A Feasibility Study Investigating an Exercise Program in Metastatic Cancer Based on the Patient-Preferred Delivery Mode

BACKGROUND

Feasibility of exercise in patients with metastatic cancer is still a challenge. This study aimed to determine the feasibility and preliminary efficacy of an exercise intervention based on a patient-preferred delivery mode in patients affected by metastatic cancer.

MATERIALS AND METHODS

Forty-four patients with a confirmed diagnosis of metastatic cancer were recruited in a 3-month exercise program. Whereas the exercise program consisted of aerobic and resistance activities performed twice a week, the participants may choose the mode of delivery: home based, personal training, or group based. The primary endpoint was the feasibility, defined by recruitment rate, attendance, adherence, dropout rate, tolerability (comparing the session RPE with the target RPE), and safety (using the Common Terminology Criteria for Adverse Events, version 5.0). Secondary endpoints included cardiorespiratory fitness (six minutes walking test), muscle strength (handgrip strength test and isometric leg press test), flexibility (the back scratch and chair sit and reach tests), anthropometric parameters (body mass index and waist-hip ratio), quality of life (EORTC QLQ C-30 questionnaire), and amount of physical exercise (Godin's Shepard Leisure Time Exercise Questionnaire). Descriptive statistics, Student t test, and Wilcoxon signed rank test were used to analyze data.

RESULTS

The study recruitment rate was 81%. Out of 44 recruited patients, 28 chose the personal training program, 16 chose the home-based program, and none chose the group-based program. Nine dropouts occurred (20%), 6 in the personal training program, and 3 in the home-based intervention. The median attendance rate was 92%, adherence was 88%, tolerability was 100%, and 9 nonsevere adverse events were registered during the exercise sessions. An increase in cardiorespiratory fitness (P < .001) and flexibility (P = .011 for chair sit and reach; P = .040 for back scratch) was observed at the end of the intervention, while no changes in anthropometric values and muscle strength were detected. Different quality-of-life domains were improved following the intervention, including physical (P = .002), emotional (P < .001), and role functioning (P = .018), fatigue (P = .030), and appetite loss (P = .005).

CONCLUSION

A 3-month exercise program based on a patient-preferred delivery mode is feasible in patients with metastatic cancer and may improve physical function and quality of life.

TRIAL REGISTRATION

NCT04226508.

From asking to observing. Behavioural measures of socio-emotional and motivational skills in large-scale assessments

Socio-emotional and motivational skills are routinely measured using self-reports in large-scale educational assessments. Measures exploiting test-takers' behaviour during the completion of questionnaires or cognitive tests are increasingly used as alternatives to self-reports in the economics of education literature. We compute behavioural measures of socio-emotional and motivational skills using data from the Programme for International Student Assessment (PISA). We find that these measures capture important aspects of students' academic profiles: some are importantly associated with contemporaneous performance and educational attainment and most measures have a high degree of stability over time. However, these measures are only limitedly correlated among themselves and have low correlations with self-report measures of the same constructs. This is likely a reflection of the fact that behavioural measures are representations of the test taker current 'state', rather than descriptions of the participant view of their own 'trait' like the self-report measures. Moreover, the low correlation across measures suggests that they capture different behavioural responses to the test-taking situation. These differences are still limitedly understood because the measures are constructed ex-post using collateral information collected during the administration of assessments rather than developed ex ante in line with theoretical models of human cognition and affect.

Additional biological and clinical characteristics to refine International Metastatic RCC Database Consortium (IMDC) prognostic/predictive assessment in metastatic renal cell carcinoma (mRCC)

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Background: mRCC prognostic stratification is currently based on the IMDC score. However, some patients experience outcomes markedly different from those predicted by the median outcome of their risk class. Moreover, risk scores are prognostic, rather than predictive, and developing reproducible, affordable, biology-based predictive biomarkers to tailor treatment choices in individual pts remains an unmet clinical need. Methods: A retrospective cohort of 113 mRCC pts treated at the Verona University Hospital Trust between 2013 and 2021 was explored to identify additional clinical prognostic factors for OS to complement IMDC score. Outlier pts (i.e. individual pts whose clinical outcome differed significantly from the median of the IMDC group they belonged to) were further explored to find putative molecular signatures, using FISH and IHC assays. Results: At a median follow-up of 69 months (range 18-136m), novel variables impacting on OS in addition to IMDC risk group were identified: bone, central nervous system (CNS) and pancreatic mets and high neutrophil/lymphocyte ratio (N/L) with a cut-off of 3.2. We also analyzed outliers: 3 good-risk pts with lower than expected OS, 4 poor-risk pts with longer than expected OS, and two intermediate-risk pts with long treatment response. Two putative signatures were found predictive of disease behavior: a cold signature (9p loss, poor of TILs) and a hot signature (rich in CD56+, CD15+ and CD8+ infiltrating cells). The cold and hot signatures were found in good risk pts with bad OS and poor-risk pts good OS, respectively; both intermediate-risk pts had a hot signature, consistent with their disease course. Conclusions: Additional clinical and molecular factors have been identified to possibly improve IMDC prognostic performance; multivariable models including them along with standard IMDC are being developed. Molecular analysis suggests potential signatures to be applied in routine clinical practice, whose predictive performance could be validated in prospective multicentric trials. [Table: see text]

Melanoma secretion of transforming growth factor-β2 leads to loss of epidermal AMBRA1 threatening epidermal integrity and facilitating tumour ulceration

BACKGROUND

For patients with early American Joint Committee on Cancer (AJCC)-stage melanoma the combined loss of the autophagy regulatory protein AMBRA1 and the terminal differentiation marker loricrin in the peritumoral epidermis is associated with a significantly increased risk of metastasis.

OBJECTIVES

The aim of the present study was to evaluate the potential contribution of melanoma paracrine transforming growth factor (TGF)-β signalling to the loss of AMBRA1 in the epidermis overlying the primary tumour and disruption of epidermal integrity.

METHODS

Immunohistochemistry was used to analyse AMBRA1 and TGF-β2 in a cohort of 109 AJCC all-stage melanomas, and TGF-β2 and claudin-1 in a cohort of 30 or 42 AJCC stage I melanomas, respectively, with known AMBRA1 and loricrin (AMLo) expression. Evidence of pre-ulceration was analysed in a cohort of 42 melanomas, with TGF-β2 signalling evaluated in primary keratinocytes.

RESULTS

Increased tumoral TGF-β2 was significantly associated with loss of peritumoral AMBRA1 (P < 0·05), ulceration (P < 0·001), AMLo high-risk status (P < 0·05) and metastasis (P < 0·01). TGF-β2 treatment of keratinocytes resulted in downregulation of AMBRA1, loricrin and claudin-1, while knockdown of AMBRA1 was associated with decreased expression of claudin-1 and increased proliferation of keratinocytes (P < 0·05). Importantly, we show loss of AMBRA1 in the peritumoral epidermis was associated with decreased claudin-1 expression (P < 0·05), parakeratosis (P < 0·01) and cleft formation in the dermoepidermal junction (P < 0·05).

CONCLUSIONS

Collectively, these data suggest a paracrine mechanism whereby TGF-β2 causes loss of AMBRA1 overlying high-risk AJCC early-stage melanomas and reduced epidermal integrity, thereby facilitating erosion of the epidermis and tumour ulceration.

Performance decline in a low-stakes test at age 15 and educational attainment at age 25: Cross-country longitudinal evidence

INTRODUCTION

Educational attainment is associated with important life outcomes including labour market performance, health status, well-being, civic and political participation. An important question is whether it is possible to identify early those students who lack the achievement motivation that is needed to complete a higher education degree.

METHODS

Longitudinal follow-ups of representative samples of participants in the 2000 and 2003 Programme for International Student Assessment (PISA) from Australia, Denmark and Switzerland (N = 3110; 1130; and 1962; age = 15 to 27; % females 51%, 51%, 49%; ethnicity/race unknown) were used to identify the association between a measure of effort on a cognitively demanding low-stake task at age 15 - performance decline during the test - and educational attainment at age 25-27.

RESULTS

A one SD difference in performance decline was associated with a 5-6 percentage point difference in the probability of obtaining tertiary-level qualifications (r = -0.15 in Australia; -0.11 in Denmark and -0.11 in Switzerland). We find no evidence of differences in this relationship across genders, socio-economic status and baseline levels of ability in the three countries. The association between performance decline and educational attainment is homogeneous across these groups. Self-reported measures of achievement motivation were not predictive of educational attainment in the three countries.

CONCLUSIONS

Our work contributes new longitudinal evidence to the body of research in education employing behavioural measures of motivation and engagement. It can be used to understand the potential long-term consequences of disparities in students' preparation to sustain effort over cognitively demanding tasks.

Is subareolar intraoperative biopsy still necessary to predict nipple involvement?

OBJECTIVE

To predict the occult tumor involvement of nipple-areola complex (NAC) using preoperative MR imaging and to investigate whether the intraoperative histopathological examination of the subareolar tissue is still necessary.

PATIENTS AND METHODS

Out of 712 patients submitted to nipple-sparing mastectomy (NSM) between 2014 and 2019, we selected 188 patients who underwent preoperative breast MRI. Breast MRI and intraoperative histopathological examination of the subareolar tissue were performed to predict NAC involvement at permanent pathology. All parameters were correlated with final pathological NAC assessment by univariate and multivariate analysis.

RESULTS

Forty-three patients (22.9%) had tumor involvement of the NAC. At univariate analysis, non-mass enhancement type (p = 0.009), multifocality/multicentricity (p = 0.002), median tumor size (p < 0.001), median tumor-NAC distance measured by MRI (p < 0.001), tumor-NAC distance ≤ 10 mm (p < 0.001) and tumor-NAC distance ≤ 20 mm (p < 0.001), and lymphovascular invasion (p = 0.001) were significantly correlated with NAC involvement. At multivariate analysis, only tumor-NAC distance ≤ 10 mm retained statistical significance. The sensitivity and specificity of MRI tumor-NAC distance ≤ 10 mm were 79.1% and 97.2% and those of intraoperative pathologic assessment were 74,4% and 100%, respectively.

CONCLUSIONS

Tumor-NAC distance is the only reliable MRI characteristic that can predict NAC involvement in breast cancer patients. Although several cut-offs showed promising performances, intraoperative pathologic assessment is still mandatory.

Transglutaminase Type 2 is Involved in the Hematopoietic Stem Cells Homeostasis

Type 2 transglutaminase (TG2) is a multifunctional protein involved in various biological processes playing a key regulatory role in cell homeostasis such as cell death and autophagy. New evidence is emerging that support an important role of autophagy in regulating normal hematopoiesis. Prompted by these findings, in this study we investigated in vivo involvement of TG2 in mouse hematopoiesis under normal or nutrient deprivation conditions. We found that the number and rate of differentiation of bone marrow hematopoietic stem cell was decreased in the TG2 knockout mice. We present evidence showing that these effects on hematopoietic system are very likely due to the TG2-dependent impairment of autophagy. In fact, stimulation of autophagy by starvation is able to rescue the block of the differentiation of stem cells progenitors in the TG2 KO mice. It was also shown that the RhoA/ERK½ pathway, known to be essential for regulation of the bone marrow progenitor cells homeostasis, was significantly impaired in the absence of TG2. Hence, this study expanded our knowledge about TG2 discovering a role of this enzyme in regulation of hematopoiesis.

Multiparametric MR imaging of the prostate at 1.5-T without endorectal coil using an 8 channel pelvic phased array: Is it still a viable option?

INTRODUCTION

The purpose of our work was to evaluate the feasibility of prostate multiparametric MR imaging at 1.5-T without endorectal coil using an 8 channel pelvic phased array coil.

MATERIAL AND METHODS

A total of 154 patients who underwent mp-MRI were retrospectively included. Patients received a standardized mp-MRI, compliant with 2012 European Society of Uro-Radiology guidelines, with 1·5 T magnetic field strength and an 8 channel pelvic phased-array coil. Two blinded readers graded the image quality of mp-MRI on a three-point scale and they scored the prostate lesions according to PI-RADS v2. All PI-RADS of 4 or 5 underwent biopsy. A third radiologist and a pathologist verified the correspondence between the MRI images and the results of the biopsy.

RESULTS

64 (41.6%) patients showed a Pi-rads of 4 or 5. At biopsy, 79.7% showed a Gleason score ≥7, 12.5% showed a Gleason score of 6 and 7.8% showed a negative biopsy. In the group of Pi-rads ≤ 3, 12 patients underwent a biopsy with the following results: negative biopsy in 33.3%, atypical Small Acinar Proliferation in 16.7%, prostatic intraepithelial neoplasia in 25% and indolent PCa 25%. Mp-MRI in the identification of clinically significant cancer provided a low percentage of false positive (7.8%) while in 79.7% of cases it was capable to detect clinically significant prostate cancer. In 92.2% of patients mp-MRI identified a prostate cancer with a Gleason score ≥6. The inter-reader agreement was excellent in defining both the quality of the examination and the PI-RADS category (k = 0.83 and k = 0.70, respectively).

CONCLUSIONS

mp-MRI at 1.5-T without endorectal coil using an 8 channel phased array is an appropriate tool for early detection of clinically significant prostate cancer.

IMPLICATIONS FOR PRACTICE

8 channel pelvic phased array is still an appropriate tool for early detection of clinically significant prostate cancer and for obtaining a reduction in overdiagnosis of indolent PCa.

Autophagy induction in atrophic muscle cells requires ULK1 activation by TRIM32 through unanchored K63-linked polyubiquitin chains

Optimal autophagic activity is crucial to maintain muscle integrity, with either reduced or excessive levels leading to specific myopathies. LGMD2H is a muscle dystrophy caused by mutations in the ubiquitin ligase TRIM32, whose function in muscles remains not fully understood. Here, we show that TRIM32 is required for the induction of muscle autophagy in atrophic conditions using both in vitro and in vivo mouse models. Trim32 inhibition results in a defective autophagy response to muscle atrophy, associated with increased ROS and MuRF1 levels. The proautophagic function of TRIM32 relies on its ability to bind the autophagy proteins AMBRA1 and ULK1 and stimulate ULK1 activity via unanchored K63-linked polyubiquitin. LGMD2H-causative mutations impair TRIM32's ability to bind ULK1 and induce autophagy. Collectively, our study revealed a role for TRIM32 in the regulation of muscle autophagy in response to atrophic stimuli, uncovering a previously unidentified mechanism by which ubiquitin ligases activate autophagy regulators.

Transglutaminase type 2 plays a key role in the pathogenesis of Mycobacterium tuberculosis infection

BACKGROUND

Mycobacterium tuberculosis (MTB), the aetiological agent of tuberculosis (TB), is capable of interfering with the phagosome maturation pathway, by inhibiting phagosome-lysosome fusion and the autophagic process to ensure survival and replication in macrophages. Thus, it has been proposed that the modulation of autophagy may represent a therapeutic approach to reduce MTB viability by enhancing its clearance.

OBJECTIVE

The aim of this study was to investigate whether transglutaminase type 2 (TG2) is involved in the pathogenesis of MTB.

RESULTS

We have shown that either genetic or pharmacological inhibition of TG2 leads to a marked reduction in MTB replicative capacity. Infection of TG2 knockout mice demonstrated that TG2 is required for MTB intracellular survival in macrophages and host tissues. The same inhibitory effect can be reproduced in vitro using Z-DON, a specific inhibitor of the transamidating activity of TG2. Massive cell death observed in macrophages that properly express TG2 is hampered by the absence of the enzyme and can be largely reduced by the treatment of wild-type macrophages with the TG2 inhibitor. Our data suggest that reduced MTB replication in cells lacking TG2 is due to the impairment of LC3/autophagy homeostasis. Finally, we have shown that treatment of MTB-infected murine and human primary macrophages with cystamine, a TG2 inhibitor already tested in clinical studies, causes a reduction in intracellular colony-forming units in human macrophages similar to that achieved by the anti-TB drug capreomycin.

CONCLUSION

These results suggest that inhibition of TG2 activity is a potential novel approach for the treatment of TB.

Role of autophagy in HIV infection and pathogenesis

The aim of autophagy is to re-establish homeostasis in response to a variety of stress conditions. By forming double-membrane vesicles, autophagy engulfs damaged or superfluous cytoplasmic material and recycles degradation products for new synthesis or energy production. Of note, the same mechanism is used to capture pathogens and has important implications in both innate and adaptive immunity. To establish a chronic infection, pathogens have therefore evolved multiple mechanisms to evade autophagy-mediated degradation. HIV infection represents one of the best characterized systems in which autophagy is disarmed by a virus using multiple strategies to prevent the sequestration and degradation of its proteins and to establish a chronic infection. HIV alters autophagy at various stages of the process in both infected and bystander cells. In particular, the HIV proteins TAT, NEF and ENV are involved in this regulation by either blocking or stimulating autophagy through direct interaction with autophagy proteins and/or modulation of the mTOR pathway. Although the roles of autophagy during HIV infection are multiple and vary amongst the different cell types, several lines of evidence point to a potential beneficial effect of stimulating autophagy-mediated lysosomal degradation to potentiate the immune response to HIV. Characterization of the molecular mechanisms regulating selective autophagy is expected to be valuable for developing new drugs able to specifically enhance the anti-HIV response.

Oncogenic BRAF induces chronic ER stress condition resulting in increased basal autophagy and apoptotic resistance of cutaneous melanoma

The notorious unresponsiveness of metastatic cutaneous melanoma to current treatment strategies coupled with its increasing incidence constitutes a serious worldwide clinical problem. Moreover, despite recent advances in targeted therapies for patients with BRAF(V600E) mutant melanomas, acquired resistance remains a limiting factor and hence emphasises the acute need for comprehensive pre-clinical studies to increase the biological understanding of such tumours in order to develop novel effective and longlasting therapeutic strategies. Autophagy and ER stress both have a role in melanoma development/progression and chemoresistance although their real impact is still unclear. Here, we show that BRAF(V600E) induces a chronic ER stress status directly increasing basal cell autophagy. BRAF(V600E)-mediated p38 activation stimulates both the IRE1/ASK1/JNK and TRB3 pathways. Bcl-XL/Bcl-2 phosphorylation by active JNK releases Beclin1 whereas TRB3 inhibits the Akt/mTor axes, together resulting in an increase in basal autophagy. Furthermore, we demonstrate chemical chaperones relieve the BRAF(V600E)-mediated chronic ER stress status, consequently reducing basal autophagic activity and increasing the sensitivity of melanoma cells to apoptosis. Taken together, these results suggest enhanced basal autophagy, typically observed in BRAF(V600E) melanomas, is a consequence of a chronic ER stress status, which ultimately results in the chemoresistance of such tumours. Targeted therapies that attenuate ER stress may therefore represent a novel and more effective therapeutic strategy for BRAF mutant melanoma.

Molecular mechanisms of Ebola virus pathogenesis: focus on cell death

Ebola virus (EBOV) belongs to the Filoviridae family and is responsible for a severe disease characterized by the sudden onset of fever and malaise accompanied by other non-specific signs and symptoms; in 30–50% of cases hemorrhagic symptoms are present. Multiorgan dysfunction occurs in severe forms with a mortality up to 90%. The EBOV first attacks macrophages and dendritic immune cells. The innate immune reaction is characterized by a cytokine storm, with secretion of numerous pro-inflammatory cytokines, which induces a huge number of contradictory signals and hurts the immune cells, as well as other tissues. Other highly pathogenic viruses also trigger cytokine storms, but Filoviruses are thought to be particularly lethal because they affect a wide array of tissues. In addition to the immune system, EBOV attacks the spleen and kidneys, where it kills cells that help the body to regulate its fluid and chemical balance and that make proteins that help the blood to clot. In addition, EBOV causes liver, lungs and kidneys to shut down their functions and the blood vessels to leak fluid into surrounding tissues. In this review, we analyze the molecular mechanisms at the basis of Ebola pathogenesis with a particular focus on the cell death pathways induced by the virus. We also discuss how the treatment of the infection can benefit from the recent experience of blocking/modulating cell death in human degenerative diseases.

Essential versus accessory aspects of cell death: recommendations of the NCCD 2015

Cells exposed to extreme physicochemical or mechanical stimuli die in an uncontrollable manner, as a result of their immediate structural breakdown. Such an unavoidable variant of cellular demise is generally referred to as ‘accidental cell death' (ACD). In most settings, however, cell death is initiated by a genetically encoded apparatus, correlating with the fact that its course can be altered by pharmacologic or genetic interventions. ‘Regulated cell death' (RCD) can occur as part of physiologic programs or can be activated once adaptive responses to perturbations of the extracellular or intracellular microenvironment fail. The biochemical phenomena that accompany RCD may be harnessed to classify it into a few subtypes, which often (but not always) exhibit stereotyped morphologic features. Nonetheless, efficiently inhibiting the processes that are commonly thought to cause RCD, such as the activation of executioner caspases in the course of apoptosis, does not exert true cytoprotective effects in the mammalian system, but simply alters the kinetics of cellular demise as it shifts its morphologic and biochemical correlates. Conversely, bona fide cytoprotection can be achieved by inhibiting the transduction of lethal signals in the early phases of the process, when adaptive responses are still operational. Thus, the mechanisms that truly execute RCD may be less understood, less inhibitable and perhaps more homogeneous than previously thought. Here, the Nomenclature Committee on Cell Death formulates a set of recommendations to help scientists and researchers to discriminate between essential and accessory aspects of cell death.

Impaired autophagic flux is associated with increased endoplasmic reticulum stress during the development of NAFLD

The pathogenic mechanisms underlying the progression of non-alcoholic fatty liver disease (NAFLD) are not fully understood. In this study, we aimed to assess the relationship between endoplasmic reticulum (ER) stress and autophagy in human and mouse hepatocytes during NAFLD. ER stress and autophagy markers were analyzed in livers from patients with biopsy-proven non-alcoholic steatosis (NAS) or non-alcoholic steatohepatitis (NASH) compared with livers from subjects with histologically normal liver, in livers from mice fed with chow diet (CHD) compared with mice fed with high fat diet (HFD) or methionine-choline-deficient (MCD) diet and in primary and Huh7 human hepatocytes loaded with palmitic acid (PA). In NASH patients, significant increases in hepatic messenger RNA levels of markers of ER stress (activating transcription factor 4 (ATF4), glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP)) and autophagy (BCN1) were found compared with NAS patients. Likewise, protein levels of GRP78, CHOP and p62/SQSTM1 (p62) autophagic substrate were significantly elevated in NASH compared with NAS patients. In livers from mice fed with HFD or MCD, ER stress-mediated signaling was parallel to the blockade of the autophagic flux assessed by increases in p62, microtubule-associated protein 2 light chain 3 (LC3-II)/LC3-I ratio and accumulation of autophagosomes compared with CHD fed mice. In Huh7 hepatic cells, treatment with PA for 8 h triggered activation of both unfolding protein response and the autophagic flux. Conversely, prolonged treatment with PA (24 h) induced ER stress and cell death together with a blockade of the autophagic flux. Under these conditions, cotreatment with rapamycin or CHOP silencing ameliorated these effects and decreased apoptosis. Our results demonstrated that the autophagic flux is impaired in the liver from both NAFLD patients and murine models of NAFLD, as well as in lipid-overloaded human hepatocytes, and it could be due to elevated ER stress leading to apoptosis. Consequently, therapies aimed to restore the autophagic flux might attenuate or prevent the progression of NAFLD.

Caspase-2 promotes cytoskeleton protein degradation during apoptotic cell death

The caspase family of proteases cleaves large number of proteins resulting in major morphological and biochemical changes during apoptosis. Yet, only a few of these proteins have been reported to selectively cleaved by caspase-2. Numerous observations link caspase-2 to the disruption of the cytoskeleton, although it remains elusive whether any of the cytoskeleton proteins serve as bona fide substrates for caspase-2. Here, we undertook an unbiased proteomic approach to address this question. By differential proteome analysis using two-dimensional gel electrophoresis, we identified four cytoskeleton proteins that were degraded upon treatment with active recombinant caspase-2 in vitro. These proteins were degraded in a caspase-2-dependent manner during apoptosis induced by DNA damage, cytoskeleton disruption or endoplasmic reticulum stress. Hence, degradation of these cytoskeleton proteins was blunted by siRNA targeting of caspase-2 and when caspase-2 activity was pharmacologically inhibited. However, none of these proteins was cleaved directly by caspase-2. Instead, we provide evidence that in cells exposed to apoptotic stimuli, caspase-2 probed these proteins for proteasomal degradation. Taken together, our results depict a new role for caspase-2 in the regulation of the level of cytoskeleton proteins during apoptosis.

Reticulon1-C modulates protein disulphide isomerase function

Endoplasmic reticulum (ER) is the primary site for the synthesis and folding of secreted and membrane-bound proteins. Accumulation of unfolded and misfolded proteins in ER underlies a wide range of human neurodegenerative disorders. Hence, molecules regulating the ER stress response represent potential candidates as drug targets for tackling these diseases. Protein disulphide isomerase (PDI) is a chaperone involved in ER stress pathway, its activity being an important cellular defense against protein misfolding. Here, we demonstrate that human neuroblastoma SH-SY5Y cells overexpressing the reticulon protein 1-C (RTN1-C) reticulon family member show a PDI punctuate subcellular distribution identified as ER vesicles. This represents an event associated with a significant increase of PDI enzymatic activity. We provide evidence that the modulation of PDI localization and activity does not only rely upon ER stress induction or upregulation of its synthesis, but tightly correlates to an alteration in its nitrosylation status. By using different RTN1-C mutants, we demonstrate that the observed effects depend on RTN1-C N-terminal region and on the integrity of the microtubule network. Overall, our results indicate that RTN1-C induces PDI redistribution in ER vesicles, and concomitantly modulates its activity by decreasing the levels of its S-nitrosylated form. Thus RTN1-C represents a promising candidate to modulate PDI function.

Applying proteomic technology to clinical virology

Developing antiviral drugs, vaccines and diagnostic markers is still the most ambitious challenge in clinical virology. In the past few decades, data from high‐throughput technologies have allowed for the rapid development of new antiviral therapeutic strategies, thus making a profound impact on translational research. Most of the current preclinical studies in virology are aimed at evaluating the dynamic composition and localization of the protein platforms involved in various host–virus interactions. Among the different possible approaches, mass spectrometry‐based proteomics is increasingly being used to define the protein composition in subcellular compartments, quantify differential protein expression among samples, characterize protein complexes, and analyse protein post‐translational modifications. Here, we review the current knowledge of the most useful proteomic approaches in the study of viral persistence and pathogenicity, with a particular focus on recent advances in hepatitis C research.

Type 2 transglutaminase is involved in the autophagy-dependent clearance of ubiquitinated proteins

Eukaryotic cells are equipped with an efficient quality control system to selectively eliminate misfolded and damaged proteins, and organelles. Abnormal polypeptides that escape from proteasome-dependent degradation and aggregate in the cytosol can be transported via microtubules to inclusion bodies called 'aggresomes', where misfolded proteins are confined and degraded by autophagy. Here, we show that Type 2 transglutaminase (TG2) knockout mice display impaired autophagy and accumulate ubiquitinated protein aggregates upon starvation. Furthermore, p62-dependent peroxisome degradation is also impaired in the absence of TG2. We also demonstrate that, under cellular stressful conditions, TG2 physically interacts with p62 and they are localized in cytosolic protein aggregates, which are then recruited into autophagosomes, where TG2 is degraded. Interestingly, the enzyme's crosslinking activity is activated during autophagy and its inhibition leads to the accumulation of ubiquitinated proteins. Taken together, these data indicate that the TG2 transamidating activity has an important role in the assembly of protein aggregates, as well as in the clearance of damaged organelles by macroautophagy.

Molecular definitions of cell death subroutines: recommendations of the Nomenclature Committee on Cell Death 2012

In 2009, the Nomenclature Committee on Cell Death (NCCD) proposed a set of recommendations for the definition of distinct cell death morphologies and for the appropriate use of cell death-related terminology, including 'apoptosis', 'necrosis' and 'mitotic catastrophe'. In view of the substantial progress in the biochemical and genetic exploration of cell death, time has come to switch from morphological to molecular definitions of cell death modalities. Here we propose a functional classification of cell death subroutines that applies to both in vitro and in vivo settings and includes extrinsic apoptosis, caspase-dependent or -independent intrinsic apoptosis, regulated necrosis, autophagic cell death and mitotic catastrophe. Moreover, we discuss the utility of expressions indicating additional cell death modalities. On the basis of the new, revised NCCD classification, cell death subroutines are defined by a series of precise, measurable biochemical features.

Type 2 transglutaminase in Huntington's disease: a double-edged sword with clinical potential

Huntington's disease (HD) is a dominant genetic neurodegenerative disorder. The pathology affects principally neurons in the basal ganglia circuits and terminates invariably in death. There is compelling necessity for safe and effective therapeutic strategies to arrest, or even retard the progression of the pathogenesis. Recent findings indicate the autophagy-lysosome systems as appealing targets for pharmacological intervention. Autophagy exerts a critical role in controlling neuronal protein homeostasis, which is perturbed in HD, and is compromised in the pathogenesis of several neurodegenerative diseases. Type 2 transglutaminase (TG2) plays an important role both in apoptosis and autophagy regulation, and accumulates at high levels in cells under stressful conditions. TG2 inhibition, achieved either via drug treatments or genetic approaches, has been shown to be beneficial for the treatment of HD in animal models. In this review we will discuss the relevance of TG2 to the pathogenesis of HD, in an effort to define novel therapeutic avenues.

A brain-specific isoform of mitochondrial apoptosis-inducing factor: AIF2

Apoptosis-inducing factor (AIF) has important supportive as well as potentially lethal roles in neurons. Under normal physiological conditions, AIF is a vital redox-active mitochondrial enzyme, whereas in pathological situations, it translocates from mitochondria to the nuclei of injured neurons and mediates apoptotic chromatin condensation and cell death. In this study, we reveal the existence of a brain-specific isoform of AIF, AIF2, whose expression increases as neuronal precursor cells differentiate. AIF2 arises from the utilization of the alternative exon 2b, yet uses the same remaining 15 exons as the ubiquitous AIF1 isoform. AIF1 and AIF2 are similarly imported to mitochondria in which they anchor to the inner membrane facing the intermembrane space. However, the mitochondrial inner membrane sorting signal encoded in the exon 2b of AIF2 is more hydrophobic than that of AIF1, indicating a stronger membrane anchorage of AIF2 than AIF1. AIF2 is more difficult to be desorbed from mitochondria than AIF1 on exposure to non-ionic detergents or basic pH. Furthermore, AIF2 dimerizes with AIF1, thereby preventing its release from mitochondria. Conversely, it is conceivable that a neuron-specific AIF isoform, AIF2, may have been 'designed' to be retained in mitochondria and to minimize its potential neurotoxic activity.

53BP1 represses mitotic catastrophe in syncytia elicited by the HIV-1 envelope

p53 binding protein-1 (53BP1) participates in checkpoint signaling during the DNA damage response (DDR) and during mitosis. In this study we report that 53BP1 aggregates in nuclear foci within syncytia elicited by the human immunodeficiency virus (HIV)-1 envelope. 53BP1 aggregation occurs as a consequence of nuclear fusion (karyogamy (KG)). It colocalizes partially with the promyelomonocytic leukemia protein (PML), and the ataxia telangiectasia mutated kinase (ATM), the two components of the DDR that mediate apoptosis induced by the HIV-1 envelope. ATM-dependent phosphorylation of 53BP1 on serines 25 and 1778 (53BP1S25P and 53BP1S1778P) occurs at these DNA damage foci. 53BP1S25P was also detected in syncytia present in the lymph nodes or frontal brain sections from HIV-1-infected carriers, as well as in peripheral blood mononucleated cells from HIV-1-infected individuals, correlating with viral load. Knockdown of 53BP1 caused HIV-1 envelope-induced syncytia to enter abnormal mitoses, leading to their selective destruction through mitochondrion-dependent and caspase-dependent pathways. In conclusion, depletion of 53BP1 triggers the demise of HIV-1-elicited syncytia through mitotic catastrophe.

Acetylation of RTN-1C regulates the induction of ER stress by the inhibition of HDAC activity in neuroectodermal tumors

Reticulons are a family of highly conserved proteins, localized in the endoplasmic reticulum (ER) and involved in different cellular functions, such as intracellular membrane trafficking, apoptosis and nuclear envelope formation. The reticulon protein family consists of four members, but their specific functions are presently poorly understood. RTN-1C overexpression triggers apoptosis, regulating ER stress versus DNA damage-induced cell death in a mutually exclusive way. The different RTN isoforms share a C-terminal reticulon homology domain containing two hydrophobic segments and a 66-amino acid hydrophilic loop. In the C-terminal region of RTN-1C, a unique consensus sequence (GAKRH) has recently been identified, showing 100% identity with the DNA-binding domain of histone H4. In this study, we show that this sequence is essential for RTN-1C-mediated apoptosis. It is noteworthy that the lysine 204 present in this region is post-translationally modified by acetylation and that this event is associated with a significant decrease in histone deacetylase activity and contributes to RTN-1C binding to DNA. These data demonstrate a molecular mechanism by which RTN-1C controls apoptosis and indicate this protein to be a novel potential target for cancer therapy.

The adenine nucleotide translocator 1 acts as a type 2 transglutaminase substrate: implications for mitochondrial-dependent apoptosis

In this study we provide in vitro and in vivo evidence showing that the protein disulphide isomerase (PDI) activity of type 2 transglutaminase (TG2) regulates the correct assembly and function of the mitochondrial ADP/ATP transporter adenine nucleotide translocator 1 (ANT1). We demonstrate, by means of biochemical and morphological analyses, that ANT1 and TG2 physically interact in the mitochondria. Under physiological conditions, TG2's PDI activity regulates the ADP/ATP transporter function by controlling the oligomerization of ANT1. In fact, mitochondria isolated from hearts of TG2(-/-) mice exhibit increased polymerization of ANT1, paralleled by an enhanced ADP/ATP carrier activity, as compared to mitochondria belonging to TG2(+/+) mice. Interestingly, upon cell-death induction, ANT1 becomes a substrate for TG2's cross-linking activity and the lack of TG2 results in a reduction of apoptosis as well as in a marked sensitivity to the ADP/ATP exchange inhibition by atractyloside. These findings suggest a complex TG2-dependent regulation of the ADP/ATP transporter and reveal new important avenues for its potential applications in the treatment of some mitochondrial-dependent diseases, including cardiovascular and neurodegenerative diseases.

New insights on the role of apoptosis and autophagy in HIV pathogenesis

Viruses manipulate host cells to ensure their own survival and, at late stages of the viral life cycle, they kill the infected target cell to ensure their propagation. In addition, some viruses induce a bystander killing, a viral strategy to escape from the host's innate and cognate defense systems. In HIV-infection, the disabling of the immune system is initially due to the preferential depletion by apoptosis of virus-specific CD4(+) T cells in lymphoid tissues, followed by the destruction of non-infected bystander cells. Both the extrinsic and the intrinsic pathways are activated, and this is the consequence of systemic immune activation. This review presents recent developments showing that the gastrointestinal tract is the major reservoir of infected cells and the site of rapid and profound loss of CD4 T cells, and that microbial translocation from the gastrointestinal tract is the cause of immune activation. Furthermore, apoptosis mechanisms involved in HIV-induced neuropathological disorders are discussed, including the role of syncytia that involve the sequential activation of ATM, p38MAPK and p53. Finally, HIV-associated dementia (HAD) was recently found in monkey models to be linked to inhibition of autophagy in neurons, suggesting that homeostasis of autophagy is a reliable security factor for neurons, and challenging the development of new therapeutics aimed at boosting neuronal autophagy to prevent HAD.

The co-translocation of ERp57 and calreticulin determines the immunogenicity of cell death

The exposure of calreticulin (CRT) on the plasma membrane can precede anthracycline-induced apoptosis and is required for cell death to be perceived as immunogenic. Mass spectroscopy, immunofluorescence and immunoprecipitation experiments revealed that CRT co-translocates to the surface with another endoplasmic reticulum-sessile protein, the disulfide isomerase ERp57. The knockout and knockdown of CRT or ERp57 inhibited the anthracycline-induced translocation of ERp57 or CRT, respectively. CRT point mutants that fail to interact with ERp57 were unable to restore ERp57 translocation upon transfection into crt(-/-) cells, underscoring that a direct interaction between CRT and ERp57 is strictly required for their co-translocation to the surface. ERp57(low) tumor cells generated by retroviral introduction of an ERp57-specific shRNA exhibited a normal apoptotic response to anthracyclines in vitro, yet were resistant to anthracycline treatment in vivo. Moreover, ERp57(low) cancer cells (which failed to expose CRT) treated with anthracyclines were unable to elicit an anti-tumor response in conditions in which control cells were highly immunogenic. The failure of ERp57(low) cells to elicit immune responses and to respond to chemotherapy could be overcome by exogenous supply of recombinant CRT protein. These results indicate that tumors that possess an intrinsic defect in the CRT-translocating machinery become resistant to anthracycline chemotherapy due to their incapacity to elicit an anti-cancer immune response.

The involvement of cell death and survival in neural tube defects: a distinct role for apoptosis and autophagy?

Neural tube defects (NTDs), such as spina bifida (SB) or exencephaly, are common congenital malformations leading to infant mortality or severe disability. The etiology of NTDs is multifactorial with a strong genetic component. More than 70 NTD mouse models have been reported, suggesting the involvement of distinct pathogenetic mechanisms, including faulty cell death regulation. In this review, we focus on the contribution of functional genomics in elucidating the role of apoptosis and autophagy genes in neurodevelopment. On the basis of compared phenotypical analysis, here we discuss the relative importance of a tuned control of both apoptosome-mediated cell death and basal autophagy for regulating the correct morphogenesis and cell number in developing central nervous system (CNS). The pharmacological modulation of genes involved in these processes may thus represent a novel strategy for interfering with the occurrence of NTDs.

Xeno-cannibalism as an exacerbation of self-cannibalism: a possible fruitful survival strategy for cancer cells

The term self-cannibalism, or autophagy, was coined to describe the ability of the cells to cannibalize their own damaged organelles or proteins. It was morphologically described as the presence of double-membraned autophagic vesicles filled with diverse cellular materials or debris inside the cells. Hence, more recently, the presence of autophagic vacuoles has been associated with cell survival, including cell senescence and cancer and appears to be activated by nutrient deprivation. The occurrence of autophagic processes can also lead, as final event, to the death of the cell. In this review we summarize the results reported in literature on a phagic process that appears to be related to self-cannibalism: the xeno-cannibalism. This was described as the ability of certain cells, e.g. metastatic cells, to cannibalize their siblings as well as cells from the immune system. Interestingly, metastatic tumor cells are also able to engulf and digest living cells, including autologous lymphocytes that should kill them, i.e. CD8(+) cytotoxic lymphocytes. This can represent a formidable opportunity for metastatic cells to survive in adverse conditions such as those they encounter in their "journey" towards the target organ to establish a colony. Altogether these findings seem to suggest a pathogenetic role for cannibalic behavior in human pathology and point at this surprising cellular aggressiveness as an innovative pharmacological target in the clinical management of metastatic disease.

Mycobacterium tuberculosis DNA detection in soluble fraction of urine from pulmonary tuberculosis patients

SETTING

A tertiary care and research institution in Italy.

BACKGROUND

Small DNA fragments from cells dying throughout the body have been detected in urine (transrenal DNA [Tr-DNA]).

OBJECTIVE

To test the hypothesis that Mycobacterium tuberculosis Tr-DNA could be detected in the urine of pulmonary tuberculosis (TB) patients.

DESIGN

We studied 43 patients with culture-confirmed pulmonary TB with no evidence of extra-pulmonary involvement, 10 patients with pulmonary diseases other than TB and 13 healthy controls. DNA was extracted from urine and analysed by semi-nested polymerase chain reaction (PCR).

RESULTS

M. tuberculosis-specific sequences were found in the urine of 34 of 43 (79%) TB patients studied, whereas all controls were negative. The transrenal nature of M. tuberculosis DNA was demonstrated by two lines of evidence: first, separate analysis of supernatants and sediments from eight of the study patients found seven positive supernatants but only two matched positive sediments. Second, M. tuberculosis-specific sequences were amplified by semi-nested PCR with primers designed for short but not large amplicons.

CONCLUSION

Small M. tuberculosis DNA fragments may be detected in the urine of a significant proportion of patients with pulmonary TB. If these observations are confirmed by larger studies, Tr-DNA technology could represent a new approach for detecting pulmonary M. tuberculosis infection.

Targeting homeostatic mechanisms of endoplasmic reticulum stress to increase susceptibility of cancer cells to fenretinide-induced apoptosis: the role of stress proteins ERdj5 and ERp57

Endoplasmic reticulum (ER) malfunction, leading to ER stress, can be a consequence of genome instability and hypoxic tissue environments. Cancer cells survive by acquiring or enhancing survival mechanisms to counter the effects of ER stress and these homeostatic responses may be new therapeutic targets. Understanding the links between ER stress and apoptosis may be approached using drugs specifically to target ER stress responses in cancer cells. The retinoid analogue fenretinide [N-(4-hydroxyphenyl) retinamide] is a new cancer preventive and chemotherapeutic drug, that induces apoptosis of some cancer cell types via oxidative stress, accompanied by induction of an ER stress-related transcription factor, GADD153. The aim of this study was to test the hypothesis that fenretinide induces ER stress in neuroectodermal tumour cells, and to elucidate the role of ER stress responses in fenretinide-induced apoptosis. The ER stress genes ERdj5, ERp57, GRP78, calreticulin and calnexin were induced in neuroectodermal tumour cells by fenretinide. In contrast to the apoptosis-inducing chemotherapeutic drugs vincristine and temozolomide, fenretinide induced the phosphorylation of eIF2α, expression of ATF4 and splicing of XBP-1 mRNA, events that define ER stress. In these respects, fenretinide displayed properties similar to the ER stress inducer thapsigargin. ER stress responses were inhibited by antioxidant treatment. Knockdown of ERp57 or ERdj5 by RNA interference in these cells increased the apoptotic response to fenretinide. These data suggest that downregulating homeostatic ER stress responses may enhance apoptosis induced by oxidative stress-inducing drugs acting through the ER stress pathway. Therefore, ER-resident proteins such as ERdj5 and ERp57 may represent novel chemotherapeutic targets.

Conjoined lumbosacral nerve roots: observations on three cases and review of the literature

Lumbosacral nerve root anomalies are a rare group of congenital anatomical anomalies. Various types of anomalies of the lumbosacral nerve roots have been documented in the available international literature. Generally speaking, these anomalies may consist of a bifid, conjoined structure, of a transverse course or of a characteristic anastomized appearance. Firstly described as an incidental finding during autopsies or surgical procedures performed for lumbar disk herniations and often asymptomatic, lumbosacral nerve root anomalies have been more frequently described in the last years due to the advances made in radiological diagnosis (metrizamide myelography and CT, MRI). Our study comprised three patients with conjoined lumbosacral nerve roots, representing 0.25% of a total of 1200 patients who underwent lumbosacral CT/MRI procedures in the Addolorata Hospital and in the Service of Neuroradiology of the University of Rome "La Sapienza" during the last three years (March 2001-March 2004). We report our experience with three cases of conjoined lumbosacral nerve roots and analyze the most important literature on this topic. MR imaging is a better diagnostic procedure (in comparison to CT) for the differentiation of nerve root anomalies and, in particular, coronal sections furnish a precise definition of the profile of the conjoined/enlarged rootlets. In fact, the accurate information derived from MRI of multiple planes may be priceless for the preoperative and diagnostic evaluation of lumbosacral nerve root anomalies.

Mechanisms of apoptosis induction by the HIV-1 envelope

The envelope glycoprotein complex (Env) of human immunodeficiency virus-1 (HIV-1) can induce apoptosis by a cornucopia of distinct mechanisms. A soluble Env derivative, gp120, can kill cells through signals that are transmitted by chemokine receptors such as CXCR4. Cell surface-bound Env (gp120/gp41), as present on the plasma membrane of HIV-1-infected cells, can kill uninfected bystander cells expressing CD4 and CXCR4 (or similar chemokine receptors, depending on the Env variant) by at least three different mechanisms. First, a transient interaction involving the exchange of lipids between the two interacting cells ('the kiss of death') may lead to the selective death of single CD4-expressing target cells. Second, fusion of the interacting cells may lead to the formation of syncytia which then succumb to apoptosis in a complex pathway involving the activation of several kinases (cyclin-dependent kinase-1, Cdk1; checkpoint kinase-2, Chk2; mammalian target of rapamycin, mTOR; p38 mitogen-activated protein kinase, p38 MAPK; inhibitor of NF-kappaB kinase, IKK), as well as the activation of several transcription factors (NF-kappaB, p53), finally resulting in the activation of the mitochondrial pathway of apoptosis. Third, if the Env-expressing cell is at an early stage of imminent apoptosis, its fusion with a CD4-expressing target cell can precipitate the death of both cells, through a process that may be considered as contagious apoptosis and which does not involve Cdk1, mTOR, p38 nor p53, yet does involve mitochondria. Activation of some of the above- mentioned lethal signal transducers have been detected in patients' tissues, suggesting that HIV-1 may indeed trigger apoptosis through molecules whose implication in Env-induced killing has initially been discovered in vitro.

Lack of 'tissue' transglutaminase protein cross-linking leads to leakage of macromolecules from dying cells: relationship to development of autoimmunity in MRLIpr/Ipr mice

Genetic defects of the CD95 (Fas/Apo-1) receptor/ligand system, has recently been involved in the development of human and murine autoimmunity. We investigated whether a deregulation of the ;tissue' transglutaminase (tTG), a multifunctional enzyme which is part of the molecular program of apoptosis, may act as a cofactor in the development of autoimmunity. We found that MRLlpr/lpr, which are characterized by a defect in the CD95 receptor and suffer of a severe systemic lupus erythematosus-like disease, produce large amounts of circulating tTG autoantibodies. This phenomenon is paralleled by an abnormal accumulation of an inactive enzyme protein in the accessory cells of lymphoid organs. To investigate the molecular mechanisms by which tTG inhibition may contribute to the development of autoimmunity we generated a cell culture model system consisting of L929 cells stably transfected with a full length tTG cDNA. When L929 cells were killed by Tumor Necrosis Factor alpha (TNFalpha) a pronounced release of DNA and Lactate Dehydrogenase (LDH) was observed. Overexpression of tTG in these cells largely prevented the leakage of macromolecules determined by TNFalpha treatment, an effect which is abolished by inactivating the enzyme cross-linking activity by a synthetic inhibitor. These in vitro observations provided the basis to explain the increased levels of plasmatic LDH we detected in MRLlpr/lpr mice. These data suggest that lack of an active tTG may represent a cofactor in the development of autoimmunity.