cAMP attenuates interleukin-1-stimulated macrophage colony-stimulating factor (M-CSF) expression.
Macrophage colony-stimulating factor (M-CSF) is a multifunctional cytokine attributed with key biological functions beyond the first discovered role in promoting proliferation of myeloid cell lineage. The human pancreatic cancer cell line MIA PaCa-2, from which the M-CSF gene was originally cloned, was used to study regulation of M-CSF expression. Expression of M-CSF was inducible by interleukin-1alpha (IL-1alpha), lipopolysaccharide (LPS) and PMA as demonstrated by a biological activity assay, Northern-blot analysis and reverse transcriptase (RT) PCR. Treatment of the cells with forskolin or dibutyryl-cAMP attenuated the expression of M-CSF induced by IL-1alpha or LPS, but not by PMA. Electromobility shift assays showed that IL-1alpha predominantly activated nuclear factor kappaB (NF-kappaB), while PMA preferentially activated activator protein-1 (AP-1). The activation of NF-kappaB, but not AP-1, could be attenuated by cAMP elevation. Relative RT-PCR demonstrated that the expression of a 1.6-kb M-CSF mRNA transcript was more effectively induced by IL-1alpha than a 4.0-kb transcript. By and large the induced expression of both mRNA transcripts could be attenuated by cAMP. M-CSF promoter-driven luciferase reporter-gene assays revealed that cAMP elevation attenuated the IL-1-induced transcription activation of the M-CSF promoter, but it had no effect on PMA-induced transcription. Our findings suggest that cAMP regulates M-CSF gene expression at the transcriptional level and that its inhibitory effect involves NF-kappaB signalling pathway.
Kamthong
P J
PJ
Department of Molecular Biology and Immunology, University of North Texas Health Science Center at Fort Worth, 3500 Camp Bowie Blvd, Fort Worth, TX 76107, USA.
Wu
F M
FM
Wu
M C
MC
D001483:Base Sequence; D000242:Cyclic AMP / Q000502:physiology*; D017931:DNA Primers; D005786:Gene Expression Regulation / Q000187:drug effects*; D017930:Genes, Reporter; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D016173:Macrophage Colony-Stimulating Factor / Q000096:biosynthesis / Q000235:genetics*; D016328:NF-kappa B / Q000378:metabolism; D011401:Promoter Regions, Genetic; D015398:Signal Transduction; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014407:Tumor Cells, Cultured
D017931:DNA Primers; D007375:Interleukin-1; D016328:NF-kappa B; D018808:Transcription Factor AP-1; D016173:Macrophage Colony-Stimulating Factor; D000242:Cyclic AMP