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author:("zucker, Jan")
1.  Mesenchymal stem cells and their chondrogenic differentiated and dedifferentiated progeny express chemokine receptor CCR9 and chemotactically migrate toward CCL25 or serum 
Guided migration of chondrogenically differentiated cells has not been well studied, even though it may be critical for growth, repair, and regenerative processes. The chemokine CCL25 is believed to play a critical role in the directional migration of leukocytes and stem cells. To investigate the motility effect of serum- or CCL25-mediated chemotaxis on chondrogenically differentiated cells, mesenchymal stem cells (MSCs) were induced to chondrogenic lineage cells.
MSC-derived chondrogenically differentiated cells were characterized for morphology, histology, immunohistochemistry, quantitative polymerase chain reaction (qPCR), surface profile, and serum- or CCL25-mediated cell migration. Additionally, the chemokine receptor, CCR9, was examined in different states of MSCs.
The chondrogenic differentiated state of MSCs was positive for collagen type II and Alcian blue staining, and showed significantly upregulated expression of COL2A1and SOX9, and downregulated expression of CD44, CD73, CD90, CD105 and CD166, in contrast to the undifferentiated and dedifferentiated states of MSCs. For the chondrogenic differentiated, undifferentiated, and dedifferentiated states of MSCs, the serum-mediated chemotaxis was in a percentage ratio of 33%:84%:85%, and CCL25-mediated chemotaxis was in percentage ratio of 12%:14%:13%, respectively. On the protein level, CCR9, receptor of CCL25, was expressed in the form of extracellular and intracellular domains. On the gene level, qPCR confirmed the expression of CCR9 in different states of MSCs.
CCL25 is an effective cue to guide migration in a directional way. In CCL25-mediated chemotaxis, the cell-migration rate was almost the same for different states of MSCs. In serum-mediated chemotaxis, the cell-migration rate of chondrogenically differentiated cells was significantly lower than that in undifferentiated or dedifferentiated cells. Current knowledge of the surface CD profile and cell migration could be beneficial for regenerative cellular therapies.
PMCID: PMC3854782  PMID: 23958031
Chondrogenically differentiated cells; Stem cells; Cell migration; Chemotaxis; CCL25; CCR9
2.  Reverse Differentiation as a Gene Filtering Tool in Genome Expression Profiling of Adipogenesis for Fat Marker Gene Selection and Their Analysis 
PLoS ONE  2013;8(7):e69754.
During mesenchymal stem cell (MSC) conversion into adipocytes, the adipogenic cocktail consisting of insulin, dexamethasone, indomethacin and 3-isobutyl-1-methylxanthine not only induces adipogenic-specific but also genes for non-adipogenic processes. Therefore, not all significantly expressed genes represent adipogenic-specific marker genes. So, our aim was to filter only adipogenic-specific out of all expressed genes. We hypothesize that exclusively adipogenic-specific genes change their expression during adipogenesis, and reverse during dedifferentiation. Thus, MSC were adipogenic differentiated and dedifferentiated.
Adipogenesis and reverse adipogenesis was verified by Oil Red O staining and expression of PPARG and FABP4. Based on GeneChips, 991 genes were differentially expressed during adipogenesis and grouped in 4 clusters. According to bioinformatic analysis the relevance of genes with adipogenic-linked biological annotations, expression sites, molecular functions, signaling pathways and transcription factor binding sites was high in cluster 1, including all prominent adipogenic genes like ADIPOQ, C/EBPA, LPL, PPARG and FABP4, moderate in clusters 2–3, and negligible in cluster 4. During reversed adipogenesis, only 782 expressed genes (clusters 1–3) were reverted, including 597 genes not reported for adipogenesis before. We identified APCDD1, CHI3L1, RARRES1 and SEMA3G as potential adipogenic-specific genes.
The model system of adipogenesis linked to reverse adipogenesis allowed the filtration of 782 adipogenic-specific genes out of total 991 significantly expressed genes. Database analysis of adipogenic-specific biological annotations, transcription factors and signaling pathways further validated and valued our concept, because most of the filtered 782 genes showed affiliation to adipogenesis. Based on this approach, the selected and filtered genes would be potentially important for characterization of adipogenesis and monitoring of clinical translation for soft-tissue regeneration. Moreover, we report 4 new marker genes.
PMCID: PMC3724870  PMID: 23922792
3.  The EndoPredict Gene-Expression Assay in Clinical Practice - Performance and Impact on Clinical Decisions 
PLoS ONE  2013;8(6):e68252.
The validated EndoPredict assay is a novel tool to predict the risk of metastases of patients with estrogen receptor positive, HER2 negative breast cancer treated with endocrine therapy alone. It has been designed to integrate genomic and clinical information and includes clinico-pathological factors such as tumor size and nodal status. The test is feasible in a decentral setting in molecular pathology laboratories. In this project, we investigated the performance of this test in clinical practice, and performed a retrospective evaluation of its impact on treatment decisions in breast cancer. During one year, EndoPredict assays from 167 patients could be successfully performed. For retrospective evaluation of treatment decisions, a questionnaire was sent to the clinical partner. Regarding the molecular EP class, samples from 56 patients (33.5%) had a low-risk, whereas 111 patients (66.5%) showed a high-risk gene profile. After integration of the clinicopathological factors the combined clinical and molecular score (EPclin) resulted in a low-risk group of 77 patients (46.4%), while 89 (53.6%) had a high risk EPclin score. The EPclin-based estimated median 10-year-risk for metastases with endocrine therapy alone was 11% for the whole cohort. The median handling time averaged three days (range: 0 to 11 days), 59.3% of the tests could be performed in three or less than three days. Comparison of pre- and post-test therapy decisions showed a change of therapy in 37.7% of patients. 16 patients (12.3%) had a change to an additional chemotherapy while 25.4% of patients (n = 33) changed to an endocrine therapy alone. In 73 patients (56.2%) no change of therapy resulted. In 6.1% of patients (n = 8), the patients did not agree to the recommendation of the tumor board. Our results show that the EndoPredict assay could be routinely performed in decentral molecular pathology laboratories and the results markedly change treatment decisions.
PMCID: PMC3694878  PMID: 23826382
4.  Breast Cancer-Associated Thrombotic Microangiopathy 
Breast Care  2011;6(6):441-445.
Thrombotic microangiopathy (TMA) is defined as thrombocytopenia and microangiopathic hemolytic anemia. Cancer-associated TMA, a rare but fatal condition, seems an entity distinct from classical thrombotic thrombocytopenic purpura (TTP)/hemolytic uremic syndrome (HUS).
Patients and Methods
All patients with breast cancer-associated TMA treated at our institution between 2003 and 2008 were analyzed retrospectively. To elucidate pathophysiological mechanisms, we measured the serum activity of the metalloprotease ADAMTS13.
8 patients were identified. All showed bone marrow infiltration of breast cancer as well as thrombocytopenia, schistocytes, and hemolytic anemia. ADAMTS13 activity was mildly decreased in 4/6 patients (20–108%, normal range 30–120%), but none showed severely low levels as is characteristic of classical TTP. 6 patients were treated with anthracycline-containing fractionated chemotherapy, 5/6 patients experienced partial response. Overall survival was 13 months. Fractionated chemotherapy was well tolerated.
Cancer-associated TMA has an underlying mechanism different from classical TTP. While bone marrow infiltration might be of major relevance, ADAMTS13 deficiency seems to be an epiphenomenon. Fractionated chemotherapy resulted in higher remission rates and comparatively long survival.
PMCID: PMC3290020  PMID: 22419897
ADAMTS13; Bone marrow infiltration; Microangiopathic anemia; Thrombotic microangiopathy; Thrombotic thrombocytopenic purpura
5.  Contrast-Enhancing Meningeal Lesions Are Associated with Longer Survival in Breast Cancer-Related Leptomeningeal Metastasis 
Breast Care  2008;3(2):118-123.
Leptomeningeal metastasis (LM) is a devastating complication of advanced cancer. Despite aggressive therapy survival is very poor.
Data of all breast cancer patients with LM were retrospectively analyzed (n = 27).
Median survival was 9 weeks. Patients with contrast-enhancing meningeal lesions (n = 11) detected by MRI had a median survival of 33 weeks versus 8 weeks for patients without contrast-enhancing lesions (n = 9; p = 0.0407). Patients who received systemic chemotherapy (n = 18) had a median survival of 15 weeks versus 7 weeks (n = 9; p = 0.0106). Patients undergoing radiotherapy (n = 8) had a median survival of 17 weeks as compared to 5 weeks for patients without radiotherapy (n = 18; p = 0.0188). In a multiple Cox regression analysis, lack of systemic therapy (hazard ratio, HR 89.5; p = 0.002) and negative hormone receptor status (HR 4.2; p = 0.027) emerged as significant main risk factors, together with contrast-enhancing lesion as effect modifier for systemic therapy (p = 0.03).
Contrast-enhancing meningeal lesions, systemic therapy, and radiotherapy were significantly associated with longer survival. Patients with contrast-enhancing lesions who were treated systemically had the longest survival. Evidence is increasing that systemic therapy plays an important role and should be applied in breast cancer patients with LM.
PMCID: PMC2931086  PMID: 21373215
Breast cancer; Leptomeningeal metastases; Carcinomatous meningitis; Neoplastic meningitis; Intrathecal chemotherapy
6.  Contaminations Occurring in Fungal PCR Assays 
Journal of Clinical Microbiology  1999;37(4):1200-1202.
Successful in vitro amplification of fungal DNA in clinical specimens has been reported recently. In a collaboration among five European centers, the frequency and risk of contamination due to airborne spore inoculation or carryover contamination in fungal PCR were analyzed. The identities of all contaminants were specified by cycle sequencing and GenBank analysis. Twelve of 150 PCR assays that together included over 2,800 samples were found to be contaminated (3.3% of the negative controls were contaminated during the DNA extraction, and 4.7% of the PCR mixtures were contaminated during the amplification process). Contaminants were specified as Aspergillus fumigatus, Saccharomyces cerevisiae, and Acremonium spp. Further analysis showed that commercially available products like zymolyase powder or 10× PCR buffer may contain fungal DNA. In conclusion, the risk of contamination is not higher in fungal PCR assays than in other diagnostic PCR-based assays if general precautions are taken.
PMCID: PMC88676  PMID: 10074553

Results 1-6 (6)