The Effect Of AAV2 Rep78 On The Expression Of Apoptosis Factors And Signal Transducation In HepG2 Cells

AIM: To investigate the effect of AAV2 rep78 gene on apoptosis and expression of apoptosis factors in rep78 gene-transfected HepG2 cells.METHODS: The AAV2 rep78 gene eukaryon expression vector pCI/neo- rep78 was transiently transfected into HepG2 cells by lipid-media transfection. Untransfected HepG2 cells and HepG2 cells transfected with pCI/neo were used as controls. Expression of AAV2 rep78 gene in HepG2 cells was identified by RT-PCR. MTT and TUNEL were employed to measure proliferation and apoptosis of cells in three groups. Semi-quantified RT-PCR was used to evaluate the expression level of Fas/FasL, Bax/Bcl-xL, c-myc in each group.RESULTS: AAV2 rep78 gene was transfected into HepG2 cells successfully. RT-PCR showed that AAV2 rep78 gene was only expressed in HepG2/pCI/neo- rep78 cells, but not expressed in HepG2 and HepG2/ pCI/neo cells. Analyzed by MTT, cell proliferation capacity was obviously lower in HepG2/pCI/neo-rep78 cells than in HepG2 and HepG2/pCI/neo cells (P<0.01). Analyzed by TUNEL, the rate of cell apoptosis was higher in HepG2/pCI/neo-rep78 cells(960/2000) than HepG2 (480/2000), HepG2/pCI/neo cells (550/2000) (P<0.01). Evaluated by semi-quantified RT-PCR, the expression level of Fas/FasL was significantly higher in HepG2 cells transfected with AAV2 rep78 gene than in HepG2 and HepG2/pCI/neo cells (P<0.01). Bax/Bcl-xL expression level was also elevated in HepG2/ pCI/neo- rep78 cells (P<0.01). Expression of c-myc was markedly higher in HepG2/ pCI/neo rep78 cells than in HepG2 and HepG2/pCI/neo cells(P<0.01).CONCLUSION: AAV2 rep78 gene can inhabit cell proliferation capacity,increase cell apoptosis, and up-regulate expression of apoptosis factors. The effect of AAV2 rep78 gene on the expression of apoptosis factors may be a possible mechanism responsible for the change in cell apoptosis and proliferation.