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)

This study was designed to investigate if neutralizing antibodies against HPV-11 are detectable in the serum of patients with condyloma acuminata (CA) or cervical intraepithelial neoplasia (CIN) using an in vitro infectivity assay for HPV-11. Purified HPV-11 virions were extracted from xenografted condyloma tissues implanted into athymic mice and used to infect cultured neonatal human foreskin keratinocytes (HFK) and an immortalized adult skin cell line (HaCaT). The presence of HPV-11-specific E1--E4 mRNA as detected by reverse transcriptase-polymerase chain reaction was indicative of early infection. Sera previously characterized for reactivity to HPV-11 and HPV-11 VLP (virus-like particles) by ELISA were tested for the ability to prevent HPV-11 in vitro infectivity. Neutralizing antibodies against HPV-11 were demonstrated when monoclonal antibodies or patient serum preincubated with HPV-11 virions prevented the infection of either of the two cell cultures, as shown by the absence of the E1--E4 mRNA transcript. Eleven (of 20) patients with CA were strongly ELISA reactive against HPV-11 virus-like particles. Five of these 11 patients also had detectable levels of neutralizing antibodies in their serum. It was also demonstrated that the neutralizing properties of the serum were titratable by endpoint dilution. None of 15 patients with CIN had detectable neutralizing antibodies against HPV-11. Neutralizing antibodies against HPV-11 can be detected in some patients with CA and the neutralizing effects of the patient sera can be titrated by endpoint dilution. The in vitro assay for the detection of neutralizing antibodies against HPV-11 may have utility for investigating the natural history of HPV infection and resolution, as well as assessing the efficacy of any putative HPV vaccine.
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PMID:Detection of serologic neutralizing antibodies against HPV-11 in patients with condyloma acuminata and cervical dysplasia using an in vitro assay. 926 79

Infections with high-risk human papillomaviruses (e.g., HPV-16) play an important role in the development of cervical intraepithelial neoplasia (CIN) and invasive cervical cancer (IC). Continued expression of the viral E6 and E7 genes is believed to be a key factor for oncogenic transformation of infected cells. Two spliced transcripts of the E6/E7 oncogenes, termed E6*I and E6*II, can be detected by reverse transcriptase polymerase chain reaction (RT-PCR). To increase the sensitivity of detecting E6/E7 transcripts in cervical scrapes we took advantage of a nested RT-PCR (nRT-PCR) protocol. In a series of 30 HPV-16-positive patients with histologic diagnoses ranging from nondysplastic epithelium to IC, the application of nRT-PCR significantly improved the detection of E6/E7 transcripts compared to conventional RT-PCR. The prevalence of E6/E7 spliced transcripts correlated with lesion severity and the nRT-PCR protocol allowed detection of these transcripts even in nondysplastic epithelium and CIN I lesions. Therefore, in epidemiologic follow-up studies, detection of E6/E7 transcripts by nRT-PCR should prove to be a useful diagnostic tool for risk evaluations regarding the development of CIN and its progression to cervical cancer, especially in high-risk HPV-type-infected patients with CIN 0 and CIN I.
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PMID:Detection of human papillomavirus type 16 E6/E7 oncogene transcripts in dysplastic and nondysplastic cervical scrapes by nested RT-PCR. 960 Aug 17

In this study, we investigated telomerase activity and human telomerase reverse transcriptase (hTERT) mRNA expression in relation to high-risk human papillomavirus (HPV) DNA presence in the spectrum of cervical premalignant lesions. Reconstruction experiments revealed that telomerase activity determined by the telomeric repeat amplification protocol assay and hTERT mRNA by reverse transcriptase-PCR could be detected in down to 100 and 1 SiHa cervical cancer cells, respectively. Telomeric repeat amplification protocol analysis on cervical tissue specimens revealed that none of the histomorphologically normal cervical samples (n = 8) and cervical intraepithelial neoplasia (CIN) grade I (n = 10) and grade II (n = 8) lesions had detectable telomerase activity. However, telomerase activity was shown in 40% of CIN grade III lesions (n = 15) and 96% of squamous cell carcinomas (n = 24). Despite the fact that hTERT mRNA was found at much higher frequencies, semiquantitative reverse transcriptase-PCR revealed that elevated hTERT mRNA levels were strongly correlated with detectable telomerase activity. Furthermore, telomerase activity and elevated hTERT mRNA levels were only detected in cases that contained high-risk HPV DNA. In contrast, low or undetectable hTERT mRNA levels were demonstrated in both high-risk HPV positive and negative cases. These data indicate that telomerase activity detectable with the assay used and concomitant elevated levels of hTERT mRNA reflect a rather late step in the CIN to squamous cell carcinoma sequence, which follows infection with high-risk HPV.
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PMID:Telomerase activity exclusively in cervical carcinomas and a subset of cervical intraepithelial neoplasia grade III lesions: strong association with elevated messenger RNA levels of its catalytic subunit and high-risk human papillomavirus DNA. 973 89

Genetic mutation of p53, which monitors DNA damage and operates cellular checkpoints, is a major factor in the development of human malignancies. A novel gene p63/p73L/p51, encoding a protein with significant homology to p53 and p73, was recently identified at 3q27-9. To investigate the penetration of p63 in cervical carcinogenesis, mutation and transcription analyses of p63 were performed in cervical carcinoma. A certain isotype of p63 called TAp63gamma encodes the acidic N-terminus and possesses a short C-terminus. Using reverse transcriptase-polymerase chain reaction-single strand conformation polymorphism (RT-PCR-SSCP) analysis for TAp63gamma, one mutation was found in the cervical carcinoma cell line SKG-I. However, no mutations causing amino acid substitutions or frameshifts were found in 54 cases examined for TAp63gamma, which is thought to be a tumor suppressor gene. While cervical carcinomas tended to yield a positive signal in the RT-PCR reaction designed to amplify transcripts encoding the acidic N-terminus, normal cervix and cervical intraepithelial neoplasia (CIN) did not express this transcript. These data suggest that the p63 gene does not play an essential role as a tumor suppressor gene, but expression of TAp63gamma may be speculatively associated with tumor growth in cervical carcinogenesis.
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PMID:Mutation and transcription analyses of the p63 gene in cervical carcinoma. 1056 21

To identify cellular genes that may be involved in human papillomavirus (HPV)-mediated immortalization mRNA differential display analysis was performed on preimmortal and subsequent immortal stages of four human keratinocyte cell lines transformed by HPV type 16 or 18 DNA. This yielded a cDNA fragment encoding the transcription factor GATA-3 that was strongly reduced in intensity in all immortal stages of the four cell lines. A marked reduction in both GATA-3 mRNA and protein expression in HPV-immortalized cell lines was confirmed by reverse transcriptase-polymerase chain reaction, Western blot analysis, and immunohistochemistry and was also shown to be apparent in cervical carcinoma cell lines. Immunohistochemical analysis of cervical tissue specimens showed a clear nuclear staining for GATA-3 in normal cervical squamous epithelium (n = 14) and all cervical intraepithelial neoplasia (CIN) I (n = 6) and CIN II lesions (n = 2). In contrast, 11% (1 of 9) of CIN III lesions and 67% (8 of 12) of cervical squamous cell carcinomas revealed a complete absence of GATA-3 immunostaining. Hence, complete down-regulation of GATA-3 expression represents a rather late event during cervical carcinogenesis. Whether GATA-3 down-regulation is etiologically involved in HPV-mediated immortalization and cervical carcinogenesis remains to be examined.
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PMID:Down-regulation of GATA-3 expression during human papillomavirus-mediated immortalization and cervical carcinogenesis. 1205 98

Translation initiation factor eIF-4E (eukaryotic initiation factor 4E) is a 25 kd messenger RNA cap-binding phosphoprotein and is involved in the initiation of protein synthesis. The expression is known to be elevated in several carcinomas as compared with normal tissues and benign lesions. In the present study, we undertook to determine whether eIF-4E expression is associated with progression in cervical neoplasia. eIF-4E expression was evaluated by immunohistochemistry in 88 formalin-fixed, paraffin-embedded cervical tissues; 10 normal cervical specimens; 19 low-grade cervical intraepithelial neoplasias (CINs); 19 high-grade CINs; and 40 invasive squamous cell carcinomas (ISCCs). In addition, eIF-4E expression was evaluated at the RNA level in fresh frozen cervical carcinoma tissues by real-time quantitative reverse transcriptase polymerase chain reaction. Immunohistochemical staining showed that eIF-4E expression was undetectable in most normal cervical squamous epithelial tissues (90%), but variable staining was observed in the basal layer of all normal endocervical glands. eIF-4E expression, which was mainly observed as cytoplasmic staining, gradually increased in accordance with histopathologic grade in the order low-grade CIN < high-grade CIN < ISCC (P < .001) and, in particular, was strongly detected in all ISCC cases. Furthermore, real-time quantitative reverse transcriptase polymerase chain reaction revealed that eIF-4E expression in tumor was significantly enhanced versus normal cervical tissues (P = .037). These results suggest that eIF-4E may play a significant role in tumor progression of cervical neoplasia and may represent useful markers for malignant transformation of cervical squamous cells.
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PMID:eIF-4E expression is associated with histopathologic grades in cervical neoplasia. 1626 Feb 73

Human papillomaviruses (HPVs) are etiologic for the development of cervical cancer and its precursor lesions, cervical intraepithelial neoplasia (CIN). Nearly all cervical carcinomas (CaCx) harbor HPV DNA, but the presence of HPV alone is not indicative of the future development of neoplasia. While both normal and abnormal smears may harbor HPV DNA, the detection of HPV mRNA is associated, although not exclusively, with abnormal cytology. Recent observations suggest women with a high HPV viral load are at a significantly greater risk for CIN development--particularly those infected with high-risk (HR) HPV types, such as HPV type 16 (HPV 16). Thus, assays capable of detecting HPV transcripts may have useful prognostic value and could be utilized to identify biological markers for progression to high-grade cervical disease. This chapter describes the nested reverse transcriptase (nRT)-polymerase chain reaction (PCR) methods developed in our laboratory for the detection of the majority of all early region HPV-16 transcripts.
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PMID:Detection of HPV transcripts by nested RT-PCR. 1635 Apr 9

The human papillomavirus (HPV) plays an important role in the progression of cervical carcinoma. High-risk (HR) HPV types have been mainly identified in cytologic high-grade squamous intraepithelial lesions (HSILs) and histologic invasive carcinoma of the cervix. We examined cervical swabs of patients with abnormal Papanicolaou (Pap) smears, diagnosed as low-grade squamous intraepithelial lesions (LSILs) including atypical squamous cells of uncertain significance or HSILs. Low-risk (LR) HPV and HR-HPV types were identified by the Digene Hybrid Capture II test. Two-dimensional (2D) gel electrophoresis was used to specify the physical state of HPV DNA sequences. Expression of E6/E7 messenger RNA (mRNA) transcripts was analyzed by reverse transcriptase-polymerase chain reaction. Histopathologic results were correlated to the patients' physical status and HPV DNA mRNA transcripts. Pap smears with HPV infections of LR and HR types were correlated to the degree of squamous intraepithelial lesions (SILs). Comparing the physical states of HPV DNA sequences with the expression of HPV E6/E7 mRNA transcripts, all types were identified only as extrachromosomal in benign cervical smears, cervical intraepithelial neoplasia (CIN) I and II. HPV16 showed all physical states in CIN III/carcinoma in situ (CIS), whereas HPV18 only existed in mixed and integrated forms. HPV31/33/52b/58 appeared in all stages of lesions most commonly in extrachromosomal form; in integrated form, they were present only in CIN III/CIS. Although integration of some HR-HPV types is not always necessary for progression of SILs, the above-mentioned method is useful to analyze the physical state of HPV DNA sequences and predict the progression of SILs.
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PMID:Human papillomavirus DNA integration and messenger RNA transcription in cervical low- and high-risk squamous intraepithelial lesions in Austrian women. 1758 15

Virus integration into the host genome is a characteristic step during cervical carcinogenesis. Experimental data provide evidence that integration could result in increased levels of oncogene (E6/E7) transcripts. This is the first study in which the level of viral transcripts is correlated to the physical state of the viral genome in cervical intraepithelial neoplasia (CIN) and cervical carcinomas (CxCa). Using the APOT-assay integrate-derived transcripts only were detected in 3/28 (11%) CIN and in 28/55 (51%) carcinomas, respectively. The remaining biopsies contained either episome-derived transcripts only or both mRNA species. SybrGreen real time reverse transcriptase-PCR assays were used to quantify viral gene expression for (i) all transcripts initiated from p97, (ii) full-length E6, (iii) E6*I and (iv) E5 transcripts. E6/E7 transcript levels showed a broad distribution but similar median values irrespective of histopathological grading and physical state of the viral genome. Biopsies with integrate-derived transcripts only generally lacked E5-specific mRNA. Our data do not support the hypothesis that HPV integration invariably results in high levels of oncogene transcripts. Instead, constitutive expression of oncogene transcripts rather than the level of expression appears to be decisive for transformation and the maintenance of the malignant phenotype.
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PMID:Integration of the HPV16 genome does not invariably result in high levels of viral oncogene transcripts. 1782 99

This study was designed to investigate whether there is a correlation between the down-regulation of microRNA-218 (miR-218) and the presence of human papillomavirus (HPV) infection in the pathogenesis of cervical cancer. The participants comprised 78 women with cervical intraepithelial neoplasia (CIN); 22 (28.2%) had CIN 1, 27 (34.6%) had CIN 2 and 29 (37.2%) had CIN 3. MiR-218 expression was determined by reverse transcriptase polymerase chain reaction and HPV genotypes in tissue specimens were identified with a microarray test kit. The findings showed that miR-218 levels in patients with high-risk HPV infection were lower than in those infected with low-risk or intermediate-risk HPV, or in those who were HPV-free. MiR-218 levels in patients with high-risk CIN were lower than in those with low-risk CIN. We concluded that infection with high-risk HPV lowered the expression of miR-218 and that down-regulation of miR-218 was involved in the pathogenesis of cervical cancer.
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PMID:High-risk human papillomavirus reduces the expression of microRNA-218 in women with cervical intraepithelial neoplasia. 2130 87


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