Plasminogen activator inhibitor-type 1 in Lewis lung carcinoma.
Plasminogen activator inhibitor-type 1 (PAI-1) was identified in extracts of Lewis lung carcinoma, and its immunohistochemical localization was studied together with that of urokinase-type (u-PA) and tissue-type (t-PA) plasminogen activators. All primary tumors (n = 11) contained heterogeneously distributed immunoreactivity against each of the three components. Most often, areas that contained u-PA immunoreactivity also contained PAI-1 immunoreactivity. However, several areas showed a strong u-PA immunoreactivity, but no or low PAI-1 immunoreactivity. The latter staining pattern was only found in peripheral areas, and usually in areas with histological signs of tissue destruction. Lung metastases always contained u-PA immunoreactivity, while PAI-1 immunoreactivity was found in most, but not all, metastases. t-PA immunoreactivity was found in a few scattered tumor cells, in primary carcinomas as well as metastases. Controls that included absorption with highly purified antigen preparations and immunoblotting, indicated that all the immunoreactivity represented genuine PAI-1, u-PA and t-PA, respectively. The results are consistent with an assumption that the plasminogen activation system, and particularly u-PA and PAI-1, plays a role in regulation of breakdown of extracellular matrix proteins during invasive growth in this carcinoma.
Kristensen
P
P
Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.
Pyke
C
C
Lund
L R
LR
Andreasen
P A
PA
Danø
K
K
D000818:Animals; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000032:analysis* / Q000473:pathology / Q000556:secondary; D051379:Mice; D008810:Mice, Inbred C57BL; D009368:Neoplasm Transplantation; D015849:Plasminogen Inactivators / Q000032:analysis*; D010959:Tissue Plasminogen Activator / Q000032:analysis; D014568:Urokinase-Type Plasminogen Activator / Q000032:analysis
D015849:Plasminogen Inactivators; D010959:Tissue Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator