Methylomic analysis identifies frequent DNA methylation of zinc finger protein 582 (ZNF582) in cervical neoplasms

Genome-wide methylation profiling reveals Zinc finger protein 516 (ZNF516) and FK-506-binding protein 6 (FKBP6) promoters frequently methylated in cervical neoplasia, associated with HPV status and ethnicity in a Chilean population

Cervical cancer is a major health concern among women in Latin America due to its high incidence and mortality. Therefore, the discovery of molecular markers for cervical cancer screening and triage is imperative. The aim of this study was to use a genome wide DNA methylation approach to identify novel methylation biomarkers in cervical cancer. DNA from normal cervical mucosa and cervical cancer tissue samples from Chile was enriched with Methylated DNA Immunoprecipitation (MeDIP), hybridized to oligonucleotide methylation microarrays and analyzed with a stringent bioinformatics pipeline to identify differentially methylated regions (DMRs) as candidate biomarkers. Quantitative Methylation Specific PCR (qMSP) was used to study promoter methylation of candidate DMRs in clinical samples from two independent cohorts. HPV detection and genotyping were performed by Reverse Line Blot analysis. Bioinformatics analysis revealed GGTLA4, FKBP6, ZNF516, SAP130, and INTS1 to be differentially methylated in cancer and normal tissues in the Discovery cohort. In the Validation cohort FKBP6 promoter methylation had 73% sensitivity and 80% specificity (AUC = 0.80). ZNF516 promoter methylation was the best biomarker, with both sensitivity and specificity of 90% (AUC = 0.92), results subsequently corroborated in a Prevalence cohort. Together, ZNF516 and FKBP6 exhibited a sensitivity of 84% and specificity of 81%, when considering both cohorts. Our genome wide DNA methylation assessment approach (MeDIP-chip) successfully identified novel biomarkers that differentiate between cervical cancer and normal samples, after adjusting for age and HPV status. These biomarkers need to be further explored in case-control and prospective cohorts to validate them as cervical cancer biomarkers.

A minimal set of tissue-specific hypomethylated CpGs constitute epigenetic signatures of developmental programming

Background

Cell specific states of the chromatin are programmed during mammalian development. Dynamic DNA methylation across the developing embryo guides a program of repression, switching off genes in most cell types. Thus, the majority of the tissue specific differentially methylated sites (TS-DMS) must be un-methylated CpGs.

Methodology and Principal Findings

Comparison of expanded Methyl Sensitive Cut Counting data (eMSCC) among four tissues (liver, testes, brain and kidney) from three C57BL/6J mice, identified 138,052 differentially methylated sites of which 23,270 contain CpGs un-methylated in only one tissue (TS-DMS). Most of these CpGs were located in intergenic regions, outside of promoters, CpG islands or their shores, and up to 20% of them overlapped reported active enhancers. Indeed, tissue-specific enhancers were up to 30 fold enriched in TS-DMS. Testis showed the highest number of TS-DMS, but paradoxically their associated genes do not appear to be specific to the germ cell functions, but rather are involved in organism development. In the other tissues the differentially methylated genes are associated with tissue-specific physiological or anatomical functions. The identified sets of TS-DMS quantify epigenetic distances between tissues, generated during development. We applied this concept to measure the extent of reprogramming in the liver of mice exposed to in utero or early postnatal nutritional stress. Different protocols of food restriction reprogrammed the liver methylome in different but reproducible ways.

Conclusion and Significance

Thus, each identified set of differentially methylated sites constituted an epigenetic signature that traced the developmental programing or the early nutritional reprogramming of each exposed mouse. We propose that our approach has the potential to outline a number of disease-associated epigenetic states. The composition of differentially methylated CpGs may vary with each situation, behaving as a composite variable, which can be used as a pre-symptomatic marker for disease.

Genome-wide DNA methylation assay reveals novel candidate biomarker genes in cervical cancer

The oncogenic human papilloma viruses (HPVs) are associated with precancerous cervical lesions and development of cervical cancer. The DNA methylation signatures of the host genome in normal, precancerous and cervical cancer tissue may indicate tissue-specific perturbation in carcinogenesis. The aim of this study was to identify new candidate genes that are differentially methylated in squamous cell carcinoma compared with DNA samples from cervical intraepithelial neoplasia grade 3 (CIN3) and normal cervical scrapes. The Illumina Infinium HumanMethylation450 BeadChip method identifies genome-wide DNA methylation changes in CpG islands, CpG shores and shelves. Our findings showed an extensive differential methylation signature in cervical cancer compared with the CIN3 or normal cervical tissues. The identified candidate biomarker genes for cervical cancer represent several types of mechanisms in the cellular machinery that are epigenetically deregulated by hypermethylation, such as membrane receptors, intracellular signaling and gene transcription. The results also confirm extensive hypomethylation of genes in the immune system in cancer tissues. These insights into the functional role of DNA methylome alterations in cervical cancer could be clinically applicable in diagnostics and prognostics, and may guide the development of new epigenetic therapies.

DNA methylation of PAX1 as a biomarker for oral squamous cell carcinoma

OBJECTIVES

DNA methylation has been shown to be a promising cancer biomarker. The aim of this study was to evaluate DNA methylation of three transcription factors, sex-determining region Y-box 1 (SOX1), paired box gene 1 (PAX1), and zinc-finger 582 (ZNF582), in detecting oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

A case-control study was conducted at Taipei Medical University Hospital in Taiwan with 31 cases of various oral cavity squamous cell carcinomas and 40 controls. Questionnaire data assessing environmental exposure, such as alcohol consumption, cigarette smoking, and betel nut chewing, were obtained from each participant. DNA from oral swabs were analyzed for methylation using quantitative methylation polymerase chain reaction with TaqMan probes. Methylation status was determined using a methylation index.

RESULTS

Methylation levels of SOX1, PAX1, and ZNF582 were significantly higher in cancer patients (p = 0.02, p = 0.02, and p = 0.03, respectively). Patients with highly methylated SOX1, PAX1, and ZNF582 had an increased cancer risk with odds ratios (ORs) of 16.50 (95 % CI = 2.85-96.65), 60.57 (95 % CI = 5.85-629.94), and 5.07 (95 % CI = 1.08-23.76), respectively. Area under the curve (AUC) values were 0.85, 0.78, and 0.78 for PAX1, SOX1, and ZNF582, respectively. When stratified based on environmental exposure, the AUC of PAX1 methylation (PAX1 (m) ) was 0.94 in environmental exposure-naïve subjects and 0.85 for SOX1 methylation in subjects who chewed betel nut. In general, the sensitivity and specificity of PAX1 (m) were 87 and 80 % for OSCC detection. The sensitivity of PAX1 (m) in subjects who chewed betel nut was 83 %, with a specificity of 75 %.

CONCLUSIONS

Testing PAX1 DNA methylation using oral swabs is a promising method for oral cancer detection. Combined assessments regarding betel nut consumption and DNA methylation can improve OSCC screening.

CLINICAL RELEVANCE

The double E (environmental and epigenetic) assessment is a potential strategy in OSCC screening.