Identification of active substances from Streptomyces culture fluids using p53-independent expression of p21/WAF1/Cip1 gene and their mode of action.
An assay system was constructed to identify chemicals that have a potential to induce p21/WAF1 gene, a target of the tumor suppressor p53 critical for negative growth regulation. Screening of about 1300 culture fluids of Streptomyces resulted in identification of active substances which induced the p21 gene in a p53-independent manner; one was a mixture of four members of the actinomycin group, and the other was trichostatin A. Transcriptional regulatory regions of p21 gene for induction by actinomycin D and trichostatin A were determined by transient expression of luciferase constructs in cells which are p53-deficient (Saos-2) or express a mutated form of p53 (TMK-1). The essential transcriptional elements for the response to these drugs localize within 210 bp of the 5'-upstream region of human p21 gene, and Sp1 elements were determined to be critical for the induction. DNA-binding activity of Sp1 was not increased in cells treated with these drugs, but kinase inhibitors such as staurosporin and wortmannin inhibited the induction.
Department of Microbiology, Showa University School of Pharmaceutical Sciences, Tokyo, Japan.
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K
Egawa
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Nishigori
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Kunimoto
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T
Takeuchi
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Nose
D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000096:biosynthesis* / Q000235:genetics; D003609:Dactinomycin / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D005809:Genes, Regulator; D017930:Genes, Reporter; D016158:Genes, p53; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology*; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D012516:Osteosarcoma / Q000235:genetics / Q000378:metabolism; D010770:Phosphotransferases / Q000037:antagonists & inhibitors; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology*; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D016329:Sp1 Transcription Factor / Q000378:metabolism; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism; D013302:Streptomyces / Q000378:metabolism*; D014162:Transfection; D014170:Transformation, Genetic; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*
C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004791:Enzyme Inhibitors; D006877:Hydroxamic Acids; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D016329:Sp1 Transcription Factor; D016159:Tumor Suppressor Protein p53; D003609:Dactinomycin; C012589:trichostatin A; D008156:Luciferases; D010770:Phosphotransferases