Insulin-like growth factor I differentially regulates the expression of HIRF1/hCAF1 and BTG1 genes in human MCF-7 breast cancer cells.
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.
Vadgama
Jaydutt V
JV
Division of Cancer Research and Training, Department of Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, CA 90059, USA. javadgam@cdrewu.edu
Scuric
Zorica
Z
Chakrabarti
Rita
R
Marzo
Ehrnad
E
Shen
Dejun
D
Wu
Yanyuan
Y
D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D001943:Breast Neoplasms / Q000235:genetics / Q000473:pathology; D045744:Cell Line, Tumor; D002867:Chromones / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D018969:Insulin-Like Growth Factor Binding Proteins / Q000235:genetics / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D008969:Molecular Sequence Data; D009025:Morpholines / Q000494:pharmacology; D009363:Neoplasm Proteins / Q000235:genetics*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017526:Receptor, IGF Type 1 / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic / Q000187:drug effects
C489780:CNOT8 protein, human; D002867:Chromones; D004791:Enzyme Inhibitors; D005419:Flavonoids; D007093:Imidazoles; D018969:Insulin-Like Growth Factor Binding Proteins; D009025:Morpholines; D009363:Neoplasm Proteins; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011725:Pyridines; D012333:RNA, Messenger; D014157:Transcription Factors; C074086:BTG1 protein, human; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1; D020928:Mitogen-Activated Protein Kinases; C090942:4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)imidazole; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one