6-Shogaol, an active constituent of ginger, inhibits breast cancer cell invasion by reducing matrix metalloproteinase-9 expression via blockade of nuclear factor-κB activation

BACKGROUND AND PURPOSE

Shogaols are reported to possess anti-inflammatory and anticancer activities. However, the antimetastatic potential of shogaols remains unexplored. This study was performed to assess the effects of shogaols against breast cancer cell invasion and to investigate the underlying mechanisms.

EXPERIMENTAL APPROACH

The anti-invasive effect of a series of shogaols was initially evaluated on MDA-MB-231 breast cancer cells using the matrigel invasion assay. The suppressive effects of 6-shogaol on phorbol 12-myristate 13-acetate (PMA)-induced matrix metalloproteinase-9 (MMP-9) gelatinolytic activity and nuclear factor-κB (NF-κB) activation were further determined.

KEY RESULTS

Shogaols (6-, 8- and 10-shogaol) inhibited PMA-stimulated MDA-MB-231 cell invasion with an accompanying decrease in MMP-9 secretion. 6-Shogaol was identified to display the greatest anti-invasive effect in association with a dose-dependent reduction in MMP-9 gene activation, protein expression and secretion. The NF-κB transcriptional activity was decreased by 6-shogaol; an effect mediated by inhibition of IκB phosphorylation and degradation that subsequently led to suppression of NF-κB p65 phosphorylation and nuclear translocation. In addition, 6-shogaol was found to inhibit JNK activation with no resulting reduction in activator protein-1 transcriptional activity. By using specific inhibitors, it was demonstrated that ERK and NF-κB signalling, but not JNK and p38 signalling, were involved in PMA-stimulated MMP-9 activation.

CONCLUSIONS AND IMPLICATIONS

6-Shogaol is a potent inhibitor of MDA-MB-231 cell invasion, and the molecular mechanism involves at least in part the down-regulation of MMP-9 transcription by targeting the NF-κB activation cascade. This class of naturally occurring small molecules thus have potential for clinical use as antimetastatic treatments.

(N1E,N2E)-N1,N2-Bis(4-hexyloxy-3-methoxybenzylidene)ethane-1,2-diamine

The title compound, C₃₀H₄₄N₂O₄, was obtained from the dimerization of 4-hexyl­oxyvanillin with ethyl­enediamine in 95% methanol solution. It adopts a trans configuration with respect to the C=N bond and possesses a crystallographically imposed centre of symmetry.

Cyclooxygenase-2 enhances alpha2beta1 integrin expression and cell migration via EP1 dependent signaling pathway in human chondrosarcoma cells

Background

Cyclooxygenase (COX)-2, the inducible isoform of prostaglandin (PG) synthase, has been implicated in tumor metastasis. Interaction of COX-2 with its specific EP receptors on the surface of cancer cells has been reported to induce cancer invasion. However, the effects of COX-2 on migration activity in human chondrosarcoma cells are mostly unknown. In this study, we examined whether COX-2 and EP interaction are involved in metastasis of human chondrosarcoma.

Results

We found that over-expression of COX-2 or exogenous PGE₂ increased the migration of human chondrosarcoma cells. We also found that human chondrosarcoma tissues and chondrosarcoma cell lines had significant expression of the COX-2 which was higher than that in normal cartilage. By using pharmacological inhibitors or activators or genetic inhibition by the EP receptors, we discovered that the EP1 receptor but not other PGE receptors is involved in PGE₂-mediated cell migration and α2β1 integrin expression. Furthermore, we found that human chondrosarcoma tissues expressed a higher level of EP1 receptor than normal cartilage. PGE₂-mediated migration and integrin up-regulation were attenuated by phospholipase C (PLC), protein kinase C (PKC) and c-Src inhibitor. Activation of the PLCβ, PKCα, c-Src and NF-κB signaling pathway after PGE₂ treatment was demonstrated, and PGE₂-induced expression of integrin and migration activity were inhibited by the specific inhibitor, siRNA and mutants of PLC, PKC, c-Src and NF-κB cascades.

Conclusions

Our results indicated that PGE₂ enhances the migration of chondrosarcoma cells by increasing α2β1 integrin expression through the EP1/PLC/PKCα/c-Src/NF-κB signal transduction pathway.

4-Hexyloxy-3-methoxybenzaldehyde

The title compound, C₁₄H₂₀O₃, is a synthetic analogue with a long aliphatic side chain of the important food additive and flavoring agent, vanillin. There are two independent mol­ecules in the asymmetric unit, each having an essentially planar conformation (r.m.s. deviations of 0.023 and 0.051Å for all non–H atoms of the two mol­ecules in the asymmetric unit).