Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305-5655, USA. mchua@stanford.edu
BACKGROUND: Hepatocellular carcinoma (HCC) is a particularly lethal cancer with few treatment options. Since gallium is known to accumulate specifically in HCC tumors but not in non-tumor liver, we investigated two gallium compounds, gallium nitrate (GaN) and gallium maltolate (GaM), as potential new agents for treating HCC. MATERIALS AND METHODS: The anti-proliferative and apoptotic activities of GaN and GaM were assessed in vitro using four HCC cell lines. HCC gene expression data was analyzed to provide a mechanistic rationale for using gallium in the treatment of HCC. RESULTS: Both compounds showed dose-dependent antiproliferative activity in all four HCC cell lines after 6-day drug exposure (IC50 values range from 60-250 microM for gallium nitrate and 25-35 microM for gallium maltolate). Gallium maltolate at 30 microM additionally induced apoptosis after 6 days. HCC gene expression data showed significantly elevated expression of the M2 subunit of ribonucleotide reductase, which is a target for the antiproliferative activity of gallium. CONCLUSION: These data support clinical testing of gallium maltolate, an orally active compound, in the treatment of HCC.