Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0376358 (prostate cancer)
 59,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We developed an assay to measure at acid pH the phosphotyrosine phosphatase activity in sera from patients with prostatic cancer. The method used quantifies the inorganic phosphate liberated from phosphotyrosine after incubation with serum, followed by the deproteinization of the reaction mixture. A high acid phosphatase (EC 3.1.3.2) activity towards phosphotyrosine was observed in all sera from patients with increased activity of prostatic acid phosphatase. This activity represented 96% of prostatic acid phosphatase and 77% of total acid phosphatase activities. Moreover, it was correlated (r = 0.91) with the amount of serum prostatic acid phosphatase determined by radioimmunoassay. When serum acid phosphatase activity was measured on several phosphorylated substrates, preferential hydrolysis was demonstrated for those in which the phosphate group was esterified on an aromatic ring rather than those presenting an aliphatic chain. Among phosphoamino acids, only phosphotyrosine was a good substrate, with little or no activity observed with phosphoserine and phosphothreonine. Human seminal plasma and partially purified prostatic acid phosphatase, tested for their activity on some of these substrates, gave similar results. On the other hand, sera from patients with above-normal alkaline phosphatase activity and no prostatic disease showed little or no activity on phosphotyrosine at both acid and alkaline pH values. Evidence is presented that the prostatic acid phosphatase in serum is a specific phosphotyrosine acid phosphatase.
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PMID:Prostatic acid phosphatase in serum of patients with prostatic cancer is a specific phosphotyrosine acid phosphatase. 169 55

To examine the possibility that differences in protein tyrosine phosphorylation contributed to differences in fibroblast growth factor (FGF) responsiveness of clonally derived C3 (modestly responsive) and T5 (highly responsive) rat prostate cancer cells, we evaluated the ability of orthovanadate to affect prostate cancer cell thymidine incorporation. These analyses showed that C3 cell FGF insensitivity was not attributable to enhanced protein phosphotyrosine phosphatase activity. Analyses of acidic FGF (aFGF)-mediated protein phosphorylation showed mitogen-caused, time-dependent tyrosine phosphorylation of C3 and T5 cell FGF receptors (FGFRs) and other proteins having a mass of 190, 150, 120, 100, 90, 80, 74, 60/62, 50, 42, or 28 kilodaltons. Although marked differences characterized aFGF mediated intensity of tyrosine phosphorylation, the notable commonality of tyrosine phosphorylation and the mass of the phosphorylated proteins suggested that C3 and T5 cells may use the ras and/or protein kinase C (PKC) pathways for FGF-mediated signal transduction. The PKC agonist 12-O-tetradecanoyl-phorbol-13-acetate (TPA) caused concentration-dependent increases in T5 cell thymidine incorporation. In contrast, TPA did not enhance thymidine incorporation of C3 cells or mitogen-sensitive NRK cells included as a nonneoplastic control. TPA also significantly enhanced T5 cell proliferation, whereas identical treatment did not affect proliferation of either C3 or NRK cells. Either 12 or 24 h treatment with 200 or 2000 ng/ml TPA caused complete PKC alpha and partial PKC delta down-regulation in C3, T5, and NRK cells. Consequently, the failure of TPA to affect C3 or NRK cell thymidine incorporation or proliferation was not attributable to potential TPA ineffectiveness in these cells. Survey immunological analyses showed that all three cell lines lacked PKC beta, PKC eta, and PKC theta. In contrast, T5 cells contained abundant amounts of PKC epsilon, whereas the PKC epsilon content of C3 and NRK cells was near the limit of detection. TPA treatment of T5 cells evoked only partial PKC epsilon down-regulation. Both aFGF and basic FGF (bFGF) promoted concentration-dependent enhancement of TPA-pretreated T5 cell thymidine incorporation, and the effects of combined TPA and either aFGF or bFGF treatment were additive. Neither aFGF nor bFGF was able to enhance thymidine incorporation of TPA-pretreated C3 cells beyond the modest effects elicited by FGF treatment of C3 controls.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Protein kinase C-dependent and -independent pathways of signal transduction in prostate cancer cells: fibroblast growth factor utilization of a protein kinase C-independent pathway. 851 90

We review the mechanisms involved in prostatic growth based on androgens and product of neuroendocrine secretion, with special reference to the role of somatostatin (SS) in the inhibition of neoplastic growth. Our contributions in the field confirm the antiproliferative effect of SS on the prostate is mediated by phosphotyrosine phosphatase SHP-1, that is present in human prostate. This enzyme plays a role in the control of prostatic cell proliferation and in the progression of prostate cancer. Besides, we consider its presence may determine the therapeutic potential of SS in the control of prostate cancer.
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PMID:[Phosphotyrosine phosphatase SHP-1, somatostatin and prostate cancer]. 1524 98

Tensins are large intracellular proteins believed to link the extracellular matrix to the cytoskeleton via integrins. Tensins are multidomain proteins consisting of homologous C1, PTPase, C2, SH2 and PTB domains. Full-length Tensin proteins can undergo cleavage inside cells, thus yielding domains in isolation that may have discrete subcellular localisations and downstream effects. We expressed different isoforms of Tensin2 and their individual domains as recombinant green fluorescent protein (GFP)-fusion constructs in DU145 human prostate cancer cells. Under fluorescence confocal microscopy, the isolated domains of Tensin2 all displayed discrete distributions throughout the cytoplasm and the nucleus. In particular, partial constructs containing the C1 domain localised preferentially to the nucleus, including the isolated C1 domain and the PTPase domain. In contrast, all three full-length isoforms of Tensin2 were present exclusively in discrete punctate bodies throughout the cytoplasm. This punctate staining showed colocalisation with the tumour suppressor protein DLC-1 as well as with actin (phalloidin). Furthermore, DU145 cells transiently expressing partial Tensin2 constructs containing the PTB domain showed an increased haptotactic migration. In addition, stimulation of renal carcinoma cells stably expressing Tensin2 by the survival factor Gas6 caused phosphorylation of its receptor Axl, but no effect on Tensin2, which was already maximally phosphorylated at time 0. In conclusion, our results indicate that differential proteolytic cleavage of Tensin2 can liberate domains with discrete localisations and functions, which has implications for the role of Tensins in cancer cell survival and motility.
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PMID:Individual domains of Tensin2 exhibit distinct subcellular localisations and migratory effects. 1974 64