = 0.0598). Conclusion Collectively, our data demonstrated that the interaction between GKN2 and TFF1 can have synergistic antiproliferative and pro-apoptotic effects on gastric cancer.

Multiscale network analysis reveals molecular mechanisms and key regulators of the tumor microenvironment in gastric cancer

“…30 Heterodimeric interaction between GKN2 and TFF1 has synergistic antiproliferative and proapoptotic effects in GC. 19 In our study, in vitro overexpression of GKN2 in GC cells silences PTEN/PI3K/AKT/mTOR and JAK/STAT pathway, and inhibits GC proliferation and invasion as previously reported. Interestingly, overexpression of GKN2 alone recovered expression of its heterodimeric interaction partner, TFF1 to confer antitumor effects.…”

“…GKN1 is known to play an important role in the progression of gastric cancers via inhibition of EMT and cancer cell migration and TFF2 forms heteromer with MUC6 , which assembles and stabilizes the laminated structure of gastric mucus and has antibiotic activity against Helicobacter pylori . Heterodimeric interaction between GKN2 and TFF1 has synergistic antiproliferative and proapoptotic effects in GC …”

“…2a,b), known synergistic heterodimeric interaction partner of GKN2 conferring antiproliferative and proapoptotic effects on gastric cancer cells. 19 This suggests GKN2 alone is capable of conferring antitumor effect.…”

“…The TFF1-TFF2-GKN1-GKN2 axis exerts pressures on GC tumorigenesis via gastric mucosal defense 30 silencing oncogenic PTEN/PI3K/AKT/mTOR 31 JAK/STAT pathway 32 ERK1/2 axes 33 and eventually inhibits GC proliferation and invasion. 19,32 GKN1 is known to play an important role in the progression of gastric cancers via inhibition of EMT and cancer cell migration 34 and TFF2 forms heteromer with MUC6, which assembles and stabilizes the laminated structure of gastric mucus and has antibiotic activity against Helicobacter pylori. 30 Heterodimeric interaction between GKN2 and TFF1 has synergistic antiproliferative and proapoptotic effects in GC.…”

GKN2 promotes oxidative stress-induced gastric cancer cell apoptosis via the Hsc70 pathway

“…GKN2, a stomach-specific gene, has been researched upon for more than 10 years; recently, it has been proposed it acts as a tumor suppressor in many human cancer cell lines. The heterodimeric interaction between GKN2 and TFF1 played an important in inhibition of GC [29]; thereafter, its anti-proliferative and pro-apoptotic effects on GC cells were further substantiated and other mechanisms of GKN2 action emerged [30], including the recent indication that GKN2 functions as a GKN1 inhibitor, contributing to the homeostasis of gastric mucosa. GKN2 also play a significant role in regulation of gastric inflammation [31].…”