Telomere length in cervical exfoliated cells, interaction with HPV genotype, and cervical cancer occurrence among high-risk HPV-positive women

Role of telomere length in human carcinogenesis (Review)

Cancer is considered the most important clinical, social and economic issue regarding cause‑specific disability‑adjusted life years among all human pathologies. Exogenous, endogenous and individual factors, including genetic predisposition, participate in cancer triggering. Telomeres are specific DNA structures positioned at the end of chromosomes and consist of repetitive nucleotide sequences, which, together with shelterin proteins, facilitate the maintenance of chromosome stability, while protecting them from genomic erosion. Even though the connection between telomere status and carcinogenesis has been identified, the absence of a universal or even a cancer‑specific trend renders consent even more complex. It is indicative that both short and long telomere lengths have been associated with a high risk of cancer incidence. When evaluating risk associations between cancer and telomere length, a disparity appears to emerge. Even though shorter telomeres have been adopted as a marker of poorer health status and an older biological age, longer telomeres due to increased cell growth potential are associated with the acquirement of cancer‑initiating somatic mutations. Therefore, the present review aimed to comprehensively present the multifaceted pattern of telomere length and cancer incidence association.

Prognostic value of SOX9 in cervical cancer: Bioinformatics and experimental approaches

Among gynecological cancers, cervical cancer is a common malignancy and remains the leading cause of cancer-related death for women. However, the exact molecular pathogenesis of cervical cancer is not known. Hence, understanding the molecular mechanisms underlying cervical cancer pathogenesis will aid in the development of effective treatment modalities. In this research, we attempted to discern candidate biomarkers for cervical cancer by using multiple bioinformatics approaches. First, we performed differential expression analysis based on cervical squamous cell carcinoma and endocervical adenocarcinoma data from The Cancer Genome Atlas database, then used differentially expressed genes for weighted gene co-expression network construction to find the most relevant gene module for cervical cancer. Next, the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed on the module genes, followed by using protein–protein interaction network analysis and Cytoscape to find the key gene. Finally, we validated the key gene by using multiple online sites and experimental methods. Through weighted gene co-expression network analysis, we found the turquoise module was the highest correlated module with cervical cancer diagnosis. The biological process of the module genes focused on cell proliferation, cell adhesion, and protein binding processes, while the Kyoto Encyclopedia of Genes and Genomes pathway of the module significantly enriched pathways related to cancer and cell circle. Among the module genes, SOX9 was identified as the hub gene, and its expression was associated with cervical cancer prognosis. We found the expression of SOX9 correlates with cancer-associated fibroblast immune infiltration in immune cells by Timer2.0. Furthermore, cancer-associated fibroblast infiltration is linked to cervical cancer patients’ prognosis. Compared to those in normal adjacent, immunohistochemical and real-time quantitative polymerase chain reaction (qPCR) showed that the protein and mRNA expression of SOX9 in cervical cancer were higher. Therefore, the SOX9 gene acts as an oncogene in cervical cancer, interactive with immune infiltration of cancer-associated fibroblasts, thereby affecting the prognosis of patients with cervical cancer.

Knockdown of TRIM11 suppresses cell progression and apoptosis of cervical cancer cells via PI3K/AKT pathway

OBJECTIVE

To detect the expression pattern of TRIM11 in CC and to investigate the effect of TRIM11 knockdown on CC progression.

METHODS

First, the expression pattern and function of TRIM11 in CC were inferred by GEPIA database. The expression of TRIM11 in CC tissues and cells was verified by RT-qPCR and Western blot assays. TRIM11 shRNA was transfected into CC cells. The effect of TRIM11 knockdown on CC cell proliferation and cell apoptosis was assessed by CCK-8 assay, clone formation test and flow cytometry (FCM). Furthermore, the effect of TRIM11 knockdown on cell migration and invasion was measured by Transwell assay. The apoptosis-related proteins (Bax, Bcl-2 and Cleaved caspase 3) and PI3K/AKT pathway-related proteins (PI3K, p-PI3K, AKT and p-Akt) were examined by Western blot assay.

RESULTS

TRIM11 was found to be dramatically upregulated in CC tissues and cells. Besides this, TRIM11 was closely related to FIGO stage, infiltration depth and metastasis. Moreover, high expression of TRIM11 was found to be associated with poor prognosis of CC patients. Functional experiments showed that knockdown of TRIM11 obviously suppressed CC cell proliferation, migration and invasion, while accelerated cell apoptosis. In addition, the PI3K inhibitor (LY294002) was used to assess the connection between PI3K/AKT pathway and TRIM11 in CC cells. We found that TRIM11 overexpression suppressed the phosphorylation of PI3K and AKT in CC cells.

CONCLUSION

Hence, TRIM11 regulates CC cell progression by modulating PI3K/AKT pathway. The results suggested that TRIM11 might be a possible target for the diagnosis and prognosis of CC patients.

Telomere shortening in head and neck cancer: association between DNA demethylation and survival

A growing body of evidence indicates that telomere dysfunction is a biological marker of progression in several types of cancer. However, the association between head and neck squamous cell carcinoma (HNSCC) and telomere length (TL) remains unknown. We measured the absolute TL levels in a well-characterised dataset of 211 tumoral vs normal tissues obtained from the same patients by quantitative polymerase chain reaction assay. Normalised TL levels were significantly lower in tumour samples than in normal tissue (P < 0.001) and there was a positive correlation between tumour tissue and normal mucosal tissue (R² = 0.176, P < 0.001). We were able to distinguish two classes, one with a tumour/normal TL ratio ≤ 0.3 (38.4%), which showed clear telomere erosion, and the other with a tumour/normal TL ratio > 0.3 (61.6%), in which the TL was slightly shorter or longer than that in normal tissue. Notably, the tumour/normal TL ratio was correlated with the likelihood of disease recurrence (P = 0.002), the 5-hydroxymethylcytosine level (P = 0.043), and expression of the ten-eleven translocation (TET) gene (P = 0.043). Our findings show that TL shortening and subsequent low levels of 5-hydroxymethylcytosine and TET expression may contribute to development of HNSCC.

The Role of High-Risk Human Papillomavirus-Related Long Non-Coding RNAs in the Prognosis of Cervical Squamous Cell Carcinoma

Cervical cancer (CC) is a malignant tumor that could seriously endanger women's life and health, of which cervical squamous cell carcinoma (CESC) accounts for more than 80%. High-risk human papillomavirus (HR-HPV) infection is the primary cause of CC. The 5-year survival rate is low due to poor prognosis. We need to explore the pathogenesis of CC and seek effective biomarkers to improve prognosis. The purpose of this research is to construct an HR-HPV-related long non-coding RNA (lncRNA) signature for predicting the survival and finding the biomarkers related to CC prognosis. First, we downloaded the CESC data from The Cancer Genome Atlas (TCGA) database to find HR-HPV-related lncRNAs in CC. Then, the differentially expressed lncRNAs were analyzed by univariate and multivariate Cox regression. Six lncRNAs were found to be associated with the prognosis and can be used as independent prognostic factors. Next, based on these prognostic genes, we established a risk score model, which showed that patients with higher score had poorer prognosis and higher mortality. Moreover, the Kaplan-Meier curve of the model indicated that the model was statistically significant (p < 0.05). The survival-receiver operating characteristic curve showed that the model could also predict the survival of CC patients (the area under the curve, AUC = 0.65). More importantly, nomogram was drawn with clinical features and risk score, which verified the above conclusion, and its calibration curve and c-index index fully demonstrated that the prediction model could predict the progress of CC. We also validated the risk score model in head and neck cancer, and the results indicated that the model had obvious prognostic ability. Finally, we analyzed the correlation between clinical features and survival, and found that neoplasm cancer (p < 0.000) and risk score (p < 0.000) were independent prognostic factors for CC. In conclusion, the study established HR-HPV-related lncRNA signature, which provided a reliable prognostic tool, and was of great significance for finding the biomarkers related to HR-HPV infection in CC.

Telomere length in cervical exfoliated cells, interaction with HPV genotype, and cervical cancer occurrence among high-risk HPV-positive women

BACKGROUND

Although high-risk human papillomavirus (HR-HPV) infection is recognized as the main cause of cervical cancer, only a minority of HPV-infected women develop this malignancy. Increasing evidence suggests that alterations of telomere length might be implicated in carcinogenesis. However, the association between cervical cancer and telomere length remains unknown.

METHODS

This case-control study included 591 cervical cancer patients and 373 cancer-free controls, all of whom were infected with HR-HPV. Relative telomere length (RTL) in cervical cancer exfoliated cells was measured by quantitative PCR. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by logistic regression analysis.

RESULTS

HPV16, 18, 52, and 58 were common in both case and control groups. The proportion of HPV16 infection tended to increase across the quartiles of RTL (P_trend  < 0.001). There was no statistically significant association of RTL with tumor differentiation, histological type, and FIGO stage. After adjustment for age and HPV types, the lowest quartile of RTL presented a 49% lower risk (OR = 0.51, 95% CI: 0.35, 0.76; P < 0.001) than those with the highest quartile of RTL. There was also a dose-response relationship of shorter RTL on lower risk of cervical cancer (P_trend  < 0.001).

CONCLUSION

Shortened telomere length in cervical exfoliated cells was related to the lower risk of cervical cancer among HR-HPV-positive women, which might help to improve cervical cancer screening and surveillance. Further prospective studies with large sample should be designed to validate our preliminary findings, and evaluate the potential efficacy of telomere length for cervical cancer screening.