UNIPROT:P00750 - FACTA Search

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Query: UNIPROT:P00750 (PLA)
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The effect of Demulen (ethinyl estradiol 0.05 mg and ethynodiol diacetate 1 mg) and exercise on the level of plasminogen activators was studied in 25 women (12 controls and 13 contraceptive users). Plasma plasminogen activator level was increased by the use of the oral contraceptive and further increased by exercise. Urine plasminogen activator level was unchanged by the use of Demulen but, in both groups of subjects, was decreased by exercise.
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PMID:Plasminogen activator levels in plasma and urine during exercise and oral contraceptive use. 70 3

We have studied the estradiol sensitivity of primary human breast carcinomas in organ culture in a prospective pilot series of 109 tumors. The effect on plasminogen activator (PA) production was used as the end-point of estrogen action. We found that: (i) All tumors secreted detectable levels of urokinase-type PA (uPA); the level of basal uPA production was markedly heterogeneous but showed a weak association with the level of estrogen receptor positivity (p = 0.049). (ii) Only 23.5% of the tumors secreted tissue-type PA (tPA) in addition to uPA; a higher proportion of these tumors had histological characteristics indicative of good prognosis (18% vs. 3% of tumors secreting only uPA). (iii) Estradiol modulated uPA production and this effect was receptor-mediated. (iv) Responsiveness to estradiol was limited to a subset (25 of 60 or 41.7%) of estrogen and progesterone-receptor-positive tumors. (v) Of 20 evaluable patients with lymph-node and receptor-positive breast cancer who received adjuvant anti-estrogen therapy, 11 were identified as estradiol-sensitive by the in vitro PA assay; of these, 10 had no evidence of disease after a median follow-up period of 3+ years. In contrast, of 9 patients with tumors identified as estradiol-insensitive, 4 developed metastases within 3+ years of follow-up. (vi) Consistent with the previously reported inhibitory effect of corticosteroids on uPA production in organ cultures of human tumors, the basal culture level of uPA produced by tumors from patients receiving corticosteroids at the time of surgery was significantly lower than the level of uPA in the remaining tumors (p = 0.029). Also, tumors from patients receiving thyroid hormone, known to stimulate uPA in vitro, showed a slight trend toward increased production of uPA. These results show that hormone effects on tumor PA production are qualitatively similar in organ culture and in the host. This and the emerging individual correlation between sensitivity to estradiol in vitro, as determined by PA, and the clinical effectiveness of anti-estrogen therapy, underscore the potential usefulness of the organ culture approach.
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PMID:Estradiol modulation of plasminogen activator production in organ cultures of human breast carcinomas: correlation with clinical outcome of anti-estrogen therapy. 190 Dec 98

ES-1 cells, which showed a higher sensitivity to the cytocidal action of estradiol were isolated from a human breast cancer MCF-7 cell line. Growth of ES-1 cells was inhibited by a dose of 17-beta estradiol that stimulated the growth of the parental MCF-7 cells. Proteins secreted from MCF-7 and ES-1 cells when cultured with 17-beta estradiol were compared by sodium dodecyl sulfate-containing polyacrylamide gel electrophoresis (SDS-PAGE). Addition of estradiol to culture medium enhanced secretion of a protein of molecular mass of 52 kDa in media for both MCF-7 and ES-1 cell lines, but the secretion of a second 67 kDa protein was enhanced about 10-fold only in ES-1 cells. The analysis by SDS-PAGE of culture medium immunoprecipitated with anti-tissue-type plasminogen activator (t-PA) antibody demonstrated that the band of 67 kDa protein specifically secreted from estradiol-treated ES-1 cells contained t-PA. Zymography assays, quantitative immunoreactive assays, and Northern analysis showed about 5-fold specific increase by estradiol of t-PA with molecular mass of 65-70 kDa in ES-1 but not in its parental MCF-7 cells. Cellular level of the plasminogen activity was also specifically enhanced in ES-1 cells by estradiol, but only a slightly in MCF-7 cells. By contrast, another urokinase-type PA (u-PA) with molecular weight of 55 kDa showed very low level activity in both MCF-7 and ES-1 cell lines in the presence of estradiol. Formation of t-PA mRNA was specifically enhanced in ES-1 cells when ES-1 cells were treated for more than 12 h with 10(-8) M 17-beta estradiol. Estradiol did not elongate the lifetime of t-PA mRNA in ES-1 cells. A unique phenotype of ES-1 cells in response to estradiol is discussed in relation to activating expression of the t-PA gene.
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PMID:Enhanced production of tissue-type plasminogen activator by estradiol in a novel type variant of human breast cancer MCF-7 cell line. 211 58

1. Regulatory mechanism of cell growth of endometriosis in comparison with endometrium. Estradiol alone has no growth-promoting effect on both endometriotic and endometrial cells. Epidermal growth factor (EGF) stimulates cell growth of both cell types. Endometrial cells but not endometriotic cells produce and release EGF into culture media so that stimulatory effect of exogenous addition of EGF is blunted in endometrial cells. Estradiol exerts its mitogenic action by enhancing the mitogenic effect of EGF in endometrium. By contrast, the effect of estradiol is minimal in endometriotic cells, showing less dependency on estradiol for their proliferation. Progesterone inhibits cell growth of the both cell types in the same manner. 2. A biological role of EGF in endometriosis. Endometriotic cells possess EGF receptors. The affinity of the receptor is the same as that of endometrial cells. However, the number of receptor per cell is about half of that for endometrium. Estradiol increases the number of EGF receptors in endometrial cells which may explain the mitogenic effect of estradiol in the face of EGF. However, stimulatory effect of estradiol for EGF receptors is less pronounced in endometriotic cells. Mitogenic action of EGF is suggested to be mediated by phosphorylation of tyrosine residues of 170 kd protein in the tissues. EGF increases the production of tissue plasminogen activator (t-PA) and activates the aromatase activity of the both cell types. However, the stimulatory action of EGF on progestin receptor is observed only in endometrial cells. 3. Biochemical characterization of endometriotic cells in comparison with endometrial cells. Endometriotic tissues accumulate less amount of glycogen and XIII factor of blood coagulation as compared to endometrial tissues. The ability of endometriotic cells to release prostaglandin is also weaker, suggesting suppressed differentiated function of endometriotic cell. Endometriotic cells produce the same amount of CA125 as endometrial cells. Danazol and EGF inhibit the release of CA125 into culture media when standardized per cell. Therefore, normalization of CA125 levels during the treatment dose not always mean the reduction of the lesions but reflect the suppressed function of the endometriotic tissues. 4. Altered microenvironment of endometriotic tissues. An analysis of peritoneal fluid. The amount of peritoneal fluid (PF) with endometriosis increased throughout the menstrual cycle. A number of macrophage is reported to increase in PF with endometriosis.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Fundamental and clinical studies on biochemical properties of endometriosis in comparison with endometrium]. 250 2

As stated earlier, the mammalian ovary maintains the continuous development of follicles, but only a few are selected to ovulate and form corpora lutea. These processes are regulated primarily by the gonadotropins and involve specific, sequential changes in the function of theca cells and granulosa cells. Data from recent studies (summarized in Figure 3) show that specific genes are turned on or off at different stages of follicular growth in response to estradiol and different amounts of gonadotropins and cAMP. For example, mRNA for RII51 in granulosa cells and theca cells increases in association with small increased in cAMP but is markedly reduced by the LH surge and high cAMP. The content of mRNA for other kinase subunits, RI and C alpha, show little or no change during similar hormonal changes. In theca cells, mRNA for 17 alpha-hydroxylase increased and decreased in a manner similar to that for RII51. In contrast, levels of mRNA for P450scc increased only gradually in follicles but were markedly increased by the LH surge and high concentrations of cAMP and then appeared to be constitutively expressed in rat corpora lutea in a cAMP-independent manner. PGS and t-PA appear to follow yet another pattern: rapid induction by the LH surge followed by a rapid decline in association with ovulation. One major task for reproductive endocrinologists and molecular biologists now is to determine how low and high concentrations of cAMP act to turn on and turn off the expression of these specific genes at specific times during follicular maturation. A working model of the molecular events occurring in theca and granulosa cells of PO follicles is shown in Figure 4. LH acts on theca cells via cAMP ro regulate both P450scc and P450(17) alpha mRNA levels, leading to increased biosynthesis of androstenedione. The mechanisms by which cAMP acts in theca cells remain to be determined but appear to involve an increase in the content of RII51, P450scc, and P450(17) alpha. In granulosa cells, androstenedione is converted to estradiol by the aromatase P450 enzyme system. Estradiol, in turn, binds to estradiol receptors present in these cells and may thereby regulate gene expression. However, despite the presence of estradiol and estradiol receptors, little or no effect of estradiol is observed unless FSH acts via the FSH receptor to increase intracellular concentrations of cAMP. In a manner not yet understood, cAMP appears to enhance the actions of estradiol.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Molecular aspects of hormone action in ovarian follicular development, ovulation, and luteinization. 328

We have adapted an Ortho ICP-22 flow cytometer (Ortho Instruments, Westwood MA) for the simultaneous measurement of three independent fluorochromes and cell volume. This has been accomplished by the addition of a third photomultiplier tube and the development of a new electronic cell volume (ECV) flow cell. Cells are first analyzed as they pass through the 100 U ECV aperture and are then excited approximately 15 musec later by the 365 nm mercury are beam reflected by a 400 nm dicroic mirror. Independent blue, green and red signals can be associated by a delay circuit to the ECV signal from the same cell. We have developed this system as an aid in the analysis of tumor cell and macrophage heterogeneity and differentiation. The choice of stain combinations to be used is extremely flexible and permits the analysis of a wide range of enzyme activities in conjunction with DNA/RNA and phagocytic probes. Data presented indicates the value of this approach in identifying the presence of plasminogen activator-like activity in both tumor and inflammatory cells within a malignant effusion as well as the quantitative expression of a number of markers of macrophage differentiation. Although the described techniques have been developed on a mercury arc instrument, they can be used equally well with cell sorters.
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PMID:Simultaneous three color and electronic cell volume analysis with a single UV excitation source. 618 88

MCF-7 human breast cancer cells secrete two immunologic types of plasminogen activator, one related to urokinase, the other unrelated. We have now examined whether estrogen stimulation of secreted plasminogen activator activity reflects an increase in one or both types. Examined semiquantitatively by sodium dodecyl sulfate-polyacrylamide gel electrophoretic zymography, the conditioned media of control cells were seen to contain a major activator band (Mr approximately 54,000) immunologically related to urokinase and a barely discernible doublet (Mr approximately 64,000 and Mr approximately 68,000). Addition of estradiol or, at much higher concentrations, testosterone led to marked enhancement of doublet activity, while the 54-kDa band was invariant. The 64-68-kDa doublet was immunoreactive with antiserum directed against Bowes melanoma tissue plasminogen activator but not with antiurokinase antibodies. Enhancement of doublet activity was correlated with hormone-induced increases in total secreted plasminogen activator activity. Neither progesterone nor dexamethasone increased total activity or the 64-68-kDa zones of lysis. Estradiol and testosterone alterations were blocked by appropriate concentrations of an estrogen antagonist (LY156758), actinomycin D, or cycloheximide. Regulation of MCF-7 cell-secreted tissue plasminogen activators thus appears to be mediated by an estrogen receptor process and to require sustained RNA and protein synthesis.
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PMID:Estradiol preferentially enhances extracellular tissue plasminogen activators of MCF-7 breast cancer cells. 654 3

The influence of ethinylestradiol (EE2) and d-norgestrel (d-Ng) was studied in a melanoma cell line producing a tissue-type plasminogen activator (t-PA) very similar to or identical with the t-PA isolated in extracts from human uterus. The cell cultures were exposed to the two contraceptive steroids by addition of EE2 or d-Ng dissolved in a week alcoholic solution to the culture media, in which the released t-PA was assayed by an immunoradiometric method. A strongly stimulating effect of ethanol (0.76% w/v) on the t-PA production was demonstrated. Whereas, EE2 in the concentration of 1.7 X 10(-7)M and d-Ng in the concentration of 8.6 X 10(-7)M both caused a significantly reduced secretion of t-PA, and this effect was independent of whether the cell cultures were grown to confluency in the presence of the two synthetic steroids or not. It was concluded, that the two contraceptive steroids had an inhibitory effect on the production of t-PA in melanoma cell culture.
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PMID:Ethinylestradiol and d-norgestrel regulation of plasminogen activator in a human melanoma cell line. 654 56

The effect of the antiestrogens tamoxifen and nafoxidine on the growth of the human breast cancer cell line MCF-7 is modified by both serum and insulin. Tamoxifen inhibition of the growth of MCF-7 cells in culture is reduced as the concentration of serum in the medium is increased from 0.1% to 5 to 10%. Estradiol does not stimulate cell growth over the same range of serum levels. Insulin changes the sensitivity of MCF-7 cells to both estrogen and antiestrogens. Cells growing in media containing insulin are less sensitive to inhibition by either tamoxifen or nafoxidine than are cells growing in its absence. In addition, higher concentrations of estradiol are required to stimulate the production of plasminogen activator when cells are grown in media containing insulin. This effect of insulin can be accounted for by the finding that insulin lowers the level of estrogen receptor in MCF-7 cells without altering the binding constant for the hormone. Cells grown with insulin have an average of 21,000 +/- 4,700 (S.D.) estrogen binding sites/cell compared to 62,000 +/- 9,700 sites/cell in cells grown in the absence of insulin. This difference in receptor level is sufficient to account for the difference in the concentration of estradiol needed for equivalent induction of plasminogen activator in cultures with or without insulin. These results indicate that the level of estrogen receptor in breast cancer cells can be changed and that the sensitivity of such cells, both to estrogen and to antiestrogens, is altered by changes in the level of estrogen receptor. They also have implications concerning the mechanism by which antiestrogens act to inhibit the growth of mammary tumor cells.
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PMID:Effects of serum and insulin on the sensitivity of the human breast cancer cell line MCF-7 to estrogen and antiestrogens. 700 31

The present studies examined the biochemical characteristics which were carried on from parent cells during fusion of human skin fibroblasts (HSF) with spleen cells of BALB/c mice preimmunized with hormone-responsive and nonresponsive human malignant melanoma cells (HMMC-ShA and HMMC-SR). The melanoma cells used as immunogens were either unmodified or preincubated with vibrio cholera neuraminidase (VCN), with estradiol (E), or with progesterone (P). Responsiveness was monitored by (3H) thymidine and (35S) methionine incorporation. Responsiveness to estradiol, concanavalin A (Con A) and to phytoheamagglutinin (PHA) were carried out, whereas malignancy was suppressed extensively in the cloned hybrids. On the immunizing tumor cells, VCN treatment enhanced (3H) thymidine but reduced (35S)-methionine incorporation and malignancy of the estradiol responsive melanoma cells (HMMC-ShA). VCN treatment enhanced (3H)-thymidine incorporation, but had no effect on (35S)-methionine incorporation and malignancy of the estradiol nonresponsive HMMC-SR cells. Estradiol treatment enhanced plasminogen activator (PA) activity and malignancy, whereas progesterone treatment reduced (inhibited) plasminogen activator activity and suppressed malignancy of the immunizing tumor cells. The PA from estradiol-responsive and from nonresponsive melanoma cells differed in their electrophoretic mobility on polyacrylamide gel electrophoresis.
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PMID:Correlation between plasminogen activator activity of immunizing tumor cells and complement-mediated cytotoxic antibodies secreted by cloned hybrid cells. 719 36

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