Identification of pivotal cellular factors involved in HPV-induced dysplastic and neoplastic cervical pathologies

Oncogenic role of ALX3 in cervical cancer cells through KDM2B-mediated histone demethylation of CDC25A

Background

Cell division cycle 25A (CDC25A) is a well-recognized regulator of cell cycle progression and is involved in cancer development. This work focused on the function of CDC25A in cervical cancer cell growth and the molecules involved.

Methods

A GEO dataset GSE63514 comprising data of cervical squamous cell carcinoma (CSCC) tissues was used to screen the aberrantly expressed genes in cervical cancer. The CDC25A expression in cancer and normal tissues was predicted in the GEPIA database and that in CSCC and normal cells was determined by RT-qPCR and western blot assays. Downregulation of CDC25A was introduced in CSCC cells to explore its function in cell growth and the cell cycle progression. The potential regulators of CDC25A activity and the possible involved signaling were explored.

Results

CDC25A was predicted to be overexpressed in CSCC, and high expression of CDC25A was observed in CSCC cells. Downregulation of CDC25A in ME180 and C33A cells reduced cell proliferation and blocked cell cycle progression, and it increased cell apoptosis. ALX3 was a positive regulator of CDC25A through transcription promotion. It recruited a histone demethylase, lysine demethylase 2B (KDM2B), to the CDC25A promoter, which enhanced CDC25A expression through demethylation of H3k4me3. Overexpression of ALX3 in cells blocked the inhibitory effects of CDC25A silencing. CDC25A was found as a positive regulator of the PI3K/Akt signaling pathway.

Conclusion

This study suggested that the ALX3 increased CDC25A expression through KDM2B-mediated demethylation of H3K4me3, which induced proliferation and cell cycle progression of cervical cancer cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08552-7.

Identification and validation of a six-gene signature associated with glycolysis to predict the prognosis of patients with cervical cancer

BACKGROUND

Cervical cancer (CC) is one of the most common gynaecological cancers. The gene signature is believed to be reliable for predicting cancer patient survival. However, there is no relevant study on the relationship between the glycolysis-related gene (GRG) signature and overall survival (OS) of patients with CC.

METHODS

We extracted the mRNA expression profiles of 306 tumour and 13 normal tissues from the University of California Santa Cruz (UCSC) Database. Then, we screened out differentially expressed glycolysis-related genes (DEGRGs) among these mRNAs. All patients were randomly divided into training cohort and validation cohort according to the ratio of 7: 3. Next, univariate and multivariate Cox regression analyses were carried out to select the GRG with predictive ability for the prognosis of the training cohort. Additionally, risk score model was constructed and validated it in the validation cohort.

RESULTS

Six mRNAs were obtained that were associated with patient survival. The filtered mRNAs were classified into the protective type (GOT1) and the risk type (HSPA5, ANGPTL4, PFKM, IER3 and PFKFB4). Additionally, by constructing the prognostic risk score model, we found that the OS of the high-risk group was notably poorer, which showed good predictive ability both in training cohort and validation cohort. And the six-gene signature is a prognostic indicator independent of clinicopathological features. Through the verification of PCR, the results showed that compared with the normal cervial tissuses, the expression level of six mRNAs were significantly higher in the CC tissue, which was consistent with our findings.

CONCLUSIONS

We constructed a glycolysis-related six-gene signature to predict the prognosis of patients with CC using bioinformatics methods. We provide a thorough comprehension of the effect of glycolysis in patients with CC and provide new targets and ideas for individualized treatment.

Aberrant localization of signaling proteins in skin cancer: Implications for treatment

Aberrant subcellular localization of signaling proteins can provide cancer cells with advantages such as resistance to apoptotic cell death, increased invasiveness and more rapid proliferation. Nuclear to cytoplasmic shifts in tumor-promoting proteins can lead to worse patient outcomes, providing opportunities to target cancer-specific processes. Herein, we review the significance of dysregulated protein localization with a focus on skin cancer. Altered localization of signaling proteins controlling cell cycle progression or cell death is a common feature of cancer. In some instances, aberrant subcellular localization results in an acquired prosurvival function. Taking advantage of this knowledge reveals novel targets useful in the development of cancer therapeutics.

The lysine acetyltransferase GCN5 contributes to human papillomavirus oncoprotein E7-induced cell proliferation via up-regulating E2F1

General control nondepressible 5 (GCN5), the first identified transcription-related lysine acetyltransferase (KAT), is an important catalytic component of a transcriptional regulatory SAGA (Spt-Ada-GCN5-Acetyltransferase) and ATAC (ADA2A-containing) complex. While GCN5 has been implicated in cancer development, its role in cervical cancer is not known. The human papillomavirus (HPV) oncoprotein E7 abrogates the G1 cell cycle checkpoint and induces genomic instability, which plays a central role in cervical carcinogenesis. In this study, we observed that GCN5 was up-regulated in HPV E7-expressing cells, knockdown of GCN5 inhibited cell cycle progression and DNA synthesis in HPV E7-expressing cells. Notably, GCN5 knockdown reduced the steady-state levels of transcription factor E2F1. Depletion of E2F1 caused G1 arrest while overexpression of E2F1 rescued the inhibitory effects of GCN5 knockdown on G1/S progression in HPV E7-expressing cells. Results from chromatin immunoprecipitation (ChIP) assays demonstrated that GCN5 bound to the E2F1 promoter and increased the extent of histone acetylation within these regions. GCN5 also acetylated c-Myc and increased its ability to bind to the E2F1 promoter. Knockdown of c-Myc reduced the steady-state levels of E2F1 and caused G1 arrest. These results revealed a novel mechanism of E7 function whereby elevated GCN5 acetylates histones and c-Myc to regulate E2F1 expression and cell cycle progression.

Human papillomavirus induced transformation in cervical and head and neck cancers

Human papillomavirus (HPV) is one of the most widely publicized and researched pathogenic DNA viruses. For decades, HPV research has focused on transforming viral activities in cervical cancer. During the past 15 years, however, HPV has also emerged as a major etiological agent in cancers of the head and neck, in particular squamous cell carcinoma. Even with significant strides achieved towards the screening and treatment of cervical cancer, and preventive vaccines, cervical cancer remains the leading cause of cancer-associated deaths for women in developing countries. Furthermore, routine screens are not available for those at risk of head and neck cancer. The current expectation is that HPV vaccination will prevent not only cervical, but also head and neck cancers. In order to determine if previous cervical cancer models for HPV infection and transformation are directly applicable to head and neck cancer, clinical and molecular disease aspects must be carefully compared. In this review, we briefly discuss the cervical and head and neck cancer literature to highlight clinical and genomic commonalities. Differences in prognosis, staging and treatment, as well as comparisons of mutational profiles, viral integration patterns, and alterations in gene expression will be addressed.