Ovarian Cancer Genetics and Implications for Imaging and Therapy

Characterization of Primary Mucinous Ovarian Cancer by Diffusion-Weighted and Dynamic Contrast Enhancement MRI in Comparison with Serous Ovarian Cancer

(1) Background. The purpose of this study is to evaluate the diagnostic accuracy of a quantitative analysis of diffusion-weighted imaging (DWI) and dynamic contrast enhanced (DCE) MRI of mucinous ovarian cancer (MOC). It also aims to differentiate between low grade serous carcinoma (LGSC), high-grade serous carcinoma (HGSC) and MOC in primary tumors. (2) Materials and Methods. Sixty-six patients with histologically confirmed primary epithelial ovarian cancer (EOC) were included in the study. Patients were divided into three groups: MOC, LGSC and HGSC. In the preoperative DWI and DCE MRI, selected parameters were measured: apparent diffusion coefficients (ADC), time to peak (TTP), and perfusion maximum enhancement (Perf. Max. En.). ROI comprised a small circle placed in the solid part of the primary tumor. The Shapiro-Wilk test was used to test whether the variable had a normal distribution. The Kruskal-Wallis ANOVA test was used to determine the p-value needed to compare the median values of interval variables. (3) Results. The highest median ADC values were found in MOC, followed by LGSC, and the lowest in HGSC. All differences were statistically significant (p < 0.000001). This was also confirmed by the ROC curve analysis for MOC and HGSC, showing that ADC had excellent diagnostic accuracy in differentiating between MOC and HGSC (p < 0.001). In the type I EOCs, i.e., MOC and LGSC, ADC has less differential value (p = 0.032), and TTP can be considered the most valuable parameter for diagnostic accuracy (p < 0.001). (4) Conclusions. DWI and DCE appear to be very good diagnostic tools in differentiating between serous carcinomas (LGSC, HGSC) and MOC. Significant differences in median ADC values between MOC and LGSC compared with those between MOC and HGSC indicate the usefulness of DWI in differentiating between less and more aggressive types of EOC, not only among the most common serous carcinomas. ROC curve analysis showed that ADC had excellent diagnostic accuracy in differentiating between MOC and HGSC. In contrast, TTP showed the greatest value for differentiating between LGSC and MOC.

Detection of ESR1 Mutations in Primary Tumors and Plasma Cell-Free DNA in High-Grade Serous Ovarian Carcinoma Patients

Simple Summary

In the present study we evaluated the frequency and the clinical relevance of ESR1 mutations in high-grade serous ovarian cancer (HGSOC). Drop-off droplet digital PCR (ddPCR) was first used to screen for ESR1 mutations in primary tumors (formalin-fixed paraffin-embedded, FFPEs) from HGSOC patients and plasma cell-free DNA (cfDNA) samples from advanced and metastatic ovarian cancer patients. We further used the recently developed ESR1-NAPA assay to detect individual ESR1 mutations in drop-off ddPCR-positive samples. We report for the first time the presence of ESR1 mutations in 15% of FFPEs and in 13.8% of plasma cfDNA samples from advanced and metastatic ovarian cancer patients.

Abstract

ESR1 mutations have been recently associated with resistance to endocrine therapy in metastatic breast cancer and their detection has led to the development and current evaluation of novel, highly promising therapeutic strategies. In ovarian cancer there have been just a few reports on the presence of ESR1 mutations. The aim of our study was to evaluate the frequency and the clinical relevance of ESR1 mutations in high-grade serous ovarian cancer (HGSOC). Drop-off droplet digital PCR (ddPCR) was first used to screen for ESR1 mutations in 60 primary tumors (FFPEs) from HGSOC patients and in 80 plasma cell-free DNA (cfDNA) samples from advanced and metastatic ovarian cancer patients. We further used our recently developed ESR1-NAPA assay to identify individual ESR1 mutations in drop-off ddPCR-positive samples. We report for the first time the presence of ESR1 mutations in 15% of FFPEs and in 13.8% of plasma cfDNA samples from advanced and metastatic ovarian cancer patients. To define the clinical significance of this finding, our results should be further validated in a large and well-defined cohort of ovarian cancer patients.

The Value of Magnetic Resonance Diffusion-Weighted Imaging and Dynamic Contrast Enhancement in the Diagnosis and Prognosis of Treatment Response in Patients with Epithelial Serous Ovarian Cancer

Background. The aim of our study was to describe the selected parameters of diffusion-weighted imaging (DWI) and perfusion dynamic contrast enhancement (DCE) MRI in primary tumors in patients with serous epithelial ovarian cancer (EOC), as well as in disease course prognosis and treatment response, including bevacizumab maintenance therapy. Materials and Methods. In total, 55 patients with primary serous EOC were enrolled in the study. All patients underwent MR imaging using a 1.5 T clinical whole-body MR system in preoperative DWI and DCE MRI selected parameters: apparent diffusion coefficients (ADC), time to peek (TTP) and perfusion maximum enhancement (Perf. Max. En.) were measured. The data were compared with histopathological and immunochemistry results (with Ki67 and VEGF expression) and clinical outcomes. Results. Higher mean ADC values were found in low-grade EOC compared to high-grade EOC: 1151.27 vs. 894,918 (p < 0.0001). A negative correlation was found between ADC and Ki67 expression (p = 0.027), and between ADC and VEGF expression (p = 0.042). There was a negative correlation between TTP and PFS (p = 0.0019) and Perf. Max. En. and PSF (p = 0.003). In the Kaplan−Meier analysis (log rank), a longer PFS was found in patients with ADC values greater than the median; p = 0.046. The Kaplan−Meier analysis showed a longer PFS (p = 0.0126) in a group with TTP below the mean value for this parameter in patients who received maintenance treatment with bevacizumab. Conclusions. The described relationships between PFS and DCE and DWI allow us to hope to include these parameters in the group of EOC prognostic factors. This aspect seems to be of particular interest in the case of the association of PFS with DCE values in the group of patients treated with bevacizumab.

Circ_0078607 inhibits the progression of ovarian cancer via regulating the miR-32-5p/SIK1 network

Background

Circular RNA (circRNA) has been shown to be involved in the regulation of human disease progression, including ovarian cancer (OC). Circ_0078607 was found to participate in OC progression. But its function and mechanism in OC deserve further exploration.

Methods

The expression levels of circ_0078607, salt-inducible kinase 1 (SIK1) and microRNA (miR)-32-5p were examined by qRT-PCR. And the protein expression levels of SIK1, metastasis marker and apoptosis marker were determined using western blot analysis. EDU staining, colony formation assay, transwell assay and flow cytometry were used to detect the proliferation, migration, invasion and apoptosis of cells. Moreover, dual-luciferase reporter assay was employed to verify the interaction between miR-32-5p and circ_0078607 or SIK1. Xenograft models were constructed to perform in vivo experiments.

Results

Circ_0078607 and SIK1 were downregulated in OC tissues and cells. Overexpressed circ_0078607 and SIK1 could inhibit OC cell proliferation, migration, invasion, and promote apoptosis. MiR-32-5p could be sponged by circ_0078607, and its overexpression could reverse the suppressive effect of circ_0078607 on OC progression. Furthermore, SIK1 was a target of miR-32-5p, and circ_0078607 could regulate SIK1 by sponging miR-32-5p. The inhibitory effect of circ_0078607 on OC progression also could be reversed by SIK1 silencing. In vivo experiments showed that circ_0078607 reduced OC tumorigenesis by regulating the miR-32-5p/SIK1 axis.

Conclusion

Circ_0078607 could serve as a sponge of miR-32-5p to regulate SIK1 expression, thereby inhibiting OC progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13048-021-00931-9.

Circ_0078607 acts as a sponge of miR-32-5p.

MiR-32-5p targets SIK1.

Long noncoding RNA DARS-AS1 regulates TP53 ubiquitination and affects ovarian cancer progression by modulation miR-194-5p/RBX1 axis

BACKGROUND

Ovarian cancer is a malignant tumor with a poor prognosis, its underlying mechanism is still unclear.

OBJECTIVE

In this study, long noncoding RNA DARS-AS1 was studied to identify its function in the development of ovarian cancer.

METHODS

Perform functional experiments to detect the effects of DARS-AS1 on the proliferation, apoptosis, and migration of ovarian cancer cells A2780. The luciferase report, immunoprecipitation (IP) experiment, and ubiquitination level determination verify that RBX1 ubiquitination and mediate the degradation of tumor suppressor gene TP53.

RESULTS

Knockdown of DARS-AS1 can inhibit cell proliferation, migration, and apoptosis, and the application of miR-194-5p inhibitors can prevent this process. Luciferase and IP experiments showed that DARS-AS1 regulates the expression of RBX1 by binding to miR-194-5p, and RBX1 mediates its degradation through ubiquitination of TP53.

Current update on malignant epithelial ovarian tumors

Epithelial ovarian cancer (EOC) represents the most frequently occurring gynecological malignancy, accounting for more than 70% of ovarian cancer deaths. Preoperative imaging plays an important role in assessing the extent of disease and guides the next step in surgical decision-making and operative planning. In this article, we will review the multimodality imaging features of various subtypes of EOC. We will also discuss the role of imaging in the staging, management, and surveillance of EOC.

Comprehensive Analysis of Tumor Microenvironment Identified Prognostic Immune-Related Gene Signature in Ovarian Cancer

Background

Accumulating evidence demonstrated that tumor microenvironmental cells played important roles in predicting clinical outcomes and therapeutic efficacy. We aimed to develop a reliable immune-related gene signature for predicting the prognosis of ovarian cancer (OC).

Methods

Single sample gene-set enrichment analysis (ssGSEA) of immune gene-sets was used to quantify the relative abundance of immune cell infiltration and develop high- and low-abundance immune subtypes of 308 OC samples. The presence of infiltrating stromal/immune cells in OC tissues was calculated as an estimate score. We estimated the correlation coefficients among the immune subtype, clinicopathological feature, immune score, distribution of immune cells, and tumor mutation burden (TMB). The differentially expressed immune-related genes between high- and low-abundance immune subtypes were further used to construct a gene signature of a prognostic model in OC with lasso regression analysis.

Results

The ssGSEA analysis divided OC samples into high- and low-abundance immune subtypes based on the abundance of immune cell infiltration, which was significantly related to the estimate score and clinical characteristics. The distribution of immune cells was also significantly different between high- and low-abundance immune subtypes. The correlation analysis showed the close relationship between TMB and the estimate score. The differentially expressed immune-related genes between high- and low-abundance immune subtypes were enriched in multiple immune-related pathways. Some immune checkpoints (PDL1, PD1, and CTLA-4) were overexpressed in the high-abundance immune subtype. Furthermore, the five-immune-related-gene-signature prognostic model (CCL18, CXCL13, HLA-DOB, HLA-DPB2, and TNFRSF17)-based high-risk and low-risk groups were significantly related to OC overall survival.

Conclusion

Immune-related genes were the promising predictors of prognosis and survival, and the comprehensive landscape of tumor microenvironmental cells of OC has potential for therapeutic schedule monitoring.

METTL3-mediated maturation of miR-126-5p promotes ovarian cancer progression via PTEN-mediated PI3K/Akt/mTOR pathway

Methyltransferase-like 3 (METTL3) functions as an RNA methyltransferase that controls the modification of N(6)-methyladenosine (m6A) to influence the biosynthesis, decay, and translation of mRNAs. This study aims to investigate the regulation of METTL3-mediated promotion of microRNA-126-5p (miR-126-5p) in the progression of ovarian cancer and to identify the mechanisms in relation to phosphatase and tensin homolog (PTEN) and the PI3K/Akt/mTOR pathway. We found high expression of miR-126-5p in ovarian cancer samples compared to paired adjacent samples, and also in ovarian cancer cell lines. Gain-of-function experiments demonstrated that overexpression of miR-126-5p promoted ovarian cancer cell proliferation, migration, and invasion, and inhibited their apoptosis. Luciferase reporter assay identified that miR-126-5p could directly bind to PTEN. By targeting PTEN, miR-126-5p could activate the PI3K/Akt/mTOR pathway. Furthermore, the RNA methyltransferase METTL3 promoted the maturation of miR-126-5p via the m6A modification of pri-miR-126-5p. Finally, in vitro and in vivo experiments substantiated that silencing of METTL3 impeded the progression and tumorigenesis of ovarian cancer by impairing the miR-126-5p-targeted inhibition of PTEN and thus blocking the PI3K/Akt/mTOR pathway. Coherently, knockdown of METTL3 inhibited the effect of miR-126-5p to upregulate PTEN, and thus prevents PI3K/Akt/mTOR pathway activation, thereby suppressing the development of ovarian cancer. These findings highlight potential targets for the future ovarian cancer treatment as well as tumorigenic mechanisms mediated by m6A modification.

Cancer and SOX proteins: New insight into their role in ovarian cancer progression/inhibition

Transcription factors are potential targets in disease therapy, particularly in cancer. This is due to the fact that transcription factors regulate a variety of cellular events, and their modulation has opened a new window in cancer therapy. Sex-determining region Y (SRY)-related high-mobility group (HMG) box (SOX) proteins are potential transcription factors that are involved in developmental processes such as embryogenesis. It has been reported that abnormal expression of SOX proteins is associated with development of different cancers, particularly ovarian cancer (OC). In the present review, our aim is to provide a mechanistic review of involvement of SOX members in OC. SOX members may suppress and/or promote aggressiveness and proliferation of OC cells. Clinical studies have also confirmed the potential of transcription factors as diagnostic and prognostic factors in OC. Notably, studies have demonstrated the relationship between SOX members and other molecular pathways such as ST6Ga1-I, PI3K, ERK and so on, leading to more complexity. Furthermore, SOX members can be affected by upstream mediators such as microRNAs, long non-coding RNAs, and so on. It is worth mentioning that the expression of each member of SOX proteins is corelated with different stages of OC. Furthermore, their expression determines the response of OC cells to chemotherapy. These topics are discussed in this review to shed some light on role of SOX transcription factors in OC.

Does dual-energy CT differentiate benign and malignant ovarian tumours?

AIM

To assess the ability of dual-energy computed tomography (DECT) to distinguish benign from malignant ovarian tumours (OTs).

MATERIALS AND METHODS

Following approval of the institutional review board, the institutional database was mined for treatment-naive patients who underwent primary cytoreduction for OT. Thirty-seven patients were included and divided into those with benign OTs (n = 11) and malignant OTs (n = 26), including high-grade (n = 20) and low-grade (n = 6) malignant OTs. Advanced processing and region of interest delineation on the ovarian mass were performed using the preoperative staging DECT examination using the Advantage Workstation. The pixel-level data of the CT attenuation values at 50, 70, and 120 keV and the effective atomic number (Z_eff), water content (WC), and iodine content (IC) in the ovarian mass were recorded. The Wilcoxon rank-sum test was used to compare CT attenuation data at different voltages, Z_eff, and WC and IC levels between benign and malignant OTs and between high- and low-grade malignant OTs. Simple logistic regression was used to correlate the imaging characteristics with malignant status and grade.

RESULTS

Malignant OTs had significantly higher Z_eff and IC compared with benign OTs. The threshold values for the diagnosis of malignant OT were IC≥9.74 (100 μg/cm³) with 81% sensitivity and 73% specificity and Z_eff ≥8.16 with 85% sensitivity and 73% specificity. High-grade OTs had significantly higher WC compared with low-grade OTs, and a threshold of ≥1,013.92 mg/cm³ differentiated them with 80% sensitivity and 83% specificity.

CONCLUSION

DECT may be a tool to help distinguish malignant and benign OTs and predict tumour grade.