Association of human papillomavirus 16 E6 variants with cervical carcinoma and precursor lesions in women from Southern Mexico

Human Papillomavirus 16 Lineage D is Associated with High Risk of Cervical Cancer in the Brazilian Northeast Region

OBJECTIVE

 Similar to Human Papillomavirus (HPV) genotypes, different lineages of a genotype also have different carcinogenic capabilities. Studies have shown that specific genotype lineages of oncogenic HPV are associated with variable risks for the development of cervical intraepithelial neoplasia (CIN2/CIN3) and cervical cancer. The present study aimed to analyze the genetic diversity of the HPV16 genotype in women with CIN2/CIN3 and cervical cancer, from the northeast region of Brazil.

METHODS

 A cross-sectional multicenter study was conducted in the northeast region of Brazil, from 2014 to 2016. This study included 196 cases of HPV16 variants (59 and 137 cases of CIN2/CIN3 and cervical cancer, respectively). The difference of proportion test was used to compare patients with CIN2/CIN3 and cervical cancer, based on the prevalent HPV16 lineage (p < 0.05).

RESULTS

 According to the histopathological diagnosis, the percentage of lineage frequencies revealed a marginal difference in the prevalence of lineage A in CIN2/CIN3, compared with that in cervical cancer (p = 0.053). For lineage D, the proportion was higher in cancer cases (32.8%), than in CIN2/CIN3 cases (16.9%), with p = 0.023.

CONCLUSION

 HPV16 lineage A was the most frequent lineage in both CIN2/CIN3 and cervical cancer samples, while lineage D was predominant in cervical cancer, suggesting a possible association between HPV16 lineage D and cervical cancer.

Characterization of the Human Papillomavirus 16 Oncogenes in K14HPV16 Mice: Sublineage A1 Drives Multi-Organ Carcinogenesis

The study of human papillomavirus (HPV)-induced carcinogenesis uses multiple in vivo mouse models, one of which relies on the cytokeratin 14 gene promoter to drive the expression of all HPV early oncogenes. This study aimed to determine the HPV16 variant and sublineage present in the K14HPV16 mouse model. This information can be considered of great importance to further enhance this K14HPV16 model as an essential research tool and optimize its use for basic and translational studies. Our study evaluated HPV DNA from 17 samples isolated from 4 animals, both wild-type (n = 2) and HPV16-transgenic mice (n = 2). Total DNA was extracted from tissues and the detection of HPV16 was performed using a qPCR multiplex. HPV16-positive samples were subsequently whole-genome sequenced by next-generation sequencing techniques. The phylogenetic positioning clearly shows K14HPV16 samples clustering together in the sub-lineage A1 (NC001526.4). A comparative genome analysis of K14HPV16 samples revealed three mutations to the human papillomaviruses type 16 sublineage A1 representative strain. Knowledge of the HPV 16 variant is fundamental, and these findings will allow the rational use of this animal model to explore the role of the A1 sublineage in HPV-driven cancer.

Epidemiology and Molecular Biology of HPV Variants in Cervical Cancer: The State of the Art in Mexico

Cervical cancer (CC) continues to be a major public health problem in Mexico, ranking second among cancers in women. A persistent infection with human papillomaviruses (HPV) is the main risk factor for CC development. In addition, a significant fraction of other cancers including those of the anus, oropharynx, and penis are also related to HPV infection. In CC, HPV-16 is the most prevalent high-risk HPV type, followed by HPV-18, both being responsible for 70% of cases. HPV intratype variant lineages differ in nucleotide sequences by 1–10%, while sublineages differ by 0.5–1%. Several studies have postulated that the nucleotide changes that occur between HPV intratype variants are reflected in functional differences and in pathogenicity. Moreover, it has been demonstrated that HPV-16 and -18 intratype variants differentially affect molecular processes in infected cells, changing their biological behavior that finally impacts in the clinical outcome of patients. Mexico has participated in providing knowledge on the geographical distribution of intratype variants of the most prevalent HPVs in premalignant lesions of the cervix and cervical cancer, as well as in other HPV-related tumors. In addition, functional studies have been carried out to assess the cellular effects of intratype variations in HPV proteins. This review addresses the state of the art on the epidemiology of HPV-16 and HPV-18 intratype variants in the Mexican population, as well as their association with persistence, precancer and cervical cancer, and functional aspects related to their biological behavior.

Deep Sequencing of HPV16 E6 Region Reveals Unique Mutation Pattern of HPV16 and Predicts Cervical Cancer

The genetic diversity of human papillomavirus (HPV) 16 within cervical cells and tissue is usually associated with persistent virus infection and precancerous lesions. To explore the HPV16 mutation patterns contributing to the cervical cancer (CC) progression, a total of 199 DNA samples from HPV16-positive cervical specimens were collected and divided into high‐grade squamous intraepithelial lesion (HSIL) and the non‐HSIL(NHSIL) groups. The HPV16 E6 region (nt 7125-7566) was sequenced using next-generation sequencing. Based on HPV16 E6 amino acid mutation features selected by Lasso algorithm, four machine learning approaches were used to establish HSIL prediction models. The receiver operating characteristic was used to evaluate the model performance in both training and validation cohorts. Western blot was used to detect the degradation of p53 by the E6 variants. Based on the 13 significant mutation features, the logistic regression (LR) model demonstrated the best predictive performance in the training cohort (AUC = 0.944, 95% CI: 0.913–0.976), and also achieved a high discriminative ability in the independent validation cohort (AUC = 0.802, 95% CI: 0.601–1.000). Among these features, the E6 D32E and H85Y variants have higher ability to degrade p53 compared to the E6 wildtype (P < 0.05). In conclusion, our study provides evidence for the first time that HPV16 E6 sequences contain vital mutation features in predicting HSIL. Moreover, the D32E and H85Y variants of E6 exhibited a significantly higher ability to degrade p53, which may play a vital role in the development of CC.

IMPORTANCE The study provides evidence for the first time that HPV16 E6 sequences contain vital mutation features in predicting the high‐grade squamous intraepithelial lesion and can reduce even more unneeded colposcopies without a loss of sensitivity to detect cervical cancer. Moreover, the D32E and H85Y variants of E6 exhibited a significantly higher ability to degrade p53, which may play a vital role in the development of cervical cancer.

E6/E7 Variants of Human Papillomavirus 16 Associated with Cervical Carcinoma in Women in Southern Mexico

Persistent infection with the human papillomavirus 16 (HPV 16) is the cause of half of all cervical carcinomas (CC) cases. Moreover, mutations in the oncoproteins E6 and E7 are associated with CC development. In this study, E6/E7 variants circulating in southern Mexico and their association with CC and its precursor lesions were evaluated. In total, 190 DNA samples were obtained from scrapes and cervical biopsies of women with HPV 16 out of which 61 are from patients with CC, 6 from patients with high-grade squamous intraepithelial lesions (HSIL), 68 from patients with low-grade squamous intraepithelial lesions (LSIL), and 55 from patients without intraepithelial lesions. For all E7 variants found, the E7-C732/C789/G795 variant (with three silent mutations) was associated with the highest risk of CC (odd ratio (OR) = 3.79, 95% confidence interval (CI) = 1.46–9.85). The analysis of E6/E7 bicistron conferred to AA-a*E7-C732/C789/G795 variants revealed the greatest increased risk of CC (OR = 110, 95% CI = 6.04–2001.3), followed by AA-c*E7-C732/C789/G795 and A176/G350*E7-p. These results highlight the importance of analyzing the combinations of E6/E7 variants in HPV 16 infection and suggest that AA-a*E7-C732/C789/G795, AA-c*E7-C732/C789/G795, and A176/G350*E7-p can be useful markers for predicting CC development.

Degradation of p53 by HPV16-E6 variants isolated from cervical cancer specimens of Moroccan women

Cervical cancer is the second most diagnosed cancer in Moroccan women. The main etiological factor for developing cervical cancer is the persistent infection with HPV16. Genetic studies have reported the occurrence of amino acid variations within the E6 oncoprotein that promotes host cell transformation by targeting p53 for degradation. To verify the biological effects of E6 polymorphisms towards p53 degradation, HPV16-E6 prototype and 7 variants isolated from cervical cancer biopsies of Moroccan women were evaluated for their activities by transient expression assays using pcDNA3.1-E6 constructs in C33A cell line. Expression of E6 genes in transfected cells was detected with reverse transcription PCR (RT-PCR), then, p53 levels were evaluated by western blot analysis. Significant dissimilarities in p53 degradation activities of HPV16-E6 prototype and intratypic variants were noticed. As compared to the prototype, the highest p53 degradation were exhibited by the African variants Af2-a/r, Af1-d/G295 and Af2-a/G285 (p < 0.001), followed by the European variants E- C442/G350 and E-G350/r (p < 0.01), then, the North American variant NA1-b/r (p < 0.05). The inter-variant differences were statistically significant between Af2-a/r variant and the North American variants NA1-b/r and NA1 (p < 0.05). Thus, the Af2-a/r variant was significantly more active in degrading p53 in our in vitro experiments (p < 0.0001). Our findings support the fact that HPV16-E6 variations have a biological impact on degrading p53, and so, represent a significant carcinogenic potential for developing cervical cancer.

Effect of HPV 16 E6 Oncoprotein Variants on the Alterations of the Proteome of C33A Cells

BACKGROUND/AIM

The E6 genotypic variants of HPV 16 identified in lesions of women with cervical cancer (CC) in Southern of Mexico include the E-G350, AAa, AAc, E-C188/G350, and E-A176/G350, transcriptomic analysis cells transfected with those variants showed to induce differential expression of the host genes involved in the development of CC, the aim of this work was to understand how the over-expression of the E6 oncoprotein and its variants can induce molecular mechanisms that lead to more aggressive HPV 16 phenotypes in cervical cancer and which proteins could be associated with the process.

MATERIALS AND METHODS

Total extracts from C33A, C33A mock, C33A AAa, C33A E-C188/G350, C33A E-A176/G350, and C33A E-prototype cells were analyzed using 2D electrophoresis, PDQuest software and mass spectrometry, validation of results was performed through qPCR.

RESULTS

Statistically significant differential expression of 122 spots was detected, 12 of the identified proteins were associated with metabolism and metabolic programming. Out of these CCT8, ENO and ALDH1A were further validated.

CONCLUSION

CCT8 and ALDH1A were found to be over-expressed in C33A AAa and C33A E-A176/G350, compared to the E prototype. Both proteins could be associated with a most aggressive phenotype due to their relationship with metabolism, protein folding and stemness, mechanisms associated to E6 that could be useful in the design of new therapies.

Metabolic Reprogramming in Cancer: Role of HPV 16 Variants

Metabolic reprogramming is considered one of the hallmarks in cancer and is characterized by increased glycolysis and lactate production, even in the presence of oxygen, which leads the cancer cells to a process called “aerobic glycolysis” or “Warburg effect”. The E6 and E7 oncoproteins of human papillomavirus 16 (HPV 16) favor the Warburg effect through their interaction with a molecule that regulates cellular metabolism, such as p53, retinoblastoma protein (pRb), c-Myc, and hypoxia inducible factor 1α (HIF-1α). Besides, the impact of the E6 and E7 variants of HPV 16 on metabolic reprogramming through proteins such as HIF-1α may be related to their oncogenicity by favoring cellular metabolism modifications to satisfy the energy demands necessary for viral persistence and cancer development. This review will discuss the role of HPV 16 E6 and E7 variants in metabolic reprogramming and their contribution to developing and preserving the malignant phenotype of cancers associated with HPV 16 infection.

An increase of microRNA-16-1 is associated with the high proliferation of squamous intraepithelial lesions in the presence of the integrated state of HR-HPV in liquid cytology samples

Studies of cervical cancer (CC) have reported that microRNA-16-1 (miR-16-1), which is an oncomiR, is increased in the tissues and cell lines of CC. The aim of the present study was to investigate the association of miRNA-16-1 expression level with squamous cell carcinoma (SCC), the presence of squamous intraepithelial lesions (SIL) and the integration of high-risk human papillomavirus (HR-HPV) DNA. The current study analyzed 80 samples obtained from women by liquid-based cytology, which revealed that 20 were negative for SIL (NSIL) and without HPV, 20 were low-grade SIL (LSIL), 20 were high-grade SIL (HSIL), and 20 were diagnosed as SCC with HR-HPV. The genotyping of the viral DNA was conducted via an INNO-LiPA-HPV array, the expression of miR-16-1 was determined by reverse transcription-quantitative PCR, and the physical state of the HR-HPV was ascertained by in situ hybridization with amplification with tyramide. A total of eight HR-HPV genotypes were distinguished; the most frequent of these being HPV16, followed by multiple infection with HR-HPV (including HPV16). The mixed state of the HR-HPV was observed in 60 and 65% of LSIL and HSIL cases, respectively, while an integrated HR-HPV state was identified in 90% of cases with SCC. The expression level of miR-16-1 increased according to the grade of SIL, and cases with HSIL exhibited a significantly higher miR-16-1 expression level compared with women with NSIL (P<0.001; Table II). It can therefore be determined that the expression of miR-16-1 effects cellular proliferation, due to the viral integration of various HR-HPV genotypes in unique infection or in multiple infection. Thus, the overexpression of miR-16-1 could be monitored in women with LSIL, in order to discard a major lesion.

Role of HPV 16 variants among cervical carcinoma samples from Northeastern Brazil

BACKGROUND

Cervical cancer is the fourth most common type of cancer affecting women globally. In Brazil, it is the third most frequent type of cancer in women and HPV is present in approximately 90% of cases. Evidence suggests that variants of HPV 16 can interfere biologically and etiologically during the development of cervical cancer.

METHODS

Cervix tumor fragments were collected, their DNA was extracted, and nested PCR was used to detect HPV. Positive samples were sequenced to determine the viral genotype. To characterize the HPV 16 strains, positive samples PCR was used to amplify the LCR and E6 regions of the HPV 16 virus.

RESULTS

Data from 120 patients with cervical cancer were analyzed. Most women were between 41 and 54 years of age, had schooling until primary school, a family income between 1 and 2 times the minimum wage and were married/in a consensual union. There was no statistically significant association between HPV or socio-demographic variables and risk factors for cervical cancer (P <  0.05). HPV was present in 88 women (73%). The most prevalent types were HPV 16 (53.4%), HPV 18 (13.8%), HPV 35 (6.9%) and HPV 45 (5.7%). Of the 47 HPV 16 positive cases, variant A (49%) was present in 23 samples, followed by variant D in 20 cases (43%), and variants B and C in 2 cases each (4%). The most prevalent histological type of HPV 16 tumors was squamous cell carcinoma, followed by adenocarcinoma. There was a statistically significant association between HPV 16 variants and the tumors' histological types (P <  0.001).

CONCLUSIONS

Knowledge of HPV 16 variants will provide data on their influence on the pathological and oncogenic aspects of cervical lesions.

Prevalence of human papillomavirus in the oral cavity of an indigenous community from Southwest México

Human papilloma virus (HPV) is a DNA virus associated with the development of cervical, penile, anal, vulvar, and oral cancers. In recent years, there has been an increase in oral cancer, which could be due to changes in sexual behavior in the general population. In México, there is scarce information on this regard, which prompted us to study HPV infection prevalence in the oral cavity of an indigenous community from the municipality of Siltepec, Chiapas, Mexico. Oral samples from 198 individuals were obtained with cytobrush for virus detection by nested PCR, using MY09/MY11 and GP5+/GP6+ primers, and positive samples were sequenced for HPV genotyping. We observed 12.1% HPV infection prevalence, which depended on gender, number of sexual partners, lack of using condoms, and oral sex practices. In contrast, no significant association between HPV infection and tobacco or alcohol consumption was detected. Furthermore, sequencing analyzes were performed where HPV-13 (21/24), -16 (2/24), -32 (1/24), -81 (1/24), and -83 (1/24) were evidenced and HPV-16 European/Asian and Asian/American E6 variants identified. These results demonstrated an important prevalence of HPV infection in the oral cavity of a Mexican indigenous community, where the predominant genotypes were associated with benign pathologies, and showed that high-risk genotype variants derived from different lineages.

The contribution of Latin American research to HPV epidemiology and natural history knowledge

Our aim was to review the major contributions of studies conducted in different Latin American (LA) countries to the field of human papillomavirus (HPV) epidemiology, natural history, risk of disease, and prevention strategies, mainly in the uterine cervix. Although cytological screening is established in several countries in LA, incidence and mortality rates from cervical cancer (CC) are still extremely high. Finally, data from large cohort studies conducted in LA countries provided seminal data to propose primary and secondary prevention modalities: the HPV vaccine has been introduced in the national immunization programs of several LA countries and multiple screening experiences using HPV testing are under evaluation in the region.

Mutational landscape and intra-host diversity of human papillomavirus type 16 long control region and E6 variants in cervical samples

Human papillomavirus genotype 16 (HPV16) is the most frequent high-risk HPV (HR-HPV) identified in cervical precursor lesions and cervical cancer (CC) worldwide. The oncogenic potential of HPV16 is partly dependent on the lineage involved in the infection and the presence of clinically relevant mutations. In this report, we present the distribution of HR-HPV and the mutational profile and intra-host variability of HPV16 lineages, based on analysis of the long control region (LCR) and the E6 gene in samples with normal cytology (n = 39), squamous intraepithelial lesions (n = 25), and CC (n = 39). HR-HPV genotyping was performed using multiplex real-time PCR. HPV16 lineage assignments and mutation frequencies were determined by conventional PCR and Sanger DNA sequencing, and intra-patient viral populations were analyzed using next-generation sequencing (NGS). The most frequent HR-HPV type was HPV16, followed by HPV31 and HPV18. The frequency of HPV16 sublineages was A1/A2 > D2 > D3 and B1. Moreover, the most frequent mutations, both in samples from this study and in the available sequences from Mexican isolates in the GenBank database were LCR-G7518A, which is involved in carcinogenesis, and E6-T350G (producing L83V), associated with persistence of infection. Otherwise, deep sequencing revealed high conservation of viral lineages and mutations, independently of the stages studied. In conclusion, the high frequency and stability of these molecular markers, as well as the circulating viral lineages, could be related to the incidence of CC associated with HPV16. Hence, they deserve a broader analysis to determine the risk of specific populations for progression of the disease.

In silico prediction of structural changes in human papillomavirus type 16 (HPV16) E6 oncoprotein and its variants

Background

HPV16 infection is one of the main risk factors involved in the development of cervical cancer, mainly due to the high oncogenic potential of the viral proteins E6 and E7, which are involved in the different processes of malignant transformation. There is a broad spectrum of intratypical variation of E6, which is reflected in its high diversity, biological behavior, global distribution and risk of causing cervical cancer. Experimental studies have shown that the intratypical variants of the protein E6 from the European variants (E-G350, E-A176/G350, E-C188/G350) and Asian-American variants (AAa and AAc), are capable of inducing the differential expression of genes involved in the development of cervical cancer.

Results

An in silico analysis was performed to characterize the molecular effects of these variations using the structure of the HPV16 E6 oncoprotein (PDB: 4XR8; chain H) as a template. In particular, we evaluated the 3D structures of the intratypical variants by structural alignment, ERRAT, Ramachandran plots and prediction of protein disorder, which was further validated by molecular dynamics simulations. Our results, in general, showed no significant changes in the protein 3D structure. However, we observed subtle changes in protein physicochemical features and structural disorder in the N- and C-termini.

Conclusions

Our results showed that mutations in the viral oncogene E6 of six high-risk HPV16 variants are effectively neutral and do not cause significant structural changes except slight variations of structural disorder. As structural disorder is involved in rewiring protein-protein interactions, these results suggest a differential pattern of interaction of E6 with the target protein P53 and possibly different patterns of tumor aggressiveness associated with certain types of variants of the E6 oncoprotein.

Electronic supplementary material

The online version of this article (10.1186/s12860-019-0217-0) contains supplementary material, which is available to authorized users.

Pre-vaccination prevalence of anogenital and oral human papillomavirus in young HIV-infected men who have sex with men

The aims of this study were to: 1) determine prevalence of anogenital and oral HPV, 2) determine concordance between HPV at anal, perianal, scrotal/penile, and oral sites; and 3) describe factors associated with anogenital HPV types targeted by the 9-valent vaccine. Data were collected from 2012 to 2015 among men who have sex with men 18-26 years of age enrolled in a vaccine trial (N = 145). Penile/scrotal, perianal, anal, and oral samples were tested for 61 HPV types. Logistic regression was used to identify factors associated with types in the 9-valent vaccine. Participants' mean age was 23.0 years, 55.2% were African-American, and 26.2% were Hispanic; 93% had anal, 40% penile, and 6% oral HPV. Among those with anogenital infection, 18% had HPV16. Concordance was low between anogenital and oral sites. Factors independently associated with a 9-valent vaccine-type HPV were: race (African-American vs. White, OR=2.67, 95% CI=1.11-6.42), current smoking (yes vs. no, OR=2.37, 95% CI=1.03-5.48), and number of recent receptive anal sex partners (2+ vs. 0, OR=3.47, 95% CI=1.16-10.4). Most MSM were not infected with HPV16 or HPV18, suggesting that they may still benefit from HPV vaccination, but anogenital HPV was very common, highlighting the importance of vaccinating men before sexual initiation. CLINICAL TRIAL NUMBER: NCT01209325.

Human papillomavirus type 16 E6 and E7 gene variations associated with cervical cancer in a Han Chinese population

BACKGROUD

Human papillomavirus type 16 (HPV16) is a high-risk HPV subtype and a potent carcinogen. The HPV16 E6 and E7 genes are considered oncogenes that play a core role in the development of cervical cancer.

METHODS

In the current study, we enrolled 97 HPV16-positive cervical cancer patients (case group) and 136 HPV16-positive asymptomatic individuals (control group) in a study to analyse the association between HPV16 E6 and E7 gene variations and cervical cancer.

RESULTS

Our results showed that three HPV16 sub-lineages (A1-A3, A4 and D3) were present; the distribution of these variants between the case and control group was not significantly different (P = 0.178). When the distribution of the HPV16 E6 and E7 gene variations was compared, the distribution of only A131C (R10R) in the E6 gene showed a different trend between the case and control groups and C749T (S63F) in the E7 gene was significantly different between the case and control groups (P = 0.071 and P = 4.861 × 10^-10, respectively). Regarding the sub-lineages, no variations in the E6 gene were significantly different between the case and control group for the A4 (As) and A1-A3 (EUR) sub-lineages. However, the distribution of C749T (S63F) in the E7 gene was significantly different between the case and control groups for the A4 (As) and A1-A3 (EUR) sub-lineages (P = 1.815 × 10^-8 and P = 0.008). In the current study, we found that the C749T (S63F) variation in the HPV16 E7 gene was associated with cervical cancer not only in the A4 (As) sub-lineage but also in the A1-A3 (EUR) sub-lineage.

CONCLUSION

Our study will provide a good reference for further functional studies of the relationship between cervical cancer carcinogenesis and the HPV16 E6 and E7 genes.

Findings of multiple HPV genotypes in cervical carcinoma are associated with poor cancer-specific survival in a Swedish cohort of cervical cancer primarily treated with radiotherapy

Cervical cancer (CC) is one of the most common cancers in women and virtually all cases of CC are a result of a persistent infection of human papillomavirus (HPV). For disease detected in early stages there is curing treatment but when diagnosed late with recurring disease and metastasis there are limited possibilities. Here we evaluate HPV impact on treatment resistance and metastatic disease progression. Prevalence and distribution of HPV genotypes and HPV16 variants in a Swedish CC patient cohort (n=209) was evaluated, as well as HPV influence on patient prognosis. Tumor samples suitable for analysis (n=204) were genotyped using two different real-time PCR methods. HPV16 variant analysis was made using pyrosequencing. Results showed that HPV prevalence in the total series was 93%. Of the HPV-positive samples, 13% contained multiple infections, typically with two high-risk HPV together. Primary cure rate for the complete series was 95%. Recurrence rate of the complete series was 28% and distant recurrences were most frequent (20%). Patients with tumors containing multiple HPV-strains and particularly HPV genotypes belonging to the alpha 7 and 9 species together had a significantly higher rate of distant tumor recurrences and worse cancer-specific survival rate.

Methylation of the L1 gene and integration of human papillomavirus 16 and 18 in cervical carcinoma and premalignant lesions

High-risk human papillomavirus (HPV) is the primary cause of cervical carcinoma (CC). Viral integration into the host chromosomes is associated with neoplastic progression, and epigenetic changes may occur as a result. The objective of the present study was to analyze HPV L1 gene methylation and to compare the use of quantitative polymerase chain reaction (qPCR), in situ hybridization (ISH) and L1 methylation analysis as methods for detecting HPV integration. Cervical scrapes or biopsy samples positive for HPV 16 or 18, from 187 female patients with CC, squamous intraepithelial lesions (SILs) or no intraepithelial lesion (non-IL) were analyzed. Methylation of the L1 gene was determined using bisulfite modification followed by PCR, and HPV integration was subsequently analyzed. HPV 16 L1 gene methylation was revealed to increase with histological grade, with statistically significant differences observed as follows: Low-grade SIL vs. CC, P<0.0001 and non-IL vs. CC, P<0.0001. HPV 18 L1 gene methylation also increased according to histological grade, however, no statistically significant differences were observed. Methylation at CpG site 5608 of the HPV 16 L1 gene was associated with all grades of cervical lesions, whereas methylation at CpG site 5617 demonstrated the strongest association with CC (odds ratio, 42.5; 95% confidence interval, 4.7-1861; P<0.0001). The concordance rates between the various methods for the detection of the physical status of HPV 16 and HPV 18 were 96.1% for qPCR and ISH, 76.7% for qPCR and L1 gene methylation, and 84.8% for ISH and L1 gene methylation. In conclusion, methylation of the HPV 16 L1 gene increases significantly according to the grade of the cervical lesion, and methylation at CpG sites 5608 and 5617 of this gene may be used as prognostic biomarkers. ISH and L1 gene methylation have good concordance with qPCR with regards to the detection of HPV integration. Therefore, these are useful methods in determining the physical state of HPV.

Human papillomavirus type distribution and HPV16 intratype diversity in southern Brazil in women with and without cervical lesions

BACKGROUND

Increasing evidence suggests that human papillomavirus (HPV) intratype variants (specific lineages and sublineages) are associated with pathogenesis and progression from HPV infection to persistence and the development of cervical cancer.

OBJECTIVES

This study aimed to verify the prevalence of HPV infection and distribution of HPV types and HPV16 variants in southern Brazil in women with normal cytology or intraepithelial lesions.

METHODS

HPV typing was determined by L1 gene sequencing. To identify HPV16 variants, the LCR and E6 regions were sequenced, and characteristic single nucleotide variants were identified.

FINDINGS

A total of 445 samples were studied, with 355 from cervical scrapes and 90 from cervical biopsies. HPV was detected in 24% and 91% of these samples, respectively. The most prevalent HPV types observed were 16 (cervical, 24%; biopsies, 57%) and 58 (cervical, 12%; biopsies, 12%). Seventy-five percent of the HPV16-positive samples were classified into lineages, with 88% defined as lineage A, 10% as lineage D, and 2% as lineage B.

MAIN CONCLUSIONS

This study identified a high frequency of European and North American HPV16 lineages, consistent with the genetic background of the human population in southern Brazil.

Differential proteins among normal cervix cells and cervical cancer cells with HPV-16 infection, through mass spectrometry-based Proteomics (2D-DIGE) in women from Southern México

Background

Cervical cancer (CC) is the fourth most common cancer in women worldwide with an estimated 528,000 new cases in 2012. The same year México had an incidence of 13,960 and a mortality of 4769 cases. There are several diagnosis methods of CC; among the most frequents are the conventional Pap cytology (Pap), colposcopy, and visual inspection with acetic acid (VIA), histopathological examination, tests of imaging and detection of high-risk papilloma virus (HR-HPV) with molecular tests (PCR, hybridization, sequencing). Proteomics is a tool for the detection of new biomarkers that can be associated with clinical stage, histological type, prognosis, and/or response to treatment. In this study we performed a comparative analysis of CC cells with normal cervical cells. The proteomic analysis was carried out with the fluorescent two-dimensional electrophoresis (2D-DIGE) technique to subsequently identify differential protein profiles using Decyder Software, and the selected proteins were identified by Mass Spectrometry (MALDI-TOF).

Results

The proteins that showed an increased expression in cervical cancer in comparison with normal cervix cells were: Mimecan, Actin from aortic smooth muscle and Lumican. While Keratin, type II cytoskeletal 5, Peroxiredoxin-1 and 14-3-3 protein sigma showed a decrease in their protein expression level in cervical cancer in comparison with normal cervix cells.

Conclusions

Thus, this study was successful in identifying biomarker signatures for cervical cancer, and might provide new insights into the mechanism of CC progression.

The Asian-American variant of human papillomavirus type 16 exhibits higher activation of MAPK and PI3K/AKT signaling pathways, transformation, migration and invasion of primary human keratinocytes

Asian-American (AA) HPV-16 variants are associated with higher risk of cancer. Abnormal activation of intracellular signaling play a critical role in cancer development and progression. Our aim was to elucidate mechanisms underlying the higher oncogenic potential attributed to AA variant. We evaluated activation of MAPK and PI3K/AKT pathways in primary human keratinocytes (PHKs) transduced with E6/E7 of three HPV-16 variants: E-P, AA, E-350G. Phenotypes examined included migration, anchorage independent growth and invasion. AA PHKs presented the highest levels of active proteins involved in all cascades analyzed: MAPK-ERK, MAPK-p38 and PI3K-AKT. AA PHKs were more efficient in promoting anchorage independent growth, and in stimulating cell migration and invasion. MEK1 inhibition decreased migration. The mesenchymal phenotype marker vimentin was increased in AA PHKs. Our results suggest that MEK1, ERK2, AKT2 hyperactivation influence cellular behavior by means of GSK-3b inactivation and EMT induction prompting AA immortalized PHKs to more efficiently surpass carcinogenesis steps.

Changes in global gene expression profiles induced by HPV 16 E6 oncoprotein variants in cervical carcinoma C33-A cells

We analyzed the effects of the expression of HPV 16 E6 oncoprotein variants (AA-a, AA-c, E-A176/G350, E-C188/G350, E-G350), and the E-Prototype in global gene expression profiles in an in vitro model. E6 gene was cloned into an expression vector fused to GFP and was transfected in C33-A cells. Affymetrix GeneChip Human Transcriptome Array 2.0 platform was used to analyze the expression of over 245,000 coding transcripts. We found that HPV16 E6 variants altered the expression of 387 different genes in comparison with E-Prototype. The altered genes are involved in cellular processes related to the development of cervical carcinoma, such as adhesion, angiogenesis, apoptosis, differentiation, cell cycle, proliferation, transcription and protein translation. Our results show that polymorphic changes in HPV16 E6 natural variants are sufficient to alter the overall gene expression profile in C33-A cells, explaining in part the observed differences in oncogenic potential of HPV16 variants.