Hemin inhibits cyclooxygenase-2 expression through nuclear factor-kappa B activation and ornithine decarboxylase expression in 12-O-tetradecanoylphorbol-13-acetate-treated mouse skin.
Inflammation induced by various stimuli has been found to be associated with increased risk for most types of human cancer. Inflammation facilitates the initiation of normal cells, as well as the growth of initiated cells and their progression to malignancy through production of proinflammatory cytokines and diverse reactive oxygen/nitrogen species. These also activate the signaling molecules that are involved in inflammation and carcinogenesis. Our previous studies have demonstrated that hemin inhibited 7,12-dimethylbenz[a]anthracene (DMBA)-induced bacterial mutagenesis and oxidative DNA damage, reduced the level of DNA-DMBA adduct and 12-O-tetradecanoylphorobl-13-acetate (TPA)-induced tumor formation in DMBA-initiated ICR mouse skin, and inhibited myeloperoxidase and ornithine decarboxylase (ODC) activity and H(2)O(2) formation in TPA-treated mouse skin. In the present study, to further elucidate the molecular mechanisms underlying the chemopreventive activity of hemin, its effect on the expression of ODC and cyclooxygenase (COX)-2, and the activation of nuclear factor-kappa B (NF-kappaB) and mitogen-activated protein kinases (MAPKs) regulating these proteins were explored in mouse skin with TPA-induced inflammation. Topically applied hemin inhibited ear edema and epidermal thickness in mice treated with TPA. Pretreatment with hemin reduced the expression of ODC and COX-2, and also reduced NF-kappaB activation in TPA-stimulated mouse skin. In addition, hemin suppressed the TPA-induced activation of extracellular signal-regulated protein kinase (ERK) and p38 MAPK in a dose-dependent manner. Taken together, hemin inhibited TPA-induced COX-2 expression by altering NF-kappaB signaling pathway via ERK and p38 MAPK, as well as TPA-induced ODC expression in mouse skin. Thereby, hemin may be an attractive candidate for a chemopreventive agent.
Department of Oral Biology, Yonsei University College of Dentistry, 134 Shinchon-Dong, Seodaemoon-Ku, Seoul, Republic of Korea.
Jae Hee
JH
Park
Chang Ki
CK
Lee
Young Sun
YS
Hwang
Kwang-Kyun
KK
Park
Won-Yoon
WY
Chung
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology; D003872:Dermatitis / Q000378:metabolism*; D004789:Enzyme Activation; D005260:Female; D006427:Hemin / Q000494:pharmacology*; D007249:Inflammation / Q000139:chemically induced; D051379:Mice; D008813:Mice, Inbred ICR; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000096:biosynthesis*; D009955:Ornithine Decarboxylase / Q000378:metabolism*; D012867:Skin / Q000187:drug effects; D013755:Tetradecanoylphorbol Acetate
D000893:Anti-Inflammatory Agents; D052246:Cyclooxygenase 2 Inhibitors; D016328:NF-kappa B; D006427:Hemin; D051546:Cyclooxygenase 2; D020928:Mitogen-Activated Protein Kinases; D009955:Ornithine Decarboxylase; D013755:Tetradecanoylphorbol Acetate