Interferon regulatory factor-1 gene abnormality and loss of growth inhibitory effect of interferon-alpha in human hepatoma cell lines.
The effect of IFN-alpha on the growth of 5 hepatoma cell lines and a normal liver-derived cell line were examined. IFN dose-dependently inhibited the growth of cell lines except for HLE and PLC/PRF/5 in which the inhibition only occurred at a high concentration over 10,000 IU/ml. IFN-alpha induced the G1 arrest of these cells according to upregulation of p21WAF-1 expression, which is induced in PLC/PRF/5 and HLE only at a high IFN concentration. The receptor for IFN-alpha was well expressed in all the cell lines. DNA rearrangement of IRF-1 was detected in HLE and PLC/PRF/5 by Southern blotting, while IRF-2 gene was preserved. IFN-induced gene expressions were compared between HCC-T, HCC-M and PLC/PRF/5. RT-PCR demonstrated that the full-length IRF-1 and -2 mRNA was transcribed in all cell lines, but the mRNA amount of former gene in PLC/PRF/5 was less than that in HCC-T and HCC-M, about 1/10 by competitive RT-PCR. The sequence analysis of IRF-1 cDNA was performed and the full-length mRNA transcription was reconfirmed in PLC/PRF/5, but no significant point mutation was detected. These results suggest that IFN-alpha inhibits hepatoma growth by increasing p21WAF-1 expression only when the IRF-1 gene is preserved normally.
Tada
S
S
Department of Internal Medicine, School of Medicine, Keio University, Tokyo 160, Japan.
Saito
H
H
Tsunematsu
S
S
Ebinuma
H
H
Wakabayashi
K
K
Masuda
T
T
Ishii
H
H
D001483:Base Sequence; D015139:Blotting, Southern; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000473:pathology; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D004273:DNA, Neoplasm / Q000032:analysis; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D050856:Interferon Regulatory Factor-1; D050836:Interferon Regulatory Factor-2; D016898:Interferon-alpha / Q000494:pharmacology*; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000235:genetics* / Q000378:metabolism; D017354:Point Mutation; D012333:RNA, Messenger / Q000378:metabolism; D017471:Receptors, Interferon / Q000378:metabolism; D012097:Repressor Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D014157:Transcription Factors; D014407:Tumor Cells, Cultured
D004273:DNA, Neoplasm; D004268:DNA-Binding Proteins; C494257:IRF1 protein, human; C494229:IRF2 protein, human; D050856:Interferon Regulatory Factor-1; D050836:Interferon Regulatory Factor-2; D016898:Interferon-alpha; D010750:Phosphoproteins; D012333:RNA, Messenger; D017471:Receptors, Interferon; D012097:Repressor Proteins; D014157:Transcription Factors