Epigenetic Upregulation of Metallothionein 2A by Diallyl Trisulfide Enhances Chemosensitivity of Human Gastric Cancer Cells to Docetaxel through Attenuating NF-κB Activation.
Antioxid Redox Signal. 2016 Jan 22. Epub 2016 Jan 22. PMID: 26801633
AIMS: Metallothionein 2A (MT2A) and NF-κB are both involved in carcinogenesis and cancer chemosensitivity. We previously showed decreased expression of MT2A and IκB-α in human gastric cancer (GC) associated with poor prognosis of GC patients. The present study investigated the effect of diallyl trisulfide (DATS), a garlic-derived compound, and docetaxel, on regulation of MT2A in relation to NF-κB in GC cells.
RESULTS: DATS attenuated NF-κB signaling in GC cells, resulting in G2/M cell cycle arrest and apoptosis, culminating in the inhibition of cell proliferation and tumorigenesis in nude mice. The anti-GC effect of DATS was attributable to its capacity to epigenetically upregulate MT2A, which in turn, enhanced transcription of IκB-α to suppress NF-κB activation in GC cells. Combination of DATS with docetaxel exhibited a synergistic anti-GC activity accompanied by MT2A upregulation and NF-κB inactivation. Histopathologic analysis of GC specimens from patients showed a significant increase in MT2A expression following docetaxel treatment. GC patients with high MT2A expression in tumor specimens showed significantly improved response to chemotherapy and prolonged survival compared with those with low MT2A expression in tumors. Innovation and Conclusion: We conclude that DATS exerts its anti-GC activity and enhances chemosensitivity of GC to docetaxel by epigenetic upregulation of MT2A to attenuate NF-κB signaling. Our findings delineate a mechanistic basis of MT2A/NF-κB signaling for DATS- and docetaxel-mediated anti-GC effect, suggesting that MT2A may be a chemosensitivity indicator in GC patients receiving docetaxel-based treatment and a promising target for more effective treatment of GC by combination of DATS and docetaxel.