Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gonadotropin releasing hormone is a hypothalamic decapeptide that stimulates the release of gonadotropic hormones from the anterior pituitary gland. Therapeutically, the human pituitary GnRH receptor is the target of agonists used in the suppression of prostate cancer. Here we report the isolation of a cDNA representing this receptor. It encodes a protein with a transmembrane topology similar with that of other G protein-coupled, 7-transmembrane receptors. Binding studies of the cloned receptor demonstrate high affinity and pharmacological properties similar with the native human pituitary GnRH receptor. Northern blot and reverse transcriptase/PCR analysis revealed that its mRNA is expressed in pituitary, ovary, testis, breast, and prostate but not in liver and spleen. Availability of a human GnRH receptor cDNA should permit the design of improved analogs for therapeutic applications.
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PMID:Cloning, sequencing, and expression of human gonadotropin releasing hormone (GnRH) receptor. 133 90

A highly sensitive nested reverse transcriptase-PCR assay, with primers derived from the prostate-specific antigen (PSA) and prostate-specific membrane antigen (PSM) cDNA sequences, has been used to detect occult hematogenous micrometastatic prostate cells. In 77 patients with prostate cancer, PSM and PSA primers detected circulating prostate cells in 48 (62.3%) and 7 (9.1%) patients, respectively. In treated stage D disease patients, PSM primers detected cells in 16 of 24 patients (66.7%), while PSA primers detected cells in 6 of 24 (25%). In post-radical prostectomy patients with negative serum PSA values, PSM primers detected metastases in 21 of 31 patients (67.7%), whereas PSA primers detected cells in only 1 of 33 (3.0%), indicating that micrometastatic spread may be a relatively early event in prostate cancer. The analysis of 40 individuals without known prostate cancer provides evidence that this assay is highly specific and suggests that PSM expression may predict the development of cancer in patients without clinically apparent prostate cancer. Using PSM primers, we detected micrometastases in 4 of 40 controls, 2 of whom had known benign prostatic hyperplasia and were later found to have previously undetected prostate cancer. The clinical significance of detection of hematogenous micrometastic prostate cells using PSM primers and potential applications of this molecular assay, as well as the assay for PSA, merit further study.
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PMID:Sensitive nested reverse transcription polymerase chain reaction detection of circulating prostatic tumor cells: comparison of prostate-specific membrane antigen and prostate-specific antigen-based assays. 752 94

Prostate-specific antigen (PSA) is considered a highly specific biochemical marker of the prostate gland and is currently used for prostate cancer diagnosis and monitoring of patients with prostate adenocarcinoma. We recently demonstrated, however, that about 30% of female breast tumors produce a M(r) 33,000 protein that has striking similarities to seminal PSA. In this study we characterized the presence of PSA in 6 breast tumors and in the testosterone-stimulated T47D breast cancer cell line at the mRNA level. Using reverse transcriptase-polymerase chain reaction and DNA sequencing techniques we identified PSA mRNA in immunoreactive PSA-positive breast tumors but not in immunoreactive PSA-negative breast tumors. The sequence of the generated polymerase chain reaction products was identical to the sequence of the PSA complementary DNA derived from prostate tissue. The data presented here support the notion that breast tumors produce a M(r) 33,000 protein which is identical to PSA produced by the prostate gland. Our study suggests that the presence of PSA in breast tumors may be used as a new additional biochemical marker for breast cancer prognosis, for the spreading of hematogenous micrometastases, and/or for response to adjuvant treatment.
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PMID:Molecular characterization of prostate-specific antigen messenger RNA expressed in breast tumors. 752 95

Current imaging modalities used to stage prostate cancer clinically fail to detect extracapsular disease in a significant subset of patients. A molecular based peripheral blood assay using the reverse transcriptase polymerase chain reaction has recently been shown to be a highly sensitive staging modality for detecting extraprostatic disease preoperatively. The assay uses primers that are specific for prostate specific antigen (PSA). We compare the application of the reverse transcriptase polymerase chain reaction assay using primers specific for the human prostate specific membrane antigen with results obtained from the same specimens by reverse transcriptase polymerase chain reaction for PSA. Prostate specific membrane antigen, a recently cloned prostatic antigen, is a transmembrane glycoprotein that has been described as prostate specific. These assays were applied to ribonucleic acids extracted from the peripheral blood lymphocyte fraction of 80 patients with clinically localized prostate cancer. In addition, blood specimens from 20 female patients, 20 young male patients, 25 age-matched control men under treatment for benign prostatic hypertrophy and 20 men with established, untreated metastatic prostate cancer were tested. All 3 groups of noncancer patients had negative polymerase chain reactions for PSA as well as prostate specific membrane antigen. Of 20 metastatic prostate cancer patients 16 (80%) had positive polymerase chain reactions for PSA, while only 10 (50%) had positive results for prostate specific membrane antigen. Among the 80 patients with clinically localized disease (stages T1 to T2cN0M0), 27 and 19 had positive polymerase chain reaction for PSA and prostate specific membrane antigen, respectively, from blood specimens obtained preoperatively. Analyzing the final pathology in each patient with the reverse transcriptase polymerase chain reaction assay identified a significantly stronger correlation with tumor invasion using the results of the PSA test rather than the results of the prostate specific membrane antigen reverse transcriptase polymerase chain reaction test (67% versus 34% sensitivity for detecting capsular penetration, 87% versus 46% sensitivity for detecting disease to the surgical margin and 83% versus 16% sensitivity for detecting seminal vesicle invasion). In contrast to the reverse transcriptase polymerase chain reaction assay for PSA, a similar assay done for prostate specific membrane antigen did not correlate with pathological stage of prostate cancer.
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PMID:Molecular staging of prostate cancer. II. A comparison of the application of an enhanced reverse transcriptase polymerase chain reaction assay for prostate specific antigen versus prostate specific membrane antigen. 753 52

We report that growth of LNCaP human prostate cancer cells is significantly stimulated (up to 120% above control) by physiological estradiol (E2) concentrations. This growth increase appears to be comparable to that induced by either testosterone or dihydrotestosterone, as also reported by others. This paper presents novel illustrative evidence for estrogen-binding proteins and messenger RNA transcripts in LNCaP cells. In fact, 1) the reverse transcriptase-polymerase chain reaction system documented normal messenger RNA for estrogen receptors (ER); 2) the radioligand binding assay allowed the detection of high affinity, reduced capacity binding sites in both soluble and nuclear cell fractions; and 3) the immunocytochemical analysis showed a consistently intensive staining for both ER and progesterone receptors. Compared to other human estrogen-responsive mammary cancer cells, MCF7 and ZR75-1, ER expression in LNCaP cells was not significantly lower, as shown by levels of the ER transcripts, number of sites per cell, or femtomoles per mg DNA as well as the percentage and intensity of immunocytochemical staining. A relative estimate of ER expression obtained by matching LNCaP with another human prostate cancer cell line, PC3, always displayed significantly and consistently higher levels in LNCaP cells. The detection of relatively high type I ER content in either cell compartment of LNCaP cells was paralleled by a highly intensive staining for progesterone receptors. In addition, evidence that the synthetic androgen R1881 did not compete for type I binding of E2 and that any E2-induced growth was completely reversed by the pure antiestrogen ICI-182,780, but unaffected by the antiandrogen Casodex, clearly suggests that the biological response of LNCaP cells to E2 is mediated via its own receptor.
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PMID:Growth of LNCaP human prostate cancer cells is stimulated by estradiol via its own receptor. 753 68

CD44 is a glycosylated adhesion molecule which may undergo alternative splicing of 10 possible exons to generate variant isoforms. A number of CD44 variant isoforms expressed by tumor cells have been correlated with metastatic and proliferative behavior. In this study, we have characterized CD44 isoform expression on three prostate cancer cell lines: ALVA-31, PPC-1, and LNCaP. Using reverse transcriptase-polymerase chain reaction, we have found that ALVA-31 and PPC-1 cells express multiple CD44 isoforms, including CD44s (standard form), CD44E (epithelial form), and an exon 14-containing form. In addition, two smaller forms have been detected: one using an alternative donor splice site within exon 5, and a novel form omitting exon 5 entirely. The CD44 isoforms expressed by ALVA-31 and PPC-1 cells appear to be preferentially located on the cell surface. By contrast, LNCaP cells do not express any of the CD44 forms at the RNA or protein level. Both PPC-1 and ALVA-31 cells display tumorigenesis and invasiveness in nude mice, whereas LNCap cells exhibit a less malignant phenotype, suggesting a correlation between CD44 variant (CD44v) expression and aggressive prostate tumor behavior. Functional characterization reveals that CD44 mediates prostate cell adhesion to extracellular hyaluronic acid (HA). In addition, the CD44 cytoplasmic domain binds specifically to ankyrin, a membrane cytoskeletal protein. Double immunofluorescence labeling and confocal microscopic analyses indicate that HA binding induces the HA receptor (i.e., CD44) to form capped structures. Importantly, intracellular ankyrin is preferentially accumulated underneath HA receptor-capped structures. These results suggest that cytoskeletal proteins such as ankyrin are closely associated with CD44-mediated signaling events induced by HA. Finally, HA-mediated transmembrane interactions between CD44 isoforms and cytoskeletal proteins (i.e. ankyrin) may play a pivotal role in regulating tumor cell behavior during human prostate cancer development.
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PMID:Interaction of CD44 variant isoforms with hyaluronic acid and the cytoskeleton in human prostate cancer cells. 754 57

While performing reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of total mRNA from prostate cancer specimens, two forms of PSP94 cDNA were detected. RT-PCR products were analysed by Southern blotting and probing with exon-specific oligonucleotides. In the short form of PSP94 mRNA, designated as PSP57, exon III was found to be deleted. The two mRNA forms were confirmed by cloning and sequencing of the RT-PCR products and were found to result from alternative splicing. The alternatively spliced form, PSP57, was characterized by sequence analysis. PSP94 and PSP57 possess identical exons I and II, including identical secretion signal peptide and the 5' untranslated sequences. PSP57 has a frame-shifted exon IV and encodes a putative 57 amino acid protein with a novel, highly basic C-terminus of 41 amino acids. PSP57 mRNA was detected in other urogenital tissues (kidney, bladder) and in most tumor cell lines tested, but was not detectable in other tissues such as breast and lung. In prostate tumor cell lines, PSP57 mRNA was aberrantly spliced and localized in the nuclear fraction of the cell. Our results suggest the possible existence of a novel PSP protein that originates from alternative splicing of PSP94 mRNA in urogenital tissues.
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PMID:Alternative splicing of PSP94 (prostatic secretory protein of 94 amino acids) mRNA in prostate tissue. 756 62

The expression of prostatic acid phosphatase (PAcP) in three human prostate carcinoma cell lines including LNCaP, DU 145 and PC-3, was studied to explore its potential role as a marker in the progression of prostate cancer. Although Southern blot analysis suggested the presence of PAcP gene in all three prostate carcinoma cell lines, the Northern blot analysis and the reverse transcriptase-polymerase chain reaction (RT-PCR) assay showed that PAcP mRNA can be detected only in LNCaP cells. As one of the major differences between LNCaP cells and PC-3 as well as DU 145 cells is the androgen-sensitivity of LNCaP cells, we then focused on the influence of PAcP expression by the presence of androgen receptor (AR) in human AR cDNA-transfected PC-3 cells and high passages of LNCaP cells. The results demonstrated that the transfection of human AR cDNA into PC-3 cells did not have any detectable effect on the expression of PAcP. Further, in LNCaP cells, while the level of PAcP mRNA diminished upon passage, the AR mRNA level remained approximately the same. Together, these data suggested that the differential expression of PAcP in different prostate carcinoma cells including high passages of LNCaP cells may occur at the transcriptional level and may have little linkage to the expression of AR.
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PMID:The expression of prostatic acid phosphatase is transcriptionally regulated in human prostate carcinoma cells. 764 50

We have developed a highly sensitive method for detecting prostate cancer cells using reverse transcriptase-polymerase chain reaction (RT-PCR) with primers specific for prostate-specific antigen gene. Forty-four lymph nodes obtained from 22 patients with prostate cancers were analyzed by RT-PCR to detect metastatic prostate cancer cells. RT-PCR could detect prostate-specific antigen mRNA in five lymph nodes with histologically and/or immunohistochemically identifiable metastases and in four lymph nodes with negative histological and immunohistochemical analyses for metastases. RT-PCR was a more sensitive method than histology and immunohistochemistry in detecting metastatic prostate cancer cells and could be applied for diagnosing micrometastases of prostate cancer to lymph nodes. This highly sensitive RT-PCR will be a relevant tool to allow a more accurate clinical assessment of lymph node metastases of prostate cancer and to understand lymphatic dissemination of prostate cancer biologically.
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PMID:Detection of micrometastatic prostate cancer cells in lymph nodes by reverse transcriptase-polymerase chain reaction. 769 38

Significant inhibition of proliferative activity in PC3 human prostate cancer cells by estradiol is reported, accompanied by experimental evidence for a specific estrogen receptor (ER). Radioligand-binding assays revealed the presence of high affinity sites of estrogen binding in the nuclear compartment of PC3 cells. In addition, using a reverse transcriptase-polymerase chain reaction system, we obtained evidence of either normal or a variant ER mRNA; the latter, which lacks the entire exon 4, is coexpressed with normal ER mRNA and has been recently characterized in our laboratories. The likelihood that the inhibitory effect exerted by estradiol could be mediated by an increase of transforming growth factor beta (TGF beta) production was also investigated. Use of monoclonal antibodies against TGF beta 1 produced a 3-fold increase of growth rate in PC3 cells; this clearly speaks for high levels of endogenous TGF beta 1. This effect was almost completely abolished after addition of 100 nM estradiol. However, we failed to demonstrate any increase of TGF beta 1 mRNA after estradiol administration using Northern blot analysis. Further studies are needed to ascertain whether the estradiol-induced growth inhibition of PC3 cells is either mediated by other TGF beta species or exerted via alternative mechanism(s).
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PMID:Estradiol inhibits growth of hormone-nonresponsive PC3 human prostate cancer cells. 811 4


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