Julia Müller

ERG Status Is Unrelated to PSA Recurrence in Radically Operated Prostate Cancer in the Absence of Antihormonal Therapy

Purpose: About 50% of prostate cancers have TMPRSS2–ERG fusions with concurrent ERG overexpression. The aim of this study was to determine whether clinical differences exist between ERG-positive and ERG-negative cancers in surgically treated patients not exposed to antihormonal therapy. A secondary aim was to search for differences between these tumor classes. Experimental Design: A tissue microarray containing samples from more than 2,800 prostate cancers with clinical data was analyzed for ERG alterations by immunohistochemistry and FISH. Results were compared with tumor phenotype, biochemical recurrence, and molecular features considered important for prostate cancer. The effect of ERG on androgen receptor (AR)-dependent transcription was analyzed in cell lines. Results: ERG expression was found in 52.4% of 2,805 cancers with a 95% concordance between ERG expression and ERG gene rearrangement detected by FISH. ERG expression was unrelated to clinical outcome and tumor phenotype. Differences in AMACR, Annexin A3, Bcl2, CD10, ALCAM, chromogranin A, epidermal growth factor receptor, HER2, mTOR, p53, and synaptophysin status were significant but minimal in absolute numbers. The most striking difference was found for AR expression, which was markedly higher in ERG-positive cancers. In vitro studies showed ERG-dependent impairment of AR-mediated transcriptional activity. Conclusions: The striking similarities between these two types of prostate cancers rules out a major impact of ERG on tumor aggressiveness in early, not hormonally treated cancer. The marked difference in AR levels between ERG-positive and -negative cancers supports a systematic difference in potential response to hormonal therapy as previously observed in clinical trials. Clin Cancer Res; 17(18); 5878–88. ©2011 AACR.

Reduced Cisplatin Sensitivity of Head and Neck Squamous Cell Carcinoma Cell Lines Correlates with Mutations Affecting the COOH-Terminal Nuclear Localization Signal of p53

Purpose: Head and neck squamous cell carcinomas (HNSCC) are the most frequent malignancies of the upper aerodigestive tract. Cisplatin resistance is a major problem in the treatment of a large number of HNSCC cancer patients. In this study, nine randomly selected HNSCC cell lines were investigated regarding expression, presence of mutations, nucleocytoplasmic distribution of p53, and sensitivity to cisplatin. Experimental Design: Protein expression was evaluated by Western blot analysis. The whole open reading frame of p53 was determined by reverse transcription-PCR sequencing. Nucleocytoplasmic distribution was evaluated by confocal laser scanning microscopy. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide viability assay was used to test for cisplatin sensitivity. Results: p53 mutations were found in all nine investigated HNSCC cell lines. Nuclear p53 signal was detected in six cell lines, whereas three cell lines exhibited total loss of nuclear p53 signal. Nuclear signal depended on the presence or absence of the COOH-terminal nuclear localization signal in p53. Cisplatin sensitivity was highly reduced in the group with loss of nuclear p53 signal compared with those with detectable nuclear signal. Transfection of wild-type and mutant p53 into a rat embryonic cell system showed highly reduced activity of the nuclear localization signal mutant p53 protein. Conclusion: Taken together, these data suggest that “loss of nuclear p53 signal” correlates with cisplatin resistance in HNSCC. If these results can be validated on a larger number of tumor samples, including fresh tumor tissues, it potentially could help in sparing a subgroup of HNSCC patients the side effects associated with unnecessary chemotherapy by identifying cisplatin nonresponders before chemotherapy induction.

Loss of pSer2448-mTOR expression is linked to adverse prognosis and tumor progression in ERG-fusion-positive cancers.

Prevalence and clinical significance of mammalian target of rapamycin (mTOR) phosphorylation at the serine 2448 is disputed in prostate cancer. A tissue microarray containing 3,261 prostate cancers and 49 normal prostate samples with clinical follow‐up data was analyzed for pSer2448‐mTOR expression by immunohistochemistry. Moderate to strong pSer2448‐mTOR staining was found in all (n = 49) normal prostate tissues, but was lost in 24% or weak in 29% cancers. Moderate and strong staining was found in 36 and 11% of tumors. Loss of pSer2448‐mTOR staining was significantly linked to advanced stage (p = 0.0027), high‐grade (p = 0.0045), nodal positive cancers (p = 0.0483), early tumor recurrence (p < 0.0001, independently from stage and grade, p = 0.0016), lack of Ets‐related gene (ERG) fusion (p < 0.0001), reduced androgen receptor expression (p < 0.0001 each) and increased cell proliferation (p = 0.0092) in all cancers and in the subset of ERG‐fusion‐positive cancers. Loss of pSer2448‐mTOR expression was linked to tumor metastasis (p = 0.0275) in ERG‐fusion‐positive cancers only. Molecular subset analysis using pre‐existing phosphatase and tensin homolog (PTEN) deletion data revealed that loss of pSer2448‐mTOR expression is of prognostic relevance and defines a subpopulation of PTEN‐deleted and ERG‐fusion‐positive cancers with a particular poor outcome. The results of our study strongly suggest that loss of pSer2448‐mTOR expression is a marker for activated AKT/mTOR signaling. Tumors with concomitant PTEN deletion and activated mTOR signaling indicated by loss of pSer2448‐mTOR expression characterize a small (4%) but clinically significant subset of prostate cancers that might optimally benefit from anti‐mTOR therapies.

Pivotal Role of Phospholipase D1 in Tumor Necrosis Factor-α–Mediated Inflammation and Scar Formation after Myocardial Ischemia and Reperfusion in Mice

Myocardial inflammation is critical for ventricular remodeling after ischemia. Phospholipid mediators play an important role in inflammatory processes. In the plasma membrane they are degraded by phospholipase D1 (PLD1). PLD1 was shown to be critically involved in ischemic cardiovascular events. Moreover, PLD1 is coupled to tumor necrosis factor-α signaling and inflammatory processes. However, the impact of PLD1 in inflammatory cardiovascular disease remains elusive. Here, we analyzed the impact of PLD1 in tumor necrosis factor-α-mediated activation of monocytes after myocardial ischemia and reperfusion using a mouse model of myocardial infarction. PLD1 expression was highly up-regulated in the myocardium after ischemia/reperfusion. Genetic ablation of PLD1 led to defective cell adhesion and migration of inflammatory cells into the infarct border zone 24 hours after ischemia/reperfusion injury, likely owing to reduced tumor necrosis factor-α expression and release, followed by impaired nuclear factor-κB activation and interleukin-1 release. Moreover, PLD1 was found to be important for transforming growth factor-β secretion and smooth muscle α-actin expression of cardiac fibroblasts because myofibroblast differentiation and interstitial collagen deposition were altered in Pld1(-/-) mice. Consequently, infarct size was increased and left ventricular function was impaired 28 days after myocardial infarction in Pld1(-/-) mice. Our results indicate that PLD1 is crucial for tumor necrosis factor-α-mediated inflammation and transforming growth factor-β-mediated collagen scar formation, thereby augmenting cardiac left ventricular function after ischemia/reperfusion.

Deletion of Hyaluronan Synthase 3 Inhibits Neointimal Hyperplasia in Mice

Objective— Hyaluronan (HA) is a polymeric glucosaminoglycan that forms a provisional extracellular matrix in diseased vessels. HA is synthesized by 3 different HA synthases (HAS1, HAS2, and HAS3). Aim of this study was to unravel the role of the HAS3 isoenzyme during experimental neointimal hyperplasia. Approach and Results— Neointimal hyperplasia was induced in Has3-deficient mice by ligation of the carotid artery. HA in the media of Has3-deficient mice was decreased 28 days after ligation, and neointimal hyperplasia was strongly inhibited. However, medial and luminal areas were unaffected. Cell density, proliferation, and apoptosis were not altered, suggesting a proportional decrease of both, the number of cells and extracellular matrix. In addition, endothelial function as determined by acetylcholine-induced relaxation of aortic rings, immunoblotting of endothelial nitric oxide synthase, and arterial blood pressure were not affected. Furthermore, the oxidative stress response was not affected as determined in total protein extracts from aortae. Transcriptome analysis comparing control versus ligated carotid arteries hinted toward a mitigated differential regulation of various signaling pathways in Has3-deficient mice in response to ligation that were related to vascular smooth muscle cell (VSMC) migration, including focal adhesions, integrins, mitogen-activated protein kinase, and phosphatidylinositol signaling system. Lentiviral overexpression of HAS3 in VSMC supported the migratory phenotype of VSMC in response to platelet-derived growth factor BB in vitro. Accordingly, knockdown of HAS3 reduced the migratory response to platelet-derived growth factor BB and in addition decreased the expression of PDGF-B mRNA. Conclusions— HAS3-mediated HA synthesis after vessel injury supports seminal signaling pathways in activation of VSMC, increases platelet-derived growth factor BB–mediated migration, and in turn enhances neointimal hyperplasia in vivo.

Loss of Biglycan Enhances Thrombin Generation in Apolipoprotein E-Deficient Mice: Implications for Inflammation and Atherosclerosis.

Objective— Thrombin signaling promotes atherosclerosis by initiating inflammatory events indirectly through platelet activation and directly via protease-activated receptors. Therefore, endogenous thrombin inhibitors may be relevant modulators of atheroprogression and cardiovascular risk. In addition, endogenous thrombin inhibitors may affect the response to non–vitamin K-dependent oral anticoagulants. Here, the question was addressed whether the small leucine-rich proteoglycan biglycan acts as an endogenous thrombin inhibitor in atherosclerosis through activation of heparin cofactor II. Approach and Results— Biglycan concentrations were elevated in the plasma of patients with acute coronary syndrome and in male Apolipoprotein E -deficient ( ApoE −/−) mice. Biglycan was detected in the glycocalyx of capillaries and the subendothelial matrix of arterioles of ApoE −/− mice and in atherosclerotic plaques. Thereby a vascular compartment is provided that may mediate the endothelial and subendothelial activation of heparin cofactor II through biglycan. ApoE and Bgn double-deficient ( ApoE −/− /Bgn −/0) mice showed higher activity of circulating thrombin, increased platelet activation and platelet adhesion in vivo, supporting a role of biglycan in balancing thrombin activity. Furthermore, concentrations of circulating cytokines and aortic macrophage content were elevated in ApoE −/− /Bgn −/0 mice, suggesting a proinflammatory phenotype. Elevated platelet activation and macrophage accumulation were reversed by treating ApoE −/− /Bgn −/0 mice with the thrombin inhibitor argatroban. Ultimately, ApoE −/− /Bgn −/0 mice developed aggravated atherosclerosis. Conclusions— The present results indicate that biglycan plays a previously unappreciated protective role during the progression of atherosclerosis by inhibiting thrombin activity, platelet activation, and finally macrophage-mediated plaque inflammation. # Significance {#article-title-44}Objective—Thrombin signaling promotes atherosclerosis by initiating inflammatory events indirectly through platelet activation and directly via protease-activated receptors. Therefore, endogenous thrombin inhibitors may be relevant modulators of atheroprogression and cardiovascular risk. In addition, endogenous thrombin inhibitors may affect the response to non–vitamin K-dependent oral anticoagulants. Here, the question was addressed whether the small leucine-rich proteoglycan biglycan acts as an endogenous thrombin inhibitor in atherosclerosis through activation of heparin cofactor II. Approach and Results—Biglycan concentrations were elevated in the plasma of patients with acute coronary syndrome and in male Apolipoprotein E-deficient (ApoE−/−) mice. Biglycan was detected in the glycocalyx of capillaries and the subendothelial matrix of arterioles of ApoE−/− mice and in atherosclerotic plaques. Thereby a vascular compartment is provided that may mediate the endothelial and subendothelial activation of heparin cofactor II through biglycan. ApoE and Bgn double-deficient (ApoE−/−/Bgn−/0) mice showed higher activity of circulating thrombin, increased platelet activation and platelet adhesion in vivo, supporting a role of biglycan in balancing thrombin activity. Furthermore, concentrations of circulating cytokines and aortic macrophage content were elevated in ApoE−/−/Bgn−/0 mice, suggesting a proinflammatory phenotype. Elevated platelet activation and macrophage accumulation were reversed by treating ApoE−/−/Bgn−/0 mice with the thrombin inhibitor argatroban. Ultimately, ApoE−/−/Bgn−/0 mice developed aggravated atherosclerosis. Conclusions—The present results indicate that biglycan plays a previously unappreciated protective role during the progression of atherosclerosis by inhibiting thrombin activity, platelet activation, and finally macrophage-mediated plaque inflammation.

Loss of Somatostatin Receptor Subtype 2 in Prostate Cancer Is Linked to an Aggressive Cancer Phenotype, High Tumor Cell Proliferation and Predicts Early Metastatic and Biochemical Relapse

Somatostatin receptor subtype 2 (SSTR2) is the most frequently expressed SSTR subtype in normal human tissues. SSTR2 expression is differentially regulated in various tumor types and therapeutic somatostatin analogs binding to SSTR2 are in clinical use. In prostate cancers highly contradictory results in terms of SSTR2 expression and its consequences have been published over the past years. The aim of this study was to clarify prevalence and clinical significance of SSTR2 expression in prostate cancer. Therefore, quantitative immunohistochemistry (IHC) using a tissue microarray containing samples from 3,261 prostate cancer patients with extensive clinical and molecular cancer characteristics and oncological follow-up data was performed. IHC data was compared to publicly available Gene Expression Omnibus datasets of human prostate cancer gene expression arrays. While membranous SSTR2 staining was always seen in normal prostate epithelium, SSTR2 staining was absent in more than half (56.1%) of 2,195 interpretable prostate cancer samples. About 13% of all analyzed prostate cancers showed moderate to strong cytoplasmic and membranous SSTR2 staining. Staining intensities were inversely correlated with high Gleason grade, advanced pT category, high tumor cell proliferation (p<0.0001 each), high pre-operative PSA levels, (p = 0.0011) and positive surgical margins (p = 0.006). In silico analysis confirmed lower SSTR2 gene expression in prostate cancers vs. normal adjacent tissue (p = 0.0424), prostate cancer metastases vs. primary cancers (p = 0.0011) and recurrent vs. non-recurrent prostate cancers (p = 0.0438). PSA-free survival gradually declined with SSTR2 staining intensity (p<0.0001). SSTR2-negative cancers were more likely to develop metastases over time (p<0.05). In conclusion, most prostate cancers are indeed SSTR2-negative and loss of SSTR2 strongly predicts an unfavorable tumor phenotype and poor prognosis. Therefore, SSTR2 expression seems an important factor in the pathogenesis of prostate cancer and re-introduction of the receptor in SSTR2-negative prostate cancers may feature a promising target for novel gene therapy approaches.

Deletion of Hyaluronan Synthase 3 Inhibits Neointimal Hyperplasia

Objective— Hyaluronan (HA) is a polymeric glucosaminoglycan that forms a provisional extracellular matrix in diseased vessels. HA is synthesized by 3 different HA synthases (HAS1, HAS2, and HAS3). Aim of this study was to unravel the role of the HAS3 isoenzyme during experimental neointimal hyperplasia. Approach and Results— Neointimal hyperplasia was induced in Has3-deficient mice by ligation of the carotid artery. HA in the media of Has3-deficient mice was decreased 28 days after ligation, and neointimal hyperplasia was strongly inhibited. However, medial and luminal areas were unaffected. Cell density, proliferation, and apoptosis were not altered, suggesting a proportional decrease of both, the number of cells and extracellular matrix. In addition, endothelial function as determined by acetylcholine-induced relaxation of aortic rings, immunoblotting of endothelial nitric oxide synthase, and arterial blood pressure were not affected. Furthermore, the oxidative stress response was not affected as determined in total protein extracts from aortae. Transcriptome analysis comparing control versus ligated carotid arteries hinted toward a mitigated differential regulation of various signaling pathways in Has3-deficient mice in response to ligation that were related to vascular smooth muscle cell (VSMC) migration, including focal adhesions, integrins, mitogen-activated protein kinase, and phosphatidylinositol signaling system. Lentiviral overexpression of HAS3 in VSMC supported the migratory phenotype of VSMC in response to platelet-derived growth factor BB in vitro. Accordingly, knockdown of HAS3 reduced the migratory response to platelet-derived growth factor BB and in addition decreased the expression of PDGF-B mRNA. Conclusions— HAS3-mediated HA synthesis after vessel injury supports seminal signaling pathways in activation of VSMC, increases platelet-derived growth factor BB–mediated migration, and in turn enhances neointimal hyperplasia in vivo.

Lipidomes of lung cancer and tumour-free lung tissues reveal distinct molecular signatures for cancer differentiation, age, inflammation, and pulmonary emphysema

Little is known about the human lung lipidome, its variability in different physiological states, its alterations during carcinogenesis and the development of pulmonary emphysema. We investigated how health status might be mirrored in the lung lipidome. Tissues were sampled for both lipidomic and histological analysis. Using a screening approach, we characterised lipidomes of lung cancer tissues and corresponding tumour-free alveolar tissues. We quantified 311 lipids from 11 classes in 43 tissue samples from 26 patients. Tumour tissues exhibited elevated levels of triacylglycerols and cholesteryl esters, as well as a significantly lower abundance of phosphatidylglycerols, which are typical lung surfactant components. Adenocarcinomas and squamous cell carcinomas were distinguished with high specificity based on lipid panels. Lipidomes of tumour biopsy samples showed clear changes depending on their histology and, in particular, their proportion of active tumour cells and stroma. Partial least squares regression showed correlations between lipid profiles of tumour-free alveolar tissues and the degree of emphysema, inflammation status, and the age of patients. Unsaturated long-chain phosphatidylserines and phosphatidylinositols showed a positive correlation with a worsened emphysema status and ageing. This work provides a resource for the human lung lipidome and a systematic data analysis strategy to link clinical characteristics and histology.

Chronic UVB-irradiation actuates perpetuated dermal matrix remodeling in female mice: Protective role of estrogen

Chronic UVB-exposure and declined estradiol production after menopause represent important factors leading to extrinsic and intrinsic aging, respectively. Remodeling of the extracellular matrix (ECM) plays a crucial role in both responses. Whether the dermal ECM is able to recover after cessation of UVB-irradiation in dependence of estradiol is not known, however of relevance when regarding possible treatment options. Therefore, the endogenous sex hormone production was depleted by ovariectomy in female mice. Half of the mice received estradiol substitution. Mice were UVB-irradiated for 20 weeks and afterwards kept for 10 weeks without irradiation. The collagen-, hyaluronan- and proteoglycan- (versican, biglycan, lumican) matrix, collagen cleavage products and functional skin parameters were analyzed. The intrinsic aging process was characterized by increased collagen fragmentation and accumulation of biglycan. Chronic UVB-irradiation additionally augmented the lumican, versican and hyaluronan content of the dermis. In the absence of further UVB-irradiation the degradation of collagen and accumulation of biglycan in the extrinsically aged group was perpetuated in an excessive matter. Whereas estradiol increased the proteoglycan content, it reversed the effects of the perpetuated extrinsic response on collagen degradation. Suspension of the intrinsic pathway might therefore be sufficient to antagonize UVB-evoked long-term damage to the dermal ECM.