[Show abstract][Hide abstract] ABSTRACT: About 40% of clear-cell renal cell carcinomas (ccRCC) harbor mutations in Polybromo-1 (PBRM1), encoding the BAF180 subunit of a SWI/SNF chromatin remodeling complex. This qualifies PBRM1 as a major cancer gene in ccRCC. The PBRM1 protein alters chromatin structure and its known functions include transcriptional regulation by controlling the accessibility of DNA and influencing p53 transcriptional activity. Since little is known about regulation of PBRM1, we studied possible mechanisms and interaction partners involved in the regulation of PBRM1 expression. Activation of p53 in RCC cells resulted in a marked decrease of PBRM1 protein levels. This effect was abolished by siRNA-mediated down regulation of p53, and transcriptional activity was not crucial for p53-dependent PBRM1 regulation. Pulse-chase experiments determined post-translational protein degradation to be the underlying mechanism for p53-dependent PBRM1 regulation, which was accordingly inhibited by proteasome inhibitors. The effects of p53 activation on PBRM1 expression were confirmed in RCC tissue ex vivo. Our results demonstrate that PBRM1 is a target of p53-induced proteasomal protein degradation and provide further evidence for the influence of PBRM1 on p53 function in RCC tumor cells. Considering the paramount role of p53 in carcinogenesis and the presumptive impact of PBRM1 in RCC development, this novel regulation mechanism might be therapeutically exploited in the future.
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The Journal of Pathology 07/2015; DOI:10.1002/path.4592 · 7.43 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: For desensitization of ABO-incompatible kidney transplant recipients we recently proposed nonantigen-specific immunoadsorption (IA) and rituximab.
We now compared clinical outcomes of 34 ABO-incompatible living-donor kidney recipients who were transplanted using this protocol with that of 68 matched ABO-compatible patients. In addition, we analyzed efficacy and cost of nonantigen-specific as compared to blood group antigen-specific IA.
Before desensitization, the median isoagglutinin titer of 34 ABO-incompatible patients was 1:64 (Coombs technique). Patients received a median of 7 preoperative IA treatments. Twenty-four patients had a median of 2 additional plasmapheresis treatments to reach the preoperative target isoagglutinin titer of 1:8 or less. After a median postoperative follow-up of 22 months, overall graft survival in the ABO-incompatible group was not significantly different from that in ABO-compatible patients (log-rank P = 0.20), whereas patient survival tended to be lower (log-rank P = 0.05). The incidence of rejection episodes was 15% in both groups. The ABO-incompatible kidney recipients had a higher incidence of BK virus replication (P = 0.04) and nephropathy (P = 0.01) and showed more often colonization with multidrug resistant bacteria (P = 0.02). In comparison to blood group antigen-specific IA, nonantigen-specific IA showed equal efficacy but was associated with reduction in cost.
Clinical outcomes of ABO-incompatible patients desensitized with a nonantigen-specific IA device and rituximab do not differ from that of matched ABO-compatible patients although a trend toward reduced patient survival was noted. Special attention must be paid to the higher incidence of BK virus infection in recipients of ABO-incompatible grafts.
[Show abstract][Hide abstract] ABSTRACT: Objectives
To evaluate CD24/CD44/CD47 cancer stem cell marker expressions in bladder cancer (BCa) and provide data on their prognostic significance for clinical outcome in patients undergoing radical cystectomy (RC).
Material and methods
Primary BCa tissue was used for xenograft studies. A tissue microarray was prepared using specimens from a cohort of 132 patients. All patients underwent RC for urothelial BCa between 2001 and 2010. Expression of CD24, CD44, and CD47 was examined in primary samples and xenografts by fluorescence-activated cell sorting. Populations of CD24low- and CD24high- expressing cells were sorted and evaluated for tumorigenicity in vivo. Tissue microarray was analyzed for CD24/CD44 staining intensity and tumor-specific vs. stromal cell staining. Associations with BCa survival, BCa stage, and lymph node status were evaluated by univariate and multivariate analyses.
CD24 and CD44/CD47 expressions mark distinct cell populations within the normal urothelium as well as in BCa. CD24high/low expression was not sufficient to characterize CD24 as a BCa-initiating marker in in vivo primary xenotransplants. CD24 and CD44 expressions correlated with lower cancer-specific survival in patients. However, multivariate analyses of CD24 or CD44 did not demonstrate significantly increased hazards for cancer-specific death if analyzed together with stage, grade, and nodal status of patients.
Cancer stem cell markers CD24/CD44/CD47 are differentially expressed in cells of urothelial BCa in patients undergoing RC and influence cancer-specific survival of patients. Further evaluation of CD24/CD44/CD47 protein expression could be of high therapeutic value in BCa. However, both CD24 and CD44 expressions cannot be regarded as independent prognostic parameters for patients undergoing RC.
[Show abstract][Hide abstract] ABSTRACT: Overexpression of Decoy Receptor 3 (DcR3), a soluble member of the tumor necrosis factor receptor superfamily, is a common event in several types of cancer. In renal cell carcinoma (RCC), DcR3 overexpression is associated with lymph node and distant metastasis as well as a poor prognosis. However, the functional role and regulation of DcR3 expression in RCC is so far unknown.
Modulation of DcR3 expression by siRNA and ectopic gene expression, respectively, was performed in ACHN and 769-P RCC cell lines. Functional effects of a modulated DcR3 expression were analyzed with regard to migration, invasion, adhesion, clonogenicity, and proliferation. Furthermore, quantitative RT-PCR and immunoblot analyses were performed to evaluate the expression of downstream mediators of DcR3. In further experiments, luciferase assays, quantitative RT-PCR and immunoblot analyses were applied to study the regulation of DcR3 expression in RCC. Additionally an ex vivo tissue slice culture technique combined with immunohistochemistry was used to study the regulation of DcR3 expression in human RCC specimen.
Here, we show that DcR3 promotes adhesion, migration and invasiveness of RCC cells. The DcR3-dependent increase in cellular invasiveness is accompanied with an up-regulation of integrin alpha 4, matrixmetalloproteinase 7 and urokinase plasminogen activator (uPA). Further, we identified a signaling pathway regulating DcR3 expression in RCC. Using in vitro experiments as well as an ex vivo RCC tissue slice culture model, we demonstrate that expression of DcR3 is regulated in a PI3K/AKT-dependent manner involving the transcription factor nuclear factor of activated T-cells (NFAT).
Taken together, our results identify DcR3 as a key driver of tumor cell dissemination and suggest DcR3 as a promising target for rational therapy of RCC.
Molecular Cancer 10/2013; 12(1):120. DOI:10.1186/1476-4598-12-120 · 4.26 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Mutations of the von Hippel-Lindau (VHL) tumor suppressor gene cause hereditary and sporadic renal cell carcinomas (RCCs). The best characterized function of VHL protein is suppression of the α subunit of hypoxia inducible factor (HIF). Additional VHL functions have been reported, including induction of senescence upon loss of VHL mediated by downregulation of the chromatin remodeling factor p400. Induction of senescence either by oncogene activation or inactivation of tumor suppressors is considered a critical feature of mammalian cells by which to suppress tumorigenesis. In the present study, we investigated the relationship between the expression of p400 and patient survival following RCC diagnosis taking advantage of a large and well-documented series of RCC patients with long-term follow-up information. The expression of p400 was measured by immunohistochemistry using a tissue microarray containing tumor tissue samples from 868 RCC patients. Chi-squared tests, Kaplan-Meier curves, Cox regression models and Spearman's rank correlation estimates were used to investigate the possible relationship between p400 expression and Ki-67 proliferative index, clinical and pathological characteristics and patient survival. Complete loss of p400 expression was detected in 64% of all tumor specimens, and decreased p400 expression was associated with advanced tumor stage, higher grade of malignancy and regional lymph node metastasis. Among well-differentiated RCCs, high proliferation (Ki-67 index >10) was found in 12% of carcinomas with an increased p400 expression, compared to 5% of RCCs with decreased p400 expression. Multiple Cox regression indicated that patients with low proliferative tumors and increased p400 expression had a 60% lower cancer-specific mortality risk compared to those affected by low proliferative RCCs with decreased p400 expression. In summary, patients affected by highly proliferative tumors with decreased p400 expression exhibit a poor prognosis by multiple Cox regression. Our data suggest that the highly proliferative, decreased-p400 subgroup of RCCs represents tumors that are characterized by a loss of the tumor-suppressive mechanism of senescence.
[Show abstract][Hide abstract] ABSTRACT: For rare cancers such as neuroendocrine bladder cancer (NEBC) treatment options are limited, partly due to lack of pre-clinical models. Techniques to amplify rare primary NEBC cells could provide novel tools for the discovery of drug- and diagnostic targets. We aimed to develop preclinical experimental models for NEBC.
Fresh tumor tissue from two NEBC patients was used to establish in vitro and in vivo models. Additional archived tissues from NEBC-patients were analyzed from the National Center of Tumor Diseases tissue bank. Primary tumor samples were collected during radical cystectomy. For inhibition of MET in animal models and cell culture PHA-665752 was used. Expression of markers and drug targets on NEBC were determined by flow cytometry. Growth of NEBC in vitro was determined by counting live cells. Tumor growth in mice was assessed by measuring tumor volume. Comparison between groups was done using non-parametric Kruskal-Wallis tests.
Xenograft models and serum-free cultures of NEBC cells allowed screening for cell surface markers and drug targets. We found expression of the HGF-receptor MET on NEBC cultures, xenograft models and in primary patient sections. Growth of NEBC spheroids in vitro critically depended on HGF. Treatment of NEBC-bearing mice with a MET-inhibitor significantly decreased tumor growth compared to control-treated mice.
Establishment of NEBC xenografts and serum-free cultures provided suitable models to identify diagnostic markers and therapeutic targets. Using such a model we can demonstrate HGF dependent growth of human NEBC and identify MET as a new treatment target for NEBC.
The Journal of urology 06/2013; 190(6). DOI:10.1016/j.juro.2013.06.053 · 4.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Circulating soluble urokinase receptor (suPAR) was recently identified as one of the causes responsible for native and recurrent focal segmental glomerulosclerosis (FSGS) through overactivation of podocyte β3 integrin. Here, we discuss the management of a patient with very high suPAR serum levels and FSGS recurrence. The suPAR reduction using plasmapheresis and immunoadsorption allowed for lowering of suPAR and reduced podocyte β3 integrin activation and proteinuria. The patient is successfully weaned to bimonthly suPAR removal treatments with improved renal parameters. In summary, we provide an approach for the successful management of severe recurrent FSGS using available therapies with biomarker guidance.
American journal of therapeutics 03/2013; 20(2):226-9. DOI:10.1097/MJT.0b013e3182811aca · 1.13 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Due to increasing waiting times for deceased donor kidneys, living donor kidney transplantation is increasingly performed in the presence of donor-specific antibodies (DSA).
Twenty-three patients with Luminex-detected DSA were successfully desensitized by anti-CD20 therapy and immunoadsorption (N = 19) or plasmapheresis (N = 4) and received a kidney transplant from a living donor. Twelve of the 23 patients (52%) had a positive CDC and/or ELISA crossmatch result before desensitization. Six patients were negative in CDC as well as ELISA screening but positive in Luminex for DSA.
The 23 patients received a median of 8 apheresis treatments before and 5 treatments after transplantation. Induction therapy was performed with either thymoglobulin (N = 11) or basiliximab (N = 12). The 2-year graft survival rate was 100%. At last follow up, a median of 12 months after transplantation, median serum creatinine was 1.42 mg/dL, median MDRD-GFR 59.5 mL/min/1.73 m(2), and median urinary protein-to-creatinine ratio 0.12. Ten out of fourteen patients (71%) who had completed the first year after transplantation by the time of analysis had no DSA by day 360. Acute T-cell mediated rejection was diagnosed in one patient (4%), and antibody-mediated changes were found in 5 patients (22%). Four out of these 5 patients showed evidence of persistent (N = 2) or reemerging plus/minus de novo DSA (N = 2) on day 360, and the 2 patients with persistent DSA lost their allograft subsequently on days 750 and 810, respectively. Infectious complications were infrequent.
Our previously described treatment algorithm for desensitization of living donor kidney transplant recipients with DSA results in good graft outcomes with a low rate of side effects.
[Show abstract][Hide abstract] ABSTRACT: Background:
The B-cell translocation gene 2 (BTG2) is considered to act as a tumour-suppressor gene because of its antiproliferative and antimigratory activities. Higher levels of BTG2 expression in tumour cells have been linked to a better clinical outcome for several cancer entities. Here, we investigated the expression and function of BTG2 in bladder cancer.
The expression of BTG2 in bladder cancer cells was silenced by RNA interference. Cell motility was investigated by wound healing and Boyden chamber assays. The protein expression of BTG2 in bladder cancer was studied by immunohistochemistry.
We observed that targeted suppression of BTG2 by RNA interference did not result in growth stimulation but led to a substantial inhibition of bladder cancer cell motility. Tissue microarray analyses of bladder cancer cystectomy specimens revealed that higher BTG2 expression levels within the tumours correlated strongly with a decreased cancer-specific survival for bladder cancer patients.
These results indicate that endogenous BTG2 expression contributes to the migratory potential of bladder cancer cells. Moreover, high levels of BTG2 in bladder cancers are linked to decreased cancer-specific survival. These findings question the conception that BTG2 generally acts as a tumour suppressor and typically represents a favourable clinical marker for cancer patients.
British Journal of Cancer 01/2013; 108(4). DOI:10.1038/bjc.2012.573 · 4.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective:
The aim of this study was to evaluate the prognostic relevance of melanoma-associated antigen (MAGE) A9 in renal cell carcinoma (RCC).
Material and methods:
Immunohistochemical staining for MAGE A9 was evaluated in a tissue microarray containing 587 RCC tumour tissue samples. Nuclear MAGE A9 expression was reviewed using a semiquantitative score. Follow-up has been surveyed since 1990 in a prospectively conducted tumour database. The effect of MAGE A9 expression on cancer-specific survival (CSS) was assessed by univariate and multivariate Cox regression analyses. Subgroup analyses were performed for non-metastatic and metastatic disease.
Median age in all patients was 63.2 years, 354 patients were male and 233 female, and 108 patients had metastatic disease. Median follow-up was 5.6 years for all patients and 9.0 years for patients still alive (range 0-19.9 years). High nuclear MAGE A9 expression was present in 326 tumour specimens (55.5%). In multivariate analyses high nuclear MAGE A9 expression was associated with poor CSS (p = 0.0027). Furthermore, tumour stage, lymph-node and distant metastasis, Fuhrman grade G3/4, Karnofsky index < 80% and male gender were associated with poor CSS. In subgroup analyses, results were concordant for patients with non-metastatic disease. In patients with metastatic disease, only Karnofsky index > 80% was a significant predictor for CSS; MAGE A9 expression could not be shown to be associated with CSS (p = 0.161).
High nuclear MAGE A9 expression is independently associated with poor CSS in patients with non-metastatic RCC. The assessment of MAGE A9 expression can provide additional prognostic information and should be used in decision-making regarding adjuvant therapy in patients with non-metastatic disease.
Scandinavian Journal of Urology and Nephrology 11/2012; 47(4). DOI:10.3109/00365599.2012.740070 · 1.24 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Purpose:
During kidney transplantation (KTx), the length of cold ischemia time (CIT) and the subsequent changes in energy metabolism may lead to variations in interstitial metabolites. Using microdialysis (MD), we evaluated the effects of a short and long CIT on changes of these metabolites.
Sixteen pigs were randomized in two identical groups, one with a short CIT and the other one with a long CIT. Using MD in the transplanted grafts, we evaluated the parenchyma concentrations of glucose, lactate, pyruvate, glutamate and glycerol in different stages.
We noted that during the warm ischemia time (WIT) and in the early post-reperfusion phase glucose levels increased more significantly in the long CIT group and remained high until the end of monitoring. At the end of CIT and during WIT, the long CIT group had a significantly higher glycerol level, but the level dropped gradually in the late post-reperfusion phase and reached a steady state in both groups.
The extended CIT clearly results in considerably impaired graft metabolism. The high interstitial glucose levels within hours after KTx could be considered as a marker of primary delayed function of the graft. Furthermore, the glycerol value could reflect the extent of graft injury during the ischemia time or in case of acute impairment of graft perfusion.
Langenbeck s Archives of Surgery 10/2012; 398(1). DOI:10.1007/s00423-012-1010-0 · 2.19 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: ABO-incompatible kidney transplantation performed after desensitization with antigen-specific immunoadsorption (IA) results in good outcomes. However, a unique single-use IA device is required, which creates high costs.
From August 2005 to August 2010, 19 patients were desensitized for ABO-incompatible living donor kidney transplantation. Six patients treated with a single-use antigen-specific IA device and 12 patients treated with a reusable non-antigen-specific IA device were analyzed.
Six patients who received antigen-specific IA had a median of 5 IA treatments and 12 patients with non-antigen-specific IA had a median of 6 IA treatments preoperatively. Median average titer drop in Coombs technique was 1.2 in antigen-specific IA and 1.7 in non-antigen-specific IA. In two patients with antigen-specific IA and four patients with non-antigen-specific IA, additional plasmapheresis treatments were necessary for recipient desensitization. Despite six treatments with antigen-specific IA and 12 plasmapheresis treatments, one patient with a starting isoagglutinin titer of 1:1024 (Coombs) could not be transplanted. The 18-month graft survival rate for the 17 ABO-incompatible living donor kidney transplants was 100%. One male recipient who was desensitized with antigen-specific IA died 44 months after transplantation from sudden cardiac death with a serum creatinine of 1.2 mg/dL. At last follow-up, a median of 13 months after transplantation, median serum creatinine for 16 patients was 1.5 mg/dL, median glomerular filtration rate as estimated by the modification of diet in renal disease formula 54 mL/min/1.73 m, and median urinary protein-to-creatinine ratio 0.1, with no differences between treatments.
A reusable non-antigen-specific IA device allows high number of treatments at reasonable cost, and at the same time might deplete human leukocyte antigen-alloantibodies.
[Show abstract][Hide abstract] ABSTRACT: Living donor kidney transplantation in crossmatch-positive patients is a challenge that requires specific measures. Ten patients with positive crossmatch results (n = 9) or negative crossmatch results but strong donor-specific antibodies (DSA; n = 1) were desensitized using immunoadsorption (IA) and anti-CD20 antibody induction. IA was continued after transplantation and accompanied by HLA antibody monitoring and protocol biopsies. After a median of 10 IA treatments, all patients were desensitized successfully and transplanted. Median levels of mean fluorescence intensity (MFI) of Luminex-DSA before desensitization were 6203 and decreased after desensitization and immediately before transplantation to 891. Patients received a median of seven post-transplant IA treatments. At last visit, after a median follow-up of 19 months, 9 of 10 patients had a functioning allograft and a median Luminex-DSA of 149 MFI; serum creatinine was 1.6 mg/dl, and protein to creatinine ratio 0.1. Reversible acute antibody-mediated rejection was diagnosed in three patients. One allograft was lost after the second post-transplant year in a patient with catastrophic antiphospholipid syndrome. We describe a treatment algorithm for desensitization of living donor kidney transplant recipients that allows the rapid elimination of DSA with a low rate of side effects and results in good graft outcome.
Transplant International 02/2012; 25(5):506-17. DOI:10.1111/j.1432-2277.2012.01447.x · 2.60 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In a nude mouse model of colorectal liver metastases, we have identified a paracrine tumor cell/host cell signalling pathway that is apparently required for successful tumor growth. Whereas recombinant platelet derived growth factor-C (PDGF-C) and supernatants from PDGF-C secreting wild type LS174T colon carcinoma cells could rescue tumor promoting hepatic stellate cells (HSC) from growth inhibition by serum starvation, supernatants from LS174T colon carcinoma cells with reduced secretion of PDGF-C had much less effect on serum starved HSC. Autocrine growth inhibition of LS174T cells by PDGF-C knock-down was only marginal. In vivo, a prominent inhibition of liver metastasis was observed if PDGF-C was knocked-down in LS174T cells. By whole genome array analysis of host cells of the invasion front and subsequent immunohistochemical staining we identified p21 activated kinase-2 (PAK-2) as being strongly and specifically expressed by HSC. The above described effect of PDGF-C on HSC was found to be dependent on PAK-2 because in contrast to wild type HSC, silencing of PAK-2 in HSC only allowed for a partial PDGF-C-mediated rescue from serum starvation leading to only a slight increase of proliferation. These data indicate that PDGF-C promotes tumor growth via a growth promoting effect on HSC that is at least in part dependent on the presence of functional PAK-2.
[Show abstract][Hide abstract] ABSTRACT: Renal cell carcinomas associated with Xp11.2 translocations have recently been identified as a distinct biological entity. The translocation results in the fusion of the transcription factor TFE3 to one of several different fusion partners including PRCC, PSF, NONO, ASPL or CTLC with consecutive overexpression of the chimeric protein. As the true frequency of these neoplasms as well as the biological properties of TFE3 activation in renal cell carcinomas are largely unknown, we have examined TFE3 expression as well as the underlying genetic alterations in a large, hospital-based series of renal cell carcinomas with long-term follow-up information. Out of a total of 876 tumours, TFE3 translocations were detected in five cases (0.6%). Three additional cases were identified in a second series of cases comprising of renal cell carcinomas developing in patients before the age of 50. However, using immunohistochemistry, 9% of all renal cell carcinomas showed some degree of TFE3 reactivity. Interestingly, these cases were associated with high nuclear grade, greater tumour extent and metastatic disease as well as an unfavourable patient outcome on uni- and multivariate analysis. Fluorescence in situ hybridisation (FISH) revealed TFE3 amplifications as an additional, novel mechanism leading to increased TFE3 expression levels. In conclusion, our data show that Xp11 translocation renal cell carcinomas are uncommon tumours accounting for <1% of adult renal cell carcinomas and that the diagnosis of Xp11 translocation renal cell carcinomas needs to be verified using molecular techniques. In turn, TFE3 overexpressing tumours show an aggressive behaviour and Xp11 translocation is only one of several possible underlying genomic alterations.
Modern Pathology 02/2012; 25(2):308-15. DOI:10.1038/modpathol.2011.169 · 6.19 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Lipid droplets (LDs) are dynamic storage compartments for energy-rich fats that are nearly ubiquitously present in eukaryotic cells, exerting tissue-specific functions in metabolically active cell types, and are increased in conditions following cellular damage or lipid overload. The LD–cytoplasm interface is stabilized by amphiphilic proteins of the PAT/perilipin family (perilipin/perilipin-1, adipophilin/perilipin-2, and TIP47/perilipin-3). We evaluated the value of adipophilin immunohistochemistry for the diagnosis of diseases associated with LD accumulation.
In human tissues, adipophilin-positive LDs were especially prominent in steroidogenic cells of the adrenal gland, testis, and ovary, in hepatocytes and hepatic stellate cells, in cardiac, striated and smooth myocytes, in lactating mammary gland epithelial cells, and in plurivacuolar adipocytes. Variable amounts of adipophilin-positive LDs were also detected almost ubiquitously in epithelial cells of the gastrointestinal tract and skin. In diseases associated with lipid storage, adipophilin was strongly expressed in lipid-laden macrophages in atherosclerosis, in cardiomyopathies, kidney diseases, hepatocyte steatosis, colon ischaemia, and at the border of organ infarcts.
Adipophilin immunohistochemistry visualizes small LDs in tissues under physiological and disease conditions that are not visible by conventional light microscopy. Immunohistology for adipophilin may facilitate histomorphological diagnosis of diseases and definition of the extent of metabolic dysregulation, such as in organ infarcts, cardiomyopathies, kidney diseases, and microvesicular steatosis.