Circular RNAs in endometrial carcinoma (Review)

Circular RNA_015343 sponges microRNA-25 to regulate viability, proliferation, and milk fat synthesis of ovine mammary epithelial cells via INSIG1

In our previous study, circ_015343 was found to inhibit the viability and proliferation of ovine mammary epithelial cells (OMECs) and the expression levels of milk fat synthesis marker genes, but the regulatory mechanism underlying the processes is still unclear. Accordingly in this study, the target relationships between circ_015343 with miR-25 and between miR-25 with insulin induced gene 1 (INSIG1) were verified, and the functions of miR-25 and INSIG1 were investigated in OMECs. The dual-luciferase reporter assay revealed that miR-25 mimic remarkably decreased the luciferase activity of circ_015343 in HEK293T cells cotransfected with a wild-type vector, while it did not change the activity of circ_015343 in HEK293T cells cotransfected with a mutant vector. These suggest that cic_015343 can adsorb and bind miR-25. The miR-25 increased the viability and proliferation of OMECs, and the content of triglycerides in OMECs. In addition, INSIG1 was found to be a target gene of miR-25 using a dual-luciferase reporter assay. Overexpression of INSIG1 decreased the viability, proliferation, and level of triglycerides of OMECs. In contrast, the inhibition of INSIG1 in expression had the opposite effect on activities and triglycerides of OMECs with overexpressed INSIG1. A rescue experiment revealed that circ_015343 alleviated the inhibitory effect of miR-25 on the mRNA and protein abundance of INSIG1. These results indicate that circ_015343 sponges miR-25 to inhibit the activities and content of triglycerides of OMECs by upregulating the expression of INSIG1 in OMECs. This study provided new insights for understanding the genetic molecular mechanism of lactation traits in sheep.

MECOM and the PRDM gene family in uterine endometrial cancer: bioinformatics and experimental insights into pathogenesis and therapeutic potentials

To elucidate the expression profiles, methylation states, and clinicopathological significance of the PRDM gene family, focusing on the MECOM gene's role in uterine endometrial cancer (UCEC) and its molecular interactions with the TGF-beta signaling pathway. Our methodology combined detailed bioinformatics analyses using UALCAN and GEPIA with in vitro assessments in HEC-1-A cells. Techniques included CRISPR-Cas9 for gene editing and various cellular assays (CCK-8, flow cytometry, Transwell) to evaluate the effects of MECOM on cell proliferation, migration, and apoptosis, alongside Western blot analysis for protein regulation in the TGF-beta pathway. MECOM was upregulated in UCEC tissues, influencing tumor cell behavior significantly. Knockout studies demonstrated reduced proliferation and migration and increased apoptosis, while overexpression showed reverse effects. Mechanistically, MECOM modulated critical proteins within the TGF-beta pathway, impacting cell cycle dynamics and apoptotic processes. The PRDM gene family, particularly MECOM, plays a crucial role in the pathogenesis and progression of UCEC, suggesting its utility as a target for novel therapeutic interventions. Our findings offer valuable insights for future research and potential clinical application in managing uterine endometrial cancer.

Deciphering the role of SAMHD1 in endometrial cancer progression

BACKGROUND

Endometrial cancer (EC) presents significant clinical challenges due to its heterogeneity and complex pathophysiology. SAMHD1, known for its role as a deoxynucleotide triphosphate triphosphohydrolase, has been implicated in the progression of various cancers, including EC. This study focuses on elucidating the role of SAMHD1 in EC through its impact on TRIM27-mediated PTEN ubiquitination.

RESULTS

Utilizing a combination of bioinformatics and cellular biology techniques, we investigated the interactions among SAMHD1, TRIM27, and PTEN. Our findings reveal that SAMHD1 modulates PTEN ubiquitination via TRIM27, impacting key pathways involved in EC pathogenesis. These interactions suggest a critical mechanism by which SAMHD1 could influence tumor behavior and progression in EC.

CONCLUSIONS

The results from this study underscore the potential of targeting the SAMHD1-TRIM27-PTEN axis as a therapeutic strategy in EC. By providing new insights into the molecular mechanisms underlying EC progression, our research supports the development of novel therapeutic approaches that could contribute to improve treatment strategies for patients with EC.

circRNAs in Endometrial Cancer-A Promising Biomarker: State of the Art

Endometrial cancer (EC) is one of the most common malignant tumors among women in the 21st century, whose mortality rate is increasing every year. Currently, the diagnosis of EC is possible only after a biopsy. However, it is necessary to find a new biomarker that will help in both the diagnosis and treatment of EC in a non-invasive way. Circular RNAs (circRNAs) are small, covalently closed spherical and stable long non-coding RNAs (lncRNAs) molecules, which are abundant in both body fluids and human tissues and are expressed in various ways. Considering the new molecular classification of EC, many studies have appeared, describing new insights into the functions and mechanisms of circRNAs in EC. In this review article, we focused on the problem of EC and the molecular aspects of its division, as well as the biogenesis, functions, and diagnostic and clinical significance of circRNAs in EC.

Clinicopathological role of Cyclin A2 in uterine corpus endometrial carcinoma: Integration of tissue microarrays and ScRNA-Seq

BACKGROUND

The comprehensive expression level and potential molecular role of Cyclin A2 (CCNA2) in uterine corpus endometrial carcinoma (UCEC) remains undiscovered.

METHODS

UCEC and normal endometrium tissues from in-house and public databases were collected for investigating protein and messenger RNA expression of CCNA2. The transcription factors of CCNA2 were identified by the Cistrome database. The prognostic significance of CCNA2 in UCEC was evaluated through univariate and multivariate Cox regression as well as Kaplan-Meier curve analysis. Single-cell RNA-sequencing (scRNA-seq) analysis was performed to explore cell types in UCEC, and the AUCell algorithm was used to investigate the activity of CCNA2 in different cell types.

RESULTS

A total of 32 in-house UCEC and 30 normal endometrial tissues as well as 720 UCEC and 165 control samples from public databases were eligible and collected. Integrated calculation showed that the CCNA2 expression was up-regulated in the UCEC tissues (SMD = 2.43, 95% confidence interval 2.23∼2.64). E2F1 and FOXM1 were identified as transcription factors due to the presence of binding peaks on transcription site of CCNA2. CCNA2 predicted worse prognosis in UCEC. However, CCNA2 was not an independent prognostic factor in UCEC. The scRNA-seq analysis disclosed five cell types: B cells, T cells, monocytes, natural killer cells, and epithelial cells in UCEC. The expression of CCNA2 was mainly located in B cells and T cells. Moreover, CCNA2 was active in T cells and B cells using the AUCell algorithm.

CONCLUSION

CCNA2 was up-regulated and mainly located in T cells and B cells in UCEC. Overexpression of CCNA2 predicted unfavorable prognosis of UCEC.

XRCC1 and hOGG1 polymorphisms and endometrial carcinoma: A meta-analysis

Endometrial carcinoma's (EC) etiology is complex and involves DNA repair gene polymorphisms like XRCC1-Arg399Gln and hOGG1-Ser326Cys, but their association with the disease is unclear. Following PRISMA, we conducted a systematic review and meta-analysis, collecting data from four databases. The studies needed to be population-based case-control studies examining the association between the named polymorphisms and EC. Quality was assessed with the Newcastle-Ottawa Scale. Pooled odds ratios (OR) and 95% confidence intervals (CI) were calculated, and subgroup analyses were conducted based on ethnicity. Seven studies were included. Both polymorphisms were found to significantly increase EC risk, particularly in Caucasians. XRCC1-Arg399Gln showed a dominant model OR of 1.14 (95% CI: 1.01-1.29) and a homozygous model OR of 1.59 (95% CI: 1.12-2.25). The heterozygote model OR for hOGG1-Ser326Cys was 1.29 (95% CI: 1.02-1.63), and the allele OR was 1.31 (95% CI: 1.07-1.60). XRCC1-Arg399Gln and hOGG1-Ser326Cys may increase EC risk, primarily in Caucasian women, emphasizing the role of DNA repair in disease susceptibility. More extensive studies are needed to validate these findings in diverse ethnicities and investigate other DNA repair gene polymorphisms.

Number of Positive Lymph Nodes and Survival in Endometrial Carcinoma: A Proposal for a Modified Staging

Purpose

To construct a new clinical staging system including the number of lymph node metastases to supplement the International Federation of Gynecology and Obstetrics (FIGO) staging for the prognosis of endometrial carcinoma patients.

Methods

This cohort study retrieved the data of 28,824 patients confirmed as endometrial carcinoma between 2010 and 2015 in the surveillance, epidemiology, and end results (SEER) database. COX risk proportional model was established to evaluate the association between FIGO staging with the all-cause mortality of endometrial carcinoma. The diagnostic value of FIGO staging and the new staging for the mortality of patients were evaluated by receiver operator characteristic curve (ROC). Hazard ratio (HR) and 95% confidence interval (CI) were effect size.

Results

The 5-year survival rate of all participants was 77.21%. The median follow-up time was 60.00 (60.00,60.00) months. Patients at FIGO staging IB (HR=1.75, 95% CI: 1.62-1.90), FIGO staging II (HR=2.22, 95% CI: 2.00-2.47), FIGO staging IIIA (HR=2.74, 95% CI: 2.43-3.09), FIGO staging IIIB (HR=4.07, 95% CI: 3.48-4.76), FIGO staging IIIC1 (HR=3.84, 95% CI: 3.52-4.20), FIGO staging IIIC2 (HR=4.52, 95% CI: 4.09-4.99), FIGO staging IVA (HR=5.56, 95% CI: 4.58-6.74), and FIGO staging IVB (HR=7.62, 95% CI: 6.94-8.36) were associated with increased risk of all-cause mortality of endometrial carcinoma patients. After adding positive lymph nodes as another covariate in Model 3, the effect on of FIGO staging survival was reduced when the FIGO staging was higher than stage III/IV. The C-index of the new staging 0.781 (95% CI: 0.774-0.787) was higher than FIGO staging 0.776 (95% CI: 0.770-0.783).

Conclusion

Our new staging using the number of positive lymph nodes supplement to the FIGO staging was superior than the FIGO staging for predicting the prognosis of endometrial cancer patients, which might help more accurately identify endometrial carcinoma patients who were at high risk of mortality and offer timely treatments in these patients.

Circular RNA hsa_circ_0005218 promotes the early recurrence of hepatocellular carcinoma by targeting the miR-31-5p/CDK1 pathway

Increasing evidence has manifested that circular RNAs (circRNAs) exhibited critical function in regulating various signaling pathways related to hepatocellular carcinoma (HCC) recurrence. However, the role and mechanism of the circRNAs in the HCC early recurrence remain elusive. In this study, high-throughput RNA-sequencing (RNA-seq) analysis was conducted to identify the expression profile of circRNAs in HCC tissues and circ_0005218 was identified as one circRNA that significantly up-regulated in early recurrent HCC tissues. And patients with high expression of circ_0005218 showed worsen overall survival (OS) and disease-free survival (DFS). Moreover, the promotion effects of circ_0005218 on HCC cells in term of proliferation, invasion and metastasis were confirmed both in vitro and vivo by gain- and loss-of function assays. In addition, dual-luciferase reporter assays showed that circ_0005218 could competitively bind to micro-RNA (miR)-31-5p. Furthermore, we showed that suppression of CDK1 by miR-31-5p could be partially rescued by up-regulating circ_0005218. Taken together, the present study indicates that circ_0005218 absorbed miR-31-5p as a sponge to weaken its suppression on CDK1 expression, and thus boost HCC cell invasion and migration, which would act as a potential biomarker to predict the HCC early recurrence and as a new therapeutic target for treatment of HCC.