A comparison of the effect of several factors on the plasminogen activator activity of cloned lines from an ethylnitrosourea-induced glioma and from normal tissue.
Cells from gliomas induced by N-ethyl-N-nitrosourea have a high basal level of plasminogen activator activity compared with cells from normal tissue. Plasminogen activator activity is known to be affected by many substances but whether inhibition or stimulation occurs depends on the cell and agent involved. It is not clear whether tumour and control cells from the same type of tissue respond similarly. A comparison has been made of the effect of several factors on both cell associated and secreted enzyme activity of cloned lines from a glioma and normal tissue. The effect of two cAMP elevating compounds was stimulatory while that of the steroid, dexamethasone, was generally inhibitory for both cells. However, the polypeptide hormone, epidermal growth factor, had a differential effect. It caused an increase in secreted enzyme activity in the tumour line but had no such effect on the control clone. The precise mechanism by which this occurs is unknown. Co-operative effects of the enzyme and growth hormone could result in more aggressive behaviour of the tumour cells.
Neame
S J
SJ
Department of Histopathology, UCM School of Medicine, London, UK.
Roscoe
J P
JP
D000818:Animals; D001932:Brain Neoplasms / Q000139:chemically induced / Q000378:metabolism*; D002460:Cell Line; D002772:Cholera Toxin / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005038:Ethylnitrosourea; D005910:Glioma / Q000139:chemically induced / Q000378:metabolism*; D010960:Plasminogen Activators / Q000378:metabolism*; D051381:Rats
D005576:Colforsin; D004815:Epidermal Growth Factor; D003907:Dexamethasone; D002772:Cholera Toxin; D010960:Plasminogen Activators; D005038:Ethylnitrosourea