Demonstration of a possible link between high grade malignancy in dimethylbenz[a]anthracene-induced rat mammary carcinoma and increased urokinase plasminogen activator content.
Recent reports have suggested that tissue-type plasminogen activator activity is regulated by estrogen in 7,12-dimethylbenz[a]anthracene-induced rat mammary carcinoma type I cells but is not necessarily regulated by estrogen in type II mammary carcinoma cells. We have compared the biological features of these two types of mammary carcinoma cells and have found that, although there is no difference in estrogen receptor content between these two cell types, the plasminogen activator activity markedly differs. Tissue-type plasminogen activator activity is significantly higher in type I carcinoma than in type II carcinoma, urokinase-type activity is significantly higher in type II carcinoma than in type I carcinoma. When these two types were compared in terms of rate of tumor growth, type II carcinomas clearly showed more rapid growth than type I carcinomas. Survival studies showed significantly shorter survival of type II tumor-bearing rats compared with type I tumor-bearing rats. Furthermore, type II carcinomas contained a greater proportion of aneuploid cells than type I carcinomas. These results suggest that type II carcinoma cells, in which estrogen is unable to regulate tissue-type plasminogen activator activity, are considered to be of a higher grade of malignancy than type I carcinoma cells.
Yamashita
J
J
Department of Surgery II, Kumamoto University Medical School, Japan.
Inada
K
K
Yamashita
S
S
Matsuo
S
S
Nakashima
Y
Y
Ogawa
M
M
D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D002455:Cell Division / Q000502:physiology; D004247:DNA / Q000032:analysis / Q000235:genetics; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000201:enzymology* / Q000378:metabolism / Q000401:mortality; D011003:Ploidies; D051381:Rats; D011919:Rats, Inbred Strains; D011960:Receptors, Estrogen / Q000378:metabolism*; D015996:Survival Rate; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism*
D011960:Receptors, Estrogen; D015127:9,10-Dimethyl-1,2-benzanthracene; D004247:DNA; D014568:Urokinase-Type Plasminogen Activator