Regulation of 12-lipoxygenase in rat intestinal epithelial cells during differentiation and apoptosis induced by sodium butyrate.
We evaluated the expression and activity of rat 12-lipoxygenase (LO) in rat intestinal epithelial (RIE) cells during apoptosis and cell differentiation. Sodium butyrate (NaBT) treatment induced wild-type RIE (W-RIE) cells to undergo differentiation and apoptosis. Alkaline phosphatase (ALP) activity, a marker of cell differentiation, and DNA fragmentation, an index of apoptosis, were increased by NaBT treatment. Arachidonic acid was metabolized primarily to 12-hydroxyeicosatetraenoic acid (HETE) suggesting induction of 12-LO activity. In contrast, sense-RIE (S-RIE) cells engineered to overexpress COX-2 were resistant to apoptosis by treatment with 5 mM NaBT and NaBT did not induce 12-LO activity. The upregulation of 12-LO expression by NaBT in W-RIE cells was confirmed at both the transcriptional and translational level but 12-LO was undetectable in S-RIE cells following NaBT treatment. The expression of 12-LO mRNA in W-RIE cells occurs as early as 6 h after treatment and reaches maximum expression at 24 h following treatment. This inducible 12-LO was isolated by RT-PCR and identified as rat "leukocyte-type" 12-LO. The level of 12-LO expression in W-RIE cells was dependent on the concentration of NaBT and appears to reflect the extent of cell differentiation. NDGA, a lipoxygenase inhibitor, attenuated induction of ALP activity by NaBT treatment of W-RIE cells. These observations suggested that 12-LO is regulated by treatment with NaBT and is associated with cell differentiation in rat intestinal epithelial cells.
Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, 27709, USA.
H
H
Kamitani
H
H
Ikawa
L C
LC
Hsi
T
T
Watanabe
R N
RN
DuBois
T E
TE
Eling
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001092:Arachidonate 12-Lipoxygenase / Q000235:genetics / Q000378:metabolism*; D016718:Arachidonic Acid / Q000378:metabolism; D001483:Base Sequence; D020148:Butyric Acid / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000166:cytology / Q000187:drug effects*; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology; D009637:Masoprocol / Q000494:pharmacology; D051381:Rats
D017931:DNA Primers; D018076:DNA, Complementary; D016859:Lipoxygenase Inhibitors; D020148:Butyric Acid; D016718:Arachidonic Acid; D009637:Masoprocol; D001092:Arachidonate 12-Lipoxygenase; D000469:Alkaline Phosphatase