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.
Kamitani
H
H
Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, 27709, USA.
Ikawa
H
H
Hsi
L C
LC
Watanabe
T
T
DuBois
R N
RN
Eling
T E
TE
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