Identification of overexpression and amplification of ABCF2 in clear cell ovarian adenocarcinomas by cDNA microarray analyses

Modular Design Platform for Activatable Fluorescence Probes Targeting Carboxypeptidases Based on ProTide Chemistry

Carboxypeptidases (CPs) are a family of hydrolases that cleave one or more amino acids from the C-terminal of peptides or proteins and play indispensable roles in various physiological and pathological processes. However, only a few highly activatable fluorescence probes for CPs have been reported, and there is a need for a flexibly tunable molecular design platform to afford a range of fluorescence probes for CPs for biological and medical research. Here, we focused on the unique activation mechanism of ProTide-based prodrugs and established a modular design platform for CP-targeting florescence probes based on ProTide chemistry. In this design, probe properties such as fluorescence emission wavelength, reactivity/stability, and target CP can be readily tuned and optimized by changing the four probe modules: the fluorophore, the substituent on the phosphorus atom, the linker amino acid at the P1 position, and the substrate amino acid at the P1' position. In particular, switching the linker amino acid at position P1 enabled us to precisely optimize the reactivity for target CPs. As a proof-of-concept, we constructed probes for carboxypeptidase M (CPM) and prostate-specific membrane antigen (also known as glutamate carboxypeptidase II). The developed probes were applicable for the imaging of CP activities in live cells and in clinical specimens from patients. This design strategy should be useful in studying CP-related biological and pathological phenomena.

Fluorescence Probes for Imaging Basic Carboxypeptidase Activity in Living Cells with High Intracellular Retention

Basic carboxypeptidases (basic CPs) cleave the C-terminal basic amino acid of peptides, and their activity is upregulated in some types of cancers. Therefore, detecting the activity of basic CPs in living cells would be important not only for studying the physiological functions of these enzymes but also for visualization of cancerous tissues. Here, we report two fluorescein diacetate (FDA)-based activatable fluorescence probes, named 5ArgAF-FDA and 5LysAF-FDA, in which the substrate amino acid arginine or lysine is conjugated to the benzene moiety via an azoformyl linker. In live-cell fluorescence imaging of CPM, one of the seven basic CPs, 5ArgAF-FDA showed a larger intracellular fluorescence increase than did 5LysAF-FDA within a few minutes. This increase was inhibited by coincubation with 2-mercaptomethyl-3-guanidinoethylthiopropanoic acid (MGTA), an inhibitor of basic CPs. When 5ArgAF-FDA was applied to a coculture of two breast cancer cell lines with different CPM activities, the fluorescence increase in individual cells was correlated with the expression level of CPM, suggesting that 5ArgAF-FDA has the ability to distinguish cell lines having different levels of CPM activity, owing to its high intracellular retention. We believe these probes will be useful for imaging cancers with upregulated basic CP activity.

Association of ABC gene profiles with time to progression and resistance in ovarian cancer revealed by bioinformatics analyses

Introduction

Ovarian cancer (OC) represents a serious disease with high mortality and lack of efficient predictive and prognostic biomarkers. ATP‐binding cassette (ABC) proteins constitute a large family dedicated to active transmembrane transport including transport of xenobiotics.

Materials and methods

mRNA level was measured by quantitative RT‐PCR in tumor tissues from OC patients. Bioinformatics analyses were applied to two gene expression datasets (60 primary tumors and 29 peritoneal metastases). Two different approaches of expression data normalization were applied in parallel, and their results were compared. Data from publically available cancer datasets were checked to further validate our conclusions.

Results

The results showed significant connections between ABC gene expression profiles and time to progression (TTP), chemotherapy resistance, and metastatic progression in OC. Two consensus ABC gene profiles with clinical meaning were documented. (a) Downregulation of ABCC4, ABCC10, ABCD3, ABCE1, ABCF1, ABCF2, and ABCF3 was connected with the best sensitivity to chemotherapy and TTP. (b) Oppositely, downregulation of ABCB11 and upregulation of ABCB1 and ABCG2 were connected with the worst sensitivity to chemotherapy and TTP. Results from publicly available online databases supported our conclusions.

Conclusion

This study stressed the connection between two well‐documented ABC genes and clinicopathological features—ABCB1 and ABCG2. Moreover, we showed a comparable connection also for several other ABC genes—ABCB11, ABCC4, ABCC10, ABCD3,ABCE1, ABCF1, ABCF2, and ABCF3. Our results add new clinically relevant information to this oncology field and can stimulate further exploration.

Polyene phosphatidylcholine overcomes oxaliplatin resistance in human gastric cancer BGC823 cells

Intrinsic or acquired resistance to oxaliplatin (L-OHP) is a major reason of treatment failure in gastric cancer and limits therapeutic success. Here we generated an oxaliplatin resistant gastric cancer cell line, BGC823/L-OHP, to investigate the effect of a hepatoprotective compound, polyene phosphatidylcholine (PPC), on conquest of oxaliplatin resistance. BGC823/L-OHP cells showed less sensitive to L-OHP directed growth inhibition than the parental BGC823 cells. PPC treatment significantly increased anti-proliferative activity of L-OHP on resistant cells and promoted L-OHP triggered apoptosis, indicating that drug resistance was overcome. Mechanistically, L-OHP incubation stimulated upregulation of an ABC family protein, ABCF2, and the expression was inhibited by PPC. Moreover, expression levels of the stemness factor Nanog and its regulator TLR4 were notably enhanced in BGC823/L-OHP cells and reduced by PPC treatment. To conclude, PPC can overcome oxaliplatin resistance in gastric cancer cells via promoting apoptosis, inhibiting ABCF2, as well via reducing cancer stem cell-like features. The combination therapeutic strategy could serve to increase oxaliplatin effectiveness in the clinic.

ADAM9 is over-expressed in human ovarian clear cell carcinomas and suppresses cisplatin-induced cell death

ADAMs (a disintegrin and metalloproteinases) are involved in various biological events such as cell adhesion, migration and invasion, membrane protein shedding and proteolysis. However, there have been no systematic studies on the expression of ADAMs in human ovarian carcinomas. We therefore examined mRNA expression of all the proteolytic ADAM species including ADAM8, 9, 10, 12, 15, 17, 19, 20, 21, 28, 30, 33 and ADAMDEC1 in human ovarian carcinomas, and found that prototype membrane-anchored ADAM9m, but not secreted isoform ADAM9s, is significantly over-expressed in carcinomas than in control non-neoplastic ovarian tissue. Among the histological subtypes of serous, endometrioid, mucinous and clear cell carcinomas, ADAM9m expression was highest in clear cell carcinomas. Immunohistochemistry showed that all the clear cell carcinoma samples displayed ADAM9m primarily on the carcinoma cell membrane. By immunoblotting, ADAM9m was detected mainly in an active form in the clear cell carcinoma tissues. When two clear cell carcinoma cell lines (RMG-I and TOV21G cells) with ADAM9m expression were treated with cisplatin, viability was significantly reduced and apoptosis increased in ADAM9m knockdown cells compared with mock transfectants. In addition, treatment of the cells with neutralizing anti-ADAM9m antibody significantly decreased viability compared with non-immune IgG, whereas ADAM9m over-expression significantly increased viability compared with mock transfectants. Our data show, to the best of our knowledge, for the first time, that ADAM9m is over-expressed in an activated form in human ovarian clear cell carcinomas, and suggest that ADAM9m plays a key role in cisplatin resistance.

Ovarian Cancers: Genetic Abnormalities, Tumor Heterogeneity and Progression, Clonal Evolution and Cancer Stem Cells

Four main histological subtypes of ovarian cancer exist: serous (the most frequent), endometrioid, mucinous and clear cell; in each subtype, low and high grade. The large majority of ovarian cancers are diagnosed as high-grade serous ovarian cancers (HGS-OvCas). TP53 is the most frequently mutated gene in HGS-OvCas; about 50% of these tumors displayed defective homologous recombination due to germline and somatic BRCA mutations, epigenetic inactivation of BRCA and abnormalities of DNA repair genes; somatic copy number alterations are frequent in these tumors and some of them are associated with prognosis; defective NOTCH, RAS/MEK, PI3K and FOXM1 pathway signaling is frequent. Other histological subtypes were characterized by a different mutational spectrum: LGS-OvCas have increased frequency of BRAF and RAS mutations; mucinous cancers have mutation in ARID1A, PIK3CA, PTEN, CTNNB1 and RAS. Intensive research was focused to characterize ovarian cancer stem cells, based on positivity for some markers, including CD133, CD44, CD117, CD24, EpCAM, LY6A, ALDH1. Ovarian cancer cells have an intrinsic plasticity, thus explaining that in a single tumor more than one cell subpopulation, may exhibit tumor-initiating capacity. The improvements in our understanding of the molecular and cellular basis of ovarian cancers should lead to more efficacious treatments.

Chorioamnionitis Induces a Specific Signature of Placental ABC Transporters Associated with an Increase of miR-331-5p in the Human Preterm Placenta

Background/Aims

The ATP-binding cassette (ABC) transporters mediate drug biodisposition and immunological responses in the placental barrier. In vitro infective challenges alter expression of specific placental ABC transporters. We hypothesized that chorioamnionitis induces a distinct pattern of ABC transporter expression.

Methods

Gene expression of 50 ABC transporters was assessed using TaqMan® Human ABC Transporter Array, in preterm human placentas without (PTD; n=6) or with histological chorioamnionitis (PTDC; n=6). Validation was performed using qPCR, immunohistochemistry and Western blot. MicroRNAs known to regulate P-glycoprotein (P-gp) were examined by qPCR.

Results

Up-regulation of ABCB9, ABCC2 and ABCF2 mRNA was detected in chorioamnionitis (p<0.05), whereas placental ABCB1 (P-gp; p=0.051) and ABCG2 (breast cancer resistance protein-BCRP) mRNA levels (p=0.055) approached near significant up-regulation. In most cases, the magnitude of the effect significantly correlated to the severity of inflammation. Upon validation, increased placental ABCB1 and ABCG2 mRNA levels (p<0.05) were observed. At the level of immunohistochemistry, while BCRP was increased (p<0.05), P-gp staining intensity was significantly decreased (p<0.05) in PTDC. miR-331-5p, involved in P-gp suppression, was upregulated in PTDC (p<0.01) and correlated to the grade of chorioamnionitis (p<0.01).

Conclusions

Alterations in the expression of ABC transporters will likely lead to modified transport of clinically relevant compounds at the inflamed placenta. A better understanding of the potential role of these transporters in the events surrounding PTD may also enable new strategies to be developed for prevention and treatment of PTD.

The role of membrane transporters in ovarian cancer chemoresistance and prognosis

INTRODUCTION

Ovarian cancer has the highest mortality rate of all cancers in women. There is currently no effective method for early diagnosis, limiting the precision of clinical expectations. Predictions of therapeutic efficacy are currently not available either. Specifically, the development of chemoresistance against conventional chemotherapy poses a fundamental complication. Some membrane transporters have been reported to influence chemoresistance, which is often associated with a poor prognosis. Areas covered: The aim of this article is to review the existing information about membrane transporters and their role in both ovarian cancer chemoresistance and its outcomes. We then highlight limitations of current methodologies and suggest alternatives providing avenues for future research. Expert opinion: Membrane transporters play an important role in development of chemoresistance and affect prognosis of ovarian cancer patients; however, due to variations in methodology and in patient populations, their specific roles have yet to be clarified. For further evaluation of the clinical utility of membrane transporters, it is essential to validate results and improve methods for marker assessment across laboratories. A promising area for future research is to identify the genetic variability in potential markers in peripheral blood. These markers would then stratify patients into defined groups for optimal intervention.

ABCF2, an Nrf2 target gene, contributes to cisplatin resistance in ovarian cancer cells

Previously, we have demonstrated that NRF2 plays a key role in mediating cisplatin resistance in ovarian cancer. To further explore the mechanism underlying NRF2-dependent cisplatin resistance, we stably overexpressed or knocked down NRF2 in parental and cisplatin-resistant human ovarian cancer cells, respectively. These two pairs of stable cell lines were then subjected to microarray analysis, where we identified 18 putative NRF2 target genes. Among these genes, ABCF2, a cytosolic member of the ABC superfamily of transporters, has previously been reported to contribute to chemoresistance in clear cell ovarian cancer. A detailed analysis on ABCF2 revealed a functional antioxidant response element (ARE) in its promoter region, establishing ABCF2 as an NRF2 target gene. Next, we investigated the contribution of ABCF2 in NRF2-mediated cisplatin resistance using our stable ovarian cancer cell lines. The NRF2-overexpressing cell line, containing high levels of ABCF2, was more resistant to cisplatin-induced apoptosis compared to its control cell line; whereas the NRF2 knockdown cell line with low levels of ABCF2, was more sensitive to cisplatin treatment than its control cell line. Furthermore, transient overexpression of ABCF2 in the parental cells decreased apoptosis and increased cell viability following cisplatin treatment. Conversely, knockdown of ABCF2 using specific siRNA notably increased apoptosis and decreased cell viability in cisplatin-resistant cells treated with cisplatin. This data indicate that the novel NRF2 target gene, ABCF2, plays a critical role in cisplatin resistance in ovarian cancer, and that targeting ABCF2 may be a new strategy to improve chemotherapeutic efficiency.

Novel biomarker candidates for the diagnosis of ovarian clear cell carcinoma

Ovarian clear cell carcinoma can arise from endometriosis; however, it is distinct from other types of epithelial ovarian carcinoma in terms of its clinicopathological and molecular features. Cancer antigen 125 lacks the sensitivity and specificity required for accurate clinical diagnosis of clear cell carcinoma. Therefore, the aim of the current review was to identify novel biomarker candidates for the immunohistochemical and serological diagnosis of clear cell carcinoma. A search of the relevant English language literature published between 1966 and 2014 was conducted using the PubMed MEDLINE online database. High-throughput tissue microarray technology and proteomic screening combined with mass spectrometry may provide additional information regarding diagnostic biomarker candidates for ovarian clear cell carcinoma. The present review summarizes the characteristics of potential genomic alterations that activate cancer signaling pathways and, thus, contribute to carcinogenesis. The major signaling pathways activated in clear cell carcinoma are associated with cell cycle regulation (hepatitis A virus cellular receptor 1 and tumor protein D52), growth factor signaling (insulin-like growth factor binding protein 1; KiSS-1 metastasis-suppressor; erb-b2 receptor tyrosine kinase 2; and fibroblast growth factor receptor 2), anti-apoptosis and survival pathways [sialidase 3 (membrane sialidase)], metabolism (γ-glutamyltransferase 1), chemoresistance (napsin A aspartic peptidase, glutathione peroxidase 3; and aldehyde dehydrogenase 1 family, member A1), coagulation [coagulation factor III (thromboplastin, tissue factor); and tissue factor pathway inhibitor 2], signaling (lectin, galactoside-binding and soluble, 3), and adhesion and the extracellular matrix [cadherin 1, type 1, E-cadherin (epithelial); versican; and laminin, α 5]. The present review of the relevant literature may provide a basis for additional clinical investigation of the ovarian clear cell carcinoma serum biomarker candidate proteins identified herein.

The role of ABC transporters in ovarian cancer progression and chemoresistance

Over 80% of ovarian cancer patients develop chemoresistance which results in a lethal course of the disease. A well-established cause of chemoresistance involves the family of ATP-binding cassette transporters, or ABC transporters that transport a wide range of substrates including metabolic products, nutrients, lipids, and drugs across extra- and intra-cellular membranes. Expressions of various ABC transporters, shown to reduce the intracellular accumulation of chemotherapy drugs, are increased following chemotherapy and impact on ovarian cancer survival. Although clinical trials to date using ABC transporter inhibitors have been disappointing, ABC transporter inhibition remains an attractive potential adjuvant to chemotherapy. A greater understanding of their physiological functions and role in ovarian cancer chemoresistance will be important for the development of more effective targeted therapies. This article will review the role of the ABC transporter family in ovarian cancer progression and chemoresistance as well as the clinical attempts used to date to reverse chemoresistance.

Checkpoint kinase 1 inhibitors as targeted molecular agents for clear cell carcinoma of the ovary

In clear cell carcinoma of the ovary, chemoresistance frequently results in treatment failure. The present study aimed to review the potential association of transcription factor hepatocyte nuclear factor (HNF)-1β with cell cycle checkpoint machinery, as a mechanism for chemoresistance. The English-language literature on the subject was reviewed to identify genomic alterations and aberrant molecular pathways interacting with chemoresistance in clear cell carcinoma. Oxidative stress induced by repeated hemorrhage induces greater susceptibility of endometriotic cells to DNA damage, and subsequent malignant transformation results in endometriosis-associated ovarian cancer. Molecular changes, including those in HNF-1β and checkpoint kinase 1 (Chk1), may be a manifestation of essential alterations in cell cycle regulation, detoxification and chemoresistance in clear cell carcinoma. Chk1 is a critical signal transducer in the cell cycle checkpoint machinery. DNA damage, in turn, increases persistent phosphorylation of Chk1 and induction of G2/M phase cell cycle arrest in cells overexpressing HNF-1β. HNF-1β deletion induces apoptosis, suggesting that enhanced levels of HNF-1β may be associated with chemoresistance. Targeted therapy with Chk1 inhibitors may be explored as a potential treatment modality for patients with clear cell carcinoma. This provides a novel direction for combination therapy, including targeting of Chk1, which may overcome drug resistance and improve treatment efficacy.

ABC transporters and neuroblastoma

Neuroblastoma is the most common cancer of infancy and accounts for 15% of all pediatric oncology deaths. Survival rates of high-risk neuroblastoma remain less than 50%, with amplification of the MYCN oncogene the most important aberration associated with poor outcome. Direct transcriptional targets of MYCN include a number of ATP-binding cassette (ABC) transporters, of which ABCC1 (MRP1), ABCC3 (MRP3), and ABCC4 (MRP4) are the best characterized. These three transporter genes have been shown to be strongly prognostic of neuroblastoma outcome in primary untreated neuroblastoma. In addition to their ability to efflux a number of chemotherapeutic drugs, evidence suggests that these transporters also contribute to neuroblastoma outcome independent of any role in cytotoxic drug efflux. Endogenous substrates of ABCC1 and ABCC4 that may be potential candidates affecting neuroblastoma biology include molecules such as prostaglandins and leukotrienes. These bioactive lipid mediators have the ability to influence biological processes contributing to cancer initiation and progression, such as angiogenesis, cell signaling, inflammation, proliferation, and migration and invasion. ABCC1 and ABCC4 are thus potential targets for therapeutic suppression in high-risk neuroblastoma, and recently developed small-molecule inhibitors may be an effective strategy in treating aggressive forms of this cancer, as well as other cancers that express high levels of these transporters.

Early targets of miR-34a in neuroblastoma

Several genes encoding for proteins involved in proliferation, invasion, and apoptosis are known to be direct miR-34a targets. Here, we used proteomics to screen for targets of miR-34a in neuroblastoma (NBL), a childhood cancer that originates from precursor cells of the sympathetic nervous system. We examined the effect of miR-34a overexpression using a tetracycline inducible system in two NBL cell lines (SHEP and SH-SY5Y) at early time points of expression (6, 12, and 24 h). Proteome analysis using post-metabolic labeling led to the identification of 2,082 proteins, and among these 186 were regulated (112 proteins down-regulated and 74 up-regulated). Prediction of miR-34a targets via bioinformatics showed that 32 transcripts held miR-34a seed sequences in their 3'-UTR. By combining the proteomics data with Kaplan Meier gene-expression studies, we identified seven new gene products (ALG13, TIMM13, TGM2, ABCF2, CTCF, Ki67, and LYAR) that were correlated with worse clinical outcomes. These were further validated in vitro by 3'-UTR seed sequence regulation. In addition, Michigan Molecular Interactions searches indicated that together these proteins affect signaling pathways that regulate cell cycle and proliferation, focal adhesions, and other cellular properties that overall enhance tumor progression (including signaling pathways such as TGF-β, WNT, MAPK, and FAK). In conclusion, proteome analysis has here identified early targets of miR-34a with relevance to NBL tumorigenesis. Along with the results of previous studies, our data strongly suggest miR-34a as a useful tool for improving the chance of therapeutic success with NBL.

Carboxypeptidase M in apoptosis, adipogenesis and cancer

This review covers carboxypeptidase M (CPM) research that appeared in the literature since 2009. The focus is on aspects that are new or interesting from a clinical perspective. Available research tools are discussed as well as their pitfalls and limitations. Evidence is provided to suggest the potential involvement of CPM in apoptosis, adipogenesis and cancer. This evidence derives from the expression pattern of CPM and its putative substrates in cells and tissues. In recent years CPM emerged as a potential cancer biomarker, in well differentiated liposarcoma where the CPM gene is co-amplified with the oncogene MDM2; and in lung adenocarcinoma where coexpression with EGFR correlates with poor prognosis. The available data call for extended investigation of the function of CPM in tumor cells, tumor-associated macrophages, stromal cells and tumor neovascularisation. Such experiments could be instrumental to validate CPM as a therapeutic target.

Clear cell carcinoma of the ovary: is there a role of histology-specific treatment?

Several clinical trials to establish standard treatment modality for ovarian cancers included a high abundance of patients with serous histologic tumors, which were quite sensitive to platinum-based chemotherapy. On the other hand, ovarian tumor with rare histologic subtypes such as clear cell or mucinous tumors have been recognized to show chemo-resistant phenotype, leading to poorer prognosis. Especially, clear cell carcinoma of the ovary (CCC) is a distinctive tumor, deriving from endometriosis or clear cell adenofibroma, and response rate to platinum-based therapy is extremely low. It was implied that complete surgical staging enabled us to distinguish a high risk group of recurrence in CCC patients whose disease was confined to the ovary (pT1M0); however, complete surgical staging procedures could not lead to improved survival. Moreover, the status of peritoneal cytology was recognized as an independent prognostic factor in early-staged CCC patients, even after complete surgical staging. In advanced cases with CCC, the patients with no residual tumor had significantly better survival than those with the tumor less than 1 cm or those with tumor diameter more than 1 cm. Therefore, the importance of achieving no macroscopic residual disease at primary surgery is so important compared with other histologic subtypes. On the other hand, many studies have shown that conventional platinum-based chemotherapy regimens yielded a poorer prognosis in patients with CCC than in patients with serous subtypes. The response rate by paclitaxel plus carboplatin (TC) was slightly higher, ranging from 22% to 56%, which was not satisfactory enough. Another regimen for CCC tumors is now being explored: irinotecan plus cisplatin, and molecular targeting agents. In this review article, we discuss the surgical issues for early-staged and advanced CCC including possibility of fertility-sparing surgery, and the chemotherapy for CCC disease.

Ovarian cancer stem cell markers: prognostic and therapeutic implications

Cancer stem cells are rare chemotherapy resistant cells within a tumor which can serve to populate the bulk of a tumor with more differentiated daughter cells and potentially contribute to recurrent disease. Ovarian cancer is a disease for which at the time of initial treatment we can obtain complete clinical remission in the majority of patients. Unfortunately, most will relapse and succumb to their disease. This clinical course is in line with the cancer stem cell model. In the past 5 years a significant amount of work has been done to identify cells with characteristics of ovarian cancer stem cells. This review will focus specifically on the markers used to define human ovarian cancer stem cells, the prognostic implications of the expression of these cancer stem cell markers in patient's primary tumors, and the potential of these cancer stem cell markers to serve as therapeutic targets.

EGRI and FOSB gene expressions in cancer stroma are independent prognostic indicators for epithelial ovarian cancer receiving standard therapy

Stromal components interact with cancer cells to promote growth and metastasis. The purpose of this study was to identify genes expressed in stroma, which could provide prognostic information in epithelial ovarian cancer (EOC). Seventy-four patients were included. We performed gene expression profiling and confirmed array data using RT-PCR and immunohistochemistry. By microarray analysis, 52 candidate genes associated with progression free survival (PFS) were identified (P < 0.005). Expression of the early growth response 1 (EGR1) and FBJ murine osteosarcoma viral oncogene homolog B (FOSB) genes was further analyzed. Array data were confirmed by RT-PCR and multivariate analysis demonstrated that both EGR1 and FOSB expression in cancer stroma, and EGR1 expression in cancer are independent prognostic factors in EOC. Immunohistochemically, EGR1 protein is localized in cancer cells and α-smooth muscle actin positive stromal fibroblasts. The EGR1 and FOSB expression in stromal cells and EGR1 expression in cancer cells are prognostic indicators in EOC.

Genomic analysis reveals the molecular heterogeneity of ovarian clear cell carcinomas

PURPOSE

Ovarian clear cell carcinomas (OCCC) are a drug-resistant and aggressive type of epithelial ovarian cancer. We analyzed the molecular genetic profiles of OCCCs to determine whether distinct genomic subgroups of OCCCs exist.

EXPERIMENTAL DESIGN

Fifty pure primary OCCCs were subjected to high-resolution microarray-based comparative genomic hybridization (aCGH). Unsupervised hierarchical clustering using Ward's linkage analysis was performed to identify genomic subgroups of OCCCs. Survival analysis was performed using Kaplan-Meier method and log-rank test. Cox-regression analysis was used to identify independent predictors of outcome. Differentially amplified regions between genomic subgroups of OCCCs were identified using a multi-Fisher's exact test.

RESULTS

Hierarchical cluster analysis revealed two distinct clusters of OCCCs with different clinical outcomes. Patients from cluster-1 had a significantly shorter median progression-free survival (PFS) than those from cluster-2 (11 vs. 65 months, P = 0.009), although estimates for ovarian cancer-specific survival (OCS) did not reach statistical significance (P = 0.065). In multivariate analysis, suboptimal debulking surgery and genomic cluster were independently prognostic for PFS. Recurrently amplified genomic regions with a significantly higher prevalence in cluster-1 than cluster-2 OCCCs were identified and validated. HER2 gene amplification and protein overexpression was observed in 14% of OCCCs, suggesting that this may constitute a potential therapeutic target for a subgroup of these tumors.

CONCLUSIONS

OCCCs constitute a heterogeneous disease at the genomic level despite having similar histological features. The pattern of genomic aberrations in subgroups of OCCCs is of clinical significance. We have identified recurrently amplified regions that may harbor potential therapeutic targets for subgroups of OCCCs.

c-MYC oncoprotein dictates transcriptional profiles of ATP-binding cassette transporter genes in chronic myelogenous leukemia CD34+ hematopoietic progenitor cells

Resistance to chemotherapeutic agents remains one of the major impediments to a successful treatment of chronic myeloid leukemia (CML). Misregulation of the activity of a specific group of ATP-binding cassette transporters (ABC) is responsible for reducing the intracellular concentration of drugs in leukemic cells. Moreover, a consistent body of evidence also suggests that ABC transporters play a role in cancer progression beyond the efflux of cytotoxic drugs. Despite a large number of studies that investigated the function of the ABC transporters, little is known about the transcriptional regulation of the ABC genes. Here, we present data showing that the oncoprotein c-MYC is a direct transcriptional regulator of a large set of ABC transporters in CML. Furthermore, molecular analysis carried out in CD34+ hematopoietic cell precursors of 21 CML patients reveals that the overexpression of ABC transporters driven by c-MYC is a peculiar characteristic of the CD34+ population in CML and was not found either in the population of mononuclear cells from which they had been purified nor in CD34+ cells isolated from healthy donors. Finally, we describe how the methylation state of CpG islands may regulate the access of c-MYC to ABCG2 gene promoter, a well-studied gene associated with multidrug resistance in CML, hence, affecting its expression. Taken together, our findings support a model in which c-MYC-driven transcriptional events, combined with epigenetic mechanisms, direct and regulate the expression of ABC genes with possible implications in tumor malignancy and drug efflux in CML.

Overexpression of cofilin 1 can predict progression-free survival in patients with epithelial ovarian cancer receiving standard therapy

The aim of this study was to examine the relation between cofilin 1 expression and progression-free survival in advanced epithelial ovarian cancer. We performed quantitative reverse transcriptase polymerase chain reaction and immunohistochemical analysis in 78 patients with advanced epithelial ovarian cancer (excluding those with mucinous and clear-cell types). All patients received the standard therapy, including staging laparotomy and adjuvant chemotherapy consisting of carboplatin and paclitaxel. Of 78 samples, RNA from 62 samples was available for reverse transcriptase polymerase chain reaction analysis. We defined cofilin 1 high expression as relative gene expression equal to or higher than the median and low expression as gene expression lower than median. The progression-free survival was longer in cofilin 1 low-expression cases than in high-expression cases (P = .039). Multivariate analysis demonstrated that stage and cofilin 1 expression were significant predictors of progression-free survival. Of the 78 samples, 54 were appropriate for immunohistochemical study. In 35 of those 54 cases, cofilin 1 protein expression was detected. The progression-free survival was longer in cofilin 1 protein-negative cases than in protein-positive cases (P = .042). Expression of cofilin 1 may predict the progression-free survival of patients with advanced epithelial ovarian cancer receiving standard therapy.

Molecular basis of chemosensitivity of platinum pre-treated ovarian cancer to chemotherapy

BACKGROUND

Ovarian cancer shows considerable heterogeneity in its sensitivity to chemotherapy both clinically and in vitro. This study tested the hypothesis that the molecular basis of this difference lies within the known resistance mechanisms inherent to these patients' tumours.

METHODS

The chemosensitivity of a series of 31 ovarian tumours, all previously treated with platinum-based chemotherapy, was assessed using the ATP-based tumour chemosensitivity assay (ATP-TCA) and correlated with resistance gene expression measured by quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) in a TaqMan Array following extraction of mRNA from formalin-fixed paraffin-embedded tissue. The results were standardised against a housekeeping gene (PBGD), and assessed by multiple linear regression.

RESULTS

Predictive multiple linear regression models were derived for four single agents (cisplatin, gemcitabine, topotecan, and treosulfan), and for the combinations of cisplatin+gemcitabine and treosulfan+gemcitabine. Particularly strong correlations were obtained for cisplatin, gemcitabine, topotecan, and treosulfan+gemcitabine. No individual gene expression showed direct correlation with activity in the ATP-TCA. Genes involved in DNA repair and apoptosis were strongly represented, with some drug pumps also involved.

CONCLUSION

The chemosensitivity of ovarian cancer to drugs is related to the expression of genes involved in sensitivity and resistance mechanisms.

Relationship Between ABCF2 Expression and Response to Chemotherapy or Prognosis in Clear Cell Adenocarcinoma of the Ovary

Objectives:

The purpose of this study was to evaluate the association of ABCF2 (adenosine triphosphate-binding cassette superfamily F2) protein expression with response to chemotherapy and prognosis in patients with clear cell adenocarcinoma (CCC) of the ovary.

Methods:

One hundred sixty-five patients with CCC were studied, and cytoplasmic ABCF2 expression was detected by immunohistochemical staining. All patients underwent platinum-based primary chemotherapy followed by primary surgery.

Results:

Adenosine triphosphate-binding cassette superfamily F2 expression was detected in 118 (71.5%) of 165 patients and was not related to age or clinical stage. The response rate to chemotherapy in 38 patients with measurable disease was 47.3% (18/38). The response rate tended to be higher in patients without ABCF2 expression than in those with ABCF2 expression; however, this difference was not significant (66.7% vs 34.8%, P = 0.096). There was no significant difference in overall survival between ABCF2-positive and ABCF2-negative cases (median survival time, 1175 vs 1257 days; P = 0.24).

Conclusions:

Adenosine triphosphate-binding cassette superfamily F2 protein was highly expressed in CCC of the ovary, but expression was not related to age, clinical stage, chemoresponse, or prognosis.

Amplification of GNAS may be an independent, qualitative, and reproducible biomarker to predict progression-free survival in epithelial ovarian cancer

OBJECTIVES

The purpose of this study was to identify genes that predict progression-free survival (PFS) in advanced epithelial ovarian cancer (aEOC) receiving standard therapy.

METHODS

We performed microarray analysis on laser microdissected aEOC cells. All cases received staging laparotomy and adjuvant chemotherapy (carboplatin+paclitaxel) as primary therapy.

RESULTS

Microarray analysis identified 50 genes differentially expressed between tumors of patients with no evidence of disease (NED) or evidence of disease (ED) (p<0.001). Six genes (13%) were located at 8q24, and 9 genes (19.6%), at 20q11-13. The ratio of selected gene set/analyzed gene set in chromosomes 8 and 20 are significantly higher than that in other chromosome regions (6/606 vs. 32/13656, p=0.01) and (12/383 vs. 32/13656, p=1.3 x 10(-)(16)). We speculate that the abnormal chromosomal distribution is due to genomic alteration and that these genes may play an important role in aEOC and choose GNAS (GNAS complex locus, NM_000516) on 20q13 based on the p value and fold change. Genomic PCR of aEOC cells also showed that amplification of GNAS was significantly correlated with unfavorable PFS (p=0.011). Real-time quantitative RT-PCR analysis of independent samples revealed that high mRNA expression levels of the GNAS genes, located at chromosome 20q13, was significantly unfavorable indicators of progression-free survival (PFS). Finally, GNAS amplification was an independent prognostic factor for PFS.

CONCLUSIONS

Our results suggest that GNAS gene amplification may be an independent, qualitative, and reproducible biomarker of PFS in aEOC.

Differential expression of hypoxia-inducible protein 2 among different histological types of epithelial ovarian cancer and in clear cell adenocarcinomas

OBJECTIVES

Epithelial ovarian cancer (EOC) can be classified into 5 major histological types. Among them, clear cell adenocarcinoma (CCC) has a poor response to chemotherapy and poor prognosis compared with other histological types. Previously, we reported that the hypoxia-inducible protein 2 (HIG2) gene might be a new biomarker for CCCs, based on its expression profile. In this study, we generated a polyclonal antiserum to HIG2 to explore the use of HIG2 as a predictive biomarker in EOC. In addition, HIG2 expression was evaluated in uterine endometrial and renal CCCs.

METHODS

Hypoxia-inducible protein 2 expression was analyzed by immunohistochemistry in formalin-fixed surgical samples from 254 EOC, 17 endometrial, and 29 renal CCC patients.

RESULTS

Hypoxia-inducible protein 2 is expressed in 175 of 254 ovarian cancer cases. Cytoplasmic HIG2 expression is significantly more frequent in ovarian CCC (83.1%) than in serous (54.9%, P = 0.0001), mucinous (40%, P = 0.00002), or endometrioid (58.1%, P = 0.003) adenocarcinoma. The chemoresponse rate was higher in 24 ovarian CCC patients with cytoplasmic HIG2 expression than in 6 CCC patients without HIG2 expression (62.5% [15/24] vs 0% [0/6], P = 0.02). In contrast, there was no relationship between nuclear HIG2 expression and chemoresponse. Cytoplasmic and nuclear HIG2 expressions are significantly more frequent in ovarian and uterine than renal CCC (P = 0.04).

CONCLUSIONS

Hypoxia-inducible protein 2 may be used as a marker for early detection of ovarian CCCs or for prediction of response to chemotherapy, but HIG2 expression does not predict survival of patients with CCC.

Direct and coordinate regulation of ATP-binding cassette transporter genes by Myc factors generates specific transcription signatures that significantly affect the chemoresistance phenotype of cancer cells

Increased expression of specific ATP-binding cassette (ABC) transporters is known to mediate the efflux of chemotherapeutic agents from cancer cells. Therefore, establishing how ABC transporter genes are controlled at their transcription level may help provide insight into the role of these multifaceted transporters in the malignant phenotype. We have investigated ABC transporter gene expression in a large neuroblastoma data set of 251 tumor samples. Clustering analysis demonstrated a strong association between differential ABC gene expression patterns in tumor samples and amplification of the MYCN oncogene, suggesting a correlation with MYCN function. Using expression profiling and chromatin immunoprecipitation studies, we show that MYCN oncoprotein coordinately regulates transcription of specific ABC transporter genes, by acting as either an activator or a repressor. Finally, we extend these notions to c-MYC showing that it can also regulate the same set of ABC transporter genes in other tumor cells through similar dynamics. Overall our findings provide insight into MYC-driven molecular mechanisms that contribute to coordinate transcriptional regulation of a large set of ABC transporter genes, thus affecting global drug efflux.

Annexin IV is differentially expressed in clear cell carcinoma of the ovary

OBJECTIVE

To investigate the genes that were differentially expressed between clear cell carcinoma (CCC) and serous carcinoma (SAC) of the ovary with complementary DNA microarray.

METHODS

Complementary DNA microarray was carried out in 8 CCCs and 8 SACs of the ovary. Differentially expressed genes were identified and verified by real-time polymerase chain reaction. The expression of the protein was also verified with immunohistochemistry and Western blot in cells and tissues of ovarian CCC.

RESULTS

Comparison of the gene expression profiling identified 21 genes with more than 2-fold different expression between CCC and SAC of the ovary. The up-regulated and down-regulated genes were 9 and 12, respectively. The verification of Annexin IV in the cell line and tissues was in accordance with the result of the microarray.

CONCLUSIONS

The complementary DNA microarray technique is a feasible way to explore the difference of the gene expression profiling between the 2 types of ovarian carcinoma. The overexpression of Annexin IV may be an ovarian CCC-specific molecular marker.

The impact of complete surgical staging upon survival in early-stage ovarian clear cell carcinoma: a multi-institutional retrospective study

Pure-type clear cell carcinoma (CCC) has been recognized as a distinct subtype of ovarian cancer, showing resistance to conventional platinum-based chemotherapy and resulting in poor prognosis. The aim of the study was to evaluate the effects of complete surgical staging procedures for early-stage CCC patients in a retrospective multi-institutional analysis. During the period 1992 to 2002, a total of 199 patients with pT1 M0 CCC were identified. Survival analysis was estimated by Kaplan-Meier methods, and prognostic factors were evaluated using a Cox regression model. Among pT1 M0 tumors, retroperitoneal lymph node status was negative in 125 cases (pN0, 63%), positive in 10 cases (pN1, 5%), and unknown in 64 cases (pNx, 32%). Progression-free survival of pN1 was significantly worse than that of pN0 (P < 0.05), whereas there was no significant difference between pN1 and pNx. There was no significant difference of overall survival (OS) among the 3 groups. Multivariate analysis revealed that peritoneal cytology status was the only independent prognostic factor for progression-free survival (P = 0.04), but completion of surgical staging procedures was not a prognostic factor. There was no significant prognostic factor for OS. Our study implied that complete surgical staging enabled us to distinguish a high-risk group of recurrence in pT1 M0 CCC; however, the procedure could not improve OS. Although the study was a limited retrospective study, the impact of peritoneal cytology status was more important than complete surgical staging procedure in CCC patients. More effective treatment modality was warranted, especially for CCC cases positive for malignant peritoneal cytology.

Theoretical model of treatment strategies for clear cell carcinoma of the ovary: focus on perspectives

OBJECTIVES

Among epithelial ovarian cancer (EOC), clear cell carcinomas (CCC) differ from the other histologic types with respect to their clinical characteristics, carcinogenesis and prognosis. The aim of this review is to summarize the current knowledge and future perspective on the new therapeutic targets and treatment strategies for CCC.

MATERIALS AND METHODS

The present article reviews the English language literature for preclinical and clinical trials and promising molecular targets on CCC of the ovary, based on the gene expression profiling studies.

RESULTS

Here, we show that (1) the expression of the genes involved in transcription, signaling, cell cycle, adhesion, matrix, proteinase, and detoxification was greatly increased in the CCC carcinogenesis; (2) upregulation of hepatocyte nuclear factor-1beta (HNF-1beta) and Polo-like kinase (PLK)-Early mitotic inhibitor-1 (Emi1) as well as their downstream targets are specifically found in most CCC. The promising molecular targeting approach will emerge in the context of HNF-1beta and PLK-Emi1 biology; and 3) several significant common pathways observed in CCC of the ovary overlap the datasets identified in CCC of the kidney. To improve the outcome in CCC therapy, we must learn various adaptive treatment strategies for renal CCC, although it is not supported by any preliminary clinical data.

CONCLUSION

The inhibitors that target HNF-1beta and PLK-Emi1 and their downstream signaling molecules would be evaluated. In addition, the therapy currently used in renal CCC should be considered as an alternative for the present treatments or an attractive therapeutic option for ovarian CCC. The challenges accompanying the recent advance are described in this review article.

Actinin-4 gene amplification in ovarian cancer: a candidate oncogene associated with poor patient prognosis and tumor chemoresistance

Actinin-4, an isoform of non-muscular alpha-actinin, enhances cell motility by bundling the actin cytoskeleton. We previously reported a prognostic implication of high immunohistochemical expression of actinin-4 protein in ovarian cancers. Chromosomal gain or amplification of the 19q12-q13 region has been reported in ovarian cancer. We hypothesized that the actinin-4 (ACTN4) gene might be a target of the 19q12-q13 amplicon and play an essential role of ovarian cancer progression. In total, 136 advanced-stage ovarian cancers were investigated for the copy number of the ACTN4 gene on chromosome 19q13, using fluorescence in situ hybridization, and the correlation of the ACTN4 copy number with actinin-4 protein immunoreactivity and major clinicopathological factors was investigated. A higher copy number (> or =4 copies) of the ACTN4 gene was detected in 29 (21%) cases and was highly associated with the intensity of actinin-4 immunoreactivity (P<0.0001), a high histological tumor grade (P=0.030), a clear-cell adenocarcinoma histology (P=0.012), resistance to first-line chemotherapies (P=0.028), and poor patient outcome (P=0.0011). Univariate analyses using the Cox regression model showed that a higher ACTN4 gene copy number was able to predict patient outcome more accurately than high actinin-4 immunoreactivity (relative risk: 2.48 vs 1.55). Multivariate analysis showed that a higher copy number of the ACTN4 gene and the degree of residual disease were independent prognostic factors for overall patient survival. The actinin-4 gene may be a target of the 19q amplicon, acting as a candidate oncogene, and serve as a predictor of poor outcome and tumor chemoresistance in patients with advanced-stage ovarian cancers.

Ovarian cancer biomarkers: current options and future promise

As more effective, less toxic cancer drugs reach patients, the need for accurate and reliable cancer diagnostics and prognostics has become widely appreciated. Nowhere is this need more dire than in ovarian cancer; here most women are diagnosed late in disease progression. The ability to sensitively and specifically predict the presence of early disease and its status, stage, and associated therapeutic efficacy has the potential to revolutionize ovarian cancer detection and treatment. This article reviews current ovarian cancer diagnostics and prognostics and potential biomarkers that are being studied and validated. Some of the most recent molecular approaches being used to identify genes and proteins are presented, which may represent the next generation of ovarian cancer diagnostics and prognostics.

Can ABCF2 protein expression predict the prognosis of uterine cancer?

Uterine cervical and endometrial cancers are common malignant solid neoplasms for which there are no useful prognostic markers. In this study, we evaluate the relationship between ATP-binding cassette superfamily F2 (ABCF2) expression and clinical factors including clinical stage, histologic type, grade and prognosis in uterine cervical and endometrial cancer. Two hundred and sixty seven cervical and 103 endometrial cancers were studied. ATP-binding cassette superfamily F2 cytoplasmic expression was detected by immunohistochemical staining and scored as positive or negative. Among cervical cancer cases, 149 (55.8%) expressed ABCF2. The overall survival was longer in ABCF2-negative than ABCF2-positive cases (P=0.0069). Statistically significant prognostic factors for survival were ABCF2 positivity (risk ratio (rr)=1.437), old age (rr=1.550) and advanced stage (rr=2.577). ATP-binding cassette superfamily F2 positivity was an independent prognostic factor by multivariate proportional hazard test (P=0.0002). Among endometrial cancer cases, 72 (69.9%) were cytoplasmic ABCF2 positive. However, there was no significant relationship between ABCF2 expression and age, clinical stage, histologic type, histologic grade, oestrogen receptor status or prognosis. ATP-binding cassette superfamily F2 expression may be a useful prognostic marker in cervical but not endometrial cancer. The role of ABCF2 protein may differ depending on the type of cancer.

Activation of platelet-activating factor receptor and pleiotropic effects on tyrosine phospho-EGFR/Src/FAK/paxillin in ovarian cancer

Among the proinflammatory mediators, platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphorylcholine) is a major primary and secondary messenger involved in intracellular and extracellular communication. Evidence suggests that PAF plays a significant role in oncogenic transformation, tumor growth, angiogenesis, and metastasis. However, PAF, with its receptor (PAFR) and their downstream signaling targets, has not been thoroughly studied in cancer. Here, we characterized the PAFR expression pattern in 4 normal human ovarian surface epithelial (HOSE) cell lines, 13 ovarian cancer cell lines, paraffin blocks (n = 84), and tissue microarrays (n = 230) from patients with ovarian cancer. Overexpression of PAFR was found in most nonmucinous types of ovarian cancer but not in HOSE and mucinous cancer cells. Correspondingly, PAF significantly induced cell proliferation and invasion only in PAFR-positive cells (i.e., OVCA429 and OVCA432), but not in PAFR-negative ovarian cells (HOSE and mucinous RMUG-L). The dependency of cell proliferation and invasion on PAFR was further confirmed using PAFR-specific small interfering RNA gene silencing probes, antibodies against PAFR and PAFR antagonist, ginkgolide B. Using quantitative multiplex phospho-antibody array technology, we found that tyrosine phosphorylation of EGFR/Src/FAK/paxillin was coordinately activated by PAF treatment, which was correlated with the activation of phosphatidylinositol 3-kinase and cyclin D1 as markers for cell proliferation, as well as matrix metalloproteinase 2 and 9 for invasion. Specific tyrosine Src inhibitor (PP2) reversibly blocked PAF-activated cancer cell proliferation and invasion. We suggest that PAFR is an essential upstream target of Src and other signal pathways to control the PAF-mediated cancer progression.

Mechanisms of chemoresistance and poor prognosis in ovarian clear cell carcinoma

Clear cell carcinoma (CCC) accounts for 4% to 12% of epithelial ovarian cancer in Western countries and, for some unknown reasons, it comprises more than 20% of such cancers in Japan. CCC shows unique clinical features such as a high incidence of stage I disease, a large pelvic mass, an increased incidence of vascular thromboembolic complications, and hypercalcemia. It is frequently associated with endometriosis. Compared to serous adenocarcinoma (SAC), CCC is relatively resistant to conventional platinum, or taxane-based chemotherapy which is associated with its poor prognosis. However, the mechanisms underlying CCC's resistance to chemotherapy have not been understood. Although several mechanisms involved in drug resistance exist in CCC, including decreased drug accumulation, increased drug detoxification, and an increased DNA repair activity; however, no particular chemoresistance system has been identified. On the other hand, an in vitro study revealed that low cell proliferation may cause the insensitivity of CCC to cisplatin. The Ki-67 labeling index in CCC tumors was significantly lower than SAC. The Ki-67 labeling index for responders was significantly higher than that for non-responders in both tumor types. A multivariable analysis revealed that Ki-67 labeling index and residual tumor size were independent prognostic factors in CCC. Therefore, lower proliferation of the tumor cells may contribute to their resistance to chemotherapy. However, further investigation into the molecular biology and genetics of CCC is warranted. This review discusses the current state of knowledge of the chemoresistance mechanism in CCC and novel treatment strategies for CCC.

Mapping ATP-binding cassette transporter gene expression profiles in melanocytes and melanoma cells

ATP-binding cassette (ABC) transporters regulate the transport of a variety of physiologic substrates. Moreover, several human ABC proteins are responsible for drug exclusion in compound-treated tumor cells, providing cellular mechanisms for the development of multidrug resistance and, therefore, playing an important role in malignant transformation. As only limited information exists on the role of ABC transporters in melanoma, the aim of the study was to generate a complete expression profile of ABC transporters in this tumor entity. Using a TaqMan low-density array for 47 human ABC transporters, mRNA expression analysis was performed from normal human epidermal melanocytes (NHEM P2 and NHEM P3), nine different cell lines originating from primary melanoma (Mel Ei, Mel Juso, Mel Ho and Mel Wei), and metastases of malignant melanoma (Mel Im, Mel Ju, SK Mel 28, HTZ 19 and HMB2). Cell line-specific expression levels were compared with gene expression in pooled RNA from a variety of other human tissues. High expression levels were detected in pooled tissue RNA as well as in cells of melanocytic origin for ABCA5, ABCB2, ABCB6, ABCD3, ABCD4, ABCF1, ABCF2 and ABCF3, whereas ABCB5 revealed a melanocyte-specific high transcript level. In relation to normal melanocytes, ABCB3, ABCB6, ABCC2, ABCC4, ABCE1 and ABCF2 were significantly increased in melanoma cell lines, whereas ABCA7, ABCA12, ABCB2, ABCB4, ABCB5 and ABCD1 showed lower expression levels. In summary, we present here for the first time an ABC-transporter mRNA expression profile in melanoma in comparison to normal melanocytes. The differentially regulated ABC transporters detected by our approach may be candidate genes involved in melanoma tumorigenesis, progression and therapy resistance and could therefore be of great importance to identify novel options for melanoma therapy.

Progression-free survival and overall survival of patients with clear cell carcinoma of the ovary treated with paclitaxel-carboplatin or irinotecan-cisplatin: retrospective analysis

BACKGROUND

Irinotecan hydrochloride, a topoisomerase I inhibitor, has been preliminarily recognized as an effective agent against clear cell carcinoma of the ovary (CCC), but there are few clinical data. Our aim was to compare progression-free survival (PFS) between patients treated with irinotecan hydrochloride and cisplatin (CPT-P) and those with treated with paclitaxel and carboplatin (TC).

METHODS

One hundred and seventeen patients at International Federation of Gynecology and Obstetrics (FIGO) stages Ic (ascites/malignant washing) - IV were identified by scanning the medical records of ten Japanese hospitals. After complete surgical staging procedures including lymphadenectomy, 35 patients received CPT-P and 82 patients received TC. The PFS and overall survival of the two groups were compared using the Kaplan-Meier method.

RESULTS

There was no significant difference in median age, performance status, FIGO stage, rate of optimal cytoreduction, or follow-up period between the CPT-P and TC groups. Two-year and 5-year PFS was 48% and 40%, respectively, in the TC group and 55% and 55%, respectively, in the CPT-P group (P = 0.31). Multiple regression analysis revealed that only residual tumor was an independent prognostic factor for PFS (P < 0.01).

CONCLUSION

CPT-P showed a potential therapeutic effect, at least no less than that of TC therapy. Although there was no significant survival benefit in the present retrospective analysis, we recommend that the CPT-P regimen be evaluated in a larger, prospective, clinical trial.

Claudin-4 overexpression in epithelial ovarian cancer is associated with hypomethylation and is a potential target for modulation of tight junction barrier function using a C-terminal fragment of Clostridium perfringens enterotoxin

BACKGROUND

Claudin-4, a tight junction (TJ) protein and receptor for the C-terminal fragment of Clostridium perfringens enterotoxin (C-CPE), is overexpressed in epithelial ovarian cancer (EOC). Previous research suggests DNA methylation is a mechanism for claudin-4 overexpression in cancer and that C-CPE acts as an absorption-enhancing agent in claudin-4-expressing cells. We sought to correlate claudin-4 overexpression in EOC with clinical outcomes and TJ barrier function, investigate DNA methylation as a mechanism for overexpression, and evaluate the effect of C-CPE on the TJ.

METHODS

Claudin-4 expression in EOC was quantified and correlated with clinical outcomes. Claudin-4 methylation status was determined, and claudin-4-negative cell lines were treated with a demethylating agent. Electric cell-substrate impedance sensing was used to calculate junctional (paracellular) resistance (Rb) in EOC cells after claudin-4 silencing and after C-CPE treatment.

RESULTS

Claudin-4 overexpression in EOC does not correlate with survival or other clinical endpoints and is associated with hypomethylation. Claudin-4 overexpression correlates with Rb and C-CPE treatment of EOC cells significantly decreased Rb in a dose- and claudin-4-dependent noncytotoxic manner.

CONCLUSIONS

C-CPE treatment of EOC cells leads to altered TJ function. Further research is needed to determine the potential clinical applications of C-CPE in EOC drug delivery strategies.

Whole genome oligonucleotide-based array comparative genomic hybridization analysis identified fibroblast growth factor 1 as a prognostic marker for advanced-stage serous ovarian adenocarcinomas

PURPOSE

To identify markers that can predict overall survival in patients with high-grade advanced stage serous adenocarcinomas.

PATIENTS AND METHODS

Oligonucleotide array comparative genomic hybridization (aCGH) was performed on 42 microdissected high-grade serous ovarian tumor samples. aCGH segments were obtained and a prediction Cox model was built and validated by the standard leave one out analysis. Both DNA and mRNA copy numbers of selected genes located on the candidate aCGH segments were determined by quantitative polymerase chain reaction (qPCR) and quantitative reverse transcriptase PCR (qRT-PCR) analyses. The gene that showed the highest correlation was further validated on an independent set of specimens and was selected for further functional studies.

RESULTS

Two chromosomal regions, 4p16.3 and 5q31-5q35.3, exhibited the strongest correlation with overall survival (P < .01). From the 5q31 region, fibroblast growth factor 1 (FGF-1) was selected for further validation study. FGF-1 mRNA copy number was significantly correlated with DNA copy number and protein expression levels (P = .021 and < .001), and both FGF-1 mRNA and protein levels were significantly associated with overall survival (P = .018 and .042). This association was validated for protein expression on an independent set of 81 samples, significant to P = .006. Further studies showed significant correlation between FGF-1 protein expression and CD31+ staining in the tumor stroma (P = .024). Finally, both cancer cells and endothelial cells treated with exogenous FGF-1 showed a significant increase in cell motility and survival.

CONCLUSION

Amplification of FGF-1 at 5q31 in ovarian cancer tissues leads to increased angiogenesis, and autocrine stimulation of cancer cells, which may result in poorer overall survival in patents with high-grade advanced stage serous ovarian cancer.

Tumor vascular proteins as biomarkers in ovarian cancer

PURPOSE

This study aimed to identify novel ovarian cancer biomarkers and potential therapeutic targets through molecular analysis of tumor vascular cells.

METHODS

Immunohistochemistry-guided laser-capture microdissection and genome-wide transcriptional profiling were used to identify genes that were differentially expressed between vascular cells from human epithelial ovarian cancer and healthy ovaries. Tumor vascular markers (TVMs) were validated through quantitative real-time polymerase chain reaction (qRT-PCR) of immunopurified tumor endothelial cells, in situ hybridization, immunohistochemistry, and Western blot analysis. TVM expression in tumors and noncancerous tissues was assessed by qRT-PCR and was profiled using gene expression data.

RESULTS

We identified a tumor vascular cell profile of ovarian cancer that was distinct from the vascular profile of normal ovary and other tumors. We validated 12 novel ovarian TVMs. These were expressed by immunopurified tumor endothelial cells and localized to tumor vasculature. Select TVMs were found to be specifically expressed in ovarian cancer and were absent in all normal tissues tested, including female reproductive tissues with physiologic angiogenesis. Many ovarian TVMs were expressed by a variety of other solid tumors. Finally, overexpression of any one of three ovarian TVMs by vascular cells was associated with decreased disease-free interval (all P < .005).

CONCLUSION

We have identified for the first time the molecular profile of ovarian tumor vasculature. We demonstrate that TVMs may serve as potential biomarkers and molecular targets for ovarian cancer and a variety of other solid tumors.

Biomarker discovery in epithelial ovarian cancer by genomic approaches

Ovarian cancer is the fifth most common form of cancer in women in the United States. It is a complex disease composed of different histological grades and histological types. Most of epithelial ovarian cancer cases are detected at an advanced stage. Patients usually respond to primary treatment with surgery and chemotherapy. However, the disease usually recurs and is ultimately fatal. So far, a satisfactory screening procedure and regime to treat the recurrence disease are not available. High-throughput genomic analyses have the potential to change the detection and the treatment of ovarian neoplasms. They can help diagnose subtypes of disease and predict patient survival. New diagnostic and prognostic markers for ovarian cancer are emerging. One day, profiling may influence treatment decisions, informing both which patients should receive chemotherapy and what type of chemotherapeutic agents should be employed. As greater numbers of tumor samples are analyzed, the power of these profiling studies will increase, raising the possibility that novel molecular targets and less toxic therapies will be identified. These powerful techniques hold the potential to unravel the genetic origins of ovarian cancer. Hopefully, this will translate into earlier diagnosis and better patient outcome from disease.

Differential expression of ABCF2 protein among different histologic types of epithelial ovarian cancer and in clear cell adenocarcinomas of different organs

Previously, we reported that ABCF2 protein expression is higher in clear cell than serous histotype of ovarian adenocarcinomas and that its expression correlates with chemoresponse in patients with clear cell ovarian cancer. In this study, we examined ABCF2 protein expression in mucinous, endometrioid, and poorly differentiated type of ovarian adenocarcinomas. In addition, ABCF2 expression was evaluated in clear cell adenocarcinomas derived from different organs. A total of 335 epithelial ovarian cancers, 23 clear cell adenocarcinomas of uterine corpus, and 34 clear cell adenocarcinomas of kidney were included in this study. ABCF2 protein expression was determined by immunohistochemistry. The results showed that cytoplasmic ABCF2 expression was significantly higher in clear cell-type ovarian cancer specimens compared with other types (P < .0001). There was a close relationship between nuclear ABCF2 expression levels and age of patients with clear cell ovarian cancer. Multivariate logistic regression model also demonstrated that cytoplasmic ABCF2 expression was associated with clear cell histology (odds ratio, 5.557; 95% confidence interval, 2.694-11.462; P < .0001). In addition, both clear cell adenocarcinomas of the ovary and the uterine corpus showed significantly higher levels of ABCF2 expression, compared with those of the clear cell adenocarcinoma of the kidney (P < .0001). These data suggest that ABCF2 protein may be a candidate marker for clear cell adenocarcinomas of the ovary and the uterine corpus and may be important for the pathogenesis of these diseases.

Enteropathogenic Escherichia coli effector EspF interacts with host protein Abcf2

Enteropathogenic Escherichia coli (EPEC) is a major causative agent of infant diarrhoea in developing countries. The EspF effector protein is injected from EPEC into host cells via a type III secretion system and is involved in the disruption of host intestinal barrier function. In addition, EspF is sorted to mitochondria and has a role in initiating the mitochondrial death pathway. To clarify the manner in which EspF affects host cells, we sought to identify eukaryotic EspF-binding proteins using affinity purification. Abcf2, a protein of unknown function and member of the ABC-transporter family, bound EspF in this assay. An interaction between EspF and Abcf2 was confirmed in a yeast two-hybrid system, by colocalization and by co-immunoprecipitation from EPEC-infected cells. Levels of Abcf2 were decreased in cells infected with EPEC in an EspF dose-dependent manner. Knock-down of Abcf2 expression by RNA interference increased EspF-induced caspase 9 and caspase 3 cleavage. In addition, Abcf2-knocked down cells showed increased caspase 3 cleavage upon treatment with the apoptosis inducing agent staurosporine. These results indicate that EspF induces or facilitates host cell death by targeting and interfering with the putative protective function of Abcf2.

Ovarian clear cell adenocarcinoma: a continuing enigma

Ovarian clear cell adenocarcinomas (OCCAs) account for <5% of all ovarian malignancies. Compared to other epithelial ovarian cancer (EOC) subtypes, when at an advanced stage, they are associated with a poorer prognosis and are relatively resistant to conventional platinum-based chemotherapy. By contrast, early-stage clear cell ovarian cancer carries a relatively good prognosis. Hence, there is a need to improve our understanding of its pathobiology in order to optimise currently available treatments and develop new therapeutic strategies. This review summarises the currently available literature regarding the pathogenesis of OCCA, its molecular genetic features and postulated molecular mechanisms that underlie its chemoresistant phenotype. Marked similarities with clear cell carcinomas of the kidney and endometrium have been noted by some investigators, raising interesting possibilities regarding novel therapeutic approaches. Unfortunately, most studies on OCCA have hitherto been hampered by insufficient sample sizes, leaving many key issues unresolved. It is envisaged that in the future, high-resolution genomic and gene-expression microarray studies incorporating larger sample sizes will lead to the characterisation of the key molecular players in OCCA biology, which may potentially lead to the identification of novel targets for therapeutic development.