Cathepsin B degrades RbcL during freezing-induced programmed cell death in Arabidopsis.

KEY MESSAGE: Cathepsin B plays an important role that degrades the Rubisco large subunit RbcL in freezing stress. Programmed cell death (PCD) has been well documented in both development and in response to environmental stresses in plants, however, PCD induced by freezing stress and its molecular mechanisms remain poorly understood. In the present study, we characterized freezing-induced PCD and explored its mechanisms in Arabidopsis. PCD induced by freezing stress was similar to that induced by other stresses and senescence in Arabidopsis plants with cold acclimation. Inhibitor treatment assays and immunoblotting indicated that cathepsin B mainly contributed to increased caspase-3-like activity during freezing-induced PCD. Cathepsin B was involved in freezing-induced PCD and degraded the large subunit, RbcL, of Rubisco. Our results demonstrate an essential regulatory mechanism of cathepsin B for Rubisco degradation in freezing-induced PCD, improving our understanding of freezing-induced cell death and nitrogen and carbohydrate remobilisation in plants.

Lentivirus-mediated CD/TK fusion gene transfection neural stem cell therapy for C6 glioblastoma.

A suicide gene can convert nontoxic prodrugs into toxic products to kill tumor cells. In this study, our aim was to transfect lentivirus-mediated CD/TK fusion gene into Wistar rat's neural stem cells (NSC) and then implant the NSC into a C6 glioma model to observe a C6 glioma growth inhibition effect. Primary NSC and stable transfection CD/TK fusion gene cell lines were established. To observe the tumor size and rat survival period in different groups, C6 glioma cell apoptosis and cell viability rate were applied to analyze the tumor inhibition effect of the neural stem cells' transfected CD/TK fusion gene. C6 cell viability showed that CDglyTK-NSC + GCV/5-Fc (group 1) was lower than CDglyTK-NSC (group 2), NSC + GCV/5-Fc (group 3), and control (group 4) from day 2 (p < 0.05), and the apoptosis rate was higher in group 1 compared with that of other groups (50.6%, p < 0.05) either in vitro or in vivo (35.47%, p < 0.05); both cell viability and apoptosis had no significance in the other three groups. In vivo, tumor size in group 1 was 7.76 ± 1.37 mm(3), which is smaller than the others (group2 27.28 ± 4.11 mm(3), group3 27.94 ± 2.08 and 28.61 ± 2.97 mm(3); p < 0.05). The other groups' tumor size was not significant (p > 0.05). Survival time of rats treated with CDglyTK-NSC + GCV/5-Fc (group 1) was significantly longer than that of the other groups (p < 0.05; group 1 48.86 ± 1.97, group 2 28.67 ± 3.75, group 3 31.5 ± 1.27, group 4 29.3 ± 1.33). We also showed that the transfected C6 cells had a migratory capacity toward gliomas in vivo. Transfected CD/TK fusion gene neural stem cells combined with propyl-guanosine and 5-flucytosine double prodrug significantly inhibit the development of glioma.

Location Optimization of Urban Fire Stations Considering the Backup Coverage.

Urban fires threaten the economic stability and safety of urban residents. Therefore, the limited number of fire stations should cover as many places as possible. Moreover, places with high fire risk should be covered by more fire stations. To optimize the location of urban fire stations, we construct a multi-objective optimization model for fire station planning based on the backup coverage model. The improved value of environment and ecosystem (SAVEE) model is introduced to quantify the spatial heterogeneity of urban fires. The main city zone of Wuhan is used as the study area to validate the proposed method. The results show that, considering the existing fire stations (85 facilities), the proposed model achieves a significant 38.56% in high-risk areas that can be covered by more than one fire station. If the existing fire stations are not considered when building 95 fire stations, the proposed model can achieve coverage of 50.07% in high-risk areas by utilizing more than one fire station. As a result, the proposed backup coverage model would perform better if the protection of high-risk areas is improved with as few fire stations as possible to guarantee more places covered.

Destabilization of coxsackievirus b3 genome integrated with enhanced green fluorescent protein gene.

AIMS: To evaluate the stability of coxsackievirus B (CVB) genome integrated with the enhanced green fluorescent protein gene (egfp) and provide valuable information for the use of the recombinant CVB variant. METHODS: A CVB3 variant expressing eGFP was constructed by insertion of the egfp open-reading frame (ORF) at the 5' end of CVB3 ORF. The recombinant virus CVB3-eGFP was serially passaged in HeLa cells. The deletions in the CVB3-eGFP genome around egfp were examined by reverse transcription polymerase chain reaction and sequencing. RESULTS: Genomic deletions of CVB3-eGFP could be observed as early as the 2nd passage. Sequencing showed that the genomic deletions caused either viral ORF shifts or partial deletions of the viral VP4 coding sequence. The 6th passage of CVB3-eGFP was checked by plaque assay for eGFP expression. All plaque-like foci showed eGFP expression. eGFP expression was also viewed in HeLa cells infected with plaque-forming viruses. CONCLUSIONS: The insertion of egfp destabilized the CVB3 genome. The genomic deletions led to lethal mutations because of the termination of viral protein synthesis due to viral ORF shift and loss of partial viral gene. These findings imply that experimental data based on CVB integrated with the reporter gene should be interpreted with caution.

Immune heterogeneity and clinicopathologic characterization of IGFBP2 in 2447 glioma samples.

Glioblastoma is an immunosuppressive, deadly brain tumor. IGFBP2, a circulating biomarker for cancer diagnosis and a potential immunotherapeutic target, is attracting more and more attention from oncologists and clinicians. Thus, it is urgent to thoroughly investigate the immune biological process of IGFBP2 to understand tumor immune complexity and provide potential evidence for anti-IGFBP2 therapy. Through authoritative public databases, we enrolled a total of 2447 glioma samples with gene expression profiles. Then, the clinical characteristics and immunosuppressive status of IGFBP2 in the glioma samples were analyzed. Immunohistochemical staining detected the expression of immunosuppressive biomarkers. We found that IGFBP2 expression was upregulated in high-grade glioma and GBM and downregulated in IDH mutant glioma. Increased IGFBP2 accompanied PTEN loss and EGFR amplification. Bioinformatic analysis revealed that IGFBP2 is related to immunological processes. We further selected specific immunologic related gene sets and found IGFBP2 predominated immunosuppressive activities in GBM. Furthermore, we explored the relationship between IGFBP2 and genes that were well-characterized glioma-mediated immunosuppressive molecules to investigate the potential effect of IGFBP2. We discovered that IGFBP2 was correlated with CHI3L1, TNFRSF1A, LGALS1, TIMP1, VEGFA, ANXA1 and LGALS3, which were classic immunosuppressive biomarkers. Higher IGFBP2 expression predicted unfavorable survival for patients with GBM. Our findings implied that IGFBP2 is involved in immunosuppressive activities and is an independent unfavorable prognostic biomarker for patients with GBM. IGFBP2 is a potential immunotherapeutic target for GBM in future clinical trials.

MicroRNA-326 sensitizes human glioblastoma cells to curcumin via the SHH/GLI1 signaling pathway.

Glioblastoma multiforme is the most malignant and common brain tumor in adults and is characterized by poor survival and high resistance to chemotherapy and radiotherapy. Among the new chemotherapy drugs, curcumin, a popular dietary supplement, has proven to have a potent anticancer effect on a variety of cancer cell types; however, it remains difficult to achieve a satisfactory therapeutic effect with curcumin using the traditional single-drug treatment. In this study, we found that expression of miR-326, a tumor suppressor microRNA in various tumor types, resulted in a marked increase of curcumin-induced cytotoxicity and apoptosis and a decrease of proliferation and migration in glioma cells. Moreover, we found that combination treatment of miR-326 and curcumin caused significant inhibition of the SHH/GLI1 pathway in glioma cells compared with either treatment alone, independent of p53 status. Furthermore, in vivo, the curcumin-induced increase in miR-326 expression altered the anti-glioma mechanism of this combination treatment, which further reduced tumor volume and prolonged the survival period compared to either treatment alone. Taken together, our data strongly support an important role for miR-326 in enhancing the chemosensitivity of glioma cells to curcumin.

Targeting the SMO oncogene by miR-326 inhibits glioma biological behaviors and stemness.

BACKGROUND: Few studies have associated microRNAs (miRNAs) with the hedgehog (Hh) pathway. Here, we investigated whether targeting smoothened (SMO) with miR-326 would affect glioma biological behavior and stemness. METHODS: To investigate the expression of SMO and miR-326 in glioma specimens and cell lines, we utilized quantitative real-time (qRT)-PCR, Western blot, immunohistochemistry, and fluorescence in situ hybridization. The luciferase reporter assay was used to verify the relationship between SMO and miR-326. We performed cell counting kit-8, transwell, and flow cytometric assays using annexin-V labeling to detect changes after transfection with siRNA against SMO or miR-326. qRT-PCR assays, neurosphere formation, and immunofluorescence were utilized to detect the modification of self-renewal and stemness in U251 tumor stem cells. A U251-implanted intracranial model was used to study the effect of miR-326 on tumor volume and SMO suppression efficacy. RESULTS: SMO was upregulated in gliomas and was associated with tumor grade and survival period. SMO inhibition suppressed the biological behaviors of glioma cells. SMO expression was inversely correlated with miR-326 and was identified as a novel direct target of miR-326. miR-326 overexpression not only repressed SMO and downstream genes but also decreased the activity of the Hh pathway. Moreover, miR-326 overexpression decreased self-renewal and stemness and partially prompted differentiation in U251 tumor stem cells. In turn, the inhibition of Hh partially elevated miR-326 expression. Intracranial tumorigenicity induced by the transfection of miR-326 was reduced and was partially mediated by the decreased SMO expression. CONCLUSIONS: This work suggests a possible molecular mechanism of the miR- 326/SMO axis, which can be a potential alternative therapeutic pathway for gliomas.

Enhancement of nystatin production by redirecting precursor fluxes after disruption of the tetramycin gene from Streptomyces ahygroscopicus.

Complete and independent tetramycin and nystatin gene clusters containing varying lengths of type I polyketide synthase (PKS) genes were isolated from Streptomyces ahygroscopicus, a producer of tetramycin (a tetraene) in large amounts and nystatin A1 (a heptaene) in small amounts. Tetramycin was similar to pimaricin, and nystatin A1 was similar to amphotericin. All these polyene macrolide antibiotics possessed the same macrolactone ring biosynthesized from coenzyme A precursors by PKSs but had different number of atoms in the macrolactone ring and side groups. Because tetramycin and nystatin shared limited coenzyme A precursors in the same producer organism, blocking the consumption of precursors in tetramycin pathway may increase the coenzyme A pool. Thus, we genetically manipulated the tetramycin PKS to enhance nystatin production. The type I PKS ttmS1 gene mutant abolished production of tetramycin and had a beneficial effect on the production of nystatin A1. For the mutant, the yield of nystatin A1 was increased by 10-fold compared to that of the wild-type. Thus, deletion of the tetramycin pathway redirected precursor metabolic fluxes and provided an easy genetic approach to manipulate organisms and to increase production levels of a precise target.

Suppressor of fused (Sufu) represses Gli1 transcription and nuclear accumulation, inhibits glioma cell proliferation, invasion and vasculogenic mimicry, improving glioma chemo-sensitivity and prognosis.

Glioblastoma are highly aggressive brain tumors with poor prognosis. While various dysregulation of signaling pathways in gliomas have been described, the identification of biomarkers and therapy targets remains an important task for novel diagnostic and therapeutic approaches. Here we described that the Suppressor of fused (also known as Sufu) is significantly down-regulated in high-grade gliomas, correlating with a poor prognosis. We demonstrated that ectopic expression of Sufu inhibited cell proliferation, invasion and vasculogenic mimicry. In addition, overexpression of Sufu reduced Gli reporter gene transcription activity and prevented Gli1 nuclear accumulation, whereas knockdown of Sufu reversed these effects. Furthermore, overexpressed Sufu sensitized glioblastoma to Temozolomide and Cyclopamine. Thus, Sufu is potential tumor suppressor and therapeutic target in glioblastoma.

ß-elemene induces caspase-dependent apoptosis in human glioma cells in vitro through the upregulation of Bax and Fas/ FasL and downregulation of Bcl-2.

BACKGROUND: ß-elemene, extracted from herb medicine Curcuma wenyujin has potent anti-tumor effects in various cancer cell lines. However, the activity of ß-elemene against glioma cells remains unclear. In the present study, we assessed effects of ß-elemene on human glioma cells and explored the underlying mechanism. MATERIALS AND METHODS: Human glioma U87 cells were used. Cell proliferation was determined with MTT assay and colony formation assay to detect the effect of ß-elemene at different doses and times. Fluorescence microscopy was used to observe cell apoptosis with Hoechst 33258 staining and change of glioma apoptosis and cell cycling were analyzed by flow cytometry. Real-time quantitative PCR and Western-blotting assay were performed to investigated the influence of ß-elemene on expression levels of Fas/FasL, caspase-3, Bcl-2 and Bax. The experiment was divided into two groups: the blank control group and ß-elemne treatment group. RESULTS: With increase in the concentration of ß-elemene, cytotoxic effects were enhanced in the glioma cell line and the concentration of inhibited cell viability (IC50) was 48.5 µg/mL for 24h. ß-elemene could induce cell cycle arrest in the G0/G1 phase. With Hoechst 33258 staining, apoptotic nuclear morphological changes were observed. Activation of caspase-3,-8 and -9 was increased and the pro-apoptotic factors Fas/FasL and Bax were upregulated, while the anti-apoptotic Bcl-2 was downregulated after treatment with ß-elemene at both mRNA and protein levels. Furthermore, proliferation and colony formation by U87 cells were inhibited by ß-elemene in a time and does- dependent manner. CONCLUSIONS: Our results indicate that ß-elemene inhibits growth and induces apoptosis of human glioma cells in vitro. The induction of apoptosis appears to be related with the upregulation of Fas/FasL and Bax, activation of caspase-3,-8 and -9 and downregulation of Bcl-2, which then trigger major apoptotic cascades.

Study of TNF-α, IL-1ß and LPS levels in the gingival crevicular fluid of a rat model of diabetes mellitus and periodontitis.

OBJECTIVE: In this study, we sought to investigate the dynamic changes in the levels of TNF-α, IL-1ß and LPS in the gingival crevicular fluid (GCF) in a rat model of diabetes mellitus (DM) and periodontitis (PD). Additionally, we evaluated alveolar bone loss and the histopathological response associated with experimental diabetes mellitus and experimental periodontitis. METHODS: DM and PD were induced together in 15 rats (group 1) by streptozotocin injection and ligature induction. Periodontitis alone was produced by ligature induction in 15 rats (group 2), diabetes alone was produced by streptozotocin injection in 15 rats (group 3), and fifteen systemically and periodontally healthy rats were used as controls (group 4). The gingival TNF-α, IL-1ß and LPS levels were measured by using ELISA method. Periodontal destruction was assessed by measuring the alveolar bone loss. Periodontal inflammation was quantified by histopathological grading in H&E stained samples. RESULTS: Higher levels of TNF-α, IL1-ß and LPS, increased alveolar bone loss and more serve histopathology were found in group 1 compared with group 2, group 3 and group 4 (p< 0.05). The quantities of TNF-α, IL1-ß and LPS, the amount of alveolar bone loss and the severity of the histopathological finding were greater in group 2 than group 3 and group 4 (p< 0.05). Group 3 demonstrated higher levels of TNF-α, IL1-ß and LPS, increased alveolar bone loss and more serve histopathology than group 4 (p< 0.05). Statistically significant differences were noted between all of the groups. CONCLUSIONS: These data indicate that DM may lead to enhanced TNF-α, IL1-ß and LPS production in the periodontal tissues. The resorption values of alveolar bone and the histological inflammation were more severe in rats with periodontitis and diabetes mellitus than in those with periodontitis alone, diabetes mellitus alone and control rats. Our findings are consistent with the hypothesis that hyperglycemia contributes to the heightened inflammatory response associated with periodontitis.

Curcumin suppresses malignant glioma cells growth and induces apoptosis by inhibition of SHH/GLI1 signaling pathway in vitro and vivo.

AIMS: To study the role of curcumin on glioma cells via the SHH/GLI1 pathway in vitro and vivo. METHODS: The effects of curcumin on proliferation, migration, apoptosis, SHH/GLI1 signaling, and GLI1 target genes expression were evaluated in multiple glioma cell lines in vitro. A U87-implanted nude mice model was used to study the role of curcumin on tumor volume and the suppression efficacy of GLI1. RESULTS: Curcumin showed cytotoxic effects on glioma cell lines in vitro. Both mRNA and protein levels of SHH/GLI1 signaling (Shh, Smo, GLI1) were downregulated in a dose- and time-dependent manner. Several GLI1-dependent target genes (CyclinD1, Bcl-2, Foxm1) were also downregulated. Curcumin treatment prevented GLI1 translocating into the cell nucleus and reduced the concentration of its reporter. Curcumin suppressed cell proliferation, colony formation, migration, and induced apoptosis which was mediated partly through the mitochondrial pathway after an increase in the ratio of Bax to Bcl2. Intraperitoneal injection of curcumin in vivo reduced tumor volume, GLI1 expression, the number of positively stained cells, and prolonged the survival period compared with the control group. CONCLUSION: This study shows that curcumin holds a great promise for SHH/GLI1 targeted therapy against gliomas.