Calcium Regulates the Differentiation of Human Papillomavirus Type 16 (HPV16) Immortalized Ectocervical Epithelial Cells, but Not the Expression of the Papillomavirus E6 and E7 Oncogenes

1993 ◽  
Vol 208 (1) ◽  
pp. 161-169 ◽  
Author(s):  
Chee K. Choo ◽  
Ellen A. Rorke ◽  
Richard L. Eckert
Keyword(s):  
Human Papillomavirus ◽  
Epithelial Cells ◽  
Human Papillomavirus Type 16 ◽  
E6 And E7

Restoration of telomeres in human papillomavirus-immortalized human anogenital epithelial cells

1994 ◽  
Vol 14 (2) ◽  
pp. 961-969
Author(s):  
A J Klingelhutz ◽  
S A Barber ◽  
P P Smith ◽  
K Dyer ◽  
J K McDougall
Keyword(s):  
Human Papillomavirus ◽  
Epithelial Cells ◽  
Telomere Length ◽  
Open Reading Frames ◽  
Population Doubling ◽  
Telomere Shortening ◽  
Human Papillomavirus Type 16 ◽  
Immortalized Cells ◽  
E6 And E7

Loss of telomeres has been hypothesized to be important in cellular senescence and may play a role in carcinogenesis. In this study, we have measured telomere length in association with the immortalization and transformation of human cervical and foreskin epithelial cells by the human papillomavirus type 16 or 18 E6 and E7 open reading frames. By using a telomeric TTAGGG repeat probe, it was shown that the telomeres of precrisis normal and E6-, E7-, and E6/E7-expressing cells gradually shortened with passaging (30 to 100 bp per population doubling). Cells that expressed both E6 and E7 went through a crisis period and gave rise to immortalized lines. In contrast to precrisis cells, E6/E7-immortalized cells generally showed an increase in telomere length as they were passaged in culture, with some later passage lines having telomeres that were similar to or longer than the earliest-passage precrisis cells examined. No consistent association could be made between telomere length and tumorigenicity of cells in nude mice. However, of the three cell lines that grew in vivo, two had long telomeres, thus arguing against the hypothesis that cancer cells favor shortened telomeres. Our results indicate that arrest of telomere shortening may be important in human papillomavirus-associated immortalization and that restoration of telomere length may be advantageous to cells with regard to their ability to proliferate.

scholarly journals Restoration of telomeres in human papillomavirus-immortalized human anogenital epithelial cells.

1994 ◽  
Vol 14 (2) ◽  
pp. 961-969 ◽  
Author(s):  
A J Klingelhutz ◽  
S A Barber ◽  
P P Smith ◽  
K Dyer ◽  
J K McDougall
Keyword(s):  
Human Papillomavirus ◽  
Epithelial Cells ◽  
Telomere Length ◽  
Open Reading Frames ◽  
Population Doubling ◽  
Telomere Shortening ◽  
Human Papillomavirus Type 16 ◽  
Immortalized Cells ◽  
E6 And E7

Loss of telomeres has been hypothesized to be important in cellular senescence and may play a role in carcinogenesis. In this study, we have measured telomere length in association with the immortalization and transformation of human cervical and foreskin epithelial cells by the human papillomavirus type 16 or 18 E6 and E7 open reading frames. By using a telomeric TTAGGG repeat probe, it was shown that the telomeres of precrisis normal and E6-, E7-, and E6/E7-expressing cells gradually shortened with passaging (30 to 100 bp per population doubling). Cells that expressed both E6 and E7 went through a crisis period and gave rise to immortalized lines. In contrast to precrisis cells, E6/E7-immortalized cells generally showed an increase in telomere length as they were passaged in culture, with some later passage lines having telomeres that were similar to or longer than the earliest-passage precrisis cells examined. No consistent association could be made between telomere length and tumorigenicity of cells in nude mice. However, of the three cell lines that grew in vivo, two had long telomeres, thus arguing against the hypothesis that cancer cells favor shortened telomeres. Our results indicate that arrest of telomere shortening may be important in human papillomavirus-associated immortalization and that restoration of telomere length may be advantageous to cells with regard to their ability to proliferate.

scholarly journals Targeted expression of the E6 and E7 oncogenes of human papillomavirus type 16 in the epidermis of transgenic mice elicits generalized epidermal hyperplasia involving autocrine factors.

1994 ◽  
Vol 14 (12) ◽  
pp. 8250-8258 ◽  
Author(s):  
P Auewarakul ◽  
L Gissmann ◽  
A Cid-Arregui
Keyword(s):  
Human Papillomavirus ◽  
Growth Factor ◽  
Epithelial Cells ◽  
Transgenic Mice ◽  
Transforming Growth Factor ◽  
Basal Layer ◽  
Epidermal Hyperplasia ◽  
Human Papillomavirus Type 16 ◽  
E6 And E7

The E6 and E7 early genes of human papillomavirus type 16 have been shown in vitro to play a central role in the transforming capability of this virus. To explore their effects on differentiating epithelial cells in vivo, we used a bovine cytokeratin 10 (K10) promoter to target the expression of E6 and E7 to the suprabasal layers of the epidermis of transgenic mice. In two different lines of mice efficiently expressing the transgene, animals displayed generalized epidermal hyperplasia, hyperkeratosis and parakeratosis in the skin and the forestomach, both known to be sites of K10 expression. Northern (RNA) blot analysis revealed high levels of E6 and E7 transcripts, and in situ hybridizations localized these transcripts to the suprabasal strata of epidermis. In vivo labeling of proliferating cells showed two distinct effects of E6 and E7 expression in the epidermis: (i) an increase in the number of growing cells in the undifferentiated basal layer and (ii) abnormal proliferation of differentiated cells in the suprabasal strata. The expression of c-myc in the skin of transgenics was higher than that in control animals. The induction of c-myc transcription by topical application of tetradecanoyl phorbol acetate was prevented by simultaneous treatment with transforming growth factor beta 1 in nontransgenic skin but not in transgenic skin. In addition, transforming growth factor alpha was found to be overexpressed in the suprabasal layers of the transgenic epidermis. These findings suggest that autocrine mechanisms are involved in the development and maintenance of epidermal hyperplasia. Animals of both lines developed papillomas in skin sites exposed to mechanical irritation and wounding, suggesting that secondary events are necessary for progression to neoplasia. Collectively, these results provide new insights into the tumor promoter activities of human papillomavirus type 16 in epithelial cells in vivo.

scholarly journals Functional Interaction between Human Papillomavirus Type 16 E6 and E7 Oncoproteins and Cigarette Smoke Components in Lung Epithelial Cells

PLoS ONE ◽  
2012 ◽  
Vol 7 (5) ◽  
pp. e38178 ◽  
Author(s):  
Juan Pablo Muñoz ◽  
Carolina González ◽  
Bárbara Parra ◽  
Alejandro H. Corvalán ◽  
Maria Lina Tornesello ◽  
...  
Keyword(s):  
Human Papillomavirus ◽  
Epithelial Cells ◽  
Cigarette Smoke ◽  
Lung Epithelial Cells ◽  
Functional Interaction ◽  
Human Papillomavirus Type 16 ◽  
Lung Epithelial ◽  
E6 And E7 Oncoproteins ◽  
E6 And E7

Targeted expression of the E6 and E7 oncogenes of human papillomavirus type 16 in the epidermis of transgenic mice elicits generalized epidermal hyperplasia involving autocrine factors

1994 ◽  
Vol 14 (12) ◽  
pp. 8250-8258
Author(s):  
P Auewarakul ◽  
L Gissmann ◽  
A Cid-Arregui
Keyword(s):  
Human Papillomavirus ◽  
Growth Factor ◽  
Epithelial Cells ◽  
Transgenic Mice ◽  
Transforming Growth Factor ◽  
Basal Layer ◽  
Epidermal Hyperplasia ◽  
Human Papillomavirus Type 16 ◽  
E6 And E7

The E6 and E7 early genes of human papillomavirus type 16 have been shown in vitro to play a central role in the transforming capability of this virus. To explore their effects on differentiating epithelial cells in vivo, we used a bovine cytokeratin 10 (K10) promoter to target the expression of E6 and E7 to the suprabasal layers of the epidermis of transgenic mice. In two different lines of mice efficiently expressing the transgene, animals displayed generalized epidermal hyperplasia, hyperkeratosis and parakeratosis in the skin and the forestomach, both known to be sites of K10 expression. Northern (RNA) blot analysis revealed high levels of E6 and E7 transcripts, and in situ hybridizations localized these transcripts to the suprabasal strata of epidermis. In vivo labeling of proliferating cells showed two distinct effects of E6 and E7 expression in the epidermis: (i) an increase in the number of growing cells in the undifferentiated basal layer and (ii) abnormal proliferation of differentiated cells in the suprabasal strata. The expression of c-myc in the skin of transgenics was higher than that in control animals. The induction of c-myc transcription by topical application of tetradecanoyl phorbol acetate was prevented by simultaneous treatment with transforming growth factor beta 1 in nontransgenic skin but not in transgenic skin. In addition, transforming growth factor alpha was found to be overexpressed in the suprabasal layers of the transgenic epidermis. These findings suggest that autocrine mechanisms are involved in the development and maintenance of epidermal hyperplasia. Animals of both lines developed papillomas in skin sites exposed to mechanical irritation and wounding, suggesting that secondary events are necessary for progression to neoplasia. Collectively, these results provide new insights into the tumor promoter activities of human papillomavirus type 16 in epithelial cells in vivo.

E6 and E7 Oncoproteins from Human Papillomavirus Type 16 Induce Activation of Human Transforming Growth Factorβ1Promoter throughout Sp1 Recognition Sequence

2006 ◽  
Vol 19 (3) ◽  
pp. 468-480 ◽  
Author(s):  
Oscar Peralta-Zaragoza ◽  
Víctor Bermúdez-Morales ◽  
Lourdes Gutiérrez-Xicotencatl ◽  
Juan Alcocer-González ◽  
Félix Recillas-Targa ◽  
...  
Keyword(s):  
Human Papillomavirus ◽  
Recognition Sequence ◽  
Human Papillomavirus Type 16 ◽  
E6 And E7 Oncoproteins ◽  
E6 And E7

scholarly journals Multiple ASF/SF2 Sites in the Human Papillomavirus Type 16 (HPV-16) E4-Coding Region Promote Splicing to the Most Commonly Used 3′-Splice Site on the HPV-16 Genome

2010 ◽  
Vol 84 (16) ◽  
pp. 8219-8230 ◽  
Author(s):  
Monika Somberg ◽  
Stefan Schwartz
Keyword(s):  
Cervical Cancer ◽  
Human Papillomavirus ◽  
Splice Site ◽  
Binding Sites ◽  
Mrna Levels ◽  
Coding Region ◽  
Cervical Lesions ◽  
Hpv 16 ◽  
Human Papillomavirus Type 16 ◽  
E6 And E7

ABSTRACT Our results presented here demonstrate that the most abundant human papillomavirus type 16 (HPV-16) mRNAs expressing the viral oncogenes E6 and E7 are regulated by cellular ASF/SF2, itself defined as a proto-oncogene and overexpressed in cervical cancer cells. We show that the most frequently used 3′-splice site on the HPV-16 genome, site SA3358, which is used to produce primarily E4, E6, and E7 mRNAs, is regulated by ASF/SF2. Splice site SA3358 is immediately followed by 15 potential binding sites for the splicing factor ASF/SF2. Recombinant ASF/SF2 binds to the cluster of ASF/SF2 sites. Mutational inactivation of all 15 sites abolished splicing to SA3358 and redirected splicing to the downstream-located, late 3′-splice site SA5639. Overexpression of a mutant ASF/SF2 protein that lacks the RS domain, also totally inhibited the usage of SA3358 and redirected splicing to the late 3′-splice site SA5639. The 15 ASF/SF2 binding sites could be replaced by an ASF/SF2-dependent, HIV-1-derived splicing enhancer named GAR. This enhancer was also inhibited by the mutant ASF/SF2 protein that lacks the RS domain. Finally, silencer RNA (siRNA)-mediated knockdown of ASF/SF2 caused a reduction in spliced HPV-16 mRNA levels. Taken together, our results demonstrate that the major HPV-16 3′-splice site SA3358 is dependent on ASF/SF2. SA3358 is used by the most abundantly expressed HPV-16 mRNAs, including those encoding E6 and E7. High levels of ASF/SF2 may therefore be a requirement for progression to cervical cancer. This is supported by our earlier findings that ASF/SF2 is overexpressed in high-grade cervical lesions and cervical cancer.

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