[Effect of hepatocyte growth factor on invasion of ovarian cancer cell line SKOV3 and its signal transduction pathway]

Abstract

Background & objective: Hepatocyte growth factor (HGF) specifically binds to its receptor c-met, activates a complex set of intracellular pathways, and plays important roles in regulating tumor invasion, metastasis, and angiogenesis. HGF and c-met are overexpressed in ovarian cancer. This study was designed to investigate the role of HGF in ovarian cancer invasion and its signal transduction pathway.

Methods: HGF-induced invasion of ovarian cancer cell line SKOV3 was analyzed with Boyden chamber invasion assay. The expression changes of c-met and matrix metalloproteinase-9 (MMP-9) in SKOV3 cells before and after treatment with HGF and nuclear factor kappaB (NF-kappaB) inhibitor pyrrolidine dithiocarbamate (PDTC) were measured by real-time reverse transcription-polymerase chain reaction (RT-PCR), Western blot, and flow cytometry. The expression of NF-kappaB in SKOV3 cells was evaluated by immunocytochemistry and Western blot.

Results: The invasive cells were significantly more in HGF group than in control group and PDTC plus HGF group (343+/-13 vs. 167+/-11 and 241+/-10, P<0.01). HGF promoted the expression of MMP-9 mRNA by 5.66+/-0.10 folds, but had no effect on c-met mRNA expression; PDTC suppressed the HGF-driven expression of MMP-9 mRNA by 2.75+/-0.80 folds. The positive rates of c-met and MMP-9 were significantly higher in HGF-treated cells than in control cells [(96.6+/-2.0)% vs. (73.3+/-2.4)%, P<0.01; (74.6+/-4.4)% vs. (16.0+/-2.9)%, P<0.01]. The protein levels of c-met and MMP-9 were significantly higher in HGF-treated cells than in control cells (2.84+/-0.18 vs. 1.65+/-0.19, P<0.01; 2.94+/-0.13 vs. 0.54+/-0.18, P<0.01). PDTC significantly suppressed the HGF-driven expression of MMP-9 protein: the positive rate and protein level of MMP-9 were (25.8+/-3.7)% and 0.87+/-0.14 (P<0.05). HGF promoted the expression of NF-kappaB protein in a time-dependent manner. The expression peak appeared 1 h after treatment with HGF (from 0.42+/-0.11 to 1.16+/-0.21, P<0.01). PDTC significantly inhibited the HGF-driven expression of NF-kappaB protein (0.38+/-0.12, P<0.01).

Conclusion: HGF might stimulate the invasion of SKOV3 cells by up-regulating the expression of MMP-9 via NF-kappaB pathway.