Publications by authors named "Burkhard Brandt"

76 Publications

Longitudinal Multi-omics Analyses Identify Responses of Megakaryocytes, Erythroid Cells, and Plasmablasts as Hallmarks of Severe COVID-19.

Immunity 2020 12 26;53(6):1296-1314.e9. Epub 2020 Nov 26.

Institute of Clinical Molecular Biology, Kiel University and University Medical Center Schleswig-Holstein, 24105 Kiel, Germany. Electronic address:

Temporal resolution of cellular features associated with a severe COVID-19 disease trajectory is needed for understanding skewed immune responses and defining predictors of outcome. Here, we performed a longitudinal multi-omics study using a two-center cohort of 14 patients. We analyzed the bulk transcriptome, bulk DNA methylome, and single-cell transcriptome (>358,000 cells, including BCR profiles) of peripheral blood samples harvested from up to 5 time points. Validation was performed in two independent cohorts of COVID-19 patients. Severe COVID-19 was characterized by an increase of proliferating, metabolically hyperactive plasmablasts. Coinciding with critical illness, we also identified an expansion of interferon-activated circulating megakaryocytes and increased erythropoiesis with features of hypoxic signaling. Megakaryocyte- and erythroid-cell-derived co-expression modules were predictive of fatal disease outcome. The study demonstrates broad cellular effects of SARS-CoV-2 infection beyond adaptive immune cells and provides an entry point toward developing biomarkers and targeted treatments of patients with COVID-19.
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http://dx.doi.org/10.1016/j.immuni.2020.11.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7689306PMC
December 2020

Isolation and Enumeration of CTC in Colorectal Cancer Patients: Introduction of a Novel Cell Imaging Approach and Comparison to Cellular and Molecular Detection Techniques.

Cancers (Basel) 2020 Sep 16;12(9). Epub 2020 Sep 16.

Institute for Experimental Cancer Research, Kiel University and University Hospital Schleswig-Holstein Campus Kiel, Arnold-Heller-Str. 3, Building U30 Entrance 1, 24105 Kiel, Germany.

Circulating tumour cells (CTC) were proven to be prognostically relevant in cancer treatment, e.g., in colorectal cancer (CRC). This study validates a molecular detection technique through using a novel cell imaging approach for CTC detection and enumeration, in comparison to a size-based cellular and correlated the data to clinico-pathological characteristics. Overall, 57 CRC patients were recruited for this prospective study. Blood samples were analysed for CTCs by three methods: (1) Epithelial marker immunofluorescence staining combined with automated microscopy using the NYONE cell imager; (2) isolation by size using membrane filtration with the ScreenCell Cyto IS device and immunofluorescence staining; (3) detection by semi-quantitative Cytokeratin-20 RT-qPCR. Enumeration data were compared and correlated with clinic-pathological parameters. CTC were detected by either approach; however, with varying positivity rates: NYONE 36.4%, ScreenCell 100%, and PCR 80.5%. All methods revealed a positive correlation of CTC presence and higher tumour burden, which was most striking using the ScreenCell device. Generally, no intercorrelation of CTC presence emerged amongst the applied techniques. Overall, enumeration of CTC after isolation by size demonstrated to be the most reliable strategy for the detection of CTC in CRC patients. Ongoing studies will have to unravel the prognostic value of this finding, and validate this approach in a larger cohort.
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http://dx.doi.org/10.3390/cancers12092643DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7563529PMC
September 2020

EGFR as a stable marker of prostate cancer dissemination to bones.

Br J Cancer 2020 Dec 9;123(12):1767-1774. Epub 2020 Sep 9.

Laboratory of Translational Oncology, Institute of Medical Biotechnology and Experimental Oncology, Medical University of Gdańsk, Gdańsk, Poland.

Background: Prostate cancer (PCa) is among the most commonly diagnosed malignancies in men. Although 5-year survival in patients with localised disease reaches nearly 100%, metastatic disease still remains incurable. Therefore, there is a need for markers indicating metastatic dissemination.

Methods: EGFR overexpression (EGFR) was tracked in 1039 primary tumours, circulating tumour cells from 39 d'Amico high-risk patients and metastatic samples from 21 castration-resistant PCa cases. EGFR status was compared to clinical parameters and multiple molecular factors were assessed using immunohistochemistry and gene ontology analysis. The functional aspect of EGFR was evaluated by plating PC-3 cells on soft and rigid matrices.

Results: EGFR was found in 14% of primary tumours, where it was associated with shorter metastasis-free survival and was an independent indicator of worse overall survival. EGFR correlated with a pro-migratory and pro-metastatic phenotype of tumour cells as well as rich collagen fibre content. All circulating tumour cells (detected in 13% of cases) were positive for EGFR, independent of their EMT-related phenotype. EGFR was more prevalent in castration-resistant bone metastases (29% of patients) and supported growth of human PCa cells on rigid matrices mimicking bone stiffness.

Conclusions: EGFR is a stable, EMT-independent marker of PCa disseminating to rigid organs, preferentially bones.
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http://dx.doi.org/10.1038/s41416-020-01052-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7722745PMC
December 2020

RE: Oral Leukoplakia and Risk of Progression to Oral Cancer: A Population-Based Cohort Study.

J Natl Cancer Inst 2020 Sep;112(9):968-969

Klinik für Mund, -Kiefer- und Gesichtschirurgie, Marienhospital Stuttgart, Stuttgart, Germany.

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http://dx.doi.org/10.1093/jnci/djaa074DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7492755PMC
September 2020

Low Numbers of Vascular Vessels Correlate to Progression in Hormone-Naïve Prostate Carcinomas Undergoing Radical Prostatectomy.

Cancers (Basel) 2019 Sep 12;11(9). Epub 2019 Sep 12.

Laboratory of Cell Biology, Department of Medical Biotechnology, Medical University of Gdańsk, Gdańsk 80-211, Poland.

Vascularization influences tumor development by supporting the nutrition and dissemination of tumor cells. On the other hand, a low number of vascular vessels (VV) may induce hypoxia, accounting for selection of resistant clone(s) of tumor cells. This study aimed to evaluate the prognostic significance of vascular (VV) and lymphatic vessels (LV) in prostate cancer (PCa). Tumor samples from 400 PCa patients undergoing radical prostatectomy (RP) were prepared in duplex as tissue microarrays. Numbers of VV and LV were evaluated using immunohistochemistry detecting CD34 and podoplanin, respectively, and correlated to clinical data, biochemical recurrence (BR), and proteins analyzed in tumor cells. VV and LV were found in 32% and 43% of patients with informative PCa samples, respectively. VV correlated with a shorter time to BR 3, 5, and 10 years after RP in hormone-naïve patients ( = 0.028, = 0.027 and = 0.056, respectively). It was also shown to be an independent prognostic factor 5 years after surgery (multivariate analysis, = 0.046). Tumors characterized by VV expressed the epithelial cell adhesion molecule, EpCAM, less frequently ( = 0.016) and revealed a borderline correlation to increased levels of tumor cell invasion marker Loxl-2 ( = 0.059). No correlations were found for LV. In summary, VV in hormone-naïve patients undergoing RP has prognostic potential and seems to be related to an aggressive phenotype of tumor cells.
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http://dx.doi.org/10.3390/cancers11091356DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6770894PMC
September 2019

BRCAness in prostate cancer.

Oncotarget 2019 Mar 29;10(25):2421-2422. Epub 2019 Mar 29.

Natalia Bednarz-Knoll: Laboratory of Cell Biology, Department of Medical Biotechnology, Medical University of Gdańsk, Gdańsk, Poland.

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http://dx.doi.org/10.18632/oncotarget.26818DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6497433PMC
March 2019

ALDH1-positive intratumoral stromal cells indicate differentiated epithelial-like phenotype and good prognosis in prostate cancer.

Transl Res 2019 01 12;203:49-56. Epub 2018 Sep 12.

Department of Tumour Biology, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany; Laboratory of Cell Biology, Department of Medical Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland. Electronic address:

Aldehyde dehydrogenase 1 (ALDH1) characterizes tumor-initiating cells in solid tumors; however, little is known about its expression in intratumoral stromal cells. Herein, we aimed to dissect its potential dual relevance in prostate cancer (PCa). ALDH1 expression was evaluated immunohistochemically in tumor and stromal cells in primary PCa and metastases. It was correlated to clinico-pathologic parameters, patients' outcome, and selected proteins (CK5/6, CK14, CK8/18, CK19, EpCAM, Ki-67, E-cadherin, N-cadherin, and vimentin). ALDH1 protein was detected in tumor and stromal cells in 16% and 67% of 348 primary PCa, respectively. Tumor cell ALDH1 expression was associated with advanced T stage (P = 0.009), higher Gleason score (P = 0.016), shorter time to biochemical recurrence (TBR P = 0.010) and CK14 expression (P = 0.023). Stromal cell ALDH1 expression correlated to lower T stage (P = 0.008) and Gleason score (P = 0.016), N0 stage (P = 0.017), and longer TBR (P = 0.017). It occurred to be an independent predictor of good prognosis in the subgroup of d'Amico high-risk patients (multivariate analysis, P = 0.050). ALDH1-positive stromal cells were found in tumors characterized frequently by CK8/18 (P = 0.033) or EpCAM expression (P < 0.001) and rarely by epithelial-mesenchymal transition defined as CK8/18(-)vimentin(+) phenotype (P = 0.003). ALDH1-positive tumor and stromal cells were detected in 33% and 41% of hormone naive lymph node metastases (n = 63), 52% and 24% of castration resistant bone metastases, as well as 89% and 28% of castration resistant visceral metastases (n = 21), respectively. We have determined that contrary to tumor cell ALDH1, the presence of stromal ALDH1 is associated with epithelial phenotype of primary PCa, improved clinical outcome, and is less frequent in PCa metastases.
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http://dx.doi.org/10.1016/j.trsl.2018.08.007DOI Listing
January 2019

Somatic aberrations of BRCA1 gene are associated with ALDH1, EGFR, and tumor progression in prostate cancer.

Int J Cancer 2019 02 22;144(3):607-614. Epub 2018 Oct 22.

Institute of Tumour Biology, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.

BRCA1 is a pivotal tumor suppressor. Its dysfunction is known to play a role in different tumors. Among others, BRCA1 germline mutations account for higher risk and more aggressive course of prostate cancer (PCa). In addition, somatic BRCA1 gene loss was demonstrated to be a signature of PCa dissemination to lymph nodes and peripheral blood, and indicate worse clinical outcome. In order to substantiate the data for BRCA1 gene loss in PCa and reveal its phenotypical background, BRCA1 gene status was assessed in a large cohort of PCa patients and compared to different molecular factors. BRCA1 gene dosage was assessed in 2398 tumor samples from 1,199 PCa patients using fluorescent in situ hybridization. It was compared to clinico-pathological parameters, patients' outcome as well as selected proteins (Ki-67, apoptosis marker, cytokeratins, vimentin, E- and N-cadherin, ALDH1 and EGFR) examined immunohistochemically. BRCA1 losses were found in 10%, whereas gains appeared in 7% of 603 informative PCa patients. BRCA1 losses correlated to higher T stage (p = 0.027), Gleason score (p = 0.039), shorter time to biochemical recurrence in patients with Gleason score > 7 independently of other factors (multivariate analysis, p = 0.005) as well as expression of proteins regulating stemness and epithelial-mesenchymal transition, that is, ALDH1 (p = 0.021) and EGFR (p = 0.011), respectively. BRCA1 gains correlated to shorter time to metastasis (p = 0.012) and expression of ALDH1 (p = 0.014). These results support the assumption that BRCA1 gene losses contribute to a progressive and stem cell-like phenotype of PCa. Furthermore, they reveal that also BRCA1 gain conceivably representing loss-of-function might mark more invasive tumors.
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http://dx.doi.org/10.1002/ijc.31905DOI Listing
February 2019

Circulating tumor cells: potential markers of minimal residual disease in ovarian cancer? a study of the OVCAD consortium.

Oncotarget 2017 Dec 16;8(63):106415-106428. Epub 2017 Nov 16.

Institute of Clinical Chemistry, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany.

Purpose: In 75% of ovarian cancer patients the tumor mass is completely eradicated by established surgical and cytotoxic treatment; however, the majority of the tumors recur within 24 months. Here we investigated the role of circulating tumor cells (CTCs) indicating occult tumor load, which remains inaccessible by established diagnostics.

Experimental Design: Blood was taken at diagnosis (baseline samples, = 102) and six months after completion of adjuvant first-line chemotherapy (follow-up samples; = 78). CTCs were enriched by density gradient centrifugation. A multi-marker immunostaining was established and further complemented by FISH on CTCs and tumor/metastasis tissues using probes for stem-cell like fusion genes MECOM and HHLA1.

Results: CTCs were observed in 26.5% baseline and 7.7% follow-up blood samples at a mean number of 12.4 and 2.8 CTCs per ml blood, respectively. Baseline CTCs indicated a higher risk of death in R0 patients with complete gross resection (univariate: HR 2.158, 95% CI 1.111-4.191, = 0.023; multivariate: HR 2.720, 95% CI 1.340-5.522, = 0.006). At follow-up, the presence of CTCs was associated with response to primary treatment as assessed using RECIST criteria. Chromosomal gains at MECOM and HHLA1 loci suggest that the observed cells were cancer cells and reflect pathophysiological decisive chromosomal aberrations of the primary and metastatic tumors.

Conclusions: Our data suggest that CTCs detected by the multi-marker protein panel and/or MECOM/HHLA1 FISH represent minimal residual disease in optimally debulked ovarian cancer patients. The role of CTCs cells especially for clinical therapy stratification of the patients has to be validated in consecutive larger studies applying standardized treatment schemes.
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http://dx.doi.org/10.18632/oncotarget.22468DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5739744PMC
December 2017

Exploring prostate cancer genome reveals simultaneous losses of PTEN, FAS and PAPSS2 in patients with PSA recurrence after radical prostatectomy.

Int J Mol Sci 2015 Feb 11;16(2):3856-69. Epub 2015 Feb 11.

Prostate Center, Department of Urology, University Hospital Muenster, Albert-Schweitzer-Campus 1, Gebaeude 1A, Muenster D-48149, Germany.

The multifocal nature of prostate cancer (PCa) creates a challenge to patients' outcome prediction and their clinical management. An approach that scrutinizes every cancer focus is needed in order to generate a comprehensive evaluation of the disease, and by correlating to patients' clinico-pathological information, specific prognostic biomarker can be identified. Our study utilized the Affymetrix SNP 6.0 Genome-wide assay to investigate forty-three fresh frozen PCa tissue foci from twenty-three patients. With a long clinical follow-up period that ranged from 2.0-9.7 (mean 5.4) years, copy number variation (CNV) data was evaluated for association with patients' PSA status during follow-up. From our results, the loss of unique genes on 10q23.31 and 10q23.2-10q23.31 were identified to be significantly associated to PSA recurrence (p < 0.05). The implication of PTEN and FAS loss (10q23.31) support previous reports due to their critical roles in prostate carcinogenesis. Furthermore, we hypothesize that the PAPSS2 gene (10q23.2-10q23.31) may be functionally relevant in post-operative PSA recurrence because of its reported role in androgen biosynthesis. It is suggestive that the loss of the susceptible region on chromosome 10q, which implicates PTEN, FAS and PAPSS2 may serve as genetic predictors of PSA recurrence after radical prostatectomy.
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http://dx.doi.org/10.3390/ijms16023856DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4346930PMC
February 2015

AKT3 regulates ErbB2, ErbB3 and estrogen receptor α expression and contributes to endocrine therapy resistance of ErbB2(+) breast tumor cells from Balb-neuT mice.

Cell Signal 2014 May 24;26(5):1021-9. Epub 2014 Jan 24.

Institute of Biochemistry and Signal Transduction, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany. Electronic address:

ErbB2(+) breast cancer is an aggressive breast cancer subtype generally associated with lower estrogen receptor alpha (ERα) expression and more aggressive tumor behavior compared to ERα(+)/ErbB2(-) breast cancer. The ErbB2(+) phenotype is associated with resistance to endocrine therapy, e.g. the selective estrogen receptor modulator Tamoxifen. However, the mechanisms underlying endocrine resistance are not fully understood. Here, we investigated the impact of AKT signaling and distinct functional roles of AKT isoforms in ErbB2(+) breast cancer from Balb-neuT mice. AKT isoform specific in vitro kinase assays revealed that AKT3 is activated in Balb-neuT breast tumors in comparison to normal murine breast tissue. Knock-down of AKT3, but not of AKT1 or AKT2, led to reduced expression and tyrosine-phosphorylation of ErbB2 and ErbB3 in Balb-neuT-derived mammary tumor cells. In contrast, expression of ERα was strongly up-regulated and phosphorylation of the AKT substrate Foxo3a which regulates ERα transcription was decreased in AKT3 knockdown cells. These data suggest that ERα expression is down regulated via AKT3/Foxo3a signaling in ErbB2(+) breast cancer cells. Furthermore, up-regulation of ERα after depletion of AKT3 resulted in a significant increase in Tamoxifen responsiveness of Balb-neuT-derived mammary tumor cells. In addition, Tamoxifen resistant human breast cancer cell lines showed increased AKT3 expression and activity in comparison to Tamoxifen responsive MCF-7 cells. Finally, by AKT isoform specific in vitro kinase assays of human breast cancer samples, AKT3 activity was detected in ErbB2(+) and triple negative tumors but not in ERα(+) breast cancer. Our data indicate that AKT3 regulates the expression of ErbB2, ErbB3 and ERα and demonstrate that down-regulation of activated AKT3 can sensitize ErbB2(+) breast cancer cells for treatment with Tamoxifen. Therefore, AKT3 targeting might be a new promising strategy for therapy of ErbB2(+)/ERα(-) breast cancer and might further increase the responsiveness to an endocrine therapy approach.
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http://dx.doi.org/10.1016/j.cellsig.2014.01.018DOI Listing
May 2014

Genome-wide investigation of multifocal and unifocal prostate cancer-are they genetically different?

Int J Mol Sci 2013 Jun 3;14(6):11816-29. Epub 2013 Jun 3.

Prostate Center, Department of Urology, University Hospital Muenster, Albert-Schweitzer-Campus 1, Gebaeude 1A, Muenster D-48149, Germany.

Prostate cancer is widely observed to be biologically heterogeneous. Its heterogeneity is manifested histologically as multifocal prostate cancer, which is observed more frequently than unifocal prostate cancer. The clinical and prognostic significance of either focal cancer type is not fully established. To investigate prostate cancer heterogeneity, the genetic profiles of multifocal and unifocal prostate cancers were compared. Here, we report observations deduced from tumor-tumor comparison of copy number alteration data of both focal categories. Forty-one fresh frozen prostate cancer foci from 14 multifocal prostate cancers and eight unifocal prostate cancers were subjected to copy number variation analysis with the Affymetrix SNP 6.0 microarray tool. With the investigated cases, tumors obtained from a single prostate exhibited different genetic profiles of variable degrees. Further comparison identified no distinct genetic pattern or signatures specific to multifocal or unifocal prostate cancer. Our findings suggest that samples obtained from multiple sites of a single unifocal prostate cancer show as much genetic heterogeneity and variability as separate tumors obtained from a single multifocal prostate cancer.
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http://dx.doi.org/10.3390/ijms140611816DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3709757PMC
June 2013

Frequent genetic alterations in EGFR- and HER2-driven pathways in breast cancer brain metastases.

Am J Pathol 2013 Jul 9;183(1):83-95. Epub 2013 May 9.

Department of Tumor Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

Current standard systemic therapies for treating breast cancer patients with brain metastases are inefficient. Targeted therapies against human epidermal growth factor receptors are of clinical interest because of their alteration in a subset of breast cancers (BCs). We analyzed copy number, mutation status, and protein expression of epidermal growth factor receptor (EGFR), human epidermal growth factor 2 (HER2), phosphatase and tensin homologue (PTEN), and PI3K catalytic subunit (PIK3CA) in 110 ductal carcinoma in situ, primary tumor, and metastatic BC samples. Alterations in EGFR, HER2, and PTEN, alone or in combination, were found in a significantly larger fraction of breast cancer brain metastases tumor tissue compared with samples from primary tumors with good prognosis, bone relapse, or other distant metastases (all P < 0.05). Primary tumor patients with a subsequent brain relapse showed almost equally high frequencies of especially EGFR and PTEN alteration as the breast cancer brain metastases patients. PIK3CA was not associated with an increased risk of brain metastases. Genetic alterations in both EGFR and PTEN were especially common in triple-negative breast cancer patients and rarely were seen among HER2-positive patients. In conclusion, we identified two independent high-risk primary BC subgroups for developing brain metastases, represented by genetic alterations in either HER2 or EGFR/PTEN-driven pathways. In contrast, none of these pathways was associated with an increased risk of bone metastasis. These findings highlight the importance of both pathways as possible targets in the treatment of brain metastases in breast cancer.
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http://dx.doi.org/10.1016/j.ajpath.2013.03.023DOI Listing
July 2013

EGFR intron-1 CA repeat polymorphism is a predictor of relapse and survival in complete resected only surgically treated esophageal cancer.

Target Oncol 2014 Mar 2;9(1):43-52. Epub 2013 Feb 2.

Department of General, Visceral and Thoracic Surgery, University Medical Center Hamburg-Eppendorf, Martini Strasse 52, 20246, Hamburg, Germany,

Basal transcription regulation of the epidermal growth factor receptor is dependent upon a CA simple sequence repeat polymorphism in the intron-1 (CA-SSR-1). Here, we evaluate the role of CA-SSR-1 in complete resected esophageal cancer (EC) patients without neoadjuvant or adjuvant treatment. Genomic DNA was extracted from peripheral blood leukocytes of 241 patients. To determine the number of the CA repeats in the CA-SSR-1, DNA was amplified by polymerase chain reaction and sequenced. The results were correlated with clinicopathological parameters and clinical outcome. Three genotypes were defined based on cut-off points for short allele (S) with ≤18 and long allele (L) >18 CA repeats. A steadily increasing risk was evident between LL, SL, and SS genotype for larger tumor size, presence of lymph node metastases, and disseminated tumor cells in bone marrow as well as tumor recurrence (P < 0.001, chi-square test). A gradual decrease in disease-free and overall survival (OS) was present among LL, SL, and SS patients (P < 0.001, log-rank test). The different outcomes were also evident in nodal status and histological type adjusted subgroup analyses. CA-SSR-1 was identified as the strongest independent prognosticator of tumor recurrence and OS (P < 0.001, Cox regression analysis). CA-SSR-1 is a strong predictive factor for tumor recurrence and overall survival in patients with complete resected esophageal cancer without neoadjuvant or adjuvant therapy.
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http://dx.doi.org/10.1007/s11523-013-0260-2DOI Listing
March 2014

Hybrid cells derived from breast epithelial cell/breast cancer cell fusion events show a differential RAF-AKT crosstalk.

Cell Commun Signal 2012 Apr 9;10(1):10. Epub 2012 Apr 9.

Zentrum für Biomedizinische Ausbildung und Forschung der UWH (ZBAF), Institute of Immunology, Witten/Herdecke University, Stockumer Str, 10, 58448 Witten, Germany.

Background: The biological phenomenon of cell fusion has been linked to several characteristics of tumour progression, including an enhanced metastatogenic capacity and an enhanced drug resistance of hybrid cells. We demonstrated recently that M13SV1-EGFP-Neo breast epithelial cells exhibiting stem cell characteristics spontaneously fused with MDA-MB-435-Hyg breast cancer cells, thereby giving rise to stable M13MDA435 hybrid cells, which are characterised by a unique gene expression profile and migratory behaviour. Here we investigated the involvement of the PLC-β/γ1, PI3K/AKT and RAS-RAF-ERK signal transduction cascades in the EGF and SDF-1α induced migration of two M13MDA435 hybrid cell clones in comparison to their parental cells.

Results: Analysis of the migratory behaviour by using the three-dimensional collagen matrix migration assay showed that M13SV1-EGFP-Neo cells as well as M13MDA435 hybrid cells, but not the breast cancer cell line, responded to EGF stimulation with an increased locomotory activity. By contrast, SDF-1α solely stimulated the migration of M13SV1-EGFP-Neo cells, whereas the migratory activity of the other cell lines was blocked. Analysis of signal transduction cascades revealed a putative differential RAF-AKT crosstalk in M13MDA435-1 and -3 hybrid cell clones. The PI3K inhibitor Ly294002 effectively blocked the EGF induced migration of M13MDA435-3 hybrid cells, whereas the EGF induced locomotion of M13MDA435-1 hybrid cells was markedly increased. Analysis of RAF-1 S259 phosphorylation, being a major mediator of the negative regulation of RAF-1 by AKT, showed decreased pRAF-1 S259 levels in LY294002 treated M13MDA435-1 hybrid cells. By contrast, pRAF-1 S259 levels remained unaltered in the other cell lines. Inhibition of PI3K/AKT signalling by Ly294002 relieves the AKT mediated phosphorylation of RAF-1, thereby restoring MAPK signalling.

Conclusions: Here we show that hybrid cells could evolve exhibiting a differential active RAF-AKT crosstalk. Because PI3K/AKT signalling has been chosen as a target for anti-cancer therapies our data might point to a possible severe side effect of AKT targeted cancer therapies. Inhibition of PI3K/AKT signalling in RAF-AKT crosstalk positive cancer (hybrid) cells could result in a progression of these cells. Thus, not only the receptor (activation) status, but also the activation of signal transduction molecules should be analysed thoroughly prior to therapy.
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http://dx.doi.org/10.1186/1478-811X-10-10DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3349602PMC
April 2012

Pro-inflammatory wnt5a and anti-inflammatory sFRP5 are differentially regulated by nutritional factors in obese human subjects.

PLoS One 2012 23;7(2):e32437. Epub 2012 Feb 23.

Department I of Internal Medicine, University of Kiel, Kiel, Germany.

Background: Obesity is associated with macrophage infiltration of adipose tissue. These inflammatory cells affect adipocytes not only by classical cytokines but also by the secreted glycopeptide wnt5a. Healthy adipocytes are able to release the wnt5a inhibitor sFRP5. This protective effect, however, was found to be diminished in obesity. The aim of the present study was to examine (1) whether obese human subjects exhibit increased serum concentrations of wnt5a and (2) whether wnt5a and/or sFRP5 serum concentrations in obese subjects can be influenced by caloric restriction.

Methodology: 23 obese human subjects (BMI 44.1 ± 1.1 kg/m(2)) and 12 age- and sex-matched lean controls (BMI 22.3 ± 0.4 kg/m(2)) were included in the study. Obese subjects were treated with a very low-calorie diet (approximately 800 kcal/d) for 12 weeks. Body composition was assessed by impedance analysis, insulin sensitivity was estimated by HOMA-IR and the leptin-to-adiponectin ratio and wnt5a and sFRP5 serum concentrations were measured by ELISA. sFRP5 expression in human adipose tissue biopsies was further determined on protein level by immunohistology.

Principal Findings: Pro-inflammatory wnt5a was not measurable in any serum sample of lean control subjects. In patients with obesity, however, wnt5a became significantly detectable consistent with low grade inflammation in such subjects. Caloric restriction resulted in a weight loss from 131.9 ± 4.0 to 112.3 ± 3.2 kg in the obese patients group. This was accompanied by a significant decrease of HOMA-IR and leptin-to-adiponectin ratio, indicating improved insulin sensitivity. Interestingly, these metabolic improvements were associated with a significant increase in serum concentrations of the anti-inflammatory factor and wnt5a-inhibitor sFRP5.

Conclusions/significance: Obesity is associated with elevated serum levels of pro-inflammatory wnt5a in humans. Furthermore, caloric restriction beneficially affects serum concentrations of anti-inflammatory sFRP5 in such subjects. These findings suggest a novel regulatory system in low grade inflammation in obesity, which can be influenced by nutritional therapy.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0032437PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3285685PMC
August 2012

Site-specific chromatin immunoprecipitation: a selective method to individually analyze neighboring transcription factor binding sites in vivo.

BMC Res Notes 2012 Feb 20;5:109. Epub 2012 Feb 20.

Institute of Bioinformatics, University Hospital of Muenster, Muenster, Germany.

Background: Transcription factors (TFs) and their binding sites (TFBSs) play a central role in the regulation of gene expression. It is therefore vital to know how the allocation pattern of TFBSs affects the functioning of any particular gene in vivo. A widely used method to analyze TFBSs in vivo is the chromatin immunoprecipitation (ChIP). However, this method in its present state does not enable the individual investigation of densely arranged TFBSs due to the underlying unspecific DNA fragmentation technique. This study describes a site-specific ChIP which aggregates the benefits of both EMSA and in vivo footprinting in only one assay, thereby allowing the individual detection and analysis of single binding motifs.

Findings: The standard ChIP protocol was modified by replacing the conventional DNA fragmentation, i. e. via sonication or undirected enzymatic digestion (by MNase), through a sequence specific enzymatic digestion step. This alteration enables the specific immunoprecipitation and individual examination of occupied sites, even in a complex system of adjacent binding motifs in vivo. Immunoprecipitated chromatin was analyzed by PCR using two primer sets - one for the specific detection of precipitated TFBSs and one for the validation of completeness of the enzyme digestion step. The method was established exemplary for Sp1 TFBSs within the egfr promoter region. Using this site-specific ChIP, we were able to confirm four previously described Sp1 binding sites within egfr promoter region to be occupied by Sp1 in vivo. Despite the dense arrangement of the Sp1 TFBSs the improved ChIP method was able to individually examine the allocation of all adjacent Sp1 TFBS at once. The broad applicability of this site-specific ChIP could be demonstrated by analyzing these SP1 motifs in both osteosarcoma cells and kidney carcinoma tissue.

Conclusions: The ChIP technology is a powerful tool for investigating transcription factors in vivo, especially in cancer biology. The established site-specific enzyme digestion enables a reliable and individual detection option for densely arranged binding motifs in vivo not provided by e.g. EMSA or in vivo footprinting. Given the important function of transcription factors in neoplastic mechanism, our method enables a broad diversity of application options for clinical studies.
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http://dx.doi.org/10.1186/1756-0500-5-109DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3312844PMC
February 2012

The interplay of HER2/HER3/PI3K and EGFR/HER2/PLC-γ1 signalling in breast cancer cell migration and dissemination.

J Pathol 2012 Jun 21;227(2):234-44. Epub 2012 Mar 21.

Institute of Immunology, Witten/Herdecke University, Germany.

HER2 signalling by heterodimerisation with EGFR and HER3 in breast cancer is associated with worst outcome of the afflicted patients, which is attributed not only to the aggressiveness of such tumours but also to therapy resistance. Thus, in the present study we investigated the role of EGFR, HER2 and HER3 lateral signalling in cell migration by applying the MDA-MB-468-HER2 (MDA-HER2) breast cancer cell line, representing a valid model system. Knockdown of HER3 expression by siRNA resulted in decreased phosphorylated AKT (pAKT) levels, abrogated epidermal growth factor (EGF)-mediated PLC-γ1 activation and a diminished EGF-induced migratory activity, depicting the interplay of EGF receptor (EGFR)/HER2/PLC-γ1 and HER2/HER3/PI3K signalling in mediating the migration of EGFR/HER2/HER3-expressing breast cancer cells. Since therapy failure usually arises from metastatic cells, we further investigated whether HER3 signalling was active in established breast cancer disseminated tumour cell (DTC) lines as well as in primary DTCs derived from breast cancer patients. EGF treatment of DTC lines resulted solely in increased pAKT S473 levels, whereas in MDA-HER2 cells both pAKT S473 and pAKT T308 levels were increased upon EGF stimulation. Moreover, despite active HER3 molecules, as indicated by pTyr1222 staining, about 90% of analysed breast cancer patient DTCs exhibited very low or even no detectable pAKT S473 levels, suggesting that these cells might have fallen into dormancy. In summary, our data indicate the important role in EGFR, HER2 and HER3 lateral signalling in breast cancer cell migration. Moreover, our data further show that primary tumour cells and DTCs can vary in their HER activation status, which is important to know in the context of cancer therapy.
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http://dx.doi.org/10.1002/path.3991DOI Listing
June 2012

Quantitative high-resolution genomic analysis of single cancer cells.

PLoS One 2011 30;6(11):e26362. Epub 2011 Nov 30.

Department of Tumor Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

During cancer progression, specific genomic aberrations arise that can determine the scope of the disease and can be used as predictive or prognostic markers. The detection of specific gene amplifications or deletions in single blood-borne or disseminated tumour cells that may give rise to the development of metastases is of great clinical interest but technically challenging. In this study, we present a method for quantitative high-resolution genomic analysis of single cells. Cells were isolated under permanent microscopic control followed by high-fidelity whole genome amplification and subsequent analyses by fine tiling array-CGH and qPCR. The assay was applied to single breast cancer cells to analyze the chromosomal region centred by the therapeutical relevant EGFR gene. This method allows precise quantitative analysis of copy number variations in single cell diagnostics.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0026362PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3227572PMC
April 2012

15-Hydroxyprostaglandin dehydrogenase associates with poor prognosis in breast cancer, induces epithelial-mesenchymal transition, and promotes cell migration in cultured breast cancer cells.

J Pathol 2012 Mar 17;226(4):674-86. Epub 2012 Jan 17.

Medical Biotechnology, VTT Technical Research Centre of Finland and Turku Centre for Biotechnology, University of Turku, Finland.

Breast cancer is the most frequent cancer and the leading cause of cancer-related deaths in women worldwide. The prognosis of breast cancer is tightly correlated with the degree of spread beyond the primary tumour. Arachidonic acid (AA) and prostaglandin E(2) (PGE(2)) are known to regulate tumour metastasis enabling epithelial-mesenchymal transition (EMT). However, the detailed role of 15-hydroxyprostaglandin dehydrogenase (HPGD), the key enzyme degrading prostaglandin E(2) , remains unclear in breast cancer. Here, we show that HPGD mRNA is overexpressed in a subset of clinical breast cancers compared to normal breast tissue samples and that high HPGD mRNA expression associates with poor prognosis. Immunohistochemical staining of primary breast cancer and lymph node metastasis tissue samples confirmed high HPGD protein expression in 20% of the samples, as well as associated HPGD expression with aggressive characteristics, such as increased risk of disease relapse and shorter disease-free survival. Results from cultured cells indicated abundant HPGD expression in highly metastatic breast cancer cells, and impairment of HPGD expression using RNA interference led to a significant decrease in transforming growth factor-β signalling, in cellular arachidonic acid levels as well as in cell migration. Furthermore, gene expression microarray analysis followed by quantitative RT-PCR validation showed that HPGD silencing decreased aryl hydrocarbon receptor signalling and induced mesenchymal-epithelial transition. In conclusion, our results indicate that HPGD is highly expressed in metastatic and aggressive breast cancer and promotes EMT and migration in breast cancer cells.
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http://dx.doi.org/10.1002/path.3956DOI Listing
March 2012

Systematic analysis of in vitro chemosensitivity and mib-1 expression in molecular breast cancer subtypes.

Eur J Cancer 2012 Sep 13;48(13):2066-74. Epub 2011 Sep 13.

Department of Gynecology and Obstetrics, University Hospital Muenster, Muenster, Germany.

Background: Molecular breast cancer subgroups show differences with regard to prognosis and response to chemotherapy. In vitro chemotherapy sensitivity and resistance assays (CSRAs) are a means to directly evaluate tumour cell response to a given drug.

Methods: Using tissue microarray (TMA) analysis, 550 invasive breast cancers were investigated for the expression of oestrogen receptor (ER), progesterone receptor (PR), vimentin, Ck5, Ck14, Ck19, HER2 and Mib-1/Ki-67. All carcinomas were subjected to in vitro CSRA analysis using three separate chemotherapy combinations. In vitro chemotherapy sensitivity was established using an adenosine triphosphate (ATP) bioluminescence assay. Results of immunohistochemical staining and in vitro response were correlated.

Results: Mib-1 expression was associated with sensitivity against Paclitaxel/Epirubicin (p = 0.014) and Docetaxel/Epirubicin (p = 0.014). Mib-1 expression was positively/negatively correlated with expression of basal/luminal markers, respectively. Hierarchical clustering revealed three subtypes, resembling luminal, basal-like and HER2-like breast cancer subtypes. In vitro response for Paclitaxel/Epirubicin was most frequently observed for cases in the basal category (40.3%) compared to HER2-like (25.8%) and luminal cases (28.6%). In multivariate analysis expression of Mib-1 was not a significant independent predictor of in vitro response to chemotherapy.

Conclusion: Breast cancer molecular subclasses show differences regarding in vitro chemotherapy sensitivity. These may in part explain differences observed between breast cancer molecular subtypes in vivo.
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http://dx.doi.org/10.1016/j.ejca.2011.08.006DOI Listing
September 2012

Distinct functional roles of Akt isoforms for proliferation, survival, migration and EGF-mediated signalling in lung cancer derived disseminated tumor cells.

Cell Signal 2011 Dec 12;23(12):1952-60. Epub 2011 Jul 12.

Institute of Biochemistry and Signal Transduction, Center of Experimental Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany.

Single disseminated tumor cells (DTC) can be detected in the bone marrow (BM) from 20% to 60% of patients with various tumors including non-small cell lung cancer (NSCLC). Detection of DTC in the BM of NSCLC patients is associated with poor prognosis and may be responsible for metastatic relapse. However, the functional properties of DTC are widely unknown. Here, we performed the first functional analysis of DTC focusing on the activation of the PI3K/Akt signalling pathway and the functional roles of Akt isoforms. In vitro kinase assays revealed a high activity of Akt3 in NSCLC-derived DTC. Proliferation and survival of DTC was reduced by depletion of Akt3 and to a lesser extend by Akt1, but not after depletion of Akt2. The major effect of Akt3 on the proliferation of DTC was associated with an Akt3-mediated regulation of both, cyclin D1 and cyclin D3, whereas Akt1 regulated the expression of cyclin D1 only. In contrast all three Akt isoforms, especially Akt2, were involved in the regulation of migration. Analysis of signalling events downstream of distinct Akt isoforms revealed that expression levels of urokinase-type plasminogen activator and its receptor were decreased after knockdown of Akt1 and Akt3. In addition, EGF-stimulated proliferative and anti-apoptotic signals are mediated by Akt1 and Akt3 in DTC. Finally, by immunofluorescence staining of primary DTC from BM samples of lung cancer patients, pAkt(S473) and Akt3 positive DTC were detected in vivo. Our data demonstrate that Akt1 and notably Akt3 regulate proliferation, survival, migration and EGF-mediated signal transduction in NSCLC-derived DTC.
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http://dx.doi.org/10.1016/j.cellsig.2011.07.003DOI Listing
December 2011

Influence of whole arm loss of chromosome 16q on gene expression patterns in oestrogen receptor-positive, invasive breast cancer.

J Pathol 2011 Aug 27;224(4):517-28. Epub 2011 Jun 27.

Institute of Pathology, University of Münster, Germany.

A whole chromosome arm loss of 16q belongs to the most frequent and earliest chromosomal alterations in invasive and in situ breast cancers of all common subtypes. Besides E-cadherin, several putative tumour suppressor genes residing on 16q in breast cancer have been investigated. However, the significance of these findings has remained unclear. Thus, other mechanisms leading to gene loss of function (eg haploinsufficiency, or distortion of multiple regulative subnetworks) remain to be tested as a hypothesis. To define the effect on gene expression of whole-arm loss of chromosome 16q in invasive breast cancer, we performed global gene expression analysis on a series of 18 genetically extensively characterized invasive ductal breast carcinomas and verified the results by quantitative real-time PCR (qRT-PCR). The distribution of the differential genes across the genome and their expression status was studied. A second approach by qRT-PCR in an independent series of 30 breast carcinomas helped to narrow down the observed effect. Whole-arm chromosome 16q losses, irrespective of other chromosomal changes, are associated with decreased expression of a number of candidate genes located on 16q (eg CDA08, CGI-128, SNTB2, NQO1, SF3B3, KIAA0174, ATBF1, GABARAPL2, KARS, GCSH, MBTPS1 and ZDHHC7) in breast carcinomas with a low degree of genetic instability. qRT-PCR provided evidence to suggest that the expression of these genes was reduced in a gene dosage-dependent manner. The differential expression of the candidate genes according to the chromosomal 16q-status vanished in genetically advanced breast cancer cases and changed ER status. These results corroborate previous reports about the importance of whole-arm loss of chromosome 16q in breast carcinogenesis and give evidence for the first time that haploinsufficiency, in the sense of a gene dosage effect, might be an important contributing factor in the early steps of breast carcinogenesis.
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http://dx.doi.org/10.1002/path.2938DOI Listing
August 2011

Cellular and tumor radiosensitivity is correlated to epidermal growth factor receptor protein expression level in tumors without EGFR amplification.

Int J Radiat Oncol Biol Phys 2011 Jul 20;80(4):1181-8. Epub 2011 Apr 20.

Laboratory of Radiobiology & Experimental Radiooncology, University Medical Center Hamburg-Eppendorf, Hubertus Wald Tumor Center, Hamburg, Germany.

Purpose: There is conflicting evidence for whether the expression of epidermal growth factor receptor in human tumors can be used as a marker of radioresponse. Therefore, this association was studied in a systematic manner using squamous cell carcinoma (SCC) cell lines grown as cell cultures and xenografts.

Methods And Materials: The study was performed with 24 tumor cell lines of different tumor types, including 10 SCC lines, which were also investigated as xenografts on nude mice. Egfr gene dose and the length of CA-repeats in intron 1 were determined by polymerase chain reaction, protein expression in vitro by Western blot and in vivo by enzyme-linked immunosorbent assay, and radiosensitivity in vitro by colony formation. Data were correlated with previously published tumor control dose 50% data after fractionated irradiation of xenografts of the 10 SCC.

Results: EGFR protein expression varies considerably, with most tumor cell lines showing moderate and only few showing pronounced upregulation. EGFR upregulation could only be attributed to massive gene amplification in the latter. In the case of little or no amplification, in vitro EGFR expression correlated with both cellular and tumor radioresponse. In vivo EGFR expression did not show this correlation.

Conclusions: Local tumor control after the fractionated irradiation of tumors with little or no gene amplification seems to be dependent on in vitro EGFR via its effect on cellular radiosensitivity.
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http://dx.doi.org/10.1016/j.ijrobp.2011.02.043DOI Listing
July 2011

Characterization of hybrid cells derived from spontaneous fusion events between breast epithelial cells exhibiting stem-like characteristics and breast cancer cells.

Clin Exp Metastasis 2011 Jan 28;28(1):75-90. Epub 2010 Oct 28.

Institute of Immunology, Zentrum für Biomedizinische Ausbildung und Forschung an der UWH (ZBAF), Witten/Herdecke University, Stockumer Str. 10, 58448 Witten, Germany.

Several data of the past years clearly indicated that the fusion of tumor cells and tumor cells or tumor cells and normal cells can give rise to hybrids cells exhibited novel properties such as an increased malignancy, drug resistance, or resistance to apoptosis. In the present study we characterized hybrid cells derived from spontaneous fusion events between the breast epithelial cell line M13SV1-EGFP-Neo and two breast cancer cell lines: HS578T-Hyg and MDA-MB-435-Hyg. Short-tandem-repeat analysis revealed an overlap of parental alleles in all hybrid cells indicating that hybrid cells originated from real cell fusion events. RealTime-PCR-array gene expression data provided evidence that each hybrid cell clone exhibited a unique gene expression pattern, resulting in a specific resistance of hybrid clones towards chemotherapeutic drugs, such as doxorubicin and paclitaxel, as well as a specific migratory behavior of hybrid clones towards EGF. For instance, M13MDA435-4 hybrids showed a marked resistance towards etoposide, doxorubicin and paclitaxel, whereas hybrid clones M13MDA-435-1 and -2 were only resistant towards etoposide. Likewise, all investigated M13MDA435 hybrids responded to EGF with an increased migratory activity, whereas the migration of parental MDA-MB-435-Hyg cells was blocked by EGF, suggesting that M13MDA435 hybrids may have acquired a new motility pathway. Similar findings have been obtained for M13HS hybrids. We conclude from our data that they further support the hypothesis that cell fusion could give rise to drug resistant and migratory active tumor (hybrid) cells in cancer.
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http://dx.doi.org/10.1007/s10585-010-9359-3DOI Listing
January 2011

BRCA1 loss preexisting in small subpopulations of prostate cancer is associated with advanced disease and metastatic spread to lymph nodes and peripheral blood.

Clin Cancer Res 2010 Jul 30;16(13):3340-8. Epub 2010 Jun 30.

Institute of Tumor Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

Purpose: A preliminary study performed on a small cohort of multifocal prostate cancer (PCa) detected BRCA1 allelic imbalances among circulating tumor cells (CTC). The present analysis was aimed to elucidate the biological and clinical roles of BRCA1 losses in metastatic spread and tumor progression in PCa patients.

Experimental Design: To map molecular progression in PCa outgrowth, we used fluorescence in situ hybridization analysis of primary tumors and lymph node sections, and CTCs from peripheral blood.

Results: We found that 14% of 133 tested patients carried monoallelic BRCA1 loss in at least one tumor focus. Extended molecular analysis of chr17q revealed that this aberration was often a part of larger cytogenetic rearrangement involving chr17q21 accompanied by allelic imbalance of the tumor suppressor gene PTEN and lack of BRCA1 promoter methylation. The BRCA1 losses correlated with advanced T stage (P < 0.05), invasion to pelvic lymph nodes (P < 0.05), as well as biochemical recurrence (P < 0.01). Their prevalence was twice as high within 62 lymph node metastases (LNM) as in primary tumors (27%, P < 0.01). The analysis of 11 matched primary PCa-LNM pairs confirmed the suspected transmission of genetic abnormalities between these two sites. In four of seven patients with metastatic disease, BRCA1 losses appeared in a minute fraction of cytokeratin- and vimentin-positive CTCs.

Conclusions: Small subpopulations of PCa cells bearing BRCA1 losses might be one confounding factor initiating tumor dissemination and might provide an early indicator of shortened disease-free survival.
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http://dx.doi.org/10.1158/1078-0432.CCR-10-0150DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3042432PMC
July 2010

Detection and clinical relevance of early disseminated breast cancer cells depend on their cytokeratin expression pattern.

Breast Cancer Res Treat 2011 Feb 7;125(3):729-38. Epub 2010 May 7.

Institute of Tumor Biology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany.

The factors determining the clinical relevance of disseminated tumor cells (DTC) in breast cancer patients are largely unknown. Here we compared the specificity and clinical performance of two antibodies frequently used for DTC detection. Reactivities of antibodies A45-B/B3 (A45) and AE1/AE3 (AE) for selected cytokeratins (CK) were assessed by 2-DE Western Blot analysis. Using these antibodies bone marrow aspirates from 391 breast cancer patients (M(0), pT1-3, pN0-3) were screened for the presence of DTC. To obtain prognostic information, patients were followed up over a median of 83 months for time to relapse and 99 months for time to death. Among the analyzed CK, AE detected CK5, CK7, CK8, and CK19, whereas A45 recognized CK7 and CK18. In total, 24 of 391 patients (6.1%) were DTC-positive for A45, and 41 (10.5%) for AE. Although concordance between the two antibodies was 84.4%, overlap among positive cases was only 3.2%. DTC-positivity with AE and A45 was more frequent in patients of higher nodal status (P=0.019 and P=0.036, respectively). Nearly all patients with A45-positive DTC had hormone receptor-positive tumors (23/24), while detection of AE-positive DTC was more frequent among hormone receptor negative patients (P=0.006). Survival analyses of all patients revealed shorter distant disease-free survival (P=0.039) for patients with A45-positive DTC, whereas the prognostic relevance of AE-positive DTC was restricted to node-positive patients. The clinical utility of immunocytochemical (ICC) DTC detection depends on the anti-CK antibody used, which may reflect the complex CK composition of DTC.
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http://dx.doi.org/10.1007/s10549-010-0911-2DOI Listing
February 2011

Discovery of a novel unfolded protein response phenotype of cancer stem/progenitor cells from the bone marrow of breast cancer patients.

J Proteome Res 2010 Jun;9(6):3158-68

Institute for Tumor Biology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, Hamburg, Germany.

Metastases arise from disseminated tumor cells (DTC) that colonize secondary organs. However, DTC survival strategies to start metastatic outgrowth are unclear. The hostile (hypoxic, hypoglycemic) microenvironmental conditions of the bone marrow serve as an ideal model environment for investigation of DTC survival strategies under environmental stress. We investigated the breast cancer DTC cell line BC-M1 established from the bone marrow of a cancer patient by 2-D DIGE and MS analysis. We observed specific overexpression of the unfolded protein response (UPR) proteins Grp78, Grp94, and protein disulfide-isomerase in breast, lung, and prostate cancer DTC cell lines from the bone marrow. The UPR contributes to survival under adverse environmental conditions including chemotherapy. We show in cellular models that Grp78 expression of the UPR is regulated by tyrosine 1248 of ErbB-2. The breast cancer DTC cell lines shared stem/progenitor cell cancer phenotypes (CD44(high)/CD24(low)). Immunocytochemical staining of bone marrow samples from breast cancer patients confirmed in situ high expression of Grp78 and Grp94 in DTC of breast cancer patients, indicating the potential of both proteins as novel markers for DTC detection. Our results suggest the presence of a previously not recognized stress resistant DTC population that combines stem/progenitor attributes with an UPR phenotype.
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http://dx.doi.org/10.1021/pr100039dDOI Listing
June 2010

Selective regain of egfr gene copies in CD44+/CD24-/low breast cancer cellular model MDA-MB-468.

BMC Cancer 2010 Mar 3;10:78. Epub 2010 Mar 3.

Department of Medicine, Hematology and Oncology, University of Muenster, Muenster, Germany.

Background: Increased transcription of oncogenes like the epidermal growth factor receptor (EGFR) is frequently caused by amplification of the whole gene or at least of regulatory sequences. Aim of this study was to pinpoint mechanistic parameters occurring during egfr copy number gains leading to a stable EGFR overexpression and high sensitivity to extracellular signalling. A deeper understanding of those marker events might improve early diagnosis of cancer in suspect lesions, early detection of cancer progression and the prediction of egfr targeted therapies.

Methods: The basal-like/stemness type breast cancer cell line subpopulation MDA-MB-468 CD44high/CD24-/low, carrying high egfr amplifications, was chosen as a model system in this study. Subclones of the heterogeneous cell line expressing low and high EGF receptor densities were isolated by cell sorting. Genomic profiling was carried out for these by means of SNP array profiling, qPCR and FISH. Cell cycle analysis was performed using the BrdU quenching technique.

Results: Low and high EGFR expressing MDA-MB-468 CD44+/CD24-/low subpopulations separated by cell sorting showed intermediate and high copy numbers of egfr, respectively. However, during cell culture an increase solely for egfr gene copy numbers in the intermediate subpopulation occurred. This shift was based on the formation of new cells which regained egfr gene copies. By two parametric cell cycle analysis clonal effects mediated through growth advantage of cells bearing higher egfr gene copy numbers could most likely be excluded for being the driving force. Subsequently, the detection of a fragile site distal to the egfr gene, sustaining uncapped telomere-less chromosomal ends, the ladder-like structure of the intrachromosomal egfr amplification and a broader range of egfr copy numbers support the assumption that dynamic chromosomal rearrangements, like breakage-fusion-bridge-cycles other than proliferation drive the gain of egfr copies.

Conclusion: Progressive genome modulation in the CD44+/CD24-/low subpopulation of the breast cancer cell line MDA-MB-468 leads to different coexisting subclones. In isolated low-copy cells asymmetric chromosomal segregation leads to new cells with regained solely egfr gene copies. Furthermore, egfr regain resulted in enhanced signal transduction of the MAP-kinase and PI3-kinase pathway. We show here for the first time a dynamic copy number regain in basal-like/stemness cell type breast cancer subpopulations which might explain genetic heterogeneity. Moreover, this process might also be involved in adaptive growth factor receptor intracellular signaling which support survival and migration during cancer development and progression.
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http://dx.doi.org/10.1186/1471-2407-10-78DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2841141PMC
March 2010

Inositol 1,4,5-trisphosphate 3-kinase-A is a new cell motility-promoting protein that increases the metastatic potential of tumor cells by two functional activities.

J Biol Chem 2010 Feb 17;285(8):5541-54. Epub 2009 Dec 17.

Institut für Biochemie und Molekularbiologie I, Zelluläre Signaltransduktion, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, D-20246 Hamburg, Germany.

Cellular migration is an essential prerequisite for metastatic dissemination of cancer cells. This study demonstrates that the neuron/testis-specific F-actin-targeted inositol 1,4,5-trisphosphate 3-kinase-A (ITPKA) is ectopically expressed in different human tumor cell lines and during tumor progression in the metastatic tumor model Balb-neuT. High expression of ITPKA increases invasive migration in vitro and metastasis in a xenograft SCID mouse model. Mechanistic studies show that ITPKA promotes migration of tumor cells by two different mechanisms as follows: growth factor independently high levels of ITPKA induce the formation of large cellular protrusions by directly modulating the actin cytoskeleton. The F-actin binding activity of ITPKA stabilizes and bundles actin filaments and thus increases the levels of cellular F-actin. In growth factor-stimulated cells, the catalytically active domain enhances basal ITPKA-induced migration by activating store-operated calcium entry through production of inositol 1,3,4,5-tetrakisphosphate and subsequent inhibition of inositol phosphate 5-phosphatase. These two functional activities of ITPKA stimulating tumor cell migration place the enzyme among the potential targets of anti-metastatic therapy.
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http://dx.doi.org/10.1074/jbc.M109.047050DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2820782PMC
February 2010