Deficient Endoplasmic Reticulum-Mitochondrial Phosphatidylserine Transfer Causes Liver Disease.

Non-alcoholic fatty liver is the most common liver disease worldwide. Here, we show that the mitochondrial protein mitofusin 2 (Mfn2) protects against liver disease. Reduced Mfn2 expression was detected in liver biopsies from patients with non-alcoholic steatohepatitis (NASH). Moreover, reduced Mfn2 levels were detected in mouse models of steatosis or NASH, and its re-expression in a NASH mouse model ameliorated the disease. Liver-specific ablation of Mfn2 in mice provoked inflammation, triglyceride accumulation, fibrosis, and liver cancer. We demonstrate that Mfn2 binds phosphatidylserine (PS) and can specifically extract PS into membrane domains, favoring PS transfer to mitochondria and mitochondrial phosphatidylethanolamine (PE) synthesis. Consequently, hepatic Mfn2 deficiency reduces PS transfer and phospholipid synthesis, leading to endoplasmic reticulum (ER) stress and the development of a NASH-like phenotype and liver cancer. Ablation of Mfn2 in liver reveals that disruption of ER-mitochondrial PS transfer is a new mechanism involved in the development of liver disease.

Synthesis, and evaluation of photophysical properties of a potential DPP-derived photosensitizer for photodynamic therapy with D-A-D architecture.

The study of a macromolecule derived from DPP and triphenylamine, (DPP-BisTPA) by computational chemistry, its synthesis by direct arylation, optical characterization (UV-Vis and fluorescence) and electrochemistry (cyclic voltammetry), as well as its evaluation as a generator of reactive oxygen species indirectly, through the degradation of uric acid. The results obtained by DFT using B3LYP/6-31G (d, p) and TD-DFT using CAM-B3LYP/6-31G (d, p) reveal values of energy levels of the first singlet and triplet excited state that indicate a possible intersystem crossover and the possible generation of reactive oxygen species by a type I mechanism. The compound presents an absorption region within the phototherapeutic window. The electrochemical bandgap is 1.64 eV which suggests a behavior as a semiconductor. DPP-BisTPa were processed as hemispherical nanoparticles with a size around 100 nm, and NPOs were evaluated as a photosensitizer with a ROS generation yield of 4% using a photodynamic therapy flashlight as the light source.

Limonoids from Guarea guidonia and Cedrela odorata: Heat Shock Protein 90 (Hsp90) Modulator Properties of Chisomicine D.

Nine new limonoids (1-9) were isolated from the stem bark of Guarea guidonia (1-4) and Cedrela odorata (5-9). Their structures were elucidated using 1D and 2D NMR and MS data and chemical methods as three A2,B,D-seco-type limonoids (1-3), a mexicanolide (4), three nomilin-type (5-7) limonoids, and two limonol derivatives (8 and 9). A DFT/NMR procedure was used to define the relative configurations of 1 and 3. A surface plasmon resonance approach was used to screen the Hsp90 binding capability of the limonoids, and the A2,B,D-seco-type limonoid 8-hydro-(8S*,9S*)-dihydroxy-14,15-en-chisomicine A, named chisomicine D (1), demonstrated the highest affinity. By means of mass spectrometry data, biochemical and cellular assays, and molecular docking, 1 was found as a type of client-selective Hsp90 inhibitor binding to the C-terminus domain of the chaperone.

Pure Bladder Malignant Rhabdoid Tumor Successfully Treated With Partial Cystectomy, Radiation, and Chemotherapy: A Case Report and Review of the Literature.

BACKGROUND: Extracranial pure malignant rhabdoid tumors (MRT) are aggressive tumors that carry a poor prognosis. Bladder MRTs are very rare and only 8 cases have been reported previously. OBSERVATION: We present a case of a child with bladder MRT. Despite the aggressive nature of the bladder tumor, it was successfully treated with bladder-sparing surgery, adjuvant radiotherapy, and chemotherapy. CONCLUSIONS: Our case, and review of 8 previously reported cases, suggests that bladder MRT seems to behave less aggressively when compared with other extracranial MRTs, and bladder preserving surgery should be considered when feasible.

A role for endothelial nitric oxide synthase in intestinal stem cell proliferation and mesenchymal colorectal cancer.

BACKGROUND: Nitric oxide (NO) has been highlighted as an important agent in cancer-related events. Although the inducible nitric oxide synthase (iNOS) isoform has received most attention, recent studies in the literature indicate that the endothelial isoenzyme (eNOS) can also modulate different tumor processes including resistance, angiogenesis, invasion, and metastasis. However, the role of eNOS in cancer stem cell (CSC) biology and mesenchymal tumors is unknown. RESULTS: Here, we show that eNOS was significantly upregulated in VilCre ERT2 Apc fl/+ and VilCre ERT2 Apc fl/fl mouse intestinal tissue, with intense immunostaining in hyperproliferative crypts. Similarly, the more invasive VilCre ERT2 Apc fl/+ Pten fl/+ mouse model showed an overexpression of eNOS in intestinal tumors whereas this isoform was not expressed in normal tissue. However, none of the three models showed iNOS expression. Notably, when 40 human colorectal tumors were classified into different clinically relevant molecular subtypes, high eNOS expression was found in the poor relapse-free and overall survival mesenchymal subtype, whereas iNOS was absent. Furthermore, Apc fl/fl organoids overexpressed eNOS compared with wild-type organoids and NO depletion with the scavenger carboxy-PTIO (c-PTIO) decreased the proliferation and the expression of stem-cell markers, such as Lgr5, Troy, Vav3, and Slc14a1, in these intestinal organoids. Moreover, specific NO depletion also decreased the expression of CSC-related proteins in human colorectal cancer cells such as ß-catenin and Bmi1, impairing the CSC phenotype. To rule out the contribution of iNOS in this effect, we established an iNOS-knockdown colorectal cancer cell line. NO-depleted cells showed a decreased capacity to form tumors and c-PTIO treatment in vivo showed an antitumoral effect in a xenograft mouse model. CONCLUSION: Our data support that eNOS upregulation occurs after Apc loss, emerging as an unexpected potential new target in poor-prognosis mesenchymal colorectal tumors, where NO scavenging could represent an interesting therapeutic alternative to targeting the CSC subpopulation.

Determination of UV filters in human breast milk using turbulent flow chromatography and babies' daily intake estimation.

UV filters (UV-Fs) are a group of hormonally active chemical compounds used to protect against the deleterious effects of UVA and UVB solar radiation, which are currently present in most consumer goods (personal care products, plastics, fabrics, paints, etc). Last years the concern about these emerging contaminants has been on the rise, and increasing efforts are being taken in order to properly asses the hazard that the exposure to these compounds in the early stages of life may pose. In this study, a new method for the analysis of 11 UV-Fs residues in human breast milk samples has been developed. The method is based on turbulent flow chromatography coupled to liquid chromatography-tandem mass spectrometry (TFC-HPLC-MS/MS). The validated method was successfully applied to 79 human breast milk samples from mothers in Barcelona (Spain). Twenty-four per cent of the samples contained UV-Fs, with major contributors being oxybenzone (benzophenone 3, BP3), its metabolite 4,4'-dihydroxybenzophenone (4DHB), and UV320 showing maximum concentrations of 779.9, 73.3, and 523.6ngg-1 milk, respectively. Additionally, the plastic containers of the milks were also analysed, revealing high concentrations of BP3 and 4DHB, up to 10.6µgg-1 plastic. The calculated mean ΣUV-Fs were useful to estimate the daily intake (EDI) by babies, which were 69.1µg d-1kg-1 body weight.

New Tirucallane-Type Triterpenoids from Guarea guidonia.

The aerial parts of Guarea guidonia afforded three new tirucallane-type triterpenoids: 3,4-seco-tirucalla-4(28),8(9),24(25)-trien-7α,11α-dihydroxy-21,23-epoxy-3,11-olide, named guareolide (1: ), 3,4-seco-tirucalla-4(28),7(8),24(25)-trien-21-hydroxy-21,23-epoxy-3-oic acid, named guareoic acid A (2: ), and 3,4-seco-tirucalla-4(28),7(8),24(25)-trien-21,23-epoxy-3-oic acid, named guareoic acid B (3: ), of which 1: possessed an unusual seven-membered lactone ring. Seven known terpenes were also isolated and characterized as flindissone, 7-acetyldihydronomilin, picroquassin E, boscartol C, and cneorubins A, B, and X. Their structures were determined by spectroscopic methods including one-dimensional and two-dimensional nuclear magnetic resonance analysis and high-resolution mass spectrometry. The isolates were investigated for their potential cytotoxic activity on Jurkat, HeLa, and MCF7 cancer cell lines. Flindissone and compound 2: showed an antiproliferative activity in all cell lines. Further studies revealed that flindissone, the most active compound, induced in Jurkat and HeLa cells both cytostatic and cytotoxic responses.

Altered S-nitrosothiol homeostasis provides a survival advantage to breast cancer cells in HER2 tumors and reduces their sensitivity to trastuzumab.

The monoclonal antibody trastuzumab against HER2/neu, which is overexpressed in 15-20% of breast cancers, has clinical efficacy but many patients do not respond to initial treatment or develop resistance during treatment. Nitric oxide (NO) regulates cell signaling by targeting specific cysteine residues in proteins, forming S-nitrosothiols (SNO) in a process known as S-nitrosylation. We previously reported that molecular characteristics in breast cancer may dictate the tumor response to impaired SNO homeostasis. In the present study, we explored the role of SNO homeostasis in HER2 breast tumors. The antiproliferative action of trastuzumab in HER2-overexpressing BT-474 and SKBR-3 cells was suppressed when S-nitrosoglutathione reductase (GSNOR/ADH5) activity, which plays a key role in SNO homeostasis, was specifically inhibited with the pyrrole derivative compound N6022. Moreover, GSNOR inhibition restored the activation of survival signaling pathways involved in the resistance to anti-HER2 therapies (AKT, Src and c-Abl kinases and TrkA/NRTK1, TrkB/NRTK2, EphA1 and EphA3 receptors) and reduced the apoptotic effect of trastuzumab. Accordingly, GSNOR inhibition augmented the S-nitrosylation of apoptosis-related proteins, including Apaf-1, pSer73/63 c-Jun, calcineurin subunit α and HSF1. In agreement with in vitro data, immunohistochemical analyses of 51 breast tumors showed that HER2 expression was associated with lower expression of GSNOR protein. Moreover, gene expression analysis confirmed that high ADH5/GSNOR gene expression was associated with high patient survival rates in HER2 tumors. In conclusion, our data provide evidence of molecular mechanisms contributing to the progression of HER2+ breast cancers and could facilitate the development of therapeutic options to counteract resistance to anti-HER2 therapies.

Vascular smooth muscle cell phenotypic changes in patients with Marfan syndrome.

OBJECTIVE: Marfan's syndrome is characterized by the formation of ascending aortic aneurysms resulting from altered assembly of extracellular matrix microfibrils and chronic tissue growth factor (TGF)-ß signaling. TGF-ß is a potent regulator of the vascular smooth muscle cell (VSMC) phenotype. We hypothesized that as a result of the chronic TGF-ß signaling, VSMC would alter their basal differentiation phenotype, which could facilitate the formation of aneurysms. This study explores whether Marfan's syndrome entails phenotypic alterations of VSMC and possible mechanisms at the subcellular level. APPROACH AND RESULTS: Immunohistochemical and Western blotting analyses of dilated aortas from Marfan patients showed overexpression of contractile protein markers (α-smooth muscle actin, smoothelin, smooth muscle protein 22 alpha, and calponin-1) and collagen I in comparison with healthy aortas. VSMC explanted from Marfan aortic aneurysms showed increased in vitro expression of these phenotypic markers and also of myocardin, a transcription factor essential for VSMC-specific differentiation. These alterations were generally reduced after pharmacological inhibition of the TGF-ß pathway. Marfan VSMC in culture showed more robust actin stress fibers and enhanced RhoA-GTP levels, which was accompanied by increased focal adhesion components and higher nuclear localization of myosin-related transcription factor A. Marfan VSMC and extracellular matrix measured by atomic force microscopy were both stiffer than their respective controls. CONCLUSIONS: In Marfan VSMC, both in tissue and in culture, there are variable TGF-ß-dependent phenotypic changes affecting contractile proteins and collagen I, leading to greater cellular and extracellular matrix stiffness. Altogether, these alterations may contribute to the known aortic rigidity that precedes or accompanies Marfan's syndrome aneurysm formation.

Genetic variants in the renin-angiotensin system predict response to bevacizumab in cancer patients.

BACKGROUND: Currently, there are no predictive biomarkers for anti-angiogenic strategies in cancer, but response to anti-angiogenic drugs is associated with development of hypertension secondary to treatment. Therefore, this study explored the clinical relevance of genetic polymorphisms in some components of the renin-angiotensin system (RAS). MATERIAL AND METHODS: Genomic DNA was isolated from peripheral blood from 95 metastatic breast or colorectal cancer patients treated with bevacizumab, and AGTR1-A1166C (rs5186), AGT-M235T (rs699) SNPs and ACE I/D (rs4646994) polymorphisms were genotyped using RT-PCR. Circulating vascular endothelial grow factor and angiotensin converting enzyme (ACE) levels were analysed using ELISA kits. The antitumoral activity of bevacizumab was assayed in mice orthotopically xenografted with AGTR1-overexpressing breast cancer cells. RESULTS: The ACE IN/IN genotype was associated with a higher rate of disease progression compared to DEL/IN and DEL/DEL genotypes (36% vs. 11·1% P < 0·05). Similarly, AGTR1-1166A/A genotype was also associated with a higher rate of disease progression compared to AGTR1-1166A/C and AGTR1-1166C/C genotypes (24·4% vs. 2·7% P < 0·01). ACE IN/IN genotype was also found to be associated with shorter time to treatment failure compared to ACE IN/DEL and ACE DEL/DEL genotypes (14 weeks vs. 41·71, P = 0·033), whereas circulating ACE levels were found to be associated with a better response to bevacizumab treatment. Besides, in vivo experiments showed a significantly higher antitumoral activity of bevacizumab in tumours derived from AGTR1-overexpressing breast cancer cells. CONCLUSIONS: A higher activity of ACE-angiotensin-II-AGTR1 axis is associated with a better response to bevacizumab, supporting that the RAS can be an important source of potential predictive markers of response to anti-angiogenic drugs.

Anteromedial Petrous (Gardner's) Triangle: Surgical Anatomy and Relevance for Endoscopic Endonasal Approach to the Petrous Apex and Petroclival Region.

BACKGROUND AND OBJECTIVES: Triangular corridors have been used as reliable surgical entry points for open transcranial approaches to the petrous apex (PA) and petroclival region (PCR). The endoscopic endonasal approaches have grown rapidly in the last decade, and the indications have advanced. The knowledge of accurate and reliable anatomic landmarks through endoscopic endonasal route is essential and remain to be established. The purpose of this study was to describe the feasibility and surgical exposure of the anteromedial petrous (Gardner's) triangle as a novel corridor to the PA and PCR. METHODS: Five anatomic specimens were dissected. The PA and PCR were accessed through endoscopic endonasal approaches and contralateral transmaxillary approach. The limits of the anteromedial petrous (Gardner's) triangle were identified and dissected and associated measurements performed. RESULTS: The dissection was divided into 6 steps. The limits of the anteromedial petrous (Gardner's) triangle were identified and defined by the paraclival internal carotid artery anterolaterally, the abducens nerve posteromedially, and the petroclival synchondrosis inferiorly. Three lines were established following the limits of the triangle. The mean distance of the anterolateral limit was 10.03 mm (SD = 0.94), of the posteromedial limit was 20.06 mm (SD = 2.90), and of the inferior limit was 17.99 mm (SD = 2.99). The mean area was 87.56 mm 2 (SD = 20.06). The 3 anatomic landmarks with a critical role to safely define the triangle were the pterygosphenoidal fissure, the petrosal process of the sphenoid bone, and the petroclival synchondrosis. CONCLUSION: The anteromedial (Gardner's) triangle is a well-defined bone corridor which provides access to the entire petrous bone and petroclival junction through endoscopic endonasal route. Regardless of the anatomic variations or tumor location, the landmarks of the abducens nerve, paraclival internal carotid artery, and petroclival synchondrosis are key for understanding lateral access to tumors extending from the clivus.

Suppression of metastatic organ colonization and antiangiogenic activity of the orally bioavailable lipid raft-targeted alkylphospholipid edelfosine.

Metastasis is the leading cause of cancer mortality. Metastatic cancer is notoriously difficult to treat, and it accounts for the majority of cancer-related deaths. The ether lipid edelfosine is the prototype of a family of synthetic antitumor compounds collectively known as alkylphospholipid analogs, and its antitumor activity involves lipid raft reorganization. In this study, we examined the effect of edelfosine on metastatic colonization and angiogenesis. Using non-invasive bioluminescence imaging and histological examination, we found that oral administration of edelfosine in nude mice significantly inhibited the lung and brain colonization of luciferase-expressing 435-Lung-eGFP-CMV/Luc metastatic cells, resulting in prolonged survival. In metastatic 435-Lung and MDA-MB-231 breast cancer cells, we found that edelfosine also inhibited cell adhesion to collagen-I and laminin-I substrates, cell migration in chemotaxis and wound-healing assays, as well as cancer cell invasion. In 435-Lung and other MDA-MB-435-derived sublines with different organotropism, edelfosine induced G2/M cell cycle accumulation and apoptosis in a concentration- and time-dependent manner. Edelfosine also inhibited in vitro angiogenesis in human and mouse endothelial cell tube formation assays. The antimetastatic properties were specific to cancer cells, as edelfosine had no effects on viability in non-cancerous cells. Edelfosine accumulated in membrane rafts and endoplasmic reticulum of cancer cells, and membrane raft-located CD44 was downregulated upon drug treatment. Taken together, this study highlights the potential of edelfosine as an attractive drug to prevent metastatic growth and organ colonization in cancer therapy. The raft-targeted drug edelfosine displays a potent activity against metastatic organ colonization and angiogenesis, two major hallmarks of tumor malignancy.

Mitofusin-2 induced by exercise modifies lipid droplet-mitochondria communication, promoting fatty acid oxidation in male mice with NAFLD.

BACKGROUND AND AIM: The excessive accumulation of lipid droplets (LDs) is a defining characteristic of nonalcoholic fatty liver disease (NAFLD). The interaction between LDs and mitochondria is functionally important for lipid metabolism homeostasis. Exercise improves NAFLD, but it is not known if it has an effect on hepatic LD-mitochondria interactions. Here, we investigated the influence of exercise on LD-mitochondria interactions and its significance in the context of NAFLD. APPROACH AND RESULTS: Mice were fed high-fat diet (HFD) or HFD-0.1 % methionine and choline-deficient diet (MCD) to emulate simple hepatic steatosis or non-alcoholic steatohepatitis, respectively. In both models, aerobic exercise decreased the size of LDs bound to mitochondria and the number of LD-mitochondria contacts. Analysis showed that the effects of exercise on HOMA-IR and liver triglyceride levels were independent of changes in body weight, and a positive correlation was observed between the number of LD-mitochondria contacts and NAFLD severity and with the lipid droplet size bound to mitochondria. Cellular fractionation studies revealed that ATP-coupled respiration and fatty acid oxidation (FAO) were greater in hepatic peridroplet mitochondria (PDM) from HFD-fed exercised mice than from equivalent sedentary mice. Finally, exercise increased FAO and mitofusin-2 abundance exclusively in PDM through a mechanism involving the curvature of mitochondrial membranes and the abundance of saturated lipids. Accordingly, hepatic mitofusin-2 ablation prevented exercise-induced FAO in PDM. CONCLUSIONS: This study demonstrates that aerobic exercise has beneficial effects in murine NAFLD models by lessening the interactions between hepatic LDs and mitochondria, and by decreasing LD size, correlating with a reduced severity of NAFLD. Additionally, aerobic exercise increases FAO in PDM and this process is reliant on Mfn-2 enrichment, which modifies LD-mitochondria communication.

Binding profiles for 954 Drosophila and C. elegans transcription factors reveal tissue specific regulatory relationships.

A catalog of transcription factor (TF) binding sites in the genome is critical for deciphering regulatory relationships. Here we present the culmination of the modERN (model organism Encyclopedia of Regulatory Networks) consortium that systematically assayed TF binding events in vivo in two major model organisms, Drosophila melanogaster (fly) and Caenorhabditis elegans (worm). We describe key features of these datasets, comprising 604 TFs identifying 3.6M sites in the fly and 350 TFs identifying 0.9 M sites in the worm. Applying a machine learning model to these data identifies sets of TFs with a prominent role in promoting target gene expression in specific cell types. TF binding data are available through the ENCODE Data Coordinating Center and at https://epic.gs.washington.edu/modERNresource, which provides access to processed and summary data, as well as widgets to probe cell type-specific TF-target relationships. These data are a rich resource that should fuel investigations into TF function during development.

Short-term estimation and application of biological variation of small dense low-density lipoproteins in healthy individuals.

BACKGROUND: A number of methods have been developed to measure small dense low-density lipoprotein cholesterol (sd-LDL-C) to evaluate atherogenic risk in the population. However, to our knowledge there are no reports about the biologic variability of these lipoproteins. Therefore, the aim of this work was to estimate sd-LDL-C biological variability, and with this information establish quality specifications, index of individuality (II) and reference change values (RCV). METHODS: To estimate within- and between-subject biological variability, sd-LDL-C in serum was measured in 24 individuals (11 female and 13 male) for 5 consecutive days and then, at 2 and 3 weeks. Quality specifications, II, and RCVs were estimated according to procedures described. RESULTS: Total within- and between-subject biological variability, expressed as coefficient of variation, was 9.1% and 20%. Meanwhile, within- and between-biological variability in female and men was 10.9% and 6.7%, and 22% and 17%, respectively. Desirable quality specification to the sd-LDL-C method was 4.6% for analytical imprecision, bias 5.5% and total allowable error of 11.4%; the II was 0.46 and the RCV (calculated at 95% and 99% of significance) was 27.1% and 35.7%, for the total data. CONCLUSIONS: Short-term biological variability components were determined, and then used to estimate quality specifications, II and RCV for sd-LDL-C precipitation assay. To our knowledge, this is one of the first reports about sd-LDL-C biological variability, so that this information can be used as a starting point to develop long-term studies of biological variability for sd-LDL-C.

Development of a preclinical therapeutic model of human brain metastasis with chemoradiotherapy.

Currently, survival of breast cancer patients with brain metastasis ranges from 2 to 16 months. In experimental brain metastasis studies, only 10% of lesions with the highest permeability exhibited cytotoxic responses to paclitaxel or doxorubicin. Therefore, radiation is the most frequently used treatment, and sensitizing agents, which synergize with radiation, can improve the efficacy of the therapy. In this study we used 435-Br1 cells containing the fluorescent protein (eGFP) gene and the photinus luciferase (PLuc) gene to develop a new brain metastatic cell model in mice through five in vivo/in vitro rounds. BR-eGFP-CMV/Luc-V5 brain metastatic cells induce parenchymal brain metastasis within 60.8 ± 13.8 days of intracarotid injection in all mice. We used this model to standardize a preclinical chemoradiotherapy protocol comprising three 5.5 Gy fractions delivered on consecutive days (overall dose of 16.5 Gy) which improved survival with regard to controls (60.29 ± 8.65 vs. 47.20 ± 11.14). Moreover, the combination of radiotherapy with temozolomide, 60 mg/Kg/day orally for five consecutive days doubled survival time of the mice 121.56 ± 52.53 days (Kaplan-Meier Curve, p < 0.001). This new preclinical chemoradiotherapy protocol proved useful for the study of radiation response/resistance in brain metastasis, either alone or in combination with new sensitizing agents.

Chlamydia Trachomatis Masquerading as Scrotal Masses in Adolescents.

OBJECTIVE: To present a case series of 3 post-pubertal adolescent males with Chlamydia trachomatis presenting as scrotal masses. Scrotal masses are worrisome for malignancy, especially when imaging confirms intratesticular lesions. However, there are benign conditions which may mimic testicular cancer. Some of these conditions may not be readily considered in the pediatric population. This phenomenon is rare in the pediatric population, and this represents only the second report in the literature of this finding. METHODS: Three cases of adolescent males who presented with a scrotal mass were reviewed. Traditional work up was performed, and results are reviewed. RESULTS: Median age for these patients was 16 years (range 16-17). All patients underwent scrotal ultrasound confirming intratesticular lesions. Two of the 3 patients denied sexual activity within the past year. Two patients underwent orchiectomy after counseling and shared decision making, with both specimens demonstrating no malignancy. All 3 patients were eventually diagnosed with Chlamydia trachomatis and treated with appropriate antibiotic therapy. CONCLUSION: Adolescent males who are sexually active can present with Chlamydia trachomatis infection masquerading as a scrotal mass. It is important to consider infectious etiologies in this patient group as it has been documented that many adolescents are hesitant to admit to sexual activity. Thus, routine sexually transmitted infection (STI) screening warrants consideration, and testicular preservation should be sought when it is a viable management option.

Maintenance of S-nitrosothiol homeostasis plays an important role in growth suppression of estrogen receptor-positive breast tumors.

INTRODUCTION: Protein denitrosylation by thioredoxin reductase (TrxR) is key for maintaining S-nitrosothiol (SNO) homeostasis, although its role in tumor progression is unknown. Therefore, the present study aimed to assess the role of altered SNO homeostasis in breast cancer cells. METHODS: The impairment of SNO homeostasis in breast cancer cells was achieved with the highly specific TrxR inhibitor auranofin and/or exposure to S-nitroso-L-cysteine. S-nitrosylated proteins were detected using the biotin switch assay. Estrogen receptor (ER) alpha knockdown was achieved using RNA silencing technologies and subcellular localization of ERα was analyzed by confocal microscopy. The Oncomine database was explored for TrxR1 (TXNRD1) expression in breast tumors and TrxR1, ER and p53 expression was analyzed by immunohistochemistry in a panel of breast tumors. RESULTS: The impairment of SNO homeostasis enhanced cell proliferation and survival of ER+ MCF-7 cells, but not of MDA-MB-231 (ER-, mut p53) or BT-474 (ER+, mut p53) cells. This enhanced cell growth and survival was associated with Akt, Erk1/2 phosphorylation, and augmented cyclin D1 expression and was abolished by the ER antagonist fulvestrant or the p53 specific inhibitor pifithrin-α. The specific silencing of ERα expression in MCF-7 cells also abrogated the growth effect of TrxR inhibition. Estrogenic deprivation in MCF-7 cells potentiated the pro-proliferative effect of impaired SNO homeostasis. Moreover, the subcellular distribution of ERα was altered, with a predominant nuclear localization associated with phosphorylation at Thr311 in those cells with impaired SNO homeostasis. The impairment of SNO homeostasis also expanded a cancer stem cell-like subpopulation in MCF-7 cells, as indicated by the increase of percentage of CD44+ cells and the augmented capability to form mammospheres in vitro. Notably, ER+ status in breast tumors was significantly associated with lower TXNDR1 mRNA expression and immunohistochemical studies confirmed this association, particularly when p53 abnormalities were absent. CONCLUSION: The ER status in breast cancer may dictate tumor response to different nitrosative environments. Impairment of SNO homeostasis confers survival advantages to ER+ breast tumors, and these molecular mechanisms may also participate in the development of resistance against hormonal therapies that arise in this type of mammary tumors.

Risk Factors and Reconstruction Techniques for Persistent Cerebrospinal Fluid Leak in Patients Undergoing Endoscopic Endonasal Approach to the Posterior Fossa.

Background High-flow skull base dural defects are associated with an increased risk of postoperative cerebrospinal fluid (CSF) leaks. Objective This study aimed to identify the risk factors for persistent postoperative CSF leak after endoscopic endonasal surgery (EES) and determine the ideal reconstruction strategy after initial failed repair. Methods Patients with CSF leak after intradural EES between October 2000 and February 2017 were identified. Cases with persistent CSF leak were compared with patients with similar pathologic diagnosis without a persistent leak to identify additional risk factors. Results Two hundred and twenty-three out of 3,232 patients developed postoperative CSF leak. Persistent leaks requiring more than one postoperative repair occurred in 7/223 patients (3.1%). All seven had undergone intradural approach to the posterior fossa for resection of recurrent/residual clival chordomas. This group was matched with 25 patients with recurrent/residual clival chordoma who underwent EES without postoperative CSF leak (control group). Age, gender, history of diabetes, smoking, or radiotherapy were not statistically different between the groups. Obesity (body mass index > 30) was significantly more common in the group with persistent leak (86%) compared with controls (36%) ( p = 0.02). All patients with a persistent CSF leak developed meningitis ( p = 0.001). Five patients with persistent leak required a pericranial flap to achieve definitive repair. Conclusion Multiple recurrent CSF leak after EES primarily occurs following resection of recurrent/residual posterior fossa chordoma. Obesity is a major risk factor and meningitis is universal with persistent leak. Flap necrosis may play a role in the development of persistent CSF leaks, and the use of secondary vascularized flaps, specifically extracranial-pericranial flaps, should be considered as an early rescue option in obese patients.

Keyhole Endoscopic-Assisted Transcervical Approach to the Upper and Middle Retrostyloid Parapharyngeal Space: An Anatomic Feasibility Study.

Objectives The aim of this study was to describe the anatomical nuances, feasibility, limitations, and surgical exposure of the parapharyngeal space (PPS) through a novel minimally invasive keyhole endoscopic-assisted transcervical approach (MIKET). Design Descriptive cadaveric study. Setting Microscopic and endoscopic high-quality images were taken comparing the MIKET approach with a conventional combined transmastoid infralabyrinthine transcervical approach. Participants Five colored latex-injected specimens (10 sides). Main Outcome Measures Qualitative anatomical descriptions in four surgical stages; quantitative and semiquantitative evaluation of relevant landmarks. Results A 5 cm long inverted hockey stick incision was designed to access a corridor posterior to the parotid gland after independent mobilization of nuchal and cervical muscles to expose the retrostyloid PPS. The digastric branch of the facial nerve, which runs 16.5 mm over the anteromedial part of the posterior belly of the digastric muscle before piercing the parotid fascia, was used as a landmark to identify the main trunk of the facial nerve. MIKET corridor was superior to the crossing of the accessory nerve over the internal jugular vein within 17.3 mm from the jugular process. Further exposure of the occipital condyle, vertebral artery, and the jugular bulb was achieved. Conclusion The novel MIKET approach provides in the cadaver straightforward access to the upper and middle retrostyloid PPS through a natural corridor without injuring important neurovascular structures. Our work sets the anatomical nuances and limitations that should guide future clinical studies to prove its efficacy and safety either as a stand-alone procedure or as an adjunct to other approaches, such as the endonasal endoscopic approach.