Summary： Poly （ADP-ribose） polymerase-1 （PARP-1） inhibitors and histone deacetylase （HDAC） in- hibitors have recently emerged as promising anticancer drugs. The aim of this study was to investigate the effect of combination treatment with the PARP inhibitor P J34 and HDAC inhibitor SAHA on the proliferation of liver cancer cells. Cell proliferation and apoptosis were assessed in three human liver cancer cell lines （HepG2, Hep3B and HCC-LM3） treated with PJ34 （8 μmol/L） and SAHA （1 panol/L）, alone or combined, by Cell Counting Kit-8 assay and flow cytometry, respectively. The nude mice bear- ing subcutaneous HepG2 tumors were administered different groups of drugs （10 mg/kg PJ34, 25 mg/kg SAHA, 10 mg/kg PJ34＋25 mg/kg SAHA）, and the inhibition rates of tumor growth were compared between groups. The results showed that combined use of P J34 and SAHA could synergistically inhibit the proliferation of liver cancer cell lines HepG2, Hep3B and HCC-LM3. The apoptosis rate of HepG2 cells treated with PJ34＋SAHA was significantly higher than that of HepG2 cells treated with PJ34 or SAHA alone （P〈0.05）. In vivo, the tumor inhibition rates were 53.5%, 61.4% and 82.6% in PJ34, SAHA and PJ34＋SAHA groups, respectively. The combined use of PJ34 and SAHA could significantly inhibit the xenograft tumor growth when compared with use of P J34 or SAHA alone （P〈0.05）. It was led to conclude that P J34 and SAHA can synergistically suppress the proliferation of liver cancer cells.
