Effect Of Human Papillomavirus Type Research Articles

Potential water-based extracts from fresh and dried auricularia auricula-judaeon the inhibitory effect of human papillomavirus type 16 and cervical cancer cell line in caski

Auricularia auricula-judae, also called the wood ear mushroom, is a well-known edible mushroom in various countries. Notably, the extracts of this mushroom inhibited the growth and expression of human papillomavirus (HPV) oncogene in the HPV-positive cervical cancer cell line. However, there has been no reported comparison of the effect of the extracts from fresh and dried A. auricula-judae on anti-HPV16 in CaSki cell lines. Thus, this study investigated the effect of the water-based extracts from fresh and dried A. auricula-judae at 100oC on anti-HPV16 pseudovirus infection and anti-cancer in CaSki as well as the expression of viral oncogenes and cellular genes. HPV16 pseudovirus was produced and used for anti-viral infection assay in pre-attachment and adsorption steps in treated 293FT cells. Cell apoptosis, cell proliferation, cell migration and colony-forming assay were investigated in treated CaSki cells. In addition, mRNA expression levels of HPV16E6/E7, BCL2, BAK and CASP3 were determined using quantitative real time polymerase chain reaction. The results indicated that the extract from dried mushroom caused higher cytotoxicity than fresh mushroom. Notably, the extracts from the dried mushroom more effectively inhibited the infection of HPV16 pseudovirus in 293FT cells than did fresh mushroom. Furthermore, it significantly decreased HPV16E6/E7 and BCL2 and increased BAK and CASP3 expression, in contrast to the untreated and water-treated CaSki cells, but not in the extract derived from fresh mushroom. The main conclusion was that the extract from dried mushroom more effectively inhibited growth of CaSki and HPV16-pseudovirus infection than from fresh mushroom.

Effects of human papillomavirus type 16 E5 deletion mutants on epithelial morphology: functional characterization of each transmembrane domain

Human papillomavirus type 16 (HPV-16) is the cause of cervical cancer. The HPV genome encodes three transforming proteins, E5, E6 and E7. E6 and E7 are the main transforming proteins of HPV, while the role of E5 is still poorly understood. Using three dimensional organotypic raft cultures we show that HaCaT human keratinocytes expressing HPV-16 E5 form a very perturbed epithelium, with simultaneous hyperkeratinization of some cells and defective differentiation of other cells. The basal layer is disturbed and many cells invade the collagen matrix. Many cells among the differentiated layers show characteristics of basal cells: progression through the cell cycle, expression of cytokeratin 14, lack of cytokeratin 1 and production of matrix metalloproteases (MMP). Using deletion mutants which encompass the three hydrophobic domains of E5, we have assigned the ability to promote invasion of the matrix to the first hydrophobic domain, and the capacity to induce MMP9 to the C-terminal four amino acids. We also show that invasion and production of MMP9 can be dissociated, as mutants that are still capable of invasion do not produce MMP9 and vice versa.

Effects of human papillomavirus type 16 oncoproteins on survivin gene expression

Survivin has recently been identified as a novel member of the inhibitor of apoptosis (IAP) gene family. The product of this gene not only suppresses apoptosis but also controls cell division. Survivin is undetectable in most terminally differentiated normal tissues but is expressed in embryonic and fetal organs and is present in most malignant tumours. Human papillomaviruses (HPV) are thought to play an important role in the development of cervical cancer. By interfering in the cell cycle, the viral oncoproteins (E6 and E7) can induce the immortalization of the host cell. The transcriptional effects of the HPV-16 E6 and E7 proteins on the survivin promoter in transiently transfected cell lines using luciferase tests were examined. HPV-16 E6, but not E7, was found to significantly transactivate the survivin promoter. Experiments performed in different cancer cell lines and with different E6 mutants indicated that the effect of E6 on the survivin promoter is largely dependent on p53 status. In accordance with this, the p53 tumour suppressor protein downregulated the expression of survivin. As E6 is able to interact with p53 and induces its ubiquitin-dependent degradation, it appears that the transactivation effect of E6 on survivin is mediated by the p53 degradation pathway. Transduction of HPV-16 E6 and E7 into human embryonic fibroblast cells showed that the HPV oncoproteins can upregulate endogenous survivin mRNA. Importantly, cell cycle synchronization experiments showed that the effect of HPV-16 E6 on survivin transcription is independent of the cell cycle.

Effects of human papillomavirus type 16 E7 protein on the growth of cervical carcinoma cells and immuno-escape through the TGF-β1 signaling pathway

Objective.E7 is regarded as one of the main oncoproteins of high-risk human papillomaviruses (HPVs). It may affect the transforming growth factor beta 1 (TGF-β1) signaling pathway. In this study, the relationship between HPV-16 infection and the functions of three critical factors of the TGF-β1/Smads pathway was explored to assess the possible role of E7 in the development of cervical cancer. Methods.The expression of E7, TGF-β1, TβR-II and Smad4 was detected by immunohistochemistry in paraffin-embedded cervical samples, and by RT-PCR and Western blotting in cervical cancer cell lines. The effect of TGF-β1 on the growth of cervical cancer cells were tested by methyl thiazolyl tetrazolium (MTT), and the effects of HPV-16 E7 protein on normal and malignant cervical cells were investigated by flow cytometry. Results.During the progression from benign to malignant lesions, the expression levels of TGF-β1 and Smad4 increased significantly in cervical carcinoma tissues. The expression of TGF-β1 was positively correlated with E7 expression. In vitro experiments showed that TGF-β1 could not inhibit the proliferation of several cervical carcinoma cell lines in long-term regulation, but could inhibit immunologic reactions of peripheral blood mononuclear cells (PBMCs). Blocking E7 expression could lower the expression level of TGF-β1 and induce cells to enter apoptosis. Conclusions.Our data indicate that HPV-16 E7 protein plays an important role during the development of cervical cancer by immuno-inhibition and stimulation of tumor cell proliferation through the TGF-β1/Smads signaling pathway.

Spontaneous Regression of High-Grade Cervical Dysplasia: Effects of Human Papillomavirus Type and HLA Phenotype

Persistent infection with oncogenic human papillomaviruses (HPV) plays a central etiologic role in the development of squamous carcinomas of the cervix and their precursor lesions, cervical intraepithelial neoplasias (CIN). We carried out a prospective observational cohort study evaluating known, quantifiable prognostic variables of clinical behavior in women with high-grade cervical lesions. Our study cohort included healthy women with high-grade cervical lesions (CIN2/3) with residual visible lesions after colposcopically directed biopsy. We prospectively followed 100 women over 15 weeks before standard resection. HPV typing was done using PCR and a reverse line blot detection method. The rate of spontaneous histologic regression, defined as (CIN1 or less at resection) was 28%. The overall rate of HPV infection was 100%. HPV16 was identified in 68% of the lesions. Women with HPV16 only were significantly less likely to regress, compared with women with HPV types other than HPV16 (odds ratio, 0.342; 95% confidence interval, 0.117-0.997; P = 0.049). In the cohort with HPV16 only, patients who had an HLA*A201 allele had similar outcomes to those who did not carry A201. However, among patients with HPV types other than HPV16, the HLA*A201 allele interaction was significant; patients with HLA*A201 were the least likely to resolve. CIN2/3 lesions associated with HPV16 alone are significantly less likely to resolve spontaneously than those caused by other types. Interactions among HPV type, HLA type, and regression rate support a role for HLA-restricted HPV-specific immune responses in determining disease outcome.

Global effects of human papillomavirus type 18 E6/E7 in an organotypic keratinocyte culture system.

The effects of human papillomavirus type 18 (HPV-18) E6 and E7 proteins on global patterns of host gene expression in primary human keratinocytes grown in organotypic raft culture system were assessed. Primary human keratinocytes were infected with retroviruses that express the wild-type HPV-18 E6 and E7 genes from the native differentiation-dependent HPV enhancer-promoter. Total RNA was isolated from raft cultures and used to generate probes for querying Affymetrix U95A microarrays, which contain >12,500 human gene sequences. Quadruplicate arrays of each E6/E7-transduced and empty vector-transduced samples were analyzed by 16 pairwise comparisons. Transcripts altered in > or =12 comparisons were selected for further analysis. With this approach, HPV-18 E6/E7 expression significantly altered the expression of 1,381 genes. A large increase in transcripts associated with DNA and RNA metabolism was observed, with major increases noted for transcription factors, splicing factors, and DNA replication elements, among others. Multiple genes associated with protein translation were downregulated. In addition, major alterations were found in transcripts associated with the cell cycle and cell differentiation. Our study provides a systematic description of transcript changes brought about by HPV-18 E6/E7 in a physiologically relevant model and should furnish a solid source of information to guide future studies.

Effect of human papillomavirus type 16 E6 and E7 oncogenes on the activity of the transforming growth factor-beta2 (TGF-beta2) promoter.

The effect of the human papillomavirus type 16 (HPV 16) E6 and E7 proteins was studied on the transcriptional activity of the human transforming growth factor beta2 (TGF-beta) promoter in different cell lines. Luciferase tests were performed after co-transfection of cells with TGF-beta2 reporter constructs and HPV 16 E6 or E7 expression vectors. HPV 16 E7, but not E6 significantly repressed TGF-beta2 promoter activity in NIH/3T3 cells, which have wild-type p53 and pRb proteins. The repressive effect of HPV 16 E7 on the transcriptional activity of the TGF-beta2 promoter could be localized to the promoter region -528 to -251 relative to the transcriptional start site. Ability of E7 to bind pRb was necessary to inhibit the TGF-beta2 promoter. Over-expression of the transcription factor E2F-1 had an effect on the TGF-beta2 promoter similar to that of E7, which may indicate that HPV 16 E7 represses the TGF-beta2 promoter by releasing E2F from pRb.

Differential effects of human papillomavirus type 6, 16, and 18 DNAs on immortalization and transformation of human cervical epithelial cells.

The human papillomaviruses (HPVs) are associated with specific benign and malignant lesions of the skin and mucosal epithelia. Cloned viral DNAs from HPV types 6b, 16, and 18 associated with different pathological manifestations of genital neoplasia in vivo were introduced into primary human cervical epithelial cells by electroporation. Cells transfected with HPV16 or HPV18 DNA acquired indefinite lifespans, distinct morphological alterations, and anchorage-independent growth (HPV18), and contain integrated transcriptionally active viral genomes. HPV6b or plasmid electroporated cells senesced at low passage. The alterations in growth and differentiation of the cells appear to reflect the progressive oncogenic processes that result in cervical carcinoma in vivo.