Serous Epithelial Ovarian Cancer Cell Research Articles

Suppression of the ABCA1 Cholesterol Transporter Impairs the Growth and Migration of Epithelial Ovarian Cancer.

Simple SummaryEpithelial ovarian cancer (EOC) is the most lethal gynaecological cancer. Over 80% of cases have already spread at diagnosis, and these patients face a five-year survival rate of 35%. EOC cells often spread to the greater omentum, an abdominal fat pad. Here, EOC cells take-up cholesterols. Excessive amounts of cholesterol are lethal; thus, we proposed that the ABCA1 cholesterol transporter exports cholesterol from serous EOC cells to maintain cholesterol balance. Indeed, we found that reducing the level of ABCA1 could suppress serous EOC growth in two-dimensional as well as three-dimensional cell culture and also hindered their migration, a key process required for cancer spread. We also identified drugs that impair EOC cell growth by inhibiting cholesterol export. Our data demonstrate that disrupting the cholesterol balance by targeting ABCA1 may be an effective treatment strategy for EOC patients.Background: Epithelial ovarian cancer (EOC) is the most lethal gynaecological malignancy with over 80% of cases already disseminated at diagnosis and facing a dismal five-year survival rate of 35%. EOC cells often spread to the greater omentum where they take-up cholesterol. Excessive amounts of cholesterol can be cytocidal, suggesting that cholesterol efflux through transporters may be important to maintain homeostasis, and this may explain the observation that high expression of the ATP-binding cassette A1 (ABCA1) cholesterol transporter has been associated with poor outcome in EOC patients. Methods: ABCA1 expression was silenced in EOC cells to investigate the effect of inhibiting cholesterol efflux on EOC biology through growth and migration assays, three-dimensional spheroid culture and cholesterol quantification. Results: ABCA1 suppression significantly reduced the growth, motility and colony formation of EOC cell lines as well as the size of EOC spheroids, whilst stimulating expression of ABCA1 reversed these effects. In serous EOC cells, ABCA1 suppression induced accumulation of cholesterol. Lowering cholesterol levels using methyl-B-cyclodextrin rescued the effect of ABCA1 suppression, restoring EOC growth. Furthermore, we identified FDA-approved agents that induced cholesterol accumulation and elicited cytocidal effects in EOC cells. Conclusions: Our data demonstrate the importance of ABCA1 in maintaining cholesterol balance and malignant properties in EOC cells, highlighting its potential as a therapeutic target for this disease.

ABCC4/MRP4 contributes to the aggressiveness of Myc-associated epithelial ovarian cancer.

Epithelial ovarian cancer (EOC) is a complex disease comprising discrete histological and molecular subtypes, for which survival rates remain unacceptably low. Tailored approaches for this deadly heterogeneous disease are urgently needed. Efflux pumps belonging to the ATP-binding cassette (ABC) family of transporters are known for roles in both drug resistance and cancer biology and are also highly targetable. Here we have investigated the association of ABCC4/MRP4 expression to clinical outcome and its biological function in endometrioid and serous tumors, common histological subtypes of EOC. We found high expression of ABCC4/MRP4, previously shown to be directly regulated by c-Myc/N-Myc, was associated with poor prognosis in endometrioid EOC (P = .001) as well as in a subset of serous EOC with a "high-MYCN" profile (C5/proliferative; P = .019). Transient siRNA-mediated suppression of MRP4 in EOC cells led to reduced growth, migration and invasion, with the effects being most pronounced in endometrioid and C5-like serous cells compared to non-C5 serous EOC cells. Sustained knockdown of MRP4 also sensitized endometrioid cells to MRP4 substrate drugs. Furthermore, suppression of MRP4 decreased the growth of patient-derived EOC cells in vivo. Together, our findings provide the first evidence that MRP4 plays an important role in the biology of Myc-associated ovarian tumors and highlight this transporter as a potential therapeutic target for EOC.

Imiquimod Inhibits Proliferation of Serous Epithelial Ovarian Cancer Cells In Vitro: A Preliminary Study

Imiquimod, known as positive immune response modifier and stimulates local cytokine induction, has been used in therapy of genital warts via increasing local interferon and reducing human papillomavirus production. We aimed to investigate whether imiquimod has any effect on the proliferation of serous epithelial ovarian cancer cells in vitro. The study was designed in two stages. The first stage was designed to evaluate co-culturing of serous epithelial ovarian cancer cells with the drug imiquimod versus cancer cells cultured with no drug. The second stage of the study was initiated with primary ovarian cancer cell culture growth. Imiquimod was applied in increasing concentrations to flasks full of each kind of cells. Also, histomorphometrical evaluation was made using an unbiased counting frame. Treatment of the primary cancer cell cultures with imiquimod in concentrations of 2.5 μg/ml and 5.0 μg/ml did not result in a significant effect on cell proliferation and the cell proliferation continued. Cell proliferation stopped and the cells detached at concentrations of 7.5 μg/ml, especially 10.0 μg/ml, 12.5 μg/ml, and 25.0 μg/ml, within 2–3 days after exposure to the drug. The anti-proliferative effect of imiquimod reached a maximum level at a concentration of 12.5 μg/ml. Imiquimod has a dose-dependent anti-proliferative impact on serous epithelial ovarian cancer cells in vitro.

Abstract NT-111: THE ANTIPROGESTIN/ANTIGLUCOCORTICOID MIFEPRISTONE AND THE HIV PROTEASE INHIBITOR NELFINAVIR CAUSE ENDOPLASMIC RETICULUM STRESS AND POTENTIATE THE TOXICITY OF PROTEASOME INHIBITION IN HIGH-GRADE SEROUS EPITHELIAL OVARIAN CANCER CELLS

Abstract Epithelial ovarian cancer (EOC) is a fatal disease due to late diagnosis and lack of effective long-term treatment(s). Since the introduction of debulking surgery and platinum (Pt)-taxane (Tx) therapy over 30 yrs. ago, there has been no significant breakthrough impacting the overall survival of these patients. Though over 70% of diagnosed women respond to front-line standard of care with remission, the disease hides as microscopic (minimal residual) within the abdominal cavity for about 18-24 months (mo.), recurring thereafter with a phenotype usually not responsive to current chemotherapeutic agents. As patients are left without treatment between remission and recurrence, our research initiative is to develop a consolidation therapy for chronic use after standard of care. In this work we explored whether such consolidation therapy could be developed from two simultaneous strategies: proteasome inhibition and aggravation of the stress of the endoplasmic reticulum (ER). The rationale for this combination therapy is that malignant cells are more susceptible to the toxicity of proteasome inhibition and operate with increased expression of ER stress-related proteins—coined as unfolded protein response (UPR) addiction—allowing cancer cells to survive in a hostile environment of reduced nutrients, acidosis, energy deficiency, and low oxygen tension (hypoxia). We hypothesized that simultaneous ER stress aggravation and blockage of the proteolytic capacity of the proteasome should cause sufficient ER stress to tilt cells to a death fate. We report that antiprogestin/antiglucocorticoid mifepristone (MF) as well as HIV protease inhibitor nelfinavir (NFV) enhanced the stress of the ER in EOC cells of high-grade serous origin (HGSOC), which is the most aggressive subtype of EOC, represents the majority of cases of EOC, and causes 2/3 of all deaths from this disease. We demonstrated, in HGSOC cells, that both MF and NFV cause cell cycle arrest associated with increased expression of cyclin dependent kinase inhibitor p27kip1, while triggering the UPR in a dose-dependent manner assessed by increased subrogate ER stress biomarkers GRP78, ATF4, and CHOP. We also discovered that blocking the ubiquitin proteasome system (UPS) using cytostatic concentrations of the proteasome inhibitor bortezomib (BZ) causes accumulation of poly-ubiquitinated proteins and further activation of the UPR. More importantly, when we combined BZ with either MF or NFV, we observed a potentiation of the action of BZ leading to EOC lethality. These results suggest that targeting the ER stress-associated protein quality control machinery with either an antiprogestin/antiglucocorticoid agent or an HIV protease inhibitor may provide an alternative chronic treatment approach against HGSOC after standard of care. In addition, the data provide the rationale for rapid repurposing to treating HGSOC, of three drugs clinically approved for other uses, as their systemic toxicities have already been assessed. Citation Format: Mahbuba Subeha, Lei Zhang, Alicia Goyeneche, Carlos Telleria. THE ANTIPROGESTIN/ANTIGLUCOCORTICOID MIFEPRISTONE AND THE HIV PROTEASE INHIBITOR NELFINAVIR CAUSE ENDOPLASMIC RETICULUM STRESS AND POTENTIATE THE TOXICITY OF PROTEASOME INHIBITION IN HIGH-GRADE SEROUS EPITHELIAL OVARIAN CANCER CELLS [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr NT-111.

Pharmacological Inhibition of p38 MAPK by SB203580 Increases Resistance to Carboplatin in A2780cp Cells and Promotes Growth in Primary Ovarian Cancer Cells.

Chemoresistance renders current chemotherapy regimens ineffective against advanced epithelial ovarian cancer (EOC). Carboplatin (the first-line chemotherapeutic agent to treat EOC) induces cell death by regulating multiple signaling pathways. The objective of this study is to identify the signaling pathways that contribute to carboplatin resistance in EOC. To this end, we performed a proteome profiler human phospho-kinase array experiment and compared the phosphorylation profiles between the cisplatin-sensitive A2780s versus its derivative cisplatin-resistant A2780cp cells. The phospho-kinase array revealed that A2780s and A2780cp cells displayed different profiles in basal and carboplatin-induced phosphorylation. Phosphorylation of p38 MAPK was increased by carboplatin more markedly in A2780s cells compared to A2780cp cells. Inhibition of p38 MAPK activity by its specific inhibitor SB203580 increased resistance to carboplatin in A2780cp cells, but not in A2780s cells or in ascites-derived high-grade serous EOC cells. Interestingly, SB203580 increased the number of viable cells in the primary EOC cells, which was concomitant with an increase in survivin expression. In conclusion, inhibition of p38 MAPK by SB203580 increases resistance to carboplatin in A2780cp cells and the number of viable cells in the primary EOC cells, suggesting that pharmacological inhibition of p38 MAPK might not be an effective therapeutic strategy for EOC.

Cumulative defects in DNA repair pathways drive the PARP inhibitor response in high-grade serous epithelial ovarian cancer cell lines.

PARP inhibitors (PARPi), such as Olaparib, have shown promising results in high-grade serous (HGS) epithelial ovarian cancer (EOC) treatment. PARPi sensitivity has been mainly associated with homologous recombination (HR) deficiency, but clinical trials have shown that predicting actual patient response is complex. Here, we investigated gene expression microarray, HR functionality and Olaparib sensitivity of 18 different HGS EOC cell lines and demonstrate that PARPi sensitivity is not only associated with HR defects. Gene target validation show that down regulation of genes in the nucleotide excision repair (NER) and mismatch repair (MMR) pathways (ERCC8 and MLH1, respectively) increases PARPi response. The highest sensitivity was observed when genes in both the HR and either NER or MMR pathways were concomitantly down regulated. Using clinical samples, patients with these concurrent down regulations could be identified. Based on these results, a novel model to predict PARPi sensitivity is herein proposed. This model implies that the extreme responders identified in clinical trials have deficiencies in HR and either NER or MMR.

Upregulated CDK16 Expression in Serous Epithelial Ovarian Cancer Cells.

BackgroundAs CDK-16 has been shown to be upregulated in several transformed cancer lines, we hypothesized that the cyclin-dependent kinase 16 (CDK-16) may be upregulated in serous epithelial ovarian cancer (EOC) cells. Therefore, we comparatively examined the mRNA and protein expression of CDK-16 in samples resected from serous EOC patients and normal controls.Material/MethodsTissue samples were collected from 70 serous EOC patients and 40 normal controls. Quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) was conducted to assess mRNA expression. CDK-16 protein expression was assessed by semi-quantitative immunohistochemical staining. Differences in mRNA and protein expression between serous EOC cells and normal tissue cells were tested with the Kruskal-Wallis test and analysis of variance (ANOVA).ResultsBoth CDK-16 mRNA and protein expression were significantly higher in serous EOC tumor cells as compared to normal control ovarian cells (p<0.01). Although there was no significant correlation between CDK-16 mRNA expression and serous EOC stage (p=0.0794), there was a significant correlation between CDK-16 mRNA expression and serous EOC grade (p<0.0001). Moreover, there were significant correlations between CDK-16 protein expression and serous EOC stage (p<0.0001) and grade (p<0.0001).ConclusionsCDK-16 upregulation in serous EOC cells may represent a negative feedback loop to promote ovarian cell differentiation in malignantly-transformed serous EOC cells. Further in-depth investigation on CDK-16’s role in serous EOC is needed.

Novel high-grade serous epithelial ovarian cancer cell lines that reflect the molecular diversity of both the sporadic and hereditary disease

Few cell line models of epithelial ovarian cancer (EOC) have been developed for the high-grade serous (HGS) subtype, which is the most common and lethal form of gynaecological cancer. Here we describe the establishment of six new EOC cell lines spontaneously derived from HGS tumors (TOV2978G, TOV3041G and TOV3291G) or ascites (OV866(2), OV4453 and OV4485). Exome sequencing revealed somatic TP53 mutations in five of the cell lines. One cell line has a novel BRCA1 splice-site mutation, and another, a recurrent BRCA2 nonsense mutation, both of germline origin. The novel BRCA1 mutation induced abnormal splicing, mRNA instability, resulting in the absence of BRCA1 protein. None of the cell lines harbor mutations in KRAS or BRAF, which are characteristic of other EOC subtypes. SNP arrays showed that all of the cell lines exhibited structural chromosomal abnormalities, copy number alterations and regions of loss of heterozygosity, consistent with those described for HGS. Four cell lines were able to produce 3D-spheroids, two exhibited anchorage-independent growth, and three (including the BRCA1 and BRCA2 mutated cell lines) formed tumors in SCID mice. These novel HGS EOC cell lines and their detailed characterization provide new research tools for investigating the most common and lethal form of EOC.

MicroRNA-200c and microRNA-31 regulate proliferation, colony formation, migration and invasion in serous ovarian cancer.

BackgroundSerous epithelial ovarian cancer (SEOC) is a highly metastatic disease and its progression has been implicated with microRNAs. This study aimed to identify the differentially expressed microRNAs in Malaysian patients with SEOC and examine the microRNAs functional roles in SEOC cells.MethodsTwenty-two SEOC and twenty-two normal samples were subjected to miRNA expression profiling using the locked nucleic acid (LNA) quantitative real-time PCR (qPCR). The localization of miR-200c was determined via LNA in situ hybridization (ISH). Functional analysis of miR-200c and miR-31 on cell proliferation, migration and invasion and clonogenic cell survival were assessed in vitro. The putative target genes of the two miRNAs were predicted by miRWalk program and expression of the target genes in SEOC cell lines was validated.ResultsThe miRNA expression profiling revealed thirty-eight significantly dysregulated miRNAs in SEOC compared to normal ovarian tissues. Of these, eighteen were up-regulated whilst twenty miRNAs were down-regulated. We observed chromogenic miR-200c-ISH signal predominantly in the cytoplasmic compartment of both epithelial and inflammatory cancer cells. Re-expression of miR-200c significantly increased the cell proliferation and colony formation but reduced the migration and invasion of SEOC cells. In addition, miR-200c expression was inversely proportionate with the expression of deleted in liver cancer-1 (DLC-1) gene. Over-expression of miR-31 in SEOC cells resulted in decreased cell proliferation, clonogenic potential, cell migration and invasion. Meanwhile, miR-31 gain-of-function led to the down-regulation of AF4/FMR2 family member 1 (AFF1) gene.ConclusionsThese data suggested that miR-200c and miR-31 may play roles in the SEOC metastasis biology and could be considered as promising targets for therapeutic purposes.Electronic supplementary materialThe online version of this article (doi:10.1186/s13048-015-0186-7) contains supplementary material, which is available to authorized users.

Kindlin-2 inhibits serous epithelial ovarian cancer peritoneal dissemination and predicts patient outcomes

Kindlin-2 has been known to promote most cancer progression through regulation of multiple signaling pathways. However, a novel tumor suppressive role of Kindlin-2 was identified in serous epithelial ovarian cancer progression, which sharply contrasts to the tumor promoting roles for Kindlin-2 in most other cancers. While we demonstrated that Kindlin-2 was highly expressed in control tissues, a drastic low expression of Kindlin-2 was found in the tumor tissues of serous epithelial ovarian cancer, especially in the high-grade serous epithelial ovarian cancer. Importantly, Kindlin-2 inhibited serous epithelial ovarian cancer cell peritoneal dissemination in a mouse model. For clinical relevance, low Kindlin-2 expression correlated with higher tumor grade and older patients. Intriguingly, decreased Kindlin-2 expression predicts poor overall and progression-free survivals in serous epithelial ovarian cancer patients. Mechanistically, Kindlin-2 induced a mesenchymal to epithelial transition in serous epithelial ovarian cancer cells, at least in part, by up-regulation of estrogen receptor α which was recruited to the promoter of E-cadherin and thereby enhanced the transcription of E-cadherin. Collectively, we concluded that inadequate Kindlin-2 is an independent risk factor for serous epithelial ovarian cancer patients.

A Novel Pathway that Links Caveolin-1 Down-Regulation to BRCA1 Dysfunction in Serous Epithelial Ovarian Cancer Cells.

Ovarian cancer is the second most common gynecological cancer and the five-year survival rate is only about 40%. High-grade serous carcinoma is the pre-dominant histotype associated with hereditary ovarian cancer and women with inherited mutations in BRCA1 have a lifetime risk of 40-60%. BRCA1 and its isoform BRCA1a are multifunctional proteins that are the most evolutionary conserved of all the other splice variants. Our group has previously reported that BRCA1/1a proteins, unlike K109R and C61G mutants, suppress growth of ovarian cancer cells by tethering Ubc9. In this study we found wild type BRCA1/1a proteins to induce expression of caveolin-1, a tumor suppressor in BRCA1-mutant serous epithelial ovarian cancer (SEOC) cells by immunofluorescence analysis. The K109R and C61G disease associated mutant BRCA1 proteins that do not bind Ubc9 were not as efficient in up-regulation of caveolin-1 expression in SEOC cells. Additionally, immunofluorescence analysis showed BRCA1/1a proteins to induce redistribution of Caveolin-1 from cytoplasm and nucleus to the cell membrane. This is the first study demonstrating the physiological link between loss of Ubc9 binding, loss of growth suppression and loss of Caveolin-1 induction of disease-associated mutant BRCA1 proteins in SEOC cells. Decreased Caveolin-1 expression combined with elevated Ubc9 expression can in the future be used as an early biomarker for BRCA1 mutant SEOC.

Wnt5a Influences Viability, Migration, Adhesion, Colony Formation, Eand N-Cadherin Expression of Human Ovarian Cancer Cell Line SKOV-3

Epithelial ovarian cancer (EOC) cells express Wnt5a, but its role in ovarian cancer progression is poorly defined. The aims of the present study were two-fold: 1) to determine the Wnt5a role in viability, apoptosis, migration, colony formation and adhesion of human serous epithelial ovarian cancer cell line SKOV-3, and 2) to assess the relationship of Wnt5a with Eand N-cadherin in highand low-grade human serous ovarian cancer specimens. Wnt5a over-expression led to 29% increased serum-independent cell viability (P &lt; 0.05) and 35% decreased caspase-3 activity (P &lt; 0.01) compared to SKOV-3 cells. There was 96% (P &lt; 0.001) increased cell motility in Wnt5a-transfected SKOV-3 (SKOV-3/Wnt5a) cells compared to SKOV-3, which was abrogated in the presence of JNK inhibitor. In addition, there was about 42% increased cell adhesion to Matrigel compared to SKOV-3 cells (P &lt; 0.001). Colony-forming assay showed a 4.4-fold increased colony formation in SKOV-3/Wnt5a cells compared to SKOV-3 cells (P &lt; 0.001). Eand N-cadherin levels were reduced by 49 % and 67 % in SKOV-3/Wnt5a cells compared to mock cells, respectively. Wnt5a and E-cadherin immunoexpression was significantly (P &lt; 0.001) different in low-grade serous ovarian cancer (LGSC) and high-grade serous ovarian cancer (HGSC). In HGSC specimens, strong immunoexpression of Wnt5a was detected compared to LGSC. However, E-cadherin showed moderate immunostaining (84 %) in HGSC, whereas 100 % of LGSC specimens showed strong immunoexpression. In both groups no N-cadherin immunoexpression was detected. Moreover, Wnt5a showed a positive relationship with E-cadherin in the LGSC group (r = 0.661, P = 0.027). These results may support important roles for Wnt5a in EOC progression.

Empirical chemosensitivity testing in a spheroid model of ovarian cancer using a microfluidics-based multiplex platform

The use of biomarkers to infer drug response in patients is being actively pursued, yet significant challenges with this approach, including the complicated interconnection of pathways, have limited its application. Direct empirical testing of tumor sensitivity would arguably provide a more reliable predictive value, although it has garnered little attention largely due to the technical difficulties associated with this approach. We hypothesize that the application of recently developed microtechnologies, coupled to more complex 3-dimensional cell cultures, could provide a model to address some of these issues. As a proof of concept, we developed a microfluidic device where spheroids of the serous epithelial ovarian cancer cell line TOV112D are entrapped and assayed for their chemoresponse to carboplatin and paclitaxel, two therapeutic agents routinely used for the treatment of ovarian cancer. In order to index the chemoresponse, we analyzed the spatiotemporal evolution of the mortality fraction, as judged by vital dyes and confocal microscopy, within spheroids subjected to different drug concentrations and treatment durations inside the microfluidic device. To reflect microenvironment effects, we tested the effect of exogenous extracellular matrix and serum supplementation during spheroid formation on their chemotherapeutic response. Spheroids displayed augmented chemoresistance in comparison to monolayer culturing. This resistance was further increased by the simultaneous presence of both extracellular matrix and high serum concentration during spheroid formation. Following exposure to chemotherapeutics, cell death profiles were not uniform throughout the spheroid. The highest cell death fraction was found at the center of the spheroid and the lowest at the periphery. Collectively, the results demonstrate the validity of the approach, and provide the basis for further investigation of chemotherapeutic responses in ovarian cancer using microfluidics technology. In the future, such microdevices could provide the framework to assay drug sensitivity in a timeframe suitable for clinical decision making.

Elevated levels of circulating microRNA-200 family members correlate with serous epithelial ovarian cancer

BackgroundThere is a critical need for improved diagnostic markers for high grade serous epithelial ovarian cancer (SEOC). MicroRNAs are stable in the circulation and may have utility as biomarkers of malignancy. We investigated whether levels of serum microRNA could discriminate women with high-grade SEOC from age matched healthy volunteers.MethodsTo identify microRNA of interest, microRNA expression profiling was performed on 4 SEOC cell lines and normal human ovarian surface epithelial cells. Total RNA was extracted from 500 μL aliquots of serum collected from patients with SEOC (n = 28) and age-matched healthy donors (n = 28). Serum microRNA levels were assessed by quantitative RT-PCR following preamplification.ResultsmicroRNA (miR)-182, miR-200a, miR-200b and miR-200c were highly overexpressed in the SEOC cell lines relative to normal human ovarian surface epithelial cells and were assessed in RNA extracted from serum as candidate biomarkers. miR-103, miR-92a and miR -638 had relatively invariant expression across all ovarian cell lines, and with small-nucleolar C/D box 48 (RNU48) were assessed in RNA extracted from serum as candidate endogenous normalizers. No correlation between serum levels and age were observed (age range 30-79 years) for any of these microRNA or RNU48. Individually, miR-200a, miR-200b and miR-200c normalized to serum volume and miR-103 were significantly higher in serum of the SEOC cohort (P < 0.05; 0.05; 0.0005 respectively) and in combination, miR-200b + miR-200c normalized to serum volume and miR-103 was the best predictive classifier of SEOC (ROC-AUC = 0.784). This predictive model (miR-200b + miR-200c) was further confirmed by leave one out cross validation (AUC = 0.784).ConclusionsWe identified serum microRNAs able to discriminate patients with high grade SEOC from age-matched healthy controls. The addition of these microRNAs to current testing regimes may improve diagnosis for women with SEOC.

Abstract 4962: Assessing serum miRNA as putative biomarkers for serous epithelial ovarian cancer

Abstract Serous epithelial ovarian cancer (EOC) is the most lethal gynecological malignancy; due in part to vague and non-specific symptoms resulting in delayed diagnosis. The biomarker in routine clinical use for EOC is CA-125, with the OVA1 test (Quest Diagnostics) recently available to aid in predicting the likelihood that an ovarian mass is malignant. Current diagnostic tests have limitations which may be improved by expansion of biomarker panels. MicroRNAs (miRNAs) are a class of small non-coding RNA molecules that regulate important cellular processes. They exhibit distinct expression profiles in cancers and have recently been discovered in serum and other body fluids. Tumor miRNAs may be shed into the circulation, raising the possibility of their use as serum biomarkers for the detection of EOC. Exiqon LNA miRNA microarrays were performed using RNA from cell line models of serous EOC. Over-expressed miRNAs were selected as candidates for assessment in serum. These were measured in RNA extracted from serum of patients with serous EOC (n=30) and healthy age-matched volunteers (n=30) by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). As there are currently no routine methods for the normalization of miRNA in serum, a group of highly and uniformly expressed miRNAs with no reported involvement in cancer was selected for assessment as endogenous controls. Five miRNAs, miR-182, miR-96 and miR-200a, miR-200b and miR-200c were identified as highly expressed in a panel of serous EOC cell lines consistent with previous reports, and therefore selected for investigation as putative serous EOC biomarkers. In addition, miR-92a, miR-103, miR-638 and RNU48 were selected as candidate endogenous controls given that they were consistently expressed at high levels in the cell line panel. qRT-PCR data will be presented on the expression of these 8 candidate miRNAs and RNU48 either with or without pre-amplification of target sequence. In conclusion, miR-92a, miR-103 and miR-638 were observed to show little variation between patients and healthy volunteer serum. These results identify the potential for these miRNAs to be used as endogenous controls for the expression of miRNA in serum. Reliable detection of specific miRNAs in serum from women with serous EOC may improve the detection of this malignancy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4962. doi:10.1158/1538-7445.AM2011-4962

Characterization of three new serous epithelial ovarian cancer cell lines

BackgroundCell lines constitute a powerful model to study cancer, and here we describe three new epithelial ovarian cancer (EOC) cell lines derived from poorly differentiated serous solid tumors (TOV-1946, and TOV-2223G), as well as the matched ascites for one case (OV-1946).MethodsIn addition to growth parameters, the cell lines were characterized for anchorage independent growth, migration and invasion potential, ability to form spheroids and xenografts in SCID mice.ResultsWhile all cell lines were capable of anchorage independent growth, only the TOV-1946 and OV-1946 cell lines were able to form spheroid and produce tumors. Profiling of keratins, p53 and Her2 protein expression was assessed by immunohistochemistry and western blot analyses. Somatic TP53 mutations were found in all cell lines, with TOV-1946 and OV-1946 harboring the same mutation, and none harbored the commonly observed somatic mutations in BRAF, KRAS or germline BRCA1/2 mutations found to recur in the French Canadian population. Conventional cytogenetics and spectral karyotype (SKY) analyses revealed complex karyotypes often observed in ovarian disease.ConclusionThis is the first report of the establishment of matched EOC cell lines derived from both solid tumor and ascites of the same patient.

Gene expression patterns of chemoresistant and chemosensitive serous epithelial ovarian tumors with possible predictive value in response to initial chemotherapy

Chemotherapy (CT) resistance in ovarian cancer is broad and encompasses diverse, unrelated drugs, suggesting more than one mechanism of resistance. We aimed to analyze the gene expression patterns in primary serous epithelial ovarian cancer (EOC) samples displaying different responses to first-line CT in an attempt to identify specific molecular signatures associated with response to CT. Initially, the expression profiles of 15 chemoresistant serous EOC tumors [time to recurrence (TTR) </=6 months] and 10 chemosensitive serous EOC tumors (TTR > or =30 months) were independently analyzed which allowed the identification of specific sets of differentially expressed genes that might be functionally implicated in the evolution of the chemoresistant or the chemosensitive phenotype. Our data suggest that the intrinsic chemoresistance in serous EOC cells may be attributed to the combined action of different molecular mechanisms and factors linked with drug influx and efflux and cell proliferation, as possible implications of other molecular events including altered metabolism, apoptosis and inflammation cannot be excluded. Next, gene expression comparison using hierarchical clustering clearly distinguished chemosensitive and chemoresistant tumors from the 25 serous EOC samples (training set), and consecutive class prediction analysis was used to develop a 43-gene classifier that was further validated in an independent cohort of 15 serous EOC patients and 2 patients with other ovarian cancer histotypes (test set). The 43-gene predictor set properly classified serous EOC patients at high risk for early (< or =22 months) versus late (>22 months) relapse after initial CT. Thus, gene expression array technology can effectively classify serous EOC tumors according to CT response. The proposed 43-gene model needs further validation.