Mechanism of N-acetyl amino galactosyl transferase-14 regulating the apoptosis of glioblastoma through extracellular signal-regulated kinase 1/2 signaling pathway

Objective To study the effect of N-acetyl amino galactosyl transferase-14 (GalNAc-T14) on apoptosis of glioblastoma multiforme. Methods The U87MG cell line of glioblastoma multiforme was cultured, and the constructed pcDNA3.1-T14 plasmid was transfected into U87MG cells. The cells were divided into untreated group (control), pcDNA3.1 (+ ) empty carrier-transfected group (NC1) and pcDNA3.1-T14-transfected group (T). Real-time quantitative polymerase chain reaction (qPCR) and Western blotting were used to detect the expression of GalNAc-T14, extracellular signal-regulated kinase 1/2 (ERK1/2), inhibitor of apoptosis protein-XL (bcl-XL) and the phosphorylation level of ERK1/2. Apoptosis was detected by flow cytometry with Annexin V-fluoresceine isothiocyanate (FITC)/propidium iodide (PI) double staining. Results The relative quality of GalNAc-T14, ERK1/2 and bcl-XL was 1 before transfection, and the relative expression of GalNAc-T14 was (15 393.43±30.35) in U87MG cells. Real-time quantitative PCR showed that the relative mRNA expression of ERK1, ERK2 and bcl-XL in NC1 group was (0.98±0.12), (0.91±0.05) and (0.89±0.11) respectively, and that in T group was (0.74±0.29), (0.68±0.31) and (0.68±0.23) respectively. The expression level of ERK1/2 and anti-apoptotic protein bcl-XL in T group was lower than that in control group. Western blotting analysis showed that the gray values of ERK1/2 in control, NC1 and T groups were (85.42±3.11), (86.25±4.25), and (66.36±4.25), and those of anti-apoptotic protein bcl-XL were (82.57±3.71), (79.52±3.78), and (46.85±4.52), respectively. The percentages of early apoptosis and late apoptosis of U87MG cells was (7.74±1.23)% and (10.08±2.41)%, respectively, when high expression of GalNAc-T14 was detected by Annexin V-FITC/PI double staining, which were higher than in the control group [(1.12±0.18)%, (0.51±0.14)%] and NC1 group [(1.37±0.12)%, (0.90±0.08)%, t=3.417, P<0.05]. Conclusion GalNAc-T14 promotes apoptosis of glioblastoma cells by inhibiting the expression of ERK1/2 and bcl-XL.