Nanomaterial-microbe cross-talk: physicochemical principles and (patho)biological consequences.

The applications of nanoparticles (NPs) are increasing exponentially in consumer products, biotechnology and biomedicine, and humans, as well as the environment, are increasingly being exposed to NPs. Analogously, various (pathogenic) microorganisms are present at all the major exposure and entry sites for NPs in the human body as well as in environmental habitats. However, the field has just started to explore the complex interplay between NPs and microbes and the (patho)biological consequences. Based on recent insights, herein, we critically reviewed the available knowledge about the interaction of NPs with microbes and the analytical investigations including the latest intravital imaging tools. We have commented on how the NPs' characteristics influence complex formation with microorganisms, presented the underlying physicochemical forces, and provided examples of how this knowledge can be used to rationally control the NP-microbe interaction. We concluded by discussing the role of the biomolecule corona in NP-microbe crosstalk and speculated the impact of NP-microbe complex formation on the (patho)biological outcome and fate of microbial pathogens. The presented insights will not only support the field in engineering NPs with improved anti-microbial activity but also stimulate research on the biomedical and toxicological relevance of nanomaterial-microbiome complex formation for the anthropocene in general.

[Histamine receptors in chronic inflammatory diseases of the nose and paranasal sinuses]. / Histaminrezeptoren bei chronisch-entzündlichen Erkrankungen der Nase und Nasennebenhöhlen.

BACKGROUND: Release of histamine from mast cells and basophils in inflammatory diseases of the nose and paranasal sinuses has been demonstrated in allergic and non-allergic processes. METHODS: A selective literature search was conducted in PubMed and Medline, and publications in German-language journals were additionally analyzed. RESULTS: The histamine receptors H1-H4 play a role in otorhinolaryngologic inflammatory diseases. To date, the histamine receptor subtype 4 (H4R), which is functionally expressed by immune cells in chronic inflammatory diseases, has received little attention. Stimulation of H4R influences the release of cytokines and chemokines as well as the migration behavior of immune cells. In animal models blockade of H4R reduced inflammation symptoms and pruritus. CONCLUSIONS: H4R plays a key role in the pathogenesis of chronic inflammatory diseases and may represent an interesting future therapeutic target.

[T-cell immune responses in chronic inflammatory diseases of the nasal mucosa]. / T-Zell-Immunreaktionen bei chronisch entzündlichen Erkrankungen der nasalen Schleimhäute.

Acute rhinosinusitis and chronic rhinosinusitis are inflammatory diseases of the mucosal membranes due to mislead immunological reactions to aeroallergens. T­cells are divided into different groups based on their cytokine secretion: T­helper type 1 (Th1) and type 2 (Th2) cells. The allergic immune response is caused by activation of specific Th2 cells. With specific immunotherapy, the mislead hyperactivated "allergic" immune response is reduced to a reaction within the normal range. The inflammatory forms of chronic rhinosinusitis are called endotypes, and, in the future, could enable a targeted, pathomechanistic therapy. These endotype-based treatment approaches target specific signaling pathways that have already shown good effects for chronic rhinosinusitis with nasal polyps using monoclonal antibodies. However, so far, only selected patients with non-rhinologic indications, off-label treatments, or in clinical trials have benefited from these treatments.

[Staging of oropharyngeal carcinomas : New TNM classification as a challenge for head and neck cancer centers]. / Staging von Oropharynxkarzinomen : Neue TNM-Klassifikation als Herausforderung für Kopf-Hals-Tumorzentren.

BACKGROUND: The TNM (tumor, nodes, metastasis) classification is updated periodically according to the literature and international recommendations. With the 8th edition, notable changes have been developed especially with regard to oropharyngeal cancer. MATERIALS AND METHODS: The modifications as well as the practicability of the classification for staging of oropharyngeal cancers are demonstrated on the basis of cases from the tumor database. RESULTS: The latest edition of the TNM classification realizes requirements to differentiate between human papilloma virus (HPV) positive and HPV-negative tumors during staging. Furthermore, the prognostic relevance of extranodal extension of lymph node metastases was integrated into the classification. While downstaging is performed regarding N category and Union Internationale Contre le Cancer (UICC) stage in many p16-positive tumors, for p16-negative tumors, extranodal spread mostly leads to a notable upstaging. Due to limited specificity of the p16 immunostaining, the relevance of false positive results has to be underlined. Missing integration of smoking behavior, limited standardization of the extranodal extension examination technique, as well as high demands on the documentation quality should be kept in mind. CONCLUSION: Clinical trials will have to show whether deescalation strategies regarding p16-positive carcinomas are supported by the changes made in the TNM staging system. A prospective multicenter study should examine the universal applicability, the appropriateness for all sublocations, as well as the prognostic significance of the current edition.

The nanoparticle biomolecule corona: lessons learned - challenge accepted?

Besides the wide use of engineered nanomaterials (NMs) in technical products, their applications are not only increasing in biotechnology and biomedicine, but also in the environmental field. While the physico-chemical properties and behaviour of NMs can be characterized accurately under idealized conditions, this is no longer the case in complex physiological or natural environments. Herein, proteins and other biomolecules rapidly bind to NMs, forming a protein/biomolecule corona that critically affects the NMs' (patho)biological and technical identities. As the corona impacts the in vitro and/or in vivo NM applications in humans and ecosystems, a mechanistic understanding of its relevance and of the biophysical forces regulating corona formation is mandatory. Based on recent insights, we here critically review and present an updated concept of corona formation and evolution. We comment on how corona signatures may be linked to effects at the nano-bio interface in physiological and environmental systems. In order to comprehensively analyse corona profiles and to mechanistically understand the coronas' biological/ecological impact, we present a tiered multidisciplinary approach. To stimulate progress in this field, we introduce the potential impact of the corona for NM-microbiome-(human)host interactions and the novel concept of 'nanologicals', i.e., the nanomaterial-specific targeting of molecular machines. We conclude by discussing the relevant challenges that still need to be resolved in this field.

Physicochemical characterization of nanoparticles and their behavior in the biological environment.

Whilst the physical and chemical properties of nanoparticles in the gas or idealized solvent phase can nowadays be characterized with sufficient accuracy, this is no longer the case for particles in the presence of a complex biological environment. Interactions between nanoparticles and biomolecules are highly complex on a molecular scale. The detailed characterization of nanoparticles under these conditions and the mechanistic knowledge of their molecular interactions with the biological world is, however, needed for any solid conclusions with regards to the relationship between the biological behavior of such particles and their physicochemical properties. In the present article we discuss some of the challenges with characterization and behavior of nanoparticles that are associated with their presence in chemically complex biological environments. Our focus is on the stability of colloids as well as on the formation and characteristics of protein coronae that have recently been shown to significantly modify the properties of pristine particles. Finally, we discuss the perspectives that may be expected from an improved understanding of nanoparticles in biological media.

The VEGF/VEGF-R axis in sporadic vestibular schwannomas correlates with irradiation and disease recurrence.

BACKGROUND/AIMS: The molecular mechanisms downstream of mutated neurofibromatosis type 2 (NF2) gene resulting in the growth and development of vestibular schwannoma (VS) are controversial. Several lines of evidence suggest the involvement of the vascular endothelial growth factor (VEGF) pathway in VS development. Given that recent studies of VEGF blockade in patients with NF2-associated VS showed positive effects on VS growth control, we initiated this comprehensive study of the VEGF pathway in sporadic VS. METHODS: A tissue microarray analysis of 182 sporadic VS was conducted. The expression of VEGF and its receptors as well as the proliferative activity of the tumors were quantified. The expression data were correlated to tumor volumes and diameters as well as to tumor recurrence and previous irradiation. RESULTS: All studied tumors expressed VEGF and its receptors. Proliferative activity was related to the growth characteristics of the tumors. Moreover, we found significantly higher VEGF levels in recurrent tumors (p = 0.0387) and in preoperatively irradiated tumors (p = 0.0213). CONCLUSION: Our data suggest a relevant role of the VEGF pathway in VS growth and therapy outcome. Therefore, targeting this pathway using antiangiogenic compounds might be beneficial for patients with sporadic VS, especially those with recurrent or irradiated tumors.

[Interferon α therapy in patients with chronic hepatitis C infection: biopsychosocial consequences]. / Interferon α bei Patienten mit chronischer Hepatitis C : Biopsychosoziale Auswirkungen.

BACKGROUND: Interferon α (IFN-alpha) is widely used in the treatment of viral infections, including hepatitis C. Unfortunately depression is a common side effect of IFN-alpha therapy. The presence of depressive symptoms is important because they have an adverse effect on the course of the illness and reduce the quality of life and the treatment adherence. The current prospective study examines the effects of IFN-alpha on the development of depressive disorders, on cognitive functioning and on quality of life. METHOD: A total of 25 patients with chronic hepatitis C infection were investigated. All patients were treated in the Department of Gastroenterology and Hepatology, University of Medicine of Graz, Austria. Psychometric observer rating and self-rating scales were administered 1 month and 3 months after the beginning of the antiviral treatment to evaluate depressive symptoms [Beck Depression Inventory (BDI); Hamilton Depression Scale]. The data on life satisfaction before therapy and health-related quality of life were obtained from the Fragebogen zur Lebenszufriedenheit (FLZ) and the SF-36 (Health Status Questionnaire). Cognitive function was based on the SKT (Syndrom Kurztest). All patients completed the Social Support Questionnaire (SSS), a multidimensional self-report measure of social support. RESULTS: Three months after the initial IFN-alpha administration in the whole sample significant impairments in health-related quality of life were found in the health-related domains "physical functioning", "role physical", "role emotional", "social functioning" and "vitality". The whole sample showed cognitive impairments. No changes in social support were recorded. Three months after the first INF-alpha administration, 48% (n=12) of the sample suffered from moderate clinical depression. In comparison to patients without pathological affective findings, patients with INF-alpha-induced clinical depression showed decreased life satisfaction before the initial antiviral therapy. Impairments in health-related quality of life (SF-36) were found in the sample with clinical depression in the health-related domains "general health", "social functioning", "role emotional", "vitality" and "mental health". CONCLUSION: Hepatitis C is associated with an increased prevalence of psychiatric disorders, particularly depression. INF-alpha patients having low levels of life satisfaction in the domains "self-concept" (skills, appearance, self-confidence, vitality …), "employment" and "physical health and constitution" seem to face a major risk of depression.

[Possible molecular mechanisms of spontaneous remission in sudden idiopathic hearing loss]. / Mögliche molekulare Mechanismen einer Spontanremission nach Hörsturz.

According to current knowledge, it must be assumed that temporary idiopathic hearing loss and its spontaneous remission are based on mechanical and/or pathological alterations in the inner ear. The causal mechanisms might be based on inter-individual variations. Induced by dose-dependent activators, temporary as well as permanent damage might occur. Sudden hearing loss may be initiated by an increase in the local nitric oxide (NO) concentration. Spontaneous remission, i.e. functional restoration, can be explained by a local decrease in the NO concentration. In this context, regulatory systems such as the gap-junction system, blood vessels or synapses might be affected. In addition, alterations in the hormone level of estrogen and mineralocorticoids, as well as cellular glutathione and vitamin levels, might lead to temporary alterations in the inner ear. Recent experimental findings indicate a role for the shuttle protein Survivin in the spontaneous remission of sudden hearing loss.

The HIV-1 virion-associated protein vpr is a coactivator of the human glucocorticoid receptor.

The HIV-1 virion-associated accessory protein Vpr affects both viral replication and cellular transcription, proliferation, and differentiation. We report that Vpr enhances the activity of glucocorticoids in lymphoid and muscle-derived cell lines by interacting directly with the glucocorticoid receptor and general transcription factors, acting as a coactivator. Vpr contains the signature motif LXXLL also present in cellular nuclear receptor coactivators, such as steroid receptor coactivator 1 and p300/CREB-binding protein, which mediates their interaction with the glucocorticoid and other nuclear hormone receptors. A mutant Vpr molecule with disruption of this coactivator signature motif lost its ability to influence transcription of glucocorticoid-responsive genes and became a dominant-negative inhibitor of Vpr, possibly by retaining its general transcription factor-binding activities. The glucocorticoid coactivator activity of Vpr may contribute to increased tissue glucocorticoid sensitivity in the absence of hypercortisolism and to the pathogenesis of AIDS.

Cofactor requirements for nuclear export of Rev response element (RRE)- and constitutive transport element (CTE)-containing retroviral RNAs. An unexpected role for actin.

Nuclear export of proteins containing leucine-rich nuclear export signals (NESs) is mediated by the export receptor CRM1/exportin1. However, additional protein factors interacting with leucine-rich NESs have been described. Here, we investigate human immunodeficiency virus type 1 (HIV-1) Rev-mediated nuclear export and Mason-Pfizer monkey virus (MPMV) constitutive transport element (CTE)-mediated nuclear export in microinjected Xenopus laevis oocytes. We show that eukaryotic initiation factor 5A (eIF-5A) is essential for Rev and Rev-mediated viral RNA export, but not for nuclear export of CTE RNA. In vitro binding studies demonstrate that eIF-5A is required for efficient interaction of Rev-NES with CRM1/exportin1 and that eIF-5A interacts with the nucleoporins CAN/nup214, nup153, nup98, and nup62. Quite unexpectedly, nuclear actin was also identified as an eIF-5A binding protein. We show that actin is associated with the nucleoplasmic filaments of nuclear pore complexes and is critically involved in export processes. Finally, actin- and energy-dependent nuclear export of HIV-1 Rev is reconstituted by using a novel in vitro egg extract system. In summary, our data provide evidence that actin plays an important functional role in nuclear export not only of retroviral RNAs but also of host proteins such as protein kinase inhibitor (PKI).

[The relationship between emotional distress, cognitive performance and health - related quality of life in patients with hepatitis C prior to antiviral treatment]. / Der Zusammenhang zwischen emotionalen Befindlichkeitsstörungen, kognitiver Leistungsfähigkeit und gesundheitsbezogener Lebensqualität bei mit dem Hepatitis-C-Virus infizierten Patienten vor einer antiviralen Therapie.

Recent epidemiologic studies suggest that more than 175 million individuals are infected with hepatitis C virus (HCV) worldwide. In the past few years, outcome studies in chronic HCV patients are no longer focusing solely on traditional end points such as mortality rates but on psychosocial well-being such as health-related quality of life (HRQoL), emotional states, and neuropsychological functioning. The purpose of our exploratory study was to assess cross sectionally the frequency of depression, posttraumatic stress symptoms, cognitive deficits, and impairments in HRQoL in chronic HCV patients prior to antiviral treatment, and to investigate how cognitive impairments and emotional distress were related to quality of life. We recruited 34 chronic HCV patients who had presented for initial assessment of the need for antiviral therapy. Psychometric observer-rating and self-rating scales were administered to evaluate posttraumatic stress symptoms (PTSS-10), depressive symptoms (BDI), HRQoL (SF-36 Health Status Questionnaire), and cognitive functioning (SKT). 32.4 % (n = 11) of the sample suffered from clinical depression, and 8.8 % (n = 3) had a posttraumatic stress syndrome. 8.8 % (n = 3) of the sample showed cognitive impairments. Significant impairments in HRQoL were found in the health-related domains vitality, role-emotional, and role-physical. The severity of emotional distress as measured on the BDI and PTSS-10 was associated with decrements in HRQoL. However, lower cognitive function scores on the SKT were not associated with lower HRQoL SF-36 values. Chronic HCV patients seem to face a major risk of depression, posttraumatic stress symptoms, and cognitive dysfunction, and the presence of emotional distress is associated with impairments in quality of life. We therefore underscore the need for early and comprehensive bio-psycho-social diagnosis and therapy of chronic HCV patients in order to treat emotional distress and enhance patients; quality of life at an early stage before initiating antiviral therapy, as well as to expand the pool of patients eligible to receive antiviral therapy.

Sensitivity and specificity of bispectral index for classification of overt hepatic encephalopathy: a multicentre, observer blinded, validation study.

BACKGROUND: The severity of hepatic encephalopathy is currently graded clinically using West Haven criteria and psychometric tests. OBJECTIVE: To assess the discriminative power of the bispectral index (BIS) monitor to classify the degree and progression of hepatic encephalopathy. DESIGN: A consecutive, multicentre, observer blinded validation study. SETTING: Medical University of Graz (Graz, Austria), Zhejiang University First Affiliated Hospital (Hang Zhou, China), and Cairo University (Cairo, Egypt). PATIENTS: 28 consecutive patients with hepatic encephalopathy were first enrolled at Medical University of Graz as a test set. The estimated BIS cut off values were subsequently tested in a validation set of 31 patients at Zhejiang University First Affiliated Hospital and 26 patients at Cairo University; 18 patients were reassessed later in a longitudinal study. Fifteen of 85 patients (18%) were excluded from the final analysis (11 became too agitated with high electromyographic activity; four fell asleep during the recording). RESULTS: Applying the Austrian BIS cut off values of 85, 70, and 55 for discriminating West Haven grades 1 to 4 yielded agreement between BIS classification and West Haven grades in 40 of the 46 validation patients (87%), and in 16 of the 18 follow up patients (89%). Mean (SD) BIS values differed significantly between patients with West Haven grade 1 (90.2 (2.5)), grade 2 (78.4 (6.6)), grade 3 (63.2 (4.8)), and grade 4 (45.4 (5.0)). CONCLUSIONS: BIS is a useful measure for grading and monitoring the degree of involvement of the central nervous system in patients with chronic liver disease.

Albumin infusion fails to restore circulatory function following paracentesis of tense ascites as assessed by beat-to-beat haemodynamic measurements.

AIMS: To study whether circulatory changes during large volume paracentesis (LVP) in patients with liver cirrhosis and tense ascites as assessed by novel non-invasive haemodynamic measuring technology are reversed by subsequent albumin infusion. MATERIALS AND METHODS: Eleven patients with portal hypertensive ascites secondary to liver cirrhosis of Child's class B or C were studied during LVP (10.7 +/- 4.4 l) and subsequent infusion of albumin. Digital arterial pulse waves were continuously measured by vascular unloading technique providing data for beat-to-beat values of systolic (P(s)), diastolic (P(d)) and mean arterial pressures (P(m)), respectively, as well as for heart rate (F(h)), stroke volume (V(s)), cardiac output (Q(co)) and peripheral resistance (R). Data extrapolated to the end of paracentesis, albumin infusion and follow-up phases were compared with the end of the equilibration phase. RESULTS: At the end of paracentesis, P(s), P(m) and P(d) changed by -14 +/- 15% (p < 0.05), -16 +/- 11% (p < 0.01) and -17 +/- 11% (p < 0.001), respectively, whereas Q(co) and F(h) did not change substantially. There was a highly significant increase in V(s) by +21 +/- 25% (p < 0.01). The largest change was seen in R which significantly decreased by -29 +/- 24% (p < 0.01). This change was not reversed by infusion of albumin and persisted up to the end of follow-up. CONCLUSION: The haemodynamic changes following LVP appear to be first and foremost controlled by changes in peripheral resistance with insufficient cardiac compensation. Further studies combining albumin with vasopressors for prevention of paracentesis-induced circulatory changes are needed.

Soluble CD163 and soluble mannose receptor predict survival and decompensation in patients with liver cirrhosis, and correlate with gut permeability and bacterial translocation.

BACKGROUND: Activated hepatic macrophages play a key role in inflammation and fibrosis progression in chronic liver disease. AIM: To assess the prognostic value of soluble (s)CD163 and mannose receptor (sMR) in cirrhotic patients and explore associations with markers of intestinal permeability (lactulose-mannitol ratio, diamine oxidase), bacterial translocation (endotoxin, lipopolysaccharide-binding protein) and markers of systemic immune activation (interleukin-6, interleukin-8, sCD14). METHODS: We prospectively investigated 101 cirrhotic patients (Child-Pugh class A: n = 72, Child-Pugh classes B and C: n = 29) and 31 healthy controls. Patients were observed for a median follow-up of 37 months. RESULTS: Median plasma levels of sCD163 and soluble mannose receptor were significantly elevated in cirrhotic patients (P < .001) and increased with disease severity (sCD163 in healthy controls = 1.3, Child-Pugh class A = 4.2, Child-Pugh classes B and C = 8.4 mg/L; sMR in healthy controls = 15.8, Child-Pugh class A = 36.5, Child-Pugh classes B and C = 66.3 µg/dL). A total of 21 patients died during the observation period. Patients with sCD163 levels above 5.9 mg/L showed significantly reduced survival (survival rate after 36 months: 71% versus 98%, P < .001). Patients with soluble mannose receptor levels above 45.5 µg/dL developed significantly more complications of cirrhosis within 12 months (73% versus 9%, P < .001). Furthermore, both variables correlated with the lactulose-mannitol ratio, diamine oxidase, lipopolysaccharide and interleukin-8. CONCLUSION: Our data demonstrate the prognostic value of sCD163 in predicting long-term survival in patients with liver cirrhosis and identify soluble mannose receptor as a prognostic marker for occurrence of cirrhosis-associated complications. The correlation between gut barrier dysfunction and activation of macrophages points towards a link between them.

Physiological and pathological changes in the redox state of human serum albumin critically influence its binding properties.

Binding and transport of a number of endogenous and exogenous compounds is an important function of the main plasma protein, albumin. In vivo and in vitro, albumin may be oxidatively modified in different ways with different agents at different sites. These modifications have various consequences on the physiological functions of albumin. Diabetes mellitus, liver diseases and nephropathy are just a few examples of disorders in which oxidative stress is involved and altered albumin functions have been described. This review is focussed on the consequences of oxidative modification on the binding properties of albumin. These range from no effect to decreased or increased binding affinities depending on the ligand under investigation and the type of modification. Indicators for modification include glycosylation, disulphide formation or the content of carbonyl groups. The redox state of albumin can affect the binding properties in several ways, including altered conformation and consequently altered affinities at binding sites and altered binding when the binding reaction itself is redox sensitive. The physiological or pathophysiological concentrations of different oxidatively modified albumin molecules vary over a wide range and are crucial in assessing the clinical relevance of altered ligand binding properties of a particularly modified albumin species in various disease conditions.

Transcription-dependent nuclear-cytoplasmic trafficking is required for the function of the von Hippel-Lindau tumor suppressor protein.

Mutation of the von Hippel-Lindau tumor suppressor gene (vhl) causes the von Hippel-Lindau cancer syndrome as well as sporadic renal clear cell carcinoma. To pursue our study of the intracellular localization of VHL protein in relation to its function, we fused VHL to the green fluorescent protein (GFP) to produce the VHL-GFP fusion protein. Like VHL, VHL-GFP binds to elongins B and C and Cullin-2 and regulates target gene product levels, including levels of vascular endothelial growth factor and glucose transporter 1. VHL-GFP localizes predominantly to the cytoplasm, with some detectable nuclear signal. Inhibition of transcription by actinomycin D or 5,6-dichlorobenzimidazole riboside (DRB) causes VHL to be redistributed to the nucleus. A cellular fusion assay was used to demonstrate that inhibition of transcription induces a decrease in the nuclear export rate of VHL. The dependence of transcription for trafficking is lost with a deletion of exon 2, a region with a mutation causing a splice defect in the VHL gene in sporadic renal clear cell carcinoma. Addition of a strong nuclear export signal (NES) derived from the Rev protein results in complete nuclear exclusion and abrogates the redistribution of VHL-GFP-NES into the nucleus upon inhibition of transcription. Leptomycin B, which inhibits NES-mediated nuclear export, reverts the distribution of VHL-GFP-NES to that of VHL-GFP and restores sensitivity to actinomycin D and DRB. Uncoupling of VHL-GFP trafficking to transcription either by an exon 2 deletion or fusion to NES abolishes VHL function. We suggest that VHL function requires not only nuclear or cytoplasmic localization, but also exon 2-mediated transcription-dependent trafficking between these two cellular compartments.

HDAC1 and HDAC2 integrate the expression of p53 mutants in pancreatic cancer.

Mutation of p53 is a frequent genetic lesion in pancreatic cancer being an unmet clinical challenge. Mutants of p53 have lost the tumour-suppressive functions of wild type p53. In addition, p53 mutants exert tumour-promoting functions, qualifying them as important therapeutic targets. Here, we show that the class I histone deacetylases HDAC1 and HDAC2 contribute to maintain the expression of p53 mutants in human and genetically defined murine pancreatic cancer cells. Our data reveal that the inhibition of these HDACs with small molecule HDAC inhibitors (HDACi), as well as the specific genetic elimination of HDAC1 and HDAC2, reduce the expression of mutant p53 mRNA and protein levels. We further show that HDAC1, HDAC2 and MYC directly bind to the TP53 gene and that MYC recruitment drops upon HDAC inhibitor treatment. Therefore, our results illustrate a previously unrecognized class I HDAC-dependent control of the TP53 gene and provide evidence for a contribution of MYC. A combined approach targeting HDAC1/HDAC2 and MYC may present a novel and molecularly defined strategy to target mutant p53 in pancreatic cancer.

Taspase1: a 'misunderstood' protease with translational cancer relevance.

Proteolysis is not only a critical requirement for life, but the executing enzymes also play important roles in numerous pathological conditions, including cancer. Therefore, targeting proteases is clearly relevant for improving cancer patient care. However, to effectively control proteases, a profound knowledge of their mechanistic function as well as their regulation and downstream signalling in health and disease is required. The highly conserved protease Threonine Aspartase1 (Taspase1) is overexpressed in numerous liquid and solid malignancies and was characterized as a 'non-oncogene addiction' protease. Although Taspase1 was shown to cleave various regulatory proteins in humans as well as leukaemia provoking mixed lineage leukaemia fusions, our knowledge on its detailed functions and the underlying mechanisms contributing to cancer is still incomplete. Despite superficial similarity to type 2 asparaginases as well as Ntn proteases, such as the proteasome, Taspase1-related research so far gives us the picture of a unique protease exhibiting special features. Moreover, neither effective genetic nor chemical inhibitors for this enzyme are available so far, thus hampering not only to further dissect Taspase1's pathobiological functions but also precluding the assessment of its clinical impact. Based on recent insights, we here critically review the current knowledge of Taspase1's structure-function relationship and its mechanistic relevance for tumorigenesis obtained from in vitro and in vivo cancer models. We provide a comprehensive overview of tumour entities for which Taspase1 might be of predictive and therapeutic value, and present the respective experimental evidence. To stimulate progress in the field, a comprehensive overview of Taspase1 targeting approaches is presented, including coverage of Taspase1-related patents. We conclude by discussing future inhibition strategies and relevant challenges, which need to be resolved by the field.