Abstract: OBJECTIVE: To study the synergistic effects of tumor suppression by low-concentration vincristine plus curcumin on HepG2 cell line and possible mechanisms. METHODS：Experiments included control(only medium)，curcumin only(20 μmol/L)，vincristine only(0.5，1，2 and 4 μg/ml) and curcumin(20 μmol/L) plus vincristine(1 μg/ml). We used cell counting to assess cell growth inhibition，colony formation assay to measure long-term effect of each treatment，DAPI staining to observe cell death type，mitochondrial membrane potential test to evaluate damage on mitochondria，flow cytometry(FCM) to analyse DNA contents and cell cycle distribution，RT-PCR to find responsible genes alterations. RESULTS：Compared with control and individual treatment，after 24 h，curcumin plus vincristine treatment could significantly suppress HepG2 cell growth in cell counting assay (P<0.05)，which was confirmed by colony formation assay. DAPI staining indicated increased apoptosis under combined treatment (P<0.01). Mitochondrial membrane potential was reduced which might explain the increased apoptosis. FCM showed apparent cell arrest in G2/M phase (P<0.05). RT-PCR detected the decrease in expressions of LRP and MDR1 as well as the increase in P21 expression (P<0.05). CONCLUSION：Curcumin plus low concentration vincristine could induce growth inhibition of HepG2，providing a new option for chemotherapy.

Key words: curcumin, vincristine, apoptosis, mitochondrial membrane potential, LRP, MDR1, P21