POFUT1 promotes gastric cancer progression through Notch/Wnt dual signaling pathways dependent on the parafibromin-NICD1-β-catenin complex.

Background: Aberrant glycosylation performed by glycosyltransferases is a leading cause of gastric cancer (GC). Protein O-fucosyltransferase 1 (POFUT1) expression is increased in GC specimens and cells. In this study, the biological effects and mechanisms of POFUT1 underlying the development of GC were investigated.

Methods: POFUT1 downregulated and upregulated GC cells were established. The effects of POFUT1 on cell proliferation, metastasis and apoptosis were examined using cell counting kit-8 (CCK8) assay, transwell assay, and flow cytometry. Subcutaneous xenograft tumor models were established followed by immunohistochemistry staining of resected tumors. Facilitating modulators and transcription factors were detected by western blot, immunofluorescence, luciferase reporter assay, and co-immunoprecipitation.

Results: POFUT1 played a pro-oncogenic role both in vivo and in vitro, which promoted proliferation and metastasis, as well as inhibited apoptosis in GC cells. POFUT1 promoted Cyclin D3 expression and inhibited the expression of apoptotic proteins, such as Bcl-2-associated X protein (Bax) and cleaved caspase 3, facilitating tumor growth. Moreover, POFUT1 accelerated matrix metalloproteases expression and attenuated E-cadherin expression, contributing to GC metastasis. In addition, POFUT1 expression promoted the expression and nuclear translocation of Notch1 intracellular domain (NICD1) and β-catenin and inhibited β-catenin phosphorylation degradation, accompanied by the activation of recombination signal binding protein-Jκ (RBP-J) and T-cell factor (TCF) transcription factors, respectively. It is notable that parafibromin integrated NICD1 and β-catenin, enabling the concerted activation of Wnt and Notch signaling targeted proteins.

Conclusion: These observations indicated that POFUT1 promoted GC development through activation of Notch and Wnt signaling pathways, which depended on the parafibromin-NICD1-β-catenin complex. This work provides new evidence for the further diagnosis and treatment of GC.