Exosomal Wnt-induced dedifferentiation of colorectal cancer cells contributes to chemotherapy resistance

Cancer stem cells (CSCs) are inherently resistant to chemotherapy, and CSCs in chemotherapy-failed recurrent tumors are enriched; however, the cellular origin of chemotherapy-induced CSC enrichment remains unclear. Communication with stromal fibroblasts may induce cancer cell dedifferentiation into CSCs through secreted factors. We recently demonstrated that fibroblast-derived exosomes promote chemoresistance in colorectal cancer (CRC). Here, we report that fibroblasts confer CRC chemoresistance via exosome-induced reprogramming (dedifferentiation) of bulk CRC cells to phenotypic and functional CSCs. At the molecular level, we provided evidence that the major reprogramming regulators in fibroblast-exosomes are Wnts. Exosomal Wnts were found to increase Wnt activity and drug resistance in differentiated CRC cells, and inhibiting Wnt release diminished this effect in vitro and in vivo. Together, our results indicate that exosomal Wnts derived from fibroblasts could induce the dedifferentiation of cancer cells to promote chemoresistance in CRC, and suggest that interfering with exosomal Wnt signaling may help to improve chemosensitivity and the therapeutic window.

Plant growth promotion and suppression of bacterial leaf blight in rice by Paenibacillus polymyxa Sx3

The effects and mechanisms of Paenibacillus polymyxa Sx3 on growth promotion and the suppression of bacterial leaf blight in rice were evaluated in this study. The results from a plate assay indicated that Sx3 inhibited the growth of 20 strains of Xanthomonas oryzae pv. oryzae (Xoo). Rice seedling experiments indicated that Sx3 promoted plant growth and suppressed bacterial leaf blight. In addition, bacteriological tests showed that Sx3 was able to fix nitrogen, solubilize phosphate and produce indole acetic acid, indicating that various mechanisms may be involved in the growth promotion by Sx3. The culture filtrate of P. polymyxa Sx3 reduced bacterial growth, biofilm formation and disrupted the cell morphology of Xoo strain GZ 0005, as indicated by the transmission and scanning electron microscopic observations. In addition, MALDI-TOF MS analysis revealed that Sx3 could biosynthesize two types of secondary metabolites fusaricidins and polymyxin P. In summary, this study clearly indicated that P. polymyxa Sx3 has strong in vitro and in vivo antagonistic activity against Xoo, which may be at least partially attributed to its production of secondary metabolites. SIGNIFICANCE AND IMPACT OF THE STUDY: Antagonistic bacteria can grow well in their originating environment. However, it is unclear whether antagonistic bacteria were able to survive in different ecological environments. This study revealed that Paenibacillus polymyxa Sx3 isolated from rhizosphere soil of cotton significantly promoted the plant growth and suppressed bacterial leaf blight in rice. Therefore, it could be inferred that P. polymyxa Sx3 has the potential to be used as biocontrol agents in plants grown in different ecological environments.

Theoretical investigation on the optical and EPR spectra for Cu2+ -doped ZnO-CdS nanocomposites

The three optical absorption bands and EPR parameters of the [CuO6 ]10- center in the ZnO-CdS composite nanopowders are theoretically studied from the perturbation formulas based on the cluster approach. In the formulas, the contributions to EPR parameters arising from the ligand orbital and spin-orbit coupling interactions via covalence effect are considered. For the studied [CuO6 ]10- cluster, the Cu-O bond lengths are suggested to show a relative elongation ratio ρ (≈ 4.1%) along the z-axis due to Jahn-Teller effect. The defect models suggested in this work are different from the previous assumption that the impurity Cu2+ can replace the host Zn2+ site when it enters the lattices of the ΖnO and ΖnS nanocrystals, forming the tetrahedral [CuΧ4 ]6- clusters (Χ = O, S). The validity of the proposed model is discussed. The differences between the present calculations and the previous ones for the interstitial Cu2+ center in ZnO nanocrystals are analyzed in view of the dissimilar impurity behaviors due to the new composition CdS and distinct preparation conditions.

Electrical Detection of Charge-to-spin and Spin-to-Charge Conversion in a Topological Insulator Bi2Te3 Using BN/Al2O3 Hybrid Tunnel Barrier

One of the most striking properties of three-dimensional topological insulators (TIs) is spin-momentum locking, where the spin is locked at right angles to momentum and hence an unpolarized charge current creates a net spin polarization. Alternatively, if a net spin is injected into the TI surface state system, it is distinctively associated with a unique carrier momentum and hence should generate a charge accumulation, as in the so-called inverse Edelstein effect. Here using a Fe/Al₂O₃/BN tunnel barrier, we demonstrate both effects in a single device in Bi₂Te₃: the electrical detection of the spin accumulation generated by an unpolarized current flowing through the surface states, and that of the charge accumulation generated by spins injected into the surface state system. This work is the first to utilize BN as part of a hybrid tunnel barrier on TI, where we observed a high spin polarization of 93% for the TI surfaces states. The reverse spin-to-charge measurement is an independent confirmation that spin and momentum are locked in the surface states of TI, and offers additional avenues for spin manipulation. It further demonstrates the robustness and versatility of electrical access to the spin system within TI surface states, an important step towards its utilization in TI-based spintronics devices.

Sortilin: a new player in dementia and Alzheimer-type neuropathology

Age-related dementias are now a major mortality factor among most human populations in the world, with Alzheimer's disease (AD) being the leading dementia-causing neurodegenerative disease. The pathogenic mechanism underlying dementia disorders, and AD in particular, remained largely unknown. Efforts to develop drugs targeting the disease's hallmark lesions, such as amyloid plaque and tangle pathologies, have been unsuccessful so far. The vacuolar protein sorting 10p (Vps10p) family plays a critical role in membrane signal transduction and protein sorting and trafficking between intracellular compartments. Data emerging during the past few years point to an involvement of this family in the development of AD. Specifically, the Vps10p member sortilin has been shown to participate in amyloid plaque formation, tau phosphorylation, abnormal protein sorting and apoptosis. In this minireview, we update some latest findings from animal experiments and human brain studies suggesting that abnormal sortilin expression is associated with AD-type neuropathology, warranting further research that might lead to novel targets for the development of AD therapies.

Engineering the spin polarization of one-dimensional electrons

We present results of magneto-focusing on the controlled monitoring of spin polarization within a one-dimensional (1D) channel, and its subsequent effect on modulating the spin-orbit interaction (SOI) in a 2D GaAs electron gas. We demonstrate that electrons within a 1D channel can be partially spin polarized as the effective length of the 1D channel is varied in agreement with the theoretical prediction. Such polarized 1D electrons when injected into a 2D region result in a split in the odd-focusing peaks, whereas the even peaks remain unaffected (single peak). On the other hand, the unpolarized electrons do not affect the focusing spectrum and the odd and even peaks remain as single peaks, respectively. The split in odd-focusing peaks is evidence of direct measurement of spin polarization within a 1D channel, where each sub-peak represents the population of a particular spin state. Confirmation of the spin splitting is determined by a selective modulation of the focusing peaks due to the Zeeman energy in the presence of an in-plane magnetic field. We suggest that the SOI in the 2D regime is enhanced by a stream of polarized 1D electrons. The spatial control of spin states of injected 1D electrons and the possibility of tuning the SOI may open up a new regime of spin-engineering with application in future quantum information schemes.

Neutrophil Gelatinase-Associated Lipocalin Attenuates Ischemia/Reperfusion Injury in an In Vitro Model via Autophagy Activation

Background

The aim of this study was to investigate the protective effects of neutrophil gelatinase-associated lipocalin (NGAL) on hypoxia/reoxygenation (H/R) induced acute kidney injury (AKI) in vitro.

Material/Methods

We used NRK-52E cells and H/R treatments to mimic ischemia/reperfusion injury (IRI) in vitro. Experimental groups were: the control group, the H/R group, the 3-methyladenine (3-MA)+H/R group, the NGAL (0.25, 0.5, and 1 ug/mL)+H/R group, and the NGAL (0.25, 0.5, 1 ug/mL)+3-MA+H/R group. After 24 hours of culture, cell proliferation was analyzed by CCK-8 assay. Expression of LC3-II was detected by immunoblot assay. Autophagy was detected by electron microscopy.

Results

The expression of LC3-II was increased in the H/R group compared with normoxic condition (p<0.05) and proliferation also improved. Autophagy was significantly inhibited by 3-MA, with downregulated of LC3-II, followed by decreased cell viability (p<0.05). We further detected the effect of different doses of NGAL in H/R induced injury, and found that low doses of NGAL alone slightly increased LC3-II protein accumulation, and autophagy was further induced with higher dose of NGAL treatment. Meanwhile, cell viability assays showed induced cell survival. We found that in the NGAL+3-MA group, cell viability assays revealed reduced cell damage, followed concomitantly with depressed autophagy. The formulation of autophagosomes were correlated with LC3-II protein expression in each group.

Conclusions

Autophagy plays a renoprotective role in H/R injury, as well in AKI. NGAL might be related to attenuated tubular epithelial cell damage via adjusting autophagy.

Combined skin and muscle vaccination differentially impact the quality of effector T cell functions: the CUTHIVAC-001 randomized trial

Targeting of different tissues via transcutaneous (TC), intradermal (ID) and intramuscular (IM) injection has the potential to tailor the immune response to DNA vaccination. In this Phase I randomised controlled clinical trial in HIV-1 negative volunteers we investigate whether the site and mode of DNA vaccination influences the quality of the cellular immune responses. We adopted a strategy of concurrent immunization combining IM injection with either ID or TC administration. As a third arm we assessed the response to IM injection administered with electroporation (EP). The DNA plasmid encoded a MultiHIV B clade fusion protein designed to induce cellular immunity. The vaccine and regimens were well tolerated. We observed differential shaping of vaccine induced virus-specific CD4 + and CD8 + cell-mediated immune responses. DNA given by IM + EP promoted strong IFN-γ responses and potent viral inhibition. ID + IM without EP resulted in a similar pattern of response but of lower magnitude. By contrast TC + IM (without EP) shifted responses towards a more Th-17 dominated phenotype, associated with mucosal and epidermal protection. Whilst preliminary, these results offer new perspectives for differential shaping of desired cellular immunity required to fight the wide range of complex and diverse infectious diseases and cancers.

Atf3 deficiency promotes genome instability and spontaneous tumorigenesis in mice

Mice lacking genes involving in the DNA damage response (DDR) are often tumor prone owing to genome instability caused by oncogenic challenges. Previous studies demonstrate that activating transcription factor 3 (ATF3), a common stress sensor, can activate the tumor suppressor p53 and regulate expression of p53 target genes upon DNA damage. However, whether ATF3 contributes to the maintenance of genome stability and tumor suppression remains unknown. Here we report that Atf3-deficient (Atf3^-/-) mice developed spontaneous tumors, and died significantly earlier than wild-type (Atf3^+/+) mice. Consistent with these results, Atf3^-/- mouse embryonic fibroblasts (MEFs) had more aberrant chromosomes and micronuclei, and were genetically unstable. Whereas we demonstrated that ATF3 activated p53 and promoted its pro-apoptotic activity in mouse thymi and small intestines, the chromosomal instability caused by Atf3 deficiency was largely dependent on the regulation of p53 by ATF3. Interestingly, loss of Atf3 also promoted spontaneous tumorigenesis in Trp53^+/- mice, but did not affect tumor formation in Trp53^-/- mice. Our results thus provide the first genetic evidence linking ATF3 to the suppression of the early development of cancer, and underscore the importance of ATF3 in the maintenance of genome integrity.

[Clinical efficacy of acute intraoperative encephalocele prevention strategy for severe traumatic brain injury]

Objective: To explore the clinical efficacy of prevention strategy for acute intraoperative encephalocele of patients with severe traumatic brain injury (sTBI). Methods: A total of 173 patients with sTBI, who treated in Emergency Neurosurgery Department of Shandong University Qilu Hospital from January, 2011 to September, 2015 were collected and divided into research group and control group, according to their therapeutic strategy.The clinical data during hospitalization and prognosis 1 year after injury was analyzed retrospectively to clarify the effect of acute encephalocele prevention strategy. Results: There were no statistically significant differences in sex, age, preoperative Glasgow coma scale score and imaging type of lesion between patients from the two groups.The highest intraoperative intracranial pressure in the research group and control group were (35.71±4.13) mmHg and(34.85±3.81) mmHg, respectively.The acute encephalocele incidence of the research group (7 cases, 6.5%) was significantly lower than that of the control group (13 cases, 19.7%) (P<0.01). Subgroup analysis showed that the incidence of acute encephalocele in patients with only unilateral lesions was low (1.3%), while higher (19.4%) in patients with both unilateral lesions and other secondary lesions or diffuse brain swelling.The prognosis of the patients was evaluated by Glasgow Outcome Scale according to the follow-up 1 year after injury, and it was suggested that the percentage of patients with good outcome in the research group (62 cases, 57.9%) was remarkably higher than that in the control group (26 cases, 39.4%) (P=0.018). Conclusions: For sTBI patients with high risk of acute encephalocele, prevention strategy was found to be able to retard the progression of delayed hematoma and diffuse brain swelling, prevent the acute encephalocele during operation, and then significantly improve the prognosis.

Butyrate and retinoic acid imprint mucosal-like dendritic cell development synergistically from bone marrow cells

Accumulating data show that the phenotypes and functions of distinctive mucosal dendritic cells (DCs) in the gut are regulated by retinoic acid (RA). Unfortunately, the exact role of butyrate in RA-mediated mucosal DC differentiation has not been elucidated thoroughly to date. Mucosal-like dendritic cell differentiation was completed in vitro by culturing bone marrow cells with growth factors [granulocyte-macrophage colony-stimulating factor (GM-CSF/interleukin (IL)-4], RA and/or butyrate. The phenotypes, cytokine secretion, immune functions and levels of retinal dehydrogenase of different DCs were detected using quantitative polymerase chain reaction (qPCR), enzyme-linked immunosorbent assay (ELISA) and flow cytometry, respectively. The results showed that RA-induced DCs (RA-DCs) showed mucosal DC properties, including expression of CD103 and gut homing receptor α₄ β₇ , low proinflammatory cytokine secretion and low priming capability to antigen-specific CD4⁺ T cells. Butyrate-treated RA-DCs (Bu-RA-DCs) decreased CD11c, but increased CD103 and α₄ β₇ expression. Moreover, the CD4⁺ T priming capability and the levels of retinal dehydrogenase of RA-DCs were suppressed significantly by butyrate. Thus, butyrate and retinoic acid have different but synergistic regulatory functions on mucosal DC differentiation, indicating that immune homeostasis in the gut depends largely upon RA and butyrate to imprint different mucosal DC subsets, both individually and collectively.

Surfactant reduced the mortality of neonates with birth weight ⩾1500 g and hypoxemic respiratory failure: a survey from an emerging NICU network

OBJECTIVE

We evaluated the efficacy of surfactant therapy and assisted ventilation on morbidity and mortality of neonates with birth weight (BW) ⩾1500 g and hypoxemic respiratory failure (HRF).

STUDY DESIGN

We retrospectively analyzed 5650 patients with BW ⩾1500 g for incidence, management and outcome of HRF, defined as acute hypoxemia requiring mechanical ventilation and/or nasal continuous positive airway pressure ⩾24 h. The patients were allocated into groups of moderate preterm (1735, 30.7%), late preterm (1431, 25.4%), early term (ETM, 986, 17.5%), full term (1390, 24.6%) and post term (79, 1.4%), with gestational age ⩽33, 34 to 36, 37 to 38, 39 to 41 and ⩾42 weeks, respectively.

RESULTS

In the five groups, 66.9, 42, 21.6, 12.8 and 5.1% had respiratory distress syndrome (RDS). For pneumonia/sepsis and meconium aspiration syndrome (MAS), the proportion was 13.8%, 25.4%, 38.0%, 52.5% and 76.0%, respectively. Surfactant was given to 21.9% (n=1238) of HRF and 51.2% (n=1108) of RDS. Survival rates of RDS were 82.2%, 87.8%, 84.5%, 77.1% and 75.0%, respectively (numbers needed to treat was 8 to 11 for surfactant benefit). Overall mortality rate of HRF was 21%, or 17.9%, 14.7%, 25.6%, 28.9% and 39.2%, respectively. Mortalities of MAS and pneumonia/sepsis were 29.4 and 27.6%. Relative risk of death was associated with initial disease severity, female gender, mechanical ventilation and congenital anomalies by multivariate logistic regression analysis.

CONCLUSION

Surfactant was effective for infants with RDS and BW ⩾1500 g, and different incidences and outcome of HRF among GA groups reflected standard of perinatal and respiratory care in emerging neonatal intensive care unit network.

[Laparoscopic reoperation for recurred antireflux surgery of gastroesophageal reflux disease]

OBJECTIVE

To investigate the safety and effectiveness of laparoscopic reoperation for patients with gastroesophageal reflux disease (GERD) recurred form previous anti-reflux surgery.

METHODS

Totally 19 patients received laparoscopic reoperation for symptomatic and anatomic recurred GERD in Department of Gastroesophageal Reflux Disease, Rocket Force General Hospital from January 2008 to September 2015 were retrospectively analyzed. There were 12 male and 7 female patients. The average reoperation age was (48±14) years, the average duration of reoperation from original ones was (43±38) months. The patients underwent preoperative barium, endoscopy, manometry and 24-hour pH studies. Laparoscopic hiatal hernia repair plus fundoplication was carried out for reoperation. Gastroesophageal reflux related symptoms (reflux, heartburn, chest pain, chough, wheezing, chest tightness and globus sensation) before and after surgery were compared by a questionnaire. The patients' medication consumption, complications and satisfaction of the reoperation were investigated as well. The repeated measures analysis of variance was used for statistical comparison of data preoperatively and postoperatively.

RESULTS

No major complication and death occurred. Six cases (32%) had complications such as diarrhea, increased passing wind, flatulence, dysphagia and abdominal pain. The GERD related symptom score of reflux, heartburn, chest pain, chough, wheezing, chest tightness and globus sensation all significantly decreased (F: 25.0 to 56.7; P: 0.000 to 0.001) after the reoperation, with 68% good outcome of all the patients. After a follow-up of (33±22) months after reoperation, 1 case had partial recurrence at the 3(rd) month after reoperation. For all the patients, 12 cases felt very satisfied or satisfied with the reoperation.

CONCLUSION

Laparoscopic reoperation is generally effective with acceptable morbidity rates for patients with esophageal and extraesophageal symptoms recurred form previous hiatal repair and (or) fundoplication.

Increased glycogen synthase kinase-3β and hexose-6-phosphate dehydrogenase expression in adipose tissue may contribute to glucocorticoid-induced mouse visceral adiposity

BACKGROUND

Increased adiposity in visceral depots is a crucial feature associated with glucocorticoid (GC) excess. The action of GCs in target tissue is regulated by GC receptor (GR) and 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1) coupled with hexose-6-phosphate dehydrogenase (H6pdh). Glycogen synthase kinase-3β (GSK3β) is known to be a crucial mediator of ligand-dependent gene transcription. We hypothesized that the major effects of corticosteroids on adipose fat accumulation are in part medicated by changes in GSK3β and H6pdh.

METHODS

We characterized the alterations of GSK3β and GC metabolic enzymes, and determined the impact of GR antagonist mifepristone on obesity-related genes and the expression of H6pdh and 11ß-HSD1 in adipose tissue of mice exposed to excess GC as well as in in vitro studies using 3T3-L1 adipocytes treated with GCs.

RESULTS

Corticosterone (CORT) exposure increased abdominal fat mass and induced expression of lipid synthase ACC and ACL with activation of GSK3β phosphorylation in abdominal adipose tissue of C57BL/6J mice. Increased pSer⁹ GSK3β was correlated with induction of H6pdh and 11ß-HSD1. Additionally, mifepristone treatment reversed the production of H6pdh and attenuated CORT-mediated production of 11ß-HSD1 and lipogenic gene expression with reduction of pSer⁹ GSK3β, thereby leading to improvement of phenotype of adiposity within adipose tissue in mice treated with excess GCs. Suppression of pSer⁹ GSK3β by mifepristone was accompanied by activation of pThr³⁰⁸ Akt and blockade of CORT-induced adipogenic transcriptor C/EBPα and PPARγ. In addition, mifepristone also attenuated CORT-mediated activation of IRE1α/XBP1. Additionally, reduction of H6pdh by shRNA showed comparable effects to mifepristone on attenuating CORT-induced expression of GC metabolic enzymes and improved lipid accumulation in vitro in 3T3-L1 adipocytes.

CONCLUSION

These findings suggest that elevated adipose GSK3β and H6pdh expression contribute to 11ß-HSD1 mediating hypercortisolism associated with visceral adiposity.

Artesunate protects pancreatic beta cells against cytokine-induced damage via SIRT1 inhibiting NF-κB activation

AIM

Artesunate (ART) has been known as the most effective and safe reagents to treat malaria for many years. In this study, we explored whether ART could protect pancreatic beta-cell against cytokine-induced damage.

MATERIALS AND METHODS

The production of nitrite (NO) was detected with the Griess Assay Kit. SIRT1 and inducible nitric oxide synthase (iNOS) expression were determined with Western blot. The transcriptional activity of NF-κB was evaluated by luciferase reporter assay. The expression of Sirt1 was silenced by RNA interference. Glucose-stimulated insulin secretion (GSIS) and potassium-stimulated insulin secretion (KSIS) assays were performed to measure the effect of ART on pancreatic beta-cells' function. The effect of ART on beta-cells apoptosis was evaluated by using Hochest/PI staining and TUNEL assay.

RESULTS

ART enhanced GSIS (KSIS) and reduced apoptosis of pancreatic beta-cells induced by IL-1β. Further study showed that ART inhibited IL-1β-induced increase of NF-κB activity, iNOS expression, and NO production. Moreover, ART up-regulated SIRT1 expression in INS-1 cells and islets exposed to IL-1β. Inhibition of SIRT1 expression could partially abolished the inhibitory effect of ART on NF-κB activity in IL-1β-treated beta-cells. More importantly, the protective effect of ART on cytokine-induced damage was reversed by silencing SIRT1 expression.

CONCLUSIONS

ART can elicit a protective effect on beta-cells exposed to IL-1β by stimulating SIRT1 expression, which resulted in the decrease of NF-κB activity, iNOS expression, and NO production. Hence, ART might be an effective drug for diabetes.

Loss of ATF3 promotes hormone-induced prostate carcinogenesis and the emergence of CK5(+)CK8(+) epithelial cells

Steroid sex hormones can induce prostate carcinogenesis, and are thought to contribute to the development of prostate cancer during aging. However, the mechanism for hormone-induced prostate carcinogenesis remains elusive. Here we report that activating transcription factor 3 (ATF3) – a broad stress sensor – suppressed hormone-induced prostate carcinogenesis in mice. While implantation of testosterone and estradiol (T+E₂) pellets for 2 months in wild-type mice rarely induced prostatic intraepithelial neoplasia (PIN) in dorsal prostates (1 out of 8 mice), loss of ATF3 led to the appearance of not only PIN but also invasive lesions in almost all examined animals. The enhanced carcinogenic effects of hormones on ATF3-deficient prostates did not appear to be caused by a change in estrogen signaling, but were more likely a consequence of elevated androgen signaling that stimulated differentiation of prostatic basal cells into transformation-preferable luminal cells. Indeed, we found that hormone-induced lesions in ATF3-knockout mice often contained cells with both basal and luminal characteristics, such as p63⁺ cells (a basal cell marker) showing luminal-like morphology, or cells double-stained with basal (CK5⁺) and luminal (CK8⁺) markers. Consistent with these findings, low ATF3 expression was found to be a poor prognostic marker for prostate cancer in a cohort of 245 patients. Our results thus support that ATF3 is a tumor suppressor in prostate cancer.

RNF126 promotes homologous recombination via regulation of E2F1-mediated BRCA1 expression

RNF126 is an E3 ubiquitin ligase. The deletion of RNF126 gene was observed in a wide range of human cancers and is correlated with improved disease-free and overall survival. These data highlights the clinical relevance of RNF126 in tumorigenesis and cancer therapy. However, the specific functions of RNF126 remain largely unknown. Homologous recombination (HR)-mediated DNA double-strand break repair is important for tumor suppression and cancer therapy resistance. Here, we demonstrate that RNF126 facilitates HR by promoting the expression of BRCA1, in a manner independent of its E3 ligase activity but depending on E2F1, a well-known transcription factor of BRCA1 promoter. In support of this result, RNF126 promotes transactivation of BRCA1 promoter by directly binding to E2F1. Most importantly, an RNF126 mutant lacking 11 amino acids that is responsible for the interaction with E2F1 has a dominant-negative effect on BRCA1 expression and HR by suppressing E2F1-mediated transactivation of BRCA1 promoter and blocking the enrichment of E2F1 on BRCA1 promoter. Lastly, RNF126 depletion leads to the increased sensitivity to ionizing radiation (IR) and poly (ADP-ribose) polymerase (PARP) inhibition. Collectively, our results suggest a novel role of RNF126 in promoting HR-mediated repair through positive regulation on BRCA1 expression by direct interaction with E2F1. This study not only offers novel insights into our current understanding of the biological functions of RNF126 but also provides a potential therapeutic target for cancer treatment.

[IGHMBP2 overexpression promotes cell migration and invasion in esophageal squamous carcinoma]

Immunoglobulin mu binding protein 2 (IGHMBP2) is located in 11q13.2, which is frequently amplified in esophageal squamous cell carcinoma (ESCC). IGHMBP2 encodes a helicase involved in DNA replication and repair. IGHMBP2 protein also regulates gene transcription. The present study aims to explore the amplification of IGHMBP2 and its potential role in ESCC. A further analysis of our previously reported array-CGH data showed that IGHMBP2 was amplified in 28.9% of primary ESCC tumors. Fluorescence in situ hybridization (FISH) and Western blot showed that IGHMBP2 was amplified and overexpressed in KYSE30, KYSE180, KYSE510 and KYSE150 esophageal cancer cell lines. Transwell assays demonstrated that knockdown of IGHMBP2 in KYSE30 and KYSE150 inhibited cell invasion and migration, and increased the expression levels of E-cadherin. When rescue plasmids expressing IGHMBP2 were introduced, the abilities of cell invasion and migration were restored. These data suggest that IGHMBP2 overexpression may promote invasion and migration of ESCC cells through down-regulation of E-cadherin.

International Mycoplasma pneumoniae typing study: interpretation of M. pneumoniae multilocus variable-number tandem-repeat analysis

Typing of Mycoplasma pneumoniae by multiple-locus variable-number tandem repeat analysis (MLVA) is increasingly in use. However, no specific internationally agreed guidance is available. Thirty M. pneumoniae DNA samples including serial dilutions of a type strain were sent to six international laboratories to perform MLVA and results were compared. Good correlation was observed, indicating that this methodology can be robustly performed in multiple sites. However, differences due to interpretation of fragment size, repeat sequence identification and repeat numbering led to inconsistency in the final profiles assigned by laboratories. We propose guidelines for interpreting M. pneumoniae MLVA typing and assigning the number of repeats.

Dysregulated choline metabolism in T-cell lymphoma: role of choline kinase-α and therapeutic targeting

Cancer cells have distinct metabolomic profile. Metabolic enzymes regulate key oncogenic signaling pathways and have an essential role on tumor progression. Here, serum metabolomic analysis was performed in 45 patients with T-cell lymphoma (TCL) and 50 healthy volunteers. The results showed that dysregulation of choline metabolism occurred in TCL and was related to tumor cell overexpression of choline kinase-α (Chokα). In T-lymphoma cells, pharmacological and molecular silencing of Chokα significantly decreased Ras-GTP activity, AKT and ERK phosphorylation and MYC oncoprotein expression, leading to restoration of choline metabolites and induction of tumor cell apoptosis/necropotosis. In a T-lymphoma xenograft murine model, Chokα inhibitor CK37 remarkably retarded tumor growth, suppressed Ras-AKT/ERK signaling, increased lysophosphatidylcholine levels and induced in situ cell apoptosis/necropotosis. Collectively, as a regulatory gene of aberrant choline metabolism, Chokα possessed oncogenic activity and could be a potential therapeutic target in TCL, as well as other hematological malignancies with interrupted Ras signaling pathways.

Loss of ATF3 promotes Akt activation and prostate cancer development in a Pten knockout mouse model

Activating transcription factor 3 (ATF3) responds to diverse cellular stresses, and regulates oncogenic activities (for example, proliferation, survival and migration) through direct transcriptional regulation or protein-protein interactions. Although aberrant ATF3 expression is frequently found in human cancers, the role of ATF3 in tumorigenesis is poorly understood. Here, we demonstrate that ATF3 suppresses the development of prostate cancer induced by knockout of the tumor suppressor Pten in mouse prostates. Whereas the oncogenic stress elicited by Pten loss induced ATF3 expression in prostate epithelium, we found that ATF3 deficiency increased cell proliferation and promoted cell survival, leading to early onset of mouse prostatic intraepithelial neoplasia and the progression of prostate lesions to invasive adenocarcinoma. Importantly, the loss of ATF3 promoted activation of the oncogenic AKT signaling evidenced by high levels of phosphorylated AKT and S6 proteins in ATF3-null prostate lesions. In line with these in vivo results, knockdown of ATF3 expression in human prostate cancer cells by single guided RNA-mediated targeting activated AKT and increased matrix metalloproteinase-9 expression. Our results thus link ATF3 to the AKT signaling, and suggest that ATF3 is a tumor suppressor for the major subset of prostate cancers harboring dysfunctional Pten.

First Report of Barley yellow striate mosaic virus on Wheat in China

In the spring of 2014, a survey of viral diseases on wheat (Triticum aestivum L.) was carried out in Hebei Province, China. The samples with virus-like symptoms of dwarfing and flag leaf yellowing were collected in Zhaoxian, Quyang, Anxin, and Luannan. To reproduce the viral symptoms and confirm whether the unknown virus was transmitted by insect vectors, the nymphs of aviruliferous planthopper (Laodelphax striatellus Fallen, Homoptera: Delphacidae) were transferred onto diseased wheat from the field for a 3-day acquisition access period and a 10-day incubation on fresh wheat seedlings, and then were exposed to 2- to 3-leaf stage wheat seedlings of wheat variety Shixin828 for a 3-day inoculation access period. The infected wheat plants developed mosaic symptoms on the young leaves at 7 days post inoculation (dpi), and followed with severe symptoms including stunting, chlorotic spots, and striation along the veins of leaves at around 14 dpi. The infection symptoms were same as in the field but distinct from wheat infected with Rice black streaked dwarf virus (RBSDV) or Northern cereal mosaic virus (NCMV). For further confirmation, total RNA was extracted from the symptomatic wheat leaves, and NCMV specific primers, NCMV-PF/NCMV-PR (5'-ATGGATAAGAAAGCAAGTGGA-3'/5'-TTAAAAGTCGGCATACGGGTC-3') and RBSDV specific primers, S10-F/S10-R (5'-TTACCCAACATCACGCAACT-3'/5'-GAGCAGGAACTTCACGACAAC-3') were used for amplification of sequences of phosphoprotein and coat protein genes, respectively. Neither RBSDV nor NCMV were present in the symptomatic tissue according to the RT-PCR assay (4). Tissues derived from symptomatic wheat leaves were fixed and embedded in Spurr's resin and used for ultra-thin sectioning and transmission electron microscopy observations, revealing large amounts of Rhabdovirus-like particles in the cytoplasm. The identified particles were about 315 to 353 × 46 to 57 nm, similar in size to Barley yellow striate mosaic virus (BYSMV), a member of the genus Cytorhabdovirus reported from Italy (2). The specific primer pair (5'-ACTAAGGGGGTACTCCGACC-3' and 5'-CTGATCTGCTTTGAGGGGCA-3') was designed based on the reported polymerase (L) gene sequence of BYSMV isolate Zanjan-1 (GenBank Accession No. FJ665628) (1), and used for the BYSMV detection by RT-PCR. A single bright band of the expected size (~500 bp) was obtained from total RNA extracted from the plants exhibiting symptoms in the greenhouse. No such band was amplified from asymptomatic plants, while 15 out of 23 field samples also produced the same 500-bp products in RT-PCR. PCR products from three virus-positive field samples were sequenced directly and the sequences were submitted to GenBank (KM052176, KM052177, and KM052178). BLAST search showed that the sequences shared 96 to 97% nucleotide identity with the polymerase L gene sequence of BYSMV isolate Zanjan-1, whereas only 73 to 75% identity with NCMV (AB030277 and GU985153) (1,3,5). To our knowledge, this is the first report of BYSMV occurrence on wheat in China. References: (1) R. Almasi et al. J. Phytopathol. 158:351, 2010. (2) A. Appiano et al. Cytol. 6:105, 1974. (3) H. C. Chen et al. Sci. Agric. Sinica 3:64, 1980. (4) X. F. Duan et al. Acta Phytopathol. Sinica 40:337, 2010. (5) F. Tanno et al. Arch. Virol. 145:1373, 2000.

Epidemiological characteristics of motor neuron disease in Chinese patients

BACKGROUND

The epidemiology, diagnosis, and treatment of motor neuron disease (MND) in Chinese patients are ill known.

METHODS

A registered study of 461 MND patients was conducted across 10 facilities in 7 Chinese cities from February 2009 to March 2010.

RESULTS

Patients were classified as amyotrophic lateral sclerosis (ALS) (84.4%), progressive bulbar palsy (PBP) (4.1%), progressive muscular atrophy (PMA) (10.4%), or primary lateral sclerosis (PLS) (0.9%). MND was predominant in men (men/women; 1.6:1.0). Mean onset age was 52.6 years, with the highest incidence being observed between 51 and 60 years. Notably, 26.0% of MND patients were employed in forestry, fishery, or animal husbandry industries. Ten cases (2.7%) reported family history of MND, and 54.2% exhibited cervical onset. MND was also associated with head/neck trauma. Non-invasive positive pressure ventilation was the most common supportive therapy.

CONCLUSION

As a novel comprehensive report of a Chinese population, this study reveals that epidemiological characteristics of MND patients were similar to those observed in international populations. MND is age-related, male gender predominant, and may be associated with both environmental and genetic risk factors.

Activation of mTOR pathway in myeloid-derived suppressor cells stimulates cancer cell proliferation and metastasis in lal(-/-) mice

Inflammation critically contributes to cancer metastasis, in which myeloid-derived suppressor cells (MDSCs) are an important participant. Although MDSCs are known to suppress immune surveillance, their roles in directly stimulating cancer cell proliferation and metastasis currently remain unclear. Lysosomal acid lipase (LAL) deficiency causes systemic expansion and infiltration of MDSCs in multiple organs and subsequent inflammation. In the LAL-deficient (lal^−/−) mouse model, melanoma metastasized massively in allogeneic lal^−/− mice, which was suppressed in allogeneic lal^+/+ mice due to immune rejection. Here we report for the first time that MDSCs from lal^−/− mice directly stimulated B16 melanoma cell in vitro proliferation, and in vivo growth and metastasis. Cytokines i.e., IL-1β and TNFα from MDSCs are required for B16 melanoma cell proliferation in vitro. Myeloid-specific expression of human LAL (hLAL) in lal^−/− mice rescues these malignant phenotypes in vitro and in vivo. The tumor-promoting function of lal^−/− MDSCs is mediated, at least in part, through over-activation of the mammalian target of rapamycin (mTOR) pathway. Knockdown of mTOR, Raptor or Rictor in lal^−/− MDSCs suppressed their stimulation on proliferation of cancer cells, including B16 melanoma, LLC and Tramp-C2 cancer cells. Our results indicate that LAL plays a critical role in regulating MDSCs ability to directly stimulate cancer cell proliferation, and overcome immune rejection of cancer metastasis in allogeneic mice through modulation of the mTOR pathway, which provides a mechanistic basis for targeting MDSCs to reduce the risk of cancer metastasis. Therefore, MDSCs possess dual functions to facilitate cancer metastasis: suppress immune surveillance, and stimulate cancer cell proliferation and growth.