Metastasis is one of the typical features of malignancy that significantly increases cancer-related mortality. Recent studies have shown that epithelial–mesenchymal transition (EMT) is closely related to the invasion and migration of cancer cells. Grainyhead-like 2 (Grhl2), a transcription factor, has been reported to be associated with several tumor processes including EMT. In the previous study, we have reported that Grhl2 functioned as a tumor suppressor in proliferation and apoptosis of gastric cancer. Here we aim to explore the effects of Grhl2 on invasion and migration of gastric cancer and further clarify its possible underlying mechanisms. As a result, in both SGC7901 and MKN45 cells, Grhl2 overexpression significantly inhibited the ability of invasion and migration. In addition, preliminary experiments showed that Grhl2 reduces the protein expression of matrix metalloproteinase-2, -7 and -9 (MMP-2, MMP-7 and MMP-9). Most importantly, Grhl2 antagonizes transforming growth factor-β (TGFβ)-induced EMT, and inhibition of TGFβ signaling pathways can restore Grhl2 expression. Finally, the results of subcutaneous xenograft model indicated that Grhl2 suppresses the growth of gastric cancer and reverses EMT process in vivo. Meanwhile, the metastatic tumor model further confirmed the inhibition of Grhl2 on metastasis of gastric cancer. Taken together, our findings proved that Grhl2, functioned as a tumor suppressor, reduces the invasion and migration through inhibition of TGFβ-induced EMT in gastric cancer.

The aim of this study was to evaluate the expression and role of Grhl2 in gastric cancer. Immunohistochemistry was performed to explore the expression of Grhl2 in gastric cancer and surrounding non-tumor tissues. Moreover, the mRNA and protein expression level of Grhl2 in human immortalized gastric epithelial cell line GES-1 and four gastric cancer cell lines (MGC803, SGC7901, MKN45, HGC27) were detected by qRT-PCR and Western blotting, respectively. To further investigate the role of Grhl2 in gastric cancer as well as the potential mechanisms, SGC7901 cells were transfected with lentiviral constructs expressing Grhl2 or empty vector, and then proliferation and apoptosis of SGC7901 cells were evaluated by MTT assay and flow cytometry, respectively. Finally, the protein expression level of c-Myc and Bcl-2 was detected by Western blotting. Both mRNA and protein expression level of Grhl2 were significantly downregulated in gastric cancer. Exogenous Grhl2 transduced into SGC7901 cells significantly inhibited the proliferation and promoted apoptosis. Meanwhile, over-expression of Grhl2 decreased c-Myc and Bcl-2 protein expression level. Taken together, our results demonstrated that Grhl2 downregulated in gastric cancer and may function as a tumor suppressor and play an important role in the development and progression of gastric cancer. These results may provide a new clue for treatment for gastric cancer.