Raf/ERK/Nrf2 signaling pathway and MMP-7 expression involvement in the trigonelline-mediated
inhibition of hepatocarcinoma cell migration
Sammanfattning
Background: Trigonelline occurs in many dietary food plants and has been found to have anti-
carcinogenic
activity. Trigonelline is also found in coffee which is one of the most widely consumed beverages.
Many
epidemiological studies have reported that coffee consumption has an inverse relationship with the
risk of
cirrhosis or hepatocellular carcinoma. It would be interesting to investigate whether trigonelline is an
ideal
chemoprevent agent to prevent cancer progression.
Methods: The protein expression was performed by western blotting. The trigonelline content in snow
pea
(Pisum sativum) was analyzed by high-performance liquid chromatography (HPLC). The migratory
activity
of human hepatocarcinoma cells (Hep3B) was assessed by using a wound migration assay. The
percentage
of each phase in the cell cycle was analyzed on a FACScan flow cytometer. Gene expression was
detected by
real-time reverse transcriptase-polymerase chain reaction techniques. Native gel analysis was
performed to
analyze the activity of superoxide dismutase (SOD), catalase and glutathione peroxidase.
Results: According to the data of HPLC analysis, P. sativum, which is a popular vegetable, has
relatively high
content of trigonelline. Our findings suggest that trigonelline is an efficient compound for inhibiting
Hep3B
cell migration. Trigonelline inhibited the migration of hepatoma cells at concentrations of 75100
mMwithout
affecting proliferation. Raf/ERK/Nrf2 protein levels and further downstream antioxidative enzymes
activity,
such as SOD, catalase, and glutathione peroxidase, significantly decreased after treatment with 100
mM of
trigonelline for 24 h. The migration inhibition of trigonelline is also related to its ability to regulate the
matrix
metalloproteinases 7 (MMP-7) gene expression.
Conclusions: In this study, protein kinase Ca (PKCa) and Raf/ERK/Nrf2 signaling pathway and MMP-7
gene expression were involved in the trigonelline-mediated migration inhibition of Hep3B cells. We
also
demonstrated that trigonelline inhibits Hep3B cell migration through downregulation of nuclear factor
E2-
related factor 2dependent antioxidant enzymes activity. This study analyzed the trigonelline content
in a
popular vegetable, snow pea, as a representative proof to prove that trigonelline is often found in the
daily
intake of food. Our finding suggested that trigonelline should be a useful chemopreventive agent
derived from
the daily intake of food to prevent cancer progression.