Inhibition of the AURKA/YAP1 axis is a promising therapeutic option for overcoming cetuximab resistance in colorectal cancer stem cells.

BACKGROUND: Primary resistance to anti-EGFR therapies affects 40% of metastatic colorectal cancer patients harbouring wild-type RAS/RAF. YAP1 activation is associated with this resistance, prompting an investigation into AURKA's role in mediating YAP1 phosphorylation at Ser397, as observed in breast cancer. METHODS: We used transcriptomic analysis along with in vitro and in vivo models of RAS/RAF wild-type CRC to study YAP1 Ser397 phosphorylation as a potential biomarker for cetuximab resistance. We assessed cetuximab efficacy using CCK8 proliferation assays and cell cycle analysis. Additionally, we examined the effects of AURKA inhibition with alisertib and created a dominant-negative YAP1 Ser397 mutant to assess its impact on cancer stem cell features. RESULTS: The RAS/RAF wild-type CRC models exhibiting primary resistance to cetuximab prominently displayed elevated YAP1 phosphorylation at Ser397 primarily mediated by AURKA. AURKA-induced YAP1 phosphorylation was identified as a key trigger for cancer stem cell reprogramming. Consequently, we found that AURKA inhibition had the capacity to effectively restore cetuximab sensitivity and concurrently suppress the cancer stem cell phenotype. CONCLUSIONS: AURKA inhibition holds promise as a therapeutic approach to overcome cetuximab resistance in RAS/RAF wild-type colorectal cancer, offering a potential means to counter the development of cancer stem cell phenotypes associated with cetuximab resistance.

Surgery for acute subdural hematoma: the value of pre-emptive decompressive craniectomy by propensity score analysis.

BACKGROUND: Acute subdural hematomas (ASDH) are found frequently following traumatic brain injury (TBI) and they are considered the most lethal type of mass lesions. The decision to perform a procedure to evacuate ASDH and the approach, either via craniotomy or decompressive craniectomy (DC), remains controversial. METHODS: We reviewed a prospectively collected series of 343 moderate to severe TBI patients in whom ASDH was the main lesion (ASDH volumes ≥10 cc). Patients with early comfort measures (early mortality prediction >50% and not ICP monitored), bilateral ASDH or the presence of another intracranial hematoma with volumes exceeding two times the volume of the ASDH were excluded. Among them, 112 were managed conservatively, 65 underwent ASDH evacuation by craniotomy and 166 by DC (103 pre-emptive DC, 63 obligatory DC). We calculated the average treatment effect by propensity score (PS) analysis using the following covariates: age, year, hypoxia, shock, pupils, major extracranial injury, motor score, midline shift, ASDH volume, swelling, intraventricular and subarachnoid hemorrhage presence. Then, multivariable binary regression and ordinal logistic regression analysis were performed to estimate associations between predictors and mortality and 12 months-GOS respectively. The patients' inverse probability weights were included as an independent variable in both regression models. RESULTS: The main variables associated with outcome were year, age, falls from patient´s own height, hypoxia, early deterioration, pupillary abnormalities, basal cistern effacement, compliance to ICP monitoring guidelines and type of surgical approach (craniotomy and pre-emptive DC). CONCLUSIONS: According to sliding dichotomy analysis, we found that patients in the intermediate or worst bands of unfavorable outcome prognosis seemed to achieve better than expected outcome if they underwent pre-emptive DC rather than craniotomy.

Patients awaiting surgery for neurosurgical diseases during the first wave of the COVID-19 pandemic in Spain: a multicentre cohort study.

OBJECTIVES: The large number of infected patients requiring mechanical ventilation has led to the postponement of scheduled neurosurgical procedures during the first wave of the COVID-19 pandemic. The aims of this study were to investigate the factors that influence the decision to postpone scheduled neurosurgical procedures and to evaluate the effect of the restriction in scheduled surgery adopted to deal with the first outbreak of the COVID-19 pandemic in Spain on the outcome of patients awaiting surgery. DESIGN: This was an observational retrospective study. SETTINGS: A tertiary-level multicentre study of neurosurgery activity between 1 March and 30 June 2020. PARTICIPANTS: A total of 680 patients awaiting any scheduled neurosurgical procedure were enrolled. 470 patients (69.1%) were awaiting surgery because of spine degenerative disease, 86 patients (12.6%) due to functional disorders, 58 patients (8.5%) due to brain or spine tumours, 25 patients (3.7%) due to cerebrospinal fluid (CSF) disorders and 17 patients (2.5%) due to cerebrovascular disease. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was mortality due to any reason and any deterioration of the specific neurosurgical condition. Second, we analysed the rate of confirmed SARS-CoV-2 infection. RESULTS: More than one-quarter of patients experienced clinical or radiological deterioration. The rate of worsening was higher among patients with functional (39.5%) or CSF disorders (40%). Two patients died (0.4%) during the waiting period, both because of a concurrent disease. We performed a multivariate logistic regression analysis to determine independent covariates associated with maintaining the surgical indication. We found that community SARS-CoV-2 incidence (OR=1.011, p<0.001), degenerative spine (OR=0.296, p=0.027) and expedited indications (OR=6.095, p<0.001) were independent factors for being operated on during the pandemic. CONCLUSIONS: Patients awaiting neurosurgery experienced significant collateral damage even when they were considered for scheduled procedures.

Accelerated 3D whole-brain T1, T2, and proton density mapping: feasibility for clinical glioma MR imaging.

PURPOSE: Advanced MRI-based biomarkers offer comprehensive and quantitative information for the evaluation and characterization of brain tumors. In this study, we report initial clinical experience in routine glioma imaging with a novel, fully 3D multiparametric quantitative transient-state imaging (QTI) method for tissue characterization based on T1 and T2 values. METHODS: To demonstrate the viability of the proposed 3D QTI technique, nine glioma patients (grade II-IV), with a variety of disease states and treatment histories, were included in this study. First, we investigated the feasibility of 3D QTI (6:25 min scan time) for its use in clinical routine imaging, focusing on image reconstruction, parameter estimation, and contrast-weighted image synthesis. Second, for an initial assessment of 3D QTI-based quantitative MR biomarkers, we performed a ROI-based analysis to characterize T1 and T2 components in tumor and peritumoral tissue. RESULTS: The 3D acquisition combined with a compressed sensing reconstruction and neural network-based parameter inference produced parametric maps with high isotropic resolution (1.125 × 1.125 × 1.125 mm3 voxel size) and whole-brain coverage (22.5 × 22.5 × 22.5 cm3 FOV), enabling the synthesis of clinically relevant T1-weighted, T2-weighted, and FLAIR contrasts without any extra scan time. Our study revealed increased T1 and T2 values in tumor and peritumoral regions compared to contralateral white matter, good agreement with healthy volunteer data, and high inter-subject consistency. CONCLUSION: 3D QTI demonstrated comprehensive tissue assessment of tumor substructures captured in T1 and T2 parameters. Aiming for fast acquisition of quantitative MR biomarkers, 3D QTI has potential to improve disease characterization in brain tumor patients under tight clinical time-constraints.

Dysregulated lipid metabolism in hepatocellular carcinoma cancer stem cells.

According to the stem cell theory for cancer, hepatocellular carcinomas are sustained by a group of cancer stem cells (CSCs) which are responsible for resistance to chemotherapy. In the present study we aimed to examine lipid metabolism in cancer stem cells induced by long-term treatment with sorafenib and its relationship with acquisition of a CSC-like phenotype. Two cell lines (HepG2SF1 and Huh7SF1) were generated by incubation with a step-wise increase of sorafenib concentrations for 10 months. These cell lines displayed stem-like characteristics like increase in the expression of ABCB1A, Nanog and Oct4 as well as an E-cadherin/N-cadherin switch. HepG2SF1 and Huh7SF1 cells showed intracellular accumulation of neutral lipids, assessed by flow cytometry and confocal microscopy. The exam of lipid metabolism revealed that HepG2SF1 and Huh7SF1 cells increased the expression of the enzymes involved in de novo lipid synthesis ATP-citrate lyase (ACLY), acetyl-CoA carboxylase (ACC) and fatty acid synthase (FASN) and that of the fatty acid transporter CD36. In addition, these CSC-like cells had enhanced expression of the lipogenic transcription factor SREBP1c. Analysis of the key metabolic sensor AMP-activated kinase (AMPK) demonstrated that both AMPK phosphorylation and levels were decreased in the CSC-like cells compared to their parental cells. Interestingly, transfection of HepG2SF1 and Huh7SF1 cells with AMPK, restored the levels of the lipogenic enzymes and SREBP1c and decreased the intracellular lipid accumulation. Furthermore, AMPK transfection decreased the stemness markers and inhibited the E-cadherin/N-cadherin switch. Targeting AMPK and lipid metabolism of hepatocellular cancer stem cells is a promising strategy to face stemness and chemotherapy resistance.

Chitinase-3-Like Protein 1, Serum Amyloid A1, C-Reactive Protein, and Procalcitonin Are Promising Biomarkers for Intracranial Severity Assessment of Traumatic Brain Injury: Relationship with Glasgow Coma Scale and Computed Tomography Volumetry.

OBJECTIVE: The volume and location of intracranial hematomas are well-known prognostic factors for traumatic brain injury. The aim of this study was to determine the relationship of serum biomarkers S100ß, glial fibrillary acidic protein, neuron-specific enolase, total tau, phosphorylated neurofilament heavy chain, serum amyloid A1 (SAA1), C-reactive protein, procalcitonin (PCT), and chitinase-3-like protein 1 (YKL-40) with traumatic brain injury severity and the amount and location of hemorrhagic traumatic lesions. METHODS: A prospective observational cohort of 115 patients with a Glasgow Coma Scale (GCS) score of 3-15 were evaluated. Intracranial lesion volume was measured from the semiautomatic segmentation of hematoma on computed tomography using Analyze software. The establishment of possible biomarker cutoff points for intracranial lesion detection was estimated using the Youden Index (J) obtained from the area under the receiver operating characteristic curve. RESULTS: SAA1, YKL-40, PCT, and S100ß showed the most robust association with level of consciousness, both with total GCS and motor score. Biomarkers significantly correlated with volumetric measurements of subdural hematoma, traumatic subarachnoid hemorrhage, intraparenchymal hemorrhage, intraventricular hemorrhage, and total amount of bleeding. The type of intracranial hemorrhage was associated with various release patterns of neurobiochemical markers. CONCLUSIONS: YKL-40, SAA1, C-reactive protein, and PCT combined with S100ß were the most promising biomarkers to determine the presence, location, and extent of traumatic intracranial lesions. Combination of biomarkers further increased the discriminatory capacity for the detection of intracranial bleeding.

Variability of Clinical and Angiographic Results Based on the Treatment Preference (Endovascular or Surgical) of Centers Participating in the Subarachnoid Hemorrhage Database of the Working Group of the Spanish Society of Neurosurgery.

OBJECTIVES: Since the introduction of endovascular treatment for cerebral aneurysms, hospitals in which subarachnoid hemorrhage is treated show different availability and/or preferences towards both treatment modalities. The main aim is to evaluate the clinical and angiographic results according to the hospital's treatment preferences applied. METHODS: This study was conducted based on use of the subarachnoid hemorrhage database of the Vascular Pathology Group of the Spanish Neurosurgery Society. Centers were classified into 3 subtypes according to an index in the relationship between endovascular and surgical treatment as: endovascular preference, high endovascular preference, and elevated surgical preference. The clinical results and angiographic results were evaluated among the 3 treatment strategies. RESULTS: From November 2004 to December 2017, 4282 subarachnoid hemorrhage patients were selected for the study: 630 (14.7%) patients from centers with surgical preference, 2766 (64.6%) from centers with endovascular preference, and 886 (20.7%) from centers with high endovascular preference. The surgical preference group obtained the best angiographic results associated with a greater complete exclusion (odds ratio: 1.359; 95% confidence interval: 1.025-1.801; P = 0.033). The surgical preference subgroup obtained the best outcome at discharge (65.45%), followed by the high endovascular preference group (61.5%) and the endovascular preference group (57.8%) (odds ratio: 1.359; 95% confidence interval: 1.025-1.801; P = 0.033). CONCLUSIONS: In Spain, there is significant variability in aneurysm exclusion treatment in aneurysmal subarachnoid hemorrhage. Surgical centers offer better results for both surgical and endovascular patients. A multidisciplinary approach and the maintenance of an elevated quality of surgical competence could be responsible for these results.

Capsaicin Targets Lipogenesis in HepG2 Cells Through AMPK Activation, AKT Inhibition and PPARs Regulation.

Obesity, a major risk factor for chronic diseases such as type 2 diabetes (T2D), represents a serious primary health problem worldwide. Dietary habits are of special interest to prevent and counteract the obesity and its associated metabolic disorders, including lipid steatosis. Capsaicin, a pungent compound of chili peppers, has been found to ameliorate diet-induced obesity in rodents and humans. The purpose of this study was to examine the effect of capsaicin on hepatic lipogenesis and to delineate the underlying signaling pathways involved, using HepG2 cells as an experimental model. Cellular neutral lipids, stained with BODIPY493/503, were quantified by flow cytometry, and the protein expression and activity were determined by immunoblotting. Capsaicin reduced basal neutral lipid content in HepG2 cells, as well that induced by troglitazone or by oleic acid. This effect of capsaicin was prevented by dorsomorphin and GW9662, pharmacological inhibitors of AMPK and PPARγ, respectively. In addition, capsaicin activated AMPK and inhibited the AKT/mTOR pathway, major regulators of hepatic lipogenesis. Furthermore, capsaicin blocked autophagy and increased PGC-1α protein. These results suggest that capsaicin behaves as an anti-lipogenic compound in HepG2 cells.

Targeting AMP-activated kinase impacts hepatocellular cancer stem cells induced by long-term treatment with sorafenib.

Hepatocellular carcinoma (HCC) is the third leading cause of cancer death worldwide. HCC treatment is hindered by the frequent emergence of chemoresistance to the multikinase inhibitor sorafenib, which has been related to the presence of cancer stem cells (CSCs) that self-renew and often escape therapy. The key metabolic sensor AMP-activated kinase (AMPK) has recently been recognized as a tumour growth regulator. In this study, we aimed to elucidate the role of AMPK in the development of a stem cell phenotype in HCC cells. To this end, we enriched the CSC population in HCC cell lines that showed increased expression of drug resistance (ALDH1A1, ABCB1A) and stem cell (CD133, Nanog, Oct4, alpha fetoprotein) markers and demonstrated their stemness phenotype. These cells were refractory to sorafenib-induced cell death. We report that sorafenib-resistant cells had lower levels of total and phosphorylated AMPK as well as its downstream substrate, ACC, compared with the parental cells. Interestingly, AMPK knockdown with siRNA or inhibition with dorsomorphin increased the expression of stem cell markers in parental cells and blocked sorafenib-induced cell death. Conversely, the upregulation of AMPK, either by transfection or by pharmacological activation with A-769662, decreased the expression of ALDH1A1, ABCB1A, CD133, Nanog, Oct4, and alpha fetoprotein, and restored sensitivity to sorafenib. Analysis of the underlying mechanism points to hypoxia-inducible factor HIF-1α as a regulator of stemness. In vivo studies in a xenograft mouse model demonstrated that stem-like cells have greater tumourigenic capacity. AMPK activation reduced xenograft tumour growth and decreased the expression of stem cell markers. Taken together, these results indicate that AMPK may serve as a novel target to overcome chemoresistance in HCC.

Combination of the natural product capsaicin and docetaxel synergistically kills human prostate cancer cells through the metabolic regulator AMP-activated kinase.

BACKGROUND: Current chemotherapy for castration-resistant prostate cancer is established on taxane-based compounds like docetaxel. However, eventually, the development of toxic side effects and resistance limits the therapeutic benefit being the major concern in the treatment of prostate cancer. Combination therapies in many cases, enhance drug efficacy and delay the appearance of undesired effects, representing an important option for the treatment of castration-resistant prostate cancer. In this study, we tested the efficacy of the combination of docetaxel and capsaicin, the pungent ingredient of hot chili peppers, on prostate cancer cells proliferation. METHODS: Prostate cancer LNCaP and PC3 cell lines were used in this study. Levels of total and phosphorylated forms of Akt, mTOR, S6, LKB1, AMPK and ACC were determined by Western blot. AMPK, LKB1 and Akt knock down was performed by siRNA. PTEN was overexpressed by transient transfection with plasmids. Xenograft prostate tumors were induced in nude mice and treatments (docetaxel and capsaicin) were administered intraperitoneally. Statistical analyses were performed with GraphPad software. Combination index was calculated with Compusyn software. RESULTS: Docetaxel and capsaicin synergistically inhibited the growth of LNCaP and PC3 cells, with a combination index lower than 1 for most of the combinations tested. Co-treatment with docetaxel and capsaicin notably decreased Akt and its downstream targets mTOR and S6 phosphorylation. Overexpression of PTEN phosphatase abrogated the synergistic antiproliferative effect of docetaxel and capsaicin. The combined treatment also increased the phosphorylation of AMP-activated kinase (AMPK) and the phosphorylation of its substrate ACC. In addition, pharmacological inhibition of AMPK with dorsomorphin (compound C) as well as knock down by siRNA of AMPK or its upstream kinase LKB1, abolished the synergy of docetaxel and capsaicin. Mechanistically, we showed that the synergistic anti-proliferative effect may be attributed to two independent effects: Inhibition of the PI3K/Akt/mTOR signaling pathway by one side, and AMPK activation by the other. In vivo experiments confirmed the synergistic effects of docetaxel and capsaicin in reducing the tumor growth of PC3 cells. CONCLUSION: Combination of docetaxel and capsaicin represents a therapeutically relevant approach for the treatment of Prostate Cancer.

The red pepper's spicy ingredient capsaicin activates AMPK in HepG2 cells through CaMKKß.

Capsaicin is a natural compound present in chili and red peppers and the responsible of their spicy flavor. It has recently provoked interest because of its antitumoral effects in many cell types although its action mechanism is not clearly understood. As metabolic dysregulation is one of the hallmarks of cancer cells and the key metabolic sensor in the AMP-activated kinase (AMPK), in this study we explored the ability of capsaicin to modulate AMPK activity. We found that capsaicin activated AMPK in HepG2 cells by increasing AMPK phosphorylation and its downstream target ACC. Mechanistically, we determined that capsaicin activated AMPK through the calcium/calmodulin-dependent protein kinase kinase ß, CaMKKß as either the CaMKK inhibitor STO-609 or CaMKK knock down with siRNA abrogated the activation of AMPK. Moreover, capsaicin decreased cell viability, inhibited Akt/mTOR pathway and increased reactive oxygen species (ROS) in HepG2 cells. AMPK activation was involved in the underpinning mechanism of capsaicin-induced cell death.

Inhibition of 53BP1 favors homology-dependent DNA repair and increases CRISPR-Cas9 genome-editing efficiency.

Programmable nucleases, such as Cas9, are used for precise genome editing by homology-dependent repair (HDR). However, HDR efficiency is constrained by competition from other double-strand break (DSB) repair pathways, including non-homologous end-joining (NHEJ). We report the discovery of a genetically encoded inhibitor of 53BP1 that increases the efficiency of HDR-dependent genome editing in human and mouse cells. 53BP1 is a key regulator of DSB repair pathway choice in eukaryotic cells and functions to favor NHEJ over HDR by suppressing end resection, which is the rate-limiting step in the initiation of HDR. We screened an existing combinatorial library of engineered ubiquitin variants for inhibitors of 53BP1. Expression of one variant, named i53 (inhibitor of 53BP1), in human and mouse cells, blocked accumulation of 53BP1 at sites of DNA damage and improved gene targeting and chromosomal gene conversion with either double-stranded DNA or single-stranded oligonucleotide donors by up to 5.6-fold. Inhibition of 53BP1 is a robust method to increase efficiency of HDR-based precise genome editing.

Symptomatic ptosis cerebelli after suboccipital craniectomy in a patient with severe brain trauma.

PRIMARY OBJECTIVE: To report the first case of symptomatic cerebellar ptosis after a large suboccipital craniectomy in a patient with severe brain trauma and a review of the literature. PATIENT AND METHODS: A 36-year-old man suffered severe traumatic brain injury after a four-metre fall. He underwent a large suboccipital craniectomy because his computed tomography scan revealed a posterior fossa subdural haematoma and cerebellar swelling. Four weeks after admission, he developed communicating hydrocephalus, and a ventriculoperitoneal shunt was placed. Although he experienced good recovery, seven months after the trauma he complained of cephalea, dizziness, recurrent vomiting and diplopia. Magnetic resonance imaging (MRI) showed descent of the cerebellum through a wide bone defect. RESULTS: We performed a posterior fossa cranioplasty after other causes of delayed worsening were ruled out, such as shunt malfunction, overdrainage and ischaemic lesions. The patient improved, and a post-operative MRI confirmed the upward migration of the cerebellum. CONCLUSIONS: Cerebellar ptosis must be considered in cases of delayed symptoms after large suboccipital craniectomy regardless of pathology. Posterior fossa cranioplasty to provide structural support to slumped cerebellum can improve or resolve symptoms.

[Trends in computed tomography characteristics, intracranial pressure monitoring and surgical management in severe traumatic brain injury: Analysis of a data base of the past 25 years in a neurosurgery department]. / Evolución temporal en las características de la tomografía computarizada, presión intracraneal y tratamiento quirúrgico en el traumatismo craneal grave: análisis de la base de datos de los últimos 25 años en un servicio de neurocirugía.

OBJECTIVE: To describe the radiological characteristics, surgical indications, procedures, and intracranial pressure monitoring of a representative cohort of severe traumatic brain injury (sTBI) cases collected over the past 25years, and to analyse the changes that have occurred by dividing the period into 3 equal time periods. METHODS: An observational cohort study was conducted on consecutive adult patients (>14years of age) with severe closed TBI (Glasgow Coma Scale score [GCS]≤8) who were admitted during the first 48hours after injury to the Hospital 12 de Octubre from 1987 to 2012. The most relevant radiological findings, surgical procedures, and intracranial monitoring indications reported in the literature were defined and compared in 3 equal time periods (1987-1995, 1996-2004, and 2005-2014). RESULTS: A significant increase was observed in subdural haematomas with lesions over 25cc, and midline shift in the last period of time. The incidence of subarachnoid haemorrhage increased significantly with time. There was a progression to a worse computed tomography (CT) classification from the initial CT scan in 33% of cases. Surgery was performed on 721 (39.4%) patients. Early surgery (<12hours) was performed on 585 (81.1%) patients, with the most frequent being for extra-cerebral mass lesions (subdural and epidural haematomas), whereas delayed surgery (>12hours) was most frequently performed due to an intracerebral haematoma. Surgical treatment, both early and late was significantly lower with respect to the first time period. Decompressive craniectomy with evacuation of the mass lesion was the preferred procedure in the last time period. Intracranial pressure monitoring (ICP) was carried out on 1049 (57.3%) patients, with a significantly higher frequency in the second period of time. There was adherence to Guidelines in 64.4% of cases. Elevated/uncontrolled ICP was more significant in the first time period. CONCLUSIONS: As a result of the epidemiological changes seen in traumatic brain injury, a different pattern of morphological injury is described, as depicted in the CT, leading to a difference in practice during this period of observation.

Hyperpolarized 13C Metabolic Magnetic Resonance Spectroscopy and Imaging.

In the past decades, new methods for tumor staging, restaging, treatment response monitoring, and recurrence detection of a variety of cancers have emerged in conjunction with the state-of-the-art positron emission tomography with 18F-fluorodeoxyglucose ([18F]-FDG PET). 13C magnetic resonance spectroscopic imaging (13CMRSI) is a minimally invasive imaging method that enables the monitoring of metabolism in vivo and in real time. As with any other method based on 13C nuclear magnetic resonance (NMR), it faces the challenge of low thermal polarization and a subsequent low signal-to-noise ratio due to the relatively low gyromagnetic ratio of 13C and its low natural abundance in biological samples. By overcoming these limitations, dynamic nuclear polarization (DNP) with subsequent sample dissolution has recently enabled commonly used NMR and magnetic resonance imaging (MRI) systems to measure, study, and image key metabolic pathways in various biological systems. A particularly interesting and promising molecule used in 13CMRSI is [1-13C]pyruvate, which, in the last ten years, has been widely used for in vitro, preclinical, and, more recently, clinical studies to investigate the cellular energy metabolism in cancer and other diseases. In this article, we outline the technique of dissolution DNP using a 3.35 T preclinical DNP hyperpolarizer and demonstrate its usage in in vitro studies. A similar protocol for hyperpolarization may be applied for the most part in in vivo studies as well. To do so, we used lactate dehydrogenase (LDH) and catalyzed the metabolic reaction of [1-13C]pyruvate to [1-13C]lactate in a prostate carcinoma cell line, PC3, in vitro using 13CMRSI.

Mammalian polymerase θ promotes alternative NHEJ and suppresses recombination.

The alternative non-homologous end-joining (NHEJ) machinery facilitates several genomic rearrangements, some of which can lead to cellular transformation. This error-prone repair pathway is triggered upon telomere de-protection to promote the formation of deleterious chromosome end-to-end fusions. Using next-generation sequencing technology, here we show that repair by alternative NHEJ yields non-TTAGGG nucleotide insertions at fusion breakpoints of dysfunctional telomeres. Investigating the enzymatic activity responsible for the random insertions enabled us to identify polymerase theta (Polθ; encoded by Polq in mice) as a crucial alternative NHEJ factor in mammalian cells. Polq inhibition suppresses alternative NHEJ at dysfunctional telomeres, and hinders chromosomal translocations at non-telomeric loci. In addition, we found that loss of Polq in mice results in increased rates of homology-directed repair, evident by recombination of dysfunctional telomeres and accumulation of RAD51 at double-stranded breaks. Lastly, we show that depletion of Polθ has a synergistic effect on cell survival in the absence of BRCA genes, suggesting that the inhibition of this mutagenic polymerase represents a valid therapeutic avenue for tumours carrying mutations in homology-directed repair genes.

The polypyrimidine tract-binding protein affects coronavirus RNA accumulation levels and relocalizes viral RNAs to novel cytoplasmic domains different from replication-transcription sites.

The coronavirus (CoV) discontinuous transcription mechanism is driven by long-distance RNA-RNA interactions between transcription-regulating sequences (TRSs) located at the 5' terminal leader (TRS-L) and also preceding each mRNA-coding sequence (TRS-B). The contribution of host cell proteins to CoV transcription needs additional information. Polypyrimidine tract-binding protein (PTB) was reproducibly identified in association with positive-sense RNAs of transmissible gastroenteritis coronavirus (TGEV) TRS-L and TRS-B by affinity chromatography and mass spectrometry. A temporal regulation of PTB cytoplasmic levels was observed during infection, with a significant increase from 7 to 16 h postinfection being inversely associated with a decrease in viral replication and transcription. Silencing the expression of PTB with small interfering RNA in two cell lines (Huh7 and HEK 293T) led to a significant increase of up to 4-fold in mRNA levels and virus titer, indicating a negative effect of PTB on CoV RNA accumulation. During CoV infection, PTB relocalized from the nucleus to novel cytoplasmic structures different from replication-transcription sites in which stress granule markers T-cell intracellular antigen-1 (TIA-1) and TIA-1-related protein (TIAR) colocalized. PTB was detected in these modified stress granules in TGEV-infected swine testis cells but not in stress granules induced by oxidative stress. Furthermore, viral genomic and subgenomic RNAs were detected in association with PTB and TIAR. These cytoplasmic ribonucleoprotein complexes might be involved in posttranscriptional regulation of virus gene expression.

Pannus resolution after occipitocervical fusion in a non-rheumatoid atlanto-axial instability.

Periodontoid pseudotumor or pannus is considered to be an inflammatory mass most frequently associated with rheumatoid arthritis. Transoral resection of the pannus has been the treatment of choice for patients with associated myelopathy, followed in many instances by posterior stabilization. However, some authors have reported resolution of pannus associated with rheumatoid arthritis and other forms of chronic atlanto-axial instability only after posterior stabilization. We report a case of a 69-year-old man who presented with a rapidly progressing myelopathy due to a retro-odontoid mass produced by chronic atlanto-axial instability associated with an occipital assimilation of C1 and tight posterior fossa. An urgent posterior fossa craniectomy followed by occipitocervical fixation was performed. After surgery, the patient's clinical condition improved and 1 year after surgery was asymptomatic, walked without any help and had normal strength. Control MR showed complete resolution of the retro-odontoid pannus.

Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing syndrome treated with microvascular decompression of the trigeminal nerve: case report.

OBJECTIVE AND IMPORTANCE: Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing syndrome is a very rare disorder characterized by short-lasting neuralgiform unilateral pain affecting the orbital-periorbital area and associated with autonomic phenomena consisting mainly of conjunctival injection, tearing, and rhinorrhea. Treatment of this condition is difficult; many drugs and surgical procedures have been tried with variable results. In the literature, two cases have been described with short-term response to microvascular decompression of the trigeminal root. We present the case of a patient with short-lasting unilateral neuralgiform headache with conjunctival injection and tearing syndrome who remains asymptomatic 2 years after microvascular decompression. CLINICAL PRESENTATION: A 56-year-old woman was referred to our clinic because she had experienced pain in the distribution of the first left trigeminal branch during the previous 2 years. She experienced paroxysms lasting from a few seconds to 1 to 2 minutes superimposed over a dull sensation of pain involving the same territory. The paroxysms had no refractory period and were triggered by touching the eye or the left side of the face, chewing, yawning, washing her hair, and even by light. Although the paroxysms were triggered by light touch or chewing, she was able to talk or touch herself while having the paroxysm. During pain attacks, she experienced tearing and ipsilateral conjunctival injection, eyelid edema and rhinorrhea, as well as intense photophobia. A magnetic resonance imaging scan revealed a vascular structure distorting and compressing the trigeminal root. INTERVENTION: The patient underwent microvascular decompression of the trigeminal root. At surgery, there was clear compression of the trigeminal root by a superior cerebellar artery loop that was resolved by interposing a Teflon patch. The patient awoke from the operation without pain, and all the accompanying signs and symptoms, such as photophobia, disappeared. The postoperative course was uneventful, and 2 years after treatment, the patient remains asymptomatic. CONCLUSION: Microvascular decompression could be an alternative therapeutic approach to this rare syndrome.