Gene expression signatures differentiate ovarian/peritoneal serous carcinoma from diffuse malignant peritoneal mesothelioma

miR-205 Regulates Tamoxifen Resistance by Targeting Estrogen Receptor Coactivator MED1 in Human Breast Cancer

Background/Objectives: Estrogen receptor-α coactivator MED1 is overexpressed in 40-60% of human breast cancers, and its high expression correlates with poor disease-free survival of patients undergoing anti-estrogen therapy. However, the molecular mechanism underlying MED1 upregulation and activation in breast cancer treatment resistance remains elusive. Methods: miRNA and mRNA expression analysis was performed using the NCBI GEO database. MED1 targeting and its impact on therapy resistance was evaluated in control and tamoxifen-resistant breast cancer cell lines by miR-205 overexpression and inhibition. Immunoblotting, chromatin immunoprecipitation, and luciferase reporter assays were used to understand the molecular mechanism of MED1-mediated tamoxifen resistance. Mice xenograft models were used to validate treatment efficacy and molecular mechanisms in vivo. Results: miR-205 was found to directly target and suppress the expression of MED1 through bioinformatic analyses and experimental validations. An inverse correlation of miR-205 and MED1 was observed in breast cancer patients with high MED1/low miR-205, indicative of poor prognosis in long-term anti-estrogen treatment. Furthermore, the depletion of miR-205 was observed in tamoxifen-resistant breast cancer cells overexpressing MED1. The restoration of miR-205 expression attenuated MED1 expression and re-sensitized cells to tamoxifen both in vitro and in vivo. Interestingly, miR205 was also found to target another key regulatory gene, HER3, which drives PI3K/Akt signaling and MED1 activation by phosphorylation. Importantly, we found ER target gene transcription and promoter cofactor recruitment by tamoxifen can be reversed by induced miR205 expression. Conclusions: Altogether, miR-205 functions as a negative regulator of MED1 and HER3, affecting the regulation of the HER3-PI3K/Akt-MED1 axis in anti-estrogen resistance, and could serve as a potential therapeutic regime to overcome treatment resistance.

Malignant peritoneal mesothelioma interactome with 417 novel protein-protein interactions

BACKGROUND

Malignant peritoneal mesothelioma (MPeM) is an aggressive cancer affecting the abdominal peritoneal lining and intra-abdominal organs, with a median survival of ~2.5 years.

METHODS

We constructed the protein interactome of 59 MPeM-associated genes with previously known protein-protein interactions (PPIs) as well as novel PPIs predicted using our previously developed HiPPIP computational model and analysed it for transcriptomic and functional associations and for repurposable drugs.

RESULTS

The MPeM interactome had over 400 computationally predicted PPIs and 4700 known PPIs. Transcriptomic evidence validated 75.6% of the genes in the interactome and 65% of the novel interactors. Some genes had tissue-specific expression in extramedullary hematopoietic sites and the expression of some genes could be correlated with unfavourable prognoses in various cancers. 39 out of 152 drugs that target the proteins in the interactome were identified as potentially repurposable for MPeM, with 29 having evidence from prior clinical trials, animal models or cell lines for effectiveness against peritoneal and pleural mesothelioma and primary peritoneal cancer. Functional modules related to chromosomal segregation, transcriptional dysregulation, IL-6 production and hematopoiesis were identified from the interactome. The MPeM interactome overlapped significantly with the malignant pleural mesothelioma interactome, revealing shared molecular pathways.

CONCLUSIONS

Our findings demonstrate the utility of the interactome in uncovering biological associations and in generating clinically translatable results.

Claudin-10 is a new candidate prognostic marker in metastatic high-grade serous carcinoma

The objective of this study was to analyze the expression and prognostic role of the tight junction protein claudin-10 in high-grade serous carcinoma (HGSC). Claudin-10 protein expression by immunohistochemistry was analyzed in 588 HGSC (414 effusions, 174 surgical specimens). Expression in mesotheliomas (n = 97; 47 effusions, 50 surgical specimens) was studied for comparative purposes. CLDN10 mRNA expression by quantitative RT-PCR (qRT-PCR) was analyzed in 40 HGSC effusions. Claudin-10 protein expression was found in 360/588 (61%) HGSC vs. 19/97 (20%) mesotheliomas (p < 0.001), and was higher in HGSC surgical specimens compared to effusions (p < 0.001). qRT-PCR confirmed the presence of CLDN10 mRNA in HGSC effusions. High (> 25%) claudin-10 expression in HGSC effusions was significantly associated with shorter overall survival (OS; p = 0.036) and progression-free survival (PFS; p = 0.045) in univariate analysis, and was an independent prognosticator of OS in multivariate analysis (p = 0.045). In conclusion, claudin-10 protein expression is higher in HGSC compared to mesothelioma, although the diagnostic power of this marker appear to be lesser than other claudin family members. Claudin-10 expression in HGSC effusions is marker of more aggressive disease.

High RAS-related protein Rab-7a (RAB7A) expression is a poor prognostic factor in pancreatic adenocarcinoma

Pancreatic adenocarcinoma (PAAD) is a frequent type of cancer in adults worldwide, and the search for better biomarkers is one of the current challenges. Although RAB7A is associated with tumour progression in multiple tumour types, there are only a few reports in PAAD. Therefore, in this paper, RNA sequencing data were obtained from TCGA(The Cancer Genome Atlas) and GTEx to analyse RAB7A expression and differentially expressed genes (DEGs) in PAAD. The functional enrichment of RAB7A-associated DEGs was analysed by protein‒protein interaction (PPI) networks, immune cell infiltration analysis and GO/KEGG analyses. Additionally, Kaplan‒Meier and Cox regression analyses were used to determine the clinical significance of RAB7A in PAAD. High RAB7A expression was associated with poor prognosis in 182 PAAD specimens, including subgroups of patients aged ≤ 65 years, with male sex, not receiving radiotherapy, and with a history of previous alcohol consumption (P < 0.05). Cox regression analysis showed that elevated RAB7A was an independent prognostic factor, and the prognostic nomogram model included radiotherapy status, presence of postoperative tumour residual and histologic grade. Overall, RAB7A overexpression may serve as a biomarker for poor outcome in pancreatic cancer. The DEGs and pathways revealed in this work provide a tentative molecular mechanism for the pathogenesis and progression of PAAD.

Linking Late Endosomal Cholesterol with Cancer Progression and Anticancer Drug Resistance

Cancer cells undergo drastic metabolic adaptions to cover increased bioenergetic needs, contributing to resistance to therapies. This includes a higher demand for cholesterol, which often coincides with elevated cholesterol uptake from low-density lipoproteins (LDL) and overexpression of the LDL receptor in many cancers. This implies the need for cancer cells to accommodate an increased delivery of LDL along the endocytic pathway to late endosomes/lysosomes (LE/Lys), providing a rapid and effective distribution of LDL-derived cholesterol from LE/Lys to other organelles for cholesterol to foster cancer growth and spread. LDL-cholesterol exported from LE/Lys is facilitated by Niemann–Pick Type C1/2 (NPC1/2) proteins, members of the steroidogenic acute regulatory-related lipid transfer domain (StARD) and oxysterol-binding protein (OSBP) families. In addition, lysosomal membrane proteins, small Rab GTPases as well as scaffolding proteins, including annexin A6 (AnxA6), contribute to regulating cholesterol egress from LE/Lys. Here, we summarize current knowledge that links upregulated activity and expression of cholesterol transporters and related proteins in LE/Lys with cancer growth, progression and treatment outcomes. Several mechanisms on how cellular distribution of LDL-derived cholesterol from LE/Lys influences cancer cell behavior are reviewed, some of those providing opportunities for treatment strategies to reduce cancer progression and anticancer drug resistance.

Potential roles of claudin-3 and claudin-4 in ovarian cancer management

BACKGROUND

Ovarian cancer has the highest mortality amongst all gynaecological malignancies, with around two-thirds of patients diagnosed with advanced disease due to late presentation. Furthermore, around 90% of patients develop recurrence and eventually become chemoresistant. Therefore, there is a high demand to identify biomarkers specific to this disease for screening for early detection, as well as new therapeutic targets. Tight junctions (TJs) regulate paracellular permeability and are vital in establishing epithelial cell polarity. One hallmark of tumorigenesis is the loss of TJs, with loss of cell-to-cell adhesion. Claudins are integral TJ membrane proteins, which have been found to play a critical role in maintaining the TJ's barrier function. Furthermore, claudin-3 (CLDN3) and claudin-4 (CLDN4) are overexpressed in ovarian cancer. This article aims to explore the biological role of CLDN3 and CLDN4 and their potential in different aspects of the management of ovarian cancer.

MAIN BODY

CLDN3 and CLDN4 have been shown to be effective markers for the early detection of ovarian cancer. Whilst there is difficulty in screening for both claudins in serum, their assessment by gene expression analysis and immunohistochemical methods shows promising potential as diagnostic and prognostic biomarkers for ovarian cancer. The localisation and overexpression of claudins, such as CLDN3, have been shown to correlate with poorer survival outcomes. The added value of combining claudins with other markers such as CA125 for diagnosis has also been highlighted. Therapeutically, CLDN3 and more so CLDN4 have been shown to be effective targets of Clostridium perfringens enterotoxin (CPE). Interestingly, CPE has also been shown to resensitise chemoresistant tumours to therapy.

CONCLUSIONS

This review presents the diagnostic and prognostic potential of CLDN3 and CLDN4 and their emerging role as therapeutic targets in ovarian cancer. Clinical trials are required to validate the promising results of the in vitro and in vivo studies for CLDN3 and CLDN4, possibly adding onto current ovarian cancer management.

Identification of Novel Diagnostic Markers for Malignant Pleural Mesothelioma Using a Reverse Translational Approach Based on a Rare Synchronous Tumor

Although the routine use of immunohistochemistry has improved the accuracy of histopathologic diagnosis in clinical practice, new methods for discovering novel diagnostic markers are still needed. We sought new diagnostic markers for malignant pleural mesothelioma (MPM) using a reverse translational approach with limited archival tissues from a very rare case. Total RNA extracted from formalin-fixed paraffin-embedded (FFPE) tissues of a synchronous collision tumor consisting of MPM and pulmonary adenocarcinoma (PAC) was employed for gene expression profiling (GEP) analysis. Among the 54 genes selected by GEP analysis, we finally identified the following two candidate MPM marker genes: PHGDH and TRIM29. Immunohistochemical analysis of 48 MM and 20 PAC cases showed that both PHGDH and TRIM29 had sensitivity and specificity almost equivalent to those of calretinin (sensitivity 50% and 46% vs. 63%, and specificity 95% and 100% vs. 100%, respectively). Importantly, of the 23 epithelioid MMs, all 3 calretinin-negative cases were positive for TRIM29. These two markers may be diagnostically useful for immunohistochemical distinction between MPMs and PACs. This successful reverse translational approach based on FFPE samples from one very rare case encourages the further use of such samples for the development of novel diagnostic markers.

Adaptation of the Golgi Apparatus in Cancer Cell Invasion and Metastasis

The Golgi apparatus plays a central role in normal cell physiology by promoting cell survival, facilitating proliferation, and enabling cell-cell communication and migration. These roles are partially mediated by well-known Golgi functions, including post-translational modifications, lipid biosynthesis, intracellular trafficking, and protein secretion. In addition, accumulating evidence indicates that the Golgi plays a critical role in sensing and integrating external and internal cues to promote cellular homeostasis. Indeed, the unique structure of the mammalian Golgi can be fine-tuned to adapt different Golgi functions to specific cellular needs. This is particularly relevant in the context of cancer, where unrestrained proliferation and aberrant survival and migration increase the demands in Golgi functions, as well as the need for Golgi-dependent sensing and adaptation to intrinsic and extrinsic stressors. Here, we review and discuss current understanding of how the structure and function of the Golgi apparatus is influenced by oncogenic transformation, and how this adaptation may facilitate cancer cell invasion and metastasis.

Tumor-Derived Extracellular Vesicles and the Immune System-Lessons From Immune-Competent Mouse-Tumor Models

Tumor-derived extracellular vesicles (TEVs) are important regulators of the immune response in cancer; however, most research so far has been carried out using cell culture systems. Immune-competent murine tumor models currently provide the best platform to assess proposed roles of TEVs using in vivo animal models and therefore are important for examining interactions between TEVs and the immune system. In this review, we present the current knowledge on TEVs using in vivo tumor-bearing animal models, with a focus on the role of TEVs in mediating crosstalk between tumor cells and both adaptive and innate immune cells. In particular, we address the question how animal models can clarify the reported heterogeneity of TEV effects in both anti-tumor responses and evasion of immune surveillance. The potential of TEVs in mediating direct antigen-presenting functions supports their potential as cancer vaccine therapeutics, therefore, we provide an overview of key findings of TEV trials that have the potential as novel immunotherapies, and shed light on challenges in the path toward the first in-human trials. We also highlight the important updates on the methods that continue to enhance the rigor and reproducibility of EV studies, particularly in functional animal models.

Rab7 Is Associated with Poor Prognosis of Gastric Cancer and Promotes Proliferation, Invasion, and Migration of Gastric Cancer Cells

BACKGROUND Rab7 belongs to the Ras oncogene family. Many studies have shown that its dysfunction is associated with many types of malignant tumors, but its effect on the pathogenesis of gastric cancer (GC) is still unknown. Therefore, we investigated the effect and mechanism of Rab7 in GC. MATERIAL AND METHODS The expression of Rab7 in GC and adjacent tissues was detected by immunohistochemistry, Western blot analysis, and qRT-PCR. The relationship of Rab7 with clinicopathological parameters and prognosis was analyzed. The expressions of Rab7, PI3K, and AKT in GC cells were assessed by Western blot. Overexpressed and silenced GC cell lines were constructed and AGS cells were treated with LY294002. The proliferation capacity of GC cells was detected by CCK8 assay, cell cycle changes were detected by flow cytometry, and the invasion and migration abilities of GC cells were assessed by transwell assay. RESULTS The expression of Rab7 was upregulated in the samples and cells, and was positively correlated with lymph node metastasis but negatively correlated with histological differentiation and clinical prognosis. In cell function experiments, overexpression of Rab7 induced the transition from S phase to G2 phase and promoted the proliferation, invasion, and migration of GC cells. Our assessment of the molecular mechanism showed that Rab7 promoted the phosphorylation of PI3K and AKT in GC cells. Incubation with the PI3K inhibitor Ly294002 impaired the enhanced effect of Rab7 overexpression on proliferation, migration, and invasion abilities of GC cells. These results show that the Rab7 affects GC cell progression by modulating the PI3K/AKT pathway. CONCLUSIONS Rab7 could be a prognostic biomarker and therapeutic target of the PI3K/AKT pathway in GC.

Loss of Tenascin-X expression during tumor progression: A new pan-cancer marker

Cancer is a systemic disease involving multiple components produced from both tumor cells themselves and surrounding stromal cells. The pro- or anti-tumoral role of the stroma is still under debate. Indeed, it has long been considered the main physical barrier to the diffusion of chemotherapy by its dense and fibrous nature and its poor vascularization. However, in murine models, the depletion of fibroblasts, the main ExtraCellular Matrix (ECM)-producing cells, led to more aggressive tumors even though they were more susceptible to anti-angiogenic and immuno-modulators. Tenascin-C (TNC) is a multifunctional matricellular glycoprotein (i.e. an ECM protein also able to induce signaling pathway) and is considered as a marker of tumor expansion and metastasis. However, the status of other tenascin (TN) family members and particularly Tenascin-X (TNX) has been far less studied during this pathological process and is still controversial. Herein, through (1) in silico analyses of the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases and (2) immunohistochemistry staining of Tissue MicroArrays (TMA), we performed a large and extensive study of TNX expression at both mRNA and protein levels (1) in the 6 cancers with the highest incidence and mortality in the world (i.e. lung, breast, colorectal, prostate, stomach and liver) and (2) in the cancers for which sparse data regarding TNX expression already exist in the literature. We thus demonstrated that, in most cancers, TNX expression is significantly downregulated during cancer progression and we also highlighted, when data were available, that high TNXB mRNA expression in cancer is correlated with a good survival prognosis.

MiR-205 Dysregulations in Breast Cancer: The Complexity and Opportunities

MicroRNAs (miRNAs) are endogenous non-coding small RNAs that downregulate target gene expression by imperfect base-pairing with the 3' untranslated regions (3'UTRs) of target gene mRNAs. MiRNAs play important roles in regulating cancer cell proliferation, stemness maintenance, tumorigenesis, cancer metastasis, and cancer therapeutic resistance. While studies have shown that dysregulation of miRNA-205-5p (miR-205) expression is controversial in different types of human cancers, it is generally observed that miR-205-5p expression level is downregulated in breast cancer and that miR-205-5p exhibits a tumor suppressive function in breast cancer. This review focuses on the role of miR-205-5p dysregulation in different subtypes of breast cancer, with discussions on the effects of miR-205-5p on breast cancer cell proliferation, epithelial-mesenchymal transition (EMT), metastasis, stemness and therapy-resistance, as well as genetic and epigenetic mechanisms that regulate miR-205-5p expression in breast cancer. In addition, the potential diagnostic and therapeutic value of miR-205-5p in breast cancer is also discussed. A comprehensive list of validated miR-205-5p direct targets is presented. It is concluded that miR-205-5p is an important tumor suppressive miRNA capable of inhibiting the growth and metastasis of human breast cancer, especially triple negative breast cancer. MiR-205-5p might be both a potential diagnostic biomarker and a therapeutic target for metastatic breast cancer.

Serum calretinin as an independent predictor for platinum resistance and prognosis in ovarian cancer

Calretinin (CRT) is a calcium-binding protein that controls intracellular calcium signaling. Besides its prominent expression in neurons, serum CRT (sCRT) has recently been suggested as blood-based biomarker for prediagnostic mesothelioma detection. CRT is expressed in ovarian cancer tissues in up to 40% of cases; however, its clinical relevance as blood-based biomarker for ovarian cancer is unknown. sCRT was determined by calretinin enzyme-linked immunoabsorbent assay (Calretinin-ELISA, DLD Diagnostika GmbH, Hamburg, Germany) in a total of 515 serum samples from 116 healthy controls and 134 ovarian cancer patients (thereof 86% with Fédération Internationale de Gynécologie et d'Obstétrique [FIGO] III/IV), including samples at primary diagnosis and at four longitudinal follow-up time points in the course of treatment and at recurrence. sCRT level was significantly increased in ovarian cancer patients compared to healthy controls (estimated difference = 0.3 ng/ml, p < 0.001), was mostly independent from CA125 (r ≤ 0.388) and enabled accurate discrimination between cases and controls (area under the curve = 0.85). Higher sCRT level at primary diagnosis predicted suboptimal debulking (p < 0.001) and was associated with advanced FIGO-stage (p < 0.001) and increased amount of ascites (p < 0.001). sCRT levels at primary diagnosis and its dynamics in the course of chemotherapy were independent predictors for poor progression-free survival (hazard ratio [HR] = 1.99, confidence interval [CI] = [1.13-3.52], p = 0.0181) and overall survival (HR = 15.4, CI = [1.92-124], p = 0.0099). Furthermore, sCRT at primary diagnosis or a relative sCRT increase in the time interval between surgery and the onset of chemotherapy were both independent predictors of platinum resistance (OR = 4.99, CI = [3.50-16,001], p = 0.0016; OR = 2.41, CI = [1.37-6,026], p = 0.0271, respectively). This is the first study that suggests sCRT as liquid biopsy marker for independent prediction of platinum resistance and prognosis.

Role of the RAB7 Protein in Tumor Progression and Cisplatin Chemoresistance

RAB7 is a small guanosine triphosphatase (GTPase) extensively studied as regulator of vesicular trafficking. Indeed, its role is fundamental in several steps of the late endocytic pathway, including endosome maturation, transport from early endosomes to late endosomes and lysosomes, clustering and fusion of late endosomes and lysosomes in the perinuclear region and lysosomal biogenesis. Besides endocytosis, RAB7 is important for a number of other cellular processes among which, autophagy, apoptosis, signaling, and cell migration. Given the importance of RAB7 in these cellular processes, the interest to study the role of RAB7 in cancer progression is widely grown. Here, we describe the current understanding of oncogenic and oncosuppressor functions of RAB7 analyzing cellular context and other environmental factors in which it elicits pro and/or antitumorigenic effects. We also discuss the role of RAB7 in cisplatin resistance associated with its ability to regulate the late endosomal pathway, lysosomal biogenesis and extracellular vesicle secretion. Finally, we examined the potential cancer therapeutic strategies targeting the different molecular events in which RAB7 is involved.

Aberrant expression of genes associated with stemness and cancer in endometria and endometrioma in a subset of women with endometriosis

STUDY QUESTION

Is there molecular evidence for a link between endometriosis and endometriosis-associated ovarian cancers (EAOC)?

STUDY ANSWER

We identified aberrant gene expression signatures associated with malignant transformation in a small subgroup of women with ovarian endometriosis.

WHAT IS KNOWN ALREADY

Epidemiological studies have shown an increased risk of EAOC in women with ovarian endometriosis. However, the cellular and molecular changes leading to EAOC are largely unexplored.

STUDY DESIGN, SIZE, DURATION

CD73+CD90+CD105+ multipotent stem cells/progenitors (SC cohort) were isolated from endometrium (n = 18) and endometrioma (n = 11) of endometriosis patients as well as from the endometrium of healthy women (n = 14). Extensive phenotypic and functional analyses were performed in vitro on expanded multipotent stem cells/progenitors to confirm their altered characteristics. Aberrant gene signatures were also validated in paired-endometrium and -endometrioma tissue samples from another cohort (Tissue cohort, n = 19) of endometriosis patients.

PARTICIPANTS/MATERIALS, SETTINGS, METHODS

Paired-endometrial and -endometriotic biopsies were obtained from women with endometriosis (ASRM stage III-IV) undergoing laparoscopic surgery. Control endometria were obtained from healthy volunteers. Isolated CD73+CD90+CD105+ SC were evaluated for the presence of known endometrial surface markers, colony forming efficiency, multi-lineage differentiation, cell cycle distribution and 3D-spheroid formation capacity. Targeted RT-PCR arrays, along with hierarchical and multivariate clustering tools, were used to determine both intergroup and intragroup gene expression variability for stem cell and cancer-associated markers, in both SC+ and tissue cohorts.

MAIN RESULTS AND THE ROLE OF CHANCE

Isolated and expanded SC+ from both control and patient groups showed significantly higher surface expression of W5C5+, clonal expansion and 3D-spheroid formation capacity (P < 0.05) compared with SC-. The SC+ cells also undergo mesenchymal lineage differentiation, unlike SC-. Gene expression from paired-endometriosis samples showed significant downregulation of PTEN, ARID1A and TNFα (P < 0.05) in endometrioma compared with paired-endometrium SC+ samples. Hierarchical and multivariate clustering from both SC+ and tissue cohorts together identified 4 out of 30 endometrioma samples with aberrant expression of stem cell and cancer-associated genes, such as KIT, HIF2α and E-cadherin, altered expression ratio of ER-β/ER-α and downregulation of tumour suppressor genes (PTEN and ARID1A). Thus, we speculate that above changes may be potentially relevant to the development of EAOC.

LARGE-SCALE DATA

N/A.

LIMITATIONS, REASON FOR CAUTION

As the reported frequency of EAOC is very low, we did not have access to those samples in our study. Moreover, by adopting a targeted gene array approach, we might have missed several other potentially-relevant genes associated with EAOC pathogenesis. The above panel of markers should be further validated in archived tissue samples from women with endometriosis who later in life developed EAOC.

WIDER IMPLICATIONS OF THE FINDINGS

Knowledge gained from this study, with further confirmation on EAOC cases, may help in developing screening methods to identify women with increased risk of EAOC.

STUDY FUNDING/COMPETING INTEREST(S)

The study is funded by the Swedish Research Council (2012-2844), a joint grant from Stockholm County and Karolinska Institutet (ALF), RGD network at Karolinska Institutet, Karolinska Institutet for doctoral education (KID), Estonian Ministry of Education and Research (IUT34-16), Enterprise Estonia (EU48695), Horizon 2020 innovation program (WIDENLIFE, 692065), European Union's FP7 Marie Curie Industry-Academia Partnerships and Pathways funding (IAPP, SARM, EU324509) and MSCA-RISE-2015 project MOMENDO (691058). All authors have no competing interest.

Bilateral salpingectomy to reduce the risk of ovarian/fallopian/peritoneal cancer in women at average risk: a position statement of the Korean Society of Obstetrics and Gynecology (KSOG)

Based on the current understanding of a preventive effect of bilateral salpingectomy on ovarian/fallopian/peritoneal cancers, the Korean Society of Obstetrics and Gynecology, Korean Society of Gynecologic Endocrinology, Korean Society of Gynecologic Oncology, Korean Society of Maternal Fetal Medicine, and Korean Society for Reproductive Medicine support the following recommendations: • Women scheduled for hysterectomy for benign gynecologic disease should be informed that bilateral salpingectomy reduces the risk of ovarian/fallopian/peritoneal cancer, and they should be counseled regarding this procedure at the time of hysterectomy. • Although salpingectomy is generally considered as a safe procedure in terms of preserving ovarian reserve, there is a lack of evidences representing its long-term outcomes. Therefore, patients should be informed about the minimal potential of this procedure for decreasing ovarian reserve. • Prophylactic salpingectomy during vaginal hysterectomy is favorable in terms of prevention of ovarian/fallopian/peritoneal cancer, although operation-related complications minimally increase with this procedure, compared to the complications associated with vaginal hysterectomy alone. Conversion to open or laparoscopic approach from vaginal approach to perform prophylactic salpingectomy is not recommended. • Women who desire permanent sterilization at the time of cesarean delivery could be counseled for prophylactic salpingectomy before surgery on an individual basis.

Disruption of endocytic trafficking protein Rab7 impairs invasiveness of cholangiocarcinoma cells

BACKGROUND

Alterations and mutations of endo-lysosomal trafficking proteins have been associated with cancer progression. Identification and characterization of endo-lysosomal trafficking proteins in invasive cholangiocarcinoma (CCA) cells may benefit prognosis and drug design for CCA.

OBJECTIVE

To identify and characterize endo-lysosomal trafficking proteins in invasive CCA.

METHODS

A lysosomal-enriched fraction was isolated from a TNF-α induced invasive CCA cell line (KKU-100) and uninduced control cells and protein identification was performed with nano-LC MS/MS. Novel lysosomal proteins that were upregulated in invasive CCA cells were validated by real-time RT-PCR. We selected Rab7 for further studies of protein level using western blotting and subcellular localization using immunofluorescence. The role of Rab7 in CCA invasion was determined by siRNA gene knockdown and matrigel transwell assay.

RESULTS

Rab7 mRNA and protein were upregulated in invasive CCA cells compared with non-treated controls. Immunofluorescence studies demonstrated that Rab7 was expressed predominantly in invasive CCA cells and was localized in the cytoplasm and lysosomes. Suppression of Rab7 translation significantly inhibited TNF-α-induced cell invasion compared to non-treated control (p= 0.044).

CONCLUSIONS

Overexpression of Rab7 in CCA cells was associated with cell invasion, supporting Rab7 as a novel candidate for the development of diagnostic and therapeutic strategies for CCA.

The role of the oncogenic Rab35 in cancer invasion, metastasis, and immune evasion, especially in leukemia

The study of cancer has allowed researchers to describe some biological characteristics that tumor cells acquire during their development, known as the “hallmarks of cancer” but more research is needed to expand our knowledge about cancer biology and to generate new strategies of treatment. The role that RabGTPases might play in some hallmarks of cancer represents interesting areas of study since these proteins are frequently altered in cancer. However, their participation is not well known. Recently, Rab35was recognized as an oncogenic RabGTPase and and because of its association with different cellular functions, distinctly important in immune cells, a possible role of Rab35 in leukemia can be suggested. Nevertheless, the involvement of Rab35 in cancer remains poorly understood and its possible specific role in leukemia remains unknown. In this review, we analyze general aspects of the participation of RabGTPases in cancer, and especially, the plausible role of Rab35 in leukemia.

Endosomal sorting and c-Cbl targeting of paxillin to autophagosomes regulate cell-matrix adhesion turnover in human breast cancer cells

Post-translational mechanisms regulating cell-matrix adhesion turnover during cell locomotion are not fully elucidated. In this study, we uncovered an essential role of Y118 site-specific tyrosine phosphorylation of paxillin, an adapter protein of focal adhesion complexes, in paxillin recruitment to autophagosomes to trigger turnover of peripheral focal adhesions in human breast cancer cells. We demonstrate that the Rab-7 GTPase is a key upstream regulator of late endosomal sorting of tyrosine118-phosphorylated paxillin, which is subsequently recruited to autophagosomes via the cargo receptor c-Cbl. Essentially, this recruitment involves a direct and selective interaction between Y118-phospho-paxillin, c-Cbl, and LC3 and is independent from c-Cbl E3 ubiquitin ligase activity. Interference with the Rab7-paxillin-autophagy regulatory network using genetic and pharmacological approaches greatly impacted focal adhesion stability, cell locomotion and progression to metastasis using a panel of human breast cancer cells. Together, these results provide novel insights into the requirement of phospho-site specific post-translational mechanism of paxillin for autophagy targeting to regulate cell-matrix adhesion turnover and cell locomotion in breast cancer cells.

Transcriptomic Analysis of the Claudin Interactome in Malignant Pleural Mesothelioma: Evaluation of the Effect of Disease Phenotype, Asbestos Exposure, and CDKN2A Deletion Status

Malignant pleural mesothelioma (MPM) is a highly aggressive tumor primarily associated with asbestos exposure. Early detection of MPM is restricted by the long latency period until clinical presentation, the ineffectiveness of imaging techniques in early stage detection and the lack of non-invasive biomarkers with high sensitivity and specificity. In this study we used transcriptome data mining in order to determine which CLAUDIN (CLDN) genes are differentially expressed in MPM as compared to controls. Using the same approach we identified the interactome of the differentially expressed CLDN genes and assessed their expression profile. Subsequently, we evaluated the effect of tumor histology, asbestos exposure, CDKN2A deletion status, and gender on the gene expression level of the claudin interactome. We found that 5 out of 15 studied CLDNs (4, 5, 8, 10, 15) and 4 out of 27 available interactors (S100B, SHBG, CDH5, CXCL8) were differentially expressed in MPM specimens vs. healthy tissues. The genes encoding the CLDN-15 and S100B proteins present differences in their expression profile between the three histological subtypes of MPM. Moreover, CLDN-15 is significantly under-expressed in the cohort of patients with previous history of asbestos exposure. CLDN-15 was also found significantly underexpressed in patients lacking the CDKN2A gene. These results warrant the detailed in vitro investigation of the role of CDLN-15 in the pathobiology of MPM.

Roles of the first-generation claudin binder, Clostridium perfringens enterotoxin, in the diagnosis and claudin-targeted treatment of epithelium-derived cancers

Given that most malignant tumors are derived from epithelium, developing a strategy for treatment of epithelium-derived cancers (i.e., carcinomas) is a pivotal issue in cancer therapy. Carcinomas, including ovarian, breast, prostate, and pancreatic cancers, are known to overexpress various claudins (CLDNs); in particular, CLDN-3 and -4 are frequently overexpressed in malignant case. The generation of CLDN binders is a key for expanding CLDN-targeted cancer therapy but has been delayed due to the small size of CLDN extracellular domains (approximately 50 amino acids for the first domain and 15 amino acids for the second) and their high homology among species. Interestingly, however, the receptors for Clostridium perfringens enterotoxin (CPE), a foodborne toxin in humans, happen to be identical to CLDN-3 and -4. Thus, the first CLDN binder, CPE, has provided us CLDN-targeted cancer therapy from a concept into a potential reality. In this review, we describe roles of CPE technology in cancer therapy and discuss future directions in the CLDN-targeting concept-to-therapy process.

CD24 is highly useful in differentiating high-grade serous carcinoma from benign and malignant mesothelial cells

CD24 was previously shown to be overexpressed in high-grade serous carcinoma (HGSC) effusions compared to malignant mesothelioma (MM) in gene expression array analysis. The present study validated this observation in a large series consisting of both effusions and surgical specimens. Effusions (n = 206; 100 HGSC, 16 ovarian carcinomas of other histological types, 54 breast carcinomas, 36 MM) and surgical specimens (n = 182; 117 ovarian carcinomas, 65 MM) were analyzed for CD24 expression using immunohistochemistry. CD24 was expressed in 105/116 (91%) ovarian carcinoma and 16/54 (30%) breast carcinoma effusions, while it was uniformly absent in MM (0/36; 0%; P < .001). Reactive mesothelial cells were CD24-negative in all carcinoma specimens. Comparative analysis of 117 solid primary (n = 43) and metastatic (n = 74) ovarian carcinomas and 65 solid MM specimens showed CD24 expression in 46% (54/117) of the former compared to 3% (2/65) of the latter (P < .001). Comparative analysis of ovarian carcinomas at different anatomic sites showed significantly higher CD24 expression in effusions compared to solid ovarian and metastatic lesions (P < .001), with similar results when analysis was limited to HGSC (P < .001). In conclusion, CD24 is a highly sensitive and specific marker of ovarian carcinoma in the differential diagnosis from MM and reactive mesothelium in effusions. CD24 is similarly a specific marker in surgical specimens, though with lower sensitivity. The overexpression of CD24 in ovarian carcinoma effusions compared to solid lesions may be due to the acquisition of cancer stem cell characteristics.

Malignant Nonhematological Effusion Characterization by Flow Cytometry

With the exception of hematological malignancies, flow cytometry (FC) is infrequently applied as an ancillary tool in the diagnosis of malignant effusions in most institutions. However, FC may be effectively used to differentiate between epithelial cells, mesothelial cells and leukocytes using antibodies against both cell surface and intracellular proteins, offering the advantage of quantitative analysis. Additionally, FC may be applied to the quantitative detection of cancer-associated molecules, including stem cell markers, as well as assessment of critical cellular processes, such as proliferation and apoptosis. Some of the latter tests may have relevance for monitoring treatment response in the presence of metastatic disease, although this does not constitute routine practice to date. This review summarizes current knowledge regarding the application of FC to serous effusions in the diagnostic setting, as well as in research into cancer biology focusing on clinical specimens. The studies published to date suggest a role for this method in the clinical setting in the context of diagnosis, prediction and prognosis.

Pre-analytical issues in effusion cytology

Effusions or body cavity fluids are amongst the most commonly submitted samples to the cytology laboratory. Knowledge of proper collection, storage, preservation and processing techniques is essential to ensure proper handling and successful analysis of the sample. This article describes how the effusions should be collected and proper conditions for submission. The different processing techniques to extract the cellular material and prepare slides satisfactory for microscopic evaluation are described such as direct smears, cytospins, liquid based preparations and cell blocks. The article further elaborates on handling the specimens for additional ancillary testing such as immunostaining and molecular tests, including predictive ones, as well as future research approaches.

RAB7 counteracts PI3K-driven macropinocytosis activated at early stages of melanoma development

Derailed endolysosomal trafficking is emerging as a widespread feature of aggressive neoplasms. However, the oncogenic signals that alter membrane homeostasis and their specific contribution to cancer progression remain unclear. Understanding the upstream drivers and downstream regulators of aberrant vesicular trafficking is distinctly important in melanoma. This disease is notorious for its inter- and intra-tumoral heterogeneity. Nevertheless, melanomas uniformly overexpress a cluster of endolysosomal genes, being particularly addicted to the membrane traffic regulator RAB7. Still, the underlying mechanisms and temporal determinants of this dependency have yet to be defined. Here we addressed these questions by combining electron microscopy, real time imaging and mechanistic analyses of vesicular trafficking in normal and malignant human melanocytic cells. This strategy revealed Class I PI3K as the key trigger of a hyperactive influx of macropinosomes that melanoma cells counteract via RAB7-mediated lysosomal degradation. In addition, gain- and loss-of-function in vitro studies followed by histopathological validation in clinical biopsies and genetically-engineered mouse models, traced back the requirement of RAB7 to the suppression of premature cellular senescence traits elicited in melanocytes by PI3K-inducing oncogenes. Together, these results provide new insight into the regulators and modes of action of RAB7, broadening the impact of endosomal fitness on melanoma development.

Onco-Golgi: Is Fragmentation a Gate to Cancer Progression?

The Golgi apparatus-complex is a highly dynamic organelle which is considered the "heart" of intracellular transportation. Since its discovery by Camillo Golgi in 1873, who described it as the "black reaction," and despite the enormous volume of publications about Golgi, this apparatus remains one of the most enigmatic of the cytoplasmic organelles. A typical mammalian Golgi consists of a parallel series of flattened, disk-shaped cisternae which align into stacks. The tremendous volume of Golgi-related incoming and outgoing traffic is mediated by different motor proteins, including members of the dynein, kinesin, and myosin families. Yet in spite of the strenuous work it performs, Golgi contrives to maintain its monolithic morphology and orchestration of matrix and residential proteins. However, in response to stress, alcohol, and treatment with many pharmacological drugs over time, Golgi undergoes a kind of disorganization which ranges from mild enlargement to critical scattering. While fragmentation of the Golgi was confirmed in cancer by electron microscopy almost fifty years ago, it is only in recent years that we have begun to understand the significance of Golgi fragmentation in the biology of tumors. Below author would like to focus on how Golgi fragmentation opens the doors for cascades of fatal pathways which may facilitate cancer progression and metastasis. Among the issues addressed will be the most important cancer-specific hallmarks of Golgi fragmentation, including aberrant glycosylation, abnormal expression of the Ras GTPases, dysregulation of kinases, and hyperactivity of myosin motor proteins.

MMP-7 is a highly specific negative marker for benign and malignant mesothelial cells in serous effusions

The aim of this study was to analyze the diagnostic role of MMP-7 in effusion cytology. Effusions (n = 356), consisting of 307 carcinomas (184 ovarian, 55 breast, 32 lung, 36 carcinomas of other origin) and 49 malignant mesotheliomas, were analyzed for MMP-7 expression using immunohistochemistry. MMP-7 was expressed in 124/307 (40%) carcinomas and was uniformly absent in malignant mesotheliomas (0/49; 0%; P < .001). Reactive mesothelial cells were similarly MMP-7 negative in all carcinoma specimens. In carcinomas, expression was most frequent in tumors of ovarian and other female genital (cervical and endometrial) origin (P < .001). The sensitivity and specificity of this marker in the differential diagnosis between high-grade serous carcinoma and malignant mesothelioma were 46% and 100%, respectively. In conclusion, MMP-7 expression is highly specific, though only of moderate sensitivity, for the diagnosis of carcinoma in the differential diagnosis from both benign and malignant mesothelial cells.

Claudin 3, 4, and 15 expression in solid tumors of lung adenocarcinoma versus malignant pleural mesothelioma

Epithelioid malignant pleural mesothelioma (MPM) can easily be confused with lung adenocarcinomas (ACAs). In serous effusion, claudin (cldn) 3 is shown to be useful in the diagnosis of mesothelioma vs ACAs. Cldn15 is reported to be overexpressed in epithelioid mesothelioma and absent in human airway epithelium. The aim was to assess the value of cldn3 and cldn4 compared to that of BerEp4 and thyroid transcription factor-1 (TTF1) in differentiating lung ACA from epithelioid MPM and to examine the expression of cldn15 in these tumors. The expression of cldn3, cldn4, cldn15, BerEp4, and TTF1 was examined by immunohistochemistry in a total of 62 human specimen including 28 epithelioid MPMs and 34 ACAs of the lung. In lung ACA, cldn4 was strongly expressed in all 34 (100%) specimens followed by cldn3 in 33 (97%) of 34. BerEp4 was expressed in 32 (94.1%) of 34. TTF1 reacted for only 20 (58.82%) of 34 cases of lung ACA. In MPM specimens, the expression of cldn3 and4 as well as that of TTF1 was completely absent. In contrast, BerEp4 was focally expressed in 5 (17.85%) of 28 cases of epithelioid MPM. Cldn15 was strongly expressed in 53% pf epithelioid MPMs but also in 50% of lung ACAs. Its expression was moderate in normal pleura and limited in normal lung. Cldn3 and cldn4 appear to be the best performing carcinoma markers in discriminating lung ACA from mesothelioma compared with BerEp4 and TTF1. There is no differential expression of cldn15 between the 2 pathologies. However, the limited cldn15 expression in normal tissues and high expression in tumors make it an attractive candidate for cancer therapy.

Expression status of candidate genes in mesothelioma tissues and cell lines

In order to broaden knowledge on the pathogenesis of malignant pleural mesothelioma (MPM), we reviewed studies on the MPM-transcriptome and identified 119 deregulated genes. However, there was poor consistency among the studies. Thus, the expression of these genes was further investigated in the present work using reverse transcriptase-quantitative PCR (RT-qPCR) in 15 MPM and 20 non-MPM tissue samples. Fifty-nine genes showed a statistically significant deregulation and were further evaluated in two epithelioid MPM cell lines (compared to MET-5A, a non-MPM cell line). Nine genes (ACSL1, CCNO, CFB, PDGFRB, SULF1, TACC1, THBS2, TIMP3, XPOT) were deregulated with statistical significance in both cell lines, 12 (ASS1, CCNB1, CDH11, COL1A1, CXADR, EIF4G1, GALNT7, ITGA4, KRT5, PTGIS, RAN, SOD1) in at least one cell line, whereas 7 (DSP, HEG1, MCM4, MSLN, NME2, NMU, TNPO2) were close but did not reach the statistical significance in any of the cell line. Patients whose MPM tissues expressed elevated mRNA levels of BIRC5, DSP, NME2, and THBS2 showed a statistically significant shorter overall survival. Although MPM is a poorly studied cancer, some features are starting to emerge. Novel cancer genes are suggested here, in particular those involved in cell-cell and cell-matrix interactions.

Diagnostic value of claudin-4 marker in pleural and peritoneal effusion cytology: Does it differentiate between metastatic adenocarcinoma and reactive mesothelial cells?

BACKGROUND

Several markers have been used to make a distinction between metastatic adenocarcinoma and reactive mesothelial cells in the body cavity effusions. This study aimed to evaluate the diagnostic value of claudin-4 marker in making such a distinction.

MATERIALS AND METHODS

In this cross-sectional study, a total of 92 pleural/peritoneol effusions have been studied, including 47 cases of definite metastatic carcinoma and 45 cases of reactive mesothelium, and definitely negative for malignancy. Specimens were collected from patients; cell block samples were derived and used for immunohistochemical staining. The antibody used for immunohistochemical labeling was monoclonal anti-claudin-4. In the evaluation, membrane-bound reactivity was considered as significant and positive cases were defined when at least more than 10% of tumor cells were distinctly labeled.

RESULTS

Claudin-4 protein was positive in 40 specimens of metastatic carcinoma, while none of the cases of reactive mesothelium stained with the marker. This was not detected in the mesothelial cells, though. Positive staining for claudin-4 was significantly more frequent in metastatic carcinoma than in the reactive mesothelium (P > 0.0001). The sensitivity and specificity of claudin-4 to distinguish reactive mesothelium from metastatic carcinoma were 85% (95% confidence interval [CI], 71.1-93.8%) and 100% (95% CI, 91.1-100%), respectively. Furthermore, negative likelihood ratio was 0.15 (95% CI, 0.08-0.29).

CONCLUSION

The results of this study demonstrated that claudin-4 is less frequently expressed in reactive mesothelium. Thus, this claudin may be helpful in differentiating metastatic carcinoma from reactive mesothelial cells in pleural and peritoneal fluid cytology specimen.

APOA1 mRNA expression in ovarian serous carcinoma effusions is a marker of longer survival

OBJECTIVES

We previously described the overexpression of APOA1 and GPX3 in ovarian/peritoneal serous carcinoma compared with breast carcinoma effusions using gene expression array analysis. The objective of the present study was to validate this finding and to analyze the association between these genes and clinicopathologic parameters, including survival, in advanced-stage ovarian serous carcinoma.

METHODS

APOA1 and GPX3 mRNA expression using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was analyzed in 121 effusions (101 ovarian, 20 breast carcinomas) and 85 solid ovarian carcinoma specimens (43 primary carcinomas, 42 metastases).

RESULTS

APOA1 and GPX3 transcript levels were significantly higher in ovarian carcinoma at all anatomic sites compared with breast carcinoma effusions (P < .001). GPX3 mRNA levels were significantly higher in primary carcinomas and solid metastases from patients who received neoadjuvant chemotherapy compared with chemo-naïve tumors (P = .016). APOA1 and GPX3 mRNA levels in the entire effusion series were unrelated to clinicopathologic parameters. However, higher APOA1 mRNA levels in primary diagnosis pre-chemotherapy effusions were significantly related to better overall survival (P = .045), a finding that retained its significance in Cox multivariate analysis (P = .016).

CONCLUSIONS

APOA1 and GPX3 mRNA levels on qRT-PCR effectively differentiate ovarian from breast carcinoma. APOA1 may be a novel prognostic marker in metastatic serous carcinoma.

Gene expression analysis in ovarian cancer - faults and hints from DNA microarray study

The introduction of microarray techniques to cancer research brought great expectations for finding biomarkers that would improve patients’ treatment; however, the results of such studies are poorly reproducible and critical analyses of these methods are rare. In this study, we examined global gene expression in 97 ovarian cancer samples. Also, validation of results by quantitative RT-PCR was performed on 30 additional ovarian cancer samples. We carried out a number of systematic analyses in relation to several defined clinicopathological features. The main goal of our study was to delineate the molecular background of ovarian cancer chemoresistance and find biomarkers suitable for prediction of patients’ prognosis. We found that histological tumor type was the major source of variability in genes expression, except for serous and undifferentiated tumors that showed nearly identical profiles. Analysis of clinical endpoints [tumor response to chemotherapy, overall survival, disease-free survival (DFS)] brought results that were not confirmed by validation either on the same group or on the independent group of patients. CLASP1 was the only gene that was found to be important for DFS in the independent group, whereas in the preceding experiments it showed associations with other clinical endpoints and with BRCA1 gene mutation; thus, it may be worthy of further testing. Our results confirm that histological tumor type may be a strong confounding factor and we conclude that gene expression studies of ovarian carcinomas should be performed on histologically homogeneous groups. Among the reasons of poor reproducibility of statistical results may be the fact that despite relatively large patients’ group, in some analyses one has to compare small and unequal classes of samples. In addition, arbitrarily performed division of samples into classes compared may not always reflect their true biological diversity. And finally, we think that clinical endpoints of the tumor probably depend on subtle changes in many and, possibly, alternative molecular pathways, and such changes may be difficult to demonstrate.

Supporting a role for the GTPase Rab7 in prostate cancer progression

Invasion and subsequent metastasis is the major cause of death from most cancers including prostate cancer. Herein we report on the potential tumor suppressive properties of Rab7, a GTPase that regulates trafficking of lysosomes. The movement of lysosomes to the cell surface in response to environmental cues increases the secretion of proteinases and cell invasion. We determined that Troglitazone and other members of the Thiazolidinedione family inhibit cell-surface directed lysosome trafficking and cathepsin B secretion through a Rab7-dependent mechanism. Moreover, Rab7 shRNA expressing cells were found to be more invasive in vitro and in vivo. Increased invasiveness was accompanied by elevated expression of the c-Met receptor and prolonged downstream signaling, thereby supporting a role for Rab7 as a mediator of signaling down-regulation. Taken together, these results suggested that Rab7 acts as a negative regulator of prostate tumor growth and invasion, providing further evidence for its potential as a tumor suppressor.

Precursors and pathogenesis of ovarian carcinoma

The ultimate goal of defining cancer specific precursors is to facilitate early detection and intervention before the development of invasive malignancy. Unlike other malignancies involving the female genital tract such as cervical or endometrial carcinomas, precursor lesions of ovarian carcinomas have not been well characterised, resulting in a failure to develop effective screening programs. Recent clinicopathological and molecular studies have provided new insight into the origin and pathogenesis of ovarian carcinomas. It has been shown that ovarian cancer is comprised of different tumour types differing not only in morphology, but also in pathogenesis, molecular alterations and clinical progression. A dualistic model of ovarian carcinogenesis has been proposed. Type I tumours which include low grade serous, low grade endometrioid, clear cell, mucinous carcinomas and Brenner tumours, are generally indolent and tend to be genetically stable, although clear cell carcinoma would probably belong to an intermediate category. They demonstrate a step-wise progression from a benign precursor such as a benign to borderline tumour or endometriosis and are characterised by genetic aberrations targeting specific cell signalling pathways. Type II tumours comprise high grade serous, high grade endometrioid, and undifferentiated carcinomas as well as malignant mixed mesodermal tumours. They are clinically aggressive and exhibit high genetic instability with frequent p53 mutations. Mounting evidence suggests that many high grade serous carcinomas originate from the epithelium of the distal fallopian tube, and that serous tubal intraepithelial carcinoma (STIC) represents the putative precursor of these neoplasms. Low grade serous carcinomas arise via transformation of benign and borderline serous tumours, thought to be derived from inclusion cysts originating from the ovarian surface or tubal epithelium. Recently it has been suggested that papillary tubal hyperplasia may be a putative precursor lesion for serous borderline tumours. Both endometrioid and clear cell carcinomas develop from endometriosis, via alterations affecting different genetic pathways. The origin of mucinous and transitional cell neoplasms is not well characterised, although new data suggest a possible origin from transitional cell nests present at the tubal-mesothelial junction. Likewise, the pathogenesis of carcinosarcomas is also not well established because of their rarity but there is accumulating evidence that the carcinomatous component determines the course of the disease and gives rise to the malignant mesenchymal component. This review discusses recent developments in the pathogenesis of ovarian carcinoma, with particular emphasis on the putative precursor lesions that give rise to the major histological subtypes. Recognition of these lesions is not only important in improving the understanding of ovarian carcinogenesis, but it will also influence our approach to prevent, detect and treat these tumours.

Plasma endothelial protein C receptor influences innate immune response in ovarian cancer by decreasing the population of natural killer and TH17 helper cells

In spite of the growing importance of endothelial protein C receptor/active protein C (EPCR/aPC) in tumor biology, their impact on immunological homeostasis remains largely unexplored. The objective of this study was to assess whether soluble plasma endothelial protein C receptor (sEPCR), which is a regulator of circulating aPC, is involved in innate immune response in cancer patients. In the Ovcar-3 ovarian cancer line, the role of aPC in secretion of cytokines was analyzed. In parallel, in 33 patients, with a diagnosis of ovarian epithelial cancer, sEPCR was quantified, blood immune cell phenotypes were determined by flow cytometry and plasma cytokines were evaluated using a protein array. Spearman’s rank correlation coefficients (r) and coefficient significance was determined by a statistical hypothesis test (α=0.05). Our results show that i) aPC induced the secretion of several cytokines in Ovcar-3 cells; ii) 61% of patients exhibited a concentration of plasma sEPCR well above the baseline (normal plasma level, 100±28 ng/ml); iii) comparing immune cell phenotypes in patients having a normal level of sEPCR with those having a high level of sEPCR, it was found that sEPCR levels were correlated with high intensity of cells expressing CD45ra, CD3, CD8, CD25 and low intensity of cells expressing CD56 (NK cells), CD294 (TH2 cells), IL-2, IL-10, IL-17a (TH17 cells), IL-21 (TH21 cells) and CD29 markers (r ≥0.60); and iv) high levels of sEPCR correlate with high levels of plasma bioactive proteins such as insulin-like growth factor-2 (IGFII), IL-13rα, macrophage inflammatory protein (MIP1α) and matrix metalloproteinase-7 (MMP-7) that have already been proposed as biomarkers for ovarian cancer and particularly those with poor prognosis. In conclusion, sEPCR produced by ovarian cancer cells, by modulating circulating aPC, influences the secretory behavior of tumor cells (cytokines and interleukins). Consequently, sEPCR in turn acts on the innate immune response by decreasing effector cells such as natural killer and T helper cells (TH2, TH17 and TH21).

Rab25 in cancer: a brief update

Derailed endocytosis is a hallmark of cancer. The endocytic pathway, as demonstrated by our laboratory, is a frequent target of genomic aberrations in cancer and plays a critical role in the maintenance of cellular polarity, stem cell function, bioenergetics, proliferation, motility, invasion, metastasis, apoptosis and autophagy. The Rab GTPases, along with their effectors, are critical regulators of this endocytic machinery and can have a huge impact on the cellular itinerary of growth and metabolism. Rab25 is an epithelial-cell-specific member of the Rab GTPase superfamily, sharing close homology with Rab11a, the endosomal recycling Rab GTPase. RAB25 has been implicated in various cancers, with reports presenting it as both an oncogene and a tumour-suppressor gene. At the cellular level, Rab25 was shown to contribute to invasiveness of cancer cells by regulating integrin trafficking. Recently, our laboratory uncovered a critical role for Rab25 in cellular energetics. Assimilating all of the existing evidence, in the present review, we give an updated overview of the complex and often context-dependent role of Rab25 in cancer.

MUC4 as a diagnostic marker in cancer

BACKGROUND

Mucins are high molecular mass glycoproteins whose role in diagnosis, prognosis and therapy is being increasingly recognized owing to their altered expression in a variety of carcinomas. MUC4, a membrane-bound mucin encoded by a gene located on chromosome locus 3q29, is aberrantly expressed in several cancers including those of the bile duct, breast, colon, esophagus, ovary, lung, prostate, stomach and pancreas.

OBJECTIVE

This review considers the potential use of the MUC4 expression pattern in the diagnosis and prognosis of various cancers.

RESULTS/CONCLUSION

MUC4 expression is a specific marker of epithelial tumors and its expression correlates positively with the degree of differentiation in several cancers. Importantly, MUC4 has emerged as a specific marker of dysplasia, being expressed in the earliest dysplastic lesions preceding several malignancies, including lethal pancreatic cancer. The presence of MUC4-specific antibodies in the serum and of the transcript in peripheral blood mononuclear cells of cancer patients raises the possibility of it emerging as a new diagnostic biomarker for bedside application in high-risk individuals and those with established cancer.

Expression of ESE-3 isoforms in immunogenic and tolerogenic human monocyte-derived dendritic cells

Dendritic cells (DC) are the only hematopoietic cells expressing the epithelial specific Ets transcription factor ESE-3. Here we analyzed presence and quantity of isoforms ESE-3a, ESE-3b and ESE-3j in various immunogenic and tolerogenic human monocyte-derived DC (moDC) and blood DC populations using quantitative real time PCR and immunoblot analyses. ESE-3a and ESE-3b were detectable in all moDC populations with ESE-3b being the main transcript. ESE-3b expression was upregulated in immunogenic moDC and downregulated in tolerogenic moDC compared to immature moDC. ESE-3a had similar transcript levels in immature and immunogenic moDC and had very low levels in tolerogenic moDC. In blood DC populations only splice variant ESE-3b was detectable. ESE-3j was not detectable in any of the DC populations. These findings suggest that ESE-3b is the functionally most important ESE-3 isoform in DC.

Migfilin, α-parvin and β-parvin are differentially expressed in ovarian serous carcinoma effusions, primary tumors and solid metastases

OBJECTIVE

The objective of this study is to analyze the expression and clinical role of integrin-linked kinase (ILK), α-parvin, β-parvin and migfilin in advanced-stage serous ovarian carcinoma.

METHODS

Expression of these 4 proteins was investigated in 205 effusions and in 94 patient-matched solid lesions (33 primary tumors and 61 solid metastases) using immunohistochemistry. Protein expression was analyzed for association with clinicopathologic parameters and survival.

RESULTS

ILK, α-parvin, β-parvin and migfilin were expressed in tumor cells in 53%, 2%, 28% and 53% of effusions and 57%, 20%, 83% and 25% of solid lesions, respectively. Statistical analysis showed significantly higher α-parvin and β-parvin expression in primary carcinomas (p=0.02 and p=0.001, respectively) and solid metastases (p=0.001 and p<0.001, respectively), compared to effusions, with opposite findings for migfilin (p=0.006 and p=0.008 for primary carcinomas and solid metastases, respectively). ILK expression was comparable at all anatomic sites. β-Parvin expression in effusions was associated with better response to chemotherapy at diagnosis (p=0.014), with no other significant association with clinicopathologic parameters or survival. Expression in primary tumors and solid metastases was similarly unrelated to clinicopathologic parameters or survival.

CONCLUSIONS

This study provides further evidence to our previous observations that the adhesion profile of ovarian serous carcinoma cells in effusions differs from their counterparts in primary carcinomas and solid metastases. β-Parvin may be a novel marker of chemoresponse in metastatic ovarian carcinoma.

Increased Rab25 expression is not correlated with peritoneal metastasis of ovarian cancers

Ovarian cancer is the leading cause of death in gynecological cancer. Studies suggested Rab25 is involved in the pathogenesis of ovarian cancers. We here investigated the expression of Rab25 is in all ovarian cancers and whether the expression of Rab25 is associated with peritoneal metastasis. Fifty-nine ovarian cancer patients were included and the levels of Rab25 measured by immunohistochemistry. Our data showed Rab25 was highly expressed in all subtypes of epithelial ovarian cancers, and two subtypes of germ cell tumors, but not in sex cord stromal tumors. Furthermore, the Rab25 expression was not correlated with peritoneal metastasis of ovarian cancer.

Perturbation of Rb, p53, and Brca1 or Brca2 cooperate in inducing metastatic serous epithelial ovarian cancer

The majority of human high-grade serous epithelial ovarian cancer (SEOC) is characterized by frequent mutations in p53 and alterations in the RB and FOXM1 pathways. A subset of human SEOC harbors a combination of germline and somatic mutations as well as epigenetic dysfunction for BRCA1/2. Using Cre-conditional alleles and intrabursal induction by Cre-expressing adenovirus in genetically engineered mice, we analyzed the roles of pathway perturbations in epithelial ovarian cancer initiation and progression. Inactivation of RB-mediated tumor suppression induced surface epithelial proliferation with progression to stage I carcinoma. Additional biallelic inactivation and/or missense p53 mutation in the presence or absence of Brca1/2 caused progression to stage IV disease. As in human SEOC, mice developed peritoneal carcinomatosis, ascites, and distant metastases. Unbiased gene expression and metabolomic profiling confirmed that Rb, p53, and Brca1/2-triple mutant tumors aligned with human SEOC, and not with other intraperitoneal cancers. Together, our findings provide a novel resource for evaluating disease etiology and biomarkers, therapeutic evaluation, and improved imaging strategies in epithelial ovarian cancer.

Molecular markers associated with nonepithelial ovarian cancer in formalin-fixed, paraffin-embedded specimens by genome wide expression profiling

Nonepithelial ovarian cancer (NEOC) is a rare cancer that is often misdiagnosed as other malignant tumors. Research on this cancer using fresh tissues is nearly impossible because of its limited number of samples within a limited time provided. The study is to identify potential genes and their molecular pathways related to NEOC using formalin-fixed paraffin embedded samples. Total RNA was extracted from eight archived NEOCs and seven normal ovaries. The RNA samples with RNA integrity number >2.0, purity >1.7 and cycle count value <28 cycles were hybridized to the Illumina Whole-Genome DASL assay (cDNA-mediated annealing, selection, extension, and ligation). We analyzed the results using the GeneSpring GX11.0 and FlexArray software to determine the differentially expressed genes. Microarray results were validated using an immunohistochemistry method. Statistical analysis identified 804 differentially expressed genes with 443 and 361 genes as overexpressed and underexpressed in cancer, respectively. Consistent findings were documented for the overexpression of eukaryotic translation elongation factor 1 alpha 1, E2F transcription factor 2, and fibroblast growth factor receptor 3, except for the down-regulated gene, early growth response 1 (EGR1). The immunopositivity staining for EGR1 was found in the majority of cancer tissues. This finding suggested that the mRNA level of a transcript did not always match with the protein expression in tissues. The current gene profile can be the platform for further exploration of the molecular mechanism of NEOC.

Epithelial-mesenchymal transition in ovarian carcinoma

Ovarian cancer is the most lethal gynecologic malignancy, with the majority of patients dying within 5 years of diagnosis. This poor survival of patients diagnosed with this malignancy is attributed to diagnosis at advanced stage, when the tumor has metastasized, and to chemotherapy resistance, either primary or developing along tumor progression. However, ovarian carcinomas, constituting the vast majority of ovarian cancers, additionally have unique biology, one aspect of which is the ability to co-express epithelial and mesenchymal determinants. epithelial–mesenchymal transition (EMT), a physiological process by which mesenchymal cells are formed and migrate to target organs during embryogenesis, is involved in cancer cell invasion and metastasis. However, these changes do not fully occur in ovarian carcinoma, and are even reversed in tumor cells present in malignant peritoneal and pleural effusions. This review summarizes current knowledge in this area, including the characteristics of EMT related to adhesion, transcriptional regulation and chemoresistance, and their clinical relevance, as well as the recently observed regulation of EMT by microRNA.

PRAME (preferentially expressed antigen of melanoma) is a novel marker for differentiating serous carcinoma from malignant mesothelioma

The PRAME (preferentially expressed antigen of melanoma) gene was previously shown to be overexpressed in ovarian/primary peritoneal serous carcinoma compared with malignant mesothelioma using gene expression arrays. The objective of this study was to validate this finding at the messenger RNA (mRNA) and protein levels. Quantitative real-time polymerase chain reaction analysis of 126 müllerian carcinomas and 23 malignant mesotheliomas showed significantly higher PRAME mRNA expression in the former tumor (P < .001; test sensitivity and specificity, 89% and 91%, respectively). PRAME protein was expressed in 41 of 50 müllerian carcinomas and 0 of 30 mesotheliomas using Western blotting (P < .001; test sensitivity and specificity, 82% and 100%, respectively). PRAME levels in müllerian carcinoma were unrelated to survival; however, PRAME protein expression was up-regulated in solid metastases compared with primary carcinoma and effusions (P < .001). Our data confirm that PRAME effectively differentiates müllerian carcinoma from malignant mesothelioma at the mRNA and protein levels, suggesting a role in the diagnostic workup of serosal cancers.

Gene expression signatures differentiate adenocarcinoma of lung and breast origin in effusions

Lung and breast adenocarcinoma at advanced stages commonly involve the serosal cavities, giving rise to malignant effusions. The aim of the present study was to compare the global gene expression patterns of metastases from these 2 malignancies, to expand and improve the diagnostic panel of biomarkers currently available for their differential diagnosis, as well as to define type-specific biological targets. Gene expression profiles of 7 breast and 4 lung adenocarcinoma effusions were analyzed using the HumanRef-8 BeadChip from Illumina. Differentially expressed candidate genes were validated using quantitative real-time polymerase chain reaction and immunohistochemistry. Unsupervised hierarchical clustering using all 54,675 genes in the array separated lung from breast adenocarcinoma samples. We identified 289 unique probes that were significantly differentially expressed in the 2 cancers by greater than 2-fold using moderated t statistics, of which 65 and 224 were overexpressed in breast and lung adenocarcinoma, respectively. Genes overexpressed in breast adenocarcinoma included TFF1, TFF3, FOXA1, CA12, PITX1, RARRES1, CITED4, MYC, TFAP2A, EFHD1, TOB1, SPDEF, FASN, and TH. Genes overexpressed in lung adenocarcinoma included TITF1, SFTPG, MMP7, EVA1, GPR116, HOP, SCGB3A2, and MET. The differential expression of 15 genes was validated by quantitative real-time PCR, and differences in 8 gene products were confirmed by immunohistochemistry. Expression profiling distinguishes breast adenocarcinoma from lung adenocarcinoma and identifies genes that are differentially expressed in these 2 tumor types. The molecular signatures unique to these cancers may facilitate their differential diagnosis and may provide a molecular basis for therapeutic target discovery.

Expression of the Ets transcription factor EHF in serous ovarian carcinoma effusions is a marker of poor survival

The EHF (Ets homologous factor) gene was previously shown to be overexpressed in ovarian/primary peritoneal serous carcinoma compared to malignant mesothelioma using gene expression arrays. The objective of this study was to validate this finding at the mRNA level in a larger series. We analyzed the diagnostic role of EHF in 98 ovarian serous carcinoma effusions, 23 malignant mesothelioma specimens (20 effusions, 3 surgical specimens), and 28 primary ovarian serous carcinomas using quantitative real-time polymerase chain reaction. Expression levels of EHF in ovarian carcinoma were additionally investigated for association with clinicopathologic parameters and survival. Quantitative real-time polymerase chain reaction analysis showed significantly higher expression of EHF mRNA in ovarian carcinoma effusions and in primary ovarian carcinoma compared to malignant mesothelioma effusions (P < .001 for both). EHF mRNA expression was additionally higher in primary ovarian carcinomas compared to effusions of this cancer (P < .001). In univariate analysis for all patients with effusions, higher EHF mRNA levels were associated with a trend for shorter progression-free survival (P = .066), which became significant in analysis of 45 patients with primary diagnosis pre-chemotherapy effusions (P = .01). In Cox multivariate analysis, EHF mRNA expression was an independent predictor of poor progression-free survival for all patients and patients with primary diagnosis pre-chemotherapy effusions (P = .033 and P = .009, respectively). EHF mRNA levels differentiate ovarian carcinoma from malignant mesothelioma and may thus be of diagnostic value in this setting. EHF may be a novel prognostic marker in ovarian carcinoma.

Gene expression signatures differentiate ovarian/peritoneal serous carcinoma from breast carcinoma in effusions

Ovarian/primary peritoneal carcinoma and breast carcinoma are the gynaecological cancers that most frequently involve the serosal cavities.With the objective of improving on the limited diagnostic panel currently available for the differential diagnosis of these two malignancies,as well as to define tumour-specific biological targets, we compared their global gene expression patterns. Gene expression profiles of 10 serous ovarian/peritoneal and eight ductal breast carcinoma effusions were analysed using the HumanRef-8 BeadChip from Illumina.Differentially expressed candidate genes were validated using quantitative real-time PCR and immunohistochemistry. Unsupervised hierarchical clustering using all 54,675 genes in the array separated ovarian from breast carcinoma samples. We identified 288 unique probes that were significantly differentially expressed in the two cancers by greater than 3.5-fold, of which 81 and 207 were overexpressed in breast and ovarian/peritoneal carcinoma, respectively. SAM analysis identified 1078 differentially expressed probes with false discovery rate less than 0.05. Genes overexpressed in breast carcinoma included TFF1, TFF3, FOXA1, CA12, GATA3, SDC1, PITX1, TH, EHFD1, EFEMP1, TOB1 and KLF2. Genes overexpressed in ovarian/peritoneal carcinoma included SPON1, RBP1, MFGE8, TM4SF12, MMP7, KLK5/6/7, FOLR1/3,PAX8, APOL2 and NRCAM. The differential expression of 14 genes was validated by quantitative real-time PCR, and differences in 5 gene products were confirmed by immunohistochemistry. Expression profiling distinguishes ovarian/peritoneal carcinoma from breast carcinoma and identifies genes that are differentially expressed in these two tumour types. The molecular signatures unique to these cancers may facilitate their differential diagnosis and may provide a molecular basis for therapeutic target discovery.

Gene expression signatures differentiate ovarian/peritoneal serous carcinoma from breast carcinoma in effusions

Ovarian/primary peritoneal carcinoma and breast carcinoma are the gynaecological cancers that most frequently involve the serosal cavities. With the objective of improving on the limited diagnostic panel currently available for the differential diagnosis of these two malignancies, as well as to define tumour-specific biological targets, we compared their global gene expression patterns. Gene expression profiles of 10 serous ovarian/peritoneal and eight ductal breast carcinoma effusions were analysed using the HumanRef-8 BeadChip from Illumina. Differentially expressed candidate genes were validated using quantitative real-time PCR and immunohistochemistry. Unsupervised hierarchical clustering using all 54,675 genes in the array separated ovarian from breast carcinoma samples. We identified 288 unique probes that were significantly differentially expressed in the two cancers by greater than 3.5-fold, of which 81 and 207 were overexpressed in breast and ovarian/peritoneal carcinoma, respectively. SAM analysis identified 1078 differentially expressed probes with false discovery rate less than 0.05. Genes overexpressed in breast carcinoma included TFF1, TFF3, FOXA1, CA12, GATA3, SDC1, PITX1, TH, EHFD1, EFEMP1, TOB1 and KLF2. Genes overexpressed in ovarian/peritoneal carcinoma included SPON1, RBP1, MFGE8, TM4SF12, MMP7, KLK5/6/7, FOLR1/3, PAX8, APOL2 and NRCAM. The differential expression of 14 genes was validated by quantitative real-time PCR, and differences in 5 gene products were confirmed by immunohistochemistry. Expression profiling distinguishes ovarian/peritoneal carcinoma from breast carcinoma and identifies genes that are differentially expressed in these two tumour types. The molecular signatures unique to these cancers may facilitate their differential diagnosis and may provide a molecular basis for therapeutic target discovery.