Gudrun Hager

1,25(OH)2 vitamin D3 induces elevated expression of the cell cycle-regulating genes P21 and P27 in squamous carcinoma cell lines of the head and neck.

The biologically active form of vitamin D3, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], inhibits proliferation and induces differentiation for various malignant cells, including squamous cell carcinoma cell lines of the head and neck (SCCHN). These effects are due to an arrest of cells in the G0/G1 phase of the cell cycle and are predominantly mediated by the vitamin D receptor. To further explore the molecular mechanisms of the antiproliferative activity in SCCHN we studied the influence of 1,25(OH)2D3 on the expression of the G1 phase-regulating proteins cyclin D1, p21 and p27. Furthermore, as a direct target of G1 protein complexes, we investigated the phosphorylation status of the retinoblastoma protein (pRb). Synchronized cells of 2 SCCHN cell lines [JPPA (laryngeal carcinoma) and SCC 9 (tongue carcinoma)] and human immortalized keratinocytes (HaCaT) were cultured for 96 h in the presence or absence (ethanol as control) of 1,25(OH)2D3 (10(-7) M). At various time intervals the cell cycle status was detected by fluorescence-activated cell sorting (FACS) analysis and in parallel the expression of cell cycle-regulating proteins was determined at the protein and mRNA levels. In all cell lines tested 1,25(OH)2D3 caused an arrest of cells in the G0/G1 phase of the cell cycle and markedly induced the expression of the inhibitors p21 and p27. No influence was detectable on the expression of cyclin D1. Induction of p21 and p27 mRNA revealed transcriptional regulation by the vitamin D receptor. Simultaneously, hyperphosphorylated pRb was transformed to the hypophosphorylated form. Our results demonstrate that the biologically active form of vitamin D3 directly regulates the expression of p21 and p27, inducing a G0/G1 phase arrest: one mechanism by which 1,25(OH)2D3 controls cell proliferation inSCCHN.The biologically active form of vitamin D3, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], inhibits proliferation and induces differentiation for various malignant cells, including squamous cell carcinoma cell lines of the head and neck (SCCHN). These effects are due to an arrest of cells in the G0/G1 phase of the cell cycle and are predominantly mediated by the vitamin D receptor. To further explore the molecular mechanisms of the antiproliferative activity in SCCHN we studied the influence of 1,25(OH)2D3 on the expression of the G1 phase-regulating proteins cyclin D1, p21 and p27. Furthermore, as a direct target of G1 protein complexes, we investigated the phosphorylation status of the retinoblastoma protein (pRb). Synchronized cells of 2 SCCHN cell lines [JPPA (laryngeal carcinoma) and SCC 9 (tongue carcinoma)] and human immortalized keratinocytes (HaCaT) were cultured for 96 h in the presence or absence (ethanol as control) of 1,25(OH)2D3 (10-7 M). At various time intervals the cell cycle status was detected by fluorescence-activated cell sorting (FACS) analysis and in parallel the expression of cell cycle-regulating proteins was determined at the protein and mRNA levels. In all cell lines tested 1,25(OH)2D3 caused an arrest of cells in the G0/G1 phase of the cell cycle and markedly induced the expression of the inhibitors p21 and p27. No influence was detectable on the expression of cyclin D1. Induction of p21 and p27 mRNA revealed transcriptional regulation by the vitamin D receptor. Simultaneously, hyperphosphorylated pRb was transformed to the hypophosphorylated form. Our results demonstrate that the biologically active form of vitamin D3 directly regulates the expression of p21 and p27, inducing a G0/G1 phase arrest: one mechanism by which 1,25(OH)2D3 controls cell proliferation in SCCHN.

Circulating tumor cells in metastatic colorectal cancer: Efficacy and feasibility of different enrichment methods

Comprehensive in vitro and in vivo studies comparing EpCAM-based methods with other cytometric CTC enrichment technologies in metastatic colorectal cancer (mCRC) patients are lacking. We compare four manual cytometric methods to detect CTCs in vitro and in mCRC patients. The EpCAM-based technology, MACS HEA MicroBeads((R)), showed a significant better tumor cell recovery rate compared to other cytometric methods (p-value<0.0001). CTCs of 38 mCRC patients were enriched with MACS HEA MicroBeads(R). Progression-free survival did significantly differ between mCRC patients without detectable and with >or= 1 CTCs (p=0.007). CTC enrichment with EpCAM coupled antibodies is superior to other cytometric methods and is a feasible method for CTC detection in mCRC patients.

Validating the impact of a molecular subtype in ovarian cancer on outcomes: A study of the OVCAD Consortium

Most patients with epithelial ovarian cancer (EOC) are diagnosed at advanced stage and have a poor prognosis. However, a small proportion of these patients will survive, whereas others will die very quickly. Clinicopathological factors do not allow precise identification of these subgroups. Thus, we have validated a molecular subclassification as new prognostic factor in EOC. One hundred and ninety‐four patients with Stage II–IV EOC were characterized by whole‐genome expression profiling of tumor tissues and were classified using a published 112 gene set, derived from an International Federation of Gynecology and Obstetrics (FIGO) stage‐directed supervised classification approach. The 194 tumor samples were classified into two subclasses comprising 95 (Subclass 1) and 99 (Subclass 2) tumors. All nine FIGO II tumors were grouped in Subclass 1 (P = 0.001). Subclass 2 (54% of advanced‐stage tumors) was significantly correlated with peritoneal carcinomatosis and non‐optimal debulking. Patients with Subclass 2 tumors had a worse overall survival for both serous and non‐serous histological subtypes, as revealed by univariate analysis (hazard ratios [HR] of 3.17 and 17.11, respectively; P ≤ 0.001) and in models corrected for relevant clinicopathologic parameters (HR 2.87 and 12.42, respectively; P ≤ 0.023). Significance analysis of microarrays revealed 2082 genes that were differentially expressed in advanced‐grade serous tumors of both subclasses and the focal adhesion pathway as the most deregulated pathway. In the present validation study, we have shown that, in advanced‐stage serous ovarian cancer, two approximately equally large molecular subtypes exist, independent of classical clinocopathological parameters and presenting with highly different whole‐genome expression profiles and a markedly different overall survival. Similar results were obtained in a small cohort of patients with non‐serous tumors. (Cancer Sci 2012; 103: 1334–1341)

Δ133p53 is an independent prognostic marker in p53 mutant advanced serous ovarian cancer

Background:We aimed to evaluate the clinical relevance of p53 and p73 isoforms that modulate the function of p53.Methods:This prospective multicentre study included 154 patients with stage III and IV serous ovarian cancer. A functional yeast-based assay and subsequent sequencing were performed to analyse the p53 mutational status. Expression of p53 and p73 isoforms was determined using RT–qPCR.Results:Δ133p53 expression constituted an independent prognostic marker for recurrence-free (hazard ratio=0.571, P=0.016, 95% CI: 0.362–0.899) and overall survival (hazard ratio=0.365, P=0.004, 95% CI: 0.182–0.731) in patients with p53 mutant ovarian cancer (n=121). High Δ40p53 expression was associated with favourable tumour grading (P=0.037) and improved recurrence-free survival (33.4 vs 19.6 months, P=0.029), but not overall survival (43.1 vs 33.6 months, P=0.139), in patients with p53 wild-type cancer (n=33). Neither the p53 mutational status nor p73 isoform expression possessed prognostic significance in the examined ovarian cancer cases.Conclusion:Δ133p53 expression was associated with prognosis in the vast majority of ovarian cancer cases, that is, patients with p53 mutant advanced serous carcinomas. Thus, our findings underline the importance of considering the complex p53 regulatory network.

Cyclin E1 (CCNE1) as independent positive prognostic factor in advanced stage serous ovarian cancer patients - A study of the OVCAD consortium

Cyclin E, coded by the genes CCNE1 and CCNE2, is the main regulator for transition from G1 to S phase determining cell division. CCNE1 and CCNE2 are known oncogenes in many cancer entities. Especially CCNE1 has frequently been associated with gene amplifications in various malignancies, emphasising its role as a putative oncogene. We determined gene expression and copy number of CCNE1 and CCNE2 by quantitative polymerase chain reaction (PCR) from 172 International Federation of Obstetrics and Gynecology (FIGO) II/III/IV stage serous epithelial ovarian cancer (EOC) tissues and analysed its impact on outcome. Furthermore, whole transcriptome gene expression changes correlating with CCNE1 expression were determined by microarray technology, interpreted by Signalling Pathway Impact Analysis (SPIA), Tool for Inferring Network of Genes (TINGe), and illustrated by hive plots. Protein-protein interaction (PPI) networks were also used for the interpretation. Interestingly, and contradictory to most reports and intuitive expectations, high CCNE1 expression correlated with better overall survival (p=0.005) if corrected for usual clinicopathologic parameters and a molecular subclassification. Using different grading systems or only high graded tumours had no impact on this correlation. Copy number of CCNE1 was increased in 25% of cases which correlated highly significantly with expression but showed no impact on outcome. CCNE2 had no impact on outcomes at all. Whole genome transcriptome analysis revealed 1872 differentially expressed genes correlated to CCNE1 expression, which were significantly enriched with genes from five pathways (e.g. cell cycle and viral carcinogenesis pathway were up-regulated and the Fanconi anaemia pathway was down-regulated). High CCNE1 gene expression is a significant and independent predictor for prolonged overall survival in FIGO III/IV EOC patients. This upside down impact of CCNE1 on survival probably reflects the special characteristic of EOC with tumour dissemination in the near anaerobic peritoneal cavity as the predominant cause of death, compared to other cancer entities where distant metastasis are predominantly lethal.

A combined blood based gene expression and plasma protein abundance signature for diagnosis of epithelial ovarian cancer - a study of the OVCAD consortium

BackgroundThe immune system is a key player in fighting cancer. Thus, we sought to identify a molecular ‘immune response signature’ indicating the presence of epithelial ovarian cancer (EOC) and to combine this with a serum protein biomarker panel to increase the specificity and sensitivity for earlier detection of EOC.MethodsComparing the expression of 32,000 genes in a leukocytes fraction from 44 EOC patients and 19 controls, three uncorrelated shrunken centroid models were selected, comprised of 7, 14, and 6 genes. A second selection step using RT-qPCR data and significance analysis of microarrays yielded 13 genes (AP2A1, B4GALT1, C1orf63, CCR2, CFP, DIS3, NEAT1, NOXA1, OSM, PAPOLG, PRIC285, ZNF419, and BC037918) which were finally used in 343 samples (90 healthy, six cystadenoma, eight low malignant potential tumor, 19 FIGO I/II, and 220 FIGO III/IV EOC patients). Using new 65 controls and 224 EOC patients (thereof 14 FIGO I/II) the abundances of six plasma proteins (MIF, prolactin, CA125, leptin, osteopondin, and IGF2) was determined and used in combination with the expression values from the 13 genes for diagnosis of EOC.ResultsCombined diagnostic models using either each five gene expression and plasma protein abundance values or 13 gene expression and six plasma protein abundance values can discriminate controls from patients with EOC with Receiver Operator Characteristics Area Under the Curve values of 0.998 and bootstrap .632+ validated classification errors of 3.1% and 2.8%, respectively. The sensitivities were 97.8% and 95.6%, respectively, at a set specificity of 99.6%.ConclusionsThe combination of gene expression and plasma protein based blood derived biomarkers in one diagnostic model increases the sensitivity and the specificity significantly. Such a diagnostic test may allow earlier diagnosis of epithelial ovarian cancer.

AID/APOBEC-network reconstruction identifies pathways associated with survival in ovarian cancer

BackgroundBuilding up of pathway-/disease-relevant signatures provides a persuasive tool for understanding the functional relevance of gene alterations and gene network associations in multifactorial human diseases. Ovarian cancer is a highly complex heterogeneous malignancy in respect of tumor anatomy, tumor microenvironment including pro-/antitumor immunity and inflammation; still, it is generally treated as single disease. Thus, further approaches to investigate novel aspects of ovarian cancer pathogenesis aiming to provide a personalized strategy to clinical decision making are of high priority. Herein we assessed the contribution of the AID/APOBEC family and their associated genes given the remarkable ability of AID and APOBECs to edit DNA/RNA, and as such, providing tools for genetic and epigenetic alterations potentially leading to reprogramming of tumor cells, stroma and immune cells.ResultsWe structured the study by three consecutive analytical modules, which include the multigene-based expression profiling in a cohort of patients with primary serous ovarian cancer using a self-created AID/APOBEC-associated gene signature, building up of multivariable survival models with high predictive accuracy and nomination of top-ranked candidate/target genes according to their prognostic impact, and systems biology-based reconstruction of the AID/APOBEC-driven disease-relevant mechanisms using transcriptomics data from ovarian cancer samples. We demonstrated that inclusion of the AID/APOBEC signature-based variables significantly improves the clinicopathological variables-based survival prognostication allowing significant patient stratification. Furthermore, several of the profiling-derived variables such as ID3, PTPRC/CD45, AID, APOBEC3G, and ID2 exceed the prognostic impact of some clinicopathological variables. We next extended the signature-/modeling-based knowledge by extracting top genes co-regulated with target molecules in ovarian cancer tissues and dissected potential networks/pathways/regulators contributing to pathomechanisms. We thereby revealed that the AID/APOBEC-related network in ovarian cancer is particularly associated with remodeling/fibrotic pathways, altered immune response, and autoimmune disorders with inflammatory background.ConclusionsThe herein study is, to our knowledge, the first one linking expression of entire AID/APOBECs and interacting genes with clinical outcome with respect to survival of cancer patients. Overall, data propose a novel AID/APOBEC-derived survival model for patient risk assessment and reconstitute mapping to molecular pathways. The established study algorithm can be applied further for any biologically relevant signature and any type of diseased tissue.