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)

Prostate cancer is the most common malignant disease in men in western societies. Extracapsular spread of carcinoma is found in approximately half of the patients that are treated by radical prostatectomy. Recently, a new prostate-specific membrane glycoprotein was cloned and sequenced. A highly sensitive and specific nested reverse transcriptase polymerase chain reaction has been developed to detect early occult haematogeneous micrometastatic prostate cells. We analysed venous samples from 17 patients with metastatic prostate cancer using a modified reaction assay. This showed presence of micrometastatic prostate cells in 14 patients. Molecular detection of circulating prostatic epithelial cells could improve clinical staging and treatment of early prostate cancer.
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PMID:[Prostate-specific membrane antigen. A new sensitive molecular indicator in metastasizing prostatic cancer]. 863 73

Certain osteoclastic markers (multinucleation and tartrate-resistant acid phosphatase) were induced in human leukemia HL-60 cells by treatment with 10(-7) M 1,25-dihydroxy-vitamin D3 [1,25(OH)2D3] for 10 days. However, no formation of pits on a bone substrate by vitamin-treated HL-60 cells was detected. Expression of calcitonin receptors (CTR), another osteoclastic marker, was examined by means of the reverse transcriptase polymerase chain reaction. The human CTR-cDNA (T47D isotype) was amplified from untreated HL-60 cells, but not from cells treated with 1,25(OH)2D3. The CTR mRNA disappeared within 24 h after the treatment. Thus, 1,25(OH)2D3-differentiated HL-60 cells failed to show two intrinsic characteristics of osteoclasts, pit formation on a bone substrate and expression of CTR. We then examined the expression of CTR on established human leukemia cell lines. The CTR mRNA was expressed in myeloblastic ML-1 and promyelocytic HL-60 leukemia cells but not in more mature macrophage-like cell lines, U-937 and THP-1 cells. Neither B cell leukemia BALL-1, T cell leukemia Jurkat, promegakaryoblastic leukemia Meg-J, nor cervix uteri carcinoma HeLa S3 cells amplified the CTR products. The cDNA of BIN67-isotype CTR, that has an additional 16-amino acid insert in the putative first intracellular loop of T47D-type CTR [Kuestner et al. (1994) Mol. Pharmacol. 46, 246-255], was amplified by neither strain tested. It was suggested that the T47D-type CTR is a novel differentiation antigen of immature myeloid lineage cells.
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PMID:Expression of calcitonin receptors on human myeloid leukemia cells. 854 84

Amplification of the CCDN1 gene encoding cyclin D1 was examined by Southern blotting and multiplex polymerase chain reaction (PCR) and occurred in 8 of 53 patients (15%) with primary resected non-small-cell lung cancer (NSCLC). These tumours and 17 additional tumours with a normal gene copy number showed overexpression of cyclin D1 (25/53, 47%), as assessed by immunostaining using a monoclonal antibody. In 22/25 cases, cyclin D1 was localised in the cytoplasm, but some (7/25) had simultaneous nuclear staining. This result is in marked contrast to that reported in breast, hepatocellular and colorectal carcinoma studies where immunostaining was invariably nuclear. Examination of a restriction fragment length polymorphic (RFLP) site within the 3'untranslated region of the cDNA following reverse transcriptase (RT)-PCR (29/53 informative cases) showed a strong association between cytoplasmic staining and imbalance in allele-specific message levels. Cyclin D1 overexpression was associated with a poorly differentiated histology (P = 0.04), less lymphocytic infiltration of the tumour (P = 0.02) and a reduction in local relapse rate (P = 0.01). The relative risk of local relapse was 9.1 in tumours without cyclin D1 overexpression (P = 0.01, Cox regression analysis). We conclude that genetic alteration of cyclin D1 is a key abnormality in lung carcinogenesis and may have diagnostic and prognostic importance in the treatment of resectable NSCLC.
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PMID:Prognostic significance of CCND1 (cyclin D1) overexpression in primary resected non-small-cell lung cancer. 856 33

Leukemia inhibitory factor (LIF) is a cytokine that was originally described as a differentiation factor of a murine myeloid leukemia cell line and subsequently found to be an important mediator of embryonic development. Although extensively studied in the hematopoietic system, its effects on solid tumors are generally unknown. In the present study we investigated the role of LIF in human breast cancer cells. Using the reverse transcriptase-polymerase chain reaction, we found that the human breast carcinoma MCF-7 cell line expressed the message for both LIF receptor and its signal-transducing protein gp130, suggesting that these receptors might be biologically active. Binding studies with radiolabeled LIF demonstrated that MCF-7 cells interacted with this cytokine, and the ligand binding was specific and time, dose, and temperature dependent. In addition, a Scatchard analysis of the data revealed a single class of high-affinity (Kd 0.27 nM) receptors with a density of approximately 430 sites per cell. MCF-7 cells exposed to LIF internalized and degraded the ligand. LIF stimulated the growth of MCF-7 as well as other estrogen-dependent and independent breast cancer cell lines, but the effect on normal breast epithelial lines was less significant. Likewise, it stimulated colony formation by breast cancer cells obtained from five different breast cancer patients in a dose-dependent fashion. These results overall suggest that human breast tumor cells express functional LIF receptors that play a role in breast cancer cell proliferation.
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PMID:Leukemia inhibitory factor binds to human breast cancer cells and stimulates their proliferation. 856 13

CD44 isoforms have been implicated in tumor progression and embryogenesis. Primary renal cell tumors (n = 100) of various histopathological differentiation and grading stages were analyzed for expression of CD44 isoforms in comparison with nonmalignant adult and fetal renal tissues. Evaluations were performed by immunohistochemistry using CD44 isoform-specific monoclonal antibodies and by reverse transcriptase polymerase chain reactions (RT-PCR). In the nonmalignant kidney no CD44 variant isoforms were detected. There was a significant increase in expression of CD44 standard (CD44s) and several variant isoforms (CD44v) in the course of tumor differentiation in clear cell carcinomas (n = 68) from stages G1 to G3 (P < 0.0001 for CD44s and isoforms containing CD44-6v, and P < 0.007 for those containing CD44-9v). Also, in chromophilic cell carcinomas (n = 13), CD44 isoform expression correlated with grading; ie, no CD44 expression was detected in G1 tumors, whereas in approximately 50% of the G2 tumors, CD44s, CD44-6v, and CD44-9v isoforms were present. Oncocytomas (n = 8), which are benign renal cell tumors, did not express CD44 isoforms, whereas invasive chromophobe cell carcinomas (n = 11) were positive for CD44s and CD44v isoforms. Transcript analyses by RT-PCR revealed that the upregulated isoforms in the carcinoma cells contained exons 8 to 10 and 3, 8 to 10 in combination from the variant region. In conclusion, expression of variant CD44 isoforms was strongly correlated with grading and appears to mediate a more aggressive phenotype to renal cell tumors.
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PMID:Expression of CD44 isoforms in renal cell tumors. Positive correlation to tumor differentiation. 857 8

We have studied the response to oestrogen and expression of oestrogen receptors in responsive LNCaP and androgen non-responsive PC3 human prostate cancer cell lines. Growth of LNCaP cells is significantly stimulated by physiological concentrations of oestradiol; this growth increase appears to be comparable to that induced by either testosterone or dihydrotestosterone. In contrast, oestradiol significantly inhibits the proliferation of PC3 cells. We also present novel evidence for functional oestrogen binding in LNCaP cells. This evidence was first obtained by means of radioligand binding assays and was further corroborated using: (a) immunocytochemical analysis of oestrogen and progesterone receptors; (b) reverse transcriptase polymerase chain reaction of oestrogen receptor mRNAs; and (c) immunofluorescence of the 27 kDa heat shock protein (Hsp27), which has been reported to be a marker of functional oestrogen receptors. There appeared to be significantly and consistently lower levels of oestrogen receptor expressed in PC3 cells than in LNCaP cells. The observation that oestradiol-induced growth of LNCaP cells is completely reversed by the pure anti-oestrogen ICI 182,780 clearly implies that the biological response of these cells to oestradiol is mediated mainly via its own receptor. On the other hand, use of a neutralizing antibody against transforming growth factor (TGF)-beta 1 results in a remarkable increase in the growth of PC3 cells; this effect is almost completely abolished after the addition of oestradiol. This suggests that the oestradiol-induced growth inhibition may be mediated by TGF-beta 1. These results suggest that the current model for hormone-dependence of human prostatic carcinoma should be revised. This is of special concern, because recent data indicate that prostate cancer has become the most prevalent cancer and the second principal cause of cancer death in western countries.
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PMID:Human prostate cancer: a direct role for oestrogens. 858 3

Testicular germ cell tumors are the most common form of cancer in young adult males. They result from a derangement of primordial germ cells, and they grow out from a noninvasive carcinoma-in-situ precursor. Since carcinoma in situ can readily be cured by low-dose irradiation, there is a great incentive for non- or minimally invasive methods for detection of carcinoma in situ. We have recently shown that human Tera-2 embryonal carcinoma cells, obtained from a nonseminomatous testicular germ cell tumor, show alternative splicing and alternative promoter use of the platelet-derived growth factor alpha-receptor gene, giving rise to a unique 1.5-kb transcript. In this study we have set up a reverse transcriptase-polymerase chain reaction strategy for characterization of the various transcripts for this receptor. Using this technique, we show that a panel of 18 seminomas and II nonseminomatous testicular germ cell tumors all express the 1.5-kb transcript. In addition, a panel of 27 samples of testis parenchyma with established carcinoma in situ were all found to be positive for the 1.5-kb transcript, while parenchyma lacking carcinoma in situ, placenta, and control semen were all negative. These data show that the 1.5-kb platelet-derived growth factor alpha-receptor transcript can be used as a highly selective marker for detection of early stages of human testicular germ cell tumors.
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PMID:Aberrant platelet-derived growth factor alpha-receptor transcript as a diagnostic marker for early human germ cell tumors of the adult testis. 861 Jan 36

To further investigate the possibility for retroviral involvement in the etiology of human breast cancer we processed peripheral blood monocytes and malignant breast tissue biopsies from 10 patients with breast cancer (infiltrating ductal carcinoma or infiltrating lobular carcinoma; ages 40-80 years) and 20 normal healthy women (with no evidence or family history of breast cancer. 10 age-matched controls and 10 women age 22-27 years) for the assay of the retroviral enzyme, reverse transcriptase, using an ELISA and for election microscopy examination for the detection of retroviral-like particles. Reverse transcriptase activity was detected in 5 out of 10 samples of monocyte culture medium and in 1 out of 10 of malignant tissue biopsies from the patients with breast cancer. In contrast, reverse transcriptase was not detected in the culture medium of the monocytes from any of the control subjects. Electron microscopy did not reveal the presence of any retroviral-like particles in any sample of monocyte culture medium or in any of the malignant or normal breast tissue biopsies. Despite evidence for the presence of reverse transcriptase in a subsample of the monocyte culture medium and breast tissue biopsies from the cohort of breast cancer patients who participated in this study, the role of retroviruses in human breast cancer remains unclear.
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PMID:Are retroviruses involved in the aetiology of human breast cancer? 863 60

Alveolar epithelial cells in vivo, primary cultures of adult rat type II cells, and human A549 alveolar carcinoma cells express parathyroid hormone-related protein (PTHrP). Here we demonstrated that type II cells and A549 cells also express the PTHrP receptor and that they exhibit differentiation-related responses to the amino-terminal PTHrP fragment, PTHrP-(1-34). PTHrP receptor expression in A549 cells was shown by detection of a 0.3-kb reverse transcriptase polymerase chain reaction product formed by primers specific for PTHrP receptor. In situ hybridization studies localized the site of production of PTHrP and PTHrP receptor mRNA in rat lung cells with morphology and location typical of type II cells. Primary cultures of such type II cells also expressed PTHrP receptor mRNA. Incubation with PTHrP-(1-34) stimulated disaturated phosphatidylcholine (DSPC) synthesis in A549 cells and increased the release of newly synthesized DSPC by cultured type II cells and A549 cells. In addition, PTHrP-(1-34) increased the number of lamellar bodies per type II cell and increased their expression of alkaline phosphatase in a dose-dependent manner. Thus PTHrP-(1-34) promoted a differentiated type II cell phenotype. Since cultured type II cells, alveolar epithelial cells in vivo, and A549 cells express PTHrP and the PTHrP receptor, PTHrP-(1-34) may be an autocrine regulatory factor in type II cells and lung cancer cells.
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PMID:Parathyroid hormone-related protein, an autocrine regulatory factor in alveolar epithelial cells. 863 27

Tyrosine kinases play central roles in the growth and differentiation of normal and tumor cells. In this study, we have analyzed the general tyrosine kinase expression profile of a prostate carcinoma (PCA) xenograft, CWR22. We describe here an improved reverse transcriptase-PCR approach that permits identification of nearly 40 different kinases in a single screening; several of these kinases are newly cloned kinases and some are novel. According to this, there are 11 receptor kinases, 9 nonreceptor kinases, and at least 7 dual kinases expressed in the xenograft tissue. The receptor kinases include erbB2, erbB3, Ret, platelet-derived growth factor receptor, sky, nyk, eph, htk, sek (eph), ddr, and tkt. The nonreceptor kinases are lck, yes, abl, arg, JakI, tyk2, and etk/bmx. Most of the dual kinases are in the mitogen-activating protein (MAP) kinase-kinase (MKK) family, which includes MKK3, MKK4, MEK5, and a novel one. As a complementary approach, we also analyzed by specific reverse transcriptase-PCR primers the expression profile of erbB/epidermal growth factor receptor family receptors in a variety of PCA specimens, cell lines, and benign prostatic hyperplasia. We found that erbB1, -2, and -3 are often coexpressed in prostate tissues, but not in erbB4. The information established here should provide a base line to study the possible growth and oncogenic signals of PCA.
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PMID:A tyrosine kinase profile of prostate carcinoma. 865 Feb 1


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