Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Culture fluids of avian sarcoma virus (ASV)-transformed but not normal chicken embryo cells frequently elicited a mitogenic response in normal avian and murine lymphocytes. We examined the possibility that plasminogen activator (PA) might be responsible for the observed mitogenic effect. PA activity, present in culture medium, was correlated positively with lymphocyte mitogenic capacity. Treatment of cells with phorbol myristate acetate, which elevates PA levels, increased mitogenesis. Similar treatment with dexamethasone, which inhibits PA biosynthesis and/or secretion, reduced lymphocyte mitogenic activity. Addition to culture fluids of either benzamidine or diisopropylfluorophosphate, both specific PA inhibitors, blocked lymphocyte proliferative responsiveness to culture fluids. In contrast, neither epsilon-amino-caproic acid nor trasylol, which inhibits plasmin esterase activity but not PA, abrogated lymphocyte responsiveness. Furthermore, purified urokinase, an enzyme of similar substrate specificity to PA, had lymphocyte stimulatory activity. These results strongly suggest that PA can function as a lymphocyte mitogen.
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PMID:Plasminogen activator is an apparent lymphocyte mitogen. 625 59

The effects of 12-O-tetradecanoylphorbol-13-acetate (TPA) on the sarc protein kinase of normal chick embryo fibroblasts (CEF) and of the src kinase of cells transformed by a temperature-sensitive mutant of avian sarcoma virus (CEF-tsASV) were studied and compared with the known effects of TPA on cell morphology and plasminogen activator (PA) activity. One hr after the addition of TPA to normal CEF, there was a 3- to 8-fold stimulation of kinase activity when compared to control cultures; during the subsequent 24 hr, TPA produced less than a 2-fold stimulation. Although TPA induced levels of PA in CEF which were equivalent to those produced by cEF-tsASV grown at 36 degrees, the latter cells contained much higher levels of kinase activity than those of CEF plus TPA. In addition, TPA failed to enhance the kinase activity of CEF-tsASV at either 36 degrees or 40 degrees, even though at both temperatures TPA induced morphological changes and markedly enhanced PA activity. These results suggest that the effects of TPA on morphology and PA are not due to an effect on these protein kinases.
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PMID:Effect of tumor promoters on sarc gene expression in normal and transformed chick embryo fibroblasts. 626 Mar 44

Under conditions employed in our laboratory, tumors which are induced by avian sarcoma virus (ASV) usually grow progressively for several weeks and then regress. In order to further understand the basis for tumor regression in this model, we compared avian sarcoma cells which were cultured from tumors at different stages of development in terms of various phenotypic properties. The results indicate that tumor cells which are derived from progressively-growing sarcomas are rapidly growing, produce large quantities of the enzyme plasminogen activator, and have much in common generally with chicken embryo fibroblast (CEF) cells that have been transformed by ASV. In contrast, tumor cells that are obtained from regressors have elevated levels of hexose transport, grow very slowly, are greatly enlarged and display properties that are characteristic of senescent cells in culture.
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PMID:Phenotypic differences between tumor cells derived from different stages of neoplastic growth. 628 92