Simultaneous detection of human papillomavirus integration and c-MYC gene amplification in cervical lesions: an emerging marker for the risk to progression

Combined Effects of 2-Methoxyestradiol (Hypoxia-Inducible Factor 1α Inhibitor) and Dasatinib (A Second-Generation Tyrosine Kinase Inhibitor) on Chronic Myelocytic Leukemia Cells

Chronic myelocytic leukemia (CML) is a frequently encountered type of leukemia in China. Hypoxia-inducible factor 1 (HIF-1) serves as one of the most important factors of oxygen balance transcription. The activation of this gene mostly marks a poor outlook for cancer patients. To clarify the therapeutic effect of inhibiting this gene on CML, the present study is aimed at exploring the treatment effects of 2-methoxyestradiol (2-ME2), dasatinib alone, and combined both on K-562 cells and the possible mechanism of 2-ME2 in treating the disorder. The levels of HIF-1α, vascular endothelial growth factor (VEGF), and glutamate synthase 1 (GLU1) genes in K-562 cells were affected dose-dependently after 2-ME2 administration. 2-ME2 induced cell apoptosis by downregulating antiapoptotic protein expressions of Bcl-xl and Bcl-2. The therapeutic effect of single 2-ME2 was superior to single dasatinib, and the effect of combined therapy of both drugs produced better effectiveness than either of the single drug. Once the concentration of 2-ME2 exceeded 0.5 μM, downregulated C-myc gene expression could exert roles in anti-CML cell proliferation and inducing apoptosis. Dasatinib might participate in the inhibition of the C-myc pathway during this process whereas its effect remained not clear. Taken together, abnormal high expression of HIF-1α exerted an essential role in CML occurrence and development. Inhibition of this gene could markedly increase cell apoptosis in a dose-dependent fashion. Moreover, 2-ME2 could induce cell apoptosis by downregulating the C-myc gene and exert an apoptotic effect by downregulating Bcl-xl and Bcl-2 which act as antiapoptotic proteins.

Targeted Next Generation Sequencing for Human Papillomavirus Genotyping in Cervical Liquid-Based Cytology Samples

Simple Summary

Testing for Human Papillomavirus (HPV) is currently being implemented as part of cervical cancer (CC) screening in several countries. However, infections with all but one of the HPV types classified as possibly carcinogenic cannot be detected by the assays used for CC screening today. The aim of our study was to demonstrate the use of a targeted next generation sequencing (NGS) HPV panel for CC screening—both general practitioner-collected samples and self-samples. We here show that the targeted HPV panel can detect HPV with a sensitivity and specificity similar to commercial HPV assays, one of which is used for CC screening today. However, the targeted HPV panel possess several advantages compared to the screening assays, as it enables specific detection of all relevant HPV types and can identify viral integration, variants in the HPV genome, and dominant HPV types in multi-infected cases.

Abstract

At present, human papillomavirus (HPV) testing is replacing morphology-based cytology as the primary tool for cervical cancer screening in several countries. However, the HPV assays approved for screening lack detection for all but one of the possibly carcinogenic HPV types and do not genotype all included HPV types. This study demonstrates the use of a targeted HPV next generation sequencing (NGS) panel to detect and genotype all 25 carcinogenic, probably carcinogenic, and possibly carcinogenic HPV types as well as the low-risk types HPV6 and HPV11. The panel was validated using a cohort of 93 paired liquid-based cytology samples (general practitioner (GP)-collected cervical samples and cervico-vaginal self-samples (SS)). Overall, the targeted panel had a sensitivity (GP = 97.7%, SS = 92.1%) and specificity (GP = 98.0%, SS = 96.4%) similar to the commercial HPV assays, Cobas^® 4800 HPV DNA test (Roche) and CLART^® HPV4S assay (GENOMICA). Interestingly, of the samples that tested positive with the NGS panel, three (6.4%) of the GP-collected samples and four (9.1%) of the self-samples tested positive exclusively for HPV types only included in the NGS panel. Thus, targeted HPV sequencing has great potential to improve the HPV screening programs since, as shown here, it can identify additional HPV positive cases, cases with HPV integration, variants in the HPV genome, and which HPV type is dominant in multi-infected cases.

Unusual prevalence of high-risk genotypes of human papillomavirus in a group of women with neoplastic lesions and cervical cancer from Central Mexico

Human papillomavirus has been identified as a main etiological agent in the development of cervical cancer. HPV 16 and 18 have been reported the most widely prevalent genotypes worldwide. We conducted a study analyzing the prevalence of high and low risk human papillomavirus viral types in the Mexican state of Aguascalientes and neighboring cities in the states of Jalisco and Zacatecas in central Mexico. Specific viral genotype was determined by a PCR and hybridization-based detection test. The presence of 37 high- and low-risk HPV genotypes was evaluated in 883 female participants. Of these, 350 presented low-grade squamous intraepithelial lesions (LGSIL), 176 presented high-grade squamous intraepithelial lesions (HGSIL), 107 suffered from cervical cancer and 250 women with negative cytological report for intraepithelial lesion or malignancy (NILM). HPV 51 was the most prevalent genotype, followed by HPV 16: overall prevalence of HPV 51, including single infections and co-infections was 31.2% in women with LGSIL, whereas prevalence of HPV 16 was 25.1%. Among women with HGSIL, HPV 51 prevalence was 47.2% and HPV 16 was 30.1%. Prevalence of HPV 51 in women with cervical cancer was 49.5% and type 16 was 33.6%. Between single and co-infections, most co-infections were not associated with later stages of the disease, except 51/16 and some others. HPV 51 showed a significant correlation with the progression of the disease (OR = 10.81 for LGSIL, 19.38 for HGSIL and 22.95 for ICC), and when analyzing all other genotypes, five different groups depending on their correlation with all lesion grades were determined. According to our findings, HPV genotype 51 has a higher prevalence than HPV 16 and 18 in the Mexican state of Aguascalientes and neighboring cities in the states of Jalisco and Zacatecas in Central Mexico.

IFNα-Expressing Amniotic Fluid-Derived Mesenchymal Stem Cells Migrate to and Suppress HeLa Cell-Derived Tumors in a Mouse Model

Background

Immunotherapy for cervical cancer with type I interferon (IFN) is limited because of the cytotoxicity that accompanies the high doses that are administered. In this study, we investigated the utilization of amniotic fluid-derived mesenchymal stem cells (AF-MSCs) as a means for delivering IFNα to local tumor sites for the suppression of cervical cancer in a mouse model using HeLa cell xenografts.

Methods

The tumor tropism ability of AF-MSCs and AF-MSCs genetically modified to overexpress IFNα (IFNα-AF-MSCs) was examined through Transwell in vitro and through fluorescent images and immunohistochemistry in a mouse model. Tumor size and tumor apoptosis were observed to evaluate the efficacy of the targeting therapy. Mechanistically, tumor cell apoptosis was detected by cytometry and TUNEL, and oncogenic proteins c-Myc, p53, and Bcl-2 as well as microvessel density were detected by immunohistochemistry.

Results

In this model, intravenously injected AF-MSCs selectively migrated to the tumor sites, participated in tumor construction, and promoted tumor growth. After being genetically modified to overexpress IFNα, the IFNα-AF-MSCs maintained their tumor tropism but could significantly suppress tumor growth. The restrictive efficacy of IFNα-AF-MSCs was associated with the suppression of angiogenesis, inhibition of tumor cell proliferation, and induction of apoptosis in tumor cells. Neither AF-MSCs nor IFNα-AF-MSCs trigger tumor formation.

Conclusions

IFNα-AF-MSC-based therapy is feasible and shows potential for treating cervical cancer, suggesting that AF-MSCs may be promising vehicles for delivering targeted anticancer therapy.

Long-distance interaction of the integrated HPV fragment with MYC gene and 8q24.22 region upregulating the allele-specific MYC expression in HeLa cells

Human papillomavirus (HPV) infection is the most important risk factor for cervical cancer development. In HeLa cell line, the HPV viral genome is integrated at 8q24 in one allele of chromosome 8. It has been reported that the HPV fragment integrated in HeLa genome can cis‐activate the expression of proto‐oncogene MYC, which is located at 500 kb downstream of the integrated site. However, the underlying molecular mechanism of this regulation is unknown. A recent study reported that MYC was highly expressed exclusively from the HPV‐integrated haplotype, and a long‐range chromatin interaction between the integrated HPV fragment and MYC gene has been hypothesized. In this study, we provided the experimental evidences supporting this long‐range chromatin interaction in HeLa cells by using Chromosome Conformation Capture (3C) method. We found that the integrated HPV fragment, MYC and 8q24.22 was close to each other and might form a trimer in spatial location. When knocking out the integrated HPV fragment or 8q24.22 region from chromosome 8 by CRISPR/Cas9 system, the expression of MYC reduced dramatically in HeLa cells. Interestingly, decreased expression was only observed in three from eight cell clones, when only one 8q24.22 allele was knocked out. Functionally, HPV knockout caused senescence‐associated acidic β‐gal activity in HeLa cells. These data indicate a long‐distance interaction of the integrated HPV fragment with MYC gene and 8q24.22 region, providing an alternative mechanism relevant to the carcinogenicity of HPV integration.

What's new?

Infection with human papillomavirus (HPV) is a well‐established risk factor for cervical cancer. The mechanism by which HPV integration into the host genome influences cervical oncogenesis, however, is not fully understood. Using chromosome conformation capture, the authors of this study provide evidence for carcinogenic involvement of a long‐range chromatin interaction between integrated HPV fragments, the proto‐oncogene MYC, and the 8q24.22 chromosomal region in HeLa cells. Knock‐out of either the integrated HPV fragment or the 8q24.22 region in HeLa cells significantly reduced MYC expression. The findings offer an alternative explanation for the carcinogenic mechanism of HPV viral genome integration.

Unique DNA methylation signature in HPV-positive head and neck squamous cell carcinomas

BACKGROUND

Head and neck squamous cell carcinomas (HNSCCs) represent a heterogeneous group of cancers for which human papilloma virus (HPV) infection is an emerging risk factor. Previous studies showed promoter hypermethylation in HPV(+) oropharyngeal cancers, but only few consistent target genes have been so far described, and the evidence of a functional impact on gene expression is still limited.

METHODS

We performed global and stratified pooled analyses of epigenome-wide data in HNSCCs based on the Illumina HumanMethylation450 bead-array data in order to identify tissue-specific components and common viral epigenetic targets in HPV-associated tumours.

RESULTS

We identified novel differentially methylated CpGs and regions associated with viral infection that are independent of the anatomic site. In particular, most hypomethylated regions were characterized by a marked loss of CpG island boundaries, which showed significant correlations with expression of neighbouring genes. Moreover, a subset of only five CpGs in a few hypomethylated regions predicted HPV status with a high level of specificity in different cohorts. Finally, this signature was a better predictor of survival compared with HPV status determined by viral gene expression by RNA sequencing in The Cancer Genome Atlas cohort.

CONCLUSIONS

We identified a novel epigenetic signature of HPV infection in HNSCCs which is independent of the anatomic site, is functionally correlated with gene expression and may be leveraged for improved stratification of prognosis in HNSCCs.

Molecular approaches for HPV genotyping and HPV-DNA physical status

Persistent infection with high-risk human papillomavirus (HPV) genotypes is the leading cause of cervical cancer development. To this end several studies have focused on designing molecular assays for HPV genotyping, which are considered as the gold standard for the early diagnosis of HPV infection. Moreover, the tendency of HPV DNA to be integrated into the host chromosome is a determining event for cervical oncogenesis. Thus, the establishment of molecular techniques was promoted in order to investigate the physical status of the HPV DNA and the locus of viral insertion into the host chromosome. The molecular approaches that have been developed recently facilitate the collection of a wide spectrum of valuable information specific to each individual patient and therefore can significantly contribute to the establishment of a personalised prognosis, diagnosis and treatment of HPV-positive patients. The present review focuses on state of the art molecular assays for HPV detection and genotyping for intra-lesion analyses, it examines molecular approaches for the determination of HPV-DNA physical status and it discusses the criteria for selecting the most appropriate regions of viral DNA to be incorporated in HPV genotyping and in the determination of HPV-DNA physical status.

Determination of malignant potential of cervical intraepithelial neoplasia

Basic diagnostic procedures in cervical cancer screening are able to set the diagnosis but they do not provide any information about the biological nature and behavior of lesions. The causal link of HPV infection and cervical cancer and discoveries of complex interactions between host and HPV genome opened new possibilities in molecular diagnostics. HPV DNA analysis, determination of viral load, detection of E6 and E7 mRNA transcripts, identifying of methylation profiles, genomic changes, miRNAs, and telomerase activity should be the right choice for exact diagnostics and prediction of behavior of premalignant lesions of the cervix. These findings set a completely new light not only in diagnostic but also in management and treatment of cervical dysplasia and cervical cancer.