[Show abstract][Hide abstract] ABSTRACT: Using patient-derived xenografts (PDXs) for preclinical cancer research demands proper storage of tumour material to facilitate logistics and to reduce the number of animals needed. We successfully established 45 subcutaneous ovarian cancer PDXs, reflecting all histological subtypes, with an overall take rate of 68%. Corresponding cells from mouse replaced human tumour stromal and endothelial cells in second generation PDXs as demonstrated with mouse-specific vimentin and CD31 immunohistochemical staining. For biobanking purposes two cryopreservation methods, a fetal calf serum (FCS)-based (95%v/v) " FCS/DMSO " protocol and a low serum-based (10%v/v) " vitrification " protocol were tested. After primary cryopreservation, tumour take rates were 38% and 67% using either the vitrification or FCS/DMSO-based cryopreservation protocol, respectively. Cryopreserved tumour tissue of established PDXs achieved take rates of 67% and 94%, respectively compared to 91% using fresh PDX tumour tissue. Genotyping analysis showed that no changes in copy number alterations were introduced by any of the biobanking methods. Our results indicate that both protocols can be used for biobanking of ovarian tumour and PDX tissues. However, FCS/DMSO-based cryopreservation is more successful. Moreover, primary engraftment of fresh patient-derived tumours in mice followed by freezing tissue of successfully established PDXs is the preferred way of efficient ovarian cancer PDX biobanking.
[Show abstract][Hide abstract] ABSTRACT: Background:
Understanding carboplatin resistance in ovarian cancer is critical for the improvement of patients' lives. Multipotent mesenchymal stem cells or an aggravated epithelial to mesenchymal transition phenotype of a cancer are integrally involved in pathways conferring chemo-resistance. Long non-coding RNA HOTAIR (HOX transcript antisense intergenic RNA) is involved in mesenchymal stem cell fate and cancer biology.
We analyzed HOTAIR expression and associated surrogate DNA methylation (DNAme) in 134 primary ovarian cancer cases (63 received carboplatin, 55 received cisplatin and 16 no chemotherapy). We validated our findings by HOTAIR expression and DNAme analysis in a multicentre setting of five additional sets, encompassing 946 ovarian cancers. Chemo-sensitivity has been assessed in cell culture experiments.
HOTAIR expression was significantly associated with poor survival in carboplatin-treated patients with adjusted hazard ratios for death of 3.64 (95 % confidence interval [CI] 1.78-7.42; P < 0.001) in the discovery and 1.63 (95 % CI 1.04-2.56; P = 0.032) in the validation set. This effect was not seen in patients who did not receive carboplatin (0.97 [95 % CI 0.52-1.80; P = 0.932]). HOTAIR expression or its surrogate DNAme signature predicted poor outcome in all additional sets of carboplatin-treated ovarian cancer patients while HOTAIR expressors responded preferentially to cisplatin (multivariate interaction P = 0.008).
Non-coding RNA HOTAIR or its more stable DNAme surrogate may indicate the presence of a subset of cells which confer resistance to carboplatin and can serve as (1) a marker to personalise treatment and (2) a novel target to overcome carboplatin resistance.
Genome Medicine 10/2015; 7(1):108. DOI:10.1186/s13073-015-0233-4 · 5.34 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Aims:
Tumor-specific targeted imaging is rapidly evolving in cancer diagnosis. The folate receptor alpha (FR-α) has already been identified as a suitable target for cancer therapy and imaging. FR-α is present on ~40% of human cancers. FR-β is known to be expressed on several hematologic malignancies and on activated macrophages, but little is known about FR-β expression in solid tumors. Additional or simultaneous expression of FR-β could help extend the indications for folate-based drugs and imaging agents. In this study, the expression pattern of FR-β is evaluated in ovarian, breast and colorectal cancer.
FR-β expression was analyzed by semi-quantitative scoring of immunohistochemical staining on tissue microarrays (TMAs) of 339 ovarian cancer patients, 418 breast cancer patients, on 20 slides of colorectal cancer samples and on 25 samples of diverticulitis.
FR-β expression was seen in 21% of ovarian cancer samples, 9% of breast cancer samples, and 55% of colorectal cancer samples. Expression was weak or moderate. Of the diverticulitis samples, 80% were positive for FR-β expression in macrophages. FR-β status neither correlated to known disease-related variables, nor showed association with overall survival and progression free survival in ovarian and breast cancer. In breast cancer, negative axillary status was significantly correlated to FR-β expression (p=0.022).
FR-β expression was low or absent in the majority of ovarian, breast and colorectal tumor samples. From the present study we conclude that the low FR-β expression in ovarian and breast tumor tissue indicates limited practical use of this receptor in diagnostic imaging and therapeutic purposes. Due to weak expression, FR-β is not regarded as a suitable target in colorectal cancer.
PLoS ONE 08/2015; 10(8):e0135012. DOI:10.1371/journal.pone.0135012 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The first version of ENGOT's Requirements for Trials Between Academic Groups and Industry Partners in Europe was published 2010. This first update integrates the experiences made by the ENGOT network and the cooperative group studies while performing, analyzing, and publishing -among others - three large phase III trials. Furthermore, progress in European legislation and its impact on clinical studies in Europe have been considered in this update process.
International Journal of Gynecological Cancer 06/2015; 25(7). DOI:10.1097/IGC.0000000000000478 · 1.96 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Epigenetic silencing of tumor suppressor genes (TSGs) is considered a significant event in the progression of cancer. For example, EPB41L3, a potential biomarker in cervical cancer, is often silenced by cancer-specific promoter methylation. Artificial transcription factors (ATFs) are unique tools to re-express such silenced TSGs to functional levels; however, the induced effects are considered transient. Here, we aimed to improve the efficiency and sustainability of gene re-expression using engineered zinc fingers fused to VP64 (ZF-ATFs) or DNA methylation modifiers (ZF-Tet2 or ZF-TDG) and/or by co-treatment with epigenetic drugs [5-aza-dC2'-deoxycytidine or Trichostatin A (TSA)]. EPB41L3-ZF effectively bound its methylated endogenous locus, as also confirmed by ChIP-seq. ZF-ATFs reactivated the epigenetically silenced target gene EPB41L3 (˜10-fold) in breast, ovarian, and cervical cancer cell lines. Prolonged high levels of EPB41L3 (˜150-fold) induction could be achieved by short-term co-treatment with epigenetic drugs. Interestingly, for otherwise ineffective ZF-Tet2 or ZF-TDG treatments, TSA facilitated re-expression of EPB41L3 by up to twofold. ATF-mediated re-expression demonstrated a tumor suppressive role for EPB41L3 in cervical cancer cell lines. In conclusion, epigenetic reprogramming provides a novel way to improve sustainability of re-expression of epigenetically silenced promoters.
Epigenetics: official journal of the DNA Methylation Society 04/2015; 10(5). DOI:10.1080/15592294.2015.1034415 · 4.78 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study demonstrates that both the clinical sensitivity and specificity of the Cervista HPV HR test for high-risk human
papillomavirus (HPV) detection are not inferior to those of the Hybrid Capture 2 (HC2) test. The intra- and interlaboratory
reproducibilities of Cervista were 92.0% (kappa, 0.83) and 90.4% (kappa, 0.80), respectively. The Cervista HPV HR test fulfills
all the international HPV test requirements for cervical primary screening purposes.
[Show abstract][Hide abstract] ABSTRACT: The diagnostic performance of the widely-used Cervista HPV HR test was compared to the Hybrid Capture 2 (HC2) test in a Dutch population-based cervical cancer screening program. In 900 scrapings of women with normal cytomorphology, specificity was 90% (95%CI: 87.84-91.87) for the Cervista HPV HR test and 96% (95%CI: 94.76-97.37) for the HC2 test with 93% agreement between both tests (κ = 0.5, p<0.001). The sensitivity for CIN2+ using 65 scrapings of women with histological-confirmed CIN2+ was 91% (95%CI: 80.97-96.51) for the Cervista HPV HR test and 92% (95%CI: 82.94-97.43) for the HC2 test with 95% agreement between both tests (κ = 0.7, p<0.001). Fifty-seven of 60 HC2 negative/Cervista positive cases tested HPV-negative with PCR-based HPV assays; of these cases 56% were defined as Cervista triple-positive with FOZ values in all 3 mixes higher than the second cut-off of 1.93 (as set by manufacturer). By setting this cut-off at 5.0, specificity improved significantly without affecting sensitivity. External validation of this new cut-off at 5.0 in triple-positive scrapings of women selected from the SHENCCASTII database revealed that 22/24 histological normal cases now tested HPV-negative in the Cervista HPV HR test, while CIN2+ lesions remained HPV-positive. The intra-laboratory reproducibility of the Cervista HPV HR test (n = 510) showed a concordance of 92% and 93% for cut-off 1.93 and 5.0 (κ = 0.83 and κ = 0.84, p<0.001) and inter-laboratory agreement of the Cervista HPV HR test was 90% and 93% for cut-off 1.93 and 5.0 (κ = 0.80 and κ = 0.85, p<0.001). In conclusion, the specificity of the Cervista HPV HR test could be improved significantly by increasing the second cut-off from 1.93 to 5.0, without affecting the sensitivity of the test in a population-based screening setting.
PLoS ONE 07/2014; 9(7):e101930. DOI:10.1371/journal.pone.0101930 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective:
The aim of this study was to determine possible impact of routinely scheduled biopsies and more radical surgery for residual central disease in locally advanced cervical cancer after (chemo)radiation.
Data were analyzed of a consecutive series of cervical cancer patients (The International Federation of Gynecology and Obstetrics stages IB1-IVA) treated with (chemo) radiation between 1994 and 2011. Patients underwent gynecologic examination with biopsies 8 to 10 weeks after treatment. Since 2001, larger biopsies by electric loop excision were taken, and more radical surgery (type III hysterectomy or exenteration) was performed for central residual disease. Primary outcome was locoregional recurrence. Secondary outcomes were treatment-associated morbidity and disease-specific survival.
Primary (chemo)radiation was given to 491 cervical cancer patients; 345 patients had a posttreatment biopsy. Viable tumor cells were identified in 84 patients, and 61 patients were eligible for salvage surgery. Residual disease after (chemo)radiation was an independent poor prognostic factor (hazard ratio, 3.59; 95% confidence interval, 2.18-5.93; P < 0.001). After 2001, larger biopsies were more frequently taken (29% vs 76%, P < 0.001), and in patients without viable tumor cells, locoregional recurrence after 2001 decreased from 21% to 10% (P = 0.01). After 2001, more patients underwent more radical surgery (46% vs 90%) (P < 0.001). Locoregional recurrence after surgery before 2001 occurred in 6 (46%) of the 13 patients, comparable with 19 (40%) of the 48 (P = 0.67) after 2001. More radical surgery was not associated with improved disease-specific survival (HR, 0.84; 95% CI, 0.20-3.46; P = 0.81) but did result in significantly more severe morbidity.
More radical surgery in patients with (minimal) central residual disease identified by routine biopsy 8 to 10 weeks after (chemo)radiation does not improve survival and should not be recommended.
International Journal of Gynecological Cancer 07/2014; 24(7). DOI:10.1097/IGC.0000000000000171 · 1.96 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To elucidate the role of biological and clinical impact of aberrant promoter hypermethylation (PH) in ovarian cancer (OC).
PH of PGP9.5, HIC1, AIM1, APC, PAK3, MGMT, KIF1A, CCNA1, ESR1, SSBP2, GSTP1, FKBP4 and VGF were assessed by quantitative methylation specific PCR (QMSP) in a training set. We selected two genes (VGF and PGP9.5) for further QMSP analysis in a larger independent validation (IV) set with available clinical data. Biologic relevance of VGF gene was also evaluated.
PH frequency for PGP9.5 and VGF were 85% (316/372) and 43% (158/366) respectively in the IV set of samples while no PH was observed in controls. In 372 OC cases with available follow up, PGP9.5 and VGF PH were correlated with better patient survival [Hazard Ratios (HR) for overall survival (OS) were 0.59 (95% Confidence Intervals (CI) = 0.42-0.84, p = 0.004), and 0.73 (95%CI = 0.55-0.97, p = 0.028) respectively, and for disease specific survival (DSS) were 0.57 (95%CI 0.39-0.82, p = 0.003) and 0.72 (95%CI 0.54-0.96, p = 0.027). In multivariate analysis, VGF PH remained an independent prognostic factor for OS (HR 0.61, 95%CI 0.43-0.86, p<0.005) and DSS (HR 0.58, 95%CI 0.41-0.83, p<0.003). Furthermore, PGP9.5 PH was significantly correlated with lower grade, early stage tumors, and with absence of residual disease. Forced expression of VGF in OC cell lines inhibited cell growth.
Our results indicate that VGF and PGP9.5 PH are potential biomarkers for ovarian carcinoma. Confirmatory cohorts with longitudinal follow-up are required in future studies to define the clinical impact of VGF and PGP9.5 PH before clinical application.
PLoS ONE 10/2013; 8(9):e70878. DOI:10.1371/journal.pone.0070878 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective:
The purpose of this study was to assess the prevalence of underlying bleeding disorders in women with heavy menstrual bleeding (HMB) with and without gynecologic abnormalities.
We performed a single-center prospective cohort study of 112 consecutive patients who were referred for heavy menstrual bleeding. Control subjects were 28 healthy volunteers who reported no HMB. Patients and control subjects had hemostatic testing in the first week after menstruation. Patients underwent gynecologic evaluation.
The median age was 42.5 years (range, 17-55 years) in patients and 40.0 years (range, 25-55 years) in control subjects. Forty-six percent of patients had anemia; the median pictorial bleeding assessment chart score was 271. Seven percent of the control subjects with a subjectively normal menstruation had anemia. Twenty-six percent of patients had gynecologic abnormalities, which was considered to explain HMB. Overall, we found an underlying bleeding disorder in 29% of the patients, which was comparable for unexplained and explained HMB (31% vs 27%; P = .75). We diagnosed 6 cases of Von Willebrand's disease, 4 cases of factor XI deficiency, and 1 case of factor VII deficiency. The only abnormalities that we found in control subjects were platelet aggregation defects (11% in control subjects vs 23% in patients). Patients had a significantly longer activated partial thromboplastin time compared with control subjects (26.5 vs 25.0 seconds; P = .001) that was caused by lower median levels of factor XI (100 vs 124 IU/dL; P < .001).
Bleeding disorders play an equally important role in the cause of both unexplained and explained heavy menstrual bleeding. A novel finding is the occurrence of low, but not deficient, levels of factor XI.
American journal of obstetrics and gynecology 05/2013; 209(3). DOI:10.1016/j.ajog.2013.05.059 · 4.70 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: C13ORF18 is frequently hypermethylated in cervical cancer but not in normal cervix and might serve as a biomarker for the early detection of cervical cancer in scrapings. As hypermethylation is often observed for silenced tumor suppressor genes (TSGs), hypermethylated biomarker genes might exhibit tumor suppressive activities upon re-expression. Epigenetic drugs are successfully exploited to reverse TSG silencing, but act genome-wide. Artificial Transcription Factors (ATFs) provide a gene-specific approach for re-expression of silenced genes. Here, we investigated the potential tumor suppressive role of C13ORF18 in cervical cancer by ATF-induced re-expression. Five zinc finger proteins were engineered to bind the C13ORF18 promoter and fused to a strong transcriptional activator. C13ORF18 expression could be induced in cervical cell lines: ranging from >40-fold in positive (C13ORF18-unmethylated) cells to >110-fold in negative (C13ORF18-methylated) cells. Re-activation of C13ORF18 resulted in significant cell growth inhibition and/or induction of apoptosis. Co-treatment of cell lines with ATFs and epigenetic drugs further enhanced the ATF-induced effects. Interestingly, re-activation of C13ORF18 led to partial demethylation of the C13ORF18 promoter and decreased repressive histone methylation. These data demonstrate the potency of ATFs to re-express and potentially demethylate hypermethylated silenced genes. Concluding, we show that C13ORF18 has a TSG function in cervical cancer and may serve as a therapeutic anti-cancer target. As the amount of epimutations in cancer exceeds the number of gene mutations, ATFs provide promising tools to validate hypermethylated marker genes as therapeutic targets.
[Show abstract][Hide abstract] ABSTRACT: Macroporous reversed-phase (mRP) chromatography was successfully used to develop an accurate and precise method for total protein in serum. The limits of detection (0.83 μg, LOD) and quantification (2.51 μg, LOQ) for the mRP method are comparable with those of the widely used micro BCA protein assay. The mRP method can be used to determine the total protein concentration across a wide dynamic range by detecting chromatographic peaks at 215 nm and 280 nm. The method has the added advantage of desalting and denaturing proteins, leading to more complete digestion by trypsin and to better LC–MS–MS identification in shotgun proteomics experiments.
Simultaneous Serum Desalting and Total Protein Determination with Macroporous Reversed-Phase Chromatography: calibration plots
[Show abstract][Hide abstract] ABSTRACT: Treatment of advanced-stage cervical cancers with (chemo)radiation causes cytotoxicity through induction of high levels of DNA damage. Tumour cells respond to DNA damage by activation of the 'DNA damage response' (DDR), which induces DNA repair and may counteract chemoradiation efficacy. Here, we investigated DDR components as potential therapeutic targets and verified the predictive and prognostic value of DDR activation in patients with cervical cancer treated with (chemo)radiation. In a panel of cervical cancer cell lines, inactivation of ataxia telangiectasia mutated (ATM) or its substrate p53-binding protein-1 (53BP1) clearly gave rise to cell cycle defects in response to irradiation. Concordantly, clonogenic survival analysis revealed that ATM inhibition, but not 53BP1 depletion, strongly radiosensitised cervical cancer cells. In contrast, ATM inhibition did not radiosensitise non-transformed epithelial cells or non-transformed BJ fibroblasts. Interestingly, high levels of active ATM prior to irradiation were related with increased radioresistance. To test whether active ATM in tumours prior to treatment also resulted in resistance to therapy, immunohistochemistry was performed on tumour material of patients with advanced-stage cervical cancer (n = 375) treated with (chemo)radiation. High levels of phosphorylated (p-)ATM [p = 0.006, hazard ratio (HR) = 1.817] were related to poor locoregional disease-free survival. Furthermore, high levels of p-ATM predicted shorter disease-specific survival (p = 0.038, HR = 1.418). The presence of phosphorylated 53BP1 was associated with p-ATM (p = 0.001, odds ratio = 2.206) but was not related to any clinicopathological features or survival. In conclusion, both our in vitro and patient-related findings indicate a protective role for ATM in response to (chemo)radiation in cervical cancer and point at ATM inhibition as a possible means to improve the efficacy of (chemo)radiation.
International Journal of Cancer 11/2012; 131(9):2056-66. DOI:10.1002/ijc.27488 · 5.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Epigenetic modifications, such as aberrant DNA promoter methylation, are frequently observed in cervical cancer. Identification of hypermethylated regions allowing discrimination between normal cervical epithelium and high-grade cervical intraepithelial neoplasia (CIN2/3), or worse, may improve current cervical cancer population-based screening programs. In this study, the DNA methylome of high-grade CIN lesions was studied using genome-wide DNA methylation screening to identify potential biomarkers for early diagnosis of cervical neoplasia. Methylated DNA Immunoprecipitation (MeDIP) combined with DNA microarray was used to compare DNA methylation profiles of epithelial cells derived from high-grade CIN lesions with normal cervical epithelium. Hypermethylated differentially methylated regions (DMRs) were identified. Validation of nine selected DMRs using BSP and MSP in cervical tissue revealed methylation in 63.2-94.7% high-grade CIN and in 59.3-100% cervical carcinomas. QMSP for the two most significant high-grade CIN-specific methylation markers was conducted exploring test performance in a large series of cervical scrapings. Frequency and relative level of methylation were significantly different between normal and cancer samples. Clinical validation of both markers in cervical scrapings from patients with an abnormal cervical smear confirmed that frequency and relative level of methylation were related with increasing severity of the underlying CIN lesion and that ROC analysis was discriminative. These markers represent the COL25A1 and KATNAL2 and their observed increased methylation upon progression could intimate the regulatory role in carcinogenesis. In conclusion, our newly identified hypermethylated DMRs represent specific DNA methylation patterns in high-grade CIN lesions and are candidate biomarkers for early detection. "
Epigenetics: official journal of the DNA Methylation Society 09/2012; 7(11). DOI:10.4161/epi.22301 · 4.78 Impact Factor