Mechanisms associated with mitochondrial-generated reactive oxygen species in cancer

• Published in: Canadian journal of physiology and pharmacology Vol. 88; no. 3; pp. 204 - 219
• Main Authors: VERSCHOOR, Meghan L, WILSON, Leigh A, SINGH, Gurmit
• Format: Conference Proceeding Journal Article
• Language: English
• Published: Plattsburgh, NY National Research Council of Canada 01.03.2010; NRC Research Press; Canadian Science Publishing NRC Research Press
• Subjects: Amino acids; Animals; Biological and medical sciences; Cancer; Colorectal cancer; DNA binding proteins; Fundamental and applied biological sciences. Psychology; Gene expression; Genetic aspects; Humans; Medical treatment; Mitochondria; Mitochondria - genetics; Mitochondria - metabolism; Mutation - genetics; Neoplasms - genetics; Neoplasms - metabolism; Reactive Oxygen Species - metabolism; Signal Transduction - physiology; Studies; Transcription Factors - genetics; Transcription Factors - metabolism; Tumor proteins; Vertebrates: anatomy and physiology, studies on body, several organs or systems; United States; Oxygen; Vertebrata; Reactive oxygen species; Mitochondria; Mammalia; Hypoxia; Malignant tumor; Transcription factor; Cancer
• ISSN: 0008-4212; 1205-7541
• DOI: 10.1139/Y09-135

The mitochondria are unique cellular organelles that contain their own genome and, in conjunction with the nucleus, are able to transcribe and translate genes encoding components of the electron transport chain (ETC). To do so, the mitochondria must communicate with the nucleus via the production of reactive oxygen species (ROS) such as hydrogen peroxide (H2O2), which are produced as a byproduct of aerobic respiration within the mitochondria. Mitochondrial signaling is proposed to be altered in cancer cells, where the mitochondria are frequently found to harbor mutations within their genome and display altered functional characteristics leading to increased glycolysis. As signaling molecules, ROS oxidize and inhibit MAPK phosphatases resulting in enhanced proliferation and survival, an effect particularly advantageous to cancer cells. In terms of transcriptional regulation, ROS affect the phosphorylation, activation, oxidation, and DNA binding of transcription factors such as AP-1, NF-kappaB, p53, and HIF-1alpha, leading to changes in target gene expression. Increased ROS production by defective cancer cell mitochondria also results in the upregulation of the transcription factor Ets-1, a factor that has been increasingly associated with aggressive cancers.