title: NSAID activated gene (NAG-1), a modulator of tumorigenesis.
abstract: The NSAID activated gene (NAG-1), a member of the TGF-beta superfamily, is involved in tumor progression and development. The over-expression of NAG-1 in cancer cells results in growth arrest and increase in apoptosis, suggesting that NAG-1 has anti-tumorigenic activity. This conclusion is further supported by results of experiments with transgenic mice that ubiquitously express human NAG-1. These transgenic mice are resistant to the development of intestinal tumors following treatment with azoxymethane or by introduction of a mutant APC gene. In contrast, other data suggest a pro-tumorigenic role for NAG-1, for example, high expression of NAG-1 is frequently observed in tumors. NAG-1 may be like other members of the TGF-beta superfamily, acting as a tumor suppressor in the early stages, but acting pro-tumorigenic at the later stages of tumor progression. The expression of NAG-1 can be increased by treatment with drugs and chemicals documented to prevent tumor formation and development. Most notable is the increase in NAG-1 expression by the inhibitors of cyclooxygenases that prevent human colorectal cancer development. The regulation of NAG-1 is complex, but these agents act through either p53 or EGR-1 related pathways. In addition, an increase in NAG-1 is observed in inhibition of the AKT/GSK-3beta pathway, suggesting NAG-1 alters cell survival. Thus, NAG-1 expression is regulated by tumor suppressor pathways and appears to modulate tumor progression.
authors.affiliation: National Institute of Environmental Health Sciences, National Institute of Health, Research Triangle Park, NC 27709, USA. eling@niehs.nih.gov
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Eling
authors.forename: Seung Joon
authors.initials: SJ
authors.lastname: Baek
authors.forename: Minsub
authors.initials: M
authors.lastname: Shim
authors.forename: Chang Ho
authors.initials: CH
authors.lastname: Lee
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D015197:Carcinogenicity Tests; D002471:Cell Transformation, Neoplastic / Q000378:metabolism*; D016207:Cytokines / Q000502:physiology*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D016147:Genes, Tumor Suppressor / Q000502:physiology*; D055436:Growth Differentiation Factor 15; D006801:Humans; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D011471:Prostatic Neoplasms / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000737:chemistry / Q000378:metabolism
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D016207:Cytokines; C526140:GDF15 protein, human; C526141:Gdf15 protein, mouse; D055436:Growth Differentiation Factor 15; D016212:Transforming Growth Factor beta