Objective      To study the effect of lentivirus-mediated silent information regulator 1 gene (SIRT1) on aging of hepatocellular carcinoma cells (HCCs) and its mechanism.       Methods      SIRT1 expression was targeted by lentivirus-mediated shRNA interference technology. Effect of SIRT1 on aging of HCCs was detected by RT-PCR and Western blot analysis

respectively. Proliferation of HCCs was assayed by BrdU-labeling test.  Cell cycle of HCCs was displayed by flow c

ytometry. Aging of HCCs was observed with SA-β-gal staining. Aging-related p53 and p21 proteins were demonstrated by Western blot analysis.       Results      Lentivirus-mediated shRNA significantly down-regulated the SIRT1 mRNA and protein expression levels in HCCs. SIRT1 suppressed the proliferation of HCCs with a suppression rate of 70%-80%

and significantly induced cell cycle arrest at stage G

1

. The proportion of shCont-

SIRT1- and SIRT2-infected HCCs at stage G

1

was about (42.29±0.36)%

(69.20±1.24)%

and (65.86±1.75)%

respectively. The aging-related β-galactosidase-stained HCCs were significantly greater with a positive rate of 40%-50% (P0.05)

and the aging-related p53 and p21 protein expression levels were significantly higher.       Conclusion      SIRT1 promotes the aging of HCCs possibly through the p53/p21 pathway.