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)

In an attempt to identify an indicator(s) specifically associated with prostatic cancer prostatic fluid was collected by rectal massage from patients with prostatic cancer, prostatitis, benign prostatic hyperplasia and from those without recognized prostatic lesions in order to measure various immunoproteins. The proteins examined were IgG, IgA, IgM, complements C3 and C4, and transferrin. Prostatic fluid samples were subjected first to immunoelectrophoresis. Distinct differences in C3, C4 and transferrin concentrations were noted between patients with prostatic cancer and other patients. These proteins were stained heavily in the electrophoresis gels of fluid from cancer patients but were either missing or lightly stained in all other groups. These qualitative determinations were replaced subsequently by a quantitative measurement using the radial immunodiffusion technique. Results of the latter study confirmed the aforementioned observations and indicated that the levels of C3, C4 and transferrin in the prostatic fluid of cancer patients were elevated significantly when compared to all other patient groups. These observations indicate that the measurement of complements C3 and C4, and transferrin in the prostatic fluid may assist in the identification of patients with a high risk of prostatic cancer.
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PMID:Analysis of specific proteins in prostatic fluid for detecting prostatic malignancy. 8 26

Transferrin receptors (TfR) were measured in benign and malignant prostatic cells by performing Scatchard analysis following the administration of 125I-transferrin. Established human prostate cancer cell lines (PC-3 and DU-145) as well as biologically aggressive variants (PC-3 ASC and PC-3 DES) were shown to possess significant levels of high affinity TfR when assessed in vitro. In contrast, TfR content was negligible in cultured stromal cell fractions derived from human benign prostatic hyperplasia (BPH) specimens. Scatchard analysis was also performed on in vivo derived prostatic tissues: tumors resulting from the subcutaneous xenografting of PC-3 ASC cells into athymic, nude mice and fresh BPH surgical specimens. These tissues were dissociated and their stromal and epithelial components separated. TfR were only detected in the epithelial component of both malignant and benign epithelial cells. PC-3 ASC tumor cells exhibited TfR levels comparable to their in vitro expression and these levels were 10-fold greater than in the BPH cells. These findings suggest that elevated TfRs may serve as another useful marker of the transformed phenotype within human prostate tumor systems.
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PMID:Elevated transferrin receptor content in human prostate cancer cell lines assessed in vitro and in vivo. 168 56

Monoclonal antibodies have been used to detect tumor cells in bone marrow of patients with neuroblastoma, breast cancer, small cell lung cancer, prostatic cancer and gastrointestinal carcinoma. By comparative analysis immunocytology proved to be more sensitive than conventional cytology and histology and had the additional advantage of specificity. A positive correlation exists between the presence of tumor cells in bone marrow and the extent of the primary tumor. The proliferative potential of the micrometastatic cells was assessed by characterization of EGF and transferrin receptors, tumorigenicity was shown by xenotransplantation experiments in nu/nu mice in a few instances. First follow-up studies indicate that the presence of disseminated tumor cells in bone marrow can be taken as predicting the subsequent development of overt metastasis.
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PMID:Detection, characterization and tumorigenicity of disseminated tumor cells in human bone marrow. 210 96

Traditional serum markers used in the diagnosis of prostate cancer lack sensitivity and specificity. Prostatic fluid is in direct contact with the prostate epithelium and, thus, has been investigated as a better source for potentially useful markers. Since prostatic fluid contents can enter the urine directly through the urethra, without prerequisite entry into blood, proteins present in significant quantities in prostatic fluid represent candidate markers for entry into the urine, particularly in diseases affecting the prostate epithelium, such as adenocarcinoma. High concentrations of transferrin in prostatic fluid led us to examine urine transferrin levels, using an immunoturbidimetric technique. Urine transferrin was significantly increased in 18 out of 22 patients with prostate cancer in comparison to age-matched controls. Since there was no evidence of increased transferrin excretion, we suggest that prostatic fluid is the source of transferrinuria.
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PMID:A preliminary study of urinary transferrin as a marker for prostatic cancer. 243 78

Urinary transferrin, serum prostatic acid phosphatase (PAP) and prostatic-specific antigen (PSA) concentrations were measured in patients with prostatic cancer, prostatitis, benign prostatic hypertrophy (BPH) and in a control group. In contrast to recently published data it is concluded that urinary transferrin is not suitable as a tumor marker for prostatic carcinoma. Receiver Operating Characteristic curves were constructed to compare the diagnostic value of the different tests at different cutoff values. Sensitivity and specificity of the urinary marker are extremely low compared to the serum markers PAP and especially PSA, making the former not suitable as an additional marker.
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PMID:The diagnostic value of urinary transferrin compared to serum prostatic specific antigen (PSA) and prostatic acid phosphatase (PAP) in patients with prostatic cancer. 246 Feb 72

Metastasis represents a hallmark of the tumor cell's escape from normal cellular behavior to acquired invasive and migratory style. Metastasis of prostate cancer (Pca) depends upon the interplay of a series of hematogenous and hematopoietic factors. We investigated the role of some of those factors implicated in the dissemination process in two separate sublines of adenocarcinoma of the prostate. Our data revealed that (1) the urokinase plasminogen activator activity was significantly higher in R3327-AT3, an aggressive metastatic tumor, as compared to R3327-G, a nonmetastatic tumor of the prostate, (2) the concentration of platelets decreased, and the platelet-aggregating activity increased significantly when the platelets were reacted with exogenous aggregating agents and tumor effusions to suggest that activation of the hemostatic system could protect tumor cells from immunosurveillance and facilitate the process of hematogenous dissemination, and (3) transferrin, which has been reported to have a growth-promoting effect on Pca, did not show any appreciable effect on tumor growth but did alter the level of in vitro adherence which possibly could lead to better attachment and increased invasive behavior of tumor cells.
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PMID:Metastatic behavior of prostatic tumor as influenced by the hematopoietic and hematogenous factors. 898 19

We have cloned the gene encoding the prostate-specific membrane (PSM) antigen, which is recognized by the 7E11C-5 antibody. The antigen is strongly expressed in prostate cancer, and the antibody has been approved for use as an imaging agent for detection of prostatic cancer metastasis. The gene was unique and encoded a type II membrane protein. The only clue to its potential function was found in the cDNA coding sequences from 1250 to 1700, which had a modest but significant homology with transferrin-receptor, demonstrating a 54% homology of nucleic acid sequence. In comparing the mRNA obtained from normal prostate with that obtained from cancerous or lymph node carcinoma of the prostate (LNCaP) cells, normal cells produced a shorter alternative spliced species that encoded a cytosolic form of the protein, and not a membrane protein. It appeared that, as the prostatic cells became cancerous, there was a nearly 100-fold difference in expression of the ratio of the messages encoding the 2 forms, with the cytosolic form (PSM') predominant in normal cells and the membrane form (PSM) predominant in cancer cells. The other tissue in which the membrane antigen form of PSM is highly expressed is the membrane brush border of the small intestine of the proximal, but not distal, small intestine. This is the location of a unique membrane form of a folate hydrolase. This membrane folate hydrolase and its location are necessary in human nutrition because humans require folate, and the folate in foods is poly-gamma-glutamated. Polyglutamated folates cannot be taken into the cells by folate-transporter systems. The ability to take up folate from foods requires the membrane folate hydrolase to sequentially remove the gamma-linked glutamates, freeing folate that can then be transported. PSM antigen has a similar folate hydrolase activity. Others have reported finding an enzyme in the rat brain that functions as an alpha-neurocarboxypeptidase and acts on the abundant brain peptide N-acetylaspartylglutamate to generate glutamate and N-acetylaspartate. The 3'-end of the rat brain enzyme had 84% sequence homology with PSM antigen. Because this enzyme liberates glutamate in the brain, the enzyme is considered to have regulatory activity related to glutamate receptors. Current investigations are underway to determine whether glutamate receptors are present in prostate. Thus, PSM antigen is a unique folate hydrolase-carboxypeptidase that can release glutamate with either gamma-or alpha-linkage. Its enzymatic activity raises a number of questions for consideration. In the normal prostate where the protein is intracellular, is PSM' antigen keeping folate in nonglutamated forms? If so, folate should be able to readily diffuse out of prostate cells, making the prostate gland an organ at risk for localized folate deficiency and carcinogenesis. In prostate tumor cells, with the enzyme outside of the cell, can PSM antigen be used for the activation of cytotoxic prodrugs?
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PMID:Characterization and glutamyl preferring carboxypeptidase function of prostate specific membrane antigen: a novel folate hydrolase. 912 29

The toxicity of two conjugates containing ribosome-inactivating proteins (RIPs, i.e. saporin and ricin-A chain x-linked to transferrin) has been measured on a prostatic cancer line (PC3) naturally overexpressing the transferrin receptor, in the presence of monensin and chloroquine. This paper investigates whether the increased toxicity of Tf-RIPs induced by monensin and chloroquine may be due to alterations of the normal endocytotic pathway of the complexes mediated by the transferrin receptor. Monensin, besides inducing alkalinization of normally acid intracellular compartments, causes an accumulation of the receptor-bound Tf-RIP in a perinuclear region contiguous to the cisternae of the trans-Golgi network. Chloroquine, though increasing the intracellular pH, seems not to modify the endocytotic pathway of these chimeric molecules. We believe that the enhanced toxicity of the Tf-RIPs may be related to intracellular alkalinization (i.e., endosomal or lysosomal pH) rather than to the effects on the recycling of transferrin receptor-bound toxins. We conclude that the efficacy of chimeric toxins may be modulated not only by the carrier used for their engineering but also by addition of drugs able to influence the stability and activation of the toxins inside the cell.
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PMID:The effect of monensin and chloroquine on the endocytosis and toxicity of chimeric toxins. 976 Sep 93

Transferrin, an abundant bone marrow constituent, has been shown to be a potent mitogen in vitro in the prostate cancer cell line PC3. T4 (L-thyroxine) and T3 (3',3,5-tri-iodo-L-thyronine) are regulators of cell metabolism. In this study, the effects of nonphysiological concentrations (about two orders of magnitude higher) of T4, T3, T2 (3,5-di-iodo-L-thyronine), RT3 (reverse T3, 3',5', 3-tri-iodo-L-thyronine) and transferrin (about three orders of magnitude lower) were tested on the prostate cancer cell lines PC3, DU145 and LNCaP, and the breast cancer cell line MCF-7. In PC3 cells, increased proliferation by transferrin could be reversed by the addition of T3 or T4. T4 decreased proliferation in all cell lines tested, while transferrin increased proliferation in PC3 cells only. T3 decreased proliferation in PC3, LNCaP and MCF-7 cells but had no effect on DU145 cells. T4 and T3 gave two-state behavior in LNCaP cells. These results were combined to determine the essential iodines which produced the observed proliferative effects. Cell lines responded differently to T4, T3, T2, RT3 and transferrin suggesting a specific interaction among the compounds tested and the different cell lines. Finally, regulation of gene expression was demonstrated using DU145 cells. Upregulation of c-fos mRNA was observed in cultures at early time-points in the presence of T4, transferrin or both. Decreased expression was observed at later time-points with no expression at 4 h. An explanation for these results may be a change in thyroid hormone receptor/ligand affinity. Thus, the interactions between thyroid hormones and cancer cells may be different from those between thyroid hormones and normal cells.
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PMID:Altered response to thyroid hormones by prostate and breast cancer cells. 1066 23

Insulin-like growth factor (IGF)-binding protein-3 (IGFBP-3) possesses both growth-inhibitory and -potentiating effects on cells that are independent of IGF action and are mediated through specific IGFBP-3 binding proteins/receptors located at the cell membrane, cytosol, or nuclear compartments and in the extracellular matrix. We have here characterized transferrin (Tf) as one of these IGFBP-3 binding proteins. Human serum was fractionated over an IGFBP-3 affinity column, and a 70-kDa protein was eluted, sequenced, and identified (through database searching and Western immunoblot) as human Tf. Tf bound IGFBP-3 but had negligible affinity to the other five IGFBPs, and iron-saturated holo-Tf bound IGFBP-3 more avidly than unsaturated Tf. Biosensor interaction analysis confirmed that this interaction is specific and sensitive, with a high association rate similar to IGF-I, and suggested that binding occurs in the vicinity of the IGFBP-3 nuclear localization site. As an independent confirmation of this interaction, using a yeast two-hybrid system, we cloned Tf from a human liver complementary DNA library as an IGFBP-3 protein partner. Tf treatment blocked IGFBP-3-induced cell proliferation in bladder smooth muscle cells, and IGFBP-3-induced apoptosis in prostate cancer cells. In summary, we have employed a combination of techniques to demonstrate that Tf specifically binds IGFBP-3, and we showed that this interaction has important physiological effects on cellular events.
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PMID:Transferrin is an insulin-like growth factor-binding protein-3 binding protein. 1129 22


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