A differential proteomic study on the influence of ytterbium citrate on HepG2 cells

Objective To explore the effects of ytterbium citrate on human liver carcinoma HepG2 cell line and the potential mechanisms.Methotis The HepG2 cells were cultured with DMEM medium and divided into different groups in the following media,in serum-free medium as control,different concentration (0.01-5.00 mmol/L)[YbCit2]3-+serum-free medium as treatment group,MTT assay was used to measure the viability of the cells;2.00 mmol/L[YbCit2]3- +serum-free medium was used as treatment group,and Hoechst 33258 staining was used to detect apoptosis in HepG2 cells.Differential proteomic analysis.assay of intrueellular H2O2 levels and mitochondrial transmembrane petential were performed to study the effects of [YbCit2]3- on HepG2 cells and the potential mechanisms.Results The data showed that 72 h treatment of [YbCit2]3- at 2.00-5.00 mmol/L significantly inhibited cell proliferation,and the IC50 was(2.46±0.23) mmol/L.After treatment with 2.00 mmol/L [YbCit2]3- for 48 h and 72 h,Hoechst 33258 staining demonstrated that [YbCit2]3- induced significantly increased apoptosis in HepG2 cells.After treatment with 2.00 mmol/L[YbCit2]3- for 72 h,two dimensional gel electrophoresis and MALDI-TOF mass spectrometry analysis revealed 14 differentially expressed proteins between [YbCit2]3- -treated cells and the control cells. These proteins mainly included cofilinl, peroxiredoxin6, S100 calcium-hinding protein A6 ,and proteasome 265 non-ATPase subunit 13 isoform 3 and so on. These proteins played important roles in the processes of anti-apoptosis, oxidation reduction, cell proliferation and protein degradation. The mitochondrial membrane potential were investigated, the results showed the ted and green fluorescence ratio was 2.45 ± 0. 28 in the control group,1.56 ± 0. 23 in 24 h group,1. 16± 0. 18 in 48 h group,compared with the control, the differences were significant ( F = 23.97, P = 0. 001 ). The results of H2O2 detection showed the fluorescence intensity was 20. 00 ± 2. 08 in the control group,40. 00 ± 5.50 in 24 h group,and 48.00 ± 2. 03 in 48 h group,compared with the control, the differences were significant ( F = 48. 40, P =0. 000). The results indicated a significant reduction in mitochondrial transmembrane potential and significant increase in H2O2 generation were observed in [ YbCit2 ]3- -treated cells. Conclusion These results suggested that [ YbCit2 ] 3 - could induce apoptosis of HepG2 cells through the mechanisms involving oxidative stress and mitochondrial dysfunction. Key words: Ytterbium; Lanthanoid series elements; Cell line,tumor; Proteomics