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)

We attempted to determine whether beta1,3-galactosyltransferase beta3Gal-T5 is involved in the biosynthesis of a specific subset of type 1 chain carbohydrates and expressed in a cancer-associated manner. We transfected Chinese hamster ovary (CHO) cells expressing Fuc-TIII with beta3Gal-T cDNAs and studied the relevant glycoconjugates formed. beta3Gal-T5 directs synthesis of Lewis type 1 antigens in CHO cells more efficiently than beta3Gal-T1, whereas beta3Gal-T2, -T3, and -T4 are almost unable to direct synthesis. In the clone expressing Fuc-TIII and beta3Gal-T5 (CHO-FT-T5), sialyl-Lewis a synthesis is strongly inhibited by swainsonine but not by benzyl-alpha-GalNAc, and sialyl-Lewis x is absent, although it is detected in the clones expressing Fuc-TIII and beta3Gal-T1 (CHO-FT-T1) or Fuc-TIII and beta3Gal-T2 (CHO-FT-T2). Endo-beta-galactosidase treatment of N- glycans prepared from clone CHO-FT-T5 releases (+/-NeuAcalpha2-->3)Galbeta1-->3[Fucalpha1-->4]GlcNAcbeta1-->3Gal but not GlcNAcbeta1-->3Gal or type 2 chain oligosaccharides, which are found in CHO-FT-T1 cells. This result indicates that beta3Gal-T5 expression prevents poly-N-acetyllactosamine and sialyl-Lewis x synthesis on N-glycans. Kinetic studies confirm that beta3Gal-T5 prefers acceptors having the GlcNAcbeta1-->3Gal end, including lactotriosylceramide. Competitive reverse transcriptase mediated-polymerase chain reaction shows that the beta3Gal-T5 transcript is expressed in normal colon mucosa but not or poorly in adenocarcinomas. Moreover, recombinant carcinoembryonic antigen purified from a CHO clone expressing Fuc-TIII and beta3Gal-T5 reacts with anti-sialyl-Lewis a and carries type 1 chains on oligosaccharides released by endo-beta-galactosidase. We conclude that beta3Gal-T5 down-regulation plays a relevant role in determining the cancer-associated glycosylation pattern of N-glycans.
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PMID:beta 1,3-Galactosyltransferase beta 3Gal-T5 acts on the GlcNAcbeta 1-->3Galbeta 1-->4GlcNAcbeta 1-->R sugar chains of carcinoembryonic antigen and other N-linked glycoproteins and is down-regulated in colon adenocarcinomas. 1105 88

To determine whether the tumor cell contamination of peripheral blood stem cells influences clinical impacts on high-dose chemotherapy in patients with metastatic breast cancer, we analyzed carcinoembryonic antigen (CEA) mRNA in the apheresis products by nested RT-PCR (reverse transcriptase-polymerase chain reaction). A total of 38 metastatic breast cancer patients and ten normal healthy subjects as a negative control were included. Twenty out of 38 (51.3%) apheresis products from patients with metastatic breast cancer were positive for CEA mRNA. CEA mRNA was noted in 54.8% (17/31) of patients mobilized with chemotherapy plus G-CSF and 42.8% (3/7) of patients with G-CSF alone. There was no significant difference in age, estrogen receptor, menopausal status, mobilization method, disease free interval, or number of metastasis sites (1 vs > or = 2) between positive and negative groups. The presence of CEA mRNA in apheresis products did not influence the time to progression and overall survival in both groups. However, both the univariate and the multivariate analysis disclosed that the number of metastasis was associated with survival significantly. We suggest that the tumor cell contamination does not predict poor treatment outcome in patients with metastatic breast cancer.
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PMID:Clinical impacts of tumor cell contamination of hematopoietic stem cell products in metastatic breast cancer patients undergoing autologous peripheral blood stem cell transplantation: multicenter trial. 1130 43

Laparoscopic surgery for treatment of colorectal cancer has been suggested to enhance tumor dissemination. Recently, molecular techniques have been developed to detect micrometastatic disease in patients with solid tumors, with a higher accuracy than cytologic or immunohistochemical approaches. This study was undertaken to investigate the potential harmful effects of laparoscopic-assisted colectomy on neoplastic cell mobilization in patients with resectable colorectal cancer. Fifty patients with nonmetastatic colorectal cancer were randomly assigned to laparoscopic-assisted (LAC, n = 26) or open (OC, n = 24) colectomy. Peripheral venous blood samples were obtained preoperatively, immediately after tumor removal, and 24 hours later. In 10 patients from each treatment group, portal blood and peritoneal fluid samples were also obtained before and after resection. Neoplastic cells were detected by means of reverse transcriptase-polymerase chain reaction targeted to carcinoembryonic antigen (CEA) transcription. CEA mRNA was detected in peripheral venous blood samples from 35 of 50 colorectal cancer patients preoperatively. Among those 15 baseline-negative patients, four experienced conversion 24 hours after tumor resection (2 [33%] of 6 in the LAC group vs. 2 [22%] of 9 in the OC group; NS). At that time point, clearance of CEA mRNA expression was observed in 14 of the 35 baseline-positive patients (9 [45%] of 20 in the LAC group vs. 5 [33%] of 15 in the OC group; NS). In addition, only one patient in the LAC group with baseline-negative CEA mRNA expression experienced portal blood conversion after tumor removal, although his peripheral blood level remained negative. Finally, baseline peritoneal fluid CEA mRNA expression was never detected, but one patient in each group became positive postoperatively. These results confirm that preoperative and perioperative mobilization of neoplastic cells is a frequent occurrence in patients with colorectal cancer, but the surgical approach (LAC vs. OC) does not seem to be a determining factor.
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PMID:Laparoscopic-assisted vs. open colectomy for colorectal cancer: influence on neoplastic cell mobilization. 1130 50

Detection of breast cancer micrometastases based on specific genetic markers may provide useful information to justify appropriate therapeutic strategies. We examined the presence of a carcinoembryonic antigen (CEA) messenger RNA(mRNA) in the peripheral blood of 32 patients with varying stages of breast cancers by means of the reverse transcriptase-polymerase chain reaction (RT-PCR) assay prior to and after the curative operation. CEA mRNA were detected in the peripheral blood samples from 12 (38%) out of 32 breast cancer patients prior to surgery. Among 12 CEA mRNA-positive patients prior to surgery, 4 (33.3%) relapsed from breast cancer within 2 years after surgery. Moreover, CEA mRNA was detected in the peripheral blood samples obtained prior to surgery in 3 out of 11 patients (27.2%) with a stage I disease. One out of three of these patients had a relapse in lung. There were four patterns of CEA mRNA expression, ( +, + ), (+, -), (-, + ), and (-, -) in the pre- and post-operative blood samples. In 12 CEA mRNA-positive patients submitted to surgical resection of the primary tumor, persistence of CEA mRNA expression was observed in five patients (+, +) within a month after surgical treatment. Three out of these 5 patients (60%) relapsed from breast cancer within 2 years after surgery. In 7 other patients (+, -), CEA mRNA expression was not detected within a month after tumor removal, and recurrence occurred in 1 out of the 7 patients (14%) within 2 years after surgery. In 19 patients, CEA mRNA expression was not detected in pre- or post-operative blood samples (-, -). There was a patient whose blood sample was negative for CEA mRNA before the operation, but changed to show a positive result after surgery (-,+). No recurrence was found in 20 of CEA mRNA-negative patients prior to surgery (-, +), (-, -). This study suggested that the presence of CEA mRNA expression in preoperative peripheral blood sample represent the progression of the disease, especially the risk of hematogenous metastasis in the patients in spite of their clinical stage, and the presence of CEA mRNA in the postoperative blood sample may represent the evidence of a residual disease. Thus consideration might be given for adding combined multi-modal therapy.
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PMID:Clinical significance of circulating cancer cells in peripheral blood detected by reverse transcriptase-polymerase chain reaction in patients with breast cancer. 1131 30

Molecular analysis of microdissected tissue samples is used for analyzing tissue heterogeneity of histological specimens. We have developed a rapid one-step microdissection technique, which was applied for the selective procurement of tissue areas down to a minimum of 10 cell profiles. The special features of our microdissection system consist of an ultrasonically oscillating needle and a piezo-driven micropipette. The validity of this technique is demonstrated in human lung large-cell carcinoma by real-time quantitative reverse transcriptase-polymerase chain reaction assays of vimentin, cyclin D1, and carcinoembryonic antigen after linear RNA amplification. mRNA expression values of microdissected samples scattered around those of bulk tumor tissue and showed differential mRNA expression between samples of tumor parenchyma and supportive stromal cells for vimentin and carcinoembryonic antigen as confirmed by immunohistochemistry. In conclusion, this procedure requires simple equipment, is easily performed, and delivers microdissected tissue samples of oligocellular clusters suitable for further molecular analysis.
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PMID:A new method for histological microdissection utilizing an ultrasonically oscillating needle: demonstrated by differential mRNA expression in human lung carcinoma tissue. 1139 75

The histological diagnosis of hepatocellular carcinoma (HCC) can be complicated by difficulty in differentiation from cholangiocarcinoma and metastatic carcinoma. Immunohistochemical stains currently in use are suboptimal in terms of specificity and sensitivity. Using cDNA array analysis for differential gene expression, we demonstrated a significant increase in mRNA expression level of CD10/CALLA, a type 2 cell-surface metalloproteinase, in HCC, which was subsequently confirmed by reverse transcriptase-polymerase chain reaction and Western blotting analysis. To test the possibility of using CD10/CALLA as a diagnostic marker for HCC, various intrahepatic tumors were studied immunohistochemically using a monoclonal antibody for CD10. A characteristic canalicular-staining pattern was observed in normal hepatocytes and at the apical surface of bile duct epithelial cells. The canalicular expression of CD10 was identified in 9 of 15 HCCs examined (60%), whereas 10 cholangiocarcinomas and 8 of 9 metastatic carcinomas lacked this staining. In three of the six HCCs negative for CD10, the surrounding nonneoplastic liver tissue was also negative, suggesting fixation-associated loss of immunoreactivity. Six HCCs had stronger CD10 staining in tumor cells when compared to the surrounding nonneoplastic tissue. Three cases of benign bile duct adenomas also expressed CD10 at the luminal aspect. One of the MCs showed a diffuse, cytoplasmic staining for CD10, a pattern readily distinguishable from that of HCC. A panel of other immunohistochemical markers were also studied for comparison, including polyclonal anti-carcinoembryonic antigen, cytokeratin (CK) 7, CK20, and alpha-fetoprotein. Our results demonstrate that cDNA arrays can be effectively used to identify new diagnostic markers, and that CD10 is a reliable marker for identifying HCC, particularly when used in conjunction with a panel of immunohistochemical markers (polyclonal anti-carcinoembryonic antigen, CK7, CK20, and alpha-fetoprotein) and in the distinction from cholangiocarcinoma.
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PMID:cDNA arrays and immunohistochemistry identification of CD10/CALLA expression in hepatocellular carcinoma. 1158 69

We applied novel real-time reverse transcriptase-polymerase chain reaction (RT-PCR) with a LightCycler for quantitative detection of carcinoembryonic antigen (CEA) mRNA expressing tumor cells in the peripheral blood of colorectal cancer patients. Analysis of peripheral blood samples from 99 potentially curative colorectal cancer patients revealed a significantly higher mean CEA mRNA value in post-operative bloods (18.71) than in pre-operative blood (1.03) (P=0.003). Kaplan-Meier analysis demonstrated disease free survival of patients with positive CEA mRNA in post-operative blood to be significantly shorter than in cases negative for CEA mRNA (P=0.03). These results suggest that tumor cells could be shed into the bloodstream during surgical procedures, and these free tumor cells are accompanied by a poor patient outcome. Real-time quantitative RT-PCR is a useful technique for quantitative assessment of free tumor cells in the peripheral blood of colorectal cancer patients.
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PMID:Quantitative detection of CEA expressing free tumor cells in the peripheral blood of colorectal cancer patients during surgery with real-time RT-PCR on a LightCycler. 1206 95

We conducted a study to compare the expression of human mammaglobin (hMAM) mRNA in breast cancer patients' peripheral blood with serum carcinoembryonic antigen (CEA) and CA 15.3. A total of 33 metastatic breast cancer patients were enrolled. The blood samples were used to test the expression of hMAM mRNA by reverse transcriptase polymerase chain reaction (RT-PCR) and CEA, CA 15.3 by radioimmunoassay. The serum CEA and CA 15.3 levels were elevated in 17 (51%) and 23 (69%) of the patients, respectively. When combined CEA with CA 15.3, the sensitivity rate raised to 78%. hMAM mRNA was detected in 18 (54%) of the 33 patients. When combined hMAM mRNA with CEA or CA 15.3, the sensitivity rate were 81% and 90%, respectively (P=0.045). In conclusion, the hMAM mRNA RT-PCR can be an adjunct in detecting metastatic breast cancer.
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PMID:The expression of mammaglobin mRNA in peripheral blood of metastatic breast cancer patients as an adjunct to serum tumor markers. 1260 14

Peritoneal recurrence after curative resection of malignant tumor with negative cytology is considered to be caused by microscopic dissemination of the exfoliated cancer cells from primary tumors to serosal surfaces at the time of operation, not detectable with conventional diagnostic tools. We applied the reverse transcriptase-polymerase chain reaction (RT-PCR) for carcinoembryonic antigen (CEA) and cytokeratin 20 (CK 20) to detect micrometastatic foci in the peritoneal cavity of colon cancer patients. Cytological samples taken by peritoneal lavage from a series of 79 colon cancer patients were analyzed microscopically, for CEA levels, and by RT-PCR analysis using nested primers for CEA and CK 20. Cases with both CEA and CK 20 signals were defined as PCR-positive. This RT-PCR method proved both sensitive (1 tumor cell/10(6) non-tumor cells on preparation of serial colorectal cancer cell dilutions) and specific (no false positive results, 0/23 tested in our control experiment). Intraperitoneal micrometastatic cells were detected in peritoneal lavage 7.6% by cytology, 17.7% by CEA levels, and 24.1% by RT-PCR (significantly higher than by cytology: p=0.0046). RT-PCR detection rate increased in parallel with pathological depth of tumor invasion, and also a pathological stage-dependence was suggested according to the tumor-node-metastasis classification of the International Union Against Cancer. Our results suggest that CEA and CK 20 mRNA identification by RT-PCR appeared to be reliable and may be useful for early diagnosis in peritoneal dissemination of colon cancer.
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PMID:Detection of peritoneal micrometastases by reverse transcriptase-polymerase chain reaction targeting carcinoembryonic antigen and cytokeratin 20 in colon cancer patients. 1263 2

The current authors previously identified circulating cells expressing carcinoembryonic antigen (CEA) messenger ribonucleic acid (mRNA) in 80% of lung cancer patients bearing distant metastases. The current study prospectively validated the data on a novel cohort and extended the study to other mRNAs expressed by neoplastic cells. CEA, cytokeratin 19 and 20, aldolase A and epithelial glycoprotein 2 (EPG2) mRNA was analysed by reverse transcriptase-polymerase chain reaction in circulating cells from 19 healthy controls, and in biopsies and blood at diagnosis from 32 lung cancer patients monitored for 24 months. Aldolase A and cytokeratin 19 mRNA occurred in circulating cells of all controls; cytokeratin 20 was not expressed by any lung cancer biopsy. EPG2 mRNA occurred in all biopsies but not in the patients' circulating cells. CEA mRNA occurred in 29/32 (90.6%) biopsies and in 17/32 mRNA samples from circulating cells from lung cancer patients. Of these positive patients 12/17 developed metastases within 9 months of mRNA analysis. Three positive patients died, one was lost to follow-up, and one did not develop metastases within 24 months. Of the negative patients 12/15 did not develop metastases during the 24-month follow-up; one patient was lost to follow-up, one did not express CEA, and another developed metastases. Unlike in other neoplasias, cytokeratin 19 and 20, aldolase A and epithelial glycoprotein 2 messenger ribonucleic acid are not useful for the detection of circulating cancer cells in lung cancer. Carcinoembryonic antigen messenger ribonucleic acid analysis in circulating cells helps to identify lung cancer patients at a greater risk of metastases.
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PMID:Carcinoembryonic antigen mRNA analysis detects micrometastatic cells in blood from lung cancer patients. 1451 29


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