Abstract
Differential display PCR analysis (DD-PCR) was used to identify novel genes that respond to IGF-I treatment in human MCF-7 breast cancer cells. Fifty-three cDNAs showed alterations in their mRNA levels in IGF-I treated cells. One of these genes showed a significant increase in the mRNA level in IGF-I treated cells in comparison to non-treated cells. We named this gene HIRF1 (human IGF-I regulated factor 1). Nucleotide blast analysis revealed that this gene has a 100% sequence identity with the sequence for BTG1 (B-cell translocation gene) binding factor 1 (human CCR4-associated factor 1 gene, hCAF1). By alignment of cloned HIRF1 cDNA and genomic DNA 8p21.3-p22 sequence, we were able to determine the exon-intron structure of the cloned HIRF1 gene on chromosome 8. Northern blot and real-time PCR analysis showed that BTG1 and c-fos reached their maximal expression fairly early within 10 min to 1 h, and decreased to basal levels after 3 h of IGF-I treatment. HIRF1/hCAF1 expression reached maximal stimulation after 3 h of IGF-I treatment and then gradually decreased to basal level. HIRF1 and BTG1 mRNA was inhibited by inhibitors of the cell signaling pathways, PI3/Akt kinase and MAPK kinases (ERK1/2 and p38). In summary, cloned HIRF1/hCAF1 is coregulated with BTG1 in response to IGF-I. The regulation of these genes as early response genes may have an important role in differentiation, growth and proliferation of breast cancer cells.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Amino Acid Sequence
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Base Sequence
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Blotting, Northern
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Breast Neoplasms / genetics
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Breast Neoplasms / pathology
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Cell Line, Tumor
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Chromones / pharmacology
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Enzyme Inhibitors / pharmacology
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Flavonoids / pharmacology
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Gene Expression Regulation, Neoplastic / drug effects*
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Humans
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Imidazoles / pharmacology
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Insulin-Like Growth Factor Binding Proteins / genetics
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Insulin-Like Growth Factor Binding Proteins / metabolism
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Insulin-Like Growth Factor I / pharmacology*
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Mitogen-Activated Protein Kinases / antagonists & inhibitors
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Molecular Sequence Data
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Morpholines / pharmacology
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Neoplasm Proteins / genetics*
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Phosphoinositide-3 Kinase Inhibitors
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Pyridines / pharmacology
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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Receptor, IGF Type 1 / genetics
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Sequence Homology, Amino Acid
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Transcription Factors / genetics*
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Transcription, Genetic / drug effects
Substances
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CNOT8 protein, human
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Chromones
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Enzyme Inhibitors
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Flavonoids
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Imidazoles
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Insulin-Like Growth Factor Binding Proteins
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Morpholines
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Neoplasm Proteins
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Phosphoinositide-3 Kinase Inhibitors
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Pyridines
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RNA, Messenger
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Transcription Factors
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BTG1 protein, human
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2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
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Insulin-Like Growth Factor I
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Receptor, IGF Type 1
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Mitogen-Activated Protein Kinases
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4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)imidazole
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2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one