BACKGROUND: We investigated whether the plant-derived agent triptolide (TPL) could effectively inhibit the growth and invasion of human hepatocellular carcinoma (HCC) cells.

MATERIAL AND METHODS: MHCC-97H cells were treated with various concentration of TPL for various times. To detect the effect of NF-κB on TPL-induced signal pathways, MHCC-97H cells were transfected with p65 siRNA or p65 cDNA, then treated with TPL. We detected cell survival and apoptosis by MTT, soft-agar colony formation assay, flow cytometry, and TUNEL assay. Cell migration and invasion was determined by Matrigel invasion and a wound-healing assay. NF-κB activity was detected by electrophoretic mobility shift assay (EMSA); MMP-9 activity was detected by ELISA. Western blot and real-time PCR (RT-PCR) assays were used to detect p65 and MMP-9 protein and mRNA expression. A subcutaneously implanted tumor model of MHCC-97H cells in nude mice was used to assess the effects of TPL on tumorigenesis in vivo.

RESULTS: We showed that TPL treatment significantly suppressed growth and induced apoptosis of MHCC-97H cells in a dose- and time-dependent manner in vitro. Furthermore, TPL treatment inhibited invasion in vitro and inhibited the growth and lung metastasis of MHCC-97H cells in vivo. NF-κB and MMP-9 were inactivated with TPL treatment. Overexpression of p65 restored MMP-9 activity and inhibited the TPL anti-tumor effect on MHCC-97H cells. Knockdown of p65 blocked MMP-9 activation and enhanced TPL-induced cell apoptosis and survival inhibition, and TPL inhibition of migration and invasion in vitro.

CONCLUSIONS: TPL treatment inhibited MHCC-97H cell growth, invasion, and metastasis in vitro and vivo, suggesting that TPL could be developed as a potential therapeutic agent for the treatment of HCC.

Keywords: Antineoplastic Agents, Alkylating - pharmacology, Carcinogenesis - drug effects, Carcinoma, Hepatocellular - metabolism, Cell Movement - drug effects, Cell Proliferation - drug effects, Diterpenes - pharmacology, Epoxy Compounds - pharmacology, Liver Neoplasms - metabolism, Matrix Metalloproteinase 9 - metabolism, Phenanthrenes - pharmacology, Random Allocation, Signal Transduction - drug effects