The 100% of NPC cell lines, 80% of primary NPC and 22.2% of CN tissues showed methylation in DLC-1 promoter, while DLC-1 expression was recovered in seven NPC cell lines after 5-aza-dC treatment.
DLC-1 expression was restored in the 5-8F NPC cell line, which lacks DLC-1 expression, and the biological characteristics of 5-8F-DLC‑1 cells were analyzed by MTT assay, colony formation assay, flow cytometry (FCM), tumorigenesis analysis in nude mice, as well as invasion and migration assay.
Taken together, our results suggest that DLC-1 might be an NPC-related tumor suppressor gene affected by aberrant promoter methylation and gene deletion.