Adenovirus E1A represses protease gene expression and inhibits metastasis of human tumor cells.
Stable transfection of human tumor cell lines with the adenovirus-5 E1A gene repressed the expression of the secreted proteases, type IV collagenase, interstitial collagenase and urokinase. In addition, E1A blocked the 12-O-tetradecanoyl phorbol acetate (TPA) induction of interstitial collagenase transcription in HT1080 fibrosarcoma cells. Plasmids bearing the interstitial collagenase or type IV collagenase 5' flanking regions linked to a chloramphenicol acetyl transferase coding sequence were constructed and analysed for expression by transient cotransfections into HT1080 cells. Cotransfection with a plasmid bearing a functional E1A gene repressed transcription of the type IV collagenase promoter and blocked the TPA induction of the interstitial collagenase promoter. Furthermore, E1A repressed transcription from a TK promoter driven by AP-1 complex binding sites (TRE), suggesting that E1A interferes with the AP-1 trans-activation pathway. This effect was not, however, due to the repression of c-jun gene transcription by E1A. In fact, the expression of E1A rendered the c-jun gene hypersensitive to TPA induction. Concomitant with reduction in expression levels of secreted proteases, stable E1A transfectants showed reduced metastatic activity in vivo and reduced ability to traverse a reconstituted basement membrane in vitro. Monospecific anti-type IV collagenase antibodies inhibited invasive activity of parental tumor cell lines in the in vitro assay, suggesting a possible causal relationship between the repression of secreted proteases and loss of metastatic properties of the transformants.
Frisch
S M
SM
Division of Dermatology, Washington University School of Medicine, St. Louis, Missouri 63110.
Reich
R
R
Collier
I E
IE
Genrich
L T
LT
Martin
G
G
Goldberg
G I
GI
D017456:Adenovirus Early Proteins; D001483:Base Sequence; D002471:Cell Transformation, Neoplastic; D015500:Chloramphenicol O-Acetyltransferase / Q000032:analysis / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D015870:Gene Expression; D006801:Humans; D008666:Metalloendopeptidases / Q000235:genetics; D003012:Microbial Collagenase / Q000235:genetics; D008969:Molecular Sequence Data; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D009856:Oncogene Proteins, Viral / Q000502:physiology*; D010447:Peptide Hydrolases / Q000235:genetics* / Q000502:physiology; D016755:Proto-Oncogene Proteins c-jun; D011519:Proto-Oncogenes; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014157:Transcription Factors / Q000235:genetics; D014158:Transcription, Genetic; D014162:Transfection
D017456:Adenovirus Early Proteins; D004268:DNA-Binding Proteins; D009856:Oncogene Proteins, Viral; D016755:Proto-Oncogene Proteins c-jun; D014157:Transcription Factors; D015500:Chloramphenicol O-Acetyltransferase; D010447:Peptide Hydrolases; D008666:Metalloendopeptidases; D003012:Microbial Collagenase; D013755:Tetradecanoylphorbol Acetate