Regulation of HPV transcription

Human papillomavirus infection is associated with the development of malignant and benign neoplasms. Approximately 40 viral types can infect the anogenital mucosa and are categorized into high- and low-risk oncogenic human papillomavirus, depending on their association with the development of cervical carcinoma. High-risk human papillomavirus 16 and 18 are detected in 55% and 15% of all invasive cervical squamous cell carcinomas worldwide, respectively. Low-risk human papillomavirus 6 and 11 are responsible for 90% of genital warts and are also associated with the development of recurrent respiratory papillomatosis. Human papillomavirus preferentially infects mitotic active cells of the basal layer from both mucosal and cutaneous epithelium through microabrasions. The viral life cycle synchronizes with the epithelial differentiation program, which may be due, in part, to the binding of differentially expressed cellular transcription factors to the long control region throughout the various epithelial layers. This review aimed to summarize the current knowledge regarding the mechanisms by which viral gene expression is regulated and the influence of human papillomavirus heterogeneity upon this phenomenon. A better understanding of the regulatory mechanisms may elucidate the particularities of human papillomavirus-associated pathogenesis and may provide new tools for antiviral therapy

Epidemiology and biology of cutaneous human papillomavirus

Cutaneous human papillomaviruses (HPVs) include b- and g-HPVs, in addition to a small fraction of a-HPVs. b-HPVs were first isolated from patients with the rare genetic disorder Epidermodysplasia verruciformis, and they are associated with the development of nonmelanoma skin cancer at sun-exposed skin sites in these individuals. Organ transplant recipients also have greater susceptibility to b-HPV infection of the skin and an increased risk of developing nonmelanoma skin cancer. In both immunosuppressed and immunocompromised individuals, cutaneous HPVs are ubiquitously disseminated throughout healthy skin and may be an intrinsic part of the commensal flora. Functional analysis of E6 and E7 proteins of specific cutaneous HPVs has provided a mechanistic comprehension of how these viruses may induce carcinogenesis. Nevertheless, additional research is crucial to better understand the pathological implications of the broad distribution of these HPVs

Papel cooperativo de c-MYC e E6/E7 de duas variantes moleculares do Papilomavírus Humano tipo 16 na proliferação e transformação in vitro de queratinócitos humanos primários

As funções das oncoproteínas E6 e E7 do Papilomavírus Humano tipo 16 (HPV-16) na progressão de células epiteliais imortalizadas para tumores invasivos não são totalmente compreendidas. Aqui, estabelecemos uma nova ligação entre E6 e E7 de duas variantes moleculares de HPV-16 (AA e E-350G) e c-MYC, em relação à cooperação na promoção da transformação maligna de queratinócitos humano primários de prepúcio de recém-nascido (PHK). Nosso objetivo foi estudar os efeitos sinérgicos de E6/E7 e c-MYC na proliferação e no potencial de transformação in vitro de PHKs. Avaliou-se a proliferação celular através da expressão proteica do Antígeno Nuclear de Células Proliferantes (PCNA). Também avaliamos a capacidade de transformação, in vitro, dos PHKs através de dois ensaios complementares. Observamos que E-350G-c-MYC PHKs exibiram um aumento discreto na expressão de PCNA e formaram significativamente mais colônias tanto nos ensaios de soft-ágar quanto nos ensaios em placas de cultura de baixa adesão. No geral, concluímos que a variante E-350G co-transfectada com c-MYC pode promover a transformação celular maligna com eficiência maior do que a variante AA-c-MYC. As propriedades oncogênicas exibidas pela variante E-350G permitem entender em maior detalhe os mecanismos que podem levar à neoplasia cervical humana, dada a maior frequência de sua ocorrência na progressão de lesões precursoras de alto grau para carcinomas invasivos.The roles of E6 and E7 oncoproteins of Human Papillomavirus type 16 (HPV-16) in the progression of immortalized epithelial cells to invasive tumors are not fully understood. Here, we establish a novel link between E6 and E7 of two molecular variants of HPV-16 (AA and E-350G), and c-MYC, regarding the cooperation in promoting malignant transformation of primary human foreskin keratinocytes (PHK). We aimed to study the synergistic effects of E6/E7 and c-MYC upon proliferation, and the in vitro transformation potential of PHK. We evaluated cellular proliferation through the expression of the Proliferating Cell Nuclear Antigen (PCNA) protein and colony formation abilities using soft agar and low attachment plates. We observed that E-350G-c-MYC PHKs exhibited discrete higher PCNA levels and formed significantly more colonies in both soft-agar and when growth in low-adhesion culture plates. Overall, we concluded that the E-350G variant co-transfected with c-MYC might promote malignant cellular transformation with a better efficiency than the AA-c-MYC counterpart. The enhanced oncogenic properties exhibited by the E-350G-c-MYC variant offer insights into mechanisms that may operate in human cervical neoplasia, given the higher frequency of its occurrence in the progression of high-grade precursor lesions to invasive carcinomas

The relation of HPV infection and expression of p53 and p16 proteins in esophageal squamous cells carcinoma

GOAL: To investigate the HPV prevalence and characterize the expression of potential molecular surrogate markers of HPV infection in esophageal squamous cell carcinoma. MATERIALS AND METHODS: The prevalence of HPV in individuals with and without esophageal cancer (EC) was determined by using multiplex PCR; p16 and p53 protein levels were assessed by immunohistochemistry (IHC). RESULTS: High-risk HPV (hr-HPV) was found in the same frequency (13.8%) in esophageal squamous cell carcinoma (ESCC) and in healthy individuals. The p53 expression was positive in 67.5% of tumor tissue, 20.0% of adjacent non-tumoral tissue and 1.8% of normal esophageal tissue. p16 was positive in 11.6% of esophageal cancer cases and 4.7% of adjacent non-tumoral tissue. p16 was undetectable among control group samples. p53 and p16 levels were not significantly associated with the HPV status. CONCLUSIONS: These results suggest that hr-HPV types are not associated with the development of ESCC and that p53 and p16 protein expression have no relationship with HPV infection in normal or cancerous esophagus.This work was supported by Conselho Nacional de Desenvolvimento Científico e Tencnológico (CNPq) [Grants number 482666/2012-9 to ALF; 573799/2008-3 to LLV]; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) [Grants numbers 13/15968-0 to PRAP; 08/57889-1 to LLV]. CNPq Universal for promoting supplied to the largest study of which this study is part entitled "The role of human papillomavirus (HPV) as the etiologic agent of esophageal cancer. A cross-sectional study, case-control and longitudinal in Barretos Cancer Hospital" (Grant number 482666/2012-9 to ALF); Fundação de Amparo à Pequisa do Estado de São Paulo (FAPESP) (Grant number 13/15968-0 to PRAP); INCT HPV [Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) [Grant number 08/57889-1 to LLV]; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) (Grant number 573799/2008-3 to LLV)]info:eu-repo/semantics/publishedVersio

Dysregulation of Transcription Factor Networks Unveils Different Pathways in Human Papillomavirus 16-Positive Squamous Cell Carcinoma and Adenocarcinoma of the Uterine Cervix

Squamous cell carcinoma (SCC) and adenocarcinoma (ADC) are the most common histological types of cervical cancer (CC). The worse prognosis of ADC cases highlights the need for better molecular characterization regarding differences between these CC types. RNA-Seq analysis of seven SCC and three ADC human papillomavirus 16-positive samples and the comparison with public data from non-tumoral human papillomavirus-negative cervical tissue samples revealed pathways exclusive to each histological type, such as the epithelial maintenance in SCC and the maturity-onset diabetes of the young (MODY) pathway in ADC. The transcriptional regulatory network analysis of cervical SCC samples unveiled a set of six transcription factor (TF) genes with the potential to positively regulate long non-coding RNA genes DSG1-AS1, CALML3-AS1, IGFL2-AS1, and TINCR. Additional analysis revealed a set of MODY TFs regulated in the sequence predicted to be repressed bymiR-96-5p ormiR-28-3p in ADC. These microRNAs were previously described to target LINC02381, which was predicted to be positively regulated by two MODY TFs upregulated in cervical ADC. Therefore, we hypothesize LINC02381might act by decreasing the levels ofmiR-96-5p andmiR-28-3p, promoting the MODY activation in cervical ADC. The novel TF networks here described should be explored for the development of more efficient diagnostic tools

HPV infection and p53 and p16 expression in esophageal cancer: are they prognostic factors?

Background: Esophageal squamous cell carcinoma (ESCC) is a highly lethal malignant tumor. Currently, Human papillomavirus (HPV) is suggested as a potential risk factor for esophageal cancer (EC) in addition to the classic risk factors, alcohol and tobacco, but this hypothesis still remains contradictory. We sought to investigate wether HPV and well-known biomarkers (p16 and p53) and patient-related factors that may have impact on survival of ESCC. Methods: We conducted a prospective cohort study. By using multiplex PCR, we determined the prevalence of high risk HPV in ESCC, and evaluated the immunohistochemical expression of p16 and p53, molecular markers related to esophageal carcinogenesis in order to verify the potential influence of these variables in patients's survival. Survival rates were estimated using Kaplan-Meier methods. A multivariate confirmatory model was performed using Cox proportional hazards regression. Results: Twelve (13.8%) of 87 patients were HPV-DNA positive. Positive reactions of p16 and p53 were 10.7% and 68.6%, respectively. Kaplan-Meier analysis indicated that men (p = 0.025) had poor specific-cancer survival and a shorter progression-free survival (p = 0.050) as compared to women; III or IV clinical stage (p < 0.019) had poor specific-cancer survival and a shorter progression-free survival (p < 0.001) compared to I and II clinical stage; not submitted to surgery (< 0.001) and not submitted to chemoradiotherapy (p = 0.039) had a poor specific-cancer survival, as well. The multivariate analysis showed that HPV, p16 and p53 status are not predictive parameters of progression-free and specific-cancer survival. Conclusion: HPV infection and p53 and p16 expression are not prognostic factors in ESCC.CNPq Universal for providing supplies to the largest study, of which this study is a part of, entitled “The role of human papillomavirus (HPV) as the etiologic agent of esophageal cancer. A cross-sectional study, case-control and longitudinal at Barretos Cancer Hospital”; (Grant number 482666/2012–9 to ALF); INCT HPV [Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) [Grant number 08/57889–1 to LLV]; Conselho Nacional de Desenvolvimento Científico e Tencnológico (CNPq) (Grant number 573799/ 2008–3 to LLV)].info:eu-repo/semantics/publishedVersio

Oncogenic potential of natural variants of human papillomavirus

O principal fator etiológico da neoplasia do colo do útero é a infecção por HPVs (papilomavírus humano) de alto risco oncogênico, principalmente HPVs 16 e 18. A variabilidade intra-típica de ambos tipos virais tem sido extensivamente estudada. A análise da diversidade genética de isolados oriundos de diferentes regiões dos cinco continentes permitiu traçar a origem e filogenia destes vírus, e sugeriu-se que a evolução destes reflete a relação dos mesmos com seu hospedeiro. Considera-se uma variante molecular de um tipo de HPV um genoma que possui 98% ou mais de identidade nos genes Ll , E6 e E7 com um genoma já descrito. Entretanto, variantes moleculares apresentam aproximadamente 5% de diferença na seqüência da LCR (long contral region). Alguns grupos de pesquisa de diferentes partes do mundo relataram a associação epidemiológica entre variantes específicas de HPVs 16 e 18 e o risco aumentado de infecção persistente e de desenvolvimento de lesão do colo uterino de alto grau. No Brasil foi observada a associação positiva entre variantes não-européias de HPVs 16 e 18 e o risco de lesão do colo uterino em um estudo epidemiológico prospectivo que vem sendo conduzido em São Paulo. Neste estudo foi analisada a atividade transcricional dos promotores P97 e P105 de variantes moleculares de HPVs 16 e 18, respectivamente. A variante asiático-americana de HPV-18, B18-3, apresentou a maior atividade transcricional entre todos os isolados testados. Entre as variantes moleculares de HPV-18, o isolado europeu B18-2 foi o menos ativo transcricionalmente. Entre as amostras de HPV-16, a variante européia B-12 foi a que apresentou a maior atividade transcricional. Foi observado, também, que o promotor P105 de HPV-18 é mais ativo transcricionalmente que o promotor P97. Adicionalmente, foi analisada a capacidade de imortalização de queratinócitos humanos primários por E6/E7 de variantes moleculares de HPV-16. Essas variantes não diferiram muito quanto a eficiência de formação de colônias de queratinócitos crescidos em baixa densidade. Entretanto, a variante asiático-americana gerou um maior número de colônias potencialmente imortalizadas. Esses resultados têm implicações importantes na determinação do risco de desenvolvimento de lesões de colo uterino associadas ao HPV.Infection by high-risk HPV (human papillomavirus) types, especially HPVs 16 and 18, is the major etiological factor of cervical neoplasia. Intratypic nucleotide variability of both HPV types has been extensively studied. Genetic diversity analyses of isolates from different regions of the five continents permitted to reconstruct the origin and phylogeny of this virus, and suggested that viral evolution reflects the relation between the virus and their host. A molecular variant of HPV possess 98% or more identity in L1, E6 and E7 genes with another viral genome. However, molecular variants have approximately 5% differences within the LCR (long control region). Some research groups from different parts of the world have described the epidemiologic association between specific variants of HPVs 16 and 18 and increased risk of persistent infection and development of squamous intraepithelial lesions. In Brazil, we observed a positive association between non-European variants of HPVs 16 and 18 and risk of cervical lesion in a prospective epidemiologic study that is being conducted in São Paulo. In this study we analyzed P97 and P105 transcriptional activity of molecular variants of HPVs 16 and 18, respectively. The Asian-American variant of HPV-18, B18-3, exhibited the highest transcriptional activity among all isolates tested. Among HPV-18 molecular variants, the B 18-2 European isolate was the less transcriptionally active. Among HPV-16 samples, the B-12 European variant exhibited the highest transcriptional activity. We also observed that the HPV-18 P105 promoter was more active than the HPV-16 P97 promoter. Furthermore, we analyzed the capacity of immortalization of primary human keratinocytes by E6/E7 molecular variants of HPV-16. These variants did not differ much in the efficiency of colony formation by low density keratinocyte plating. However, the Asian-American variant yielded a higher number of colonies potentially immortalized. These results have important implications in the determination of risk for development of HPV -associated cervical lesions

Oncogenic potential of natural variants of human papillomavirus

O principal fator etiológico da neoplasia do colo do útero é a infecção por HPVs (papilomavírus humano) de alto risco oncogênico, principalmente HPVs 16 e 18. A variabilidade intra-típica de ambos tipos virais tem sido extensivamente estudada. A análise da diversidade genética de isolados oriundos de diferentes regiões dos cinco continentes permitiu traçar a origem e filogenia destes vírus, e sugeriu-se que a evolução destes reflete a relação dos mesmos com seu hospedeiro. Considera-se uma variante molecular de um tipo de HPV um genoma que possui 98% ou mais de identidade nos genes Ll , E6 e E7 com um genoma já descrito. Entretanto, variantes moleculares apresentam aproximadamente 5% de diferença na seqüência da LCR (long contral region). Alguns grupos de pesquisa de diferentes partes do mundo relataram a associação epidemiológica entre variantes específicas de HPVs 16 e 18 e o risco aumentado de infecção persistente e de desenvolvimento de lesão do colo uterino de alto grau. No Brasil foi observada a associação positiva entre variantes não-européias de HPVs 16 e 18 e o risco de lesão do colo uterino em um estudo epidemiológico prospectivo que vem sendo conduzido em São Paulo. Neste estudo foi analisada a atividade transcricional dos promotores P97 e P105 de variantes moleculares de HPVs 16 e 18, respectivamente. A variante asiático-americana de HPV-18, B18-3, apresentou a maior atividade transcricional entre todos os isolados testados. Entre as variantes moleculares de HPV-18, o isolado europeu B18-2 foi o menos ativo transcricionalmente. Entre as amostras de HPV-16, a variante européia B-12 foi a que apresentou a maior atividade transcricional. Foi observado, também, que o promotor P105 de HPV-18 é mais ativo transcricionalmente que o promotor P97. Adicionalmente, foi analisada a capacidade de imortalização de queratinócitos humanos primários por E6/E7 de variantes moleculares de HPV-16. Essas variantes não diferiram muito quanto a eficiência de formação de colônias de queratinócitos crescidos em baixa densidade. Entretanto, a variante asiático-americana gerou um maior número de colônias potencialmente imortalizadas. Esses resultados têm implicações importantes na determinação do risco de desenvolvimento de lesões de colo uterino associadas ao HPV.Infection by high-risk HPV (human papillomavirus) types, especially HPVs 16 and 18, is the major etiological factor of cervical neoplasia. Intratypic nucleotide variability of both HPV types has been extensively studied. Genetic diversity analyses of isolates from different regions of the five continents permitted to reconstruct the origin and phylogeny of this virus, and suggested that viral evolution reflects the relation between the virus and their host. A molecular variant of HPV possess 98% or more identity in L1, E6 and E7 genes with another viral genome. However, molecular variants have approximately 5% differences within the LCR (long control region). Some research groups from different parts of the world have described the epidemiologic association between specific variants of HPVs 16 and 18 and increased risk of persistent infection and development of squamous intraepithelial lesions. In Brazil, we observed a positive association between non-European variants of HPVs 16 and 18 and risk of cervical lesion in a prospective epidemiologic study that is being conducted in São Paulo. In this study we analyzed P97 and P105 transcriptional activity of molecular variants of HPVs 16 and 18, respectively. The Asian-American variant of HPV-18, B18-3, exhibited the highest transcriptional activity among all isolates tested. Among HPV-18 molecular variants, the B 18-2 European isolate was the less transcriptionally active. Among HPV-16 samples, the B-12 European variant exhibited the highest transcriptional activity. We also observed that the HPV-18 P105 promoter was more active than the HPV-16 P97 promoter. Furthermore, we analyzed the capacity of immortalization of primary human keratinocytes by E6/E7 molecular variants of HPV-16. These variants did not differ much in the efficiency of colony formation by low density keratinocyte plating. However, the Asian-American variant yielded a higher number of colonies potentially immortalized. These results have important implications in the determination of risk for development of HPV -associated cervical lesions