A survival analysis comparing women with ovarian low-grade serous carcinoma to those with high-grade histology

The impact of varying levels of residual disease following cytoreductive surgery on survival outcomes in patients with ovarian cancer: a meta-analysis

BACKGROUND

Residual disease following cytoreductive surgery in patients with ovarian cancer has been associated with poorer survival outcomes compared with no residual disease. We performed a meta-analysis to assess the impact of varying levels of residual disease status on survival outcomes in patients with ovarian cancer who have undergone primary cytoreductive surgery or interval cytoreductive surgery in the setting of new therapies for this disease.

METHODS

Medline, Embase, and Cochrane databases (January 2011 - July 2020) and grey literature, bibliographic and key conference proceedings, were searched for eligible studies. Fixed and random-effects meta-analyses compared progression and survival by residual disease level across studies. Heterogeneity between comparisons was explored via type of surgery, disease stage, and type of adjuvant chemotherapy.

RESULTS

Of 2832 database and 16 supplementary search articles screened, 50 studies were selected; most were observational studies. The meta-analysis showed that median progression-free survival and overall survival decreased progressively with increasing residual disease (residual disease categories of 0 cm, > 0-1 cm and > 1 cm). Compared with no residual disease, hazard ratios (HR) for disease progression increased with increasing residual disease category (1.75 [95% confidence interval: 1.42, 2.16] for residual disease > 0-1 cm and 2.14 [1.34, 3.39] for residual disease > 1 cm), and also for reduced survival (HR versus no residual disease, 1.75 [ 1.62, 1.90] for residual disease > 0-1 cm and 2.32 [1.97, 2.72] for residual disease > 1 cm). All comparisons were significant (p < 0.05). Subgroup analyses showed an association between residual disease and disease progression/reduced survival irrespective of type of surgery, disease stage, or type of adjuvant chemotherapy.

CONCLUSIONS

This meta-analysis provided an update on the impact of residual disease following primary or interval cytoreductive surgery, and demonstrated that residual disease was still highly predictive of progression-free survival and overall survival in adults with ovarian cancer despite changes in ovarian cancer therapy over the last decade. Higher numerical categories of residual disease were associated with reduced survival than lower categories.

The pivotal role of long non-coding RNAs as potential biomarkers and modulators of chemoresistance in ovarian cancer (OC)

Ovarian cancer (OC) is a fatal gynecological disease that is often diagnosed at later stages due to its asymptomatic nature and the absence of efficient early-stage biomarkers. Previous studies have identified genes with abnormal expression in OC that couldn't be explained by methylation or mutation, indicating alternative mechanisms of gene regulation. Recent advances in human transcriptome studies have led to research on non-coding RNAs (ncRNAs) as regulators of cancer gene expression. Long non-coding RNAs (lncRNAs), a class of ncRNAs with a length greater than 200 nucleotides, have been identified as crucial regulators of physiological processes and human diseases, including cancer. Dysregulated lncRNA expression has also been found to play a crucial role in ovarian carcinogenesis, indicating their potential as novel and non-invasive biomarkers for improving OC management. However, despite the discovery of several thousand lncRNAs, only one has been approved for clinical use as a biomarker in cancer, highlighting the importance of further research in this field. In addition to their potential as biomarkers, lncRNAs have been implicated in modulating chemoresistance, a major problem in OC. Several studies have identified altered lncRNA expression upon drug treatment, further emphasizing their potential to modulate chemoresistance. In this review, we highlight the characteristics of lncRNAs, their function, and their potential to serve as tumor markers in OC. We also discuss a few databases providing detailed information on lncRNAs in various cancer types. Despite the promising potential of lncRNAs, further research is necessary to fully understand their role in cancer and develop effective strategies to combat this devastating disease.

Correlation between progression-free survival and overall survival in patients with ovarian cancer after cytoreductive surgery: a systematic literature review

OBJECTIVES

This analysis aimed to better define the relationship between progression-free survival and overall survival in adult patients with ovarian cancer (including fallopian tube or primary peritoneal cancer) following primary cytoreductive surgery or interval cytoreductive surgery.

METHODS

A systematic literature review was carried out across the Medline, Embase, and Cochrane Central databases on 7 July 2020 (date limits 1 January 2011 to 7 July 2020) to identify studies with the following eligibility criteria: clinical trials/observational studies including >200 patients with ovarian cancer aged ≥18 years, evaluating overall survival/progression-free survival following cytoreductive surgery by residual disease status in the United States, Europe, Japan, or China. Weighted linear regression models were used to assess any correlation between median progression-free survival and overall survival, and between logHR for progression-free survival and logHR for overall survival. Risk of bias was assessed for all included studies.

RESULTS

Of the 50 studies reported, 43 were observational studies (41 retrospective and two prospective cohort studies), and seven were reporting for randomized clinical trials-of which four were retrospective data analyses. For analyses of the relationship between overall survival and progression-free survival, 21 studies were eligible. The weighted linear regression model showed a strong positive association between the two survival endpoints. Goodness-of-fit analysis measured the adjusted R2 as 0.84 (p<0.001); a positive association was also observed between logHRs for overall survival and progression-free survival in the included studies.

CONCLUSIONS

Median progression-free survival was predictive of median overall survival. This correlation between progression-free survival and overall survival after primary treatment for ovarian cancer highlights the validity of progression-free survival as a primary endpoint. Observational studies contributed most data, with limited information on disease stage and histology.

Rare Epithelial Ovarian Cancers: Low Grade Serous and Mucinous Carcinomas

The ovarian epithelial cancer histotypes can be divided into common and rare types. Common types include high-grade serous ovarian carcinomas and the endometriosis-associated cancers, endometrioid and clear-cell carcinomas. The less common histotypes are mucinous and low-grade serous, each comprising less than 10% of all epithelial carcinomas. Although histologically and epidemiologically distinct from each other, these histotypes share some genetic and natural history features that distinguish them from the more common types. In this review, we will consider the similarities and differences of these rare histological types, and the clinical challenges they pose.

Cytoreductive Surgery With or Without HIPEC in the Management of Peritoneal Dissemination from Rare Histological Subtypes of Ovarian Cancer - a Retrospective Study by INDEPSO

The aim of this study was to evaluate the potential role of optimal cytoreductive surgery with or without HIPEC in the management of peritoneal dissemination from rare histological subtypes of ovarian cancer and to report the prognostic factors affecting survival. In this retrospective multicentric study, all patients with diagnosis of locally advanced ca ovary with histology other than high-grade serous carcinoma and those having undergone cytoreductive surgery (CRS) with or without hyperthermic intraperitoneal chemotherapy for the same were included. Factors affecting survival were evaluated in addition to studying the clinicopathological features. In the period from January 2013 to December 2021, 101 consecutive patients of ovarian cancer with rare histology underwent cytoreductive surgery with or without HIPEC. The median OS was not reached (NR), and the median PFS was 60 months. On evaluation of factors affecting overall survival (OS) and progression-free survival (PFS), PCI > 15 was associated with not only a decreased PFS (p = 0.019) but also a decreased OS (P = 0.019) on univariate and multivariate analysis. With respect to histology, the best OS and PFS were seen with granulosa cell tumor, mucinous tumors for which median OS and median PFS were NR respectively. Cytoreductive surgery can be performed with an acceptable morbidity in patients with peritoneal dissemination from ovarian tumors of rare histology. The role of HIPEC and impact of other prognostic factors on the treatment and survival outcome need further evaluation in larger series of patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13193-022-01640-5.

Exosomes as crucial emerging tools for intercellular communication with therapeutic potential in ovarian cancer

More than two-thirds of epithelial ovarian cancer (EOC) patients are diagnosed at advanced stages due to the lack of sensitive biomarkers. Currently, exosomes are intensively investigated as non-invasive cancer diagnostic markers. Exosomes are nanovesicles released in the extracellular milieu with the potential to modulate recipient cells' behavior. EOC cells release many altered exosomal cargoes that exhibit clinical relevance to tumor progression. Exosomes represent powerful therapeutic tools (drug carriers or vaccines), posing a promising option in clinical practice for curing EOC in the near future. In this review, we highlight the importance of exosomes in cell–cell communication, epithelial–mesenchymal transition (EMT), and their potential to serve as diagnostic and prognostic factors, particularly in EOC.

Evaluation of the prognostic value of lymphadenectomy for low-grade serous ovarian cancer: A case-control multicenter retrospective study

BACKGROUND

The prognostic value of lymphadenectomy in low-grade serous ovarian cancer (LGSOC) remains uncertain.

MATERIALS AND METHODS

A retrospective analysis of 155 patients with LGSOC who underwent surgery over a ten-year period (2011-2020) was performed. The propensity score matching (PSM) algorithm was performed between the lymphadenectomy and no lymphadenectomy groups, and Kaplan-Meier analyses were conducted to evaluate clinical prognosis. Finally, univariate and multivariate Cox proportional hazards regression analyses were performed to analyze high-risk factors associated with clinical prognosis.

RESULTS

In the pre-PSM cohort, 110 (71.0%) patients underwent lymphadenectomy. Of these, 54 (34.8%) experienced recurrence, and 27 (17.4%) died. There were statistical differences in disease-free survival (DFS) (P = 0.018) and overall survival (OS) (P = 0.016) in the post-PSM cohort. In the subgroup analysis, there were no statistically significant differences in DFS (P = 0.449) or OS (P = 0.167) in the FIGO I/II cohort. However, in the FIGO III/IV cohort, DFS (P = 0.011) and OS (P = 0.046) were statistically different between the two groups. Age > 50 years, FIGO stage III/IV, and suboptimal cytoreductive surgery were risk factors associated with prognosis. In the lymphadenectomy group, the histological status of pelvic lymph nodes had no significant effect on DFS (P = 0.205) or OS (P = 0.114).

CONCLUSION

Lymphadenectomy was associated with DFS and OS, particularly in patients with advanced LGSOC patients. Age > 50 years, advanced FIGO stage III/IV, and suboptimal cytoreductive surgery were high-risk factors associated with clinical prognosis in patients with LGSOC.

Development of Low-Grade Serous Ovarian Carcinoma from Benign Ovarian Serous Cystadenoma Cells

Simple Summary

Low-grade serous ovarian carcinoma (LGSOC) is thought to progress from benign cystadenoma in a stepwise fashion via serous borderline tumors (SBTs). This hypothesis is based on pathological and molecular evidence obtained following the genetic analysis of clinical samples from LGSOCs, SBTs, and cystadenomas. However, there have been no reports on the occurrence of LGSOCs following the introduction of oncogenes into benign serous cystadenoma cells. This study successfully developed an in vitro carcinogenic model of LGSOCs by introducing oncogenic KRAS and PIK3CA gene mutations in immortalized HOVs-cyst-1 cells from serous cystadenomas. The established mouse xenograft tumors resulting from the inoculation of HOVs-cyst-1 cells with KRAS and PIK3CA mutations exhibited the micropapillary invasive pattern of LGSOCs with low nuclear atypia without alveoli.

Abstract

Despite the knowledge about numerous genetic mutations essential for the progression of low-grade serous ovarian carcinoma (LGSOC), the specific combination of mutations required remains unclear. Here, we aimed to recognize the oncogenic mutations responsible for the stepwise development of LGSOC using immortalized HOVs-cyst-1 cells, developed from ovarian serous cystadenoma cells, and immortalized via cyclin D1, CDK4^R24C, and hTERT gene transfection. Furthermore, oncogenic mutations, KRAS and PIK3CA, were individually and simultaneously introduced in immortalized HOV-cyst-1 cells. Cell functions were subsequently analyzed via in vitro assays. KRAS or PIK3CA double mutant HOV-cyst-1 cells exhibited higher cell proliferation and migration capacity than the wild-type cells, or those with either a KRAS or a PIK3CA mutation, indicating that these mutations play a causative role in LGSOC tumorigenesis. Moreover, KRAS and PIK3CA double mutants gained tumorigenic potential in nude mice, whereas the cells with a single mutant exhibited no signs of tumorigenicity. Furthermore, the transformation of HOV-cyst-1 cells with KRAS and PIK3CA mutants resulted in the development of tumors that were grossly and histologically similar to human LGSOCs. These findings suggest that simultaneous activation of the KRAS/ERK and PIK3CA/AKT signaling pathways is essential for LGSOC development.

Clinical factors associated with prognosis in low-grade serous ovarian carcinoma: experiences at two large academic institutions in Korea and Taiwan

Low-grade ovarian serous carcinoma (LGSOC) has clinical features different from high-grade serous ovarian carcinoma (HGSOC) accounting for the majority of epithelial ovarian cancer. Because of its rarity, previous studies have only focused on the high-grade disease without considering the differences between the two subtypes. This study aimed to evaluate the effect of the clinical prognostic factors known for HGSOC on survival in patients with LGSOC. Based on the Federation of Gynecology and Obstetrics (FIGO) stage, progression-free survival (PFS) was markedly decreased in advanced disease compared with early disease. For stage I, patients with stage IC had poorer survival than those with stage IA and IB regardless of the number of cycles of adjuvant chemotherapy. For advanced disease, no gross residual disease after primary cytoreductive surgery was significantly associated with longer PFS when compared with gross residual disease. In multivariate analysis for PFS and overall survival (OS), age, preoperative CA-125, time interval from surgery to chemotherapy, and the number of cycles of adjuvant chemotherapy were not associated with prognosis. Complete cytoreduction was the only independent prognostic factor for PFS (HR 2.45, p = 0.045). Our study revealed that the known prognostic factors in HGSOC did not show any effect on the survival in LGSOC except for FIGO stage and complete cytoreduction.

Genomic analysis of low-grade serous ovarian carcinoma to identify key drivers and therapeutic vulnerabilities

Low-grade serous ovarian carcinoma (LGSOC) is associated with a poor response to existing chemotherapy, highlighting the need to perform comprehensive genomic analysis and identify new therapeutic vulnerabilities. The data presented here represent the largest genetic study of LGSOCs to date (n = 71), analysing 127 candidate genes derived from whole exome sequencing cohorts to generate mutation and copy-number variation data. Additionally, immunohistochemistry was performed on our LGSOC cohort assessing oestrogen receptor, progesterone receptor, TP53, and CDKN2A status. Targeted sequencing identified 47% of cases with mutations in key RAS/RAF pathway genes (KRAS, BRAF, and NRAS), as well as mutations in putative novel driver genes including USP9X (27%), MACF1 (11%), ARID1A (9%), NF2 (4%), DOT1L (6%), and ASH1L (4%). Immunohistochemistry evaluation revealed frequent oestrogen/progesterone receptor positivity (85%), along with CDKN2A protein loss (10%) and CDKN2A protein overexpression (6%), which were linked to shorter disease outcomes. Indeed, 90% of LGSOC samples harboured at least one potentially actionable alteration, which in 19/71 (27%) cases were predictive of clinical benefit from a standard treatment, either in another cancer's indication or in LGSOC specifically. In addition, we validated ubiquitin-specific protease 9X (USP9X), which is a chromosome X-linked substrate-specific deubiquitinase and tumour suppressor, as a relevant therapeutic target for LGSOC. Our comprehensive genomic study highlighted that there is an addiction to a limited number of unique 'driver' aberrations that could be translated into improved therapeutic paths. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Bioinformatics analysis of gene expression profile of serous ovarian carcinomas to screen key genes and pathways

Background

Serous ovarian carcinomas (SCA) are the most common and most aggressive ovarian carcinoma subtype which etiology remains unclear. To investigate the prospective role of mRNAs in the tumorigenesis and progression of SCA, the aberrantly expressed mRNAs were calculated based on the NCBI-GEO RNA-seq data.

Results

Of 21,755 genes with 89 SCA and SBOT cases from 3 independent laboratories, 59 mRNAs were identified as differentially expressed genes (DEGs) (|log₂Fold Change| > 1.585, also |FoldChange| > 3 and adjusted P < 0.05) by DESeq R. There were 26 up-regulated DEGs and 33 down-regulated DEGs screened. The hierarchical clustering analysis, functional analysis and pathway enrichment analysis were performed on all DEGs and found that Polo-like kinase (PLK) signaling events are important. PPI network constructed with different filtration conditions screened out 4 common hub genes (KIF11, CDC20, PBK and TOP2A). Mutual exclusivity or co-occurrence analysis of 4 hub genes identified a tendency towards co-occurrence between KIF11 and CDC20 or TOP2A in SCA (p < 0.05). To analyze further the potential role of KIF11 in SCA, the co-expression profiles of KIF11 in SCA were identified and we found that CDC20 co-expressed with KIF11 also is DEG that we screened out before. To verify our previous results in this paper, we assessed the expression levels of 4 hub DEGs (all up-regulated) and 4 down-regulated DEGs in Oncomine database. And the results were consistent with previous conclusions obtained from GEO series. The survival curves showed that KIF11, CDC20 and TOP2A expression are significantly related to prognosis of SCA patients.

Conclusions

From all the above results, we speculate that KIF11, CDC20 and TOP2A played an important role in SCA.

Does lymph node ratio have any prognostic significance in maximally cytoreduced node-positive low-grade serous ovarian carcinoma?

PURPOSE

To determine the prognostic impact of the lymph node ratio (LNR) in node-positive low-grade serous ovarian cancer (LGSOC).

METHODS

We retrospectively reviewed women with LGSOC who had undergone maximal cytoreduction followed by standard chemotherapy in 11 centers from Turkey during a study period of 20 years. Sixty two women with node-positive LGSOC were identified. LNR was defined as the number of metastatic lymph nodes (LNs) divided by the number of total LNs removed. We grouped patients pursuant to the LNR as LNR ≤ 0.09 and LNR > 0.09. The prognostic value of LNR was investigated by employing the univariate log-rank test and multivariate Cox-regression model.

RESULTS

With a median follow-up of 45 months, the 5-year progression-free survival (PFS) rates were 61.7% for women with LNR ≤ 0.09 and 32.0% for those with LNR > 0.09 (p = 0.046) whereas, the 5-year overall survival (OS) rates were 72.8% for LNR ≤ 0.09 and 54.7% for LNR > 0.09 (p = 0.043). On multivariate analyses, lymphovascular space invasion (LVSI) (Hazard Ratio [HR] 4.18, 95% confidence interval [CI] 1.88-9.27; p < 0.001), omental involvement (HR 3.48, 95% CI 1.36-8.84; p = 0.009) and LNR > 0.09 (HR 3.51, 95% CI 1.54-8.03; p = 0.003) were adverse prognostic factors for PFS. Additionally, LVSI (HR 6.56, 95% CI 2.33-18.41; p < 0.001), omental involvement (HR 6.34, 95% CI 1.86-21.57; p = 0.003) and LNR > 0.09 (HR 7.20, 95% CI 2.33-22.26; p = 0.001) were independent prognostic factors for decreased OS.

CONCLUSION

LNR > 0.09 seems to be an independent prognosticator for decreased survival outcomes in LGSOC patients who received maximal cytoreduction followed by standard adjuvant chemotherapy.

Correlation of differential ascites volume with primary cytoreductive surgery outcome, lymph node involvement, and disease recurrence in advanced ovarian cancer

OBJECTIVE

High-grade serous ovarian cancer accounts for a disproportionate number of deaths from gynecologic malignancies. It typically presents at an advanced stage and with a high volume of ascites a common presenting feature. The aims of this study is to evaluate the association between ascites volume at the time of primary surgery for advanced stage ovarian cancer with surgical outcomes and patterns of recurrence.

METHODS

A retrospective review of stage III/IV high-grade serous ovarian cancer patients who underwent primary surgery at two centers between March 2003 to June 2016. Patients were categorized as low-volume ascites (≤ 200 mL) vs high-volume (≥ 1 L). Patients with an unknown volume of ascites or neoadjuvant chemotherapy were excluded. Patients' characteristics were compared for the two groups. Probability of recurrence over time and the HR from a proportional hazards model for sub-distribution were calculated.

RESULTS

A total of 210 patients were included, 90 (42.9%) patients in the low-volume and 120 (57.1%) patients in the high-volume group. Patients in the low-volume group were older with a median age of 60.2 years vs 56.8 years in the high-volume group and had lower serum CA-125 levels (mean 223 vs 971.5 U/mL). The low-volume group had better surgical outcome with suboptimal debulking (> 1 cm residual disease) in only 17.8 % vs 39.2 % in the high-volume group and had longer median time to recurrence (2.8 years in low-volume vs 1.6 years high-volume group). At the time of recurrence, the low-volume group had a less disseminated pattern of recurrence, lower rates of ascites (20 % in the low-volume group vs 37.2 % in the high-volume group), and a trend toward lower serum CA125 levels (mean 352.8 vs 596.9 U/mL).

CONCLUSIONS

Advanced stage serous ovarian cancer patients who present with low-volume ascites have lower serum CA125 levels, more optimal cytoreduction rates, and longer disease-free interval. The low-volume group had less ascites, less disseminated disease, and a trend toward lower serum CA125 levels at the time of recurrence.

Measurement of Tumor Antioxidant Capacity and Prediction of Chemotherapy Resistance in Preclinical Models of Ovarian Cancer by Positron Emission Tomography

PURPOSE

Drug resistance is a major obstacle for the effective treatment of patients with high-grade serous ovarian cancer (HGSOC). Currently, there is no satisfactory way to identify patients with HGSOC that are refractive to the standard of care. Here, we propose the system xc - radiotracer (4S)-4-(3-[18F]fluoropropyl)-l-glutamate ([18F]FSPG) as a non-invasive method to measure upregulated antioxidant pathways present in drug-resistant HGSOC.

EXPERIMENTAL DESIGN

Using matched chemotherapy sensitive and resistant ovarian cancer cell lines, we assessed their antioxidant capacity and its relation to [18F]FSPG uptake, both in cells and in animal models of human ovarian cancer. We identified the mechanisms driving differential [18F]FSPG cell accumulation and evaluated [18F]FSPG tumor uptake as predictive marker of treatment response in drug-resistant tumors.

RESULTS

High intracellular glutathione (GSH) and low reactive oxygen species corresponded to decreased [18F]FSPG cell accumulation in drug-resistant versus drug-sensitive cells. Decreased [18F]FSPG uptake in drug-resistant cells was a consequence of changes in intracellular cystine, a key precursor in GSH biosynthesis. In vivo, [18F]FSPG uptake was decreased nearly 80% in chemotherapy-resistant A2780 tumors compared with parental drug-sensitive tumors, with nonresponding tumors displaying high levels of oxidized-to-reduced GSH. Treatment of drug-resistant A2780 tumors with doxorubicin resulted in no detectable change in tumor volume, GSH, or [18F]FSPG uptake.

CONCLUSIONS

This study demonstrates the ability of [18F]FSPG to detect upregulated antioxidant pathways present in drug-resistant cancer. [18F]FSPG may therefore enable the identification of patients with HGSOC that are refractory to standard of care, allowing the transferal of drug-resistant patients to alternative therapies, thereby improving outcomes in this disease.

Maximal cytoreduction is related to improved disease-free survival in low-grade ovarian serous carcinoma

Objective:

To evaluate the factors predicting oncologic outcomes in low-grade ovarian serous carcinoma (LGOSC).

Methods:

Seventy patients with LGOSC were included in the study. According to the residual disease present at the end of the initial cytoreductive surgery (CRS), surgical outcomes are defined as follows: maximal CRS for absence of macroscopic residual tumors, optimal CRS for macroscopic residual tumors with diameters ranging from 0.1 to ⩽1 cm diameter, and suboptimal CRS for macroscopic residual tumors measuring >1 cm in diameter.

Results:

Five-year disease-free survival (DFS) and cancer-specific survival (CSS) were 61% and 83%, respectively. Surgical outcomes were suboptimal in 3 (4.3%) patients, optimal in 8 (11.4%) patients, and maximal in 59 (84.3%) patients. Stage and surgical outcomes were related to DFS ( p < 0.05). Compared with maximal CRS, the presence of residual tumors (suboptimal and optimal debulking) was related to threefold increased risk of disease failure (recurrence or progression) (hazard ratio [95% confidence interval] 3.00 [1.27–7.09]; P=0.012). CSS was associated with disease stage alone ( P=0.03). Advanced stage was related with lower DFS and CSS.

Conclusions:

Maximal CRS facilitates an improvement in DFS. Achieving no residual disease after the completion of surgery should be a cornerstone of LGOSC management.

Multifunctional APJ Pathway Promotes Ovarian Cancer Progression and Metastasis

High mortality rates in ovarian cancer are due to late-stage diagnosis when extensive metastases are present, coupled with the eventual development of resistance to standard chemotherapy. There is, thus, an urgent need to identify targetable pathways to curtail this deadly disease. In this study, we show that the apelin receptor, APJ, is a viable target that promotes tumor progression of high-grade serous ovarian cancer (HGSOC). APJ is specifically overexpressed in tumor tissue, and is elevated in metastatic tissues compared with primary tumors. Importantly, increased APJ expression significantly correlates with decreased median overall survival (OS) by 14.7 months in patients with HGSOC. Using various ovarian cancer model systems, we demonstrate that APJ expression in cancer cells is both necessary and sufficient to increase prometastatic phenotypes in vitro, including proliferation, cell adhesion to various molecules of the extracellular matrix (ECM), anoikis resistance, migration, and invasion; and these phenotypes are efficiently inhibited by the APJ inhibitor, ML221. Overexpression of APJ also increases metastasis of ovarian cancer cells in vivo. Mechanistically, the prometastatic STAT3 pathway is activated downstream of APJ, and in addition to the ERK and AKT pathways, contributes to its aggressive phenotypes. Our findings suggest that the APJ pathway is a novel and viable target, with potential to curb ovarian cancer progression and metastasis. IMPLICATIONS: The APJ pathway is a viable target in HGSOC.

Epigenetics in ovarian cancer

Ovarian cancer is a disease with a poor prognosis and little progress has been made to improve treatment. It is now recognized that there are several histotypes of ovarian cancer, each with distinct epidemiologic and genomic characteristics. Cancer therapy is moving beyond classical chemotherapy to include epigenetic approaches. Epigenetics is the dynamic regulation of gene expression by DNA methylation and histone post translational modification in response to environmental cues. Improvement in technology to study DNA methylation has enabled a more agnostic approach and, with larger samples sets, has begun to unravel how epigenetics contributes to the etiology, response to chemotherapy and prognosis in of ovarian cancer. Investigations into histone modifications in ovarian cancer are more nascent. Much more is needed to be done to fully realize the potential that epigenetics holds for ovarian cancer clinical care.

The Interplay Between Epithelial-Mesenchymal Transition (EMT) and the Thyroid Hormones-αvβ3 Axis in Ovarian Cancer

Ovarian cancer is a highly metastatic disease. The metastatic potential is enhanced by epithelial to mesenchymal transition (EMT) in which αvβ3 integrin plays a role. Thyroid hormones (L-thyroxine, T4, and 3,5,3'-triiodo-L-thyronine, T3) bind this integrin, and we hypothesized that the thyroid hormone-αvβ3 axis may be involved in EMT activity in ovarian cancer. The transcription (mRNA), protein abundance (westerns), and protein localization (fluorescence microscopy) of several EMT markers were studied in ovarian cancer cells (OVCAR-3, A2780, and SKOV-3) treated with 1 nM T3 or 100 nM T4 for 1-24 h. The protein levels of β-catenin, and its downstream targets, zeb-1, slug, and vimentin, were significantly induced by both hormones, while the effect on transcription was limited. The pre-incubation of the cells overnight with two integrin inhibitors, RGD (0.1-10 μM) or αvβ3 blocking antibody (1-100 ng/mL), prevented the induction of β-catenin by T3 and zeb-1 by T4, indicating direct integrin involvement. The transcription of the mesenchymal markers, β-catenin, zeb-1, slug/snail, vimentin, and n-cadherin was hardly affected by T3 and T4, while that of the epithelial markers, e-cadherin and zo-1, was inhibited. Our results suggest a novel role for the thyroid hormone-αvβ3 axis in EMT, with possible implications for ovarian cancer metastasis.

Epithelial-to-Mesenchymal Transition in the Female Reproductive Tract: From Normal Functioning to Disease Pathology

Epithelial-to-mesenchymal transition (EMT) is a physiological process that is vital throughout the human lifespan. In addition to contributing to the development of various tissues within the growing embryo, EMT is also responsible for wound healing and tissue regeneration later in adulthood. In this review, we highlight the importance of EMT in the development and normal functioning of the female reproductive organs (the ovaries and the uterus) and describe how dysregulation of EMT can lead to pathological conditions, such as endometriosis, adenomyosis, and carcinogenesis. We also summarize the current literature relating to EMT in the context of ovarian and endometrial carcinomas, with a particular focus on how molecular mechanisms and the tumor microenvironment can govern cancer cell plasticity, therapy resistance, and metastasis.

Differences in MEK inhibitor efficacy in molecularly characterized low-grade serous ovarian cancer cell lines

Advanced or recurrent low-grade serous ovarian cancers (LGSC) are resistant to conventional systemic treatments. LGSC carry mutations in RAS or RAF, leading to several clinical trials evaluating MEK inhibitors (MEKi). As LGSC cell lines and xenografts have been difficult to establish, little is known about the efficacy and on-target activity of MEKi treatment in this disease. We compared four different MEKi (trametinib, selumetinib, binimetinib and refametinib) in novel LGSC patient-derived cell lines. Molecular characterization of these cells included copy-number variation and hotspot mutational analysis. Proliferation, apoptosis and cell viability assays were used to study drug efficacy. MEKi on-target efficacy was measured using western blotting and isoelectric point focusing for ERK1/2 phosphorylation. Ten LGSC cell lines were derived from 7 patients with advanced/recurrent disease. Copy number variation showed significant heterogeneity among cell lines, however all samples showed deletions in chromosome 9p21.3, and frequent copy number gains in chromosomes 12 and 20. Mutations in KRAS/NRAS were identified in 4 patients (57%) and RAS mutation status was not associated with higher baseline levels of ERK phosphorylation. Different degrees of MEKi sensitivity were observed in the LGSC cell lines. Two cell lines, both with KRAS mutations, were highly sensitive to MEKi. Drug anti-proliferative efficacy correlated with the degree of inhibition of ERK phosphorylation, with trametinib being the most potent agent. Differences in MEKi efficacy were observed in LGSC cell lines. Trametinib showed the greatest anti-proliferative effects. This study serves as a basis for much needed future research on MEKi drug efficacy in LGSC.

Low-grade serous ovarian cancer: A review

Epithelial ovarian cancers can be divided into the more common, aggressive type II cancers and the less common, slow-growing type I cancers. Under this model, serous ovarian carcinomas can be subdivided into high-grade (type II) and low-grade (type I) tumours. The two-tier system for grading serous ovarian carcinomas is superior to more detailed grading systems in terms of predicting survival. Low-grade serous carcinomas typically present in young women and have a relatively good prognosis, despite being resistant to chemotherapy. Low-grade serous cancers have a high prevalence of KRAS and BRAF mutations, but a low prevalence of TP53 mutations (which are characteristic of high-grade serous cancers). Among women with low-grade serous ovarian cancer, the presence of a KRAS/BRAF mutation is a favorable prognostic factor. Studies of the mitogen-activated protein kinase (MAPK) inhibitor in low-grade serous ovarian cancer suggest that identifying MAPK mutations might eventually be useful in guiding treatment.

Low-grade epithelial ovarian cancer: a number of distinct clinical entities?

PURPOSE OF REVIEW

The purpose of this study is to summarize the contemporary understanding of low-grade epithelial ovarian cancers.

RECENT FINDINGS

Low-grade serous ovarian cancer is biologically distinct from high-grade serous ovarian cancer. It is associated with a high incidence of K-RAS and B-RAF mutations. Although described as indolent due to median progression-free and overall survivals of 20 and 99 months, respectively, with a median age of diagnosis of 43 years, it accounts for a significant number of patient-years lost. Retrospective studies suggest response rates of 5% for chemotherapy and 9% for antioestrogen therapy. A prospective study of the mitogen-activated protein kinase kinase inhibitor selumetinib (response rate 15%) and retrospective bevacizumab studies suggest that these may be more effective approaches.Limited retrospective clinical data and even more sparse molecular data suggest that similar distinctions may exist between low-grade endometrioid and mucinous ovarian cancers and their respective high-grade counterparts, but more research is required in order to clarify the biological differences and the implications that these have for management.

SUMMARY

The results of phase III mitogen-activated protein kinase kinase inhibitor studies in low-grade serous ovarian cancer and further clinical and biological assessment of low-grade endometrioid and mucinous ovarian cancers are urgently required.

MAP3K8/TPL-2/COT is a potential predictive marker for MEK inhibitor treatment in high-grade serous ovarian carcinomas

Ovarian cancer is a silent disease with a poor prognosis that urgently requires new therapeutic strategies. In low-grade ovarian tumours, mutations in the MAP3K BRAF gene constitutively activate the downstream kinase MEK. Here we demonstrate that an additional MAP3K, MAP3K8 (TPL-2/COT), accumulates in high-grade serous ovarian carcinomas (HGSCs) and is a potential prognostic marker for these tumours. By combining analyses on HGSC patient cohorts, ovarian cancer cells and patient-derived xenografts, we demonstrate that MAP3K8 controls cancer cell proliferation and migration by regulating key players in G1/S transition and adhesion dynamics. In addition, we show that the MEK pathway is the main pathway involved in mediating MAP3K8 function, and that MAP3K8 exhibits a reliable predictive value for the effectiveness of MEK inhibitor treatment. Our data highlight key roles for MAP3K8 in HGSC and indicate that MEK inhibitors could be a useful treatment strategy, in combination with conventional chemotherapy, for this disease.

Akt2/ZEB2 may be a biomarker for exfoliant cells in ascitic fluid in advanced grades of serous ovarian carcinoma

Ovarian cancers present a mild clinical course when diagnosed early but an aggressive pathway when diagnosed in the peri- and postmenopausal periods. However, the predictability of tumor progression is stochastic and is difficult to predict. In the present study, we hypothesized to examine the key pathways that are dysregulated to promote epithelial-mesenchymal transition in serous ovarian carcinoma. Examination of these steps would help to identify ascitic fluid with cells poised for metastasis or otherwise. We focused on examining the Akt2 expression, mainly because of its report as being overamplified in the aggressive variants of ovarian cancer, as well as TGFbeta-sensitivity of Akt2 that forms the key basis for metastasis initiation of most kinds of carcinoma. We obtained primary ovarian carcinoma samples as well as ascitic fluid and distantly metastatic ovarian carcinoma to examine the expression of Akt2. The results of the study demonstrated that in malignant exfoliated ovarian cancer cells, Smad4 expression was tremendously increased in the nuclei, suggesting nuclear translocation of Smad, which thereafter may have activated ZEB2, and thereafter genomically affected the expression of E-cadherin, myosin II, and vimentin, key components for initiating and sustaining metastasis. All of these may have been stimulated by increased cellular expression of Akt2 in metastatic variants of the serous ovarian carcinoma. The reliance on Akt2 and TGF beta signaling may also potentiate the case for Akt inhibitors or small molecule inhibitors of TGFbeta signaling like doxycycline as adjunct chemotherapy in serous ovarian carcinoma, especially the metastatic variants.