Differential modulation of AMPK signaling pathways by low or high levels of exogenous reactive oxygen species in colon cancer cells.
This study was undertaken to examine the effect of low and high concentrations of H2O2 on cancer cell proliferation and apoptosis, and AMPK signaling pathways in HT-29 human colon cancer cells. Nontoxic doses of H2O2 (10 microM) induced cancer cell proliferation, whereas the toxic level of 1,000 microM H2O2 induced apoptosis. The stimulation of cell proliferation was accompanied with an increase in cyclooxygenase-2 (COX-2), and apoptosis induced by high-dose H2O2 was correlated with the activation of AMPK and negatively correlated with COX-2 expression. These results suggest that ROS at nontoxic levels can stimulate cancer cell growth by regulating AMP-activated protein kinase (AMPK) and/or COX-2, and the abundant exogenous ROS linked to the growth inhibition through modulating AMPK signaling pathways.
Park
In-Ja
IJ
Department of Food and Nutrition, Hannam University, 133 Ojeong-dong Daedeok-gu, Daejeon 306-791, Korea.
Hwang
Jin-Taek
JT
Kim
Young Min
YM
Ha
Joohun
J
Park
Ock Jin
OJ
D055372:AMP-Activated Protein Kinases; D049109:Cell Proliferation / Q000187:drug effects; D003110:Colonic Neoplasms / Q000201:enzymology* / Q000473:pathology*; D019073:HT29 Cells; D006801:Humans; D009097:Multienzyme Complexes / Q000378:metabolism / Q000502:physiology*; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism* / Q000494:pharmacology; D015398:Signal Transduction / Q000502:physiology*
D009097:Multienzyme Complexes; D017382:Reactive Oxygen Species; D017346:Protein Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases