Background: Large epidemiological studies have shown that diets high in fruits reduce the risk of esophageal squamous cell carcinoma (ESCC).
Objective: The current study investigated the effects of black raspberries (BRBs) on gene expression during the development of preneoplastic esophagi in rats.
Methods: Using a post-initiation protocol, F344 rats were injected with N-nitrosomethylbenzylamine (NMBA) and then fed either a control diet or 5% BRBs. At weeks 9, 15, and 35, we euthanized subgroups of the rats and collected preneoplastic esophagi to isolate RNA samples for DNA microarray.
Results: Along the development of NMBA-induced preneoplastic esophagi, NMBA injections led to differential expression of 1181 genes comparing to control rats, and dietary BRBs modulated 428 genes in esophagi from NMBA-treated rats. There are 137 common genes between 1181 and 428 gene sets, and BRBs significantly reversed the expression of 133 genes. These genes are associated with multiple gene oncology functions. BRBs induced an 8.8-fold gene enrichment on the pathway of inflammatory response and regulated 10 genes involved in this pathway. Among them, BRBs significantly reversed the expression of pro-inflammatory cytokines, such as CCL2, S100A8, and IL19.
Conclusions: BRBs exhibit strong anti-inflammatory effects against NMBA-induced rat esophageal tumorigenesis.
Keywords: Black raspberries; DNA microarray; NMBA; inflammatory response; rat preneoplastic esophagi.