Francis Jacob

No benefit from combining HE4 and CA125 as ovarian tumor markers in a clinical setting

OBJECTIVE About 70% of epithelial ovarian cancer patients (EOC) are diagnosed at advanced stage with a five-year survival rate of only 30%. Whilst CA125 detects peritoneally-spread disease, it has limited sensitivity for early cancers, many of which are potentially curable. METHODS We compared the new commercially available tumor marker HE4 with CA125 individually, in combination, within the risk of malignancy index (RMI) and the newly defined risk of malignancy algorithm (ROMA). Our prospectively-collected cohort of 160 patients consisted of healthy controls, benign diseases, and borderline tumors/adenocarcinomas of ovarian, tubal, peritoneal and endometrial origin. HE4 and CA125 were measured in serum using standardized ELISA. RESULTS Both markers showed similar diagnostic performance in the detection of EOC at clinically defined thresholds (CA125 35U/ml; HE4 70pM) but HE4 was not elevated in endometriosis. Comparison of non-malignant diagnoses (n=71) versus early stage ovarian and tubal cancers (n=19) revealed that HE4 and ROMA displayed the best diagnostic performance (AUC 0.86/0.87, specificity 85.9%/87.3% and sensitivity 78.9%/78.9%, respectively). Whilst RMICA125 detects peritoneal cancer better than all other models (AUC 0.99, specificity 97.2%, sensitivity 80.0%), there is no other detection benefit from RMI compared to HE4 alone or included in ROMA. CONCLUSIONS The major advantage of HE4 lies in its specificity and improved detection of borderline tumors and early stage ovarian and tubal cancers. HE4 is superior to CA125 with or without RMI and ROMA indices. However, we see no benefit from combining both markers in clinical practice.

Apyrases (Nucleoside Triphosphate-Diphosphohydrolases) Play a Key Role in Growth Control in Arabidopsis

Expression of two Arabidopsis (Arabidopsis thaliana) apyrase (nucleoside triphosphate-diphosphohydrolase) genes with high similarity, APY1 and APY2, was analyzed during seedling development and under different light treatments using β-glucuronidase fusion constructs with the promoters of both genes. As evaluated by β-glucuronidase staining and independently confirmed by other methods, the highest expression of both apyrases was in rapidly growing tissues and/or tissues that accumulate high auxin levels. Red-light treatment of etiolated seedlings suppressed the protein and message level of both apyrases at least as rapidly as it inhibited hypocotyl growth. Adult apy1 and apy2 single mutants had near-normal growth, but apy1apy2 double-knockout plants were dwarf, due primarily to reduced cell elongation. Pollen tubes and etiolated hypocotyls overexpressing an apyrase had faster growth rates than wild-type plants. Growing pollen tubes released ATP into the growth medium and suppression of apyrase activity by antiapyrase antibodies or by inhibitors simultaneously increased medium ATP levels and inhibited pollen tube growth. These results imply that APY1 and APY2, like their homologs in animals, act to reduce the concentration of extracellular nucleotides, and that this function is important for the regulation of growth in Arabidopsis.

Serum antiglycan antibody detection of nonmucinous ovarian cancers by using a printed glycan array.

Epithelial ovarian cancer has the highest mortality rate among gynecological cancers. Altered glycosylation is associated with oncogenic transformation producing tumor‐associated carbohydrate antigens. We investigated the potential of natural occurring antiglycan antibodies in the diagnosis of ovarian cancer by using printed glycan array. Antiglycan antibodies bound to 203 chemically synthesized printed glycans were detected via biotin‐streptavidin fluorescence system in serum of women with normal operative findings (healthy controls; n = 24) and nonmucinous borderline or ovarian cancer of various FIGO stages (n = 33). Data were validated measuring blood group associated di‐, tri and tetrasaccharide antigens on known ABO blood groups. Antiglycan antibodies demonstrated high reproducibility (rc > 0.9). Cluster analysis identified repetitive patterns of specific core carbohydrate structures: 11 N‐linked glycans, 3 O‐linked glycans and 2 glycosphingolipids. Biomarker detection revealed 24 glycans including P1 (Galα1–4Galβ1–4GlcNAcβ; p < 0.001) significantly discriminating between (low‐) malignant tumors and healthy controls. Comparable sensitivity and specificity with tumor marker CA125 was achieved by a panel of multivariate selected and linear combined antiglycan antibody signals (79.2 and 84.8%, respectively). Our findings demonstrate the potential of glycan arrays in the development of a new generation of biomarkers for ovarian cancer.

MELK expression in ovarian cancer correlates with poor outcome and its inhibition by OTSSP167 abrogates proliferation and viability of ovarian cancer cells

OBJECTIVE Maternal embryonic leucine-zipper kinase (MELK) shows oncogenic properties in basal-like breast cancer, a cancer subtype sharing common molecular features with high-grade serous ovarian cancer. We examined the potential of MELK as a molecular and pharmacological target for treatment of epithelial ovarian cancer (EOC). METHODS/MATERIALS Bioinformatic analysis was performed on nine OC transcriptomic data sets totaling 1241 patients. Effects of MELK depletion by shRNA or inhibition by OTSSP167 in cell lines were assessed by colony formation and MTT (proliferation) assays, Western blotting (apoptosis), and flow cytometry (cell cycle analysis). RESULTS Elevated MELK expression was correlated with histological grading (n=6 data sets, p<0.05) and progression-free survival (HR 5.73, p<0.01) in OC patients and elevated MELK expression in other cancers with disease-free survival (n=3495, HR 1.071, p<0.001). Inhibition or depletion of MELK reduced cell proliferation and anchorage-dependent and -independent growth in various OC cell lines through a G2/M cell cycle arrest, eventually resulting in apoptosis. OTSSP167 retained its cytotoxicity in Cisplatin- and Paclitaxel-resistant IGROV1 and TYK-nu OC cells and sensitized OVCAR8 cells to Carboplatin but not Paclitaxel. CONCLUSION MELK inhibition by OTSSP167 may thus present a strategy to treat patients with aggressive, progressive, and recurrent ovarian cancer.

A platform for the structural characterization of glycans enzymatically released from glycosphingolipids extracted from tissue and cells

RATIONALE Glycosphingolipids (GSLs) constitute a highly diverse class of glyco-conjugates which are involved in many aspects of cell membrane function and disease. The isolation, detection and structural characterization of the carbohydrate (glycan) component of GSLs are particularly challenging given their structural heterogeneity and thus rely on the development of sensitive, analytical technologies. METHODS Neutral and acidic GSL standards were immobilized onto polyvinylidene difluoride (PVDF) membranes and glycans were enzymatically released using endoglycoceramidase II (EGCase II), separated by porous graphitized carbon (PGC) liquid chromatography and structurally characterized by negative ion mode electrospray ionization tandem mass spectrometry (PGC-LC/ESI-MS/MS). This approach was then employed for GSLs isolated from 100 mg of serous and endometrioid cancer tissue and from cell line (10(7) cells) samples. RESULTS Glycans were released from GSL standards comprising of ganglio-, asialo-ganglio- and the relatively resistant globo-series glycans, using as little as 1 mU of enzyme and 2 µg of GSL. The platform of analysis was then applied to GSLs isolated from tissue and cell line samples and the released isomeric and isobaric glycan structures were chromatographically resolved on PGC and characterized by comparison with the MS(2) fragment ion spectra of the glycan standards and by application of known structural MS(2) fragment ions. This approach identified several (neo-)lacto-, globo- and ganglio-series glycans and facilitated the discrimination of isomeric structures containing Lewis A, H type 1 and type 2 blood group antigens and sialyl-tetraosylceramides. CONCLUSION We describe a relatively simple, detergent-free, enzymatic release of glycans from PVDF-immobilized GSLs, followed by the detailed structural analysis afforded by PGC-LC-ESI-MS/MS, to offer a versatile method for the analysis of tumour and cell-derived GSL-glycans. The method uses the potential of MS(2) fragmentation in negative ion ESI mode to characterize, in detail, the biologically relevant glycan structures derived from GSLs.

Glucosylceramide synthase inhibitors differentially affect expression of glycosphingolipids

Glucosylceramide synthase (GCS) catalyzes the first committed step in the biosynthesis of glucosylceramide (GlcCer)-related glycosphingolipids (GSLs). Although inhibitors of GCS, PPMP and PDMP have been widely used to elucidate their biological function and relevance, our comprehensive literature review revealed that the available data are ambiguous. We therefore investigated whether and to what extent GCS inhibitors affect the expression of lactosylceramide (LacCer), neolacto (nLc4 and P1), ganglio (GM1 and GD3) and globo (Gb3 and SSEA3) series GSLs in a panel of human cancer cell lines using flow cytometry, a commonly applied method investigating cell-surface GSLs after GCS inhibition. Their cell-surface GSL expression considerably varied among cell lines and more importantly, sublethal concentrations (IC10) of both inhibitors preferentially and significantly reduced the expression of Gb3 in the cancer cell lines IGROV1, BG1, HT29 and T47D, whereas SSEA3 was only reduced in BG1. Unexpectedly, the neolacto and ganglio series was not affected. LacCer, the precursor of all GlcCer-related GSL, was significantly reduced only in BG1 cells treated with PPMP. Future research questions addressing particular GSLs require careful consideration; our results indicate that the extent to which there is a decrease in the expression of one or more particular GSLs is dependent on the cell line under investigation, the type of GCS inhibitor and exposure duration.

Letrozole may be a valuable maintenance treatment in high-grade serous ovarian cancer patients

OBJECTIVES Endocrine therapy is used as maintenance in estrogen receptor (ER) positive breast cancers and has been proposed in low-grade serous ovarian cancers (LGSOC). Here we examine a rationale for its use as maintenance in high-grade serous ovarian cancers (HGSOC). METHODS We accessed the TCGA PANCAN dataset to evaluate the expression of ESR1. ESR1 expression data on all cancers (n=8901) and HGSOC (n=527) were followed by investigation of ER expression via immunohistochemistry (IHC) (n=4071). The same was performed in an independent cohort for matched primary and recurrent HGSOC (n=80). Finally, newly diagnosed ER+ HGSOC patients were offered a maintenance therapy with Letrozole. RESULTS ESR1 was strongly expressed in similar levels in HGSOC as in breast cancer. We found a strong ER expression via IHC in both the primary and matched recurrent HGSOC, particularly in the Platinum-resistant subgroup. The additional use of Letrozole as maintenance treatment was associated with a significantly prolonged recurrence free interval (after 24months 60% when taking Letrozole versus 38.5% in the control group; p=0.035; RFS: IC50 reached by one subject versus 13.2months). This effect was also present in patients treated additionally with Bevacizumab; 20.8% of patients had no recurrence after 12months compared to 87.5% when taking Letrozole in addition to Bevacizumab (p=0.026). CONCLUSIONS Primary HGSOC have a slightly higher ESR1 than and a similar ER expression breast cancer where aromatase inhibitor maintenance is routine for decades. Here we demonstrate evidence for the usefulness of Letrozole in HGSOC, particularly in patients with chemotherapy resistance or residual disease.

Tissue glycomics distinguish tumour sites in women with advanced serous adenocarcinoma

In the era of precision medicine, the tailoring of cancer treatment is increasingly important as we transition from organ‐based diagnosis towards a more comprehensive and patient‐centric molecular diagnosis. This is particularly the case for high‐grade serous adenocarcinomas of the ovary and peritoneum, which are commonly diagnosed at an advanced stage, and collectively treated and managed similarly. We characterized the N‐ and O‐glycome of serous ovarian (OC) and peritoneal cancer (PC) tissues using PGC‐LC‐ESI‐IT‐MS/MS profiling and validated the discriminatory glycans and their corresponding glyco‐gene expression levels using cell lines and transcriptomic data from 232 patients. Overall, the N‐ and O‐glycan repertoires of both cancer types were found to comprise mostly of α2,6‐sialylated glycan structures, with the majority of N‐glycans displaying the biantennary mono‐ and disialylation as well as bisecting‐type biantennary glycans. The MS profiling by PGC‐LC also revealed several glycan structural isomers that corresponded to LacdiNAc‐type (GalNAcβ1‐4GlcNAc) motifs that were unique to the serous ovarian cancers and that correlated with elevated gene expression of B4GALNT3 and B4GALNT4 in patients with serous cancer. Statistical evaluation of the discriminatory glycans also revealed 13 N‐ and 3 O‐glycans (P < 0.05) that significantly discriminated tumour‐sampling sites, with LacdiNAc‐type N‐glycans (m/z 1205.02− and m/z 1059.42−) being associated with ovarian‐derived cancer tissue and bisecting GlcNAc‐type (m/z 994.92−) and branched N‐glycans (m/z 1294.02− and m/z 1148.42−) upregulated at the metastatic sites. Hence, we demonstrate for the first time that OC and PC display distinct molecular signatures at both their glycomic and transcriptomic levels. These signatures may have potential utility for the development of accurate diagnosis and personalized treatments.

Naturally occurring anti-glycan antibodies binding to Globo H-expressing cells identify ovarian cancer patients

BackgroundGlycosphingolipids are important compounds of the plasma membrane of mammalian cells and a number of them have been associated with malignant transformation and progression, reinforcing tumour aggressiveness and metastasis. Here we investigated the levels of naturally occurring anti-glycan antibodies to Globo H in blood plasma obtained from high-grade serous ovarian cancer patients (SOC) and women without gynaecological malignancies (control) using suspension glycan array technology employing chemically synthesized glycans as antibody targets.ResultsWe found that anti-human Globo H IgG antibodies were able to significantly discriminate SOC from controls (P < 0.05). A combination with the clinically used tumour marker CA125 increased the diagnostic performance (AUC 0.8711). We next compared suspension array with standard flow cytometry in plasma samples and found that the level of anti-Globo H antibodies highly correlated (r = 0.992). The incubation of plasma-derived anti-glycan antibodies with chemically synthesized (presented on fluorescence microspheres) and native Globo H (expressed on Globo H-positive cell lines) revealed strong reactivity of naturally occurring human anti-Globo H antibodies towards its antigen expressed on ovarian cancer cells.ConclusionsOur data demonstrate that human plasma-derived antibodies to Globo H as well as the presence of the antigen might be considered as therapeutic option in ovarian cancer.

Prominent oncogenic roles of EVI1 in breast carcinoma

Overexpression of the EVI1 oncogene is associated typically with aggressive myeloid leukemia, but is also detectable in breast carcinoma where its contributions are unexplored. Analyzing a tissue microarray of 608 breast carcinoma patient specimens, we documented EVI1 overexpression in both estrogen receptor-positive (ER+) and estrogen receptor-negative (ER-) breast carcinomas. Here, we report prognostic relevance of EVI1 overexpression in triple-negative breast carcinoma but not in the HER2-positive breast carcinoma subset. In human breast cancer cells, EVI1 silencing reduced proliferation, apoptosis resistance, and tumorigenicity, effects rescued by estrogen supplementation in ER+ breast carcinoma cells. Estrogen addition restored ERK phosphorylation in EVI1-silenced cells, suggesting that EVI1 and estradiol signaling merge in MAPK activation. Conversely, EVI1 silencing had no effect on constitutive ERK activity in HER2+ breast carcinoma cells. Microarray analyses revealed G-protein-coupled receptor (GPR) signaling as a prominent EVI1 effector mechanism in breast carcinoma. Among others, the GPR54-ligand KISS1 was identified as a direct transcriptional target of EVI1, which together with other EVI1-dependent cell motility factors such as RHOJ regulated breast carcinoma cell migration. Overall, our results establish the oncogenic contributions of EVI1 in ER- and HER2-negative subsets of breast cancer. Cancer Res; 77(8); 2148-60. ©2017 AACR.