Curcumin regulates hepatoma cell proliferation and apoptosis through the Notch signaling pathway

Curcumin has become a compound of interest for its antioxidant and anti-neoplastic properties. This study sought to determine the effect of curcumin administration on cell proliferation and apoptosis in hepatoma cells. SMMC-7721 hepatoma cells were treated with 10, 30, or 90 μM curcumin solution, with DMEM alone (negative control), or with 20 mg/L fluorouracil (positive control). MTT colorimetry detected significant differences in the rates of cell proliferation inhibition following curcumin treatment, with increasing inhibition accompanying increasing doses of curcumin (P < 0.05), compared to the negative control. Similarly, flow cytometry revealed significant differences in the numbers of apoptotic cells following curcumin treatment: increasing doses of curcumin produced increases in the numbers of apoptotic cells (P < 0.05). To determine whether curcumin exerts these effects by altering the Notch signaling pathway, a phenomenon reported for other cancers, relative expression of Notch1 mRNA and protein were determined in curcumin-treated cells. Both mRNA and protein expression of Notch1 decreased with increasing curcumin dose (P < 0.05). Thus, curcumin appears to inhibit proliferation and induce apoptosis in hepatoma cells by altering the Notch signaling pathway.