Impact of Cold Ischemia on the Stability of 1H-MRS-Detected Metabolic Profiles of Ovarian Cancer Specimens.

Proton magnetic resonance spectroscopy (1H-MRS) of surgically collected tumor specimens may contribute to investigating cancer metabolism and the significance of the "total choline" (tCho) peak (3.2 ppm) as malignancy and therapy response biomarker. To ensure preservation of intrinsic metabolomic information, standardized handling procedures are needed. The effects of time to freeze (cold ischemia) were evaluated in (a) surgical epithelial ovarian cancer (EOC) specimens using high-resolution (HR) 1H-MRS (9.4 T) of aqueous extracts and (b) preclinical EOC samples (xenografts in SCID mice) investigated by in vivo MRI-guided 1H-MRS (4.7 T) and by HR-1H-MRS (9.4 T) of tumor extracts or intact fragments (using magic-angle-spinning (MAS) technology). No significant changes were found in the levels of 27 of 29 MRS-detected metabolites (including the tCho profile) in clinical specimens up to 2 h cold ischemia, besides an increase in lysine and a decrease in glutathione. EOC xenografts showed a 2-fold increase in free choline within 2 h cold ischemia, without further significant changes for any MRS-detected metabolite (including phosphocholine and tCho) up to 6 h. At shorter times (≤1 h), HR-MAS analyses showed unaltered tCho components, along with significant changes in lactate, glutamate, and glutamine. Our results support the view that a time to freeze of 1 h represents a safe threshold to ensure the maintenance of a reliable tCho profile in EOC specimens.

Integration of MRI and MRS approaches to monitor molecular imaging and metabolomic effects of trabectedin on a preclinical ovarian cancer model.

Although several drugs are available to treat recurrences of human epithelial ovarian cancer (EOC), clinical responses often remain short lived and lead to only marginal improvements in patients' survival. One of the new drugs proposed for recurrent platinum-resistant EOC patients is trabectedin (Trab), a marine-derived antitumor agent initially isolated from the tunicate Ecteinascidia turbinata and currently produced synthetically. Predictive biomarkers of therapy response to this drug and the potential use of non-invasive functional MRI and MRS approaches for an early assessment of Trab efficacy have not yet been evaluated, although they might be relevant for improving the clinical management of EOC patients. In the present work we combined functional and spectroscopic magnetic resonance technologies, such as in vivo diffusion-weighted MRI and 1 H MRS, with ex vivo high resolution MRS (HR-MRS) metabolomic analyses, with the aim of identifying new pharmacodynamic markers of Trab effectiveness on well characterized, highly aggressive human SKOV3.ip (a HER2-enriched cell variant derived from SKOV3 cells) EOC xenografts. In vivo treatment with Trab (three consecutive weekly 0.2 mg/kg i.v. injections) resulted in the following: (1) a significant reduction of in vivo tumor growth, along with the formation in cancer lesions of diffuse hyper-intense areas detected by T2 -weighted MRI and attributed to necrosis, in agreement with histopathology findings; (2) significant increases in the apparent diffusion coefficient mean and median values versus saline-treated control tumors; and (3) a significant reduction in the choline-containing metabolites' signal detected by quantitative in vivo MRS. Multivariate and quantitative HR-MRS analyses on ex vivo tissue samples revealed Trab-induced alterations in phospholipid and glucose metabolism identified as a decrease in phosphocholine and an increase in lactate. Collectively, these data identify Trab-induced functional MRI and MRS alterations in EOC models as a possible basis for further developments of these non-invasive imaging methods to improve the clinical management of EOC patients.

One-Carbon Metabolism: Biological Players in Epithelial Ovarian Cancer.

Metabolism is deeply involved in cell behavior and homeostasis maintenance, with metabolites acting as molecular intermediates to modulate cellular functions. In particular, one-carbon metabolism is a key biochemical pathway necessary to provide carbon units required for critical processes, including nucleotide biosynthesis, epigenetic methylation, and cell redox-status regulation. It is, therefore, not surprising that alterations in this pathway may acquire fundamental importance in cancer onset and progression. Two of the major actors in one-carbon metabolism, folate and choline, play a key role in the pathobiology of epithelial ovarian cancer (EOC), the deadliest gynecological malignancy. EOC is characterized by a cholinic phenotype sustained via increased activity of choline kinase alpha, and via membrane overexpression of the alpha isoform of the folate receptor (FRα), both of which are known to contribute to generating regulatory signals that support EOC cell aggressiveness and proliferation. Here, we describe in detail the main biological processes associated with one-carbon metabolism, and the current knowledge about its role in EOC. Moreover, since the cholinic phenotype and FRα overexpression are unique properties of tumor cells, but not of normal cells, they can be considered attractive targets for the development of therapeutic approaches.

Development and validation of a microRNA-based signature (MiROvaR) to predict early relapse or progression of epithelial ovarian cancer: a cohort study.

BACKGROUND: Risk of relapse or progression remains high in the treatment of most patients with epithelial ovarian cancer, and development of a molecular predictor could be a valuable tool for stratification of patients by risk. We aimed to develop a microRNA (miRNA)-based molecular classifier that can predict risk of progression or relapse in patients with epithelial ovarian cancer. METHODS: We analysed miRNA expression profiles in three cohorts of samples collected at diagnosis. We used 179 samples from a Multicenter Italian Trial in Ovarian cancer trial (cohort OC179) to develop the model and 263 samples from two cancer centres (cohort OC263) and 452 samples from The Cancer Genome Atlas epithelial ovarian cancer series (cohort OC452) to validate the model. The primary clinical endpoint was progression-free survival, and we adapted a semi-supervised prediction method to the miRNA expression profile of OC179 to identify miRNAs that predict risk of progression. We assessed the independent prognostic role of the model using multivariable analysis with a Cox regression model. FINDINGS: We identified 35 miRNAs that predicted risk of progression or relapse and used them to create a prognostic model, the 35-miRNA-based predictor of Risk of Ovarian Cancer Relapse or progression (MiROvaR). MiROvaR was able to classify patients in OC179 into a high-risk group (89 patients; median progression-free survival 18 months [95% CI 15-22]) and a low-risk group (90 patients; median progression-free survival 38 months [24-not estimable]; hazard ratio [HR] 1·85 [1·29-2·64], p=0·00082). MiROvaR was a significant predictor of progression in the two validation sets (OC263 HR 3·16, 95% CI 2·33-4·29, p<0·0001; OC452 HR 1·39, 95% CI 1·11-1·74, p=0·0047) and maintained its independent prognostic effect when adjusted for relevant clinical covariates using multivariable analyses (OC179: adjusted HR 1·48, 95% CI 1·03-2·13, p=0·036; OC263: adjusted HR 3·09 [2·24-4·28], p<0·0001; and OC452: HR 1·41 [1·11-1·79], p=0·0047). INTERPRETATION: MiROvaR is a potential predictor of epithelial ovarian cancer progression and has prognostic value independent of relevant clinical covariates. MiROvaR warrants further investigation for the development of a clinical-grade prognostic assay. FUNDING: AIRC and CARIPLO Foundation.

MiR-506 inhibits multiple targets in the epithelial-to-mesenchymal transition network and is associated with good prognosis in epithelial ovarian cancer.

Extensive investigations have shown that miRNAs are important regulators of epithelial-to-mesenchymal transition (EMT), mainly targeting the transcriptional repressors of E-cadherin (E-cad). Less is known about the post-transcriptional regulation of vimentin or N-cadherin (N-cad) in EMT. Our previous study identified miR-506 as a key EMT inhibitor through directly targeting the E-cad transcriptional repressor SNAI2. In this study, we provide evidence that miR-506 simultaneously suppresses vimentin and N-cad. The knockdown of vimentin using siRNA reversed EMT, suppressed cell migration and invasion, and increased E-cad expression on the cell membrane in epithelial ovarian cancer (EOC) cells. In a set of tissue microarrays that included 204 EOCs of all major subtypes (eg serous, endometrioid, clear cell, and mucinous), miR-506 was positively correlated with E-cad and negatively correlated with vimentin and N-cad in all subtypes of EOC. A high level of miR-506 was positively associated with early FIGO stage and longer survival in EOC. Introduction of miR-506, mediated by nanoparticle delivery, in EOC orthotopic mouse models resulted in decreased vimentin, N-cad, and SNAI2 expression and increased E-cad expression; it also suppressed the dissemination of EOC cells. Thus, miR-506 represents a new class of miRNA that regulates both E-cad and vimentin/N-cad in the suppression of EMT and metastasis.

Key nodes of a microRNA network associated with the integrated mesenchymal subtype of high-grade serous ovarian cancer.

Metastasis is the main cause of cancer mortality. One of the initiating events of cancer metastasis of epithelial tumors is epithelial-to-mesenchymal transition (EMT), during which cells dedifferentiate from a relatively rigid cell structure/morphology to a flexible and changeable structure/morphology often associated with mesenchymal cells. The presence of EMT in human epithelial tumors is reflected by the increased expression of genes and levels of proteins that are preferentially present in mesenchymal cells. The combined presence of these genes forms the basis of mesenchymal gene signatures, which are the foundation for classifying a mesenchymal subtype of tumors. Indeed, tumor classification schemes that use clustering analysis of large genomic characterizations, like The Cancer Genome Atlas (TCGA), have defined mesenchymal subtype in a number of cancer types, such as high-grade serous ovarian cancer and glioblastoma. However, recent analyses have shown that gene expression-based classifications of mesenchymal subtypes often do not associate with poor survival. This "paradox" can be ameliorated using integrated analysis that combines multiple data types. We recently found that integrating mRNA and microRNA (miRNA) data revealed an integrated mesenchymal subtype that is consistently associated with poor survival in multiple cohorts of patients with serous ovarian cancer. This network consists of 8 major miRNAs and 214 mRNAs. Among the 8 miRNAs, 4 are known to be regulators of EMT. This review provides a summary of these 8 miRNAs, which were associated with the integrated mesenchymal subtype of serous ovarian cancer.

Activated leukocyte cell adhesion molecule soluble form: a potential biomarker of epithelial ovarian cancer is increased in type II tumors.

Activated leukocyte cell adhesion molecule (ALCAM) is involved in cell-cell interactions in cancer. Shedding of its ectodomain by the metalloprotease ADAM17/TACE generates a soluble form (sALCAM). Here, we show that serum sALCAM levels were significantly higher in epithelial ovarian cancer (EOC) (p < 0.005) than in controls. The performance of sALCAM as classifier, tested by receiver operating characteristic curve, resulted in an area under the curve (AUC) of 0.8067. Serum sALCAM levels showed direct correlation with Carbohydrate Antigen-125 (CA125/MUC16). Moreover, significantly higher levels were found in type II tumors, even in stage I/II, suggesting that elevated sALCAM is an early feature of aggressive EOC. In addition, sALCAM levels were higher in ascites than in sera, suggesting local processing of ALCAM in the peritoneal cavity. In immunodeficient mice, intraperitoneally implanted with a human EOC cell line, human sALCAM progressively increased in serum and was even higher in the ascites. The biochemical characterization of the sALCAM in EOC sera and ascites, showed two predominant forms of approximately 95 and 65 kDa but no EOC-specific isoform. In addition, full-length transmembrane ALCAM but no soluble form was detected in tumor-derived exosomes found in ascites. Finally, in vitro invasion assays showed that inhibition of ADAM17/TACE activity decreased EOC invasive properties, while opposite effects were mediated by a sALCAM-Fc chimera and by an antibody interfering with ALCAM/ALCAM interactions. Altogether these data suggest that sALCAM is a marker of EOC, which correlates with more aggressive type II tumors, and that ADAM17/TACE activity and sALCAM itself mediate enhanced invasiveness.

Biological and clinical impact of membrane EGFR expression in a subgroup of OC patients from the phase IV ovarian cancer MITO-16A/MANGO-OV2A trial.

BACKGROUND: Validated prognostic biomarkers for anti-angiogenic therapy using the anti-VEGF antibody Bevacizumab in ovarian cancer (OC) patients are still an unmet clinical need. The EGFR can contribute to cancer-associated biological mechanisms in OC cells including angiogenesis, but its targeting gave disappointing results with less than 10% of OC patients treated with anti-EGFR compounds showing a positive response, likely due to a non adequate selection and stratification of EGFR-expressing OC patients. METHODS: EGFR membrane expression was evaluated by immunohistochemistry in a cohort of 310 OC patients from the MITO-16A/MANGO-OV2A trial, designed to identify prognostic biomarkers of survival in patients treated with first line standard chemotherapy plus bevacizumab. Statistical analyses assessed the association between EGFR and clinical prognostic factors and survival outcomes. A single sample Gene Set Enrichment-like and Ingenuity Pathway Analyses were applied to the gene expression profile of 195 OC samples from the same cohort. In an OC in vitro model, biological experiments were performed to assess specific EGFR activation. RESULTS: Based on EGFR-membrane expression, three OC subgroups of patients were identified being the subgroup with strong and homogeneous EGFR membrane localization, indicative of possible EGFR out/in signalling activation, an independent negative prognostic factor for overall survival of patients treated with an anti-angiogenic agent. This OC subgroup resulted statistically enriched of tumors of histotypes different than high grade serous lacking angiogenic molecular characteristics. At molecular level, among the EGFR-related molecular traits identified to be activated only in this patients' subgroup the crosstalk between EGFR with other RTKs also emerged. In vitro, we also showed a functional cross-talk between EGFR and AXL RTK; upon AXL silencing, the cells resulted more sensitive to EGFR targeting with erlotinib. CONCLUSIONS: Strong and homogeneous cell membrane localization of EGFR, associated with specific transcriptional traits, can be considered a prognostic biomarker in OC patients and could be useful for a better OC patients' stratification and the identification of alternative therapeutic target/s in a personalized therapeutic approach.

Characterisation of in vivo ovarian cancer models by quantitative 1H magnetic resonance spectroscopy and diffusion-weighted imaging.

Magnetic resonance imaging (MRI) and spectroscopy (MRS) offer powerful approaches for detecting physiological and metabolic alterations in malignancies and help investigate underlying molecular mechanisms. Research on epithelial ovarian carcinoma (EOC), the gynaecological malignancy with the highest death rate characterised by frequent relapse and onset of drug resistance, could benefit from application of these molecular imaging approaches. In this study, MRI/MRS were used to characterise solid tumour models obtained by subcutaneous (s.c.) or intraperitoneal (i.p.) implantation of human SKOV3.ip cells in severe combined immunodeficiency (SCID) mice. In vivo MRI/MRS, ex vivo magic-angle-spinning (MAS), and in vitro (1)H-NMR measurements were carried out at 4.7 T, 9.4 T, and 9.4/16.5 T, respectively. MRI evaluation was performed by T1-, T2-, and diffusion-weighted (DW) multislice spin-echo imaging. The in vivo (1)H spectra of all tumour models showed a prominent resonance of total choline-containing metabolites (tCho). Quantitative in vivo MRS of both i.p. and s.c. SKOV3.ip xenografts showed that the mean tCho content was in the 2.9-4.5 mM range, with a mean PCho/tCho ratio of 0.99 ± 0.01 [23 examinations, 14-34 days post injection (dpi)], in good agreement with ex vivo and in vitro analyses. Myo-inositol ranged between 11.7 and 17.0 mM, with a trend towards higher values in i.p. xenografts at 14-16 dpi. The average apparent diffusion coefficient (ADC) values of SKOV3.ip xenografts [1.64 ± 0.11 (n = 9, i.p.) and 1.58 ± 0.03 x10(-3) mm(2)/s (n = 7, s.c.)] were in agreement with values reported for tumours from patients with EOC, while the mean vascular signal fraction (VSF) was lower (≤ 4%), probably due to the more rapid growth of preclinical models. Both s.c. and i.p. xenografts are valuable preclinical models for monitoring biochemical and physiopathological changes associated with in vivo EOC tumour growth and response to therapy, which may serve as the basis for further clinical development of noninvasive MR approaches.

Impairment of RAD17 Functions by miR-506-3p as a Novel Synthetic Lethal Approach Targeting DNA Repair Pathways in Ovarian Cancer.

Epithelial ovarian cancer (EOC) remains the most lethal gynecological cancer and development of chemo-resistance is a major factor in disease relapse. Homologous recombination (HR) is a critical pathway for DNA double strand break repair and its deficiency is associated to a better response to DNA damage-inducing agents. Strategies to inhibit HR-mediated DNA repair is a clinical need to improve patients' outcome. MicroRNA (miRNAs) affect most of cellular processes including response to cancer treatment. We previously showed that miR-506-3p targets RAD51, an essential HR component. In this study we demonstrated that: i) another HR component, RAD17, is also a direct target of miR-506-3p and that it is involved in mediating miR-506-3p phenotypic effects; ii) the impairment of miR-506-3p binding to RAD17 3' UTR reverted the miR-506-3p induced platinum sensitization; iii) miR-506-3p/RAD17 axis reduces the ability of EOC cell to sense DNA damage, abrogates the G2/M cell cycle checkpoint thus delaying the G2/M cell cycle arrest likely allowing the entry into mitosis of heavily DNA-damaged cells with a consequent mitotic catastrophe; iv) RAD17 expression, regulated by miR-506-3p, is synthetically lethal with inhibitors of cell cycle checkpoint kinases Chk1 and Wee1 in platinum resistant cell line. Overall miR-506-3p expression may recapitulate a BRCAness phenotype sensitizing EOC cells to chemotherapy and helping in selecting patients susceptible to DNA damaging drugs in combination with new small molecules targeting DNA-damage repair pathway.

The deubiquitinase USP8 regulates ovarian cancer cell response to cisplatin by suppressing apoptosis.

The identification of therapeutic approaches to improve response to platinum-based therapies is an urgent need for ovarian carcinoma. Deubiquitinases are a large family of ubiquitin proteases implicated in a variety of cellular functions and may contribute to tumor aggressive features through regulation of processes such as proliferation and cell death. Among the subfamily of ubiquitin-specific peptidases, USP8 appears to be involved in modulation of cancer cell survival by still poorly understood mechanisms. Thus, we used ovarian carcinoma cells of different histotypes, including cisplatin-resistant variants with increased survival features to evaluate the efficacy of molecular targeting of USP8 as a strategy to overcome drug resistance/modulate cisplatin response. We performed biochemical analysis of USP8 activity in pairs of cisplatin-sensitive and -resistant cells and found increased USP8 activity in resistant cells. Silencing of USP8 resulted in decreased activation of receptor tyrosine kinases and increased sensitivity to cisplatin in IGROV-1/Pt1 resistant cells as shown by colony forming assay. Increased cisplatin sensitivity was associated with enhanced cisplatin-induced caspase 3/7 activation and apoptosis, a phenotype also observed in cisplatin sensitive cells. Increased apoptosis was linked to FLIPL decrease and cisplatin induction of caspase 3 in IGROV-1/Pt1 cells, cisplatin-induced claspin and survivin down-regulation in IGROV-1 cells, thereby showing a decrease of anti-apoptotic proteins. Immunohistochemical staining on 65 clinical specimens from advanced stage ovarian carcinoma indicated that 40% of tumors were USP8 positive suggesting that USP8 is an independent prognostic factor for adverse outcome when considering progression free survival as a clinical end-point. Taken together, our results support that USP8 may be of diagnostic value and may provide a therapeutic target to improve the efficacy of platinum-based therapy in ovarian carcinoma.

Pan-Cancer Analysis of Canonical and Modified miRNAs Enhances the Resolution of the Functional miRNAome in Cancer.

Epitranscriptomic studies of miRNAs have added a new layer of complexity to the cancer field. Although there is fast-growing interest in adenosine-to-inosine (A-to-I) miRNA editing and alternative cleavage that shifts miRNA isoforms, simultaneous evaluation of both modifications in cancer is still missing. Here, we concurrently profiled multiple miRNA modification types, including A-to-I miRNA editing and shifted miRNA isoforms, in >13,000 adult and pediatric tumor samples across 38 distinct cancer cohorts from The Cancer Genome Atlas and The Therapeutically Applicable Research to Generate Effective Treatments data sets. The differences between canonical miRNAs and the wider miRNAome in terms of expression, clustering, dysregulation, and prognostic standpoint were investigated. The combination of canonical miRNAs and modified miRNAs boosted the quality of clustering results, outlining unique clinicopathologic features among cohorts. Certain modified miRNAs showed opposite expression from their canonical counterparts in cancer, potentially impacting their targets and function. Finally, a shifted and edited miRNA isoform was experimentally validated to directly bind and suppress a unique target. These findings outline the importance of going beyond the well-established paradigm of one mature miRNA per miRNA arm to elucidate novel mechanisms related to cancer progression. SIGNIFICANCE: Modified miRNAs may act as cancer biomarkers and function as allies or antagonists of their canonical counterparts in gene regulation, suggesting the concurrent consideration of canonical and modified miRNAs can boost patient stratification.

Validation of MiROvaR, a microRNA-based predictor of early relapse in early stage epithelial ovarian cancer as a new strategy to optimise patients' prognostic assessment.

AIM: Early-stage epithelial ovarian cancer (eEOC) patients have a generally favorable prognosis but unpredictable recurrence. Accurate prediction of risk of relapse is still a major concern, essentially to avoid overtreatment. Our robust tissue-based miRNA signature named MiROvaR, predicting early EOC recurrence in mostly advanced-stage EOC patients, is here challenged in an independent cohort to extend its classifying ability in the early-stage EOC setting. METHODS: We retrospectively selected patients who underwent comprehensive surgical staging at our institution including stages from IA to IIB. miRNA expression profile was analysed in 89 cases and MiROvaR algorithm was applied using the previously validated cut-off for patients' classification. The primary endpoint was progression-free survival (PFS) at 5 years. Complete follow-up time (median = 112 months) was also considered as secondary analysis. RESULTS: MiROvaR was assessable on 87 cases (19 events of disease progression) and classified 68 (78%) low-risk and 19 (22%) high-risk patients. Recurrence rate at primary end-point was 39% for high-risk patients as compared to 9.5% for low-risk ones. Accordingly, their Kaplan-Meier PFS curves were significantly different at both primary and secondary analysis (p = 0.0006 and p = 0.03, respectively). While none of the prominent clinical variables had prognostic relevance, MiROvaR significantly predicted disease recurrence at the 5-year assessment (primary endpoint analysis; HR:5.43, 95%CI:1.82-16.1, p = 0.0024; AUC = 0.78, 95%CI:0.53-0.82) and at complete follow-up time (HR:2.67, 95%CI:1.04-6.8, p = 0.041; AUC:0.68, 95%CI:0.52-0.82). CONCLUSIONS: We validated MiROvaR performance in identifying at diagnosis eEOC patients' at higher risk of early relapse thus enabling selection of the most effective therapeutic approach.

Analysis of A Disintegrin and Metalloprotease 17 (ADAM17) Expression as a Prognostic Marker in Ovarian Cancer Patients Undergoing First-Line Treatment Plus Bevacizumab.

To find prognostic factors for advanced ovarian cancer patients undergoing first-line therapy with carboplatin, paclitaxel and bevacizumab, we investigated the expression of a disintegrin and metalloprotease 17 (ADAM17) in cancer tissues. ADAM17 has been involved in ovarian cancer development, progression and cell resistance to cisplatin. Tissue microarrays from 309 ovarian cancer patients enrolled in the MITO16A/MANGO-OV2 clinical trial were analyzed by immunohistochemistry for ADAM17 protein expression. Intensity and extent of staining were combined into a semi-quantitative visual grading system (H score) which was related to clinicopathological characteristics of cases and the clinical outcome of patients by univariate and multivariate Cox regression models. ADAM17 immunostaining was detected in most samples, mainly localized in the tumor cells, with variable intensity across the cohort. Kaplan-Meier survival curves, generated according to the best cut-off value for the ADAM17 H score, showed that high ADAM17 expression was associated with worse prognosis for PFS and OS. However, after the application of a shrinkage procedure to adjust for overfitting hazard ratio estimates, the ADAM17 value as prognostic factor was lost. As subgroup analysis suggested that ADAM17 expression could be prognostically relevant in cases with no residual disease at baseline, further studies in this patient category may be worth planning.

Prognostic Evidence of the miRNA-Based Ovarian Cancer Signature MiROvaR in Independent Datasets.

Epithelial ovarian cancer (EOC) remains the second most common cause of gynecological cancer deaths. To improve patients' outcomes, we still need reliable biomarkers of early relapse, of which external independent validation is a crucial process. Our previously established prognostic signature, MiROvaR, including 35 microRNAs (miRNA) able to stratify EOC patients for their risk of relapse, was challenged on a new independent cohort of 197 EOC patients included in the Pelvic Mass Study whose miRNA profile was made publically available, thus resulting in the only accessible database aside from the EOC TCGA collection. Following accurate data matrix adjustment to account for the use of different miRNA platforms, MiROvaR confirmed its ability to discriminate early relapsing patients. The model's original cutoff separated 156 (79.2%) high- and 41 (20.8%) low-risk patients with median progression free survival (PFS) of 16.3 months and not yet reached (NYR), respectively (hazard ratio (HR): 2.42-95% Confidence Interval (CI) 1.49-3.93; Log-rank p = 0.00024). The MiROvaR predictive accuracy (area under the curve (AUC) = 0.68; 95% Cl 0.57-0.79) confirms its prognostic value. This external validation in a totally independently collected, handled and profiled EOC cohort suggests that MiROvaR is a strong and reliable biomarker of EOC early relapse, warranting prospective validation.

MiREDiBase, a manually curated database of validated and putative editing events in microRNAs.

MicroRNAs (miRNAs) are regulatory small non-coding RNAs that function as translational repressors. MiRNAs are involved in most cellular processes, and their expression and function are presided by several factors. Amongst, miRNA editing is an epitranscriptional modification that alters the original nucleotide sequence of selected miRNAs, possibly influencing their biogenesis and target-binding ability. A-to-I and C-to-U RNA editing are recognized as the canonical types, with the A-to-I type being the predominant one. Albeit some bioinformatics resources have been implemented to collect RNA editing data, it still lacks a comprehensive resource explicitly dedicated to miRNA editing. Here, we present MiREDiBase, a manually curated catalog of editing events in miRNAs. The current version includes 3,059 unique validated and putative editing sites from 626 pre-miRNAs in humans and three primates. Editing events in mature human miRNAs are supplied with miRNA-target predictions and enrichment analysis, while minimum free energy structures are inferred for edited pre-miRNAs. MiREDiBase represents a valuable tool for cell biology and biomedical research and will be continuously updated and expanded at https://ncrnaome.osumc.edu/miredibase .

Choline kinase alpha impairment overcomes TRAIL resistance in ovarian cancer cells.

BACKGROUND: Choline kinase-α (ChoKα/CHKA) overexpression and hyper-activation sustain altered choline metabolism conferring the cholinic phenotype to epithelial ovarian cancer (OC), the most lethal gynecological tumor. We previously proved that CHKA down-modulation reduced OC cell aggressiveness and increased sensitivity to in vitro chemotherapeutics' treatment also affecting intracellular content of one-carbon metabolites. In tumor types other than ovary, methionine decrease was shown to increase sensitivity to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-receptor 2 triggering. These effects were suggestive of a potential role for ChoKα in regulating susceptibility to TRAIL cytokine. METHODS: The relationship between ChoKα/CHKA and TRAIL-receptor 2 (TRAIL-R2) expression was investigated in silico in OC patients' GEO datasets and in vitro in a panel of OC cell lines upon transient CHKA silencing (siCHKA). The effect of siCHKA on metabolites content was assessed by LC-MS. The triggered apoptotic signalling was studied following soluble-TRAIL or anti-TRAIL-R2 agonist antibody treatment. Lipid rafts were isolated by Triton X-100 fractionation. Preclinical ex vivo studies were performed in OC cells derived from patients' ascites using autologous PBLs as effectors and a bispecific anti-TRAIL-R2/anti-CD3 antibody as triggering agent. RESULTS: Here we demonstrate that siCHKA specifically overcomes resistance to TRAIL-mediated apoptosis in OC cells. Upon siCHKA we detected: a significant sensitization to caspase-dependent apoptosis triggered by both soluble TRAIL and anti-TRAIL-R2 agonist antibody, a specific increase of TRAIL-R2 expression and TRAIL-R2 relocation into lipid rafts. In siCHKA-OC cells the acquired TRAIL sensitivity was completely reverted upon recovery of ChoKα expression but, at variance of other tumor cell types, TRAIL sensitivity was not efficiently phenocopied by methionine deprivation. Of note, we were also able to show that siCHKA sensitized tumor cells derived ex vivo from OC patients' ascites to the cytotoxic activity of autologous lymphocytes redirected by a bispecific anti-TRAIL-R2/anti-CD3 antibody. CONCLUSIONS: Our findings suggest that ChoKα/CHKA impairment, by restoring drug-induced or receptor-mediated cell death, could be a suitable therapeutic strategy to be used in combination with chemotherapeutics or immunomodulators to improve OC patients' outcome.

c-FLIPL expression defines two ovarian cancer patient subsets and is a prognostic factor of adverse outcome.

The impairment of apoptotic pathways represents an efficient mechanism to promote chemoresistance in cancer cells. We previously showed that in epithelial ovarian cancer (EOC) cells, long isoform of cellular FLICE-inhibitory protein (c-FLIP(L)) accounts for apoptosis resistance in a context of functional p53 and resistance could be overcome by c-FLIP(L) downmodulation. Here, we studied the association between c-FLIP(L) and p53 expressions and their prognostic impact in EOC patients. Tumor tissue from 207 patients diagnosed with primary EOC was analyzed by immunohistochemistry (IHC) for c-FLIP(L) and p53 expressions, and multiple correspondence analysis (MCA) was used to evaluate the multivariable pattern of association among patients' clinical-pathological characteristics and biological determinants. IHC revealed c-FLIP(L) expression and p53 nuclear accumulation inversely related (P = 0.0001; odds ratio = 0.29, confidence interval (CI) = 0.15-0.055). MCA indicated that p53 accumulation was associated to clinical-pathological variables, while c-FLIP(L) expression contributed to the overall association pattern independently from other's clinical characteristics and complementary to p53. Kaplan-Meier curves showed a reduced survival time according to c-FLIP(L) expression in concert with p53 accumulation (median overall survival (OS): 35 months) compared with lack of expression of both markers (median OS: 110 months; log-rank test, P value = 0.024). The multivariable Cox regression model, adjusted for known prognostic factors, identified c-FLIP(L) expression, but not p53 nuclear accumulation, as an independent prognostic factor for adverse outcome (hazard ratio = 1.82, 95% CI = 1.17-2.82; P = 0.008). Altogether these data support the independent contribution of c-FLIP(L) in refining the prognostic information obtained from standard clinical-pathological indicators, confirming its pivotal role in promoting cell survival.

Subcellular localization of activated leukocyte cell adhesion molecule is a molecular predictor of survival in ovarian carcinoma patients.

PURPOSE: Currently available clinicopathologic prognostic factors are imperfect predictors of clinical course in advanced-stage epithelial ovarian cancer patients. New molecular predictors are needed to identify patients with higher risk of relapse or death from disease. In a retrospective study, we investigated the prognostic impact of activated leukocyte cell adhesion molecule (ALCAM) expression in epithelial ovarian cancer. EXPERIMENTAL DESIGN: We analyzed the effect of cell-anchorage loss on ALCAM cellular localization in vitro and assessed ALCAM expression by immunohistochemistry in a series of 109 well-characterized epithelial ovarian cancer patient samples. Chi-square test, Kaplan-Meier method, and Cox proportional hazard analyses were used to relate ALCAM cellular localization to clinical-pathologic parameters and to overall survival (OS) rate. RESULTS: Loss of epithelial ovarian cancer cell anchorage was associated both in vitro and in vivo with decreased ALCAM membrane expression. In vivo, ALCAM was localized to cell membrane in normal surface ovarian epithelium, whereas in 67% of the epithelial ovarian cancer samples, membrane localization was decreased or even lost, and the molecule was mainly expressed in cytoplasm. Median OS in this group of patients was 58 months, whereas a median OS was not yet reached in patients with ALCAM membrane localization (P = 0.036, hazard ratio [HR] = 2.0, 95% confidence interval [CI] 1.1 to 3.5). In a multivariate Cox regression model including all the available clinicopathologic variables, loss of ALCAM membrane expression was an independent factor of unfavorable prognosis (P = 0.042, HR = 2.15, 95% CI: 1.0 to 4.5). CONCLUSIONS: Decreased/lost ALCAM membrane expression is a marker of poorer outcome in epithelial ovarian cancer patients and might help to identify patients who could benefit from more frequent follow-up or alternative therapeutic modalities.

Focal Recurrent Copy Number Alterations Characterize Disease Relapse in High Grade Serous Ovarian Cancer Patients with Good Clinical Prognosis: A Pilot Study.

High grade serous ovarian cancer (HGSOC) retains high molecular heterogeneity and genomic instability, which currently limit the treatment opportunities. HGSOC patients receiving complete cytoreduction (R0) at primary surgery and platinum-based therapy may unevenly experience early disease relapse, in spite of their clinically favorable prognosis. To identify distinctive traits of the genomic landscape guiding tumor progression, we focused on the R0 patients of The Cancer Genome Atlas (TCGA) ovarian serous cystadenocarcinoma (TCGA-OV) dataset and classified them according to their time to relapse (TTR) from surgery. We included in the study two groups of R0-TCGA patients experiencing substantially different outcome: Resistant (R; TTR ≤ 12 months; n = 11) and frankly Sensitive (fS; TTR ≥ 24 months; n = 16). We performed an integrated clinical, RNA-Sequencing, exome and somatic copy number alteration (sCNA) data analysis. No significant differences in mutational landscape were detected, although the lack of BRCA-related mutational signature characterized the R group. Focal sCNA analysis showed a higher frequency of amplification in R group and deletions in fS group respectively, involving cytobands not commonly detected by recurrent sCNA analysis. Functional analysis of focal sCNA with a concordantly altered gene expression identified in R group a gain in Notch, and interferon signaling and fatty acid metabolism. We are aware of the constraints related to the low number of OC cases analyzed. It is worth noting, however, that the sCNA identified in this exploratory analysis and characterizing Pt-resistance are novel, deserving validation in a wider cohort of patients achieving complete surgical debulking.