Identification of tyrosine brominated extracellular matrix proteins in normal and fibrotic lung tissues.

Peroxidasin (PXDN) is a secreted heme peroxidase that catalyzes the oxidative crosslinking of collagen IV within the extracellular matrix (ECM) via intermediate hypobromous acid (HOBr) synthesis from hydrogen peroxide and bromide, but recent findings have also suggested alternative ECM protein modifications by PXDN, including incorporation of bromide into tyrosine residues. In this work, we sought to identify the major target proteins for tyrosine bromination by HOBr or by PXDN-mediated oxidation in ECM from mouse teratocarcinoma PFHR9 cells. We detected 61 bromotyrosine (BrY)-containing peptides representing 23 proteins in HOBr-modified ECM from PFHR9 cells, among which laminins displayed the most prominent bromotyrosine incorporation. Moreover, we also found that laminin α1, laminin ß1, and tubulointerstitial nephritis antigen-like (TINAGL1) contained BrY in untreated PFHR9 cells, which depended on PXDN. We extended these analyses to lung tissues from both healthy mice and mice with experimental lung fibrosis, and in lung tissues obtained from human subjects. Analysis of ECM-enriched mouse lung tissue extracts showed that 83 ECM proteins were elevated in bleomycin-induced fibrosis, which included various collagens and laminins, and PXDN. Similarly, mRNA and protein expression of PXDN and laminin α/ß1 were enhanced in fibrotic mouse lung tissues, and also in mouse bone-marrow-derived macrophages or human fibroblasts stimulated with transforming growth factor ß1, a profibrotic growth factor. We identified 11 BrY-containing ECM proteins, including collagen IV α2, collagen VI α1, TINAGL1, and various laminins, in both healthy and mouse fibrotic lung tissues, although the relative extent of tyrosine bromination of laminins was not significantly increased during fibrosis. Finally, we also identified 7 BrY-containing ECM proteins in human lung tissues, again including collagen IV α2, collagen VI α1, and TINAGL1. Altogether, this work demonstrates the presence of several bromotyrosine-modified ECM proteins, likely involving PXDN, even in normal lung tissues, suggesting a potential biological function for these modifications.

Association of sleep duration and sleep quality with gestational diabetes mellitus in pregnant women after treatment with assisted reproductive technology: A birth cohort study.

Maternal sleep is closely related to subsequent gestational diabetes mellitus (GDM) in natural pregnancies. However, whether this connection exists in pregnant women conceiving with the help of assisted reproductive technology (ART) has not been confirmed. Hence, in this study, we evaluated whether early pregnancy sleep duration or sleep quality is associated with gestational diabetes mellitus in ART-pregnant women, as well as the influence of maternal age on this association. This prospective birth cohort study included 856 pregnant women who successfully conceived with the help of ART treatment. The sleep parameters of ART-pregnant women were assessed using the Pittsburgh Sleep Quality Index (PSQI) in early pregnancy. We explored the association between sleep and the risk of gestational diabetes mellitus using an unconditional binary logistic regression model. Different models were constructed to examine the robustness of the estimation by incorporating different confounding factors. Multivariable logistic regression revealed that sleep duration of more than 10 h among ART-pregnant women was significantly associated with the risk of GDM, and the association between sleep duration and gestational diabetes mellitus varied by maternal age. We found an increased risk of subsequent gestational diabetes mellitus with increasing sleep duration only in pregnant women aged <35 years. Additionally, no statistically significant association between sleep quality and gestational diabetes mellitus was found in this study. In conclusion, excessive sleep duration (≥10 h) is associated with a high risk of gestational diabetes mellitus in pregnant women who conceived with the help of assisted reproductive technology, and maternal age may modify this effect.

A multiprotein signaling complex sustains AKT and mTOR/S6K activity necessary for the survival of cancer cells undergoing stress.

Cancer cells encounter stresses during tumor progression and metastatic spread, however, how they survive these challenges is not fully understood. We now identify a mechanism for cancer cell survival through the discovery of a multiprotein signaling complex that includes the GTPase Cdc42, the Cdc42 GEF/effector protein Dock7, AKT, mTOR and the mTORC1 regulatory partners TSC1, TSC2, and Rheb. This pro-survival signaling complex sustains the activated state of AKT by preventing its dephosphorylation at Ser473 during serum starvation, resulting in a low but critical activation of a Raptor-independent mTOR/S6K activity. We demonstrate that the Dock7 DHR1 domain, previously of unknown function, is responsible for preserving AKT phosphorylation through an interaction requiring its C2-like motif. Collectively, these findings help address long-standing questions of how Cdc42 signals mTOR activation by elucidating the unique functions of its signaling partner Dock7 as an AKT regulator necessary for resistance to anoikis and apoptosis in cancer cells.

Trajectories of maternal D-dimer are associated with the risk of developing adverse maternal and perinatal outcomes: A prospective birth cohort study.

OBJECTIVE: To assess the relationships of maternal D-dimer trajectories with the risk of developing adverse maternal and perinatal outcomes (AMPOs). METHODS: A prospective birth cohort study was conducted in China, and 7,095 women who had singleton birth were included. The latent class growth model was used to determine the maternal D-dimer trajectory. RESULTS: Three maternal D-dimer trajectories were identified: (1) slight increase (43.6%), (2) rapid rise (51.3%), (3) sustained high (5.1%). Compared to pregnant women with a slight increase in D-dimer trajectory, the risk of gestational diabetes mellitus, placenta previa, macrosomia, large for gestational age (LGA), and increased postpartum bleeding was significantly increased in those with a rapid rise trajectory (adjusted OR = 1.22, 2.00, 1.80, and 1.56, adjusted ß = 15.92 âˆ¼ 25.1 ml, respectively, P < 0.05), and women with a sustained high trajectory also demonstrated a relatively elevated risk of macrosomia and LGA (adjusted OR = 2.11 and 1.82, respectively, P < 0.05). While the odds of pregnancy-induced hypertension, low birth weight, and small for gestational age in pregnant women with the rapid rise D-dimer trajectory and fetal distress in those with sustained high trajectory exhibited a reduction (adjusted OR = 0.62, 0.38, 0.54, and 0.64, respectively, P < 0.05). CONCLUSION: This study highlights the influence of inappropriate maternal D-dimer trajectories on the risk of AMPOs.

Diet-induced obesity worsens allergen-induced type 2/type 17 inflammation in airways by enhancing DUOX1 activation.

More than 50% of people with asthma in the United States are obese, and obesity often worsens symptoms of allergic asthma and impairs response to treatment. Based on previously established roles of the epithelial NADPH oxidase DUOX1 in allergic airway inflammation, we addressed the potential involvement of DUOX1 in altered allergic inflammation in the context of obesity. Intranasal house dust mite (HDM) allergen challenge of subjects with allergic asthma induced rapid secretion of IL-33, then IL-13, into the nasal lumen, responses that were significantly enhanced in obese asthmatic subjects (BMI >30). Induction of diet-induced obesity (DIO) in mice by high-fat diet (HFD) feeding similarly enhanced acute airway responses to intranasal HDM challenge, particularly with respect to secretion of IL-33 and type 2/type 3 cytokines, and this was associated with enhanced epithelial DUOX1 expression and was avoided in DUOX1-deficient mice. DIO also enhanced DUOX1-dependent features of chronic HDM-induced allergic inflammation. Although DUOX1 did not affect overall weight gain by HFD feeding, it contributed to glucose intolerance, suggesting a role in glucose metabolism. However, glucose intolerance induced by short-term HFD feeding, in the absence of adiposity, was not sufficient to alter HDM-induced acute airway responses. DIO was associated with enhanced presence of the adipokine leptin in the airways, and leptin enhanced DUOX1-dependent IL-13 and mucin production in airway epithelial cells. In conclusion, augmented inflammatory airway responses to HDM in obesity are associated with increases in airway epithelial DUOX1, and by increased airway epithelial leptin signaling.

First-Trimester Triglyceride-Glucose Index and Risk of Pregnancy-Related Complications: A Prospective Birth Cohort Study in Southeast China.

Purpose: To evaluate the relationships of the triglyceride-glucose (TyG) index with pregnancy-related complications (PRCs) and to clarify the predictability of the TyG index for PRCs. Patients and Methods: Totally of 11,387 women with a singleton pregnancy were prospectively followed until after delivery. Maternal fasting lipids and glucose concentration were measured in the first trimester (11 weeks gestation on average). The TyG index was calculated as ln [triglyceride (mg/dL) × fasting plasma glucose (mg/dL)/2]. We used generalized linear models to calculate the relative risks and 95% confidence intervals. Receiver-operating characteristic curve analysis was employed to assess the ability of the TyG index to predict the risks of PRCs. Results: Smooth spline reveals that the probability of gestational diabetes mellitus (GDM) is intensified with the increasing TyG index. Multivariate logistic regression adjusted for risk factors demonstrates a 1-unit and a 1-SD increment in the TyG index raises the risk of GDM by 3.63 and 1.57 times, respectively. Identically, the risk of GDM maximizes in the TyG quintile 5 (OR: 3.14; 95% CI: 2.55~3.85) relative to the lowest TyG index group. However, no association between TyG index and the risk of other PRCs was observed after full adjustment. The area under receiver operating characteristic curves is 0.647 (95% CI: 0.632-0.66) for GDM, and the optimal predictive cut-off is 8.55, with a specificity of 0.679 and sensitivity of 0.535. Conclusion: The first-trimester TyG index is significantly associated with the risk of incident GDM, while the relationships between the TyG index and other PRCs need further exploration.

The lag-effects of meteorological factors and air pollutants on child respiratory diseases in Fuzhou, China.

Background: The effects of meteorological factors and air pollutants on respiratory diseases (RDs) were various in different populations according to the demographic characteristics, and children were considered a vulnerable population. Previous studies were mainly based in cities with serious air pollution. This study aimed to qualify the lag effects of meteorological factors and air pollution on respiratory diseases among children under 18 years old in Fuzhou. Methods: Meteorological data, air pollutants concentrations and hospital admission data of Fujian Maternity and Child Health Hospital between 2015 and 2019 were collected. A Distributed Lag Nonlinear Model (DLNM) was used to evaluate the nonlinear and lagged effect of meteorological factors and air pollutants on daily RDs number. A subgroup analysis was also conducted to evaluate the effect on different sex groups and age groups. Results: A total number of 796 125 RDs visits was included during the study period. For meteorological factors, lower mean temperature and relative humidity were significantly associated with daily RDs number (peak relative risk (RR) = 1.032 (95% confidence interval (CI) = 1.011-1.053) and 1.021 (95% CI = 1.013-1.029)), while lower wind speed showed a significant association at low range (peak RR = 0.995 (95% CI = 0.992-0.999)). Temperature warming was a significant protective factor for RDs (peak RR = 0.989 (95% CI = 0.986-0.993)). For air pollutants, SO2, NO2, PM10 and PM2.5 were all significantly associated with RDs (peak RR = 1.028 (95% CI = 1.022-1.035), 1.024 (95% CI = 1.013-1.034), 1.036 (95% CI = 1.025-1.047), 1.028 (95% CI = 1.019-1.037)), and the relationship had no threshold. The estimated RR and peak lag day did not change extremely between subgroups. Conclusions: The findings provide statistical evidence for the prevention of child RDs. In addition, our findings suggested that even at low concentrations, air pollutants still have negative effects on the respiratory system.

Macrophage-intrinsic DUOX1 contributes to type 2 inflammation and mucus metaplasia during allergic airway disease.

The NADPH oxidase DUOX1 contributes to epithelial production of alarmins, including interleukin (IL)-33, in response to injurious triggers such as airborne protease allergens, and mediates development of mucus metaplasia and airway remodeling in chronic allergic airways diseases. DUOX1 is also expressed in non-epithelial lung cell types, including macrophages that play an important role in airway remodeling during chronic lung disease. We therefore conditionally deleted DUOX1 in either lung epithelial or monocyte/macrophage lineages to address its cell-specific actions in innate airway responses to acute airway challenge with house dust mite (HDM) allergen, and in chronic HDM-driven allergic airway inflammation. As expected, acute responses to airway challenge with HDM, as well as type 2 inflammation and related features of airway remodeling during chronic HDM-induced allergic inflammation, were largely driven by DUOX1 with the respiratory epithelium. However, in the context of chronic HDM-driven inflammation, DUOX1 deletion in macrophages also significantly impaired type 2 cytokine production and indices of mucus metaplasia. Further studies revealed a contribution of macrophage-intrinsic DUOX1 in macrophage recruitment upon chronic HDM challenge, as well as features of macrophage activation that impact on type 2 inflammation and remodeling.

The effects of different parity and delivery mode on wheezing disorders in the children-a retrospective cohort study in Fujian, China.

BACKGROUND: The relationship between childbirth delivery methods and the risk of wheezing in children remains controversial. Few studies have explored it under different maternal conditions. OBJECTIVE: To explore the influence of childbirth delivery method on the onset of wheezing in children of different parity. METHODS: A total of 21716 patients were included in this retrospective observational study. Multivariable logistic regression was used to analyze the relationship between childbirth delivery method and wheezing in children under 18 years of age in Fujian Province. RESULTS: Wheezing differed statistically based on the child's sex, age, season of onset, parity, jaundice history, and feeding patterns (P < 0.05). After adjusting for confounding factors, in cases of parity greater than two, the risk of wheezing in cesarean section deliveries was higher than that in vaginal deliveries (OR: 1.107; 95% CI 1.010-1.214). In girls with parity greater than two (OR: 1.179; 95% CI 1.003-1.387) and normal-weight infants with parity greater than two (OR: 1.106; 95% CI 1.003-1.220), the risk of wheezing in cesarean section deliveries was higher. The interaction term between the mode of childbirth and parity was significant in girls (P = 0.014). CONCLUSION: The method of childbirth delivery and parity are related to the risk of wheezing and may be relevant to gender and birth weight. Parity and gender have synergistic effects on wheezing.

Maternal pre-pregnancy body mass index, gestational weight gain trajectory, and risk of adverse perinatal outcomes.

OBJECTIVE: To evaluate the relationships of pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) trajectory with adverse perinatal outcomes (APOs). METHODS: A retrospective cohort study was conducted in China, and 12 855 women who had a singleton birth were included. The WHO classification categorized pre-pregnancy BMI, and five GWG trajectories were identified using the latent class growth model. RESULTS: The adjusted odds ratios for the risks of cesarean delivery, preterm birth, and large-for-gestational-age (LGA) infant were significantly higher in women with whoe were overweight or obese pre-pregnancy, but were lower in underweight (except preterm birth) than in normal weight women. Five GWG trajectories were identified: (1) retaining GWG (6.6 kg), (2) moderately slow GWG (10.5 kg), (3) moderate GWG (13.7 kg), (4) moderately fast GWG (16.3 kg), and (5) rapid GWG (19.8 kg). Compared with women in trajectory 3, the risks of cesarean delivery and LGA increase by about 35%-96% for the women in trajectory 4 or 5, whereas the women in trajectory 1 or 2 are inclined to have a higher risk of small for gestational age, but lower risk of LGA. Association of GWG trajectory with APOs varies across pre-pregnancy BMI subgroups. CONCLUSION: This study highlights the influence of inappropriate pre-pregnancy maternal weight and GWG trajectories on the risk of APOs.

Limitations of the transmitted photonic spin Hall effect through layered structure.

In this paper, we show theoretically that the spin-dependent transverse shift of the transmitted photonic spin Hall effect (SHE) through layered structure cannot exceed half of the incident beam waist. Exact conditions for obtaining the upper limit of the transmitted SHE are clarified in detail. In addition, different from the popular view in many investigations, we find that there is no positive correlation between the spin-dependent transverse displacement and the ratio between the Fresnel transmission coefficients (tp, ts). In contrast, the optimal transmission ratio is determined by the incident angle and the beam waist. Moreover, two conventional transmission structures are selected and studied in detail. The characteristics of the transverse displacements obtained are in very good agreement with our theoretical conclusions. These findings provide a deeper insight into the photonic spin Hall phenomena and offer a guide for future related research.

Oxidation-Dependent Activation of Src Kinase Mediates Epithelial IL-33 Production and Signaling during Acute Airway Allergen Challenge.

The respiratory epithelium forms the first line of defense against inhaled pathogens and acts as an important source of innate cytokine responses to environmental insults. One critical mediator of these responses is the IL-1 family cytokine IL-33, which is rapidly secreted upon acute epithelial injury as an alarmin and induces type 2 immune responses. Our recent work highlighted the importance of the NADPH oxidase dual oxidase 1 (DUOX1) in acute airway epithelial IL-33 secretion by various airborne allergens associated with H2O2 production and reduction-oxidation-dependent activation of Src kinases and epidermal growth factor receptor (EGFR) signaling. In this study, we show that IL-33 secretion in response to acute airway challenge with house dust mite (HDM) allergen critically depends on the activation of Src by a DUOX1-dependent oxidative mechanism. Intriguingly, HDM-induced epithelial IL-33 secretion was dramatically attenuated by small interfering RNA- or Ab-based approaches to block IL-33 signaling through its receptor IL1RL1 (ST2), indicating that HDM-induced IL-33 secretion includes a positive feed-forward mechanism involving ST2-dependent IL-33 signaling. Moreover, activation of type 2 cytokine responses by direct airway IL-33 administration was associated with ST2-dependent activation of DUOX1-mediated H2O2 production and reduction-oxidation-based activation of Src and EGFR and was attenuated in Duox1 -/- and Src +/- mice, indicating that IL-33-induced epithelial signaling and subsequent airway responses involve DUOX1/Src-dependent pathways. Collectively, our findings suggest an intricate relationship between DUOX1, Src, and IL-33 signaling in the activation of innate type 2 immune responses to allergens, involving DUOX1-dependent epithelial Src/EGFR activation in initial IL-33 secretion and in subsequent IL-33 signaling through ST2 activation.

Age-specific risk factors of severe pneumonia among pediatric patients hospitalized with community-acquired pneumonia.

BACKGROUND: Risk factors that predispose the development of severe community-acquired pneumonia (CAP) among pediatric CAP patients of different age ranges are yet to be identified. METHODS: We retrospectively analyzed pediatric in-patients (< 6 years old) diagnosed with CAP in our hospital. We subdivided patients into four age groups (< 6 months, 6 months-1 year, 1-2 years, and 2-6 years). Their medical records, including demographic information, clinical features, laboratory findings, and chest radiographic reports, were reviewed and collected for further analysis. Univariate logistic regression analysis and stepwise regression analysis were applied to identify risk factors associated with severe CAP and ICU admission for overall patients and age-stratified subgroups. RESULTS: A total of 20,174 cases were initially included. Among them, 3309 (16.40%) cases were identified as severe CAP, and 2824 (14.00%) cases required ICU admission. Potential risk factors for severe CAP and ICU admission identified by univariate analysis included younger age, rural residency, premature birth, low birth weight (LBW), formula feeding, congenital heart disease (CHD), history of pneumonia or neonatal jaundice, patients with other health issues, certain symptoms (manifesting wheezing, dyspnea, cyanosis, but have no cough or fever), abnormal laboratory findings (abnormal levels of white blood cells, albumin, and C-reactive protein and RSV infection), and chest X-ray (odds ratio [OR] > 1 for all). CHD, low albumin, proteinuria, abnormal chest x-ray were independent risks factors across different age groups, whereas birth or feeding history, history of pneumonia, cyanosis or dyspnea on admission, and RSV infection were independent risk factors for only younger kids (< 1 year), and wheezing was an independent risk factor only for older children (2-5 years old). CONCLUSIONS: Risk factors predicting disease severity among children hospitalized with CAP vary with age. Risk factor stratification of pediatric CAP based on age-specific risk factors can better guide clinical practice. TRIAL REGISTRATION: This study has been registered in China, with the registration number being ChiCTR2000033019 .

Risk factors associated with wheezing in severe pediatric community-acquired pneumonia: a retrospective study.

BACKGROUND: Wheezing is a common clinical manifestation in children with pneumonia. However, the risk factors associated with the development of wheezing pneumonia and its clinical features are not fully characterized, especially in children with severe pneumonia. METHODS: We retrospectively recruited 1434 pediatric patients diagnosed with severe pneumonia between April 2012 and September 2019 in Fujian Maternity and Child Health Hospital. The medical records regarding demographic information, clinical manifestations, radiographic/laboratory findings, and complications were collected. Based on the presence or absence of wheezing symptoms and signs, subjects were divided into wheezing cohort (n=684) and non-wheezing cohort (n=750), and their clinical data were compared. Multivariate cox regression analysis was performed to identify independent risk factors of wheezing. RESULTS: Demographic features including gender, weigh, onset season, birth weight, full-term birth or not, history of pneumonia were significantly associated with the occurrence of wheezing in severe CAP (P<0.05). Specifically, male gender, onset seasons in autumn/winter, and absence of a history of pneumonia were identified as independent risk factors of wheezing in multivariate analysis (P<0.05). As for clinical features, wheezing cohort differed from the non-wheezing one in terms of clinical manifestation (higher incidence of cough and breathless, but lower incidence of fever), laboratory finding (higher levels of red blood cells, hemoglobin, and albumin and lower levels of total or indirect bilirubin and creatine), pathogen detection (higher incidence of respiratory syncytial viral infection), and clinical complications (lesser risk of sepsis and hydrothorax) (P<0.05). CONCLUSIONS: Severe CAP with wheezing is a special clinical entity of severe pneumonia in children, which has specific risk factors and differ from non-wheezing pneumonia in terms of clinical features and etiologic pathogens.

Redox regulation of tyrosine kinase signalling: more than meets the eye.

Protein kinases are essential mediators of cellular signal transduction and are often dysregulated in disease. Among these, protein tyrosine kinases (PTKs) have received specific interest due to their common roles in various diseases including cancer, and emerging observations indicating that PTK signalling pathways are susceptible to regulation by reactive oxygen species (ROS), which are also frequently implicated in disease pathology. While it is well recognized that ROS can impact on tyrosine kinase signalling by inhibiting tyrosine phosphatases, more recent studies highlight additional modes of redox-based regulation of tyrosine kinase signalling by direct redox modification of non-catalytic cysteines within tyrosine kinases or other protein components of this signalling pathway. In this review, we will present recent advancements with respect to redox-based mechanisms in regulating PTK signalling, with a specific focus on recent studies demonstrating direct redox regulation of Src-family kinases and epidermal growth factor receptor kinases. Importantly, redox-based modulation of tyrosine kinases may be relevant for many other kinases and has implications for current approaches to develop pharmacological inhibitors for these proteins.

SIRT5 stabilizes mitochondrial glutaminase and supports breast cancer tumorigenesis.

The mitochondrial enzyme glutaminase (GLS) is frequently up-regulated during tumorigenesis and is being evaluated as a target for cancer therapy. GLS catalyzes the hydrolysis of glutamine to glutamate, which then supplies diverse metabolic pathways with carbon and/or nitrogen. Here, we report that SIRT5, a mitochondrial NAD+-dependent lysine deacylase, plays a key role in stabilizing GLS. In transformed cells, SIRT5 regulates glutamine metabolism by desuccinylating GLS and thereby protecting it from ubiquitin-mediated degradation. Moreover, we show that SIRT5 is up-regulated during cellular transformation and supports proliferation and tumorigenesis. Elevated SIRT5 expression in human breast tumors correlates with poor patient prognosis. These findings reveal a mechanism for increasing GLS expression in cancer cells and establish a role for SIRT5 in metabolic reprogramming and mammary tumorigenesis.

Liver-Type Glutaminase GLS2 Is a Druggable Metabolic Node in Luminal-Subtype Breast Cancer.

Efforts to target glutamine metabolism for cancer therapy have focused on the glutaminase isozyme GLS. The importance of the other isozyme, GLS2, in cancer has remained unclear, and it has been described as a tumor suppressor in some contexts. Here, we report that GLS2 is upregulated and essential in luminal-subtype breast tumors, which account for >70% of breast cancer incidence. We show that GLS2 expression is elevated by GATA3 in luminal-subtype cells but suppressed by promoter methylation in basal-subtype cells. Although luminal breast cancers resist GLS-selective inhibitors, we find that they can be targeted with a dual-GLS/GLS2 inhibitor. These results establish a critical role for GLS2 in mammary tumorigenesis and advance our understanding of how to target glutamine metabolism in cancer.

Dysregulated Redox Regulation Contributes to Nuclear EGFR Localization and Pathogenicity in Lung Cancer.

Lung cancers are frequently characterized by inappropriate activation of epidermal growth factor receptor (EGFR)-dependent signaling and epigenetic silencing of the NADPH oxidase (NOX) enzyme DUOX1, both potentially contributing to worse prognosis. Based on previous findings linking DUOX1 with redox-dependent EGFR activation, the present studies were designed to evaluate whether DUOX1 silencing in lung cancers may be responsible for altered EGFR regulation. In contrast to normal epithelial cells, EGF stimulation of lung cancer cell lines that lack DUOX1 promotes EGF-induced EGFR internalization and nuclear localization, associated with induction of EGFR-regulated genes and related tumorigenic outcomes. Each of these outcomes could be reversed by overexpression of DUOX1 or enhanced by shRNA-dependent DUOX1 silencing. EGF-induced nuclear EGFR localization in DUOX1-deficient lung cancer cells was associated with altered dynamics of cysteine oxidation of EGFR, and an overall reduction of EGFR cysteines. These various outcomes could also be attenuated by silencing of glutathione S-transferase P1 (GSTP1), a mediator of metabolic alterations and drug resistance in various cancers, and a regulator of cysteine oxidation. Collectively, our findings indicate DUOX1 deficiency in lung cancers promotes dysregulated EGFR signaling and enhanced GSTP1-mediated turnover of EGFR cysteine oxidation, which result in enhanced nuclear EGFR localization and tumorigenic properties.

An Essential Role for Cdc42 in the Functioning of the Adult Mammary Gland.

The Rho family small GTPase Cdc42 has been implicated in a wide range of cellular functions including the establishment of cell polarity and the remodeling of the actin cytoskeletal architecture, resulting in the tight regulation of cell growth and survival during developmental processes. The complete knock-out of Cdc42 in the mouse is embryonic-lethal, and its targeted deletion in various tissues has been shown to disrupt tissue homeostasis. Thus far, in most studies, the targeted deletion of Cdc42 occurred during embryogenesis. Here, we have used a conditional gene deletion strategy in mice to probe the specific role of Cdc42 during adult mammary gland function. Cdc42 conditional-knock-out females were unable to adequately nourish their pups, due to a disorganized epithelial compartment within their mammary glands. A closer examination showed that their mammary epithelial cells were not able to maintain functional alveolar lumens, due to an inability to establish normal apical/basal epithelial polarity, as well as proper cell-cell contacts. Loss of these essential epithelial characteristics led to a premature sloughing off of the Cdc42-null epithelial cells. Overall our findings demonstrate that Cdc42 plays essential roles in mammary gland function post pregnancy, where it helps to establish proper epithelial cell polarity and tissue homeostasis during lactation.

Identification of mTORC2 as a necessary component of HRG/ErbB2-dependent cellular transformation.

UNLABELLED: Overexpression of the receptor tyrosine kinase HER2/ErbB2 (ERBB2) has been linked to a poor prognosis for patients with breast cancer; thus, its activity is a central target for cancer therapy. Likewise, overexpression of heregulin (HRG/NRG1), a growth factor responsible for ErbB2 activation, has also been shown to be a driver of breast cancer progression. Although ErbB2 inhibitors offer a major advancement in the treatment of ErbB2-dependent breast cancers, patients are highly susceptible to developing clinical resistance to these drugs. Therefore, a detailed understanding of the molecular mechanism that underlies HRG/ErbB2-induced tumorigenesis is essential for the development of effective therapeutic strategies for this subset of patients with breast cancer. Here, it was demonstrated that HRG promoted anchorage-independent breast cancer cell growth more potently than EGF, and that the HRG-dependent activation of phosphoinositide 3-kinase and mTORC1 are necessary events for cell transformation. Functional evaluation of two distinct mTOR (MTOR) inhibitors, rapamycin and INK-128, on HRG-dependent signaling activities, uncovered a necessary role for mTORC2 in the regulation of the AKT/TSC2/mTORC1 axis by affecting the phosphorylation of AKT at the PDK1(PDPK1)-dependent site (T308) as well as at the mTORC2-dependent site (S473). The elimination of Rictor (RICTOR), a critical component of mTORC2, is detrimental to both the activation of mTORC1 and HRG-mediated cellular transformation. Similar results were obtained in multiple breast cancer model systems, highlighting an important role for mTORC2 in HRG/ErbB2-dependent breast cancer. IMPLICATIONS: These findings suggest the potential benefits of targeting mTORC2 in HRG/ErbB2-induced breast cancer.