The papillomavirus E5 gene does not affect EGFR transcription and overall survival in cervical cancer.

INTRODUCTION: The human papillomavirus (HPV) E5 gene encodes a small and highly hydrophobic oncoprotein that affects immune evasion, cell proliferation, loss of apoptotic capacity and angiogenesis in tumors. E5 shows an affinity for biological membranes and was associated with an increase of epidermal growth factor/epidermal growth factor receptor (EGF/EGFR) signaling through the accumulation of EGFR in cellular membranes. Due to the frequent integration of the HPV genome into the host cell genome, E5 is frequently not transcribed in cervical tumors. AIM: In this study we looked forward to verifying whether the potential expression of E5 protein in human papillomavirus 16 positive (HPV16+ ) and human papillomavirus 18 positive (HPV18+ ) cervical tumors was associated with levels of EGFR and vascular endothelial growth factor A (VEGFA) transcription and with patients overall survival. RESULTS: Association between the presence of E5 transcripts and viral genome disruption was observed for HPV16+ and HPV18+ tumors. Association was not observed between tumors potentially capable of translating E5 and EGFR or VEGFA transcriptional levels. Similarly, the capability of translating E5 and overall survival in patients with HPV16+ squamous cell carcinoma tumors stage ≥ IB2 were not associated. CONCLUSION: The likely presence of E5 transcripts was neither associated to a higher activity of the EGFR-VEGFA pathway nor to the overall survival of patients with HPV16+ squamous cell carcinoma in stages ≥ IB2.

Methylation of p16 ink4a promoter is independent of human papillomavirus DNA physical state: a comparison between cervical pre-neoplastic and neoplastic samples

BACKGROUND Epigenetic modifications in host cells, like p16 ink4a methylation, have been considered as putative complementary mechanisms for cancer development. Because only a small proportion of infected women develop cervical cancer, other factors might be involved in carcinogenesis, either independently or in association with high-risk human papillomavirus (HR-HPV) infections, including epigenetic factors. OBJECTIVES We hypothesised that p16 ink4a methylation might have a role in cancer development driven by HPV16, mainly in the presence of intact E1/E2 genes. Thus, our objectives were to assess the status of p16 ink4a methylation and the HPV16 E1/E2 integrity in samples in different stages of cervical diseases. METHODS Presence of HPV16 was determined by E6 type-specific polymerase chain reaction (PCR). Methylation status of the p16 ink4a promoter was assessed by methylation-specific PCR in 87 cervical specimens comprising 29 low-grade (LSIL), 41 high-grade (HSIL) lesions, and 17 cervical cancers (CC). Characterisation of E1 and E2 disruption (as an indirect indicator of the presence of episomal viral DNA) was performed by PCR amplifications. FINDINGS We observed a significantly increased trend (nptrend = 0.0320) in the proportion of methylated p16 ink4a in cervical samples during cancer development. Concomitant E1 and E2 disruptions were the most frequent pattern found in all groups: CC (76%), HSIL (54%), and LSIL (73%). No statistically significant differences between p16 ink4a methylation and E1/E2 integrity, in histological groups, was observed. MAIN CONCLUSIONS There was an increase in methylation of the p16 ink4a promoter from pre-neoplastic lesions to cancer. Additionally, a high frequency of E1/E2 disruptions in LSIL/HSIL suggested that viral DNA integration was an early event in cervical disease. Moreover, the methylation status was apparently independent of HPV16 integrity.

Methylation of p16 ink4a promoter is independent of human papillomavirus DNA physical state: a comparison between cervical pre-neoplastic and neoplastic samples.

BACKGROUND Epigenetic modifications in host cells, like p16 ink4a methylation, have been considered as putative complementary mechanisms for cancer development. Because only a small proportion of infected women develop cervical cancer, other factors might be involved in carcinogenesis, either independently or in association with high-risk human papillomavirus (HR-HPV) infections, including epigenetic factors. OBJECTIVES We hypothesised that p16 ink4a methylation might have a role in cancer development driven by HPV16, mainly in the presence of intact E1/E2 genes. Thus, our objectives were to assess the status of p16 ink4a methylation and the HPV16 E1/E2 integrity in samples in different stages of cervical diseases. METHODS Presence of HPV16 was determined by E6 type-specific polymerase chain reaction (PCR). Methylation status of the p16 ink4a promoter was assessed by methylation-specific PCR in 87 cervical specimens comprising 29 low-grade (LSIL), 41 high-grade (HSIL) lesions, and 17 cervical cancers (CC). Characterisation of E1 and E2 disruption (as an indirect indicator of the presence of episomal viral DNA) was performed by PCR amplifications. FINDINGS We observed a significantly increased trend (nptrend = 0.0320) in the proportion of methylated p16 ink4a in cervical samples during cancer development. Concomitant E1 and E2 disruptions were the most frequent pattern found in all groups: CC (76%), HSIL (54%), and LSIL (73%). No statistically significant differences between p16 ink4a methylation and E1/E2 integrity, in histological groups, was observed. MAIN CONCLUSIONS There was an increase in methylation of the p16 ink4a promoter from pre-neoplastic lesions to cancer. Additionally, a high frequency of E1/E2 disruptions in LSIL/HSIL suggested that viral DNA integration was an early event in cervical disease. Moreover, the methylation status was apparently independent of HPV16 integrity.

HPV DNA methylation at the early promoter and E1/E2 integrity: A comparison between HPV16, HPV18 and HPV45 in cervical cancer.

OBJECTIVES: To compare and describe type-specific characteristics of HPV16, HPV18 and HPV45 in cervical cancer with respect to 3'LCR methylation and disruption of E1/E2. METHODS: The methylation level of 137 cervical cancer samples (70 with HPV16, 37 with HPV18, and 30 with HPV45) of Brazilian patients was analyzed by pyrosequencing. PCR amplifications were performed to characterize E1 and E2 disruption as an episomal surrogate. RESULTS: The 3'LCR of HPV16 showed a higher methylation at all CpG sites (7%, 9%, 11%, 10% and 10%) than homologous HPV18 regions (4%, 5%. 6%, 9% and 5%) and HPV45 regions (7%, 7% and 5%). Presence of intact E1/E2 was associated with higher HPV16 and HPV18 methylation levels at all CpG sites (p < 0.05). Disruption of E1/E2 was more frequently found in HPV45 (97%) and HPV18 (84%) than in HPV16 DNA (30%). HPV16 disruption was more frequently found in E1 (48%) unlike HPV18, where it was found in E2 (61%). Concomitant disruption of E1/E2 was most frequent in HPV45 (72%). CONCLUSIONS: The findings showed a higher methylation associated with intact E1/E2 for HPV16 and HPV18. The closely phylogenetic related HPV18 and HPV45 share a similar methylation level and the frequency of viral genome disruption.

Diversidade de metilação no DNA de HPV16 e HPV18 em carcinomas cervicais invasivos / Diversity of hpv16 and hpv18 dna methylation in invasive cervical carcinomas

A metilação de citosinas em sítios CpG é uma das principais modificações epigenéticas e está frequentemente associada à repressão transcricional. Apesar de estudos demonstrarem que o promotor dos oncogenes E6/E7 apresenta modulação através da metilação e que existe aumento progressivo nos níveis de metilação em sítios CpG específicos durante a progressão do câncer cervical, pouco se sabe sobre o papel da metilação na regulação da transcrição viral e como características clínicas e biológicas do carcinoma cervical invasivo podem influenciar a metilação. O objetivo principal do trabalho foi caracterizar, em amostras de tumores cervicais invasivos, a diversidade dos níveis de metilação em sítios CpG presentes na LCR, L2 e L1 de HPV16 e HPV18. Os objetivos específicos: (i) caracterizar os níveis de metilação em sítios CpG na LCR de HPV16 e HPV18 por pirosequenciamento; (ii) caracterizar os níveis de metilação em sítios CpG na LCR, L2 e L1 de HPV16 e HPV18 por NGS; (iii) associar os níveis de metilação às características clínicas e biológicas da doença; e (iv) caracterização dos haplótipos de metilação de HPV16 e HPV18. As amostras foram obtidas de pacientes atendidas no ambulatório do INCA e diagnosticadas com câncer cervical invasivo. Foram selecionadas 229 amostras, sendo 165 infectadas com HPV16 e 64 com HPV18. PCR combinando iniciadores para os genes E1/E2 dos HPVs 16 e 18 foi utilizada para avaliar o estado físico do DNA viral. Os níveis de metilação foram determinados por conversão por bissulfito sódio das amostras de DNA, seguido de amplificação da região de interesse, LCR, L2 e L1, e análise por pirosequencimamento ou NGS. Informações clínicas e biológicas da doença foram extraídas de questionários, banco de dados e estudos prévios. Foram observados maiores níveis de metilação em sítios CpG presentes em L2 e L1 de HPV16 e HPV18 quando comparados à LCR...

DNA methylation plays one of the most important epigenetic modifications and often leads to repression of transcription. Despite studies that show oncogene promoters of HPV16 (P97) being modulated by methylation and that methylation in specific CpG sites is related to severity of cervical neoplasia, it is still unclear how methylation contributes to the viral transcription and how clinical and biological factors related with HPV can affect the methylation pattern in invasive cervical cancer (ICC). The main goal was to characterize diversity of methylation level in CpG sites of LCR, L2 and L1 of HPV16 and HPV18 in invasive cervical cancer samples. Specific goals: (i) characterize level of methylation in CpG sites at LCR of HPV16 and HPV18 by pyrosequencing; (ii) characterize level of methylation in CpG sites at LCR, L2 and L1 of HPV16 and HPV18 by NGS; (iii) associate level of methylation with clinical and biological tumor characteristics; and (iv) characterize the methylation haplotype of HPV16 and HPV18. The 229 selected samples, being 165 with HPV16 and 64 with HPV18, were obtained from biopsies of patients attended at INCA ambulatory and diagnosed with invasive cervical cancer (ICC). Level of methylation was assessed by means of bisulfite treatment followed by PCR and pyrosequencing or NGS. PCR combining pairs of primers was performed to assess integrity of E1 and E2 genes for HPV16 and HPV18. CaSki and HeLa cell lines were used as methylation control. Patient and clinical information were obtained from questionnaires, database and previous studies. The methylation level was higher in L2 and L1 CpG sites of HPV16 and HPV18 DNA in comparison with LCR...

Correlation of MCM2 detection with stage and virology of cervical cancer.

UNLABELLED: The highly conserved mini-chromosome maintenance proteins (MCM) are important in the initiation of DNA replication. Few studies have correlated MCM expression with the progression of cancer. OBJECTIVES: (i) To analyze the expression of MCM2 in cervical cancer; (ii) to correlate MCM2 expression with the clinical tumor staging according to FIGO classification, and (iii) to relate HPV type to MCM2 expression. METHODS: Tissue micro-arrays (TMA) from patients with invasive cervical cancer and controls were analyzed. Human papillomavirus (HPV) DNA detection and HPV types were determined by in situ hybridization, PCR, and sequencing. MCM2 expression was analyzed by immunohistochemistry. RESULTS: The most prevalent HPV types found in invasive cancer were HPV 16 (66.6%), followed by HPV 33 (11.8%), and HPV 35 (3.6%). An increased (p<0.05) expression of MCM2 was found in invasive cervical cancers compared to controls. Moreover, a strong correlation was found between the MCM2-positive cells and the presence of HPV DNA detected by in situ hybridization. No statistically significant difference was observed between MCM2 expression and FIGO stage. CONCLUSIONS: The present study shows that HPV-infected cells strongly express MCM2; nevertheless, our data suggests that MCM2 is not a good biomarker when comparing the different clinical stages of cervical cancer.

Análise comparativa de biomarcadores no câncer cervical invasivo e sua correlação com o tipo de HPV / Comparative analysis of biomarkers in invasive cervical cancer and its correlation with hpv type

O câncer cervical é o terceiro tipo de câncer mais comum entre mulheres no mundo. Dentre outros cofatores, a infecção pelo HPV de alto risco, tem sido bem documentada como fator necessário ao desenvolvimento desse tipo de câncer. A principal ação do HPV envolve a expressão massiva das oncoproteínas virais E6 e E7 que podem formar complexos específicos com proteínas supressoras de tumor, sendo capazes de alterar mecanismos do ciclo celular, modificando a expressão de proteínas celulares. Um dos principais avanços na medicina clínico patológica é o uso dessas proteínas como marcadores de forma a aumentar a acurácia do prognóstico e do próprio estadiamento do câncer cervical. Assim, a fim de reforçar a hipótese de que as proteínas associadas ao ciclo celular Ki-67, MCM-2, p53 e p16INK4a se encontram superexpressas no câncer cervical, foram analisadas em 87 amostras cervicais de pacientes com câncer invasivo (CCI) e 43 cérvix normais. Verificamos também se há uma expressão diferencial que pode ajudar a avaliação do estadiamento clínico da FIGO e quais tipos virais podem induzir a uma expressão diferencial dessas proteínas. Além disso, características sociodemográficas, comportamentais e clínicas das pacientes foram obtidas dos prontuários e analisadas. Para isso, a detecção de DNA de HPV foi realizada pela técnica da PCR e hibridização in situ. A expressão das proteínas foi observada por imunohistoquímica, seguida por quantificação manual e através do software ImagePro Plus. A análise estatística foi feita utilizando o software STATA/SE 10.1 aplicando os testes: Kruskall-Wallis, Student, Fisher e Qui-Quadrado. Nossos resultados mostraram forte associação (p<0,05) do CCI e dos estágios tumorais mais avançados (III e IV) com mulheres superiores a 55 anos, com mais de quatro gestações e sem escolaridade. A prevalência de DNA de HPV por PCR na população total foi de 73,4 por cento. Nos grupos de CCI e controle foram, respectivamente, 94,3 por cento e 29,3 por cento. O tipo mais prevalente foi o HPV16 (70,8 por cento), acompanhado pelo HPV33 (11,2 por cento) e 35 (4,5 por cento). Como esperado, foi observado aumento (p<0,05) na expressão de Ki-67, MCM-2, p53 e p16INK4a no CCI, quando comparados ao controle. A proteína p16INK4a com expressão difusa, citoplasmática e nuclear esteve associada ao câncer. Ki-67 apresentou forte expressão (>50 por cento) conforme o agravamento da doença. Não foi observada associação entre a expressão de MCM-2, p53 e p16, e o estadiamento do tumor. Como conclusões, foram observadas maiores chances no desenvolvimento do CCI em mulheres com idades superiores a 55 anos, com mais de quatro gestações e sem escolaridades, estando esses fatores associados, também, à progressão tumoral. Apenas o marcador Ki-67 associouse ao estágio do CCI. Os tipos mais prevalentes encontrados, HPV16, 33, 35, 67 e 58, sugerem que novos estudos devam ser considerados para implementação de vacinação contra o HPV no Brasil.