TY - JOUR
T1 - n-Butyrate reduces the expression of β-galactoside α2,6-sialyltransferase in Hep G2 cells
AU - Shah, S.
AU - Lance, P.
AU - Smith, T. J.
AU - Berenson, C. S.
AU - Cohen, S. A.
AU - Horvath, P. J.
AU - Lau, J. T.Y.
AU - Baumann, H.
PY - 1992/5/25
Y1 - 1992/5/25
N2 - n-Butyrate, a short chain fatty acid that is produced by colonic bacterial fermentation, is detectable in portal blood and induces differentiation in various human neoplastic cell lines. Earlier reports indicated ∼20-fold induction in vitro by n-butyrate of the sialyltransferase that catalyzes terminal glycosylation of GMS ganglioside in HeLa and colon cancer cells. We previously isolated a 1.3-kilobase cDNA for a human β-galactoside α2,6-sialyltransferase, for which N-linked glycoproteins are the acceptors. We report here that treatment of Hep G2 cells with 5 mM n-butyrate for 24 h reduced β-galactoside α2,6-sialyltransferase mRNA levels by ∼90%. Reductions in mRNA level were followed by ∼75 and ∼90% reductions, respectively, in specific β-galactoside α2,6-sialyltransferase enzyme activity after treatment for 24 and 36 h with 5 mM n-butyrate. However, in contrast with earlier reports of enhanced ganglioside synthesis in response to n-butyrate treatment, incubation of Hep G2 cells with n-butyrate did not alter the ganglioside pattern as assessed by thin layer chromatography of lipids extracted from treated cells. Nuclear run-on reactions indicated that the rate of transcription of β-galactoside, α2,6-sialyltransferase was not altered by treatment with 5 mM n-butyrate for 24 h, but the effects of this treatment on cytoplasmic levels of β-galactoside α2,6-sialyltransferase mRNA were largely negated by co-treatment with actinomycin D or cycloheximide. Therefore, our results show that n-butyrate reduces expression of mature β-galactoside α2,6-sialyltransferase mRNA by post-transcriptional mechanisms.
AB - n-Butyrate, a short chain fatty acid that is produced by colonic bacterial fermentation, is detectable in portal blood and induces differentiation in various human neoplastic cell lines. Earlier reports indicated ∼20-fold induction in vitro by n-butyrate of the sialyltransferase that catalyzes terminal glycosylation of GMS ganglioside in HeLa and colon cancer cells. We previously isolated a 1.3-kilobase cDNA for a human β-galactoside α2,6-sialyltransferase, for which N-linked glycoproteins are the acceptors. We report here that treatment of Hep G2 cells with 5 mM n-butyrate for 24 h reduced β-galactoside α2,6-sialyltransferase mRNA levels by ∼90%. Reductions in mRNA level were followed by ∼75 and ∼90% reductions, respectively, in specific β-galactoside α2,6-sialyltransferase enzyme activity after treatment for 24 and 36 h with 5 mM n-butyrate. However, in contrast with earlier reports of enhanced ganglioside synthesis in response to n-butyrate treatment, incubation of Hep G2 cells with n-butyrate did not alter the ganglioside pattern as assessed by thin layer chromatography of lipids extracted from treated cells. Nuclear run-on reactions indicated that the rate of transcription of β-galactoside, α2,6-sialyltransferase was not altered by treatment with 5 mM n-butyrate for 24 h, but the effects of this treatment on cytoplasmic levels of β-galactoside α2,6-sialyltransferase mRNA were largely negated by co-treatment with actinomycin D or cycloheximide. Therefore, our results show that n-butyrate reduces expression of mature β-galactoside α2,6-sialyltransferase mRNA by post-transcriptional mechanisms.
UR - http://www.scopus.com/inward/record.url?scp=0026707317&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0026707317&partnerID=8YFLogxK
M3 - Article
C2 - 1316908
AN - SCOPUS:0026707317
SN - 0021-9258
VL - 267
SP - 10652
EP - 10658
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 15
ER -