The
epithelial cell-adhesion molecule (
EpCAM) is hyperglycosylated in
carcinoma tissue and the oncogenic function of
EpCAM primarily depends on the degree of glycosylation. Inhibiting
EpCAM glycosylation is expected to have an inhibitory effect on
cancer. We analyzed the relationship of BAP31 with 84 kinds of
tumor-associated
antigens and found that BAP31 is positively correlated with the
protein level of
EpCAM. Triple mutations of
EpCAM N76/111/198A, which are no longer modified by glycosylation, were constructed to determine whether BAP31 has an effect on the glycosylation of
EpCAM. Plasmids containing different C-termini of BAP31 were constructed to identify the regions of BAP31 that affects
EpCAM glycosylation.
Antibodies against BAP31 (165-205) were screened from a human phage
single-domain antibody library and the effect of the antibody (VH-F12) on
EpCAM glycosylation and anticancer was investigated. BAP31 increases
protein levels of
EpCAM by promoting its glycosylation. The
amino acid region from 165 to 205 in BAP31 plays an important role in regulating the glycosylation of
EpCAM. The antibody VH-F12 significantly inhibited glycosylation of
EpCAM which, subsequently, reduced the adhesion of
gastric cancer cells, inducing cytotoxic autophagy, inhibiting the AKT-PI3K-mTOR signaling pathway, and, finally, resulting in proliferation inhibition both in vitro and in vivo. Finally, we clarified that BAP31 plays a key role in promoting N-glycosylation of
EpCAM by affecting the
Sec61 translocation channels. Altogether, these data implied that BAP31 regulates the N-glycosylation of
EpCAM and may represent a potential therapeutic target for
cancer therapy.