Novel Ultrastructural Insights into the Clear-Cell Carcinoma of the Pancreas: A Case Report.

Pancreatic cancer, most frequently as ductal adenocarcinoma (PDAC), is the third leading cause of cancer death. Clear-cell primary adenocarcinoma of the pancreas (CCCP) is a rare, aggressive, still poorly characterized subtype of PDAC. We report here a case of a 65-year-old male presenting with pancreatic neoplasia. A histochemical examination of the tumor showed large cells with clear and abundant intracytoplasmic vacuoles. The clear-cell foamy appearance was not related to the hyperproduction of mucins. Ultrastructural characterization with transmission electron microscopy revealed the massive presence of mitochondria in the clear-cell cytoplasm. The mitochondria showed disordered cristae and various degrees of loss of structural integrity. Immunohistochemistry staining for NADH dehydrogenase [ubiquinone] 1 alpha subcomplex, 4-like 2 (NDUFA4L2) proved specifically negative for the clear-cell tumor. Our ultrastructural and molecular data indicate that the clear-cell nature in CCCP is linked to the accumulation of disrupted mitochondria. We propose that this may impact on the origin and progression of this PDAC subtype.

Targeting PDGF signaling of cancer-associated fibroblasts blocks feedback activation of HIF-1α and tumor progression of clear cell ovarian cancer.

Ovarian clear cell carcinoma (OCCC) is a gynecological cancer with a dismal prognosis; however, the mechanism underlying OCCC chemoresistance is not well understood. To explore the intracellular networks associated with the chemoresistance, we analyze surgical specimens by performing integrative analyses that combine single-cell analyses and spatial transcriptomics. We find that a chemoresistant OCCC subpopulation with elevated HIF activity localizes mainly in areas populated by cancer-associated fibroblasts (CAFs) with a myofibroblastic phenotype, which is corroborated by quantitative immunostaining. CAF-enhanced chemoresistance and HIF-1α induction are recapitulated in co-culture assays, which show that cancer-derived platelet-derived growth factor (PDGF) contributes to the chemoresistance and HIF-1α induction via PDGF receptor signaling in CAFs. Ripretinib is identified as an effective receptor tyrosine kinase inhibitor against CAF survival. In the co-culture system and xenograft tumors, ripretinib prevents CAF survival and suppresses OCCC proliferation in the presence of carboplatin, indicating that combination of conventional chemotherapy and CAF-targeted agents is effective against OCCC.

The impact of lymphadenectomy on the survival outcomes of ovarian clear cell carcinoma: A retrospective study of the SEER database and Chinese registry.

BACKGROUND: Ovarian clear cell carcinoma (OCCC) is a rare pathological type of ovarian cancer with a poor prognosis, and lymphadenectomy is controversial in patients with OCCC. The objective of this study was to evaluate the impact of lymphadenectomy on the prognosis of patients with OCCC. METHODS: In this retrospective study, we collected data from the Surveillance, Epidemiology and End Results (SEER) database and institutional registries in China. The SEER cohort included 1777 women diagnosed with OCCC between 2010 and 2019, while the Chinese cohort included 199 women diagnosed between April 2004 and April 2021. Recurrence-free survival (RFS) and overall survival (OS) were studied using Kaplan-Meier curve and Cox regression analysis. We also employed propensity score matching (PSM) to adjust for baseline imbalances between the lymphadenectomy group and the no-lymphadenectomy group. RESULTS: Multivariate cox regression analysis showed that lymphadenectomy was not associated with better overall survival (OS) in either early (hazard ratio [HR] 0.84[0.50-1.43], p = 0.528) or advanced (HR 0.78[0.50-1.21], p = 0.270) patients in the SEER cohort after PSM. Additionally, in the Kaplan-Meier curve analysis, lymphadenectomy did not significantly improve OS in both early (p = 0.28) and advanced (p = 0.49) patients in the SEER cohort after PSM. Similarly, in the Chinese cohort, lymphadenectomy had no significant effect on OS (early p = 0.22; advanced p = 0.61) or RFS (early p = 0.18; advanced p = 0.83) in both early and advanced patients. CONCLUSION: In completely homogeneous groups, lymphadenectomy in women diagnosed with OCCC had no effect on either recurrence-free survival or overall survival compared to patients without lymphadenectomy.

Cell State of Origin Impacts Development of Distinct Endometriosis-Related Ovarian Carcinoma Histotypes.

Clear cell ovarian carcinoma (CCOC) and endometrioid ovarian carcinoma (ENOC) are ovarian carcinoma histotypes, which are both thought to arise from ectopic endometrial (or endometrial-like) cells through an endometriosis intermediate. How the same cell type of origin gives rise to two morphologically and biologically different histotypes has been perplexing, particularly given that recurrent genetic mutations are common to both and present in nonmalignant precursors. We used RNA transcription analysis to show that the expression profiles of CCOC and ENOC resemble those of normal endometrium at secretory and proliferative phases of the menstrual cycle, respectively. DNA methylation at the promoter of the estrogen receptor (ER) gene (ESR1) was enriched in CCOC, which could potentially lock the cells in the secretory state. Compared with normal secretory-type endometrium, CCOC was further defined by increased expression of cysteine and glutathione synthesis pathway genes and downregulation of the iron antiporter, suggesting iron addiction and highlighting ferroptosis as a potential therapeutic target. Overall, these findings suggest that while CCOC and ENOC arise from the same cell type, these histotypes likely originate from different cell states. This "cell state of origin" model may help to explain the presence of histologic and molecular cancer subtypes arising in other organs. SIGNIFICANCE: Two cancer histotypes diverge from a common cell of origin epigenetically locked in different cell states, highlighting the importance of considering cell state to better understand the cell of origin of cancer.

A phase 2 study of dasatinib in recurrent clear cell carcinoma of the ovary, fallopian tube, peritoneum or endometrium: NRG oncology/gynecologic oncology group study 0283.

OBJECTIVE: Gynecologic cancers are traditionally managed according to their presumed site of origin, without regard to the underlying histologic subtype. Clear cell histology is associated with chemotherapy refractoriness and poor survival. Mutations in SWI/SNF chromatin remodeling complex member ARID1A, which encodes for BAF250a protein, are common in clear cell and endometriosis-associated endometrioid carcinomas. High-throughput cell-based drug screening predicted activity of dasatinib, a tyrosine kinase inhibitor, in ARID1A-mutant clear cell carcinoma. METHODS: We conducted a phase 2 clinical trial of dasatinib 140 mg once daily by mouth in patients with recurrent or persistent ovarian and endometrial clear cell carcinoma. Patients with measurable disease were enrolled and then assigned to biomarker-defined populations based on BAF250a immunohistochemistry. The translational endpoints included broad next-generation sequencing to assess concordance of protein expression and treatment outcomes. RESULTS: Twenty-eight patients, 15 of whom had tumors with retained BAF250a and 13 with loss of BAF250a were evaluable for treatment response and safety. The most common grade 3 adverse events were anemia, fatigue, dyspnea, hyponatremia, pleural effusion, and vomiting. One patient had a partial response, eight (28%) had stable disease, and 15 (53.6%) had disease progression. Twenty-three patients had next-generation sequencing results; 13 had a pathogenic ARID1A alteration. PIK3CA mutations were more prevalent in ARID1A-mutant tumors, while TP53 mutations were more prevalent in ARID1A wild-type tumors. CONCLUSIONS: Dasatinib was not an effective single-agent treatment for recurrent or persistent ovarian and endometrial clear cell carcinoma. Studies are urgently needed for this rare gynecologic subtype.

Genomic profiling of ovarian clear cell carcinoma in Chinese patients reveals potential prognostic biomarkers for survival.

INTRODUCTION: Ovarian clear cell carcinoma (OCCC) has distinct clinical and molecular features and heterogeneous prognosis. Insights into the somatic genomic abnormalities of OCCC provide the basis for deeper understanding and potential therapeutic avenues. Herein, we performed extensive genomic profiling in Chinese patients to illustrate the mutation landscape and genetic prognostic biomarkers of OCCC. PATIENTS AND METHODS: We used targeted DNA sequencing on 61 OCCC cases with a panel of 520 cancer-related genes. Correlations between clinicopathological features and survival were evaluated. Nomogram-based models were constructed to predict progress-free survival (PFS). RESULTS: We detected 763 somatic mutations spanning 286 genes. The most frequent genetic alterations, ARID1A (49%) and PIK3CA (48%), were concurrently mutated. Comprehensive copy number alterations (CNAs) were identified in chromosomes 20q13.2 and 8q. Most (73.7%) patients harboured potentially targetable driver mutations. The mean and median tumour mutational burden were 7.0 and 3.0 mutations/Mb, respectively. Microsatellite instability (high) was identified in 8.2% of patients. Mutation of the base-excision repair pathway was significantly higher in patients of stage II/III/IV. ATM mutation was associated with platinum sensitivity (p < .05). Survival analysis identified chr8q CNAs in all patients, PIK3CA mutations in stage I patients and SWI/SNF complex (ARID1A and SMARCA4) mutations in stage II/III/IV patients as potential prognosticators (p < .05). Integration of genetic alterations (SWI/SNF complex mutations, ATM mutations and chr8q CNAs) improved the performance of a nomogram based on tumour stage and residual disease (concordance index 0.75 vs. 0.70, p < .05). CONCLUSIONS: We described somatic genomic alterations in Chinese OCCC patients and observed different genomic alterations between stage I and stage II/III/IV tumours. Genetic factors may supplement clinical factors in nomogram modelling for PFS prediction.Key MessagesWe performed extensive genomic profiling in a well-annotated cohort of 61 Chinese ovarian clear cell carcinoma (OCCC) patients.PIK3CA mutations were associated with worse overall survival (OS) in stage I OCCC, and SWI/SNF gene mutations were associated with improved OS in stage II/III/IV disease.We propose an easy-to-use nomogram using clinical factors (tumour stage and residual disease) and genetic alterations (SWI/SNF complex mutations, ATM mutations and chr8q CNAs) to predict the progress-free survival (PFS) of OCCC.

GATA3 expression in clear cell adenocarcinoma of the lower urinary tract: a potential diagnostic pitfall.

BACKGROUND: Clear cell adenocarcinoma of the lower urinary tract (CCACLUT) is a rare primary malignant neoplasm with heterogenous morphology. There is a paucity of data in the literature regarding its immunohistochemical profile. METHODS: The immunohistochemical features (extent and intensity) of a multinational cohort of CCACLUT were evaluated with comparison between clear cell adenocarcinoma of the female genital tract (CCACFGT, tissue microarray) and nephrogenic adenoma (NA). RESULTS: 33 CCACLUT (24 female, 9 male; mean age 59 years) were collected. CCACLUT most commonly arose from the urinary bladder (26/33, 78%), particularly from the trigone (10/33, 30.3%) followed by the urethra (8/33, 22%). All 12 NA cases were located at the urinary bladder, whereas the most common CCACFGT location was the ovary (29/56, 52%). None of the CCACLUT patients had, intestinal metaplasia, NA, or urothelial carcinoma. One patient had concurrent endometriosis of the sigmoid colon. Most frequently observed morphology in CCACLUT was papillary/tubulocystic (9/3; 27.3%), followed by papillary/tubular (6/33; 18.2%) and papillary/solid (5/33; 15.2%). GATA3 expression was significantly higher in CCACLUT (18/33, 54.5%) and NA (6/12, 50%), when compared to CCACFGT cases 6/56, 11.7%)(p = 0.001 and p = 0.022, respectively). The extent of GATA3 was significantly higher in CCACLUT group (19.2 ± 16.6%) than the other groups (9.6 ± 22.5% in NA and 2.6 ± 9% in CCACFGT group) (p = 0.001). 4/33 patients (12.1) had weak, 10/33 patients (30.3%) had moderate, and 4/33 patients (12.1%) had strong GATA3 intensity in CCACLUT group. In NA group, one patient (8.3%, 1/12) had weak, one patient (8.3%, 1/12) had moderate and 4 patients (33.3%, 4/12) had strong GATA3 intensity. Most cases (CCACLUT 29/33, 88%; NA 11/12, 92%; CCACFGT 46/56, 82.1%) had positive Napsin A expression, by which CCACLUT had significantly more cases with Napsin A expression (p = 0.034). p63 was consistently negative in all cases (30/33 (91.9%) CCACLUT; 12/12 (100%) NA; 42/56 (75%) CCACFGT. Ki67 (MIB) proliferation index was significantly higher in CCACLUT group (54.6 ± 21%) when compared to NA group (4.5 ± 2.7%) and CCACFGT group (35.5 ± 25.8%) (p = 0.001). CONCLUSION: CCACLUT has consistent GATA3 expression, which may cause challenge in the diagnosis of urothelial carcinoma but can be used to distinguish CCACLUT from CCACFGT.

Endometriosis-Associated Mesenchymal Stem Cells Support Ovarian Clear Cell Carcinoma through Iron Regulation.

Ovarian clear cell carcinoma (OCCC) is a deadly and treatment-resistant cancer, which arises within the unique microenvironment of endometriosis. In this study, we identified a subset of endometriosis-derived mesenchymal stem cells (enMSC) characterized by loss of CD10 expression that specifically support OCCC growth. RNA sequencing identified alterations in iron export in CD10-negative enMSCs and reciprocal changes in metal transport in cocultured OCCC cells. CD10-negative enMSCs exhibited elevated expression of iron export proteins hephaestin and ferroportin and donate iron to associated OCCCs, functionally increasing the levels of labile intracellular iron. Iron is necessary for OCCC growth, and CD10-negative enMSCs prevented the growth inhibitory effects of iron chelation. In addition, enMSC-mediated increases in OCCC iron resulted in a unique sensitivity to ferroptosis. In vitro and in vivo, treatment with the ferroptosis inducer erastin resulted in significant death of cancer cells grown with CD10-negative enMSCs. Collectively, this work describes a novel mechanism of stromal-mediated tumor support via iron donation. This work also defines an important role of endometriosis-associated MSCs in supporting OCCC growth and identifies a critical therapeutic vulnerability of OCCC to ferroptosis based on stromal phenotype. SIGNIFICANCE: Endometriosis-derived mesenchymal stem cells support ovarian clear cell carcinoma via iron donation necessary for cancer growth, which also confers sensitivity to ferroptosis-inducing therapy.

Retinol dehydrogenase 10 contributes to cancer stemness and intracellular carbohydrate storage in ovarian clear cell carcinomas.

BACKGROUND: Ovarian clear cell carcinomas (OCCCs) have been recurrent and refractory among the present treatments, so novel therapeutics are urgently needed. OBJECTIVE: The present study accumulates the proof of concept to examine the feasibility of RDH10 as a therapeutic target for treating OCCCs. METHODS: Immunohistochemically, RDH10 expression was evaluated in 111 primary epithelial ovarian cancers, including 55 OCCCs, 31 ovarian endometrioid carcinomas and 25 ovarian serous carcinomas. The spherogenecity provoked by RDH10 was evaluated in OCCC cells. To analyze whether RDH10 promotes carbohydrate storage via the vitamin A-gluconeogenesis pathway, phosphoenolpyruvate carboxykinase 1 (PCK1) protein levels and intracellular carbohydrate content were measured in response to modified RDH10 expression. RESULTS: Abundant RDH10 was expressed specifically in OCCCs. RDH10 promoted spherogenecity and intracellular carbohydrate storage via modulation of PCK1 expression in OCCC cells. CONCLUSIONS: In the present study, abundant RDH10 contributed to cancer cell stemness and intracellular carbohydrate storage in OCCCs. RDH10 is a potentially, new therapeutic candidate for treating OCCC cases.

The worsening impact of programmed cell death ligand 1 in ovarian clear cell carcinomas.

PURPOSE: To investigate the clinical significance of programmed cell death ligand 1 (PD-L1) expression in ovarian clear cell carcinoma (CCC). MATERIALS AND METHODS: Patients with CCC who underwent primary surgery at our hospital between 1984 and 2014 were enrolled in this study. PD-L1 and mismatch repair (MMR) protein expression in tumor cells, tumor-infiltrating lymphocytes (TILs), including cluster of differentiation (CD) 8, CD4, forkhead box P3 (FOXP3), programmed cell death 1 (PD-1), and BAF250a, were evaluated using immunohistochemistry. The association between PD-L1 expression, clinicopathological features, prognosis, and expression of several proteins was investigated. RESULTS: Of the 125 patients with CCC, 17 had negative PD-L1 and 108 had positive PD-L1. Patients with positive PD-L1 expression showed a lower response to chemotherapy (p = 0.01). In addition, patients with positive PD-L1 showed worse progression-free survival (PFS, p = 0.01) and overall survival (OS, p = 0.01) than that in patients with negative PD-L1 expression. Multivariate analyses for PFS and OS showed that PD-L1 expression was an independent prognostic factor for PFS (hazard ratio [HR] 7.81, p < 0.01) and OS (HR 12.90, p < 0.01). PD-L1 expression was not associated with the expression of several TILs or proteins. CONCLUSION: The expression of PD-L1 was related to a lower response to chemotherapy and worse prognosis in CCC. These results may be useful for the development of new treatments.

Lipophagy-ICAM-1 pathway associated with fatty acid and oxygen deficiencies is involved in poor prognoses of ovarian clear cell carcinoma.

BACKGROUND: Serum starvation and hypoxia (SSH) mimics a stress condition in tumours. We have shown that intercellular adhesion molecule-1 (ICAM-1) protein is synergistically expressed in ovarian clear cell carcinoma (CCC) cells under SSH in response to an insufficient supply of fatty acids (FAs). This ICAM-1 expression is responsible for resistance against the lethal condition, thereby promoting tumour growth. However, the underlying mechanisms that link SSH-driven ICAM1 gene expression to impaired FA supply and its clinical relevance are unclear. METHODS: The underlying mechanisms of how FA deficiency induces ICAM-1 expression in cooperation with hypoxia were analysed in vitro and in vivo. Clinical significance of CCC cell-derived ICAM-1 and the mechanism associated with the transcriptional synergism were also investigated. RESULTS: ICAM-1 expression was mediated through lipophagy-driven lipid droplet degradation, followed by impaired FA-lipid droplet flow. Lipophagy induced ICAM1 expression through stabilisation of NFκB binding to the promoter region via Sam68 and hTERT. Analyses of clinical specimens revealed that expression of ICAM-1 and LC3B, an autophagy marker associated with lipophagy, significantly correlated with poor prognoses of CCC. CONCLUSIONS: The lipophagy-ICAM-1 pathway induced under a tumour-like stress conditions contributes to CCC progression and is a potential therapeutic target for this aggressive cancer type.

OSI-906 restores the sensitivity of ovarian clear cell carcinoma to cisplatin by targeting the IGF1R/AKT pathway.

Among the various histologic subtypes of ovarian cancers (OCs), ovarian clear cell carcinoma (OCCC) represents a great challenge due to its disease aggressiveness and resistance to chemotherapy. IGF1 is overexpressed in epithelial ovarian cancer (EOC), and IGF1 pathway activation is related to the chemoresistance of various cancers. In this study, we found that the expression level of IGF1 was higher in OCCC than in the most common type of OC, high-grade serous adenocarcinoma (HGSC). Then, we investigated the role of IGF1 pathway activation in the progression of OCCC, observing that activation of the IGF1 pathway using IGF1 promoted the proliferation and migration of ES2 cells, while inactivation of the IGF1 pathway using the selective IGF1R inhibitor OSI-906 reversed the alteration mediated by IGF1. Based on the role of the IGF1 pathway in cancer chemoresistance, we proposed that OSI-906 may restore the sensitivity of OCCC to cisplatin. We first validated that IGF1 increased the IC50 value of cisplatin in ES2 cells, while OSI-906 decreased it. Then we confirmed that IGF1 decreased the apoptosis rate of ES2 cells induced by cisplatin, while OSI-906 increased it. Finally, we conducted animal experiments to investigate whether OSI-906 helps cisplatin control the growth of OCCC. As expected, OSI-906 increased the effect of cisplatin in attenuating the growth of OCCC in vivo. Therefore, we conclude that using OSI-906 may be an effective method to restore the sensitivity of OCCC to cisplatin by targeting the IGF1R/AKT pathway.

Prognostic and Theranostic Biomarkers in Ovarian Clear Cell Carcinoma.

In this study, we aimed to test whether prognostic biomarkers can achieve a clinically relevant stratification of patients with stage I ovarian clear cell carcinoma (OCCC) and to survey the expression of 10 selected actionable targets (theranostic biomarkers) in stage II to IV cases. From the population-based Alberta Ovarian Tumor Type study, 160 samples of OCCC were evaluated by immunohistochemistry and/or silver-enhanced in situ hybridization for the status of 5 prognostic (p53, p16, IGF2BP3, CCNE1, FOLR1) and 10 theranostic biomarkers (ALK, BRAF V600E, ERBB2, ER, MET, MMR, PR, ROS1, NTRK1-3, VEGFR2). Kaplan-Meier survival analyses were performed. Cases with abnormal p53 or combined p16/IFG2BP3 abnormal expression identified a small subset of patients (6/54 cases) with stage I OCCC with an aggressive course (5-yr ovarian cancer-specific survival of 33.3%, compared with 91.5% in the other stage I cases). Among theranostic targets, ERBB2 amplification was present in 11/158 (7%) of OCCC, while MET was ubiquitously expressed in OCCC similar to a variety of normal control tissues. ER/PR showed a low prevalence of expression. No abnormal expression was detected for any of the other targets. We propose a combination of 3 biomarkers (p53, p16, IGF2BP3) to predict prognosis and the potential need for adjuvant therapy for patients with stage I OCCC. This finding requires replication in larger cohorts. In addition, OCCC could be tested for ERBB2 amplification for inclusion in gynecological basket trials targeting this alteration.

The splicing factor DHX38/PRP16 is required for ovarian clear cell carcinoma tumorigenesis, as revealed by a CRISPR-Cas9 screen.

Certain cancers, such as ovarian clear cell carcinoma (OCCC), display high levels of genetic variation between patients, making it difficult to develop effective therapies. In order to identify novel genes critical to OCCC growth, we carried out a comprehensive CRISPR-Cas9 knockout screen against cell growth using an OCCC cell line and a normal ovarian surface epithelium cell line. We identified the gene encoding DHX38/PRP16, an ATP-dependent RNA helicase involved in splicing, as critical for the growth and tumorigenesis of OCCC. DHX38/PRP16 knockdown in OCCC cells, but not normal cells, induces apoptosis and impairs OCCC tumorigenesis in a mouse model. Our results suggest that DHX38/PRP16 may play a role in OCCC tumorigenesis and could potentially be a promising therapeutic target.

Targeting the IRE1α/XBP1 Endoplasmic Reticulum Stress Response Pathway in ARID1A-Mutant Ovarian Cancers.

The SWI/SNF chromatin-remodeling complex is frequently altered in human cancers. For example, the SWI/SNF component ARID1A is mutated in more than 50% of ovarian clear cell carcinomas (OCCC), for which effective treatments are lacking. Here, we report that ARID1A transcriptionally represses the IRE1α-XBP1 axis of the endoplasmic reticulum (ER) stress response, which confers sensitivity to inhibition of the IRE1α-XBP1 pathway in ARID1A-mutant OCCC. ARID1A mutational status correlated with response to inhibition of the IRE1α-XBP1 pathway. In a conditional Arid1aflox/flox/Pik3caH1047R genetic mouse model, Xbp1 knockout significantly improved survival of mice bearing OCCCs. Furthermore, the IRE1α inhibitor B-I09 suppressed the growth of ARID1A-inactivated OCCCs in vivo in orthotopic xenograft, patient-derived xenograft, and the genetic mouse models. Finally, B-I09 synergized with inhibition of HDAC6, a known regulator of the ER stress response, in suppressing the growth of ARID1A-inactivated OCCCs. These studies define the IRE1α-XBP1 axis of the ER stress response as a targetable vulnerability for ARID1A-mutant OCCCs, revealing a promising therapeutic approach for treating ARID1A-mutant ovarian cancers. SIGNIFICANCE: These findings indicate that pharmacological inhibition of the IRE1α-XBP1 pathway alone or in combination with HDAC6 inhibition represents an urgently needed therapeutic strategy for ARID1A-mutant ovarian cancers.

Preclinical Activity of Plitidepsin Against Clear Cell Carcinoma of the Ovary.

BACKGROUND/AIM: To evaluate the antitumor effects of Plitidepsin against clear cell carcinoma (CCC) of the ovary. MATERIALS AND METHODS: The expression of eEF1A2 in ovarian cancer was assessed by immunohistochemistry. Using ovarian CCC cell lines, the antitumor effect of Plitidepsin was assessed both in vitro and in vivo. By over-expressing or knocking down the eEF1A2 expression, we investigated the role of eEF1A2 in the sensitivity of CCC cells to Plitidepsin. RESULTS: Immunoreactivity to eEF1A2 was observed in 76.2% of CCC, which was significantly higher than other histological subtypes of ovarian cancer. Plitidepsin exhibited significant antitumor activity toward chemonaive and chemoresistant CCC cells both in vitro and in vivo. Ectopic expression of eEF1A2 in CCC cells resulted in increased sensitivity to Plitidepsin. In contrast, eEF1A2 knockdown decreased sensitivity of CCC cells to plitidepsin. CONCLUSION: Plitidepsin, a novel anti-cancer agent that targets eEF1A2, may be a promising agent for treating ovarian CCC.

LncRNA GAS5 inhibits the proliferation and invasion of ovarian clear cell carcinoma via the miR-31-5p/ARID1A axis.

To investigate the role of the lncRNA growth arrest special 5 (GAS5) in ovarian clear cell carcinoma (OCCC), we measured the expression of GAS5 and miR-31-5p in OCCC tissue samples and OCCC cell lines using RT-qPCR. MTT and colony formation assays were used to measure cell viability and colony formation ability. Cell invasion was determined by Transwell assays. The binding between GAS5 and miR-31-5p as well as miR-31-5p and ARID1A was determined by dual-luciferase reporter assays. The ARID1A protein levels were detected using western blotting. Kaplan-Meier curves were used for the analysis of the 5-year survival rate of patients with OCCC. GAS5 and ARID1A levels were significantly decreased, while miR-31-5p levels were strongly elevated in the OCCC tissues and cell lines. Patients with lower GAS5/ARID1A levels had shorter overall survival times. Overexpression of GAS5 or inhibition of miR-31-5p suppressed cell viability and invasion of OCCC cells and upregulated the protein levels of ARID1A. Moreover, overexpression of miR-31-5p reversed the effects of overexpression of GAS5. Cotransfection with pcDNA3.1-GAS5 and miR-31-5p inhibitor led to the lowest cell viability and cell invasion rates. A dual-luciferase reporter assay was performed to confirm the target relationship between GAS5 and miR-31-5p, as well as between miR-31-5p and ARID1A. LncRNA GAS5 inhibited cell viability and invasion of OCCC through activation of ARID1A by sponging miR-31-5p.

CCNE1 Is a Putative Therapeutic Target for ARID1A-Mutated Ovarian Clear Cell Carcinoma.

BACKGROUND: Ovarian clear cell carcinoma (OCCC) is resistant to platinum chemotherapy and is characterized by poor prognosis. Today, the use of poly (ADP-ribose) polymerase (PARP) inhibitor, which is based on synthetic lethality strategy and characterized by cancer selectivity, is widely used for new types of molecular-targeted treatment of relapsed platinum-sensitive ovarian cancer. However, it is less effective against OCCC. METHODS: We conducted siRNA screening to identify synthetic lethal candidates for the ARID1A mutation; as a result, we identified Cyclin-E1 (CCNE1) as a potential target that affects cell viability. To further clarify the effects of CCNE1, human OCCC cell lines, namely TOV-21G and KOC7c (ARID1A mutant lines), and RMG-I and ES2 (ARID1A wild type lines) were transfected with siRNA targeting CCNE1 or a control vector. RESULTS: Loss of CCNE1 reduced proliferation of the TOV-21G and KOC7c cells but not of the RMG-I and ES2 cells. Furthermore, in vivo interference of CCNE1 effectively inhibited tumor cell proliferation in a xenograft mouse model. CONCLUSION: This study showed for the first time that CCNE1 is a synthetic lethal target gene to ARID1A-mutated OCCC. Targeting this gene may represent a putative, novel, anticancer strategy in OCCC treatment.

PD-L1 expression and immune stromal features in HPV-independent cervical adenocarcinoma.

AIMS: Human papilloma virus (HPV)-independent cervical adenocarcinoma (CA) is usually diagnosed at an advanced stage, while the therapeutic options are limited. Therefore, effective treatment options are required. The programmed cell death 1 (PD-1) inhibitor pembrolizumab has been approved for the treatment of patients with recurrent or metastatic cervical squamous cell carcinoma expressing PD-ligand 1 (PD-L1). However, no data regarding PD-L1 expression in HPV-independent CA are available. Thus, we evaluated the association between PD-L1 expression and the clinicopathological characteristics and survival of patients with HPV-independent CA. METHODS: We evaluated PD-L1, mismatch repair (MMR) protein expression and the immune stromal features of 44 patients with HPV-independent CA. PD-L1 expression was defined as a combined positive score (CPS) ≥1 and a tumour proportion score (TPS) ≥1%. RESULTS: PD-L1 expression was observed in 14 cases (31.8%) with CPS ≥1 and 12 cases (27.3%) with TPS ≥1%. PD-L1 expression, based on either the CPS or the TPS, was associated with a high tumour-infiltrating lymphocyte percentage (CPS = P < 0.001; TPS = P < 0.001). Patients with a PD-L1 CPS ≥1 showed worse progression-free survival and overall survival than PD-L1-negative patients (P = 0.004 and P = 0.023, respectively). Forty-two cases demonstrated intact MMR expression and two cases demonstrated loss of MSH2/MSH6. CONCLUSIONS: Our data demonstrated that PD-L1 was expressed in HPV-independent CA, especially in clear cell carcinoma, and that PD-L1 expression is a negative prognostic marker. Our data support the role of PD-L1 in HPV-independent CA and its potential as an immunotherapeutic target.

Expression of estrogen-related receptors in ovarian cancer and impact on survival.

PURPOSE: This study further approaches the role of estrogen-related receptors (ERRs) in ovarian cancer. Protein expression of ERRα, ERRß and ERRγ in ovarian cancer was assessed and was correlated with ovarian cancer markers, steroid hormone receptors and cancer-associated genes. Additionally, we examined to what extent expression of ERRs affects survival of ovarian cancer patients. METHODS: For this purpose, we established a tissue microarray from 208 ovarian cancer patients and performed immunohistochemical analyses of the mentioned proteins. RESULTS: ERRα and ERRγ protein could be detected at different levels in more than 90% of all ovarian cancer tissues, whereas expression of ERRß was observed in 82.2% of the cases. ERRα was found to positively correlate with ovarian cancer marker CEA (p < 0.005) and ERRγ correlated with ERα (p < 0.001). Univariate survival analyses revealed that ERRα expression did not affect overall (OS) or progression-free survival (PFS) of ovarian cancer patients. In contrast, higher expression of ERRß in serous ovarian cancers was found to lead to a significantly decreased OS (p < 0.05). The strongest impact on survival was exhibited by ERRγ. Lower expression of this receptor in women with serous ovarian cancers indicated significantly increased OS compared to those with higher levels of ERRγ (p < 0.05). Multivariate survival analyses revealed ERRγ as an independent prognostic marker regarding OS of patients with serous ovarian cancer. CONCLUSION: Our data demonstrating that ERR proteins are frequently expressed in ovarian cancer and high levels of ERRß and ERRγ significantly decreased OS of serous ovarian cancer patients suggest that these proteins might be interesting therapy targets in this cancer entity.