Olive oil polyphenols suppress the TGF‑α‑induced migration of hepatocellular carcinoma cells

Abstract

Oleuropein and 3-hydroxytyrosol (3-HT) are natural polyphenols present in olive oil that are known to exhibit potent anti-oxidant activities and exert protective effects against a number of human diseases. In the liver, olive oil polyphenols have been demonstrated to prevent hepatocellular carcinoma (HCC) cell growth. However, little is known about their effects against HCC cell migration. Therefore, the present study investigated whether or not oleuropein and 3-HT were involved in the suppression of transforming growth factor-α (TGF-α)-induced migration of human HCC cells using human HCC-derived HuH7 cells. The TGF-α-induced migration of HuH7 cells was significantly and dose-dependently suppressed by oleuropein and 3-HT. This study group demonstrated previously that the TGF-α-induced activation of AKT and stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) were involved in HuH7 cell migration. In addition to these protein kinases, the present study examined the involvement of TGF-α-induced activation of extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (MAPK) and Rho kinase in HuH7 cell migration. TGF-α-induced HuH7 cell migration was decreased by SB203580, a p38 MAPK inhibitor, and Y27632, a Rho kinase inhibitor. However, PD98059, an inhibitor of the upstream kinase activating ERK, did not suppress the TGF-α-induced migration of HuH7 cells. Although AKT, SAPK/JNK, p38 MAPK and Rho kinase pathways were suggested to be involved in the TGF-α-induced migration of HuH7 cells, 10-30 µM 3-HT did not exhibit any suppressive effect on the TGF-α-stimulated activities of these kinases. The results of the present study suggest that olive oil polyphenols suppressed the TGF-α-induced migration of HCC cells.

Heat shock protein 70 positively regulates transforming growth factor-α-induced hepatocellular carcinoma cell migration via the AKT signaling pathway

“…TGF-α has been reported to induce the migration of human HCC-derived HuH7 cells in a transwell cell migration assay [ 17 , 18 , 19 , 21 ]. In contrast, the knockdown of HSP70 suppresses migration and invasion of the HCC cells, SMMC7721 and Hep3B [ 8 ].…”

“…P38 MAPK, JNK and Rho-kinase signaling pathways function as positive regulators in TGF-α induced HuH7 cell migration [ 17 , 19 ]. However, the activation of p44/p42 MAPK is closely associated with HCC development and HuH7 cell proliferation [ 24 , 25 ] but is not involved in the TGF-α-induced migration of HuH7 cells [ 19 ]. Therefore, the effects of VER155008 on TGF-α-stimulated phosphorylation of p38 MAPK, JNK, Rho-kinase substrate MYPT-1 and p44/p42 MAPK in HuH7 cells were measured.…”

“…A transwell cell migration assay using a Boyden chamber (polycarbonate membrane with 8-μm pores, Transwell; Corning Costar Co., Cambridge, MA) was performed as described previously [ 17 , 18 , 19 , 20 , 21 ]. The cells (1 × 10⁵ cells/well) were seeded onto the upper chamber in serum-free RPMI-1640 medium.…”

“…The cells were then lysed and sonicated in 800 μl lysis buffer (62.5 mM Tris-HCl [pH 6.8], 2% sodium dodecyl sulfate [SDS], 50 mM dithiothreitol and 10% glycerol). SDS-polyacrylamide gel electrophoresis (PAGE) was performed with the cell lysate as described previously [ 17 , 18 , 19 , 20 , 21 ]. Western blot analyses were performed using phospho-specific AKT (T308; 1:200000), phospho-specific p38 MAPK (1:20000), phospho-specific JNK (1:1000), phospho-specific MYPT-1 (1:1000), phospho-specific p44/p42 MAPK (1:50000) and GAPDH (1:1000) as primary antibodies.…”

“…Activation of the EGFR signaling pathway is known to promote the presence of HCC tumor cells in circulation and HCC cell metastasis [ 16 ]. In addition, TGF-α has been reported to the induce activation of the AKT, p38 mitogen activated protein kinase (MAPK), c- jun N-terminal kinase (JNK) and Rho-kinase signaling pathways as well as the subsequent migration of human HCC-derived HuH7 cells [ 17 , 18 , 19 ].…”