ABSTRACT
<p><b>BACKGROUND</b>Growing preclinical evidence shows that zoledronic acid (ZOL) exhibits direct antitumor activity in various cancer cell lines. However, the cytotoxic effects of ZOL on human hepatocellular carcinoma (HCC) cells have not been established. In the present study, we investigated the effect of ZOL on HCC both in vitro and in vivo.</p><p><b>METHODS</b>Cytotoxicity and cell cycles were assessed with Sulforhodamine B colorimetric assay and flow cytometry. Expression levels of cell cycle phase-linked proteins were examined. The effect of ZOL on HCC in vivo was explored based on H22-subcutaneous injection (s.c.) and H22-intraperitoneal injection (i.p.) mice model.</p><p><b>RESULTS</b>ZOL inhibited the growth of SK-HEP-1 and H22 cells and induced S-phase arrest through downregulating cdc2 protein and upregulating cyclin A. It inhibited the growth of s.c tumors, and increased the survival of both H22-s.c. and H22-i.p. mice in vivo.</p><p><b>CONCLUSION</b>ZOL inhibits growth of HCC cells in vitro and in vivo.</p>