O HPV (Papilomavírus Humano) causa verrugas anogenitais e alguns tipos de câncer, como o câncer de colo do útero. Seu capsídeo é composto pelas proteínas L1 e L2. A L1 se autoestrutura em VLPs, utilizadas nas atuais vacinas comerciais. Para a geração de vacinas com maior espectro de proteção, a L2 é promissora, pois gera proteção cruzada. Para caracterizar VLPs de L1L2 do HPV16, células HEK293T cotransfectadas tiveram a expressão proteica analisada por citometria de fluxo, Western blotting, microscopia confocal a laser e eletrônica de transmissão. As proteínas L1 (60kDa) e L2 (100kDa) estavam presentes no núcleo e no citoplasma celular, formando VLPs de L1L2 de conformação heterogênea, cuja máxima expressão ocorre 12h após a transfecção. As VLPs extraídas estavam em diferentes estágios de estruturação. Foi possível estabelecer um sistema eficaz de produção heteróloga das proteínas de VLPs de L1L2, que poderão ser utilizadas em testes pré-clínicos, na pesquisa básica e contribuir no desenvolvimento de uma vacina profilática de amplo espectro de ação contra o HPV. / HPV (Human Papillomavirus) is the causative agent of anogenital warts and several types of cancer, as cervical cancer. The HPV capsid is composed of L1 and L2 proteins. L1 can self-assemble into VLPs (virus-like particles), the basis for HPV commercially available vaccines. To generate broad-spectrum vaccines L2 shows the greatest promise, due to cross-protection. To characterize VLPs composed of HPV16 L1 and L2 proteins, cotransfected HEK293T cells were analyzed by flow cytometry, confocal laser scanning microscopy, transmission electron microscopy and Western blotting. Proteins L1 (60kDa) and L2 (100kDa) were present in cell nucleus and cytoplasm, forming heterologous L1L2 VLPs with highest expression at 12h post-transfection. Extracted VLPs were at different maturation stages. It was possible to establish an efficient system of heterologous L1, L2 and L1L2 VLPs production. After some adjustments in protocols, these particles could be used in preclinical tests, HPV basic research and also in the development of an HPV broad-spectrum vaccine.

Cervical cancer rates in Sub-Saharan Africa (SSA) are amongst the highest in the world. The World Health Organization currently estimates that worldwide, cervical cancer will kill more than 443,000 women per year by 2030, of which 90% of deaths are predicted to occur in SSA. The Human Papillomavirus (HPV) vaccine provides primary protection against the most common cancer-causing strains of HPV that are responsible for cervical cancer. Over the last five years, there has been a slow increase in the number of African countries that have introduced the HPV vaccine via demonstration and pilot projects, and a minority of African countries that have incorporated the HPV vaccine into their National Immunisation Programmes. As part of this systematic review, a literature review was conducted and revealed that research has been conducted on top-down barriers and facilitators to HPV vaccine uptake and have found that poor health system capabilities, inaccessibility to medical care, low cervical cancer screening levels, inadequate infrastructure, finances, and health worker training are significant systemic barriers to HPV vaccination success in SSA. Little research has been conducted on demand-side or end-user perspectives of, and decisions around, the HPV vaccine. In order to complement existing research, and inform current and future implementation approaches, this qualitative systematic review explored stakeholder understandings of the HPV vaccine in SSA. This review searched the following databases: Embase (via Scopus), Scopus, MEDLINE (via PubMed), PubMed, EBSCOhost, Academic Search Premier, Africa-Wide Information, CINAHL, PsycARTICLES, PsycINFO, SocINDEX, Web of Science, and the Cochrane Controlled Register of Trials (CENTRAL) and found a total of 259 articles. Of these, 31 articles met the inclusion and exclusion criteria and were included in the review. Braun and Clarke’s six step process for conducting a thematic analysis was used for analysis and studies were assessed for quality using the Critical Appraisal Skills Programme (CASP) checklist. Three major themes emerged from the thematic analysis: knowledge is intertwined with misinformation; fear shapes contradictory perceptions about the HPV vaccine; and social norms and gender dynamics are relevant factors in how stakeholders understand the HPV vaccine in SSA. This review iterates the importance of first working with communities to gauge understandings of the HPV vaccine, before trying to implement change through education, sensitization and behavior change.

No description available.

Submitted by Ana Lúcia Torres (bfmhuap@gmail.com) on 2017-09-20T16:15:05Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) CAROLINE ALVES DE OLIVEIRA MARTINS - 26maio17.pdf: 1666643 bytes, checksum: 8ad42932894d5839e10e1193c357a64b (MD5) / Approved for entry into archive by Ana Lúcia Torres (bfmhuap@gmail.com) on 2017-09-20T16:15:15Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) CAROLINE ALVES DE OLIVEIRA MARTINS - 26maio17.pdf: 1666643 bytes, checksum: 8ad42932894d5839e10e1193c357a64b (MD5) / Made available in DSpace on 2017-09-20T16:15:15Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) CAROLINE ALVES DE OLIVEIRA MARTINS - 26maio17.pdf: 1666643 bytes, checksum: 8ad42932894d5839e10e1193c357a64b (MD5) Previous issue date: 2017 / Hospital Federal de Bonsucesso / O objetivo do estudo foi analisar a relação entre os diversos fatores de risco para infecção pelo vírus do Papiloma Humano (HPV) e suas lesões, avaliar a prevalência de câncer e das lesões precursoras do trato genital inferior e da infecção por HPV em mulheres transplantadas, além dos tipos mais prevalentes de HPV. Com este fim, foi realizado um estudo transversal com uma amostra aleatória de 61 pacientes. Os resultados encontrados foram: 10 casos de lesão (16.4%), uma prevalência geral de infecção por HPV de 54.5%, e o HPV 16 como o tipo de HPV de alto risco mais encontrado, seguido pelo HPV 51/53/70. Observou-se também, através da realização de regressão logística múltipla, a associação, com significância estatística, entre o uso de hormônio e ocorrência de infecção por HPV de alto risco (p = 0.037). Não foi observada associação, com significância estatística, entre os diversos fatores e a ocorrência de lesões. A imunossupressão foi considerada fator determinante para ocorrência de lesões. O HPV 16 foi o tipo mais frequente observado nas pacientes com e sem lesão. A maior prevalência foi observada na faixa etária entre 31 e 54 anos. Desta forma, observa-se que a alta prevalência de infecção por HPV e de suas lesões precursoras, em relação à literatura, confirmam a importância do rastreio e seguimento diferenciados das pacientes transplantadas. / This study aimed to analyze the relationship between several risk factors for human papillomavirus (HPV) infection and its lesions and to assess the prevalence of lower genital tract precursor lesions, cancer, and HPV infection in female transplant recipients, besides the most prevalent HPV types. The methodology adopted was a cross-sectional study with a random sample of 61 patients. The results found were: 10 cases (16.4%) of lesions, 54.5% of the overall prevalence of HPV infection, and that HPV 16 was the most common high-risk HPV type, followed by HPV 51/53/70. A multiple logistic regression was done, and hormone use presented a statistically significant association with high-risk HPV infection (p = 0.037). No statistically significant association was identified for the set of all factors with the lesions studied. immunosuppression was considered the determining factor for the occurrence of lesions. HPV 16 was the most frequent type observed in patients with and without lesion. The highest prevalence was observed in the age group between 31 and 54 years. Therefore, it was observed the high prevalence of HPV infection and its precursor lesions confirmed the importance of differential screening and follow-up of transplanted patients.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2005. / Härtill 4 uppsatser.

Made available in DSpace on 2011-05-04T12:36:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2010 / O estudo teve por objetivo analisar as questões levantadas na literatura sobre a associação entre o HPV e o câncer do colo uterino e suas implicações para a política de controle da doença. Buscou-se correlacionar esta discussão com antigas polêmicas entre modelos teóricos divergentes sobre etiologia e as medidas de controle por eles prescritas. Trata-se de uma revisão de artigos científicos com abordagem histórica/conceitual acerca das mudanças recentes no conhecimento científico relacionado à etiologia do câncer do colo do útero. A análise do estudo se deu mediante um diálogo entre o discurso produzido pela epidemiologia e pela biologia molecular sobre a gênese do câncer do colo uterino e a reflexão que vem sendo realizada pela Saúde Pública, tendo como eixo temático a crítica ao modelo ainda hegemônico a respeito da etiologia das doenças, focada na especificidade causal e, de acordo com esta, na generalização de intervenções para prevenção e controle. O caso da relação etiológica entre o HPV e o câncer do colo uterino ilustra bem as características e os limites deste modelo, hegemônico desde o final do século XIX. Apesar dos avanços obtidos na compreensão sobre a etiologia das doenças, a lógica das estratégias de controle não tem acompanhado tais avanços. Ainda que as pesquisas sobre a etiologia deste câncer assinalem haver uma complexa rede de interações entre o agente viral e a célula do colo uterino, o modelo hegemônico insiste em privilegiar uma medida específica de intervenção para o controle do câncer, a vacina contra os tipos de HPV de alto-risco. A comprovação do papel de um agente infeccioso na carcinogênese do colo uterino reforça a fragilidade dos limites teóricos que diferenciam os conceitos de doenças transmissíveis e não transmissíveis. Neste contexto, o desenvolvimento da biologia molecular abre novos caminhos e possibilidades de interpretação do fenômeno patológico, aproximando-se da perspectiva daqueles que há muito tempo já buscaram compreendê-lo em uma referência de maior complexidade. A Saúde Pública e a Epidemiologia estiveram na vanguarda de uma postura racional mais ampla sobre a etiologia das doenças, quando aliaram o conhecimento biológico disponível a aspectos sociais e culturais. Os desafios atuais demandam o esforço de integrar a biologia molecular a outros níveis de determinação das doenças, como forma de aprofundar a compreensão dos vínculos complexos entre eles e de buscar alternativas apropriadas de intervenção. / The study aimed to examine the issues raised in the literature on the association between HPV and cervical cancer and its implications for the politics of disease control. We attempted to correlate this discussion with old controversies between different theoretical models about etiology and control measures prescribed by them. This is a review of scientific articles with historical/conceptual approach about recent changes in scientific knowledge related to the etiology of cervical cancer. The study analysis was made by a dialogue between the discourse of the epidemiology and molecular biology about genesis of cervical cancer and the reflection that is being conducted by Public Health, with its central theme the critique of hegemonic still model on the etiology disease, focusing on causal specificity and, according to this, on the generalization of interventions for prevention and control. The case of the etiologic relationship between HPV and cervical cancer illustrates the characteristics and limits of this model, hegemonic since the late nineteenth century. Despite advances in understanding the etiology of diseases, the logic of control strategies has not accompanied these advances. Although research on the etiology of this cancer points that there is a complex network of interactions between the viral agent and the cell of the cervix, the hegemonic model insists on emphasizing a specific measure of intervention for the control of cancer, the vaccine against HPV types high-risk. The evidence of role of an infectious agent in carcinogenesis of the cervix increases the fragility of the theoretical limits that differentiate the concepts of communicable and non-communicable diseases. In this context, the development of molecular biology opens new avenues and possibilities for interpretation of pathological phenomenon, approaching from the perspective of those who long have sought to understand it on a reference of greater complexity. The Public Health and Epidemiology were in the vanguard of rational stance broader on the etiology of disease, when they allied the biological knowledge available with to social and cultural aspects. The current challenges require the effort for integrate the molecular biology with others levels of determine of diseases as a way to deepen understanding of the complex links between them and to seek suitable alternatives for intervention.

Les papillomavirus sont des virus à ADN qui infectent la peau et les muqueuses. Ils causent des verrues et peuvent aussi mener au développement de cancers, dont le cancer du col de l’utérus. La réplication de leur génome nécessite deux protéines virales : l’hélicase E1 et le facteur de transcription E2, qui recrute E1 à l’origine de réplication virale. Pour faciliter l’étude de la réplication du génome viral, un essai quantitatif et à haut débit basé sur l’expression de la luciférase a été développé. Parallèlement, un domaine de transactivation a été identifié dans la région régulatrice N-terminale de la protéine E1. La caractérisation de ce domaine a montré que son intégrité est importante pour la réplication de l’ADN. Cette étude suggère que le domaine de transactivation de E1 est une région protéique intrinsèquement désordonnée qui permet la régulation de la réplication du génome viral par son interaction avec diverses protéines. / Papillomaviruses are small DNA viruses that infect skin and mucosa. They cause warts and can also lead to the development of cancers, including cervical cancer. Replication of their genome requires two viral proteins: the E1 helicase and the E2 transcription factor, which recruits E1 to the viral origin of replication. To facilitate the study of viral genome replication, a quantitative and high-throughput assay based on luciferase expression has been developed. In parallel, a transactivation domain has been identified in the N-terminal regulatory region of the E1 protein. Characterization of this domain showed that its integrity is important for DNA replication. This study suggests that the E1 transactivation domain is an intrinsically unstructured protein region that allows regulation of viral genome replication by its interaction with diverse proteins.

En utilisant une technique originale de détection et de quantification des HPV16 et 18 par PCR duplex, ce travail de thèse illustre la signification, l’intérêt et les limites de l’utilisation clinique de la mesure de la charge virale pour ces deux types d’hrHPV. Si nous n’avons pas démontré de réelle signification de la charge virale en HPV18, il n’en est pas de même pour l’HPV16 dont la charge virale augmente avec la sévérité des lésions constatées. Néanmoins, l’extrême variabilité des charges virales mesurées limite son utilisation en pratique clinique. Après un frottis cervico-utérin (FCU) anormal, une charge virale seuil en HPV16 à 3,0x106 copies par millions de cellules permet la prédiction optimale de la présence d’une CIN2+ (spécificité : 91 % et sensibilité : 58,2 %). Cette valeur seuil est particulièrement performante pour les patientes ayant un FCU de bas grade (spécificité : 96,4 % et sensibilité : 88 %). Si la charge virale en HPV16 et 18 ne semble pas être prédictive de la clairance virale chez les jeunes femmes de moins de 30 ans ayant un FCU normal, elle l’est chez les patientes HPV16 positives ayant une colposcopie normale malgré un FCU équivoque ou de bas grade (spécificité : 86,7 % et sensibilité : 85,7 %). / Using duplex PCR technique for the detection and quantification of HPV16 and 18, this work investigates the significance, value and limitations of the use of HPV16 and 18 viral load quantitation in routine clinical practice. Although HPV18 viral load was not found to be of any clinical relevance, HPV16 viral load was found to significantly increase with the severity of cervical lesions. However, the wide range of viral load observed strongly limitates its use in routine clinical practice. After an abnormal cervical cytology, a HPV16 viral load cut-off of 3.0x106 copies per million cells allows for the best prediction of CIN2+ (91% specificity and 58.2% sensitivity). Such cut-off is particularly efficient in case of low grade abnormal cytology (96.4% specificity and 88% sensitivity). Although HPV16 viral load does not appear to predict for HPV16 clearance in women under 30 with normal cytology, such prediction was observed among women with normal colposcopy following equivocal or low grade cytology (86.7% specificity and 85.7% sensitivity).

Les papillomavirus humains (HPV) sont des virus à ADN double brin qui infectent la peau et les muqueuses. Les infections par les HPV, bien que majoritairement asymptomatique, provoquent des défauts de prolifération cellulaire pouvant parfois générer des cancers. Selon leur pouvoir carcinogène, on distingue les HPV à bas risque oncogène (HPV-BR) provoquant des lésions bénignes, et les HPV à haut risque (HPV-HR) responsables de l’apparition de nombreux cancers ano-génitaux et de certains cancers des voies aéro-digestives supérieures. Parmi les HPV-HR, HPV16 est le plus prévalent. La carcinogenèse induite par les HPV-HR est corrélée à l’expression des protéines virales E6 et E7, qui dérégulent de nombreux processus cellulaires. L’expression des gènes viraux, réalisée par la machinerie de la cellule hôte, est finement régulée particulièrement au niveau posttranscriptionnel. En outre, l’épissage alternatif génère une vingtaine de transcrits viraux, permettant l’expression des protéines virales. L’épissage au sein de la région codante E6 permettant de former l’isoforme E6*I est présent uniquement chez les HPV-HR, mais pas chez les HPV-BR, ce qui suggère son implication dans la carcinogenèse induite par les HPV-HR. Toutefois, le rôle biologique de la protéine E6*I produite par les HPV-HR est encore controversé.Afin de mieux appréhender les mécanismes de la carcinogenèse induite par les HPV-HR, nous nous sommes intéressés à : (i) l’étude des fonctions biologiques de l’isoforme E6*I, et (ii) aux mécanismes impliqués dans la régulation de l’expression de E6 et E7.Pour appréhender le rôle biologique d’E6*I d’HPV16, nous avons utilisé le séquençage de l’ARN afin d’identifier des cibles dérégulées par son expression ectopique. L’expression des isoformes E6 et E6*I d’HPV16 dans des cellules HPV négatives dérégule des transcrits impliqués dans des processus biologiques relatifs à l’expression des gènes viraux, la carcinogenèse virale, la transduction du signal et la traduction. L’expression d’E6*I seule, dérégule des transcrits impliqués dans l’organisation de la matrice extracellulaire, des voies de signalisation et d’adhérence cellulaire. De façon intéressante, il a été montré que ces gènes dérégulés par l’expression d’E6*I sont communément affecté par le niveau intracellulaire de ROS (espèces réactives de l’oxygène). Cela corrobore le rôle d’E6*I dans l’augmentation de la production de ROS. Le stress oxydatif associé aux ROS pourrait favoriser l’intégration du génome viral à celui de la cellule hôte, caractéristique de carcinogenèse associée aux HPV-HR. En somme, E6*I pourrait avoir un rôle oncogénique indépendant de celui d’E6, et interviendrait dans la carcinogenèse associée aux HPV-HR.Nous avons aussi étudié le rôle du complexe de jonction des exons (EJC), dans la régulation posttranscriptionnelle de l’expression d’E6 et E7. L’EJC est un complexe multiprotéique déposé sur les ARNm via l’épissage influençant ainsi leur devenir. Nous avons montré qu’un facteur de l’EJC, eukaryotic initiation factor 4A3 (eIF4A3), se liait aux ARNm viraux. Par ailleurs, nous avons observé que les composants de l’EJC affectent, certes de différentes façons, l’expression d’E6 et E7. Enfin, nous avons aussi étudié l’effet du nonsense-mediated mRNA decay (NMD), un mécanisme lié à l’EJC, sur l’expression d’E6 et E7. Non seulement nos résultats suggèrent que le NMD inhibe l’expression d’E6 et E7, mais nous avons aussi observé que la protéine E6 d’HPV16 réduit l’activité du NMD. Cette inhibition permettrait à HPV16 d’avoir un contrôle sur ses transcrits mais d’affecter aussi des cibles cellulaires du NMD. Etant donné l’implication des gènes régulés par le NMD dans le maintien de l’homéostasie et l’adaptation cellulaires, il serait intéressant d’appréhender le rôle de cette nouvelle activité d’E6 dans la carcinogenèse associée aux HPV-HR. / Human papillomaviruses (HPV) are double strand DNA viruses that infect skin and mucosa. HPV infections, although mostly asymptomatic, cause cell proliferation defects that can sometimes give rise to cancer. According to their carcinogenic potential, we distinguish low-risk HPVs (lr-HPV) causing benign lesions, and high-risk HPV (hr-HPV) responsible for the appearance of numerous anogenital and some head and neck squamous-cell cancers. Among the hr-HPV, HPV16 is the most prevalent. Hr-HPV-induced carcinogenesis is correlated with the expression of the viral oncoproteins, E6 and E7, which deregulate many cellular processes. Viral gene expression, performed by the host cell machine, is finely regulated particularly at the post-transcriptional level. Besides, alternative splicing generates about twenty viral transcripts, leading to the expression of viral proteins. The splicing within the E6 open reading frame that generates an E6*I mRNA only in hr-HPV, but not in the lr-HPV, suggests its involvement in hr-HPV-induced carcinogenesis. However, the biological role of E6*I protein produced by HPV-HR is still controversial.In order to better understand the mechanisms of hr-HPV-induced carcinogenesis, we have interested in: (i) the study of the biological functions of the E6*I isoform, and (ii) the mechanisms involved in the regulation of E6 and E7 expression.To get insight the biological role of HPV16 E6*I, we used RNA sequencing to identify targets deregulated by its ectopic expression. Expression of HPV16 E6 and E6*I isoforms in negative HPV cells deregulate several transcripts involved in biological processes related to viral gene expression, viral carcinogenesis, signal transduction and translation. The expression of E6*I alone, deregulates transcripts involved in the organization of the extracellular matrix, signaling pathways and cell adhesion. Interestingly, it was shown that the genes deregulated by E6*I expression are commonly affected by the intracellular level of ROS (reactive oxygen species). These results support the role of E6*I in increasing ROS production. The ROS-associated oxidative stress could favor viral genome integration with that of the host cell, a characteristic of hr-induced carcinogenesis. In sum, E6*I may have an oncogenic role independent of E6, and intervene in the carcinogenesis associated with hr-HPV.We also studied the role of the exon junction complex (EJC) in the posttranscriptional regulation of E6 and E7 expression. EJC is a multiprotein complex deposited on mRNAs via splicing, thus influencing their fate. We have shown that a factor of EJC, eukaryotic initiation factor 4A3 (eIF4A3), binds to viral mRNAs. Moreover, we have observed that the components of the EJC affected, in different ways, the expression of E6 and E7. Finally, we also studied the effect of nonsense-mediated mRNA decay (NMD), a mechanism linked to the EJC, on the expression of E6 and E7. Our results suggest that not only NMD inhibits the expression of E6 and E7, but we have also observed that HPV16 E6 protein reduces NMD activity. This inhibition would allow HPV16 to have control over its transcripts but also to affect NMD cellular targets. Given the involvement of NMD-regulated genes in the maintenance of cellular homeostasis and adaptation, it would be interesting to understand the role of this new E6 activity in carcinogenesis associated with HPV-HR.

Les papillomavirus humains (HPV) sont des petits virus non enveloppés à ADN double brin, qui infectent les épithéliums cutanés et muqueux. Très largement répandus dans la population humaine, les infections sont la plupart du temps asymptomatiques, tandis qu'une minorité provoquent des verrues cutanées, des condylomes acuminés et des carcinomes. Les cancers induits par HPV représentent 640 000 cas en 2012 dans le monde et sont localisés au niveau anogénital et au niveau des voies aérodigestives supérieures.La transformation des cellules est induite en particulier par la surexpression de deux oncoprotéines virales : E6 et E7, qui sont nécessaires à l'initiation, la promotion et la progression du phénotype cancéreux. Leur extinction provoque d'ailleurs la mort des cellules cancéreuses. E6 et E7 favorisent par exemple la dégradation de p53 et pRb, induisant ainsi une prolifération non contrôlée et accrue des cellules infectées. Mais les deux oncoprotéines virales interagissent aussi avec plus de 150 partenaires protéiques et dérégulent l'homéostasie cellulaire. Fait intéressant, E6 et E7 modulent l'expression de nombreuses protéines impliquées dans l'établissement des marques épigénétiques, impliquées dans la régulation de l'expression des gènes. D'ailleurs, la surexpression des oncoprotéines virales peut être liée à la méthylation de l'ADN d'une partie du génome viral.Puisque E6 et E7 détournent la machinerie épigénétique de la cellule, l'objectif du travail de thèse a été d'étudier les mécanismes moléculaires régulant l'expression des oncoprotéines lors du traitement des cellules de cancers du col par un agent déméthylant de l'ADN, le 5-aza-2'-déoxycytidine (5azadC).Dans des cellules issues de cancers du col de l'utérus, nous avons observé qu'un traitement déméthylant induisait une répression de la protéine E6 et une déstabilisation de ses transcrits, suggérant l'implication d'un miARN. Parmi les miARN ciblant les transcrits viraux, le miR-375 était le plus susceptible d'être impliqué dans la déstabilisation des transcrits car (i) la méthylation de son promoteur augmente avec la gravité des lésions du col de l'utérus, (ii) il cible les transcrits viraux au niveau de cinq régions différentes, et (iii) son expression est augmentée lors du traitement de cellules dérivées du cancer du col de l'utérus avec le 5azadC. Il s'est avéré que le miR-375 était effectivement impliqué dans la répression partielle des transcrits viraux lors du traitement. Les résultats de cette étude suggèrent par ailleurs qu'un autre mécanisme moléculaire pourrait être impliqué dans cette répression. C'est pourquoi, dans un deuxième temps, nous avons étudié l'implication possible d'un facteur de transcription, TBX2, dans la répression des transcrits viraux. Bien que le taux transcriptionnel de TBX2 soit augmenté lors du traitement des cellules avec des fortes concentrations de 5azadC, nos résultats suggèrent que la protéine n'est pas exprimée dans les cellules, même après traitement, et que TBX2 ne régule pas l'activité du promoteur viral intégré au génome cellulaire.Le traitement des cellules par l'agent déméthylant entraîne aussi une perte de viabilité en particulier des cellules Ca Ski. En effet, le 5azadC induit un blocage du cycle en G2/M dans ces cellules, une augmentation du pourcentage de cellules en Sub-G1 et un clivage de la PARP. Si le 5azadC est déjà utilisé en clinique pour le traitement d'autres cancers, nos données apportent un éclairage nouveau sur les mécanismes moléculaires du 5azadC dans les cancers induits par HPV, qui pourraient ainsi être traités par cette molécule. / Human papillomaviruses (HPV) are small, non-enveloped double-stranded DNA viruses and infect cutaneous and mucosal epithelia. Highly widespread in the human population, infections are mostly asymptomatic, while a minority causes cutaneous and genital warts, and carcinomas. HPV-induced cancers represent 640 000 cases in 2012 worldwide and are localized at the anogenital and head and neck sites.Cell transformation is induced by the overexpression of two viral oncoproteins E6 and E7, which are necessary for the initiation, promotion and progression of the cancerous phenotype. Indeed, their extinction causes cancer cell death. E6 and E7, for example, promote the degradation of p53 and pRb, thus inducing uncontrolled and increased proliferation of infected cells. But the two viral oncoproteins also interact with more than 150 protein partners and deregulate cell homeostasis. Interestingly, E6 and E7 modulate the expression of many proteins involved in the establishment of epigenetic marks, regulating gene expression. Furthermore, the overexpression of viral oncoproteins may be related to viral genome DNA methylation.Since E6 and E7 hijack epigenetic mechanisms, the aim of the thesis was to study the molecular mechanisms regulating the oncoprotein expression during the treatment of cervical cancer cells by a DNA demethylating agent, the 5-aza-2'-deoxycytidine (5azadC).In cervical cancer cells, we observed that a demethylating treatment induced E6 protein repression and destabilization of its transcripts, suggesting the involvement of a miRNA. Among miRNAs targeting viral transcripts, miR-375 was most likely to be involved this destabilization because (i) its promoter methylation increases with the severity of cervical lesions, (ii) it targets viral transcripts at five different regions, and (iii) its expression is increased in cervical cancer cells treated with 5azadC. In our experiences, miR-375 was indeed involved in the partial repression of viral transcripts during treatment. The results of this study further suggest that another molecular mechanism might be implicated in this repression. This is why, in a second step, we studied the possible involvement of a transcription factor, TBX2, in the viral transcript repression. Although the transcriptional rate of TBX2 is increased in cells treated with high concentrations of 5azadC, our results suggest that the protein is not expressed in cells, even after treatment, and that TBX2 does not regulate the viral promoter activity integrated into the cellular genome.Cell treatment with demethylating agent also leads to loss of viability, in particular in Ca Ski cells. Indeed, 5azadC induces a G2/M cycle arrest in these cells, an increase of Sub-G1 cells percentage and a PARP cleavage. While 5azadC is already used in clinical practice for the treatment of other cancers, our data shed new light on the molecular mechanisms of 5azadC in cancers induced by HPV, which could be treated by this molecule or analogues.