Cyclophosphamide-induced apoptosis in A431 cells is inhibited by fucosyltransferase IV

Abstract

Fucosyltransferase IV (FUT4) is an essential enzyme that catalyzes the synthesis of difucosylated oligosaccharide LeY which is overexpressed in the cancers derived from the epithelial tissues. Our previous studies have shown that FUT4 overexpression promotes A431 cell proliferation through the MAPK and PI3K/Akt signaling pathways, but the relationship between FUT4 and apoptosis remained unclear. Here, we investigated the effect of FUT4 overexpression on cyclophosphamide (CPA)-induced apoptosis in A431 cells. Western blot analysis showed that FUT4 overexpression decreased expression of Bax, Caspase 3, and PARP proteins, and increased anti-apoptotic Bcl-2 protein in A431 cells. The anti-apoptosis effect of FUT4 was confirmed both by Annexin-V/PI and JC-1 assays. The results showed that FUT4 overexpression up-regulated phosphorylation of ERK1/2 and Akt which was inhibited by CPA in dose-dependent manner. By blocking the ERK/MAPK and PI3K/Akt pathways with specific inhibitors, we demonstrated that these two pathways were required in mediating the anti-apoptosis effect of FUT4. We concluded that FUT4 inhibited cell apoptosis induced by CPA through decreasing the expression of apoptotic proteins Bax, Caspase 3, and PARP and increasing the expression of anti-apoptotic protein Bcl-2 via the ERK/MAPK and PI3K/Akt signaling pathways in A431 cells.