microRNAs' differential regulations mediate the progress of Human Papillomavirus (HPV)-induced Cervical Intraepithelial Neoplasia (CIN)

Sequential gene expression analysis of cervical malignant transformation identifies RFC4 as a novel diagnostic and prognostic biomarker

BACKGROUND

Cervical squamous cell carcinoma (SCC) is known to arise through increasingly higher-grade squamous intraepithelial lesions (SILs) or cervical intraepithelial neoplasias (CINs). This study aimed to describe sequential molecular changes and identify biomarkers in cervical malignant transformation.

METHODS

Multidimensional data from five publicly available microarray and TCGA-CESC datasets were analyzed. Immunohistochemistry was carried out on 354 cervical tissues (42 normal, 62 CIN1, 26 CIN2, 47 CIN3, and 177 SCC) to determine the potential diagnostic and prognostic value of identified biomarkers.

RESULTS

We demonstrated that normal epithelium and SILs presented higher molecular homogeneity than SCC. Genes in the region (e.g., 3q, 12q13) with copy number alteration or HPV integration were more likely to lose or gain expression. The IL-17 signaling pathway was enriched throughout disease progression with downregulation of IL17C and decreased Th17 cells at late stage. Furthermore, we identified AURKA, TOP2A, RFC4, and CEP55 as potential causative genes gradually upregulated during the normal-SILs-SCC transition. For detecting high-grade SIL (HSIL), TOP2A and RFC4 showed balanced sensitivity (both 88.2%) and specificity (87.1 and 90.1%), with high AUC (0.88 and 0.89). They had equivalent diagnostic performance alone to the combination of p16^INK4a and Ki-67. Meanwhile, increased expression of RFC4 significantly and independently predicted favorable outcomes in multi-institutional cohorts of SCC patients.

CONCLUSIONS

Our comprehensive study of gene expression profiling has identified dysregulated genes and biological processes during cervical carcinogenesis. RFC4 is proposed as a novel surrogate biomarker for determining HSIL and HSIL+, and an independent prognostic biomarker for SCC.

The E6 and E7 proteins of beta3 human papillomavirus 49 can deregulate both cellular and extracellular vesicles-carried microRNAs

BACKGROUND

The β3 human papillomavirus (HPV)49 induces immortalization of primary keratinocytes through the action of E6 and E7 oncoproteins with an efficiency similar to alpha high risk (HR)-HPV16. Since HR-HPV oncoproteins are known to alter microRNA (miRNA) expression and extracellular vesicle (EV) production, we investigated the impact of HPV49 E6 and E7 proteins on miRNA profile and EV expression, and their involvement in the control of cell proliferation.

METHODS

The miRNA expression was evaluated by a miRNA array and validated by RT-qPCR in primary human keratinocytes immortalized by β3 HPV49 (K49) or α9 HR-HPV16 (K16), and in EVs from K49 and K16. The modulation of miRNA target proteins was investigated by immunoblotting analyses.

RESULTS

By comparing miRNA expression in K49 and K16 and the derived EVs, six miRNAs involved in HPV tumorigenesis were selected and validated. MiR-19a and -99a were found to be upregulated and miR-34a downregulated in both cell lines; miR-17 and -590-5p were upregulated in K49 and downmodulated in K16; miR-21 was downregulated only in K16. As for EV-carried miRNAs, the expression of miR-17, -19a, -21 and -99a was decreased and miR-34a was increased in K49 EVs. In K16 EVs, we revealed the same modulation of miR-19a, -34a, and -99a observed in producing cells, while miR-21 was upregulated. Cyclin D1, a common target of the selected miRNAs, was downmodulated in both cell lines, whereas cyclin-dependent kinase 4 was down-modulated in K49 but upregulated in K16.

CONCLUSION

These data suggest that E6 and E7 proteins of β3 HPV49 and α9 HR-HPV16 affect key factors of cell cycle control by indirect mechanisms based on miRNA modulation.

When Viruses Cross Developmental Pathways

Aberrant regulation of developmental pathways plays a key role in tumorigenesis. Tumor cells differ from normal cells in their sustained proliferation, replicative immortality, resistance to cell death and growth inhibition, angiogenesis, and metastatic behavior. Often they acquire these features as a consequence of dysregulated Hedgehog, Notch, or WNT signaling pathways. Human tumor viruses affect the cancer cell hallmarks by encoding oncogenic proteins, and/or by modifying the microenvironment, as well as by conveying genomic instability to accelerate cancer development. In addition, viral immune evasion mechanisms may compromise developmental pathways to accelerate tumor growth. Viruses achieve this by influencing both coding and non-coding gene regulatory pathways. Elucidating how oncogenic viruses intersect with and modulate developmental pathways is crucial to understanding viral tumorigenesis. Many currently available antiviral therapies target viral lytic cycle replication but with low efficacy and severe side effects. A greater understanding of the cross-signaling between oncogenic viruses and developmental pathways will improve the efficacy of next-generation inhibitors and pave the way to more targeted antiviral therapies.

MiR-25 and KLF4 relationship has early prognostic significance in the development of cervical cancer

Cervical squamous cell carcinoma (SCC) is one of the common cancer types among women. MicroRNAs (miRNAs) are small non-coding RNAs that play an important role in the formation and development of many cancer types by regulating expression of their targets. While many studies have investigated the relationship between miRNAs and cervical cancer, no robust miRNA biomarkers have been defined yet for diagnosis of cervical lesions. In this study, we performed a statistical meta-analysis to identify miRNAs and a class compassion analysis to evaluate mRNAs with the power to discriminate between normal, intraepithelial lesions and invasive cancer samples. Differentially expressed (DE) mRNAs were compared with the targets of meta-miRNAs. After bioinfomatics analysis and qRT-PCR validations with cytology samples and FFPE tissues, we defined miR-25 and its target KLF4 (Kruppel-like factor 4) as candidate biomarkers for in vitro studies. Our results showed that miR-25 expression was significantly higher in precancerous lesions and invasive carcinoma while presenting consistent expression patterns in both cytological and FFPE tissue samples. In line with this, its direct target KLF4 expression decreased in precancerous lesions in cytological samples and also in the invasive cancer group in FFPE tissues. Furthermore, in vitro studies showed that mir-25 inhibition decreased proliferation and motility of HeLa cells and promoted an increase in the protein level of KLF4. We conclude that inhibition of miR-25 may upregulate KLF4 expression and regulate cell proliferation and motility in cervical cancer.

Genome-wide microRNA analysis of HPV-positive self-samples yields novel triage markers for early detection of cervical cancer

Offering self‐sampling for HPV testing improves the effectiveness of current cervical screening programs by increasing population coverage. Molecular markers directly applicable on self‐samples are needed to stratify HPV‐positive women at risk of cervical cancer (so‐called triage) and to avoid over‐referral and overtreatment. Deregulated microRNAs (miRNAs) have been implicated in the development of cervical cancer, and represent potential triage markers. However, it is unknown whether deregulated miRNA expression is reflected in self‐samples. Our study is the first to establish genome‐wide miRNA profiles in HPV‐positive self‐samples to identify miRNAs that can predict the presence of CIN3 and cervical cancer in self‐samples. Small RNA sequencing (sRNA‐Seq) was conducted to determine genome‐wide miRNA expression profiles in 74 HPV‐positive self‐samples of women with and without cervical precancer (CIN3). The optimal miRNA marker panel for CIN3 detection was determined by GRridge, a penalized method on logistic regression. Six miRNAs were validated by qPCR in 191 independent HPV‐positive self‐samples. Classification of sRNA‐Seq data yielded a 9‐miRNA marker panel with a combined area under the curve (AUC) of 0.89 for CIN3 detection. Validation by qPCR resulted in a combined AUC of 0.78 for CIN3+ detection. Our study shows that deregulated miRNA expression associated with CIN3 and cervical cancer development can be detected by sRNA‐Seq in HPV‐positive self‐samples. Validation by qPCR indicates that miRNA expression analysis offers a promising novel molecular triage strategy for CIN3 and cervical cancer detection applicable to self‐samples.

What's new?

MicroRNAs (miRNAs) are suspected of playing a role in cervical cancer development. They are also potential markers for the identification of human papillomavirus (HPV)‐infected women who are at risk of cervical cancer. Here, using small RNA sequencing of HPV‐positive self‐samples from women with and without cervical precancer (CIN3), the authors identify a miRNA signature consisting of multiple miRNAs that is strongly predictive of CIN3. Validation of this signature by qPCR revealed a good clinical performance for CIN3+ detection. The findings suggest that miRNA analysis is an effective means of CIN3+ prediction in HPV‐positive self‐samples obtained for cervical cancer screening.

Systematic assessment of cervical cancer initiation and progression uncovers genetic panels for deep learning-based early diagnosis and proposes novel diagnostic and prognostic biomarkers

Although many outstanding achievements in the management of cervical cancer (CxCa) have obtained, it still imposes a major burden which has prompted scientists to discover and validate new CxCa biomarkers to improve the diagnostic and prognostic assessment of CxCa. In this study, eight different gene expression data sets containing 202 cancer, 115 cervical intraepithelial neoplasia (CIN), and 105 normal samples were utilized for an integrative systems biology assessment in a multi-stage carcinogenesis manner. Deep learning-based diagnostic models were established based on the genetic panels of intrinsic genes of cervical carcinogenesis as well as on the unbiased variable selection approach. Survival analysis was also conducted to explore the potential biomarker candidates for prognostic assessment. Our results showed that cell cycle, RNA transport, mRNA surveillance, and one carbon pool by folate were the key regulatory mechanisms involved in the initiation, progression, and metastasis of CxCa. Various genetic panels combined with machine learning algorithms successfully differentiated CxCa from CIN and normalcy in cross-study normalized data sets. In particular, the 168-gene deep learning model for the differentiation of cancer from normalcy achieved an externally validated accuracy of 97.96% (99.01% sensitivity and 95.65% specificity). Survival analysis revealed that ZNF281 and EPHB6 were the two most promising prognostic genetic markers for CxCa among others. Our findings open new opportunities to enhance current understanding of the characteristics of CxCa pathobiology. In addition, the combination of transcriptomics-based signatures and deep learning classification may become an important approach to improve CxCa diagnosis and management in clinical practice.

MicroRNA-466 with tumor markers for cervical cancer screening

Cervical cancer is the second most common cancer in women in the world. In this study, we explore tumor markers and microRNA-466 combination for cervical cancer screening. Tumor markers were measured by the methods of electro-chemiluminescent immunoassay and enzyme immunoassay. The microRNA-466 was performed by quantitative real-time polymerase chain reaction. Among normal group, hyperplasia group and cancer group, the CEA expression levels were 2.26 ng/ml, 3.85 ng/ml and 16.08 ng/ml, respectively. While the CA125 expression levels were 13.61 u/ml, 27.32 u/ml and 44.93 u/ml, respectively. The SCCA expression levels were 13.61 ng/ml, 27.32 ng/ml and 44.93 ng/ml, respectively. The expression levels of tumor markers were all gradually increased with the development of cervical lesions. The expression levels of microRNA-466 in cervical cancers (0.62) were greater than that in normal (0.076) and hyperplasia (0.24). The expression of microRNA-466 was correlated with lymphnode metastasis (P=0.000). There is a lower overall survival rate of patient with large tumor or lymphnode metastasis. Thus, the combination of tumor markers and microRNA-466 can be useful for early detection of cervical cancer and indicators for advanced stage and prognosis of the disease.

MicroRNA-326 suppresses the proliferation, migration and invasion of cervical cancer cells by targeting ELK1

Although microRNAs (miRNAs or miRs) are able to function as oncogenes or tumor suppressors, the role of miR-326 in regulating human cervical cancer cells remains unclear. In the present study, the expression of miR-326 was identified to be downregulated in cervical cancer cell lines and primary tumor samples, and the overexpression of miR-326 decreased cell proliferation, migration and invasion in cervical cell lines. Bioinformatics prediction and experimental validation results revealed that the function of miR-326 was achieved by targeting and repressing ETS domain-containing protein Elk-1 (ELK1) expression. ELK1 was targeted directly by miR-326, which was downregulated in human cervical cancer tissues compared with that in adjacent normal tissues. The results of the present study suggest that miR-326, a potential tumor suppressor, may be used in the treatment of cervical cancer.

A New MicroRNA Expression Signature for Cervical Cancer

BACKGROUND

Cervical cancer is the second most common cancer among women worldwide. The potential of microRNAs as novel biomarkers in cervical cancer is growing.

OBJECTIVES

In this study, we investigated the functions and targets of miR-466 in cervical cancer tissues.

METHODS

Fresh cervical tissues were obtained from 157 patients with cervical cancer, cervical intraepithelial neoplasia (CIN), and healthy controls, and the tissues were immediately frozen in liquid nitrogen until use. The RNA was extracted and quantitative real-time polymerase chain reaction (PCR) was performed.

RESULTS

A total of 157 participants were summarized, including 56 patients with cervical cancer, 60 patients with CIN, and 49 healthy controls. The expression levels of miR-466 in cervical cancers (0.68) were higher than that in healthy controls (0.082) (P < 0.01). The average fold changes of miR-466 in the patients with CIN group and people group were 0.28 and 0.082, respectively (P < 0.01). It was a statistically significant difference in patients with lymph node involvement (P = 0.022). However, the expression of miR-466 was not correlated with International Federation of Gynecology and Obstetrics stages, tumor size, or vascular invasion (P = 0.506, P = 0.667, and P = 0.108, respectively).

CONCLUSIONS

Our results indicate that the aberrant expression of miR-466 is closely associated with the occurrence and development of cervical cancer.

miR-375 Affects the Proliferation, Invasion, and Apoptosis of HPV16-Positive Human Cervical Cancer Cells by Targeting IGF-1R

OBJECTIVE

The aim of this study was to examine the relationship between miR-375 expression and the proliferation, apoptosis, and migration of cervical cancer cells. To further explore the potential target gene of miR-375, insulin-like growth factor 1 receptor (IGF-1R) was detected in miR-375 overexpressed and inhibited cervical cancer cells, which clarified the potential mechanism of miR-375 in the growth and development of cervical cancer.

METHODS

In a cervical cancer cell line (Caski), miR-375 overexpression and knockdown were achieved by transfection with a synthetic miR-375 mimic or miR-375-targeting inhibitor oligonucleotides, respectively, using siRNA-Mate transfection reagents. Real-time Polymerase Chain Reaction was performed to detect the expression level of miR-375. The functional effects of miR-375 on cell proliferation, migration, and apoptosis were evaluated using a Cell Counting Kit (CCK-8) and through scratch wound tests and apoptosis assays, respectively. Western blotting was performed to detect the expression level of the IGF-1R protein.

RESULT

Transfection with the miR-375 mimic significantly upregulated the expression of miR-375 by approximately 7.76-fold (P < 0.05), reduced cell proliferation and migration (P < 0.05), increased apoptosis (P < 0.05), and decreased the expression of the IGF-1R protein by 24.73% (P < 0.05) compared with the negative control. In contrast, transfection of the miR-375 inhibitor decreased the expression of miR-375 by 14.39% (P < 0.05), significantly increased cell proliferation and migration (P < 0.05), significantly reduced the cell apoptosis (P < 0.05), and upregulated the expression of the IGF-1R protein by 2.29-fold (P < 0.05). The cells transfected with the negative control showed no significant changes compared with the blank control for each parameter (P > 0.05).

CONCLUSIONS

miR-375 plays an important role in the tumorigenesis and development of cervical cancer. IGF-1R might represent a target gene of miR-375 in cervical cancer.