Immunology of cervical cancer

ABSTRACT Optimal function of the immune system allows the recognition and elimination of infected and tumor cells. However, these cells can develop mechanisms to evade the cellular immune response. In human papillomavirus (HPV) infection, dysregulation of major histocompatibility complex Class I molecules and other components of the innate immune system promote the survival of infected cells by allowing the infection to persist which, in turn, favors the development of cancer. Further, tumor cells possess inherent mechanisms designed to block the recognition and activation of cytotoxic lymphocytes: particularly, HPV proteins such as E1 and E2 and oncoproteins E5, E6, and E7 that inhibit immune mechanisms and/or stimulate the expression of immunosuppressive cytokines. These mechanisms include a decrease in receptor activation and costimulating molecules on the surface of immune cells, as well as the constitutive expression of molecules that inhibit their function, which allow HPV persistence and tumor progression. Immunotherapy-based therapeutic options are positioned as excellent candidates for the treatment of cervical cancer.

Human papillomavirus type 18 E5 oncoprotein cooperates with E6 and E7 in promoting cell viability and invasion and in modulating the cellular redox state

BACKGROUND High-risk human papillomaviruses (HR-HPVs) are the etiological agents of cervical cancer. Among them, types 16 and 18 are the most prevalent worldwide. The HPV genome encodes three oncoproteins (E5, E6, and E7) that possess a high transformation potential in culture cells when transduced simultaneously. In the present study, we analysed how these oncoproteins cooperate to boost key cancer cell features such as uncontrolled cell proliferation, invasion potential, and cellular redox state imbalance. Oxidative stress is known to contribute to the carcinogenic process, as reactive oxygen species (ROS) constitute a potentially harmful by-product of many cellular reactions, and an efficient clearance mechanism is therefore required. Cells infected with HR-HPVs can adapt to oxidative stress conditions by upregulating the formation of endogenous antioxidants such as catalase, glutathione (GSH), and peroxiredoxin (PRX). OBJECTIVES The primary aim of this work was to study how these oncoproteins cooperate to promote the development of certain cancer cell features such as uncontrolled cell proliferation, invasion potential, and oxidative stress that are known to aid in the carcinogenic process. METHODS To perform this study, we generated three different HaCaT cell lines using retroviral transduction that stably expressed combinations of HPV-18 oncogenes that included HaCaT E5-18, HaCaT E6/E7-18, and HaCaT E5/E6/E7-18. FINDINGS Our results revealed a statistically significant increment in cell viability as measured by MTT assay, cell proliferation, and invasion assays in the cell line containing the three viral oncogenes. Additionally, we observed that cells expressing HPV-18 E5/E6/E7 exhibited a decrease in catalase activity and a significant augmentation of GSH and PRX1 levels relative to those of E5, E6/E7, and HaCaT cells. MAIN CONCLUSIONS This study demonstrates for the first time that HPV-18 E5, E6, and E7 oncoproteins can cooperate to enhance malignant transformation.

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.

Association between the p53 arginine/arginine homozygous genotype at codon 72 and human papillomavirus E6/E7 mRNA expression

ABSTRACT Objective: To evaluate the association between p53 polymorphisms and human papillomavirus (HPV) E6/E7 mRNA expression. Methods: We analyzed 175 cervical samples from women aged 16-69 years old who were tested for HPV E6/E7 mRNA expression (NucliSENS® EasyQ® HPV). The samples were divided into three groups: positive (n = 75) those with positive HPV E6/E7 mRNA expression and positive high-risk HPV Hybrid Capture (HR-HC) test; negative (n = 52) those with negative HPV E6/E7 mRNA expression and positive HR-HC; and control (n = 48) those with negative HPV E6/E7 mRNA expression and negative HR-HC. The p53 polymorphisms at codons 11, 72, and 248 were evaluated through polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results: The frequency of the arginine/arginine homozygous genotype at codon 72 was significantly higher in the positive (49.3%) than in the negative (32.7%) and control groups (20.8%, p = 0.002*). The frequency of the arginine allele was also significantly higher in the positive (67.3%) than in the negative (53.8%) and control groups (38.5%, p < 0.001*). The arginine/arginine homozygous genotype was significantly associated with positive HPV E6/E7 mRNA expression (positive group) compared with negative and control groups (odds ratio: 2.633; 95% CI, 1.399-4.954, p = 0.003). The frequency of arginine/arginine homozygous genotype at codon 72 remained significantly more frequent in the positive group of women aged ≥30 years than in the other two groups. Conclusion: The presence of the p53 arginine/arginine homozygous genotype at codon 72 was significantly associated with the positive HPV E6/E7 mRNA expression.

High Risk HPV E6/E7 Oncoprotein Expression in Women with High Grade Squamous Intraepithelial Lesion / Expressão de oncoproteinas E6/e7 do HPV de alto risco em Mulheres com Lesão Intraepitelial Escamosa de alto grau

Purpose To correlate the expression of high-risk HPV E6 mRNA with pap smear, colposcopy, and biopsy results in women with high grade squamous intraepithelial lesion (HSIL). Methods A cross-sectional study was performed on women referred for primary care services after cytological diagnosis of HSIL. We evaluated the expression of E6/E7 mRNA of HPV types 16,18,31,33, and 45 and correlated the results with those of Pap smear, colposcopy, and biopsy. For amplification/detection of mRNA E6 / E7 we used NucliSENSEasyQ kit to detect HPV mRNA by polymerase chain reaction with primers/ probes for HPV types 16, 18, 31, 33, and 45. Results Out of 128 valid tests, the results of 30 (23.4%) tests were negative and 98 (70%) tests were positive. Only one type of HPV was detected in 87.7% of the E6/E7 mRNA positive cases. HPV16 was detected in 61.2% of the cases, followed by HPV33 (26.5%), HPV31 (17.3%), HPV18 (10%), and HPV45 (4.08%). Pap smear tests revealed that the E6/E7 test was positive in 107 (83.8%) women with atypical squamous cells - high grade (ASC-H), HSIL, or higher. The E6/E7 test was positive in 69 (57.5%) specimens presenting negative cytology results. When analyzing the association with colposcopy results, the frequency of positive E6/E7 results increased with the severity of the injury, ranging from 57.1% in women without colposcopy-detected injury to 86.5% in those with higher levels of colposcopy findings. Of the 111 women who underwent biopsy and E6/E7 testing, the E6/E7 test was positive in 84.7% of the women who presented with lesions of cervical intraepithelial neoplasia (CIN) grade 2 or higher. Finally, 41.2% of women with a negative biopsy presented a positive E6/E7 test. Conclusions E6/E7mRNA expression was higher in women with HSIL and CIN grade 2 or higher.

Objetivo Correlacionar a expressão mRNAE6/E7 do HPV de alto risco com os exames de Papanicolau, colposcopia e biópsia em mulheres com lesão intraepitelial escamosa de alto grau (HSIL). Métodos Estudo transversal com mulheres encaminhadas aos serviços de atenção primária com diagnóstico citológico de HSIL. Foi avaliada a expressão do mRNAE6/E7 dos tipos de HPV 16,18,31,33 e 45, correlacionando-se a expressão com os exames de Papanicolau, colposcopia e biópsia. Para a amplificação/detecção demRNA de E6/E7 foi usado o kit NucliSENS EasyQ(r) HPV que detecta mRNA do HPV por meio da reação em cadeia da polimerase com primers/probes HPV dos tipos 16, 18, 31, 33 e 45. Resultados Foram obtidos 128 testes válidos. Destes: 30 (23,4%) foram negativos e 98 (70%) dos testes foram positivos. Foi encontrado apenas um tipo de HPV em 87,7% dos positivos. O HPV16 foi omais encontrado em61,2%, seguido pelos HPV33 (26,5%); HPV31 (17,34%); HPV 18 (10,0%) e HPV (45 4,0%). Quanto ao exame de Papanicolau, o teste E6/E7 foi positivo em 107 (83,8%) das mulheres com ASC-H, HSIL ou superior, enquanto em citologia negativa foi encontrado um resultado positivo em 69 (57,5%) colposcopia. A frequência de teste E6/E7 positivo aumentou com a gravidade da lesão, detectada na colposcopia variando de 57,1% em mulheres sem lesão identificada em colposcopia até 86,5% naqueles com achado de colposcopia de grau maior. Das 111 mulheres que se submeteram a biópsia e o teste E6/E7, o teste foi positivo em 84,7% das que apresentaramlesão igual ou superior a NIC 2 (neoplasia intraepitelial cervical) e 41,2% daqueles com biópsia negativa. Conclusões A expressão de E6, E7 RNAm ocorreu commaior frequência emlesões de alto grau citológica e em casos com biópsias de NIC2 ou maior.

Clinical Alarms in intensive care: implications of alarm fatigue for the safety of patients / Alarmes clínicos em terapia intensiva: implicações da fadiga de alarmes para a segurança do paciente / Alarmas clínicas en terapia intensiva: implicaciones de la fatiga de alarmas para la seguridad del paciente

OBJECTIVES: to identify the number of electro-medical pieces of equipment in a coronary care unit, characterize their types, and analyze implications for the safety of patients from the perspective of alarm fatigue. METHOD: this quantitative, observational, descriptive, non-participatory study was conducted in a coronary care unit of a cardiology hospital with 170 beds. RESULTS: a total of 426 alarms were recorded in 40 hours of observation: 227 were triggered by multi-parametric monitors and 199 were triggered by other equipment (infusion pumps, dialysis pumps, mechanical ventilators, and intra-aortic balloons); that is an average of 10.6 alarms per hour. CONCLUSION: the results reinforce the importance of properly configuring physiological variables, the volume and parameters of alarms of multi-parametric monitors within the routine of intensive care units. The alarms of equipment intended to protect patients have increased noise within the unit, the level of distraction and interruptions in the workflow, leading to a false sense of security. .

OBJETIVOS: identificar o número de alarmes dos equipamentos eletromédicos numa unidade coronariana, caracterizar o tipo e analisar as implicações para a segurança do paciente na perspectiva da fadiga de alarmes. MÉTODO: trata-se de estudo quantitativo observacional descritivo, não participante, desenvolvido numa unidade coronariana de um hospital de cardiologia, com capacidade para 170 leitos. RESULTADOS: registrou-se o total de 426 sinais de alarmes, sendo 227 disparados por monitores multiparamétricos e 199 alarmes disparados por outros equipamentos (bombas infusoras, hemodiálise, ventiladores mecânicos e balão intra-aórtico), nas 40h, numa média total de 10,6 alarmes/hora. CONCLUSÃO: os resultados encontrados reforçam a importância da configuração de variáveis fisiológicas, do volume e dos parâmetros de alarmes dos monitores multiparamétricos à rotina das unidades de terapia intensiva. Os alarmes dos equipamentos destinados a proteger os pacientes têm conduzido ao aumento do ruído na unidade, à fadiga de alarmes, a distrações e interrupções no fluxo de trabalho e à falsa sensação de segurança. .

OBJETIVOS: identificar el número de alarmas de los equipamientos electromédicos en una unidad coronariana, caracterizar el tipo y analizar las implicaciones para la seguridad del paciente en la perspectiva de fatiga de alarmas. MÉTODO: se trata de un estudio cuantitativo, observacional, descriptivo, no participante, desarrollado en una unidad coronariana de un hospital de cardiología, con capacidad de 170 camas. RESULTADOS: se registró un total de 426 señales de alarmas, siendo 227 disparadas por monitores multiparamétricos y 199 disparadas por otros equipamientos (bombas de infusión, hemodiálisis, ventiladores mecánicos y balón intraaórtico), durante 40h, con un promedio total de 10,6 alarmas/hora. CONCLUSIÓN: los resultados encontrados refuerzan la importancia de la configuración de las variables fisiológicas, del volumen y de los parámetros de alarma de los monitores multiparamétricos, a la rutina de las unidades de terapia intensiva. Las alarmas de los equipamientos destinados a proteger a los pacientes, han llevado al aumento del ruido en la unidad, a la fatiga de alarmas, a las distracciones e interrupciones en el flujo de trabajo y a una falsa sensación de seguridad. .

Papel das proteínas precoces do papilomavírus humano na carcinogênese / Role of the Human Papillomavirus Early Proteins in the Carcinogenesis

Introdução: O Papilomavírus Humano (HPV) é um agente epiteliotrópico que apresenta mais de 100 genótipos.Destes, alguns são considerados de alto risco devido ao potencial para induzir o surgimento de lesões malignas, comoo carcinoma cervical, cujo percentual de associação com o referido vírus é de aproximadamente 90%. Nas célulasinfectadas, duas proteínas virais desempenham papel fundamental na tumorigênese. Objetivo: Realizar uma revisão dos trabalhos existentes na literatura científica internacional com enfoque no papel das proteínas virais do HPV na carcinogênese. Método: Os artigos utilizados para a realização da presente revisão foram selecionados e obtidos na íntegra nos portais eletrônicos Pubmed e Periódicos Capes. Os descritores utilizados na busca incluíram: Human Papillomavirus, HPV, viral proteins, E5, E6 e E7. Resultados: As proteínas virais E6 e E7 são amplamente conhecidas por promoverem a degradação das proteínas celulares p53 e pRb, respectivamente, efeito que responde por grande parte do potencial oncogênico dos genótipos de alto risco de HPV, sendo funcionalmente equivalentes a mutações dos referidos genes celulares, que são comumente observadas em diversos tumores. Contudo, novos estudos têm demonstrado que essas proteínas virais também estão envolvidas em diversas outras vias tumorais, denotando novamente a relevância das mesmas nesse processo. Ademais, alguns trabalhos apontam a proteína E5 como coadjuvante na carcinogênese. Conclusão: Os diversos efeitos constatados das proteínas precoces virais culminam no favorecimentoda proliferação celular descontrolada, imortalização, regulação da diferenciação celular, suscetibilidade à metástase e escape da vigilância imunológica

Ciclo celular, HPV e evolução da neoplasia intraepitelial cervical: seleção de marcadores biológicos / Cell cycle, HPV and cervical intraepithelial neoplasia evolution: biomarkers selection

O câncer de colo do útero é a segunda causa de câncer mais comum entre as mulheres em todo o mundo, sendo precedido por lesões precursoras denominadas neoplasias intraepiteliais cervicais (NICs), de grau 1, 2 e 3. A relação entre o papilomavírus humano (HPV) e o câncer de colo uterino já está bem estabelecida. O ciclo de vida do HPV, assim como seu mecanismo de ação sobre o ciclo celular da célula hospedeira, causam a transformação neoplásica e progressão das lesões precursoras para o câncer de colo uterino. Tal transformação está associada principalmente à expressão de dois genes do HPV: o E6 e o E7, cujos produtos interferem no controle do ciclo celular, tendo como alvos principais as proteínas p53 e pRB. Esta revisão de literatura pretende fornecer ao leitor conhecimento da ação do HPV sobre o ciclo celular, visando identificar potenciais marcadores biológicos da evolução das lesões precursoras ao câncer de colo uterino.

Cervical cancer is the second most common malignant disease in women worldwide and is preceded by cervical intraepithelial neoplasia (CIN) grades 1, 2 and 3. The relationship between human papillomavirus (HPV), cervical CIN and cervical cancer is well established. The HPV life cycle cause neoplastic transformation and CIN progression for cervical cancer. This transformation is associated with E6 and E7 HPV genes, whose products interfere with cell cycle control, mainly through action on p53 and pRB proteins. This review aims to provide to the reader an update for the understanding of the HPV effects on the cell cycle, attempting to identify potential biological markers for the evolution of precursor lesions to cervical cancer.

Cáncer cérvicouterino y virus del papiloma humano / Cervical cancer and human papillomavirus

El cáncer cérvicouterino (CaCu) es la segunda causa de muerte por cáncer en mujeres de todo el mundo, a pesar de la implementación de la citología de cérvix para su prevención. Esto se debe a la baja sensibilidad y especificidad de la prueba, lo cual apoya a un cambio urgente en la forma de tamizaje para su detección. Ahora se sabe que la infección persistente por virus del papiloma humano de alto riesgo (HR-HPV) es la causa de la totalidad de los casos de CaCu. En la actualidad se están utilizando vacunas frente a dos (Bivalente: HPV-16 y HPV-18) o cuatro (Tetravalente: HPV-6 HPV-11, HPV-16 y HPV-18) de las cepas de HR-HPV que causan la mayoría de los casos de CaCu. El propósito de este artículo es proporcionar una revisión de las características principales del virus y de los mecanismos que se echan a andar bajo la infección persistente de las células cervicales, lo cual conduce a la proliferación desordenada y a la malignización de las células infectadas. Es necesario que el virus se integre al genoma de la célula epitelial para que inicie la expresión de las oncoproteínas virales E6 y E7 lo cual conducirá al desarrollo del CaCu.

Cervical cancer (CC) is the second cause of death for cancer in women worldwide in spite of the implementation of cervix cytology screenings for its prevention. The low sensibility and specificity of the test reduce the potential benefits of these screenings and supports urgent improvements in early detection tests for CC. It is now known that persistent infection with the high-risk human papiloma virus (HR-HPV) is the causal agent of almost all cases of CC. HR-HPV vaccines effective against two (Bivalent: HPV-16 and HPV-18) or four (Tetravalent: HPV-6 HPV-11, HPV-16 and HPV-18) strains that are responsible of the majority of the CC cases have been licensed in several countries. The present study aims to provide a review of the principal characteristics of the HR-HPV virus and of the mechanisms that take to the persistent infection of the cervical cells leading to abnormal proliferation and malignancy. It is necessary that the virus integrates into the genome of the epithelial cell to initiates the expression of the E6 and E7 viral oncoproteins which will lead to the development of the CC.

Production of L1 protein from different types of HPV in Pichia pastoris using an integrative vector

Human papillomavirus (HPV) infection is the most common sexually transmitted disease in the world and is related to the etiology of cervical cancer. The most common high-risk HPV types are 16 and 18; however, the second most prevalent type in the Midwestern region of Brazil is HPV-33. New vaccine strategies against HPV have shown that virus-like particles (VLP) of the major capsid protein (L1) induce efficient production of antibodies, which confer protection against the same viral type. The methylotrophic yeast Pichia pastoris is an efficient and inexpensive expression system for the production of high levels of heterologous proteins stably using a wild-type gene in combination with an integrative vector. It was recently demonstrated that P. pastoris can produce the HPV-16 L1 protein by using an episomal vector associated with the optimized L1 gene. However, the use of an episomal vector is not appropriate for protein production on an industrial scale. In the present study, the vectors were integrated into the Pichia genome and the results were positive for L1 gene transcription and protein production, both intracellularly and in the extracellular environment. Despite the great potential for expression by the P. pastoris system, our results suggest a low yield of L1 recombinant protein, which, however, does not make this system unworkable. The achievement of stable clones containing the expression cassettes integrated in the genome may permit optimizations that could enable the establishment of a platform for the production of VLP-based vaccines.

Comparative analysis of three methods for HPV DNA detection in cervical samples / Análisis comparativo de tres métodos para la detección del ADN de VPH en muestras de cuello uterino

High risk HPV infection is considered to play a central role in cervical carcinogenesis. HPV DNA testing has shown to be a very useful tool for screening and following cervical infections. The aim of this study was to compare three methods for HPV DNA detection, along with cytology and colposcopy analysis. Cervical samples were collected from 100 sexually active women in Mérida, western Venezuela. HPV infection was screened using Hybrid-Capture 2 (HC2), L1-Nested-PCR and E6/E7-PCR assays. 40% of the samples (40/100) were HPV positive by at least one of the DNA detection methods. HC2 detected HPV in 12% specimens. L1- and E6/E7-PCRs showed 50% sensitivity and 77% specificity.The agreement rate between HC2 and both PCR assays was 65%. Kappa value showed moderate concordance between HC2 and both PCR methods (κ=0.55; CI 95%). Also moderate concordance was seen when L1- and E6/E7-PCRs were compared (κ=0.48; CI 95%). There was a significant association between the Schiller test and E6/E7-PCR (p=0.006) for HPV infection. An acceptable agreement between all three assays for HPV detection was observed. Nevertheless, different PCR formats need to be further analyzed in order to make the right choice of method for HPV testing.

La infección con VPH de alto riesgo es el principal factor etiológico asociado al desarrollo de carcinogénesis cervical y las pruebas de detección de ADN-VPH han mostrado ser una herramienta esencial para la pesquisa y seguimiento de estas infecciones. El objetivo del estudio ha sido comparar tres métodos para la detección del ADN viral, en combinación con los análisis colposcópico y citológico. Se obtuvieron muestras cervicales de 100 mujeres sexualmente activas, en Mérida, Venezuela. La detección de infecciones por VPH se realizó por Captura Híbrida 2 (CH2) y los ensayos de PCR “L1-Nested-PCR” y “E6/E7-PCR”. 40% de las muestras (40/100) fueron positivas para VPH por al menos uno de los métodos aplicados. 12% de las muestras analizadas fueron positivas para VPH por CH2. Las dos PCR utilizadas mostraron un 50% de sensibilidad y 77% de especificidad. La coincidencia observada entre CH2 y las dos PCR fue del 65%. La determinación del valor Kappa mostró una concordancia moderada entre CH2 y ambos métodos de PCR (κ=0,55; CI 95%). También existió concordancia moderada al comparar las PCR de las regiones L1 y E6/E7 de VPH (κ=0,48; CI 95%). Hubo una asociación significativa entre el resultado del test de Schiller y la PCR E6/E7 (p=0,006) para la infección por VPH. Se determinó una concordancia aceptable entre los tres métodos aplicados para la detección de VPH; sin embargo, las PCR deben ser analizadas en trabajos futuros con el fin de establecer las pruebas más adecuadas para la detección viral.

Enhanced anti-tumor effect of a gene gun-delivered DNA vaccine encoding the human papillomavirus type 16 oncoproteins genetically fused to the herpes simplex virus glycoprotein D

Anti-cancer DNA vaccines have attracted growing interest as a simple and non-invasive method for both the treatment and prevention of tumors induced by human papillomaviruses. Nonetheless, the low immunogenicity of parenterally administered vaccines, particularly regarding the activation of cytotoxic CD8+ T cell responses, suggests that further improvements in both vaccine composition and administration routes are still required. In the present study, we report the immune responses and anti-tumor effects of a DNA vaccine (pgD-E7E6E5) expressing three proteins (E7, E6, and E5) of the human papillomavirus type 16 genetically fused to the glycoprotein D of the human herpes simplex virus type 1, which was administered to mice by the intradermal (id) route using a gene gun. A single id dose of pgD-E7E6E5 (2 µg/dose) induced a strong activation of E7-specific interferon-γ (INF-γ)-producing CD8+ T cells and full prophylactic anti-tumor effects in the vaccinated mice. Three vaccine doses inhibited tumor growth in 70 percent of the mice with established tumors. In addition, a single vaccine dose consisting of the co-administration of pgD-E7E6E5 and the vector encoding interleukin-12 or granulocyte-macrophage colony-stimulating factor further enhanced the therapeutic anti-tumor effects and conferred protection to 60 and 50 percent of the vaccinated mice, respectively. In conclusion, id administration of pgD-E7E6E5 significantly enhanced the immunogenicity and anti-tumor effects of the DNA vaccine, representing a promising administration route for future clinical trials.

Assessing protein stability of the dimeric DNA-binding domain of E2 human papillomavirus 18 with molecular dynamics

The objective of this study is to understand the structural flexibility and curvature of the E2 protein of human papillomavirus type 18 using molecular dynamics (6 ns). E2 is required for viral DNA replication and its disruption could be an anti-viral strategy. E2 is a dimer, with each monomer folding into a stable open-faced â-sandwich. We calculated the mobility of the E2 dimer and found that it was asymmetric. These different mobilities of E2 monomers suggest that drugs or vaccines could be targeted to the interface between the two monomers.

High prevalence and low E6 genetic variability of human papillomavirus 58 in women with cervical cancer and precursor lesions in Southeast Mexico

Infection with some genotypes of human papillomavirus (HPV) is the most important risk factor associated with cervical cancer (CC). Throughout the world, HPV type 58 prevalence varies from one region to another; it is higher in women from certain countries in Asia and Latin America, such as China and Mexico. Although intratypic variants have been reported on a few occasions, our knowledge about HPV 58 genetic variation remains limited. Therefore, this work aims to (i) determine the prevalence of HPV type 58 amongst Mexican women with invasive CC or precursor lesions and (ii) identify HPV 58 sequence variants. One hundred and forty five colposcopy clinic patients were studied. Genotyping of HPV 16, 18 and 58 was determined by specific nested PCR and HPV 58 variants were detected by direct sequencing. The general prevalence of HPV was 51.7 percent (75/145). HPV 16 was found in 30.6 percent (23/75) and HPV 58 in 24 percent (18/75) of the patients. HPV 18 was not identified in patients with cervical intraepithelial neoplasia (CIN) grade I; it was only found in those with CIN II, with a prevalence of 6.8 percent (3/44). In patients with CC, the prevalence of HPV 16 and 58 was 78.9 percent. Regarding HPV 58 variants, 94.4 percent of the HPV 58 sequences were identical to the prototype strain, whereas one sample showed changes at a single nucleotide. This study demonstrates a high prevalence of HPV 58 and a low genetic variability of E6 sequences amongst Mexican colposcopy patients.

Epidemiological and functional implications of molecular variants of human papillomavirus

Human papillomavirus genomes are classified into molecular variants when they present more than 98 percent of similarity to the prototype sequence within the L1 gene. Comparative nucleotide sequence analyses of these viruses have elucidated some features of their phylogenetic relationship. In addition, human papillomavirus intratype variability has also been used as an important tool in epidemiological studies of viral transmission, persistence and progression to clinically relevant cervical lesions. Until the present, little has been published concerning the functional significance of molecular variants. It has been shown that nucleotide variability within the long control region leads to differences in the binding affinity of some cellular transcriptional factors and to the enhancement of the expression of E6 and E7 oncogenes. Furthermore, in vivo and in vitro studies revealed differences in E6 and E7 biochemical and biological properties among molecular variants. Nevertheless, further correlation with additional functional information is needed to evaluate the significance of genome intratypic variability. These results are also important for the development of vaccines and to determine the extent to which immunization with L1 virus-like particles of one variant could induce antibodies that cross-neutralize other variants.

L1 sequence of a new human papillomavirus type-58 variant associated with cervical intraepithelial neoplasia

The present study on molecular characterization of a human papillomavirus (HPV) isolated in Central Brazil describes the L1 gene sequence from a new variant of HPV-58, the isolate Bsb-02. The sample was from a smear obtained from a woman with cervical intraepithelial neoplasia grade II. The whole L1 gene from isolate Bsb-02 was sequenced automatically, showing 99.1 percent nucleotide identity with the gene from the HPV-58 reference. The clustering between Bsb-02 and HPV-58 reference sequence was also supported by phylogenetic analysis. Fourteen nucleotide substitutions were observed: eight were synonymous and six were associated with amino acid substitutions. A10V and V144I have not been previously described. At GenBank, the only complete L1 sequence from HPV-58 in addition to the HPV-58 reference one is that of Bsb-02. These data provide information that may be relevant to HPV diagnosis and to rational vaccine strategies. HPV variants may also be associated with host immune responses and with the risk of cervical neoplasia.

Contribución de la vía P13k/Akt-PTEN y sus blancos corriente abajo en iniciación y progresión de glioblastoma multiforme / Contribution of the pi3k/akt-pten pathway and its downstream targets to the initiation and progression of multiform glioblastoma

Los tumores del sistema nervioso central constituyen un problema importante en oncología debido a que son de dificíl tratamiento y tienen un alto porcentaje de resistencia a la terapia, además de que su prónostico es muy pobre. El análisis de los cambios genéticos y moleculares asociados a la inicación y progresión del proceso tumoral constitutye una herraamienta importante para establecer grupos de tratamiento específico,para reducir la incidencia de resistencia al mismo para establecer nuevos blancos terapéuticos.Este artículo busca analizar diversos aspectos genéticos y moleculares subyacentes a la iniciación y progresión del tumor maligno más frecuente, el glioblastoma multiforme, procesos que siguen siendo poco conocidos. El análisis se centrará en la vía de supervivencia neuronal medida por los receptores tirosina quinasa (RTK) y sus blancos corriente abajo:PTEN,P13K, Akt, mTOR y hexoquinasa. Poco se sabe, sin embargo, acerca de cómo cambios genéticos y ,oleculares en estas vías de señalización celular se interrelacionan temporal y funcionalmente para determianr la progresión maligna y la resistencia a la terapia en glioblastoma multiforme. En la actualidad se está desarrollando un estudio in vivo e in vitro utilizando especímenes quirúrgicos y líneas celulares de glioblastoma, para analizar sus cambios genéticos y moleculares asociados a la vía P13K/Akt-PTEN, y realizar una correlación con la expresión de hexoquinasa, mTOR y telomerasa, y su importancia en cuanto a resistencia a la terapia.

Asociación entre la presencia de anticuerpos anti-Ras y anti-VPH16 E4/E7 y lesiones intraepiteliales del cérvix / Association between anti-Ras and anti-HPV16 E4/E7 antibodies with cervical intraepithelial lesions

OBJETIVO: Determinar si anticuerpos séricos contra E4, E7 y Ras pueden ser utilizados como marcadores de lesiones tempranas del cérvix uterino asociadas al virus del papiloma humano. MATERIAL Y MÉTODOS: Entre marzo de 1999 y abril de 2000 se realizó un estudio sero-epidemiológico de casos y controles en la clínica de displasias del Hospital General Doctor Gea González, en la Ciudad de México, en 116 muestras de suero para evaluar la presencia de anticuerpos anti-E4, E7 y Ras utilizando un ELISA de captura. Se estimaron razones de momios e intervalos de confianza de 95 por ciento RESULTADOS: Anticuerpos anti-E7 se asociaron a mujeres con lesiones NIC III, mientras que anticuerpos anti-E4 y anti-Ras fueron más frecuentes en lesiones NIC I-II. Al evaluar el perfil de anticuerpos que presentaron las mujeres, encontramos que a) anticuerpos contra dos proteínas predicen la existencia de una lesión NIC I-II, y b) la presencia de tres anticuerpos predicen una lesión NIC III. CONCLUSIONES: La detección de anticuerpos séricos contra E4, E7 y Ras en combinación con otras técnicas de diagnóstico, podrían ser de utilidad para detectar oportunamente a mujeres con lesiones tempranas asociadas al Virus del Papiloma Humano y en riesgo de desarrollar cáncer

HPV 16 detection in cervical lesions, physical state of viral DNA and changes in p53 gene

CONTEXT: Persistent infection with high risk human papillomavirus (HPV) has been linked to cervical carcinoma. Integration of viral DNA into host cell DNA is essential for this cancer development, promoting disruption of the HPV E2 gene, thus leading to unregulated increases in E6 and E7 proteins and inactivating the products of p53 and Rb tumor suppressor genes. OBJECTIVE: To investigate HPV 16 infection in cervical lesions, physical state of viral DNA and p53 gene alterations in a group of women attending a public health service. DESIGN: Prospective, non-controlled, transversal study. SETTING: Gynecological clinic of the School od Medicine, Universidade Federal Fluminense. SAMPLE: 43 consective patients with cervical lesions referred to our service. MAIN MEASUREMENTS: Cases were classified via cytology/histology as normal, HPV infection, condyloma, low-grade squamous intraepithelial lesion (LSIL), high-grade squamous intraepithelial lesion (HSIL) and carcinoma. HPV infection was studied via polymerase chain reaction (PCR) using two PCR primer sets, to determine DNA integration. p53 gene changes were investigated by single-strand conformation polymorphism (SSCP) analysis. RESULTS: One normal case, 7 HPV infections, 6 condylomas, 7 LSIL, 14 HSIL and 8 cancers were found, with 95 percent positive for HPV genome when tested using both L1 and E6 primers. HPV 16 was most prevalent (73.1 percent). HPV 16 DNA was integrated within the host genome in 3 LSIL. One LSIL progressed to HSIL by 13 months after first diagnosis. Among HPV 16-positive HSIL cases, 50 percent contained integrated viral DNA. HPV 16 E2 gene disruption was seen in 7 cancers (87.5 percent). Only smal-cell carcinoma showed intact HPV 16 E2 gene. Abnormal p53 bands detected by PCR/SSCP were observed in 4 cases: 2 squamous carcinoma with parametrium (exon 8) and two cervical intraepithelial neoplasia (CIN) III (exons 5 and 7). All cases presented HPV 16 E2 gene loss. CONCLUSIONS: The sample had a high rate of high-risk HPV detected in benign and malignant lesions; high cervical cancer burden; HPV 16 DNA integration in all except one case of cancer; p53 gene changes in CIN III and in invasive cancer cases associated with DNA integration