Christoph Burdelski

Induction of Staphylococcus epidermidis biofilm formation via proteolytic processing of the accumulation‐associated protein by staphylococcal and host proteases

Because of its biofilm forming potential Staphylococcus epidermidis has evolved as a leading cause of device‐related infections. The polysaccharide intercellular adhesin (PIA) is significantly involved in biofilm accumulation. However, infections because of PIA‐negative strains are not uncommon, suggesting the existence of PIA‐independent biofilm accumulation mechanisms. Here we found that biofilm formation in the clinically significant S. epidermidis 5179 depended on the expression of a truncated 140 kDa isoform of the 220 kDa accumulation‐associated protein Aap. As expression of the truncated Aap isoform leads to biofilm formation in aap‐negative S. epidermidis 1585, this domain mediates intercellular adhesion in a polysaccharide‐independent manner. In contrast, expression of full‐length Aap did not lead to a biofilm‐positive phenotype. Obviously, to gain adhesive function, full‐length Aap has to be proteolytically processed through staphylococcal proteases as demonstrated by inhibition of biofilm formation by α2‐macroglobulin. Importantly, also exogenously added granulocyte proteases activated Aap, thereby inducing biofilm formation in S. epidermidis 5179 and four additional, independent clinical S. epidermidis strains. It is therefore reasonable to assume that in vivo effector mechanisms of the innate immunity can directly induce protein‐dependent S. epidermidis cell aggregation and biofilm formation, thereby enabling the pathogen to evade clearance by phagocytes.

Arterial en bloc resection for pancreatic carcinoma.

Surgery for locally advanced pancreatic cancer with arterial involvement of the hepatic artery, coeliac trunk and superior mesenteric artery (SMA) is highly controversial. In a retrospective review, the benefits and harms of arterial en bloc resection (AEBR) for pancreatic adenocarcinoma with arterial involvement were analysed.

Pathogenesis of staphylococcal device-related infections: from basic science to new diagnostic, therapeutic and prophylactic approaches

Infections associated with indwelling medical devices are a major problem in modern medicine, affecting millions of patients worldwide each year. Staphylococci, especially Staphylococcus aureus and Staphylococcus epidermidis, are the most characteristic causative organisms isolated in the context of device-related infections. The tight pathogenetic association between foreign-body implantation and staphylococcal infection is related to their capability to establish multilayered, highly structured biofilms on artificial surfaces. The ever-increasing spread of highly antibiotic-resistant staphylococci as well as the inherent resistance of biofilm-organized bacteria against antibiotics and effector mechanisms of the host immune system regularly results in failure of conventional therapeutic protocols. Research to identify novel, innovative targets for improved diagnostic, therapeutic and prophylactic approaches to the elucidation of the molecular pathogenesis of staphylococcal foreign-body-related infections has gained increasing interest over the last two decades. This review summarizes the current knowledge of staphylococcal biofilm infections and emphasizes the implications of the progress made in clinical management.

An 18 kDa Scaffold Protein Is Critical for Staphylococcus epidermidis Biofilm Formation

Virulence of the nosocomial pathogen Staphylococcus epidermidis is crucially linked to formation of adherent biofilms on artificial surfaces. Biofilm assembly is significantly fostered by production of a bacteria derived extracellular matrix. However, the matrix composition, spatial organization, and relevance of specific molecular interactions for integration of bacterial cells into the multilayered biofilm community are not fully understood. Here we report on the function of novel 18 kDa Small basic protein (Sbp) that was isolated from S. epidermidis biofilm matrix preparations by an affinity chromatographic approach. Sbp accumulates within the biofilm matrix, being preferentially deposited at the biofilm–substratum interface. Analysis of Sbp-negative S. epidermidis mutants demonstrated the importance of Sbp for sustained colonization of abiotic surfaces, but also epithelial cells. In addition, Sbp promotes assembly of S. epidermidis cell aggregates and establishment of multilayered biofilms by influencing polysaccharide intercellular-adhesin (PIA) and accumulation associated protein (Aap) mediated intercellular aggregation. While inactivation of Sbp indirectly resulted in reduced PIA-synthesis and biofilm formation, Sbp serves as an essential ligand during Aap domain-B mediated biofilm accumulation. Our data support the conclusion that Sbp serves as an S. epidermidis biofilm scaffold protein that significantly contributes to key steps of surface colonization. Sbp-negative S. epidermidis mutants showed no attenuated virulence in a mouse catheter infection model. Nevertheless, the high prevalence of sbp in commensal and invasive S. epidermidis populations suggests that Sbp plays a significant role as a co-factor during both multi-factorial commensal colonization and infection of artificial surfaces.

Cytoplasmic accumulation of Sequestosome 1 (p62) is a predictor of biochemical recurrence, rapid tumor cell proliferation and genomic instability in prostate cancer

Purpose: Sequestosome 1 (p62) is a multifunctional adapter protein accumulating in autophagy-defective cells. Experimental Design: To evaluate the clinical impact and relationship with key genomic alterations in prostate cancer, p62 protein levels were analyzed by immunohistochemistry on a tissue microarray containing 12,427 prostate cancers. Data on ERG status and deletions of PTEN, 3p13, 5q21, and 6q15 were available from earlier studies. Results: p62 immunostaining was absent in benign prostatic glands but present in 73% of 7,822 interpretable prostate cancers. Strong cytoplasmic p62 staining was tightly linked to high Gleason grade, advanced pathologic tumor (pT) stage, positive nodal status, positive resection margin, and early PSA recurrence (P < 0.0001 each). Increased levels of p62 were significantly linked to TMPRSS2–ERG fusions, both by FISH and immunohistochemical analysis (P < 0.0001 each). For example, moderate or strong p62 immunostaining was seen in 28.5% of cancers with TMPRSS2–ERG fusion detected by FISH and in 23.1% of cancers without such rearrangements (P < 0.0001). Strong p62 staining was significantly linked to the presence of all tested deletions, including PTEN (P < 0.0001), 6q15 (P < 0.0001), 5q21 (P = 0.0002), 3p13 (P = 0.0088), and 6q15 (P < 0.0001), suggesting a link between p62 accumulation and loss of genomic stability. The prognostic role of p62 protein accumulation was striking and independent of Gleason grade, pT stage, pN stage, surgical margin status, and preoperative PSA, regardless of whether preoperative or postoperative parameters were used for modeling. Conclusions: Our study identifies cytoplasmic accumulation of p62 as a strong predictor of an adverse prognostic behavior of prostate cancer independently from established clinicopathologic findings. Clin Cancer Res; 21(15); 3471–9. ©2015 AACR.

HDAC1 overexpression independently predicts biochemical recurrence and is associated with rapid tumor cell proliferation and genomic instability in prostate cancer.

Histone deacetylases (HDACs) play an important role in tumor development and progression by modifying histone and non-histone proteins. In the current study we analyzed prevalence and prognostic impact of HDAC1 in prostate cancer. HDAC1 expression was analyzed by immunohistochemistry on a tissue microarray containing more than 12,400 prostate cancer specimens. Results were compared to tumor phenotype, biochemical recurrence, and molecular subtypes defined by ERG status as well as genomic deletions of 3p, 5q, 6q and PTEN. HDAC1 immunostaining was detectable in 75.4% of 9744 interpretable cancers and considered strong in 15.4%, moderate in 39.4% and weak in 20.7% of cases. High HDAC1 expression was associated with high Gleason grade (p<0.0001), advanced pathological tumor stage (p<0.0001), positive nodal status (p=0.0010), elevated preoperative PSA-level (p=0.0127), early PSA recurrence (p<0.0001) and increased cell proliferation (p<0.0001). Moreover, high-level HDAC1 staining was associated with TMPRSS2:ERG rearrangement and ERG expression in prostate cancers (p<0.0001) and was linked to deletions of PTEN (p<0.0001), 6q (p<0.0001) and 5q (p=0.0028) in ERG-negative cancers. The prognostic impact of HDAC1 was independent of established clinicopathological parameters and was mostly driven by ERG-negative cancers as revealed by subgroup analyses. HDAC1 has strong prognostic impact in prostate cancer and might contribute to the development of a fraction of genetically instable and particularly aggressive prostate cancers. HDAC1 measurement might therefore be of clinical value for risk stratification of prostate cancer and should be further evaluated in this regard.

Perivascular epitheloid cell tumour (PEComa) of the retroperitoneum – a rare tumor with uncertain malignant behaviour: a case report

IntroductionPerivascular epitheloid cell tumours are rare mesenchymal neoplasms characterized by a proliferation of perivascular cells with an epitheloid phenotype and expression of myomelanocytic markers.Case presentationHere we present the case of a cystic perivascular epitheloid cell tumour of the retroperitoneum associated with multifocal lung lesions. A 27-year-old woman underwent laparotomy to remove a 10 × 6 × 4 cm sized retroperitoneal mass. The resected specimen was subjected to frozen and permanent histological sections with conventional and immunohistochemical stains, including antibodies against HMB45. The tumour displayed the typical morphological and immunohistochemical features of a perivascular epitheloid cell tumour. Focal necrosis and a proliferative index of 10% suggested a malignant potential. Moreover, postoperative computed tomography scans demonstrated multiple lung lesions, which were radiologically interpreted as being most likely compatible with lymphangioleiomyomatosis.ConclusionSince lymphangioleiomyomatosis, an otherwise benign condition, belongs to the family of perivascular epitheloid cell tumours, it cannot be excluded that the lung lesions in this case in fact represent metastases from the retroperitoneal perivascular epitheloid cell tumour rather than independent neoplasms. More experience with this new and unusual tumour entity is clearly needed in order to define reliable criteria for benign or malignant behaviour.

Loss of ALCAM expression is linked to adverse phenotype and poor prognosis in breast cancer: a TMA-based immunohistochemical study on 2,197 breast cancer patients.

Activated leukocyte cell adhesion molecule (ALCAM) is a membranous cell adhesion protein that is often expressed in breast cancer. Data on the prognostic impact of ALCAM expression is highly controversial in this cancer. To evaluate the clinical impact of ALCAM expression in a sufficiently large patient cohort, we utilized a tissue microarray (TMA) containing more than 2,100 primary breast cancers with clinical follow-up data by immunohistochemistry. TMA spots containing normal breast epithelium showed moderate to strong membranous ALCAM staining. ALCAM staining was strong in 66.2%, moderate in 10.9%, weak in 11.1% and absent in 11.8% of 1,778 (80.9%) interpretable breast cancer tissue spots. Decreased ALCAM expression was significantly associated with advanced tumor size (p=0.0017), unfavorable tumor grade (p<0.0001), negative ER and PR status (p<0.0001 each) as well as high Ki67 labeling index (p<0.0001). Cancers with ACLAM expression loss had a significantly poorer overall (p<0.0001) and disease-specific survival (p=0.0088). This association also held true in the subset of nodal positive cancers (p<0.0001). In conclusion, these data demonstrate that ALCAM is generally expressed in normal and cancerous breast epithelium and that a marked reduction of ALCAM expression characterizes a subset of breast cancer patients with adverse tumor characteristics and unfavorable clinical outcome.

Reduced AZGP1 expression is an independent predictor of early PSA recurrence and associated with ERG-fusion positive and PTEN deleted prostate cancers.

Zinc‐alpha 2‐glycoprotein (AZGP1) is involved in lipid metabolism and was suggested as a candidate prognostic biomarker in prostate cancer. To evaluate the clinical impact and relationship with key genomic alterations in prostate cancer, AZGP1 expression was analyzed by immunohistochemistry on a tissue microarray containing 11,152 prostate cancers. Data on ERG status and PTEN, 3p13, 5q21 and 6q15 deletions were available from earlier studies. AZGP1 expression was strong in benign prostatic glands but absent in 38.0% of 8,510 interpretable prostate cancers. Reduced AZGP1 expression was associated with TPMRSS2:ERG fusions, both by FISH and immunohistochemical analysis (p < 0.0001 each). For example, AZGP1 was absent in 54.6% of 2,029 ERG IHC positive but in only 28.1% of 2,398 ERG negative cancers. Irrespective of the ERG status, reduced AZGP1 expression was tightly linked to high Gleason score, advanced pathological tumor stage, positive nodal status and early PSA recurrence (p < 0.0001 each). Reduced AZGP1 expression was also strongly associated with PTEN deletions. AZGP1 immunostaining was lacking in 62.7% of 842 PTEN deleted but in only 37.3% of PTEN non‐deleted cancers but retained strong prognostic influence in both subgroups (p < 0.0001 each). The prognostic role of AZGP1 expression was also independent of Gleason score, pT stage, pN stage, surgical margin status and preoperative PSA, irrespective of whether preoperative or postoperative variables were used for modeling. In conclusion, the results of our study demonstrate that reduced AZGP1 expression is strongly related to adverse prostate cancer prognosis, independently of established clinic‐pathological variables and PTEN deletions.

Loss of SOX9 Expression Is Associated with PSA Recurrence in ERG-Positive and PTEN Deleted Prostate Cancers

The transcription factor SOX9 plays a crucial role in normal prostate development and has been suggested to drive prostate carcinogenesis in concert with PTEN inactivation. To evaluate the clinical impact of SOX9 and its relationship with key genomic alterations in prostate cancer, SOX9 expression was analyzed by immunohistochemistry on a tissue microarray containing 11,152 prostate cancers. Data on ERG status and deletions of PTEN, 3p13, 5q21 and 6q15 were available from earlier studies. SOX9 expression levels were comparable in luminal cells of normal prostate glands (50% SOX9 positive) and 3,671 cancers lacking TMPRSS2:ERG fusion (55% SOX9 positive), but was markedly increased in 3,116 ERG-fusion positive cancers (81% SOX9 positive, p<0.0001). While no unequivocal changes in the SOX9 expression levels were found in different stages of ERG-negative cancers, a gradual decrease of SOX9 paralleled progression to advanced stage, high Gleason grade, metastatic growth, and presence of PTEN deletions in ERG-positive cancers (p<0.0001 each). SOX9 levels were unrelated to deletions of 3p, 5q, and 6q. Down-regulation of SOX9 expression was particularly strongly associated with PSA recurrence in ERG-positive tumors harboring PTEN deletions (p=0.001), but had no significant effect in ERG-negative cancers or in tumors with normal PTEN copy numbers. In summary, the results of our study argue against a tumor-promoting role of SOX9 in prostate cancer, but demonstrate that loss of SOX9 expression characterizes a particularly aggressive subset of ERG positive cancers harboring PTEN deletions.