From gene profiling to diagnostic markers: IL-18 and FGF-2 complement CA125 as serum-based markers in epithelial ovarian cancer

Quantification of putative ovarian cancer serum protein biomarkers using a multiplexed targeted mass spectrometry assay

BACKGROUND

Ovarian cancer is the most lethal gynecologic malignancy in women, and high-grade serous ovarian cancer (HGSOC) is the most common subtype. Currently, no clinical test has been approved by the FDA to screen the general population for ovarian cancer. This underscores the critical need for the development of a robust methodology combined with novel technology to detect diagnostic biomarkers for HGSOC in the sera of women. Targeted mass spectrometry (MS) can be used to identify and quantify specific peptides/proteins in complex biological samples with high accuracy, sensitivity, and reproducibility. In this study, we sought to develop and conduct analytical validation of a multiplexed Tier 2 targeted MS parallel reaction monitoring (PRM) assay for the relative quantification of 23 putative ovarian cancer protein biomarkers in sera.

METHODS

To develop a PRM method for our target peptides in sera, we followed nationally recognized consensus guidelines for validating fit-for-purpose Tier 2 targeted MS assays. The endogenous target peptide concentrations were calculated using the calibration curves in serum for each target peptide. Receiver operating characteristic (ROC) curves were analyzed to evaluate the diagnostic performance of the biomarker candidates.

RESULTS

We describe an effort to develop and analytically validate a multiplexed Tier 2 targeted PRM MS assay to quantify candidate ovarian cancer protein biomarkers in sera. Among the 64 peptides corresponding to 23 proteins in our PRM assay, 24 peptides corresponding to 16 proteins passed the assay validation acceptability criteria. A total of 6 of these peptides from insulin-like growth factor-binding protein 2 (IBP2), sex hormone-binding globulin (SHBG), and TIMP metalloproteinase inhibitor 1 (TIMP1) were quantified in sera from a cohort of 69 patients with early-stage HGSOC, late-stage HGSOC, benign ovarian conditions, and healthy (non-cancer) controls. Confirming the results from previously published studies using orthogonal analytical approaches, IBP2 was identified as a diagnostic biomarker candidate based on its significantly increased abundance in the late-stage HGSOC patient sera compared to the healthy controls and patients with benign ovarian conditions.

CONCLUSIONS

A multiplexed targeted PRM MS assay was applied to detect candidate diagnostic biomarkers in HGSOC sera. To evaluate the clinical utility of the IBP2 PRM assay for HGSOC detection, further studies need to be performed using a larger patient cohort.

Humanized disulfide-stabilized diabody against fibroblast growth factor-2 inhibits PD-L1 expression and epithelial-mesenchymal transition in hepatoma cells through STAT3

Fibroblast growth factor 2 (FGF2) plays an important role in tumor angiogenesis. Humanized disulfide-stable double-chain antibody against fibroblast growth factor-2 (anti-FGF2 ds-Diabody) is a small molecule antibody with good tissue permeability and low immunogenicity, which has potential in tumor-targeted therapy. This study intended to investigate the effect of anti-FGF2 ds-Diabody on the migration and expression of programmed death-ligand1 (PD-L1) in hepatocellular carcinoma (HCC) cells. The anti-FGF2 ds-Diabody was expressed under methanol induction and purified with Ni2+ -affinity chromatography. Anti-FGF2 ds-Diabody significantly inhibited cell viability and proliferation in SK-Hep1 and HepG2 cells as confirmed by CCK-8 assays and colony formation assays. Western blot assays indicated that the proliferation of SK-Hep1 and HepG2 cells was inhibited by anti-FGF2 ds-Diabody through inhibiting the phosphorylation activation of AKT and MAPK. The results of transwell and western blot assays showed that the migration and invasion of SK-Hep1 and HepG2 cells were suppressed by anti-FGF2 ds-Diabody by affecting the epithelial-mesenchymal transition (EMT) process. Meanwhile, anti-FGF2 ds-Diabody inhibited the expression of PD-L1, and STAT3 participated in this process. Analysis of RT-PCR and Western blot suggested that fibroblast growth factor receptor 4 inhibitor 1 (FGFR4-IN-1) suppressed the expression of PD-L1, while STAT3 overexpression reversed this inhibitory effect. In addition, overexpression of STAT3 promoted migration and invasion and restored the suppressive effect of anti-FGF2 ds-Diabody on EMT. In conclusion, anti-FGF2 ds-Diabody could inhibit the expression of PD-L1 and EMT of hepatoma cells through FGF2/FGFR4/STAT3 axis. These results suggested that anti-FGF2 ds-Diabody has potential clinical application in inhibiting metastasis and immune escape of hepatocellular carcinoma.

Antiproliferative Ruthenium Complexes Containing Curcuminoid Ligands Tested In Vitro on Human Ovarian Tumor Cell Line A2780, towards Their Capability to Modulate the NF-κBTranscription Factor, FGF-2 Growth Factor, and MMP-9 Pathway

So far, the polyphenolic components of turmeric have shown a significant pharmacological preventative activity for a wide spectrum of diseases, including oncological disorders. This type of natural product could be of great interest for the inhibition of cancer cell proliferation, displaying less side effects in comparison to classical chemotherapeutics. The poor bioavailability and quick metabolism of such natural compounds require new investigative methods to improve their stability in the organisms. A synthetic approach to increase the efficiency of curcuminoids is to coordinate them to metals through the beta-dicarbonyl moiety. We report the synthesis and the biological attempts on human ovarian carcinoma A2780 of ruthenium(II) complexes 1–4, containing curcuminoid ligands. The cytotoxicity of complexes 1–4 proves their antiproliferative capability, and a correlation between the IC50 values and NF-κB transcription factor, FGF-2, and MMP-9 levels was figured out through the principal component analysis (PCA).

Nuclear action of FGF members in endocrine-related tissues and cancer: Interplay with steroid receptor pathways

Dysregulation of the fibroblast growth factors/fibroblast growth factor receptor (FGF/FGFR) pathway has been implicated in a wide range of human disorders and several members have been localized in the nuclear compartment. Hormone-activated steroid receptors or ligand independent activated receptors form nuclear complexes that activate gene transcription. This review aims to highlight the interplay between the steroid receptor and the FGF/FGFR pathways and focuses on the current knowledge on nuclear action of FGF members in endocrine-related tissues and cancer. The nuclear trafficking and targets of FGF/FGFR members and the available evidence on the interplay with steroid hormones and receptors is described. Finally, the data on aberrant FGF/FGFR signaling is summarized and the nuclear action of FGF members on endocrine resistant breast cancer is highlighted. Identifying the mechanisms underlying FGF-induced endocrine resistance will be important to understand how to efficiently target endocrine-related diseases and even enhance or restore endocrine sensitivity in hormone receptor positive tumors.

Antitumor effect of a short peptide on p53-null SKOV3 ovarian cancer cells

Fibroblast growth factor-2 (FGF2) is a protein ligand, which exerts essential roles in development, angiogenesis, and tumor progression via activation of the downstream signaling cascades. Accumulating evidence has demonstrated that FGF2 is involved in the progression of ovarian cancer, providing a novel potential target for ovarian cancer therapy. In this study, we showed that FGF2 is significantly increased in ovarian tumors, and is negatively associated with the overall survival of ovarian cancer by database analysis. A short peptide obtained from a heptapeptide phage display library suppressed FGF2-induced proliferation, migration, and invasion of the p53-null epithelial ovarian cancer (EOC) cells. Further investigations revealed that the short peptide antagonized the effects of FGF2 on G0/G1 to S cell phase promotion, cyclin D1 expression, and MAPK and Akt signaling activation, which might contribute to the mechanism underlying the inhibitory effects of the short peptide on the aggressive phenotype of the ovarian cancer cells triggered by FGF2. Moreover, the short peptide might have the potentials of reversing FGF2-induced resistance to the doxorubicin via downregulation of the antiapoptotic proteins and counteracting of the antiapoptotic effects of FGF2 on p53-null EOC cells. Taken together, the short peptide targeting FGF2 may provide a novel strategy for improving the therapeutic efficiency in a subset of EOC.

Osteopontin, Macrophage Migration Inhibitory Factor and Anti-Interleukin-8 Autoantibodies Complement CA125 for Detection of Early Stage Ovarian Cancer

Early detection of ovarian cancer promises to reduce mortality. While serum CA125 can detect more than 60% of patients with early stage (I–II) disease, greater sensitivity might be observed with a panel of biomarkers. Ten protein antigens and 12 autoantibody biomarkers were measured in sera from 76 patients with early stage (I–II), 44 patients with late stage (III–IV) ovarian cancer and 200 healthy participants in the normal risk ovarian cancer screening study. A four-biomarker panel (CA125, osteopontin (OPN), macrophage inhibitory factor (MIF), and anti-IL-8 autoantibodies) detected 82% of early stage cancers compared to 65% with CA125 alone. In early stage subjects the area under the receiver operating characteristic curve (AUC) for the panel (0.985) was significantly greater (p < 0.001) than the AUC for CA125 alone (0.885). Assaying an independent validation set of sera from 71 early stage ovarian cancer patients, 45 late stage patients and 131 healthy women, AUC in early stage disease was improved from 0.947 with CA125 alone to 0.974 with the four-biomarker panel (p = 0.015). Consequently, OPN, MIF and IL-8 autoantibodies can be used in combination with CA125 to distinguish ovarian cancer patients from healthy controls with high sensitivity. Osteopontin appears to be a robust biomarker that deserves further evaluation in combination with CA125.

A COEUR cohort study of SATB2 expression and its prognostic value in ovarian endometrioid carcinoma

The aim of this study was to describe the expression of special AT-rich sequence-binding protein 2 (SATB2) in ovarian endometrioid carcinoma (EC). SATB2 is a nuclear matrix-associated transcription factor that is associated with abnormal expression in certain cancers but has not been reported for ovarian carcinoma. SATB2 mRNA and protein expression was first assessed in a pilot cohort of 26 samples by Affymetrix microarray and by routine immunohistochemistry on a small tissue microarray. A large multicenter validation cohort representing the well-characterized cases of 235 ovarian EC from the Canadian Ovarian Experimental Unified Resource (COEUR) was then used to validate this result and to assess the prognostic impact of SATB2 expression. SATB2 staining was scored as negative, weak, moderate, and strong intensity, and by percentage of stained cells. No SATB2 expression was observed in clear cell carcinomas but 10% (n = 3) of the ECs in the pilot cohort showed SATB2 expression. In the validation cohort, strong expression was observed in 11% of ECs, while weak or moderate expression levels were detected in 12% of cases. Evaluation of SATB2 expression with clinicopathological parameters revealed an association with patient age and Federation International of Gynecology and Obstetrics grade but not with disease stage or postoperative residual disease. Any expression of SATB2, independent of intensity, was also associated with longer survival and improved progression-free survival with hazard ratio (HR) = 0.14 (95% CI 0.03-0.56) and HR = 0.16 (95% CI 0.02-1.24) respectively. A greater beneficial effect was observed in patients with stage III/IV disease compared to patients with stage I/II disease. Furthermore, direct comparison of SATB2 with other reported prognostic biomarkers such as progesterone receptor, CDX2 and β-catenin within this cohort showed that SATB2 had the strongest association with survival. Given the current lack of accurate prognostic factors for these patients, SATB2 has promising clinical utility and warrants further study.

Overexpression of low density lipoprotein receptor-related protein 1 (LRP1) is associated with worsened prognosis and decreased cancer immunity in clear-cell renal cell carcinoma

AIM

Clear-cell renal cell carcinoma (ccRCC) is characterized with underlying genetic disorders and the role of low density lipoprotein receptor-related protein 1 (LRP1) in ccRCC is unknown.

METHOD

An in silico exploratory analysis using multiple public genetic datasets was used to establish association between LRP1 expression and clinicopathological parameters. Associations of interest were validated using 155 ccRCC samples using immunohistochemistry.

RESULTS

LRP1 was overexpressed in tumor compared with normal kidney tissue. Increased LRP1 expression in ccRCC was associated with advanced stage, grade and worsened overall survival and progression-free survival. Functional annotation indicated an immune-modulatory role of LRP1 in ccRCC. LRP1 expression was significantly correlated with expressions of PBRM1, SETD2, and KDM5C. Positive correlations between LRP1 and pro-angiogenic factors ERAP1, SCG2, STAB1, and RUNX1 were observed. LRP1 expression was positively correlated with PD-L2 level. Negative correlations between LRP1 and anti-angiogenic factors EMCN and IL18 were observed. LRP1 expression was not associated with microvessel density (MVD) yet was negatively correlated with tumor-infiltrating lymphocytes (TIL).

CONCLUSION

LRP1 is associated with worsened prognosis in ccRCC and is related to cancer immune modulation. LRP1-targeted therapy can be of therapeutic potential.

Diagnostic Value of Serum Angiogenesis Markers in Ovarian Cancer Using Multiplex Immunoassay

As cancer development involves pathological vessel formation, 16 angiogenesis markers were evaluated as potential ovarian cancer (OC) biomarkers. Blood samples collected from 172 patients were divided based on histopathological result: OC (n = 38), borderline ovarian tumours (n = 6), non-malignant ovarian tumours (n = 62), healthy controls (n = 50) and 16 patients were excluded. Sixteen angiogenesis markers were measured using BioPlex Pro Human Cancer Biomarker Panel 1 immunoassay. Additionally, concentrations of cancer antigen 125 (CA125) and human epididymis protein 4 (HE4) were measured in patients with adnexal masses using electrochemiluminescence immunoassay. In the comparison between OC vs. non-OC, osteopontin achieved the highest area under the curve (AUC) of 0.79 (sensitivity 69%, specificity 78%). Multimarker models based on four to six markers (basic fibroblast growth factor-FGF-basic, follistatin, hepatocyte growth factor-HGF, osteopontin, platelet-derived growth factor AB/BB-PDGF-AB/BB, leptin) demonstrated higher discriminatory ability (AUC 0.80-0.81) than a single marker (AUC 0.79). When comparing OC with benign ovarian tumours, six markers had statistically different expression (osteopontin, leptin, follistatin, PDGF-AB/BB, HGF, FGF-basic). Osteopontin was the best single angiogenesis marker (AUC 0.825, sensitivity 72%, specificity 82%). A three-marker panel consisting of osteopontin, CA125 and HE4 better discriminated the groups (AUC 0.958) than HE4 or CA125 alone (AUC 0.941 and 0.932, respectively). Osteopontin should be further investigated as a potential biomarker in OC screening and differential diagnosis of ovarian tumours. Adding osteopontin to a panel of already used biomarkers (CA125 and HE4) significantly improves differential diagnosis between malignant and benign ovarian tumours.

Vascular endothelial growth factor expression correlates with serum CA125 and represents a useful tool in prediction of refractoriness to platinum-based chemotherapy and ascites formation in epithelial ovarian cancer

There is an increasing need for the identification of novel biological markers and potential therapeutic targets in epithelial ovarian cancer (EOC). Given the critical role of growth factors in the biology of EOC, we aimed in the present study to evaluate the intratumoral expressions of vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) proteins and their clinical relevance in a cohort of 100 patients with EOC. All patients received platinum-based chemotherapy after surgery. A comparative immunohistochemical study of normal ovarian and EOC tissues showed that both growth factors were expressed at higher levels in tumor samples. In our statistical analysis, while no association existed between the FGF expression status and the clinicopathological characteristics of patients, intratumoral VEGF was identified as a potential biomarker for the prediction of ascites formation. In addition, the expression status of VEGF appeared to independently predict overall survival and response to chemotherapy. Furthermore, a direct association was demonstrated between the pre-treatment VEGF expression and serum CA125 after three cycles of chemotherapy. In sum, we report for the first time to our knowledge the correlation between intratumoral VEGF and serum CA125 in EOC. Our data also shows the prognostic value of VEGF expression in EOC. These results suggest the potential value of intratumoral VEGF in patient stratification. Dual inhibition of VEGF and CA125 might bring about a better outcome for patients with EOC.

Molecular and clinical significance of fibroblast growth factor 2 (FGF2 /bFGF) in malignancies of solid and hematological cancers for personalized therapies

Fibroblast growth factor (FGF) signaling is essential for normal and cancer biology. Mammalian FGF family members participate in multiple signaling pathways by binding to heparan sulfate and FGF receptors (FGFR) with varying affinities. FGF2 is the prototype member of the FGF family and interacts with its receptor to mediate receptor dimerization, phosphorylation, and activation of signaling pathways, such as Ras-MAPK and PI3K pathways. Excessive mitogenic signaling through the FGF/FGFR axis may induce carcinogenic effects by promoting cancer progression and increasing the angiogenic potential, which can lead to metastatic tumor phenotypes. Dysregulated FGF/FGFR signaling is associated with aggressive cancer phenotypes, enhanced chemotherapy resistance and poor clinical outcomes. In vitro experimental settings have indicated that extracellular FGF2 affects proliferation, drug sensitivity, and apoptosis of cancer cells. Therapeutically targeting FGF2 and FGFR has been extensively assessed in multiple preclinical studies and numerous drugs and treatment options have been tested in clinical trials. Diagnostic assays are used to quantify FGF2, FGFRs, and downstream signaling molecules to better select a target patient population for higher efficacy of cancer therapies. This review focuses on the prognostic significance of FGF2 in cancer with emphasis on therapeutic intervention strategies for solid and hematological malignancies.

Vasohibin-1 expression inhibits advancement of ovarian cancer producing various angiogenic factors

Vasohibin‐1 (VASH1) is a negative feedback regulator of angiogenesis, the first to be discovered, and was identified in vascular endothelial growth factor (VEGF)‐stimulated vascular endothelial cells. Vasohibin‐1 inhibits abnormal vascularization induced by various angiogenic factors including fibroblast growth factor and platelet‐derived growth factor (PDGF), in addition to VEGF. By focusing on this characteristic of VASH1, we investigated the antitumor effects of VASH1 expression on ovarian cancer cells that produce different angiogenic factors. By using a high VEGF‐producing ovarian cancer cell line, SHIN‐3, and a high PDGF‐producing ovarian cancer cell line, KOC‐2S, the cells were transfected with either a VEGF antagonist, soluble VEGF receptor‐1 (sVEGFR‐1, or sFlt‐1), or VASH1 genes to establish their respective cellular expression. The characteristics of these transfectants were compared with controls. We previously reported that the expression of sFlt‐1 inhibited tumor vascularization and growth of high VEGF‐producing ovarian cancer cells, reduced peritoneal dissemination and ascites development, and prolonged the survival time of the host. However, in the current study, the expression of sFlt‐1 had no such effect on the high PDGF‐producing ovarian cancer cells used here, whereas VASH1 expression inhibited tumor vascularization and growth, not only in high VEGF‐producing cells, but also in high PDGF‐producing cells, reduced their peritoneal dissemination and ascites, and prolonged the survival time of the host. These results suggest that VASH1 is an effective treatment for ovarian cancer cells that produce different angiogenic factors.

Akt-activated endothelium constitutes the niche for residual disease and resistance to bevacizumab in ovarian cancer

Ovarian cancer is the second leading cause of cancer-related death in women worldwide. Despite optimal cytoreduction and adequate adjuvant therapies, initial tumor response is often followed by relapse suggesting the existence of a tumor niche. Targeted therapies have been evaluated in ovarian cancer to overcome resistant disease. Among them, antiangiogenic therapies inhibit new blood vessel growth, induce endothelial cell apoptosis, and block the incorporation of hematopoietic and endothelial progenitor cells into new blood vessels. Despite in vitro and in vivo successes, antivascular therapy with bevacizumab targeting VEGF-A has limited efficacy in ovarian cancer. The precise molecular mechanisms underlying clinical resistance to anti-VEGF therapies are not yet well understood. Among them, tumor and stromal heterogeneity might determine the treatment outcomes. The present study investigates whether abnormalities in the tumor endothelium may contribute to treatment resistance to bevacizumab and promote a residual microscopic disease. Here, we showed that ovarian cancer cells activate Akt phosphorylation in endothelial cells inducing resistance to bevacizumab leading to an autocrine loop based on FGF2 secretion. Altogether, our results point out the role of an activated endothelium in the resistance to bevacizumab and in the constitution of a niche for a residual disease.

Expression of IL-18, IL-18 binding protein, and IL-18 receptor by normal and cancerous human ovarian tissues: possible implication of IL-18 in the pathogenesis of ovarian carcinoma

Proinflammatory cytokine IL-18 has been shown to be elevated in the sera of ovarian carcinoma patients. The aim of the study was to examine the levels and cellular origin of IL-18, IL-18 binding protein, and IL-18 receptor in normal and cancerous ovarian tissues. Ovarian tissue samples were examined by immunohistochemical staining for IL-18, IL-18BP, and IL-18R and mRNA of these cytokines was analyzed with semiquantitative PT-PCR. IL-18 levels were significantly higher in cancerous ovarian tissues (P = 0.0007), IL-18BP levels were significantly higher in normal ovarian tissues (P = 0.04), and the ratio of IL-18/IL-18BP was significantly higher in cancerous ovarian tissues (P = 0.036). Cancerous ovarian tissues expressed significantly higher IL-18 mRNA levels (P = 0.025), while there was no difference in the expression of IL-18BP mRNA and IL-18R mRNA between cancerous and normal ovarian tissues. IL-18 and IL-18BP were expressed dominantly in the epithelial cells of both cancerous and normal ovarian tissues, while IL-18R was expressed dominantly in the epithelial cells of cancerous ovarian tissues but expressed similarly in the epithelial and stromal cells of normal cancerous tissues. This study indicates a possible role of IL-18, IL-18BP, and IL-18R in the pathogenesis of epithelial ovarian carcinoma.

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

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

Genetic variants in the fibroblast growth factor pathway as potential markers of ovarian cancer risk, therapeutic response, and clinical outcome

BACKGROUND

The fibroblast growth factor (FGF) and FGF receptor (FGFR) axis plays a critical role in tumorigenesis, but little is known of its influence in ovarian cancer. We sought to determine the association of genetic variants in the FGF pathway with risk, therapeutic response, and survival of patients with ovarian cancer.

METHODS

We matched 339 non-Hispanic white ovarian cancer cases with 349 healthy controls and genotyped them for 183 single-nucleotide polymorphisms (SNPs) from 24 FGF (fibroblast growth factor) and FGFR (fibroblast growth factor receptor) genes. Genetic associations for the main effect, gene-gene interactions, and the cumulative effect were determined.

RESULTS

Multiple SNPs in the FGF-FGFR axis were associated with an increased risk of ovarian cancer. In particular, FGF1 [fibroblast growth factor 1 (acidic)] SNP rs7727832 showed the most significant association with ovarian cancer (odds ratio, 2.27; 95% CI, 1.31-3.95). Ten SNPs were associated with a reduced risk of ovarian cancer. FGF18 (fibroblast growth factor 18) SNP rs3806929, FGF7 (fibroblast growth factor 7) SNP rs9920722, FGF23 (fibroblast growth factor 23) SNP rs12812339, and FGF5 (fibroblast growth factor 5) SNP rs3733336 were significantly associated with a favorable treatment response, with a reduction of risk of nonresponse of 40% to 60%. Eleven SNPs were significantly associated with overall survival. Of these SNPs, FGF23 rs7961824 was the most significantly associated with improved prognosis (hazard ratio, 0.55; 95% CI, 0.39-0.78) and was associated with significantly longer survival durations, compared with individuals with the common genotype at this locus (58.1 months vs. 38.0 months, P = 0.005). Survival tree analysis revealed FGF2 rs167428 as the primary factor contributing to overall survival.

CONCLUSIONS

Significant associations of genetic variants in the FGF pathway were associated with ovarian cancer risk, therapeutic response, and survival. The discovery of multiple SNPs in the FGF-FGFR pathway provides a molecular approach for risk assessment, monitoring therapeutic response, and prognosis.

The IL-18 antagonist IL-18-binding protein is produced in the human ovarian cancer microenvironment

PURPOSE

Interleukin (IL)-18 is an immune-enhancing cytokine, which induces IFN-γ production, T-helper 1 responses, and antitumor effects. In turn, IFN-γ stimulates IL-18-binding protein production, which blocks IL-18 activity. In view of the potential use of IL-18 in epithelial ovarian cancer (EOC) immunotherapy, here, we studied IL-18BP expression and its regulation by cytokines in EOC cells in vitro and in vivo.

EXPERIMENTAL DESIGN

Expression and production of IL-18BP in EOC cell lines, primary ovarian carcinomas, and the corresponding normal tissues, patients' serum, and ascites were investigated by immunochemistry, ELISA, screening of gene expression profiles, and reverse-transcription PCR.

RESULTS

Analysis of gene expression profiles revealed that IL18BP mRNA is increased in EOC tumors compared with normal ovary cells. Release of IL-18BP was detectable in EOC sera and to a greater extent in the ascites, indicating production at the tumor site. Indeed, immunochemical analyses on cells isolated from the ascites and on tumor sections indicated that IL-18BP is expressed in both tumor cells and tumor-associated leukocytes, which displayed a CD3-CD20-NKp46-CD13+CD14low phenotype. EOC cell lines do not constitutively express IL-18BP. However, its release is inducible both by IFN-γ stimulation in vitro and by xenotransplantation of EOC cells in immune-deficient mice, suggesting a role for the microenvironment. In vitro experiments and immunochemistry indicated that IL-27 is also involved in IL-18BP upregulation in EOC cell lines and primary cells through STAT1 activation. Together, these data indicate that IL-18BP, which is produced in EOC in response to microenvironmental factors, may inhibit endogenous or exogenous IL-18 activity.

RANTES and fibroblast growth factor 2 in jawbone cavitations: triggers for systemic disease?

Background

Jawbone cavitations (JC) are hollow dead spaces in jawbones with dying or dead bone marrow. These areas are defined as fatty degenerative osteonecrosis of the jawbone or neuralgia-inducing cavitational osteonecrosis and may produce facial pain. These afflictions have been linked to the immune system and chronic illnesses. Surgical debridement of JC is reported to lead to an improvement in immunological complaints, such as rheumatic, allergic, and other inflammatory diseases (ID). Little is known about the underlying cause/effect relationship.

Objectives

JC bone samples were analyzed to assess the expression and quantification of immune modulators that can play a role in the pathogenesis of IDs. The study supports a potential mechanism where JC is a mediating link in IDs.

Materials and methods

Samples of fatty softened bone taken from JCs were extracted from 31 patients. The specimens were analyzed by bead-based multiplex technology and tested for seven immune messengers.

Results

Regulated upon activation, normal T-cell expressed, and secreted (RANTES) and fibroblast growth factor (FGF)-2 were found at high levels in the JCs tested. Other cytokines could not be detected at excessive levels.

Discussion

The study confirms that JC is able to produce inflammatory messengers, primarily RANTES, and, secondarily, FGF-2. Both are implicated in many serious illnesses. The excessive levels of RANTES/FGF-2 in JC patients with amyotrophic lateral sclerosis, multiple sclerosis, rheumatoid arthritis, and breast cancer are compared to levels published in medical journals. Levels detected in JCs are higher than in the serum and cerebrospinal fluid of amyotrophic lateral sclerosis and multiple sclerosis patients and four-fold higher than in breast cancer tissue.

Conclusion

This study suggests that JC might serve as a fundamental cause of IDs, through RANTES/FGF-2 production. Thus, JC and implicated immune messengers represent an integrative aspect of IDs and serve as a possible cause. Removing JCs may be a key to reversing IDs. There is a need to raise awareness about JC throughout medicine and dentistry.

The OPCML tumor suppressor functions as a cell surface repressor-adaptor, negatively regulating receptor tyrosine kinases in epithelial ovarian cancer

Epithelial ovarian cancer is the leading cause of death from gynecologic malignancy, and its molecular basis is poorly understood. We previously demonstrated that opioid binding protein cell adhesion molecule (OPCML) was frequently epigenetically inactivated in epithelial ovarian cancers, with tumor suppressor function in vitro and in vivo. Here, we further show the clinical relevance of OPCML and demonstrate that OPCML functions by a novel mechanism in epithelial ovarian cancer cell lines and normal ovarian surface epithelial cells by regulating a specific repertoire of receptor tyrosine kinases: EPHA2, FGFR1, FGFR3, HER2, and HER4. OPCML negatively regulates receptor tyrosine kinases by binding their extracellular domains, altering trafficking via nonclathrin-dependent endocytosis, and promoting their degradation via a polyubiquitination-associated proteasomal mechanism leading to signaling and growth inhibition. Exogenous recombinant OPCML domain 1-3 protein inhibited the cell growth of epithelial ovarian cancers cell in vitro and in vivo in 2 murine ovarian cancer intraperitoneal models that used an identical mechanism. These findings demonstrate a novel mechanism of OPCML-mediated tumor suppression and provide a proof-of-concept for recombinant OPCML protein therapy in epithelial ovarian cancers.

SIGNIFICANCE

The OPCML tumor suppressor negatively regulates a specific spectrum of receptor tyrosine kinases in ovarian cancer cells by binding to their extracellular domain and altering trafficking to a nonclathrin, caveolin-1–associated endosomal pathway that results in receptor tyrosine kinase polyubiquitination and proteasomal degradation. Recombinant OPCML domain 1-3 recapitulates this mechanism and may allow for the implementation of an extracellular tumor-suppressor replacement strategy.

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

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

Subtype specific elevated expression of hyaluronidase-1 (HYAL-1) in epithelial ovarian cancer

Background

Epithelial ovarian cancer (EOC) is morphologically heterogeneous being classified as serous, endometrioid, clear cell, or mucinous. Molecular genetic analysis has suggested a role for tumor suppressor genes located at chromosome 3p in serous EOC pathogenesis. Our objective was to evaluate the expression of HYAL1, located at chromosome 3p21.3, in these EOC subtypes, and to investigate its correlation with the expression of steroid hormone receptors.

Methodology/Principal Findings

We determined the mRNA expression of HYAL1, estrogen receptor (ER)-α, ERβ and progesterone receptor (PR) in EOC tumor samples and cell lines using quantitative RT-PCR. We also examined the expression of these genes in a publicly available microarray dataset. HYAL-1 enzyme activity was measured in EOC cell lines and in plasma samples from patients. We found that HYAL1 mRNA expression was elevated in clear cell and mucinous EOC tissue samples, but not in serous and endometrioid samples, normal ovaries or benign tumors. Similar results were obtained by two different techniques and with tissue sample cohorts from two independent institutions. Concordantly, HYAL1 mRNA levels and enzymatic activity were elevated only in EOC cell lines derived from clear cell and mucinous subtypes. We also showed that HYAL1 mRNA was inversely correlated to that of ERα specifically in clear cell and mucinous EOCs. Additionally, ectopic expression of ERα in a clear cell EOC cell line (ER- and PR-negative) induced 50% reduction of HYAL1 mRNA expression, supporting a role of ERα in HYAL1 gene regulation. Significantly, HYAL-1 activity was also high in the plasma of patients with these EOC subtypes.

Conclusions/Significance

This is the first report showing high HYAL-1 levels in EOC and demonstrating HYAL1 gene repression by ERα. Our results identify Hyaluronidase-1 as a potential target/biomarker for clear cell and mucinous EOCs and especially in tumors with low ERα levels.

Interleukin (IL)-18, a biomarker of human ovarian carcinoma, is predominantly released as biologically inactive precursor

Interleukin (IL)-18 is a proinflammatory and immune-enhancing cytokine, which exerts antitumor effects in vivo, mediated by the induction of interferon (IFN)γ. We previously reported that IL-18 processing is defective in epithelial ovarian carcinoma (EOC) cells, which secrete an inactive precursor (pro-IL-18) in vitro. In addition, IL-18 was reported as a potential biomarker of EOC. Here, we further investigated its role as a serological marker in human EOC and addressed its possible biological activity in vivo. Our data indicate that immunoreactive IL-18 is increased in EOC patients' sera at diagnosis as compared with age-matched healthy women. IL-18 levels were higher in the ascitic fluids than in sera, suggesting a local production in the peritoneal cavity. Indeed, immunohistochemical analysis of tumors showed IL-18 expression in cytokeratine-positive neoplastic cells, although also scattered histiocytes and some lymphoid cells stained for IL-18. The detection of human IL-18 in sera and ascitic fluids of immunodeficient mice, orthotopically implanted with human EOC cells, further suggested that circulating IL-18 is tumor-derived. However, IL-18 is not an EOC specific biomarker, as increased serum levels were found also in some endometrial cancer patients. By means of a new monoclonal antibody, we characterized IL-18 present in the ascitic fluid as pro-IL-18, which is biologically inactive. Accordingly, IFNγ was not increased in EOC patients' sera and ascitic fluids and showed no correlation with IL-18 levels. Altogether these data indicate that IL-18 in EOC fluids is predominantly tumor-derived and that its lack of biological activity may represent a mechanism of tumor-escape.

Oviductal glycoprotein (OVGP1, MUC9): a differentiation-based mucin present in serum of women with ovarian cancer

INTRODUCTION

Epithelial ovarian carcinomas are highly lethal because most are detected at late stages. A previous immunohistochemical analysis showed that oviductal glycoprotein 1 (OVGP1), a secretory product of the oviductal epithelium under estrogen dominance, is produced predominantly by borderline and low-grade malignant epithelial ovarian tumors. In the present study, we investigated OVGP1 as a possible serum marker for the detection of ovarian cancer.

METHODS

We generated a highly specific monoclonal antibody, clone 7E10, to human OVGP1. Using 7E10 and a polyclonal antibody, a sandwich enzyme-linked immunosorbent assay was developed to assay OVGP1 levels in 135 normal sera, and sera from 21 benign tumors, 12 borderline tumors, and 87 ovarian cancers (18, grade 1-2 serous; 44, grade 3 serous; 10, mucinous; 10, clear cell; and 5, endometrioid).

RESULTS

Using a 95% confidence interval cutoff from the mean of normal postmenopausal sera, median OVGP1 levels were elevated in the sera from 75% of the women with borderline tumors and 80% of the women with mucinous, 60% with clear cell, 59% with grade 1 and 2 serous, 22% with grade 3 serous, and 0% with endometrioid carcinomas. By stage, OVGP1 levels were highest in the sera from the borderline tumors, stage I and II serous carcinomas, and mucinous carcinomas. OVGP1 levels varied independently of cancer antigen 125 (CA125).

CONCLUSIONS

Increases in OVGP1 serum levels vary with ovarian tumor histotypes and stages. Being differentiation based, OVGP1 seems to detect a different spectrum of ovarian epithelial cancers than other markers and thus should be a useful adjunct for more accurate detection, particularly of early serous ovarian cancers and mucinous carcinomas, which tend to lack increased CA125.

Effect of bFGF on invasion of ovarian cancer cells through the regulation of Ets-1 and urokinase-type plasminogen activator

The aim of the study was to explore the role of basic fibroblast growth factor (bFGF) in ovarian cancer progression. This was done by investigating the effects of bFGF on both the secretion of urokinase-type plasminogen activator (uPA) and the invasion of tumor cells in SKOV(3) ovarian cancer cells. Human ovarian cancer cell line SKOV(3) was cultured in vitro. The expression of uPA gene and protein was induced in SKOV(3) cells; the impact of bFGF on the expression of uPA gene in SKOV(3) cells was studied by RT-PCR, and the impact of bFGF on the expression of uPA protein was tested by ELISA. Ets-1 antisense oligonucleotides were transfected into SKOV(3) cells by liposome protocol. The effects of bFGF on Ets-1 expression and the invasion ability of SKOV(3) cells were determined both before and after exposure to different concentrations of bFGF for 24 h. The expression of both uPA gene and protein was induced in SKOV(3) cells, p < 0.05. The expression of uPA was suppressed by Ets-1 antisense oligonucleotides in SKOV(3) cells, p < 0.05. The invasion ability of SKOV(3) cells was increased by 2.3-fold, and this effect was also suppressed by Ets-1 antisense oligonucleotides. bFGF can enhance the invasion ability of ovarian cancer cells in vitro by inducing the expression of uPA, and this effect is also regulated by the transcription factor Ets-1.

Increased immunogenicity of surviving tumor cells enables cooperation between liposomal doxorubicin and IL-18

Background

Liposomal doxorubicin (Doxil) is a cytotoxic chemotherapy drug with a favorable hematologic toxicity profile. Its active drug, doxorubicin, has interesting immunomodulatory properties. Here, the effects of Doxil on surviving tumor cell immunophenotype were investigated.

Methods

Using ID8 murine ovarian cancer cells, the immunomodulatory effects of Doxil were studied by measuring its impact on ovarian cancer cell expression of MHC class-I and Fas, and susceptibility to immune attack in vitro. To evaluate the ability of Doxil to cooperate with cancer immunotherapy, the interaction between Doxil and Interleukin 18 (IL-18), a pleiotropic immunostimulatory cytokine, was investigated in vivo in mice bearing ID8-Vegf tumors.

Results

While Doxil killed ID8 tumor cells in a dose-dependent manner, tumor cells escaping Doxil-induced apoptosis upregulated surface expression of MHC-I and Fas, and were sensitized to CTL killing and Fas-mediated death in vitro. We therefore tested the hypothesis that the combination of immunotherapy with Doxil provides positive interactions. Combination IL-18 and Doxil significantly suppressed tumor growth compared with either monotherapy in vivo and uniquely resulted in complete tumor regression and long term antitumor protection in a significant proportion of mice.

Conclusion

These data demonstrate that Doxil favorably changes the immunophenotype of a large fraction of the tumor that escapes direct killing thus creating an opportunity to expand tumor killing by immunotherapy, which can be capitalized through addition of IL-18 in vivo.

The chemiluminescence based Ziplex automated workstation focus array reproduces ovarian cancer Affymetrix GeneChip expression profiles

Background

As gene expression signatures may serve as biomarkers, there is a need to develop technologies based on mRNA expression patterns that are adaptable for translational research. Xceed Molecular has recently developed a Ziplex^® technology, that can assay for gene expression of a discrete number of genes as a focused array. The present study has evaluated the reproducibility of the Ziplex system as applied to ovarian cancer research of genes shown to exhibit distinct expression profiles initially assessed by Affymetrix GeneChip^® analyses.

Methods

The new chemiluminescence-based Ziplex^® gene expression array technology was evaluated for the expression of 93 genes selected based on their Affymetrix GeneChip^® profiles as applied to ovarian cancer research. Probe design was based on the Affymetrix target sequence that favors the 3' UTR of transcripts in order to maximize reproducibility across platforms. Gene expression analysis was performed using the Ziplex Automated Workstation. Statistical analyses were performed to evaluate reproducibility of both the magnitude of expression and differences between normal and tumor samples by correlation analyses, fold change differences and statistical significance testing.

Results

Expressions of 82 of 93 (88.2%) genes were highly correlated (p < 0.01) in a comparison of the two platforms. Overall, 75 of 93 (80.6%) genes exhibited consistent results in normal versus tumor tissue comparisons for both platforms (p < 0.001). The fold change differences were concordant for 87 of 93 (94%) genes, where there was agreement between the platforms regarding statistical significance for 71 (76%) of 87 genes. There was a strong agreement between the two platforms as shown by comparisons of log₂ fold differences of gene expression between tumor versus normal samples (R = 0.93) and by Bland-Altman analysis, where greater than 90% of expression values fell within the 95% limits of agreement.

Conclusion

Overall concordance of gene expression patterns based on correlations, statistical significance between tumor and normal ovary data, and fold changes was consistent between the Ziplex and Affymetrix platforms. The reproducibility and ease-of-use of the technology suggests that the Ziplex array is a suitable platform for translational research.

BMP-2 signaling in ovarian cancer and its association with poor prognosis

BACKGROUND

We previously observed the over-expression of BMP-2 in primary cultures of epithelial ovarian cancer (EOC) cells as compared to normal epithelial cells based on Affymetrix microarray profiling 1. Here we investigate the effect of BMP-2 on several parameters of ovarian cancer tumorigenesis using the TOV-2223, TOV-1946 and TOV-112D EOC cell lines.

METHODS

We treated each EOC cell line with recombinant BMP-2 and assayed various parameters associated with tumorigenesis. More specifically, cell signaling events induced by BMP-2 treatment were investigated by western-blot using anti-phosphospecific antibodies. Induction of Id1, Snail and Smad6 mRNA expression was investigated by real time RT-PCR. The ability of cells to migrate was tested using the scratch assay. Cell-cell adhesion was analyzed by the ability of cells to form spheroids. We also investigated BMP-2 expression in tissue samples from a series of EOC patients.

RESULTS

Treatment of these cell lines with recombinant BMP-2 induced a rapid phosphorylation of Smad1/5/8 and Erk MAPKs. Increased expression of Id1, Smad6 and Snail mRNAs was also observed. Only in the TOV-2223 cell line were these signaling events accompanied by an alteration in cell proliferation. We also observed that BMP-2 efficiently increased the motility of all three cell lines. In contrast, BMP-2 treatment decreased the ability of TOV-1946 and TOV-112D cell lines to form spheroids indicating an inhibition of cell-cell adhesion. The expression of BMP-2 in tumor tissues from patients was inversely correlated with survival.

CONCLUSION

These results suggest that EOC cell secretion of BMP-2 in the tumor environment contributes to a modification of tumor cell behavior through a change in motility and adherence. We also show that BMP-2 expression in tumor tissues is associated with a poorer prognosis for ovarian cancer patients.

Molecular and pathological signatures of epithelial-mesenchymal transitions at the cancer invasion front

Reduction of epithelial cell-cell adhesion via the transcriptional repression of cadherins in combination with the acquisition of mesenchymal properties are key determinants of epithelial-mesenchymal transition (EMT). EMT is associated with early stages of carcinogenesis, cancer invasion and recurrence. Furthermore, the tumor stroma dictates EMT through intensive bidirectional communication. The pathological analysis of EMT signatures is critically, especially to determine the presence of cancer cells at the resection margins of a tumor. When diffusion barriers disappear, EMT markers may be detected in sera from cancer patients. The detection of EMT signatures is not only important for diagnosis but can also be exploited to enhance classical chemotherapy treatments. In conclusion, further detailed understanding of the contextual cues and molecular mediators that control EMT will be required in order to develop diagnostic tools and small molecule inhibitors with potential clinical implications.

Suction blister fluid as potential body fluid for biomarker proteins

Early diagnosis is important for effective disease management. Measurement of biomarkers present at the local level of the skin could be advantageous in facilitating the diagnostic process. The analysis of the proteome of suction blister fluid, representative for the interstitial fluid of the skin, is therefore a desirable first step in the search for potential biomarkers involved in biological pathways of particular diseases. Here, we describe a global analysis of the suction blister fluid proteome as potential body fluid for biomarker proteins. The suction blister fluid proteome was compared with a serum proteome analyzed using identical protocols. By using stringent criteria allowing less than 1% false positive identifications, we were able to detect, using identical experimental conditions and amount of starting material, 401 proteins in suction blister fluid and 240 proteins in serum. As a major result of our analysis we construct a prejudiced list of 34 proteins, relatively highly and uniquely detected in suction blister fluid as compared to serum, with established and putative characteristics as biomarkers. We conclude that suction blister fluid might potentially serve as a good alternative biomarker body fluid for diseases that involve the skin.

Clinical and experimental approaches to the pathophysiology of interleukin-18 in cancer progression

Interleukin-18 (IL-18, interferon [IFN]-gamma-inducing factor) is a proinflammatory cytokine converted to a biologically active molecule by interleukin (IL)-1beta converting enzyme (caspase-1). A wide range of normal and cancer cell types can produce and respond to IL-18 through a specific receptor (IL-18R) belonging to the toll-like receptor family. The activity of IL-18 is regulated by IL-18-binding protein (IL-18bp), a secreted protein possessing the ability to neutralize IL-18 and whose blood level is affected by renal function and is induced by IFNgamma. IL-18 plays a central role in inflammation and immune response, contributing to the pathogenesis and pathophysiology of infectious and inflammatory diseases. Because immune-stimulating effects of IL-18 have antineoplastic properties, IL-18 has been proposed as a novel adjuvant therapy against cancer. However, IL-18 increases in the blood of the majority of cancer patients and has been associated with disease progression and, in some cancer types, with metastatic recurrence risk and poor clinical outcome and survival. Under experimental conditions, cancer cells can also escape immune recognition, increase their adherence to the microvascular wall and even induce production of angiogenic and tumor growth-stimulating factors via IL-18-dependent mechanism. This is particularly visible in melanoma cells. Thus, the role of IL-18 in cancer progression and metastasis remains controversial. This review examines the clinical correlations and biological effects of IL-18 during cancer development and highlights recent experimental insights into prometastatic and proangiogenic effects of IL-18 and the use of IL-18bp against cancer progression.