Downregulation of 5-hydroxymethylcytosine is associated with the progression of cervical intraepithelial neoplasia

Enhancing Cervical Cancer Screening: New Diagnostic Methodologies, Triage, and Risk Stratification in Prevention and Treatment

Human papillomavirus (HPV) is a well-established etiological factor in the development of precancerous cervical lesions and cervical cancer. This narrative review synthesizes current evidence on the global prevalence, genotype distribution, and pathophysiological mechanisms of HPV infection, emphasizing regional epidemiological variations that influence prevention and treatment strategies. Particular attention is given to high-risk HPV genotypes, their role in carcinogenesis, and the impact of co-infections and the cervicovaginal microbiota on infection persistence and disease progression. Advances in diagnostic methodologies, including E6/E7 oncoprotein detection, DNA methylation, and microRNA-based assays, are examined in the context of improving screening accuracy and early detection. Furthermore, the review explores the psychological implications of HPV diagnosis and underscores the importance of integrating psychosocial support into clinical management. Given the challenges associated with screening coverage, the potential of self-sampling techniques, particularly in resource-limited settings, is discussed as a means to enhance accessibility and participation in cervical cancer prevention programs. By providing a comprehensive overview of these interrelated factors, this review highlights the necessity of a multidisciplinary approach that integrates novel diagnostic strategies, targeted prevention efforts, and supportive care to mitigate the burden of HPV-associated diseases.

Inhibition of cytosine 5-hydroxymethylation during progression of cancer precursor lesions in the uterine cervix

Methylation and hydroxymethylation of cytosine moieties in CpG islands of specific genes are epigenetic processes shown to be involved in the development of cervical (pre)neoplastic lesions. We studied global (hydroxy)methylation during the subsequent steps in the carcinogenic process of the uterine cervix by using immunohistochemical protocols for the detection of 5-methylcytosine (5-mC) and 5-hydroxymethylcytosine (5-hmC) in paraffin-embedded tissues of the normal epithelia and (pre)malignant lesions. This approach allowed obtaining spatially resolved information of (epi)genetic alterations for individual cell populations in morphologically heterogeneous tissue samples. The normal ectocervical squamous epithelium showed a high degree of heterogeneity for both modifications, with a major positivity for 5-mC in the basal and parabasal layers in the ectocervical region, while 5-hmC immunostaining was even more restricted to the cells in the basal layer. Immature squamous metaplasia, characterized by expression of SOX17, surprisingly showed a decrease of 5-hmC in the basal compartments and an increase in the more superficial layers of the epithelium. The normal endocervical glandular epithelium showed a strong immunostaining reactivity for both modifications. At the squamocolumnar junctions, a specific 5-hmC pattern was observed in the squamous epithelium, resembling that of metaplasia, with the typical weak to negative reaction for 5-hmC in the basal cell compartment. The reserve cells underlying the glandular epithelium were also largely negative for 5-hmC but showed immunostaining for 5-mC. While the overall methylation status remained relatively constant, about 20% of the high-grade squamous lesions showed a very low immunostaining reactivity for 5-hmC. The (pre)malignant glandular lesions, including adenocarcinoma in situ (AIS) and adenocarcinoma showed a progressive decrease of hydroxymethylation with advancement of the lesion, resulting in cases with regions that were negative for 5-hmC immunostaining. These data indicate that inhibition of demethylation, which normally follows cytosine hydroxymethylation, is an important epigenetic switch in the development of cervical cancer.

A paradigm for post-embryonic Oct4 re-expression: E7-induced hydroxymethylation regulates Oct4 expression in cervical cancer

The Octamer-binding transcription factor-4 (Oct4) is upregulated in different malignancies, yet a paradigm for mechanisms of Oct4 post-embryonic re-expression is inadequately understood. In cervical cancer, Oct4 expression is higher in human papillomavirus (HPV)-related than HPV-unrelated cervical cancers and this upregulation correlates with the expression of the E7 oncogene. We have reported that E7 affects the Oct4-transcriptional output and Oct4-related phenotypes in cervical cancer, however, the underlying mechanism remains elusive. Here, we characterize the Oct4-protein interactions in cervical cancer cells via computational analyses and Mass Spectrometry and reveal that Methyl-binding proteins (MBD2 and MBD3), are determinants of Oct4-driven transcription. E7 triggers MBD2 downregulation and TET1 upregulation, thereby disrupting the methylation status of the Oct4 gene. This coincides with an increase in the total DNA hydroxymethylation leading to the re-expression of Oct4 in cervical cancer and likely affecting broader transcriptional patterns. Our findings reveal a previously unreported mechanism by which the E7 oncogene can regulate Oct4 re-expression and global transcriptional patterns by increasing DNA hydroxymethylation and lowering the barrier to cellular plasticity during carcinogenesis.

The deficiency of 5-methylcytosine (5mC) and its ramification in the occurrence and prognosis of colon cancer

The incidence and mortality of colon cancer are increasing, and effective biomarkers for its diagnosis are limited. 5-methylcytosine (5mC), a vital DNA methylation marker, plays important roles in gene expression, genomic imprinting, and transposon inhibition. This study aimed to identify the predictors of colon cancer prognosis and lay the foundation for research on therapeutic targets by detecting the levels of 5mC, 5-hydroxymethylcytosine (5hmC), 5-formyl cytosine (5fC), and 5-carboxylcytosine (5caC) in colon cancer and adjacent non-tumor tissues. A tissue microarray including 100 colon cancer tissue samples and 60 adjacent non-tumor tissue samples was used. The expression levels of 5mC and its ramifications were assessed by immunohistochemistry. According to the expression levels, patients were divided into moderately positive and strongly positive groups, and the correlation between clinicopathological characteristics and methylation marks was assessed using 2-sided chi-square tests. The prognostic values of 5mC, 5hmC, 5fC, and 5caC were tested using Kaplan-Meier analyses. Compared with adjacent non-tumor tissues, the overall levels of DNA methylation were lower in colon carcinoma lesions. However, the clinical parameters were not significantly associated with these methylation markers, except for 5hmC, which was associated with the age of cancer patients (P value = .043). Kaplan-Meier analysis disclosed that moderate positive group had a significantly shorter disease specific survival than strong positive group for patients with different levels of 5mC (65.2 vs 95.2 months, P = .014) and 5hmC (71.2 vs 97.5 months, P = .045). 5mC and its ramifications (5hmC, 5fC, and 5caC) can serve as biomarkers for colon cancer. 5mC and 5hmC are stable predictors and therapeutic targets in colon cancer. However, further understanding of its function will help to reveal the complex tumorigenic process and identify new therapeutic strategies.

Impact of antigen retrieval protocols on the immunohistochemical detection of epigenetic DNA modifications

This study compares three different pretreatment protocols for the immunohistochemical detection of 5-methylcytosine (5-mC) and 5-hydroxymethylcytosine (5-hmC) in nuclear DNA. The human biological samples analyzed included formalin-fixed and paraffin-embedded (FFPE) normal squamous epithelium, ethanol-fixed cultured cells, and metaphase chromosomes. The antigen retrieval methods included low pH Citrate and high pH Tris-ethylenediaminetetraacetic acid (EDTA) protocols, as well as a method using Pepsin pretreatment combined with HCl for DNA denaturation. A gradual increase in the detection levels of 5-mC and 5-hmC was observed when going from Citrate via Tris/EDTA to Pepsin/HCl retrieval. While the Citrate retrieval protocol was the least efficient for the detection of 5-mC and 5-hmC, it did preserve nuclear morphology and enabled visualization of differences in intra- and internuclear distribution patterns in tissue and cell culture samples by single- and double-fluorescence detection. Quantification of (hydroxy)methylation levels in FFPE material demonstrated a significant heterogeneity and differences in 5-mC and 5-hmC levels within and between nuclei in the different compartments of normal squamous epithelium. It was concluded that immunohistochemical detection of 5-mC and 5-hmC enables the correlation of these DNA modifications with histomorphological features in heterogeneous tissues, but this is influenced by different pretreatment protocols that must be carefully chosen to allow an appropriate interpretation of these epigenetic switches.

Phototheranostics of Cervical Neoplasms with Chlorin e6 Photosensitizer

Simple Summary

Neoplasms of the cervix are the most common types of oncological pathology. Photodynamic therapy with intravenous administration of the photosensitizer chlorin e6 shows high efficiency in the treatment of precancerous lesions of the cervix with complete eradication of the human papillomavirus. The treatment method can reduce deaths from cervical cancer and preserve fertility in patients. Spectral and video fluorescence diagnostics allows intraoperatively assessing the degree of photosensitizer accumulation and photobleaching and visualizing the boundaries of pathologically altered tissues.

Abstract

(1) Purpose: Improving the treatment effectiveness of intraepithelial neoplasia of the cervix associated with human papillomavirus infection, based on the application of the method of photodynamic therapy with simultaneous laser excitation of fluorescence to clarify the boundaries of cervical neoplasms. (2) Methods: Examination and treatment of 52 patients aged 22 to 53 years with morphologically and cytologically confirmed mild to severe intraepithelial cervix neoplasia, preinvasive, micro-invasive, and squamous cell cervix carcinoma. All patients were carriers of human papillomavirus infection. The patients underwent photodynamic therapy with simultaneous laser excitation of fluorescence. The combined use of video and spectral fluorescence diagnostics for cervical neoplasms made it possible to control the photodynamic therapy process at all stages of the procedure. Evaluation of the photodynamic therapy of intraepithelial cervical neoplasms was carried out with colposcopic examination, cytological conclusion, and morphological verification of the biopsy material after the photodynamic therapy course. The success of human papillomavirus therapy was assessed based on the results of the polymerase chain reaction. (3) Results. The possibility of simultaneous spectral fluorescence diagnostics and photodynamic therapy using a laser source with a wavelength of 660 nm has been established, making it possible to assess the fluorescence index in real-time and control the photobleaching of photosensitizers in the irradiated area. The treatment of all 52 patients was successful after the first photodynamic therapy procedure. According to the PCR test of the discharge from the cervical canal, the previously identified HPV types were not observed in 48 patients. Previously identified HPV types were absent after repeated PDT in four patients (CIN III (n = 2), CIS (n = 2)). In 80.8% of patients, regression of the lesion was noted. (4) Conclusions. The high efficiency of photodynamic therapy with intravenous photosensitizer administration of chlorin e6 has been demonstrated both in relation to eradication therapy of human papillomavirus and in relation to the treatment of intraepithelial lesions of the cervix.