ATM and KAT5 safeguard replicating chromatin against formaldehyde damage.

Many carcinogens damage both DNA and protein constituents of chromatin, and it is unclear how cells respond to this compound injury. We examined activation of the main DNA damage-responsive kinase ATM and formation of DNA double-strand breaks (DSB) by formaldehyde (FA) that forms histone adducts and replication-blocking DNA-protein crosslinks (DPC). We found that low FA doses caused a strong and rapid activation of ATM signaling in human cells, which was ATR-independent and restricted to S-phase. High FA doses inactivated ATM via its covalent dimerization and formation of larger crosslinks. FA-induced ATM signaling showed higher CHK2 phosphorylation but much lower phospho-KAP1 relative to DSB inducers. Replication blockage by DPC did not produce damaged forks or detectable amounts of DSB during the main wave of ATM activation, which did not require MRE11. Chromatin-monitoring KAT5 (Tip60) acetyltransferase was responsible for acetylation and activation of ATM by FA. KAT5 and ATM were equally important for triggering of intra-S-phase checkpoint and ATM signaling promoted recovery of normal human cells after low-dose FA. Our results revealed a major role of the KAT5-ATM axis in protection of replicating chromatin against damage by the endogenous carcinogen FA.

Formaldehyde Is a Potent Proteotoxic Stressor Causing Rapid Heat Shock Transcription Factor 1 Activation and Lys48-Linked Polyubiquitination of Proteins.

Endogenous and exogenous formaldehyde (FA) has been linked to cancer, neurotoxicity, and other pathophysiologic effects. Molecular and cellular mechanisms that underlie FA-induced damage are poorly understood. In this study, we investigated whether proteotoxicity is an important, unrecognized factor in cell injury caused by FA. We found that irrespective of their cell cycle phases, all FA-treated human cells rapidly accumulated large amounts of proteins with proteasome-targeting K48-linked polyubiquitin, which was comparable with levels of polyubiquitination in proteasome-inhibited MG132 controls. Both nuclear and cytoplasmic proteins were damaged and underwent K48-polyubiquitination. There were no significant changes in the nonproteolytic K63-polyubiquitination of soluble and insoluble cellular proteins. FA also rapidly induced nuclear accumulation and Ser326 phosphorylation of the main heat shock-responsive transcription factor HSF1, which was not a result of protein polyubiquitination. Consistent with the activation of the functional heat shock response, FA strongly elevated the expression of HSP70 genes. In contrast to the responsiveness of the cytoplasmic protein damage sensor HSF1, FA did not activate the unfolded protein response in either the endoplasmic reticulum or mitochondria. Inhibition of HSP90 chaperone activity increased the levels of K48-polyubiquitinated proteins and diminished cell viability after FA treatment. Overall, our results indicate that FA is a strong proteotoxic agent, which helps explain its diverse pathologic effects, including injury in nonproliferative tissues.

Proteasome activity is important for replication recovery, CHK1 phosphorylation and prevention of G2 arrest after low-dose formaldehyde.

Formaldehyde (FA) is a human carcinogen with numerous sources of environmental and occupational exposures. This reactive aldehyde is also produced endogenously during metabolism of drugs and other processes. DNA-protein crosslinks (DPCs) are considered to be the main genotoxic lesions for FA. Accumulating evidence suggests that DPC repair in high eukaryotes involves proteolysis of crosslinked proteins. Here, we examined a role of the main cellular proteolytic machinery proteasomes in toxic responses of human lung cells to low FA doses. We found that transient inhibition of proteasome activity increased cytotoxicity and diminished clonogenic viability of FA-treated cells. Proteasome inactivation exacerbated suppressive effects of FA on DNA replication and increased the levels of the genotoxic stress marker γ-H2AX in normal human cells. A transient loss of proteasome activity in FA-exposed cells also caused delayed perturbations of cell cycle, which included G2 arrest and a depletion of S-phase populations at FA doses that had no effects in control cells. Proteasome activity diminished p53-Ser15 phosphorylation but was important for FA-induced CHK1 phosphorylation, which is a biochemical marker of DPC proteolysis in replicating cells. Unlike FA, proteasome inhibition had no effect on cell survival and CHK1 phosphorylation by the non-DPC replication stressor hydroxyurea. Overall, we obtained evidence for the importance of proteasomes in protection of human cells against biologically relevant doses of FA. Biochemically, our findings indicate the involvement of proteasomes in proteolytic repair of DPC, which removes replication blockage by these highly bulky lesions.

Production and characterization of the ectodomain of E2 envelope glycoprotein of hepatitis C virus folded in the presence of full-length E1 glycoprotein.

Hepatitis C virus (HCV) envelope glycoproteins, E1 and E2, are involved in the first steps of virus infection. The E2 ectodomain can be produced as an isolated form (E2661). However, there is some concern about its proper conformation and the role that E1 can play as a chaperone for the folding of E2. In order to verify this fact we have expressed a chimeric protein (E1tmbE2) based on the full-length E1 sequence followed by the E2 ectodomain using the baculovirus-insect cells system. The E2 ectodomain is folded in the presence of the E1, proteolytically processed by cellular proteases and secreted to cell culture media (E2661p), while the E1 protein is retained into the cell due to its transmembrane sequence. The purification of E2661p from culture media was facilitated by a His tag introduced in its amino terminus. Both E2661 and E2661p glycoproteins shared very similar structural features, monitored by spectroscopic and antigenic studies. Moreover, their functional properties, tested by means of CD81 binding, were almost indistinguishable, indicating that the E2 ectodomain constitutes an independent folding unit.

Toll-like receptors 3, 4 and 9 in hepatocellular carcinoma: Relationship with clinicopathological characteristics and prognosis.

AIM: Hepatocellular carcinoma (HCC) is in the 10 leading cancer types, being difficult to detect as most of patients who develop this tumor have no symptoms other than those related to their long-standing liver disease. The liver is constantly exposed to bacterial products, viral infection, alcohol or other products, which may be the cause of chronic liver damage, and thus an increasing risk for HCC. Toll-like receptors (TLR) have gained an extraordinary interest in cancer research due to their role in several biological processes such as innate immune responses, the induction of adaptive immune responses, regulation of inflammation, would healing and carcinogenesis. Therefore, the aim of this study was to investigate the expression and clinical relevance of TLR3, 4 and 9 in HCC. METHODS: The expression levels of TLR3, TLR4 and TLR9 were analyzed in tumors from 30 patients with HCC. The analysis was performed by immunohistochemistry. Results were correlated with various clinicopathological findings and with overall survival. RESULTS: TLR3 was significantly high in large tumors (>4 cm in diameter) compared with small tumors (P < 0.05). Our results demonstrated that patients whose tumors showed both TLR4 and TLR9 positive immunostaining had poor prognosis. In addition, TLR9 expression by fibroblast-like cells was significantly associated with a shortened overall survival (P = 0.015). CONCLUSION: The results demonstrated an association between TLR3, TLR4 and TLR9 expression and tumor aggressiveness and poor prognosis in HCC.

Antibiotic discontinuation through an antibiotic treatment optimization program in emergency department patients with low suspicion of infection.

INTRODUCTION: One of the most important strategies of PROA in the Emergency Department (ED) is the accurate diagnosis of infection to avoid inappropriate prescription. Our objective is to evaluate patients who receive antibiotics despite not having objective data of infection. METHODS: We carried out a cross-sectional study of patients admitted to the ED of the Hospital Universitario Fundación Alcorcón in which it was recommended to suspend the antibiotic through the PROA. Clinical and epidemiological characteristics and 30-day follow-up were analyzed to assess readmissions and mortality. RESULTS: 145 patients were analyzed. It was recommended to suspend the antibiotic in 25. 44% of them had a diagnosis of urinary infection. The suspension recommendation was accepted by 88%. No patient died and one was readmitted. CONCLUSIONS: An important percentage of patients are prescribed antibiotics despite not having infection criteria, the clinical evolution after suspension of antibiotics was favorable.

20S immunoproteasomes remove formaldehyde-damaged cytoplasmic proteins suppressing caspase-independent cell death.

Immunoproteasomes are known for their involvement in antigen presentation. However, their broad tissue presence and other evidence are indicative of nonimmune functions. We examined a role for immunoproteasomes in cellular responses to the endogenous and environmental carcinogen formaldehyde (FA) that binds to cytosolic and nuclear proteins producing proteotoxic stress and genotoxic DNA-histone crosslinks. We found that immunoproteasomes were important for suppression of a caspase-independent cell death and the long-term survival of FA-treated cells. All major genotoxic responses to FA, including replication inhibition and activation of the transcription factor p53 and the apical ATM and ATR kinases, were unaffected by immunoproteasome inactivity. Immunoproteasome inhibition enhanced activation of the cytosolic protein damage sensor HSF1, elevated levels of K48-polyubiquitinated cytoplasmic proteins and increased depletion of unconjugated ubiquitin. We further found that FA induced the disassembly of 26S immunoproteasomes, but not standard 26S proteasomes, releasing the 20S catalytic immunoproteasome. FA-treated cells also had higher amounts of small activators PA28αß and PA28γ bound to 20S particles. Our findings highlight the significance of nonnuclear damage in FA injury and reveal a major role for immunoproteasomes in elimination of FA-damaged cytoplasmic proteins through ubiquitin-independent proteolysis.

The deletion of residues 268-292 of E1 impairs the ability of HCV envelope proteins to induce pore formation.

We have obtained a chimeric protein containing the ectodomains of hepatitis C virus (HCV) envelope proteins but lacking the region 268-292 of E1. All its structural properties are coincident with those of the corresponding full length chimera. The deleted and entire chimeras were compared in terms of their membrane destabilizing properties. No differences were found in their ability to induce vesicle aggregation and lipid mixing but the deleted chimera showed a reduced capacity to promote leakage. The role of the deletion was also studied by obtaining HCV pseudoparticles (HCVpp). Both E1 and E2, and also the E1 deleted mutant, were incorporated into HCVpp to a similar level. However, HCVpp containing the E1 deleted protein are almost unable to infect Huh7 cells. These results point to the involvement of the region 268-292 in the formation of pores in the membrane necessary for the complete fusion of the membranes.

DNA double-strand breaks by Cr(VI) are targeted to euchromatin and cause ATR-dependent phosphorylation of histone H2AX and its ubiquitination.

Hexavalent chromium is a human respiratory carcinogen that undergoes intracellular activation in vivo primarily via reduction with ascorbate. Replication of Cr-adducted DNA triggers mismatch repair that generates toxic DNA double-strand breaks (DSBs) as secondary lesions. Here, we examined the intranuclear distribution of chromate-induced breaks and a central DSB signaling branch targeting histone H2AX. Using ascorbate-restored cells (H460 human lung epithelial cells, normal human lung and normal mouse embryonic fibroblasts (MEFs)), we found that Cr(VI) produced a typical DSB-associated spectrum of H2AX modifications, including its Ser139-phosphorylated (known as γH2AX) and mono- and diubiquitinated forms. However, whereas canonical DSB signaling relies on ATM, the formation of γH2AX and its ubiquitinated products by Cr(VI) was dependent on ATR kinase. Based on the established mode of ATR activation, this suggests that Cr-induced DSB are not blunt-ended and likely contain single-stranded tails. Confocal imaging with markers of active and inactive chromatin revealed a selective formation of Cr-induced DSB in euchromatin of mouse and human cells. In contrast to DSB, Cr-DNA adducts were produced in both types of chromatin. The euchromatin targeting of Cr-induced DSB makes these lesions particularly dangerous by increasing the probability of deleting active tumor suppressors and producing oncogenic translocations. Accumulation of transcription-inhibiting ubiquitinated forms of γH2AX in euchromatin is expected to contribute to the ability of Cr(VI) to suppress upregulation of inducible genes.

Analysis of the expression of interleukins, interferon ß, and nuclear factor-κ B in prostate cancer and their relationship with biochemical recurrence.

There are accumulating epidemiological, experimental, and genetic data supporting that prostate inflammation may contribute to prostate carcinogenesis, and several inflammatory-related molecules have been linked to tumorigenesis and prognosis in several tumors. The aim of this study was to evaluate tumor expression of inflammatory-related factors in prostate carcinomas and their possible relationship with biochemical recurrence (elevation of prostate-specific antigen serum levels). An immunohistochemical study was conducted using tissue microarrays and specific antibodies against interleukin-1ß (IL-1ß), IL-6, IL-10, IL-17, interferon ß (IFNß), and nuclear factor-κ B (NF-κB). Determinations in cancer specimens from 118 patients with primary prostate cancer (78 without and 40 with recurrence during the follow-up period) were performed. Immunostaining for all the studied proteins was localized both in tumor cells and in stromal cells in the majority of tumors. High-score values for IL-1ß or low-score values for IFNß were significantly associated with biochemical recurrence. The analysis defined a score value of 160 for IL-1ß and of 170 for IFNß as the optimal cutoff points that identified 32.7% and 73.2% of patients, respectively, having high probability of biochemical recurrence. Multivariate analysis according to a Cox model indicated that the cutoff point 170 for IFNß (P=0.035) was an independent factor associated with biochemical recurrence in patients with prostate cancer. Both IL-1ß and IFNß may be new biomarkers to distinguish high-risk/low-risk patients with prostate cancer, and to select appropriate therapeutic approaches.

Prediction of metastatic breast cancer in non-sentinel lymph nodes based on metalloprotease-1 expression by the sentinel lymph node.

AIMS: Sentinel lymph node (SLN) biopsy is the current standard axillary approach for patients with clinically node-negative breast cancer. If the SLN is positive, is still also standard in most centres to proceed with a complete axillary dissection to predict the remaining nodes affectation, despite of SLN is the only positive lymph node in 50-68% of cases. If we could identify them, these patients could be spared a complete axillary dissection. METHODS: Elevated expression of specific matrix metalloproteases (MMPs) and their inhibitors (TIMPs) by stromal mononuclear inflammatory cells (MICs) of primary tumours is significantly associated with distant metastasis development in breast cancer. In the present study we first identified candidate MMPs/TIMPs associated with axillary metastasis in a preliminary group (n=50), and subsequently examined the potential of their expression in the SLN for predicting the status of the remaining nodes, in 105 patients with intraoperative SLN-assessment. RESULTS: MMP-1 expression by MICs from SLNs was significantly associated with metastatic spread to non-SLNs. Moreover, in all cases with negative MMP-1 expression by MICs from SLNs, the remaining non-SLNs were not affected (p<0.0001). Therefore, we demonstrate that MMP-1 expression by MICs from SLNs had 100% sensitivity, 100% negative-predictive value and 61.5% specificity to predict non-SLNs status. CONCLUSION: This is the first time that tumour spread to the remaining axillary nodes has been predicted from molecular features of the SLN(s). If confirmed in larger studies, patients could be spared the morbidity associated with an unnecessary complete lymphadenectomy.

Suspensión de antibióticos a través de un programa de optimización de tratamiento antibiótico en pacientes atendidos en Urgencias con baja sospecha de infección / Antibiotic discontinuation through an antibiotic treatment optimization program in emergency department patients with low suspicion of infection

Introducción: Una de las estrategias más importantes de los PROA en los Servicios de Urgencias (SU) es el diagnóstico adecuado de infección para evitar la prescripción inadecuada. Nuestro objetivo es evaluar a los pacientes que reciben antibiótico a pesar de no tener datos objetivos de infección. Métodos: Realizamos un estudio transversal de los pacientes ingresados en el SU del Hospital Universitario Fundación Alcorcón durante 2 meses (mayo del 2019 y marzo del 2021) en los que se recomendó suspender el antibiótico a través del PROA. Se analizaron las características clínicas y epidemiológicas, y el seguimiento a 30 días para valorar los reingresos y la mortalidad. Resultados: Se analizaron 145 pacientes. Se recomendó suspender el antibiótico en 25. El 44% de ellos tenían diagnóstico de infección urinaria. La recomendación de suspensión se aceptó en el 88%. Ningún paciente falleció y uno reingresó. Conclusiones: Un porcentaje importante de pacientes tenían prescrito antibiótico a pesar de no tener criterios de infección, siendo la evolución clínica tras la de prescripción favorable.(AU)

Introduction: One of the most important strategies of PROA in the Emergency Department (ED) is the accurate diagnosis of infection to avoid inappropriate prescription. Our objective is to evaluate patients who receive antibiotics despite not having objective data of infection. Methods: We carried out a cross-sectional study of patients admitted to the ED of the Hospital Universitario Fundación Alcorcón in which it was recommended to suspend the antibiotic through the PROA. Clinical and epidemiological characteristics and 30-day follow-up were analyzed to assess readmissions and mortality. Results: 145 patients were analyzed. It was recommended to suspend the antibiotic in 25. 44% of them had a diagnosis of urinary infection. The suspension recommendation was accepted by 88%. No patient died and one was readmitted. Conclusions: An important percentage of patients are prescribed antibiotics despite not having infection criteria, the clinical evolution after suspension of antibiotics was favorable.(AU)