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)

A role for human papilloma virus (HPV) infection in the pathogenesis of head and neck neoplasms has gained support in recent years. Expression of two early-region HPV genes, E6 and E7, is widely accepted as essential for viral-induced carcinomas of the genital tract. These oncoproteins interact with the products of the cellular tumor suppressor genes, p53 and retinoblastoma, and inactivate them. Examining E6/E7 transforming gene expression is an important step toward elucidating the pathogenesis of HPV in head and neck neoplasms. We introduce nasal inverted papilloma (IP) as a novel system for evaluating viral genomic expression and transforming gene regulation of tumorigenesis by virtue of its association to HPV infection and potential for malignant progression. We describe here a reverse transcriptase-polymerase chain reaction approach for the detection of HPV E6/E7-specific transcripts in RNA extracted from IR. A primer pair flanking previously mapped HPV 6 E6/E7 splice donor/acceptor sites was used to direct amplification of cDNA. Reverse transcriptase-polymerase chain reaction experiments generated products representing the 1.2 Kb E1E4 splice transcript and a smaller unclassified fragment in IP from two patients. These results provide evidence for HPV 6 E6/E7 expression in IP with the potential to encode transforming proteins.
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PMID:The HPV 6 E6/E7 transforming genes are expressed in inverted papilloma. 952 9

Verruciform xanthoma is an uncommon mucocutaneous condition of uncertain cause that only occasionally affects the skin. The histopathology is distinctive for the presence of foamy histiocytes present within elongated dermal papillae. Although simple excision of intraoral lesions is reportedly curative, treatment of cutaneous lesions has not been previously reported. We describe a 62-year-old man with a large lesion of verruciform xanthoma affecting both inguinal folds. Immunohistochemical staining, reverse transcriptase polymerase chain reaction for human papilloma virus, and ultrastructural analysis were performed to investigate the pathogenesis of this lesion. The results of these studies support the theory that the source of lipid in dermal histiocytes is degenerating keratinocytes. Initial treatment with wire loop electrosection, pulsed dye (585 nm) laser, and x-ray therapy of this patient proved unsuccessful. Preliminary success has been achieved using wide surgical excision with primary closure.
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PMID:Management of cutaneous verruciform xanthoma. 1064 Sep 29

To establish a new predictor of human cervical cancer radioresponse, we investigated the transactivational ability of p53 gene in tumor tissue for use as a marker of both pretreatment and postirradiation levels of mRNA of its downstream gene, WAF1. A total of 38 wild-type p53-bearing patients with histologically proved uterine cervical cancer were treated with definitive radiotherapy. Their p53 status was investigated using a single-strand conformation polymorphism analysis, and human papilloma virus 16, 18, 33, and 58 E6 was determined by polymerase chain reaction in pretreatment biopsy specimens. WAF1 mRNA was estimated by reverse transcriptase-polymerase chain reaction in both pretreatment specimens and those obtained after the administration of 10.8 Gy. Undetectable or low pretreatment levels of WAF1 mRNA were associated with complete response in the majority of cases, whereas only a few patients with a high pretreatment WAF1 level responded to treatment (P = .03). The increase in the postirradiation level of WAF1 mRNA positively correlated with better treatment response and long survival (P = .02). Although the human papilloma virus infection did not change the radiation response directly, it decreased the inducibility of WAF1. Consequently, the lower inducibility of WAF1 resulted in a poor treatment response. This is the first clinical report showing that the transactivational ability of p53 may be a determinant of the efficacy of cervical cancer radiotherapy.
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PMID:Determination of p53-mediated transactivational ability in radiation-treated cervical cancer. 1097 90

Treatment of haematopoietic BA/F3 cells with the thymidylate synthase inhibitor 5-fluoro-2'-deoxyuridine (FUdR) activated apoptosis through a mechanism that required continuous protein synthesis and was inhibited by Bcl-2 over-expression. Analysis of p53 levels in cells treated with FUdR indicated a marked accumulation of this protein. Accumulation of p53 was also observed in cells over-expressing Bcl-2. In BA/F3 cells transfected with a cDNA coding for the human papilloma virus protein E6, p53 accumulation after FUdR treatment was inhibited markedly. However, apoptosis was induced in both control and E6 cells to a similar extent. The role of the CD95/CD95 ligand (CD95L) system in FUdR-induced apoptosis was also assessed. As determined by reverse transcriptase PCR, BA/F3 expressed a low constitutive level of CD95L mRNA, which decreased following FUdR treatment. Moreover, blocking CD95-CD95L interactions with antagonistic CD95 monoclonal antibody did not prevent drug-induced apoptosis. Furthermore, analysis of caspase involvement showed important differences in apoptosis induced by CD95-triggering or FUdR treatment. In summary, these results suggest that apoptosis induced by thymineless stress in haematopoietic BA/F3 cells occurs by a mechanism that does not require accumulation of p53 and which is independent of CD95-CD95L interactions.
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PMID:Apoptosis of haematopoietic cells upon thymidylate synthase inhibition is independent of p53 accumulation and CD95-CD95 ligand interaction. 1111 3

We present a new approach towards the detection of the mRNAs in formalin-fixed, paraffin-embedded samples using a reverse transcriptase (RT)-polymerase chain reaction (PCR). The total RNAs were extracted from 10-micron-thick sections and were reverse-transcribed, then the RT-products were subjected to PCR amplification of GAPDH mRNA for screening the mRNA degradation. Next, nested PCR was performed for examining the expression of p53-related genes, p21WAF1, MDM2, p33ING1 and p14ARF. GAPDH mRNA expression was detectable in 12 out of 21 oral squamous cell carcinoma (SCC) samples. p21WAF1 mRNA expression was detectable in 5 out of 12 SCC samples, MDM2 mRNA expression was detectable in 5 our of 12 SCC samples and p33ING1 mRNA expression was detectable in 6 out of 12 SCC samples. However, the expression of p14ARF mRNA was not detectable in any of the samples. Seven out of 12 oral SCC samples showed abnormal nuclear accumulation of p53 protein by immunohistochemical staining, whereas 5 out of 12 oral SCCs showed negative staining for p53 protein. Of of p33ING1 mRNA. One of these was a verrucous carcinoma in which the p53 gene products might be inactivated by the oncoprotein E6 of human papilloma virus. Thus, the p53 tumor suppressor pathway was disrupted in most oral SCCs at the cellular levels, due to either an abnormality in p53 itself or loss of expression of p53 regulatory factors. This method would assist in making diagnosis, determining therapeutic strategy and predicting the prognosis of various cancers including oral SCCs.
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PMID:RT-PCR amplification of RNA extracted from formalin-fixed, paraffin-embedded oral cancer sections: analysis of p53 pathway. 1292 30

Chondrocytes from human adult articular healthy cartilage were transfected in primary culture with a plasmid containing two human papilloma virus type 16 early function genes: E6 and E7, using the highly efficient cationic liposome-mediated (lipofection) procedure. The transfection was verified by reverse transcriptase-polymerase chain reaction analysis of E7 mRNA and by immunofluorescence localization of the E7 protein in the cell cytoplasm. The established chondrocyte cell line was examined in monolayer and in two culture conditions that were described to re-induce differentiated characteristics: culturing in a serum-free defined medium and seeding on a hyaluronan-based three-dimensional biomaterial. Immortalized cells were able to re-express the main markers of chondrocyte phenotype, both at mRNA and protein levels, under the two defined cultured conditions used. The cell line that we obtained may be a useful tool for increasing our knowledge of the genetic and biochemical events involved in the processes of cartilage growth and differentiation, and of the etiopathogenesis of many rheumatic diseases.
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PMID:Establishment of a new human immortalized chondrocyte cell line. 1525 51

Telomerase activity and human telomerase reverse transcriptase (hTERT) mRNA expression were investigated in cervical specimens and were correlated with cytologic findings and the presence of human papilloma virus (HPV) infection. Telomerase activity was evaluated by the telomeric repeat protocol assay and hTERT mRNA expression was evaluated by reverse transcriptase polymerase chain reaction (PCR). HPV DNA was detected by PCR, as well as restriction endonuclease digestion. HPV DNA was detected in all 82 specimens with abnormal cytologic findings and in 4 of 34 normal samples. Low-grade squamous intraepithelial lesions (LGSILs) were present in 74 of 82 specimens (90.2%) and high-grade squamous intraepithelial lesions (HGSILs) were present in 8 of 82 (9.75%) specimens. Seven of the eight HGSIL (87.5%) and 26 of 74 LGSIL (35.1%) specimens were hTERT positive, whereas all normal specimens were hTERT mRNA negative. Telomerase activity was detected in 21 of 74 (28.4%) LGSIL/atypical squamous epithelial cells of undetermined significance (ASCUS) and in five of eight (62.5%) HGSIL samples. A correlation was observed among telomerase activity, hTERT mRNA expression, and high-risk HPV infection in HGSIL samples (P < 0.001). High-risk HPV infection assessment showed 75% sensitivity and 72.2% specificity for HGSILs. Telomerase activity assessment in cervical smears showed sensitivity and negative predictive value (NPV) for HGSILs 62.5% and 96.7%, whereas specificity and positive predictive value (PPV) were 80.5% and 19.2%, respectively. hTERT mRNA expression assessment showed 87.5% sensitivity and 98.7% NPV for HGSILs, whereas specificity and PPV were 76% and 21.2%, respectively. Based on the above-described telomerase assessment values, it is suggested that the telomerase system might not be an appropriate diagnostic marker for cytology, given that the final evaluation must rely on a combination of all available test assessment data, clinical diagnosis, as well as the follow-up of all LGSIL samples that were positive for telomerase activation.
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PMID:The role of human telomerase catalytic subunit mRNA expression in cervical dysplasias. 1579 48

Squamous cell carcinomas of the oropharynx (SCCO) are often infected with oncogenic human papilloma virus (HPV) subtype 16. To determine the frequency of T cells specific for human leukocyte antigen (HLA)-A2.1 restricted HPV16 E7 protein-derived epitopes, tetramer analysis was performed using peripheral blood lymphocytes of 20 HLA-A2.1+ patients and 20 HLA-A2.1+ healthy individuals. Tetramers specific for 3 HPV16 peptides (E711-20, E782-90 and E786-93), an influenza matrix peptide (a model recall antigen) or an HIV reverse transcriptase peptide (a model novel antigen) were used in multicolor flow analysis. The HPV-specific T-cell frequencies were correlated with the HPV16 E7 and p16 status in tumor sections. In vitro stimulation (IVS) with autologous dendritic cells (DC) pulsed with HPV16 E7 epitopes was performed to demonstrate proliferation and antitumor activity of the HPV-responsive T cells. Frequencies of CD8+ T cells specific for HPV16 E7 peptides were not significantly different in patients with SCCO relative to normal donors. However, patients with tumors expressing HPV16 E7 (60%) and p16 (50%) had an increased frequency (p<0.05) of T cells specific for the E711-20 epitope compared to those with tumors negative for both markers. HPV16 E711-20 and HPV16 E786-93 specific T cells were expandable upon IVS with cognate peptide-pulsed DC and were reactive against peptide-pulsed targets or, in case of the E711-20 epitope-specific T cells, against HPV16 E7 expressing CaSki cell line. Thus, in patients with HPV16+ SCCO, precursor T cells specific for E711-20 epitope are present (1/3,947) in the circulation, are responsive to stimulation with the cognate viral peptide and recognize in vitro HPV16 E7+ tumor cells. Further studies have to elucidate why those T cells are unable to eliminate the tumor in vivo and this might also allow for finding potential strategies that will increase the chances of developing a future HPV-based vaccine in patients with SCCO.
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PMID:T cells specific for HPV16 E7 epitopes in patients with squamous cell carcinoma of the oropharynx. 1628 59

The immunohistochemical expression pattern of p16 in biopsy samples has been useful as part of a panel to distinguish adenocarcinomas arising from the endometrium from those arising from the endocervix. However, no information is available on the expression of p16 in uterine serous carcinoma (USC) or ovarian high-grade serous carcinoma that could be used for diagnostic purposes. Here, we retrospectively analyzed the immunohistochemical expression of p16 in 11 cases of USC (5 pure and 6 mixed with endometrioid adenocarcinoma) and 10 cases of ovarian high-grade serous carcinoma and compared p16 expression with that of p53 in the same samples. p16 was strongly expressed by 100% of tumor cells in all 11 uterine specimens and in 5 of the 10 ovarian specimens; of the other 5 ovarian specimens, 4 showed strong positivity in 20% to 80% of tumor cells, and 1 case showed only weak expression. Positivity for p53 was strong and diffuse (100% of tumor cells) in 5 uterine tumors and in 3 ovarian tumors. p53 expression in 6 of the uterine specimens and 7 of the ovarian specimens was present in fewer tumor cells, of weak intensity, or both. We also performed human papilloma virus (HPV) DNA in situ hybridization in 4 uterine pure serous carcinomas; all 4 were negative. The negative results were confirmed by reverse transcriptase in situ polymerase chain reaction. We conclude that p16, owing to its diffuse expression in USC, should not be interpreted as indicating cervical origin or HPV-induced carcinogenesis; however, p16 may be a better marker (albeit unspecific) than p53 for identifying USC. The overexpression of p16 in USC is unrelated to HPV. Further studies are necessary to determine whether p16 expression is useful in the differential diagnosis of ovarian high-grade serous carcinoma.
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PMID:Immunohistochemical overexpression of p16 and p53 in uterine serous carcinoma and ovarian high-grade serous carcinoma. 1758 20

We infected HeLa cells with low (10(-9) units), medium (10(-6) units), and high (10(-2) units) influenza B titers and compared the resulting human papilloma virus (HPV), retinoic acid receptor alpha subunit (RARalpha) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA content of surviving infected hosts with that of their uninfected precursors by semi-quantitative reverse transcriptase/polymerase chain reaction amplification (RT/PCR). This comparison revealed a moderate and drastic dependence of HPV and RARalpha mRNA content, respectively, but a complete independence of GAPDH mRNA expression on viral titer. A mechanism of adoptive replacement of tolerable cellular with viral gene expression was proposed to explain these findings. We conclude that the reported ability of influenza B viruses to specifically target and eliminate the cervical adenocarcinoma HeLa cell line studied may find practical applications in biological cancer management.
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PMID:On the mechanism of phenotypic conversion of human cervical adenocarcinoma HeLa cells surviving infection by influenza B virus: potential implications for biological management of adenocarcinomas. 1829 99


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