Study on the Function of NAG-1 in Hepatocellular and Gastric Carcinoma Cells

BACKGROUND: Nonsteroidal anti-inflammatory drug activated gene (NAG-1) has proapoptotic activities in the colon and also in gastric cancer cells that lack any endogenous COX-2 expression. Recent studies have suggested that the proa- poptotic activity of NAG-1 is cell type specific. I investigated the cell proliferation, invasiveness and apoptosis in Hep3B cells and SNU719 cells by determining the different expression levels of NAG-1. In addition, I examined the gene profile in the Hep3B cells that have a stable expression of NAG-1. METHODS: SNU719 cells and several clones of Hep3B cells with a stable expression of NAG-1 were used. I reduced the expression level of NAG-1 via the RNAi method. An Agilent Human 22k microarray was used for studying the gene profile in Hep3B cells that had a stable expression of NAG-1. RESULTS: The expression level of NAG-1 did not influence apoptosis, cell proliferation and invasiveness in Hep3B cells. There was no correlation between the reduction of the endogenous NAG-1 expression and cell proliferation, including invasiveness, in the SNU719 cells. However, a knocked-down NAG-1 expression protected against apoptosis in the SNU719 cells. The microarray analysis results showed that 0.25% (58/22,575) of the genes were induced or repressed more than three fold in the Hep3B cells that had a stable expression of NAG-1. CONCLUSIONS: Proapoptotic activity of NAG-1 is found in gastric cancer cells, but not in hepatocellular cancer cells.

Molecular Targets of Dietary Polyphenols with Anti-inflammatory Properties

There is persuasive epidemiological and experimental evidence that dietary polyphenols have anti-inflammatory activity. Aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) have long been used to combat inflammation. Recently, cyclooxygenase (COX) inhibitors have been developed and recommended for treatment of rheumatoid arthritis (RA) and osteoarthritis (OA). However, two COX inhibitors have been withdrawn from the market due to unexpected side effects. Because conventional therapeutic and surgical approaches have not been able to fully control the incidence and outcome of many inflammatory diseases, there is an urgent need to find safer compounds and to develop mechanism-based approaches for the management of these diseases. Polyphenols are found in many dietary plant products, including fruits, vegetables, beverages, herbs, and spices. Several of these compounds have been found to inhibit the inflammation process as well as tumorigenesis in experimental animals; they can also exhibit potent biological properties. In addition, epidemiological studies have indicated that populations who consume foods rich in specific polyphenols have lower incidences of inflammatory disease. This paper provides an overview of the research approaches that can be used to unravel the biology and health effects of polyphenols. Polyphenols have diverse biological effects, however, this review will focus on some of the pivotal molecular targets that directly affect the inflammation process.