Tumour suppressor gene methylation and cervical cell folate concentration are determinants of high-risk human papillomavirus persistence: a nested case control study

Performance of Human Gene EPB41L3 and HPV 16/18 Viral DNA Methylation to Triage hrHPV-Positive Women

More evidence from population-based cohort studies is required to confirm the application of methylation-based biomarkers in real-world settings. The cross-sectional and 24-month cumulative triage performance of a novel methylation assay targeting the host gene EPB41LE and HPV16/18 DNA L1/L2 regions among hrHPV-positive women was evaluated based on a population-based cohort study from China. Overall methylation positivity was 12.4% among hrHPV-positive women. Methylation-positive women had significantly higher risks of hrHPV persistence at 12M and 24M follow-up (RR12M = 1.9, 95%CI: 1.5-2.6 and RR24M = 1.7, 95%CI: 1.2-2.5). For CIN2+, cross-sectional triage sensitivity of methylation was similar to HPV16/18 (70.6% vs. 64.7%, pexact = 1.000), but was lower than cytology (94.1%), although not significantly (pexact = 0.213). The specificity (91.2%) of methylation was significantly higher than other triage methods (p < 0.001 for all). The longitudinal sensitivity of methylation over 24M follow-up was 56.0%, lower (but not significantly so) than HPV16/18 (64.0%, pexact = 0.688) and cytology (76.0%, pexact = 0.125). Methylation testing showed high positive predictive values for CIN2+ (41.4% at baseline, 50.0% at 24-month), while the CIN2+ risk of methylation negative women (cNPV) remained considerable (2.5% at baseline, 6.9% at 24-month). Study findings indicate that methylation has better specificity and predictive values for the presence or development of cervical precancer and might therefore be considered for the strategy of HPV screening and methylation triage followed by immediate treatment of triage-positive women and delayed follow-up of hrHPV-positive/methylation-negative women.

Relationship between vaginal microecological changes and oncogene E6/E7 and high-risk human papillomavirus infection

High-risk (HR)-human papillomavirus (HPV) is the leading cause of precancerous cervical lesions in patients with chronic untreated infection. We investigated the relationships among several vaginal microbiological alterations, oncogene E6/E7 expression, and HR-HPV. A total of 1327 women who underwent HPV screening, vaginal microecology determination, and fluid-based thin-layer cytological test were enrolled and classified into the HPV-negative group, the low-risk (LR)-HPV-positive group, and the HR-HPV-positive group. The status of cervical HPV infection, vaginal microecology, and E6/E7 mRNA expression were examined sequentially. The effect of HR-HPV infection on cervical cancer (CC) was meticulously assessed, and associations between HR-HPV infection and vaginal microecology and E6/E7 mRNA were identified. In total 548/1327 patients were HPV positive, including LR-HPV infection (N = 132) and HR-HPV infection (N = 416). Patients in the HR-HPV positive group revealed higher detection rates of bacterial vaginosis (BV), trichomonal vaginitis (TV), and vulvovaginal candidiasis (VVC) relative to the HPV negative group. A higher E6/E7 mRNA expression was identified in HR-HPV patients compared to LR-HPV patients. BV and E6/E7 mRNA were classified as independent risk factors for HR-HPV infection. Patients with HR-HPV infection were more susceptible to CC development. Overall, BV and E6/E7 mRNA expression were identified as independent risk factors for HR-HPV infection.IMPACT STATEMENTWhat is already known on this subject? Through literature review, we found that vaginal ecological changes increase the risk of HPV infection, and HPV persistent infection is an important risk factor for cervical precancerous lesions and cervical cancer. In addition, HPV gene E6/E7 is expressed in HPV-positive cervical cancer cells, which is related to cell malignant transformation and even tumorigenesis.What do the results of this study add? This study further revealed that bacterial vaginosis (BV) and E6/E7 mRNA were independently correlated with HR-HPV infection, and HR-HPV infection increased the risk of cervical cancer.What are the implications of these findings for clinical practice and/or further research? E6/E7 mRNA detection may be used as a new auxiliary diagnostic index for HR-HPV infection. In addition, this study provides a reference for whether the restoration of vaginal microecological balance in patients with BV undergoing clinical treatment is conducive to HR-HPV regression, and provides theoretical support for the prevention and control of cervical cancer microecological approach and the occurrence and development of cervical cancer.

Associations of RBC and Serum Folate Concentrations with Cervical Intraepithelial Neoplasia and High-Risk Human Papillomavirus Genotypes in Female Chinese Adults

BACKGROUND

Although folate status is associated with cervical carcinogenesis, it is not clear whether folate deficiency is associated with risk of cervical intraepithelial neoplasia (CIN) progression and infection with high-risk human-papillomavirus (hrHPV).

OBJECTIVES

To evaluate the associations of RBC and serum folate concentrations with prevalence of CIN grades and hrHPV infection, their interactions with prevalence of CIN grades, and RBC folate with the risk of CIN1 progressing to CIN2.

METHODS

Using data from the Shanxi CIN cohort of 2304 female Chinese adults, we used logistic-regression model to estimate ORs and prevalence ratios (PRs) of RBC and serum folate concentrations with prevalence of CIN grades and hrHPV infection. Categoric and spline analyses were used to evaluate the dose-response relations. We estimated the association of RBC folate with risk of CIN1 progressing to CIN2 in the nested case-control cohort.

RESULTS

An inverse association was observed between increased RBC folate concentration and the odds of all CIN grades [quartile 1 (Q1) compared with Q4: OR: 2.28; 95% CI: 1.77, 2.93; Ptrend < 0.001]. Significant interaction of RBC folate and hrHPV infection was observed for prevalence of CIN2 or above (Pinteraction < 0.01). No associations were found between RBC and serum folate with PRs of hrHPV in each CIN grade. Over a median follow-up of 21.0 mo, RBC folate was associated with increased risk of CIN1 progressing to CIN2 (Q1 compared with Q4: OR: 3.86; 95% CI: 1.01, 14.76).

CONCLUSIONS

Our study indicates that RBC folate concentration is associated with prevalence of CIN grades and CIN1 progression in female Chinese adults. Maintenance of normal folate status is important for reducing the risk of CIN and its progression in women with or without hrHPV infection.

Levels of Folate and Vitamin B12, and Genetic Polymorphisms Involved in One-Carbon Metabolism May Increase the Risk of Cervical Cytological Abnormalities

To analyze the association of cervical cytological abnormalities with genetic polymorphisms of enzymes involved in folate metabolism, and the effect of micronutrients on association of polymorphisms with cervical carcinogenesis. Our samples were divided in Control (120 women with normal cytology), and Cases: 37 women with Atypical Squamous Cells of Undetermined Significance(ASC-US), 33 participants presenting Low-Grade Squamous Intraepithelial Lesion(LSIL), and 24 women presenting High-Grade cervical lesions(HSIL/ASC-H). We obtained cervical samples for cytological analysis, HPV detection, and analysis of polymorphisms and cervical cell folate. Blood samples were obtained for serum folate and vitamin B12 evaluation. To analyze all polymorphisms simultaneously, we calculated Genetic Risk Score(GRS). Median concentrations were used as cutoff for determination of micronutrient levels. We observed no differences of genotype or allelic frequencies of polymorphisms according to cervical lesions. However, high levels of cervical cell folate and high number of genetic alterations increased risk of High-Grade lesions [OR(IC95%):1.85(0.42-8.11)]. Instead, women with vitamin B12 ≤ 274 pg/ml and GRS ≥ 3 presented even greater risk of HSIL/ASC-H [OR(IC95%):2.91(0.46-18.62)]. High frequency of genetic polymorphisms involved in one-carbon metabolism associated with high levels of cell folate or low levels of serum vitamin B12, increased the risk of High-Grade lesion in uterine cervix.

Regulatory Non-coding RNAs for Death Associated Protein Kinase Family

The death associated protein kinases (DAPKs) are a family of calcium dependent serine/threonine kinases initially identified in the regulation of apoptosis. Previous studies showed that DAPK family members, including DAPK1, DAPK2 and DAPK3 play a crucial regulatory role in malignant tumor development, in terms of cell apoptosis, proliferation, invasion and metastasis. Accumulating evidence has demonstrated that non-coding RNAs, including microRNA (miRNA), long non-coding RNA (lncRNA) and circRNA, are involved in the regulation of gene expression and tumorigenesis. Recent studies indicated that non-coding RNAs participate in the regulation of DAPKs. In this review, we summarized the current knowledge of non-coding RNAs, as well as the potential miRNAs, lncRNAs and circRNAs, that are involved in the regulation of DAPKs.

Oral human papillomavirus infection in England and associated risk factors: a case-control study

OBJECTIVES

This study was conducted to determine the prevalence of and associated risk factors for infection with oral high-risk human papillomavirus (HR-HPV) in adult participants within England, and to explore any association with oral mucosal buccal epithelial cell and whole blood folate concentration.

DESIGN

This was an observational study to determine oral HR-HPV prevalence in the study population. A case-control study was performed to explore the association between infection and folate status.

SETTING

This study was conducted in Sheffield, UK, between April 2013 and August 2014.

PARTICIPANTS

Seven hundred participants, aged 18-60 years, were recruited from university students (n=179), university and hospital staff (n=163), dental hospital patients (n=13), Sexual Health Sheffield patients (n=122) and the general public (n=223).

INTERVENTIONS

Participants completed a lifestyle and sexual behaviour questionnaire, provided an oral rinse and gargle sample for the detection of oral HR-HPV and an oral mucosal buccal epithelial cell sample for the measurement of oral mucosal buccal epithelial cell folate. A blood sample was collected for measurement of whole blood folate concentration.

OUTCOME MEASURES

The prevalence of oral HR-HPV infection in the study population was the primary outcome measure. Secondary outcome measures included associations between risk factors, folate status and infection.

RESULTS

The prevalence of oral HR-HPV infection in this cohort was 2.2% (15/680) with 0.7% (5/680) positive for HPV16 or HPV18. Twenty samples were excluded due to insufficient material for HPV detection. Participants with oral HR-HPV infection were more likely to be a former smoker, and have a greater number of sexual and oral sexual partners. Folate status was not linked to likelihood of HPV infection.

CONCLUSIONS

The prevalence of oral infection with HR-HPV in adult men and women in Sheffield in the North of England was low. Smoking and sexual behaviour were associated with HR-HPV positivity.

TRIAL REGISTRATION NUMBER

ID14106.

Methyl-donor depletion of head and neck cancer cells in vitro establishes a less aggressive tumour cell phenotype

PURPOSE

DNA methylation plays a fundamental role in the epigenetic control of carcinogenesis and is, in part, influenced by the availability of methyl donors obtained from the diet. In this study, we developed an in-vitro model to investigate whether methyl donor depletion affects the phenotype and gene expression in head and neck squamous cell carcinoma (HNSCC) cells.

METHODS

HNSCC cell lines (UD-SCC2 and UPCI-SCC72) were cultured in medium deficient in methionine, folate, and choline or methyl donor complete medium. Cell doubling-time, proliferation, migration, and apoptosis were analysed. The effects of methyl donor depletion on enzymes controlling DNA methylation and the pro-apoptotic factors death-associated protein kinase-1 (DAPK1) and p53 upregulated modulator of apoptosis (PUMA) were examined by quantitative-PCR or immunoblotting.

RESULTS

HNSCC cells cultured in methyl donor deplete conditions showed significantly increased cell doubling times, reduced cell proliferation, impaired cell migration, and a dose-dependent increase in apoptosis when compared to cells cultured in complete medium. Methyl donor depletion significantly increased the gene expression of DNMT3a and TET-1, an effect that was reversed upon methyl donor repletion in UD-SCC2 cells. In addition, expression of DAPK1 and PUMA was increased in UD-SCC2 cells cultured in methyl donor deplete compared to complete medium, possibly explaining the observed increase in apoptosis in these cells.

CONCLUSION

Taken together, these data show that depleting HNSCC cells of methyl donors reduces the growth and mobility of HNSCC cells, while increasing rates of apoptosis, suggesting that a methyl donor depleted diet may significantly affect the growth of established HNSCC.

Folate deficiency and aberrant DNA methylation and expression of FHIT gene were associated with cervical pathogenesis

Aberrant DNA methylation is a recognized feature in various types of human cancer, and folate has a vital role in the epigenetics of mammalian cells by supplying methyl groups for DNA methylation reactions. Fragile histidine triad (FHIT) is a tumor suppressor gene that is frequently silenced in cervical cancer (CC) and preneoplastic lesions. Promoter hypermethylation was previously observed in CC, and its epigenetic silencing has been observed at mRNA or protein levels. Changes in folate intake to modulate DNA methylation may be a mechanistic link to cancer, but this remains to be elucidated. The aim of the present study was to evaluate the influences of folate on FHIT gene methylation and expression in the progression of cervical cancerization. In the present study, red blood cell (RBC) folate levels, FHIT gene methylation status, and mRNA and protein expression levels were detected in 254 women, including normal cervix (NC, n=80), cervical intraepithelial neoplasm grade 1 (CIN1, n=55; CIN2/3, n=55) and cervical squamous cell carcinoma (SCC, n=64) samples. The methylation status of FHIT gene and its mRNA and protein expression levels were measured in CaSki (HPV16 positive) and C33A (HPV16 negative) CC cells treated with different concentrations of folate. The results indicated that FHIT gene methylation rate increased with the severity of cervix lesions, however, RBC folate levels, FHIT mRNA and protein expression levels were reduced. The proliferation inhibition rate, apoptosis rate, and FHIT protein and mRNA expression levels increased along with rising concentrations of folate, whereas the degree of FHIT gene methylation gradually weakened in CaSki or C33A cell lines. The present findings indicated that folate deficiency, FHIT gene promoter hypermethylation and reduced expression were significantly associated with cervical carcinogenesis. The results indicated that folate was able to enhance apoptosis and inhibit the cervical cell proliferation while regulating FHIT gene methylation and expression. Adequate intake of folate to maintain normal DNA methylation status is an effective way for cervical lesions prevention, and demethylation treatment may offer a new strategy for therapy of CC.

A metabolite profiling method for diagnosis of precancerous cervical lesions and HPV persistence

Aim: With the advent of rapid metabolic profiling techniques and of portable mass spectrometers we examined whether cells distinguished by their cytology and persistence of human papillomavirus infection, could be easily differentiated by their metabolite profile. Materials & methods: Direct injection electrospray mass spectrometry was used in a nontargeted double-blind experiment. Samples were collected from women diagnosed with one of two grades of cervical cytology and exhibiting either human papilloma virus persistence or clearance. Cell extracts were prepared using a DNA extraction procedure and the resulting supernatant, normally discarded, was analyzed. Data were interpreted using principal component analysis. Results: The results indicate strongly that a simple metabolite profiling method could be used to rapidly identify women at increased risk of cervical cancer.

Low folate levels are associated with methylation-mediated transcriptional repression of miR-203 and miR-375 during cervical carcinogenesis

The aim of the present study was to investigate the correlation between a lack of folic acid and the abnormal expression of microRNA (miR)-203 and miR-375 in cervical cancer. In total, 60 tissue samples of cervical intraepithelial neoplasia (CIN) or stage IA-IIA cervical cancer (study group), and 30 samples without soluble interleukin or malignancy (control group) were examined. The expression of miR-203 and miR-375 was detected using reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and the difference in expression levels was quantified using the 2^-ΔΔCq method. In addition, CaSki cervical cancer cells were cultured in vitro and treated with various concentrations of folic acid. The DNA methylation states of miR-203 and miR-375 were subsequently detected by methylation-specific PCR, and the expression levels were evaluated using RT-PCR. miR-203 and miR-375 were significantly downregulated in CIN and cervical cancer tissues, compared with the control group. There was a marked difference in terms of the expression levels of miR-375 between the two groups (P<0.05). In CaSki cells, as the concentration of folic acid increased, the positive rate of DNA methylation of miR-203 and miR-375 decreased, while the expression levels of miR-203 and miR-375 demonstrated a gradual increase, which indicated that the latter two parameters were negatively correlated (P<0.05). Compared with normal cervical tissue, the expression levels of miR-203 and miR-375 were downregulated in CIN and cervical cancer. Methylation of these two miRs was apparent in CaSki cells, and was associated with a lack of folic acid. Therefore, reduced levels of folic acid, leading to increased methylation of miR-203 and miR-375, may be significant events during cervical carcinogenesis.

DAPK1 Promoter Methylation and Cervical Cancer Risk: A Systematic Review and a Meta-Analysis

Objective

The Death-Associated Protein Kinase 1 (DAPK1) gene has been frequently investigated in cervical cancer (CC). The aim of the present study was to carry out a systematic review and a meta-analysis in order to evaluate DAPK1 promoter methylation as an epigenetic marker for CC risk.

Methods

A systematic literature search was carried out. The Cochrane software package Review Manager 5.2 was used. The fixed-effects or random-effects models, according to heterogeneity across studies, were used to calculate odds ratios (ORs) and 95% Confidence Intervals (CIs). Furthermore, subgroup analyses were conducted by histological type, assays used to evaluate DAPK1 promoter methylation, and control sample source.

Results

A total of 20 papers, published between 2001 and 2014, on 1929 samples, were included in the meta-analysis. DAPK1 promoter methylation was associated with an increased CC risk based on the random effects model (OR: 21.20; 95%CI = 11.14–40.35). Omitting the most heterogeneous study, the between study heterogeneity decreased and the association increased (OR: 24.13; 95% CI = 15.83–36.78). The association was also confirmed in all the subgroups analyses.

Conclusions

A significant strong association between DAPK1 promoter methylation and CC was shown and confirmed independently by histological tumor type, method used to evaluate methylation and source of control samples. Methylation markers may have value in early detection of CC precursor lesions, provide added reassurances of safety for women who are candidates for less frequent screens, and predict outcomes of women infected with human papilloma virus.