| possible transplacental transmission of human papillomaviruses. | the objective of this study was to examine the possibility of intrauterine human papillomavirus infection of fetuses by transplacental transmission of human papillomavirus before delivery. | 1992 | 1310201 |
| 'hit and run' oncogenesis by human papillomavirus type 18 dna. | transfection of an immortalized cell line (ae), derived from syrian hamster embryo cells, with human papillomavirus type 18 (hpv 18) dna induced morphological transformation and these transformed cells were tumorigenic in nude mice. southern blot analysis revealed that the transfected viral dna was retained in all the cell lines tested, however, all these transformed cells contained only less than one copy per cell of viral genome. eleven cloned cell lines were established from a tumor cell line ... | 1992 | 1317646 |
| functional analysis of e2-mediated repression of the hpv18 p105 promoter. | transcription of the transforming genes e6 and e7 of the human papillomavirus type 18 (hpv18) can be repressed by the product of the e2 open reading frame. mutations were introduced in the cis-responsive elements upstream from the e6 and e7 transcriptional promoter, p105. the effect of these mutations in the absence or presence of e2 was examined in the human cervical carcinoma cell line c33, transfected with expression plasmids. in the presence of hpv18 e2, repression was relieved only when bot ... | 1991 | 1645591 |
| increased intracellular calcium is associated with progression of hpv-18 immortalized human keratinocytes to tumorigenicity. | studies were conducted using normal and human papillomavirus type 18 (hpv-18) immortalized human keratinocytes to assess possible alterations in the differentiation process as a consequence of increased intracellular calcium concentration. normal keratinocytes exposed to increased extracellular calcium or the phorbol ester tpa, exhibited terminal differentiation characteristics. however, late passage hpv-18 immortalized keratinocytes (designated fep-1811) were resistant to such terminal differen ... | 1991 | 1654210 |
| presence of human papillomavirus type 18 dna in a pharyngeal and a laryngeal carcinoma. | we examined the presence of human papillomavirus (hpv) genome in pharyngeal and laryngeal squamous cell carcinomas by employing the polymerase chain reaction. we detected hpv 16 dna in one of 11 pharyngeal carcinomas and in 3 of 28 laryngeal carcinomas, and hpv 18 dna in a pharyngeal and a laryngeal carcinoma. in one of the laryngeal carcinomas, dna of both hpv types 16 and 18 were detected. to our knowledge, this is the first report of detection of hpv type 18 in head and neck carcinomas. | 1991 | 1661280 |
| human papillomavirus type 18 in conjunctival intraepithelial neoplasia. | human papillomaviruses are oncogenic viruses that have been found in a variety of epithelial neoplasias. we sought to confirm their presence in conjunctival intraepithelial neoplasia. five tumors were studied with a polymerase chain-reaction assay designed to detect the e6 region of human papillomavirus types 16 and 18. human papillomavirus type-16 dna was found in four of the five tumors, including two tumors that contained both type-16 and type-18 dna. viral dna was not present in the fifth tu ... | 1990 | 2164326 |
| a member of the activator protein 1 family found in keratinocytes but not in fibroblasts required for transcription from a human papillomavirus type 18 promoter. | papillomaviruses are tissue specific and replicate in differentiating keratinocytes. we are interested in the question of tissue specificity at the level of transcription. we used extracts from human keratinocytes and human fibroblasts at low passage number and from hela cells to look for factors binding to the e6 promoter of human papillomavirus type 18 (hpv-18) dna by footprint and gel mobility shift experiments. we found a factor present in hela and keratinocyte extracts but not in fibroblast ... | 1990 | 2168967 |
| small-cell neuroendocrine carcinoma of the cervix. a human papillomavirus type 18-associated cancer. | small-cell undifferentiated carcinomas comprise a rare but aggressive subset of uterine cervical neoplasms. analogous to small-cell anaplastic carcinoma of the lung, these tumors frequently exhibit neuroendocrine differentiation. although human papillomaviruses (hpv) types 16 and 18 are strongly associated with the development of cervical squamous carcinoma, there is as yet little information describing the relationship of these viruses to small-cell carcinomas. to address this question, we anal ... | 1991 | 1845923 |
| transformation of rat-embryo immortalized fibroblasts by the e6-e7 region of human papillomavirus type 18. | plasmids containing the e6 and e7 open reading frames of human papillomavirus type 18 transformed rat-embryo fibroblasts when expressed under the cytomegalovirus promoter. the fibroblasts had been previously immortalized with the large t-antigen gene of the polyomavirus to produce rat embryo fibroblast (large t-antigen) [ref(lt)] cells. ref(lt) cells were transformed by the e6 and e7 sequences to anchorage independence and tumourigenicity, but there were no significant morphological alterations. ... | 1991 | 1661187 |
| repression of the human papillomavirus type 18 enhancer by the cellular transcription factor oct-1. | the role of cellular factors involved in the transcriptional regulation of the cancer-associated human papillomavirus type 18 (hpv18) is yet poorly understood. the presence of an oct-1-binding site within the hpv18 upstream regulatory region led us to investigate the influence of oct-1 on viral transcription. cotransfection of oct-1 expression plasmids together with luciferase reporter constructs containing hpv18 regulatory sequences indicated that oct-1 can transcriptionally repress the hpv18 u ... | 1991 | 1654457 |
| human papillomavirus type 18 e6*, e6, and e7 protein synthesis in cell-free translation systems and comparison of e6 and e7 in vitro translation products to proteins immunoprecipitated from human epithelial cells. | expression of the e6 and e7 transforming genes of human papillomavirus type 18 (hpv18) occurs via structurally bicistronic mrnas in which the downstream open reading frame (orf) e7 is preceded either by the full-length orf e6 or by a spliced orf, e6*. we have used in vitro transcription and translation of hpv18 cdnas in order to analyze the synthesis of e6*, e6, and e7 proteins and to compare the e6 and e7 in vitro translation products with the authentic proteins immunoprecipitated from cervical ... | 1991 | 1651423 |
| delineation of human papillomavirus type 18 enhancer binding proteins: the intracellular distribution of a novel octamer binding protein p92 is cell cycle regulated. | the enhancer of human papillomavirus type 18 consists of two functionally redundant domains, one is partially conserved between hpv18 and hpv16, both mediate strong transcriptional enhancement. in contrast, short fragments of the enhancer mediate low transcriptional enhancement, suggesting that there is functional cooperation between hpv enhancer binding factors. previously interactions of the enhancer with nf-1, ap1 and steroid receptors were shown by emsa. here we show by binding site blotting ... | 1991 | 1645869 |
| activation of human papillomavirus type 18 gene expression by herpes simplex virus type 1 viral transactivators and a phorbol ester. | several viral trans-activators and a tumor promoter were examined for the ability to activate human papillomavirus type 18 (hpv-18) gene expression. a plasmid containing the hpv-18 noncoding region placed upstream of the chloramphenicol acetyltransferase reporter gene was cotransfected with different herpes simplex virus type 1 (hsv-1) genes into several cell lines. both hsv-1 tif and icp0 activated hpv-18 expression; however, activation by tif was observed only in epithelial cells, while icp0 s ... | 1989 | 2536091 |
| activation of human papillomavirus type 18 e6-e7 oncogene expression by transcription factor sp1. | the human papillomavirus 18 (hpv18) e6 and e7 proteins are considered to be primarily responsive for the transforming activity of the virus. in order to analyse the molecular mechanisms resulting in viral oncoprotein expression, it is necessary to identify the factors involved in the transcriptional regulation of the e6/e7 genes. here we define by gel retardation experiments a sequence aberrant sp1 binding site present in the promoter proximal part of the viral transcriptional control region (up ... | 1992 | 1336181 |
| papillomavirus polypeptides e6 and e7 are zinc-binding proteins. | papillomavirus proteins e6 and e7 have cys-x-x-cys repeats which have been suggested to mediate zinc binding. we have developed a modification of an assay that detects zinc binding to proteins immobilized on filters. using well-characterized metalloproteins, we show that, under reducing conditions, this assay distinguishes proteins that coordinate zinc through cysteine residues from those that bind the metal through other amino acids. under these conditions, e6 and e7 polypeptides of human papil ... | 1989 | 2536841 |
| the e2 binding sites determine the efficiency of replication for the origin of human papillomavirus type 18. | human papillomaviruses (hpv-s) have been shown to possess transforming and immortalizing activity for many different, mainly keratinocyte cell lines and they have been detected in 90% of anogenital cancer tissues, which suggests a causative role in the induction of anogenital and other tumours. we have exploited a quantitative assay to identify and characterize the origin of replication of the human papillomavirus type 18 (hpv-18), one of the most prevalent types in the high-risk hpv group. repl ... | 1992 | 1334259 |
| presence of human papillomavirus type 18 dna in vulvar carcinomas and its integration into the cell genome. | we have screened 78 genital tract tumours from italian female patients for the presence of human papillomavirus type 16 (hpv-16) and hpv-18 dna. dot and southern blot hybridization experiments revealed that dna sequences of hpv-16 and/or hpv-18 are present in 66% of tumour samples. hpv-18 was detected in 80% of vulvar carcinomas. in these tumours the integration of hpv-18 dna seems to occur in the e1/e2 region of the virus genome with long deletions in almost all samples. the invariable retentio ... | 1989 | 2543791 |
| identification of a negative regulatory domain in the human papillomavirus type 18 promoter: interaction with the transcriptional repressor yy1. | the human papillomavirus type 18 (hpv-18) promoter contains a tpa responsive element (tre) which confers tpa responsiveness on a heterologous promoter. in the context of the hpv-18 promoter, however, this ap-1 site is inactive. we have identified a negative regulatory domain in the hpv-18 promoter which represses the constitutive and tpa-induced ap-1 activity. this negative regulatory sequence has been mapped to 44 nucleotides (ol13). we identified this element as a transcriptional silencer base ... | 1992 | 1330541 |
| molecular cloning, analysis, and chromosomal localization of a mouse genomic sequence related to the human papillomavirus type 18 e5 region. | the e5 open reading frame (orf) from bovine papillomavirus type 1 (bpv 1) as well as the e5 orfs from human papillomaviruses (hpv) type 6 and type 16 have been reported to transform immortalized rodent cells. in an analysis of murine and human tumors for the presence of putative papillomavirus-related sequences, we cloned amplified cellular sequences from the mouse cell line eb that cross-hybridized with the e5 orf of hpv 18. a 2.1-kb fragment termed hc1 was sequenced. in normal murine cells, it ... | 1992 | 1326990 |
| e6 protein of human papillomavirus type 18 binds zinc. | the e6 open reading frames of human and animal papillomaviruses encode a transforming protein containing a conserved pattern of repeating cysteine doublets (cys-x-x-cys) similar to that found in steroid receptor zinc finger proteins. the spacing between the cysteine doublets, however, is twice as long as in any other zinc finger protein. to demonstrate that an e6 protein could indeed bind zinc, we synthesized the human papillomavirus type 18 e6 protein in insect cells with a baculovirus vector a ... | 1989 | 2550872 |
| the e6-e7 region of human papillomavirus type 18 is sufficient for transformation of nih 3t3 and rat-1 cells. | plasmids containing the e6 and e7 open reading frames of human papillomavirus type 18 expressed from an autologous transcriptional control region were sufficient for transformation of nih 3t3 and rat-1 cells. transformation by these sequences did not always involve morphological alterations even though anchorage-independent growth occurred at a high frequency. in these cells, the efficiency of transformation by the e6 and e7 construct was equivalent to or, in most cases, better than that observe ... | 1987 | 2822969 |
| changing the spacing between metal-binding motifs decreases stability and transforming activity of the human papillomavirus type 18 e7 oncoprotein. | spacing composed of 29 amino acids (aas) between a pair of metal-binding motifs, cys-x-x-cys, is common to human papillomavirus (hpv) zinc-binding oncoproteins e6 and e7 from various hpv types. from the hpv 18 e7 gene encoding a 105-aa protein with the motifs at aas 65-68 and 98-101, we constructed expression plasmids for two mutants, 18del73 and 18ins84, with varied spacing between the motifs. mutant proteins 18del73 and 18ins84 had a deletion from aas 74 to 88 and an insertion of three aas sub ... | 1992 | 1325712 |
| effect on cancer cells of plasmids that express antisense rna of human papillomavirus type 18. | some human squamous cell carcinomas contain dna of human papillomaviruses (hpv) and express rna from the e6 and e7 genes. we have examined the effect of plasmids that express antisense rna of these genes on the growth of the human cancer cell lines hela, c4-1, and 1483, which contain hpv type 18 dna. as controls, the human cancer cell line 183 and the vero line of monkey kidney cells were used, which do not contain hpv. plasmids were introduced into the cells by electroporation; cells that conta ... | 1992 | 1324791 |
| retinoic acid-mediated repression of human papillomavirus 18 transcription and different ligand regulation of the retinoic acid receptor beta gene in non-tumorigenic and tumorigenic hela hybrid cells. | human papillomavirus type 18 (hpv18) belongs to the group of genital papillomaviruses involved in the development of cervical carcinomas. since retinoic acid (ra) is a key regulator of epithelial cell differentiation and a growth inhibitor in vitro of hpv18-positive hela cervical carcinoma cells, we have used hela and hela hybrid cells in order to analyse the effects of ra on expression of the hpv18 e6 and e7 oncogenes and of the cellular ra receptor genes rar-beta and -gamma. we show here that ... | 1992 | 1318198 |
| two ap1 sites binding junb are essential for human papillomavirus type 18 transcription in keratinocytes. | the activity and epithelial tropism of the human papillomavirus type 18 p105 early promoter, which directs the synthesis of the e6 and e7 transforming genes, are controlled by cis elements included in the viral long control region. to identify potential cellular regulators of this promoter, we mutagenized one or both of the 5'-tgactaa-3' cis elements capable of interacting with the ap1 transcription factor, which is composed either of homodimers or heterodimers of the jun products or of heterodi ... | 1992 | 1316480 |
| recombinant retroviruses encoding human papillomavirus type 18 e6 and e7 genes stimulate proliferation and delay differentiation of human keratinocytes early after infection. | human papillomavirus (hpv) dnas are detected in most genital dysplasias and cancers, suggesting that these viruses perturb epithelial growth and differentiation. the e6 and e7 genes of hpv type 18 induce immortality in keratinocytes cultured from genital tract epithelia, and the immortal cell lines display aberrant squamous differentiation. to examine whether the e6 and e7 proteins directly alter keratinocyte growth and differentiation, high-titer recombinant retroviruses were constructed for ef ... | 1992 | 1314365 |
| spontaneous production of growth factors for human lymphocytes from a human papillomavirus type 18-contained foreskin fibroblast cell line. | an immortalized fibroblast cell line, designated as ccfs-1/kmc, derived from human neonatal foreskin fibroblasts, contained human papillomavirus (hpv) type 18 dna. since this newly established cell line could spontaneously secrete activating factors for normal human blood lymphocytes, the synthesis and release of potent inflammatory cytokines from this cell line were checked. to determine the presence of cytokines in the supernatant collected from the cell line, tests by a cytokine-specific elis ... | 1992 | 1313887 |
| interplay of viral and cellular proteins along the long control region of human papillomavirus type 18. | the long control region of human genital papillomavirus type 18 harbors transcription regulatory elements, such as the e6 promoter and a cell type-specific enhancer independent of the e2 protein. by performing dnase i footprint experiments in vitro with protein extracts from different cell lines and tissues we searched for cellular factors interacting with the totality of the control region. we detected a total of eight different protected sites; most of them were found with all the extracts. tw ... | 1988 | 2845145 |
| langerhans' cells and subtypes of human papillomavirus in cervical intraepithelial neoplasia. | there is strong circumstantial evidence that human papillomavirus is a cofactor in the development of cervical neoplasia. systemic immunosuppression has also been implicated. a study was therefore carried out examining the relation between subtypes of human papillomavirus and local immunocompetent cells in the cervix. colposcopically directed punch biopsy specimens were taken from normal cervix and from histologically proved cervical intraepithelial neoplasia for immunohistochemical studies. hum ... | 1988 | 2846100 |
| combined herpes simplex virus type 2 and human papillomavirus type 16 or 18 deoxyribonucleic acid leads to oncogenic transformation. | tumorigenic transformation was produced by combining herpes simplex virus type 2 and human papillomavirus type 16 or 18 deoxyribonucleic acid (each is associated with cervical carcinoma). recombinant human papillomavirus type 16 and 18 deoxyribonucleic acid each containing a head-to-tail dimer of the full-length human papillomavirus respective genomes, induced morphologic transformation in an immortalized cell line (ae), obtained by transfection of syrian hamster embryo cells with immortalizing ... | 1988 | 2847531 |
| a t-helper cell epitope overlaps a major b-cell epitope in human papillomavirus type 18 e2 protein. | cultivated cd4+ t-helper cells from two patients with cervical adenocarcinoma showed responses to a peptide ektgiltvtyhsetqrtk derived from an e2 protein of human papillomavirus type 18 (hpv 18), but not to a corresponding hpv 16 peptide (hksaivtltydsewqrdq). serum antibodies in the hpv 18 peptide were also demonstrated in these patients. the gilt motif resembles a common pattern present in many t-cell epitopes, and is located at the beginning of an 11-amino acid-long a-helix structure close to ... | 1992 | 1282020 |
| detection of human papillomavirus deoxyribonucleic acid in exfoliated cervicovaginal cells as a predictor of cervical neoplasia in a high-risk population. | specific types of human papillomavirus are currently implicated as etiologic agents of precancerous and cancerous lesions of the cervix. we have previously described the use of cervicovaginal lavage and molecular hybridization to detect human papillomavirus infections of the cervix. we report here the predictive value of this method of human papillomavirus detection to identify women with biopsy proved dysplastic and cancerous lesions of the cervix. one hundred ninety-one women from a city hospi ... | 1988 | 2849881 |
| characterization of primary human keratinocytes transformed by human papillomavirus type 18. | primary human epithelial cells were cotransfected with phpv-18 and psv2neo, and cell strains were generated by selecting in g418. one cell strain (fe-a), which exhibits an extended life span, is currently in its 30th passage. in comparison, control cultures can only be maintained up to the seventh passage. southern blot analysis revealed the presence of at least one intact, integrated viral genome in these cells. fe-a cells showed altered growth properties, characterized by a change in morpholog ... | 1988 | 2452896 |
| rapid dysplastic transformation of human genital cells by human papillomavirus type 18. | this study delineates differences in biologic activity between human papillomavirus (hpv) types 16 and 18. human cervical and foreskin epithelial cells were cultured and transfected with recombinant hpv-16 and -18 dna, resulting in immortalized cell lines. normal epithelial cells as well as hpv-16 and -18 immortalized cells of both early passages (less than 40 population doublings) and late passages (greater than 180 population doublings) were transplanted in athymic mice. normal squamous cells ... | 1990 | 2172117 |
| suppression in vivo of human papillomavirus type 18 e6-e7 gene expression in nontumorigenic hela x fibroblast hybrid cells. | the e6 and e7 genes of the cancer-associated human papillomavirus (hpv) types 16 (hpv16) and 18 (hpv18) can induce cell immortalization in vitro in normal human keratinocytes. this, however, is not associated with tumorigenicity in vivo. on the other hand, tumorigenicity of hpv18-positive hela cervical carcinoma cells can be suppressed by fusion of hela cells with normal human keratinocytes or fibroblasts. we have addressed the question of whether suppression of tumorigenicity in hela x fibrobla ... | 1990 | 2168962 |
| human papillomavirus type 18 dna is integrated at a single chromosome site in cervical carcinoma cell line sw756. | sw756, a cervical carcinoma cell line, has multiple copies of human papillomavirus type 18 dna sequences. the integration site of human papillomavirus type 18 dna was localized by in situ hybridization to chromosome 12 at band q13. this single integration site corresponds to a heritable fragile site, which may have facilitated the integration of the viral dna. | 1987 | 3033295 |
| expression of the human papillomavirus type 18 e7 gene by a cassette-vector system for the transcription and translation of open reading frames in eukaryotic cells. | we have constructed and functionally tested a cassette-vector-system for the transcription and translation of open reading frames (orfs) in cells of higher eukaryotes. the vectors are derived from the plasmid pbr322 and can be selected and amplified in escherichia coli. alternative eukaryotic promoters can be inserted between the restriction sites sphi and kpni, translation initiation motifs between kpni and bglii, linkers for the adjustment of the translation reading frame and the insertion of ... | 1987 | 3034570 |
| immortalization and altered differentiation of human keratinocytes in vitro by the e6 and e7 open reading frames of human papillomavirus type 18. | the e6-e7 region of human papillomavirus types 16 and 18 is selectively retained and expressed in cervical carcinoma cells. in cultured human keratinocytes, expression of the e6 and e7 open reading frames of human papillomavirus type 18, under the control of its homologous promoter, resulted in high-frequency immortalization. furthermore, by using a system that allows for stratification of keratinocytes in vitro (raft system), we observed that the morphological differentiation of these e6-e7 imm ... | 1990 | 2153221 |
| a novel nuclear inhibitor i-92 regulates dna binding activity of octamer binding protein p92 during the cell cycle. | nuclear dna binding protein p92 is a sequence specific octamer binding protein with identical molecular weight as the ubiquitous octamer binding protein oct-1. it binds to octamer related sequences from the enhancer of human papillomavirus type 18. the activity and intracellular distribution of p92 is regulated by extracellular signals. in serum starved hela-fibroblast hybrid cells p92 is localized to the cytosol. serum stimulation leads to nuclear import of p92. in fractions of asynchronously g ... | 1991 | 1945850 |
| progression of human papillomavirus type 18-immortalized human keratinocytes to a malignant phenotype. | we have developed a model system for progression of human epithelial cells to malignancy, using a human papillomavirus type 18 (hpv-18)-immortalized human keratinocyte cell line. cells of cell line fep-1811 were nontumorigenic in athymic mice through at least 12 passages in culture, but after 32 passages were weakly tumorigenic, producing tumors that regressed. after 62 passages they produced invasive squamous cell carcinomas that grew progressively. the progression to malignancy was associated ... | 1991 | 1846447 |
| human papillomavirus deoxyribonucleic acid as a prognostic indicator in early-stage cervical cancer: a possible role for type 18. | our purpose was to determine the prognostic significance of human papillomavirus deoxyribonucleic acid in cervical cancers. | 1995 | 7503185 |
| selective suppression of human papillomavirus transcription in non-tumorigenic cells by 5-azacytidine. | the transcription of human papillomavirus type 18 (hpv 18) is selectively suppressed in non-tumorigenic hela x fibroblast or hela x keratinocyte cell hybrids by 5-azacytidine. in contrast, viral gene expression is not influenced by 5-azacytidine in both tumorigenic hybrid segregants and in the parental hela cells. the suppression mechanism seems to operate at the level of initiation of transcription since nuclear run-on experiments show the absence of elongated nascent viral rna, whereas the tra ... | 1988 | 2457495 |
| human papillomavirus type 18 e6 and e7 antibodies in human sera: increased anti-e7 prevalence in cervical cancer patients. | antibody-reactive regions on the human papillomavirus type 18 (hpv-18) e6 and e7 proteins were identified with rabbit polyclonal anti-fusion protein sera by screening of an fd phage expression library containing subgenomic hpv-18 dna fragments and by testing of overlapping decapeptides representing the e6 and e7 open reading frames. peptides comprising the delineated regions (designated e6/1 to e6/4 and e7/1) were synthesized and used in an enzyme-linked immunosorbent assay (elisa) to detect ant ... | 1991 | 1722219 |
| the human papillomavirus type 18 (hpv18) e2 gene product is a repressor of the hpv18 regulatory region in human keratinocytes. | the human papillomavirus type 18 (hpv18) long control region (lcr) harbors transcriptional promoter and enhancer elements. recombinant plasmids bearing all or part of the hpv18 lcr cloned in enhancer or promoter configuration upstream of the chloramphenicol acetyltransferase (cat) gene were transfected into human fibroblasts and keratinocytes. although the hpv18 enhancer can function in the absence of e2 gene products in both fibroblasts and keratinocytes, the promoter activity of the hpv18 lcr ... | 1989 | 2476572 |
| a keratinocyte-specific transcription factor, krf-1, interacts with ap-1 to activate expression of human papillomavirus type 18 in squamous epithelial cells. | human papillomavirus type 18 (hpv-18) infects genital squamous epithelium and is an etiological agent of cervical cancer. cell-type-specific expression of hpv-18 is directed by the region upstream of the viral early genes that contains a transcriptional enhancer whose function is dependent solely on cellular factors. this element directs expression to high levels in squamous epithelial cells but is only weakly active in other cell types. we demonstrate by gel mobility-shift, methylation interfer ... | 1991 | 1656460 |
| hpv-18 immortalization of human keratinocytes. | the oncogenic potential of human papillomavirus type 18 which is found in a significant number of cervical and penile cancer biopsies was tested in primary human keratinocytes derived from neonatal foreskin. viral dna and a gene for resistance to neomycin were introduced into these cells by calcium phosphate transfection. selection of cells in g418 led to the isolation of resistant colonies which were propagated in culture. four cell lines termed fe-a, feh 18l, fep18-5, and fep18-11 have been ma ... | 1989 | 2479170 |
| human papillomavirus type 18 dna in gestational trophoblastic tissues and choriocarcinomas. | the objectives of our study were to better understand carcinogenesis of gestational trophoblastic tumors and to investigate the possible presence of human papillomavirus types 16 and 18 dna sequences in these tumors. amplification-based dna methodology was used on 11 hydatidiform moles, 5 invasive moles, 8 choriocarcinomas and 9 normal early placental tissues. human papillomavirus type 16 dna was not found in any of these tissues. although human papillomavirus type 18 dna was also not found in t ... | 1995 | 7591258 |
| intracellular localization and dna-binding properties of human papillomavirus type 18 e6 protein expressed with a baculovirus vector. | the e6 protein of human papillomavirus type 18 (hpv-18) is a putative zinc-finger protein that is expressed in hpv-18-induced genital neoplasias. we have studied the biochemical properties of e6 protein synthesized in large amounts with a baculovirus expression vector. when e6 protein was synthesized in insect cells infected with an e6-expressing baculovirus, the protein was localized to both nuclear and membrane fractions, with half-lives of 4 and 2 h, respectively. changing the first five amin ... | 1989 | 2535738 |
| identification of human papillomavirus type 18 transforming genes in immortalized and primary cells. | the selective retention and expression of the e6-e7 region of human papillomavirus (hpv) types 16 and 18 in cervical carcinomas suggests that these viral sequences play a role in the development of genital neoplasia. each of three possible gene products, e6, e6*, and e7, from this region of hpv-18 were examined for transforming properties in several types of rodent cells. we have found that in immortalized fibroblasts, both e6 and e7 (but not e6*) are capable of inducing anchorage-independent gr ... | 1989 | 2536832 |
| tissue restricted expression and chromosomal localization of the yb-1 gene encoding a 42 kd nuclear ccaat binding protein. | yb-1 cdna clones were isolated by binding site screening of a hela expression library using a human papillomavirus type 18 enhancer oligonucleotide. yb-1 belongs to a family of transcription factors which bind to recognition sequences containing a core ccaat element. yb-1 bound to its single stranded recognition sequence on the sense strand but not to the anti-sense strand. a synthetic peptide antiserum derived from the predicted yb-1 amino acid sequence identified a 42 kd nuclear protein in imm ... | 1992 | 1542575 |
| human papillomavirus type 18 is associated with less apoptosis in fibroblast tumours than human papillomavirus type 16. | in human cervical neoplasia human papillomavirus (hpv) type 18 has a higher cancer/cervical intraepithelial neoplasia (cin) prevalence ratio than hpv 16. fibrosarcomas derived from rat fibroblasts transfected with hpv 16 or 18 genomes showed increased apoptosis compared with controls. however, hpv 18 was associated with significantly less apoptosis than hpv 16, affording one possible explanation for the more rapidly progressive cervical neoplasia associated with hpv 18. | 1995 | 7669576 |
| karyotypic analysis of two related cervical carcinoma cell lines that contain human papillomavirus type 18 dna and express divergent differentiation. | the cell lines c-4i and c-4ii were established in culture from a nonkeratinizing squamous carcinoma of the uterine cervix. both lines contain human papillomavirus (hpv) type 18 dna (brandt et al., cold spring harbor laboratories, 5:179, 1987) and both are hypodiploid with similar, but not identical, karyotypes. each line expresses multiple characteristics of ectocervical epithelial differentiation, but the characteristics differ between the lines. in the present study, g banding of the lines sho ... | 1989 | 2540900 |
| amplification of the integrated viral transforming genes of human papillomavirus 18 and its 5'-flanking cellular sequence located near the myc protooncogene in hela cells. | the human papillomavirus type 18 integrated in the hela cell genome is amplified on chromosome 8. e6, e7, and e1 open reading frames are amplified 5-fold, and the late viral dna region, the viral long control region, and cellular flanking sequences are amplified 15-fold. the common 5'-flanking cellular dna was localized by in situ hybridization of normal and hela cells only on chromosome 8 band q24. this flanking probe is included in the amplification unit of colo320 cells, but in the case of he ... | 1989 | 2545339 |
| chromatin structure and transcriptional regulation of human papillomavirus type 18 dna in hela cells. | mapping analysis of the nucleosomal organization of integrated human papillomavirus type 18 (hpv18) dna in hela cells reveals a very prominent nuclease-hypersensitive site within the viral noncoding regulatory region that harbors transcriptional control sequences and coincides with most of the 5' ends of the cytoplasmic early mrnas. moreover, it is shown that the conserved coamplified 5' cellular flank, common to all hpv18 copies in hela cells and located close to the virus-cell integration site ... | 1989 | 2548528 |
| [detection of human papillomavirus type 16, 18 and 33 dna in stage i (pt1n0m0) squamous cell carcinoma of the lung by polymerase chain reaction]. | human papillomavirus (hpv) has been considered one of the important factors of malignant change. to investigate the occurrence of hpv dna in primary squamous cell carcinoma of the lung, we tried to detect hpv dna by polymerase chain reaction (pcr). formalin-fixed paraffin-embedded tissue specimens from 8 cases of stage i (pt1n0m0) squamous cell carcinoma of the lung were examined for the presence of human papillomavirus dna (type 16, 18 and 33) by polymerase chain reaction. dna was extracted fro ... | 1995 | 7745856 |
| inducible and constitutive enhancer domains in the noncoding region of human papillomavirus type 18. | the noncoding region of human papillomavirus type 18 (hpv-18) is shown to contain at least three enhancer elements. two of these elements are responsive to papillomavirus-encoded trans-acting factors, and the third element functions as a constitutive enhancer, requiring only cellular factors for activity. the first enhancer (ie2) is located proximal to the e6 cap site and is responsive to papillomavirus e2 trans-activator. the second enhancer (ie6) is located approximately 500 base pairs upstrea ... | 1988 | 2828662 |
| transcription of human papillomavirus type-18 dna in human cervical carcinoma cell lines. | | 1987 | 2832273 |
| study of the e2 gene product of the cottontail rabbit papillomavirus reveals a common mechanism of transactivation among papillomaviruses. | the long control region (lcr) of the cottontail rabbit papillomavirus (crpv) harbors a transcriptional promoter which can be transactivated, as reflected by cat gene expression, by cotransfection with plasmids which express the intact e2 open reading frame of crpv, human papillomavirus type 18 (hpv18), and bovine papillomavirus type 1 (bpv1). the e2 protein of crpv can also transactivate the lcrs of bpv1, hpv1, and hpv18 inserted in front of the cat gene in enhancer or promoter configuration. co ... | 1988 | 2833608 |
| nucleotide sequences of cdnas for human papillomavirus type 18 transcripts in hela cells. | hela cells expressed 3.4- and 1.6-kilobase (kb) transcripts of the integrated human papillomavirus (hpv) type 18 genome. two types of cdna clones representing each size of hpv type 18 transcript were isolated. sequence analysis of these two types of cdna clones revealed that the 3.4-kb transcript contained e6, e7, the 5' portion of e1, and human sequence and that the 1.6-kb transcript contained spliced and frameshifted e6 (e6*), e7, and human sequence. there was a common human sequence containin ... | 1988 | 2833614 |
| different human cervical carcinoma cell lines show similar transcription patterns of human papillomavirus type 18 early genes. | transcription of human papillomavirus type 18 (hpv18) dna in the human cervical carcinoma cell lines hela, c4-1 and sw756 was studied by nucleotide sequence analysis of hpv18-positive cdna clones isolated from a hela, c4-1 and sw756 cdna library, respectively, and the cdna sequences were used to predict the potential encoded proteins. the cdna clones from all three cell lines were found to be derived from virus-cell fusion transcripts in which 3'-terminal host cell sequences (different for each ... | 1986 | 3023067 |
| identification of human papillomavirus type 18 e6 polypeptide in cells derived from human cervical carcinomas. | we recently reported the expression of human papillomavirus type 18 (hpv-18) e6 protein in bacteria and the production of anti-e6 polyclonal antibodies. this work has now been extended with the production of a panel of monoclonal antibodies against the hpv-18 e6 protein. these antibodies demonstrate that there is little antigenic conservation in the e6 protein between hpv-16 and hpv-18, with only one antibody recognizing a cross-reactive epitope. we have used both the monoclonal and the polyclon ... | 1987 | 3033140 |
| nucleotide sequence and comparative analysis of the human papillomavirus type 18 genome. phylogeny of papillomaviruses and repeated structure of the e6 and e7 gene products. | the complete nucleotide sequence and genomic organization of human papillomavirus type 18, associated with cervical cancer, has been established. a detailed comparative analysis was undertaken leading to the identification of a number of features specific for genital papillomaviruses and the construction of a phylogenetic tree. genital papillomaviruses differ from other human and animal papillomaviruses as they possess a longer e1 open reading frame (orf) and have a characteristic control region ... | 1987 | 3039146 |
| identification of the human papillomavirus type 18 e6 and e6 proteins in nuclear protein fractions from human cervical carcinoma cells grown in the nude mouse or in vitro. | we recently reported the transcription patterns of human papillomavirus (hpv) type 18 sequences in human cervical carcinoma cell lines. the open reading frames (orfs) e6* and e6 represent the 5'-terminal cistrons in hpv18 mrnas. orf e6* was assumed to be specific for hpv types associated with genital carcinomas. to identify the predicted gene product, orf e6* from a hela cdna clone was expressed as an ms2 fusion protein in escherichia coli. the c-terminal 23 amino acid residues were chemically s ... | 1988 | 3284640 |
| alterations in physical state and expression of human papillomavirus type 18 dna following crisis and establishment of immortalized ectocervical cells. | integration of episomal human papillomavirus (hpv) dna in infected cervical lesions during malignant progression is frequently observed, but the importance of integration is poorly understood. we have studied immortalization by hpv-18 of human cervical cells as an in vitro model system. here, the status and expression of hpv-18 dna in precrisis ectocervical keratinocytes was compared with that in the same cells after crisis and establishment of immortalization. southern blots revealed, and two-d ... | 1995 | 7483827 |
| integration site of human papillomavirus type-18 dna in chromosome band 8q22.1 of c4-i cervical carcinoma: dnase i hypersensitivity and methylation of cellular flanking sequences. | the c4-i cell line derived from a non-keratinizing squamous cell carcinoma of the uterine cervix contains integrated human papillomavirus-18 dna. fluorescence in situ hybridization of c4-i cells demonstrated a single viral integration site at 8q22.1 on a derivative chromosome originating from an 8q;12q translocation. 8q22 is a site of chromosome fragility and is also recombinogenic in several human malignancies. dnase i hypersensitivity of the integration site was studied with a cellular flankin ... | 1994 | 7507697 |
| human papillomavirus type 18 e6* mrna in primary tumors and pelvic lymph nodes of hungarian patients with squamous cervical cancer. | seven biopsy specimens from squamous-cell carcinomas of the uterine cervix were examined by rt-pcr for human-papilloma-virus(hpv)-specific transcripts. with our hpv18-transcription-specific primer pair (5' nts 127-149; 3' nts 587-607), all 7 were shown to contain one strong viral mrna signal from the early 6/early 7 open reading frames (e6/e7 orfs). sequence analysis of the cloned pcr product proved that the transcript was generated by splicing out an intron in e6 from nucleotides 233 to 416, th ... | 1994 | 7508888 |
| identification of seroreactive epitopes of human papillomavirus type 18 e7 protein by synthetic peptides. | nine everlapping peptides covering the entire sequence of early protein e7 of human papillomavirus type 18 (hpv-18) were synthesized and tested as antigens with pools of selected human sera in elisa. peptides denoted 18/e7-2, 18/e7-3, and 18/e7-5 (amino acid positions 11-33, 21-40, and 41-60, respectively) were reactive with pooled sera originating from hpv-18 dna-positive cervical cancer patients but not with sera from hpv-16 dna-positive cervical cancer patients or from condyloma acuminata pat ... | 1993 | 7514354 |
| t-helper epitopes of the e7 transforming protein of cervical cancer associated human papillomavirus type 18 (hpv18). | the presence of t-helper epitopes within the e7 transforming protein of human papillomavirus type 18 (hpv18) was sought using a series of overlapping synthetic 15-20 mer peptides spanning the entire 105 amino acid sequence of this protein. two h-2k restricted t-helper epitopes were defined, comprising 44vnhqhlparra55 and 81ddlrafqqlf90 as the minimal t proliferative epitopes. peptides containing these epitopes were able to provide cognate help to b epitopes from hpv18e7 protein for production of ... | 1995 | 7542826 |
| a transcribed human sequence related to the mouse hc1 and the human papillomavirus type 18 e5 genes is located at chromosome 7p13-14. | the papillomavirus e5 genes play an important role in the induction of proliferation of infected cells, and these hpv genomic regions are affected by the events leading to integration of genital hpvs. two hpv18 e5-related, transcribed mouse sequences, hc1 and q300, have recently been described. we searched for human equivalents to these sequences, and isolated a clone with a 9.6 kb insert (633b) from a laryngeal carcinoma dna library, that strongly cross-hybridised with both the hpv18 e5 and hc1 ... | 1995 | 7581372 |
| multiple octamer-binding proteins are targets for the cell cycle-regulated nuclear inhibitor i-92. | p92 is a novel sequence-specific octamer-binding factor interacting with the enhancer of human papillomavirus type 18. the nuclear inhibitor i-92 regulates the dna binding activity of p92 during the cell cycle such that p92 dna binding is restricted to s-phase. the sequence motif ++ 5'-aattgcttgcataa, consisting of two partially overlapping octamer-related sequences, represents a recognition site for p92. it was the aim of this study to characterize the complexity of proteins interacting with th ... | 1995 | 7598804 |
| mutational analysis of adeno-associated virus rep protein-mediated inhibition of heterologous and homologous promoters. | the four rep proteins encoded by adeno-associated virus type 2 (aav-2) inhibit transcription of their own promoters and of several heterologous promoters. to gain insight into the molecular mechanism of rep-mediated transcription repression, we studied the effects of the four rep proteins on the accumulation of mrna transcribed from the human papillomavirus type 18 upstream regulatory region hpv18 urr, the human immunodeficiency virus long terminal repeat, and the aav-2 p5 and p19 promoters by t ... | 1995 | 7636994 |
| conditional immortalization of primary cells by human papillomavirus type 18 e6 and ej-ras defines an e6 activity in g0/g1 phase which can be substituted for mutations in p53. | the human papillomavirus (hpv) type 18 e6 gene cooperates with activated ha-ras to immortalize primary mouse cells in culture. using a plasmid where hpv18 e6 expression is regulated by the glucocorticoid inducible mmtv ltr, we have generated immortalized cell lines in which the continued expression of e6 was necessary for maintenance of the transformed phenotype. in the absence of exogenously added hormone these cells were found to arrest in g0/g1. furthermore, we demonstrate that the effects of ... | 1995 | 7651728 |
| human papillomavirus type 18 and intraepithelial lesions of the cervix. | the conventional perception of hpv type 18 is that it is associated principally with invasive cancer of the cervix. however, in precursor lesions it is frequently identified in lesions of lower grade morphology, in contrast to the typical high grade lesions associated with hpv 16. to better characterize this uncommon relationship of low grade morphology and high risk virus, we studied four low grade and two high grade intraepithelial lesions of the cervix which were shown to contain hpv 18 by po ... | 1994 | 8291603 |
| sequence variation in the e7 gene of human papillomavirus type 18 in tumor and non-tumor patients and antibody response to a conserved seroreactive epitope. | we have determined nucleotide sequences of the e7 open reading frame (orf) of human papillomavirus type 18 (hpv-18) isolates obtained from 18 cervical carcinomas from tanzanian and german patients and 8 cervical scrapings from tanzanian non-tumor patients. the hpv-18 prototype sequence was detected in only 3 out of 26 isolates. silent mutations were found at nt positions 640 and 751, whereas the mutations observed at nt positions 770, 806, 864 and 865 all change the respectively encoded amino ac ... | 1993 | 7678831 |
| effects of human papillomavirus type 18-specific antisense oligonucleotides on the transformed phenotype of human carcinoma cell lines. | dna of human papillomavirus type 18 is present in several human cancer cell lines that were derived from oral or cervical tumors, and it is known that several features of the transformed phenotype can be inhibited by expression of antisense rna to human papillomavirus (hpv). the present study was performed to find out whether antisense oligonucleotides were also inhibitory. synthetic oligonucleotides were made that were complementary to regions of the start codons of the e6 and e7 genes of hpv-1 ... | 1993 | 7683572 |
| mucin synthesis in immortalized canine tracheal epithelial cells. | to study the regulation of mucin synthesis in canine tracheal epithelial cells, it is desirable to establish a cell line which synthesizes mucin continuously. we adopted the approach of immortalizing canine tracheal epithelial cells using a vector encoding the human papillomavirus (type 18) e6 and e7 genes. the e6 and e7 genes are essential and sufficient for the immortalization of human genital keratinocytes, as well as human tracheal epithelium. primary epithelial cells from dog trachea were t ... | 1994 | 7734845 |
| transcriptional repression in normal human keratinocytes by wild-type and mutant p53. | wild-type p53 is a nuclear phosphoprotein that inhibits cell proliferation and represses transcriptionally most tata box-containing promoters in transformed or tumor-derived cell lines. this study demonstrates that p53 alters transcription of the long control region (lcr) of human papillomavirus type 18 (hpv-18). wild-type and mutant p53 143val to ala repressed the hpv-18 lcr promoter in normal human keratinocytes, the natural host cell for hpv infections. repression by wild-type p53 was also ob ... | 1995 | 7750099 |
| transformation of rat 3y1 cells by human papillomavirus type-18 dna. | rat 3y1 cell cultures transfected with human papillomavirus type-18 (hpv 18) dna produced foci of morphologically transformed cells capable of anchorage-independent growth. analyses of the transformed cell clones obtained after transfection with ecori-cleaved linear hpv 18 dna showed that, although the viral dnas integrated in the cell dna had rearrangements (probably around the sites of integration), they appeared to retain the putative transcriptional control region and the downstream area con ... | 1988 | 2836322 |
| human papillomavirus type 18 associates with more advanced cervical neoplasia than human papillomavirus type 16. | a type-specific, sensitive, polymerase chain reaction-based assay for human papillomavirus (hpv) types 6b, 11, 16, 18, and 33 was applied to 47 cervical carcinomas, 60 cases of cervical intraepithelial neoplasia (cin), and 24 samples of histologically normal cervix. as expected, the combined incidence of the common high-risk genital hpvs (types 16 and 18) was high in carcinomas (79%) and cin 2/3 (60%), low in cin 1 (25%), and nonexistent in the normal controls. analysis of the data by viral type ... | 1993 | 8387954 |
| analysis of individual human papillomavirus types in cervical neoplasia: a possible role for type 18 in rapid progression. | histologic and molecular analyses of 214 cervical biopsy specimens were performed to test the hypothesis that certain individual human papillomavirus types that are usually grouped together are differentially distributed in various grades of cervical intraepithelial neoplasia and invasive squamous carcinoma. specifically, types 16 and 18, which are commonly grouped together, were analyzed separately and compared. biopsies obtained from three different geographic sites in the united states and br ... | 1988 | 2841858 |
| prevalence of human papillomavirus type 18 dna in adenocarcinoma and adenosquamous carcinoma of the uterine cervix occurring in japan. | to identify whether the incidence of human papillomavirus (hpv) type 18 dna in adenocarcinoma and adenosquamous carcinoma is attributable to the histological types or geographical differences, the presence of hpv-16 and hpv-18 dna in carcinoma of the uterine cervix from japan were studied by in situ hybridization using tritium labeled hpv dna probes. hpv-18 dna was detected in 5 of 11 cases (45%) of adenocarcinoma, one case of adenocarcinoma in situ and 2 of 3 cases of adenosquamous carcinoma. i ... | 1988 | 2848332 |
| the expression of human papillomavirus type 18 e6 protein in bacteria and the production of anti-e6 antibodies. | human papillomavirus type 18 (hpv-18) has recently been closely linked with human malignant cervical lesions. the early region of the genome of the related bovine papillomavirus (bpv) has been shown to be important for the production of the transformed phenotype. bpv e6 has been shown to be a transforming protein. we report the primary structure of the hpv-18 e6 open reading frame and its predicted amino acid sequence. both e6 protein and e6-beta-galactosidase fusion protein were synthesized in ... | 1986 | 3018129 |
| e6 and e7 expression from the hpv 18 lcr: development of genital hyperplasia and neoplasia in transgenic mice. | human papillomavirus type 18 infection is highly associated with malignant tumors of the genital tract. to investigate the tissue specificity of the hpv long control region (lcr) and the transforming ability of the e6-e7 oncoproteins, an hpv-18 transgene containing the viral lcr and e6 and e7 genes was introduced into mice. three founder males exhibited enlarged seminal vesicles and preputial glands by 50 weeks of age. a line of transgenic mice was established by in vitro fertilization, and subs ... | 1995 | 7845684 |
| evolution of human papillomavirus type 18: an ancient phylogenetic root in africa and intratype diversity reflect coevolution with human ethnic groups. | papillomaviruses are an ideal model system for the study of dna virus evolution. on several levels, phylogenetic trees of papillomaviruses reflect the relationship of their hosts. papillomaviruses isolated from remotely related vertebrates form major branches. one branch of human papillomaviruses (hpvs) includes an ape and two monkey papillomaviruses, possibly because the diversification of the viruses predated the separation of the infected-primate taxa. this hypothesis predicts that the root o ... | 1993 | 8411344 |
| the e2 transcriptional repressor can compensate for sp1 activation of the human papillomavirus type 18 early promoter. | the e6/e7 early promoter (p105) of genital human papillomavirus type 18 contains binding sites for the viral regulator e2, tandemly repeated and closely flanked by two crucial promoter elements; the tata box downstream and an sp1 binding site upstream. we showed that binding of purified e2 and sp1 proteins in vitro to their neighboring sites is mutually exclusive and that sp1 is displaced by e2. however, this displacement did not result in repression of p105 transcription. in contrast, binding o ... | 1994 | 7933089 |
| a switch region determines the cell type-specific positive or negative action of yy1 on the activity of the human papillomavirus type 18 promoter. | yy1 is a zinc finger transcription factor which acts as either a repressor or an activator dependent on the promoter context. yy1 is a potent activator of the genuine human papillomavirus type 18 (hpv-18) upstream regulatory region (urr) in hela cells, which are known for high-level expression of the hpv-18 early genes. the activating activity of yy1 is dependent on the presence of a newly identified switch region located upstream of the yy1 binding site. deletion of this region causes yy1 to ac ... | 1995 | 7983700 |
| uterine cervix adenocarcinoma with both human papillomavirus type 18 and tumor suppressor gene p53 mutation from a woman having an intact hymen. | human papillomavirus (hpv) type 18 dna was found in an aggressively invasive adenocarcinoma tumor from a woman who had an intact hymen and denied any prior sexual intercourse. the viral dna was detected within the tumor tissue by polymerase chain reaction (pcr) using consensus primers for the l1 region of oncogenic high-risk genital hpvs. in order to determine mutations within the tumor suppressor gene p53, the gene exons were amplified by pcr followed by single-stranded conformation polymorphis ... | 1995 | 8522268 |
| human papillomavirus (hpv) type 18 e7 protein is a short-lived steroid-inducible phosphoprotein in hpv-transformed cell lines. | we used a capture elisa to quantify the e7 protein of human papillomavirus type 18 (hpv-18). in hela cells, which express low levels of immunoreactive e7 protein (ie7), ie7 had a mean half-life of 13.5 min. in hpv-18 e7 recombinant baculovirus (e7rec bv)-infected sf21 cells, which express higher levels of e7, the half-life of ie7 was much longer (90 min and > 24 h, with two different e7rec bvs). for two transformed human cervical cell lines expressing hpv-18 e7, exposure of the cells to hydrocor ... | 1994 | 8021595 |
| isolation of flat revertants from human papillomavirus type 18 e6e7 transformed 3y1 cells by transfection with a rat embryo fibroblast cdna expression library. | a rat embryo fibroblast (ref) cdna expression library was transfected into 3y1 cells transformed by human papillomavirus type 18 e6 and e7 genes and 10 flat revertants were isolated. these revertants expressed the same levels of e6 and e7 mrna as the parent cells, but had greatly reduced ability to form colonies in soft agar. suppression of transformation was dominant in cell hybrids generated by fusing each revertant with the parental transformed cells. furthermore, loss of transfected cdna was ... | 1993 | 8033227 |
| differential regulation of the je gene encoding the monocyte chemoattractant protein (mcp-1) in cervical carcinoma cells and derived hybrids. | malignant human papillomavirus type 18 (hpv18)-positive cervical carcinoma cells can be reverted to a nonmalignant phenotype by generation of somatic cell hybrids with normal human fibroblasts. although nontumorigenic hybrids, their tumorigenic segregants, and the parental hela cells have similar in vitro properties, inoculation only of nontumorigenic cells into nude mice results in a selective suppression of hpv18 transcription which precedes cessation of cellular growth. our present study, aim ... | 1994 | 8138998 |
| wild-type human p53 activates the human epidermal growth factor receptor promoter. | we show that wild-type human p53 transactivates the human epidermal growth factor receptor (egfr) promoter in vivo in a dose-dependent manner, implicating p53 in promotion of cell proliferation. this activation is sensitive to the expression of cellular oncoprotein mdm2 and human papillomavirus type 18 (hpv-18) e6 protein. the p53 response element is localized within -15 and -569 of the promoter. the egfr promoter does not have a tata box, and has low activity in saos-2 cells in the absence of p ... | 1994 | 8152794 |
| activation of eukaryotic transcriptional promoters by the bovine papillomavirus e1-replication factor. | it has been suggested that the bovine papillomavirus type 1 e1 replication factor may inhibit e2-conditional gene expression from viral promoter p89. to study the possible role of the e1 protein in gene expression, hela cells were transfected with e2-conditional or e2-independent reporter plasmids and with vectors expressing the e1 and e2 open reading frames. the data show that: (i) replication factor e1 stimulates gene expression from a variety of eucaryotic transcriptional promoters; (ii) acti ... | 1993 | 8169116 |
| different stability of ap1 proteins in human keratinocyte and fibroblast cells: possible role in the cell-type specific expression of human papillomavirus type 18 genes. | human papillomaviruses (hpv) replicate in keratinocyte but not fibroblast cells. several factors, including ap1 (jun/fos), contribute to the cell-type specific transcription of hpv genes. the binding of ap1 upstream of the hpv type 18 early gene e6 is essential for transcription of the early genes. here we show that ap1 levels are low in early passage human fibroblast extracts. in contrast, human keratinocyte extracts contain high levels of ap1. in agreement with this, in vivo an ap1-dependent p ... | 1993 | 8269611 |
| differential suppression of the tumorigenicity of hela and siha cells by adeno-associated virus. | adeno-associated virus (aav) is well known for suppression of oncogenesis in rodents, but its inhibitory effects on human carcinoma are less well understood. we report the differential ability of aav to inhibit the tumorigenicity of two human cervical carcinoma cell lines. the wild-type aav-2 dna carried by a psv2neo vector was transfected into hela cells, which contain 50 copies of human papillomavirus type 18 (hpv-18), and siha cells, which contain 1-2 copies of hpv-16. about 1-3 copies of aav ... | 1996 | 8664125 |
| oncogenic human papillomaviruses are rarely associated with squamous cell carcinoma of the bladder: evaluation by differential polymerase chain reaction. | while a strong association between oncogenic human papillomaviruses and squamous cell cancers of the genital tract (penis, urethra and cervix) is known to exist, there is substantial controversy regarding the association of human papillomaviruses and cancers of the bladder. technical issues regarding assay technique and concern about potential contamination have marred interpretation of previous work. moreover, because human papillomavirus has been associated predominantly with squamous cell can ... | 1994 | 8283525 |
| dna damage induced p53 mediated transcription is inhibited by human papillomavirus type 18 e6. | cervical cancer is similar to other human cancers in that it develops through a multistep process. however, infection with oncogenic human papillomaviruses (hpvs) is believed to be essential for the initiation of this disease. although hpv may play a central role in the early stages of neoplasia, the accumulation of mutations in an assortment of genes precedes the development of malignant cervical carcinoma. the mechanisms by which abnormalities accumulate are various, but it is possible that vi ... | 1994 | 8290274 |
| sv40 t antigen abrogates p53-mediated transcriptional activity. | recent evidence suggests that the tumor-suppressor protein p53 functions as a transcriptional regulator to control cell proliferation. an interaction with p53 is required for sv40 t antigen to transform primary cells; however, the effect of t antigen binding on p53 function is not known. in order to determine if an interaction with t antigen results in loss of p53-mediated transcriptional activity, we have used vectors expressing either a p53-gal4 fusion protein or a wild-type p53 protein in tra ... | 1993 | 8378089 |
| alteration of the dcc tumor-suppressor gene in tumorigenic hpv-18 immortalized human keratinocytes transformed by nitrosomethylurea. | a human papillomavirus type 18 (hpv-18)-immortalized human keratinocyte cell line (1811) has been transformed to tumorigenicity in nude mice by treatment with the carcinogen nitrosomethylurea (nmu). the nmu transformants (1811-nmu-t) showed additional chromosome alterations as compared with parental 1811 cells, including 18q deletion in two of two 1811-nmu-t lines analysed. restriction fragment length polymorphism (rflp) analysis indicated that both 1811-nmu-t lines had lost one allele of the 18 ... | 1993 | 8380923 |
| squamous cell carcinoma of the scrotum associated with human papillomaviruses. | a 53-year-old man presented with recurrent squamous cell carcinoma, and dysplasia of the scrotum and penis. risk factors included psoralen and ultraviolet radiation therapy for psoriasis, and x-ray therapy for primary lymphoma of the groin. three different human papillomavirus types were documented using the polymerase chain reaction in distinct anatomical areas. the scrotal carcinoma was associated with human papillomavirus type 18, while regions of dysplasia contained either type 18, 16 or 6/1 ... | 1993 | 8381191 |
| two e2 binding sites alone are sufficient to function as the minimal origin of replication of human papillomavirus type 18 dna. | replication of papillomaviruses requires an origin of replication and two virus-encoded proteins, e1 and e2. using a transient replication assay for human papillomavirus type 18 (hpv-18) dna, we have found that two adjacent sequences present within the origin of replication can independently support replication. the first, a 77-bp region, contains one e2 binding site (e2bs) and a 16-bp inverted repeat element that probably corresponds to the e1 binding site (e1bs). the other, an 81-bp region, in ... | 1995 | 7815514 |