effect of l1-orf2 on senescence of ges-1 cells and its molecular mechanisms

Objective 　To investigate the effect of long interspersed nuclear elements 1 open reading frame 2(L1-ORF2) gene on the senescence of GES-1 cells and its mechanism of molecular regulation. Methods 　Cell culture of high glucose was used to construct stable model of senescent GES-1 cells. L1-ORF2 siRNA vector was constructed and then transfected into normal GES1 and senescent ones with liposome transfection reagents for transient expression. Forty eight hours after transfection, cell growth curves were drawn to show the speed of cell proliferation, flow cytometry was used to analyze the cell cycle, β-galactosidase staining to detect cell aging and Western blotting to detect the expressions of L1-ORF2, P53 and P21proteins. Results 　Senescent GES-1 cell model and L1-ORF2 siRNA vector were constructed. Compared with negative control group, the L1-ORF2 expression decreased in normal and senescent GES-1 cells transfected with L1-ORF2 siRNA vector. There was a faster proliferation of senescent GES1 cells (P<0.05) and lower ratio of β-galactosidase (56% vs 69%, P<0.05) and G0/G1 phase (34.2% vs 39.3%, P<0.05) in senescent GES-1 cells transfected with L1-ORE2 siRNA vector than those transfected with negative control vector, while there was no obvious difference between normal GES-1 cells transfected with L1-ORF2 siRNA vector and negative control vector (P＞0.05). P53 protein was expressed only in senescent GES-1 cell, while P21 protein was expressed in both normal and senescent GES-1 cells, and the latter had a higher expression level (P<0.05). The GES-1 cells transfected with L1-ORF2 siRNA vector showed lower expressions of P53 and P21 proteins than those transfected with negative control vector (P<0.05). Conclusions 　L1-ORF2-siRNA vector could down-regulate the expression of L1-ORF2 protein in normal and senescent GES-1 cells and promote the proliferation of senescent GES-1 cells. P21 and P53 proteins participate in the process of L1-ORF2 regulating cellular senescence. DOI: 10.11855/j.issn.0577-7402.2016.06.09