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The interaction with Sp1 and reduction in the activity of histone deacetylase 1 are critical for the constitutive gene expression of IL‐1α in human melanoma cells
Author(s) -
Enya Kazuaki,
Hayashi Hidetoshi,
Takii Takemasa,
Ohoka Nobumichi,
Kanata Shinya,
Okamoto Takashi,
Onozaki Kikuo
Publication year - 2008
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1189/jlb.0106008
Subject(s) - trichostatin a , biology , microbiology and biotechnology , chromatin immunoprecipitation , transactivation , histone deacetylase , histone deacetylase inhibitor , histone deacetylase 2 , gene knockdown , hdac11 , transcription (linguistics) , regulation of gene expression , gene expression , promoter , gene , histone , genetics , linguistics , philosophy
A375‐6 human melanoma cells are sensitive to the antiproliferative effect of IL‐1. After a long period of culturing, we have obtained cells resistant to IL‐1. The resistant clone A375‐R8 constitutively produced IL‐1α. In this study, we identified a sequence, CGCC, located at −48 to −45 upstream of the transcription start site, to be essential for the constitutive IL‐1α gene activation. Specificity protein 1 (Sp1) and Sp3 bound to the nucleotide containing the sequence. Although the binding level to the nucleotide and expression level of Sp1 and Sp3 are comparable in A375‐R8 and A375‐6 cells, transactivation activity of Sp1 is higher in A375‐R8 cells as compared with A375‐6 cells. Sp3 could not transactivate the IL‐1α promoter. These results suggest that Sp1 but not Sp3 is important for IL‐1α gene activation. Trichostatin A (TSA), an inhibitor of histone deacetylase (HDAC), greatly augmented the IL‐1α promoter activity in A375‐6 cells to the level comparable with that in A375‐R8 cells. TSA also induced IL‐1α mRNA expression in A375‐6 cells. Sp1 and Sp3 bound to HDAC1 in A375‐R8 and A375‐6 cells. The chromatin immunoprecipitation assay revealed the binding of Sp1 and HDAC1 to the promoter region of the IL‐1α gene. The activities of HDAC bound to Sp1 and Sp3, and that of HDAC1 was lower in A375‐R8 cells as compared with A375‐6 cells. These results indicate that the reduction in the activity and interaction of HDAC1 with Sp1 are critical for the constitutive IL‐1α gene expression.