The impact of street greenery on active travel: a narrative systematic review.

Background: Street greenery may have a profound effect on residents' active travel (AT), a mode of transportation involving walking and cycling. This study systematically reviewed the scientific evidence on the effects of street greenery on active travel. Methods: A comprehensive search was performed using keywords and references in PubMed, Web of Science, Scopus, and Cochrane Library. The review included studies that met the following criteria: (1) Study design: experimental studies, cross sectional studies, (2) Participants: individuals of all ages, (3) Exposure variables: street greenery, including street vegetation (e.g., trees, shrubs, and lawns), (4) Outcomes: active travel behaviors (walking, cycling), (5) Article type: peer-reviewed articles, (6) Search time window: from the inception of relevant electronic literature database until 21 June 2023, (7) Geographic scope: worldwide; (8) Language: articles in English. Results: Twenty-six cross-sectional studies met the inclusion criteria and were analyzed. These studies employed objective metrics for assessing street greenery and varied methodologies to measure AT, including 14 using subjective measurements (like self-reported surveys), 10 using objective data (such as mobile app analytics), and two studies combined both approaches. This review identifies a generally positive impact of street greenery on active travel in various aspects. However, the extent of this influence varies with factors such as temporal factors (weekdays vs. weekends), demographic segments (age and gender), proximity parameters (buffer distances), and green space quantification techniques. Street greenness promotes active travel by enhancing environmental esthetics, safety, and comfort, while also improving air quality, reducing noise, and fostering social interactions. In addition, the study suggests that variables like weather, seasonality, and cultural context may also correlate with the effectiveness of street greenery in encouraging active travel. Conclusion: Street greenery positively influences active travel, contributing to public health and environmental sustainability. However, the findings also indicate the need for more granular, experimental, and longitudinal studies to better understand this relationship and the underlying mechanisms. These insights are pivotal for urban planners and policymakers in optimizing green infrastructure to promote active transportation, taking into account local demographics, socio-economic factors, and urban design.

SDCBP modulates tumor microenvironment, tumor progression and anti-PD1 efficacy in colorectal cancer.

Anti-programmed cell death 1 (aPD1) therapy has yielded limited success in patients with colorectal cancer (CRC). Syndecan binding protein (SDCBP), encodes a PDZ domain-containing protein that is essential for cellular processes, including cell adhesion, migration, and signal transduction. Here, we investigated the effect of SDCBP on tumor progression, immunotherapy, and the tumor microenvironment (TME) in CRC. High expression of SDCBP is associated with non-response to immunotherapy and correlated with poorer disease-free survival (DFS) in CRC patients. Inhibiting SDCBP by transfecting shRNA or using its inhibitor zinc pyrithione (ZnPT) hindered proliferation and metastasis while enhancing the efficacy of aPD1 treatment in a mouse xenograft model and liver metastasis model. The TME of CRC was significantly altered following ZnPT treatment characterized by a reduced amount of M2 macrophages and a heightened percentage of M1 macrophages. The co-culture system of CRC cells and macrophages provided evidence that SDCBP silencing promoted the repolarisation of M2 macrophages into M1. SDCBP promotes the proliferation, metastasis, and immunotherapy resistance of CRC. Thus, ZnPT represents an effective SDCBP inhibitor and exhibits considerable potential for combination with aPD1 to enhance immunotherapy efficacy.

Perillaldehyde Mitigates Ionizing Radiation-Induced Intestinal Injury by Inhibiting Ferroptosis via the Nrf2 Signaling Pathway.

SCOPE: Gastrointestinal toxicity is one of the major side effects of abdominopelvic tumor radiotherapy. Studies have shown that perillaldehyde (PAH) has antioxidant, antiinflammatory, antimicrobial activity, and antitumor effects. This study aims to determine whether PAH has radioprotective effects on radiation-induced intestinal injury and explore the underlying mechanisms. METHODS AND RESULTS: C57BL/6J mice are gavaged with PAH for 7 days, then exposed to a single dose of 13 Gy X-ray total abdominal irradiation (TAI). PAH treatment prolongs the survival time, promotes the survival of crypt cells, attenuates radiation-induced DNA damage, and mitigates intestinal barrier damage in the irradiated mice. PAH also shows radioprotective effects in intestinal crypt organoids and human intestinal epithelial cells (HIEC-6). PAH-mediated radioprotection is associated with the upregulation of nuclear factor erythroid-2 related factor 2 (Nrf2), activation of the antioxidant pathway, and inhibition of ferroptosis. Notably, treatment with the Nrf2 inhibitor ML385 abolishes the protective effects of PAH, indicating that Nrf2 activation is essential for PAH activity. CONCLUSION: PAH inhibits ionizing radiation (IR)-induced ferroptosis and attenuates intestinal injury after irradiation by activating Nrf2 signaling. Therefore, PAH is a promising therapeutic strategy for IR-induced intestinal injury.

Identification of microRNAs Responding to Aluminium, Cadmium and Salt Stresses in Barley Roots.

Plants are frequently exposed to various abiotic stresses, including aluminum, cadmium and salinity stress. Barley (Hordeum vulgare) displays wide genetic diversity in its tolerance to various abiotic stresses. In this study, small RNA and degradome libraries from the roots of a barley cultivar, Golden Promise, treated with aluminum, cadmium and salt or controls were constructed to understand the molecular mechanisms of microRNAs in regulating tolerance to these stresses. A total of 525 microRNAs including 198 known and 327 novel members were identified through high-throughput sequencing. Among these, 31 microRNAs in 17 families were responsive to these stresses, and Gene Ontology (GO) analysis revealed that their targeting genes were mostly highlighted as transcription factors. Furthermore, five (miR166a, miR166a-3p, miR167b-5p, miR172b-3p and miR390), four (MIR159a, miR160a, miR172b-5p and miR393) and three (miR156a, miR156d and miR171a-3p) microRNAs were specifically responsive to aluminum, cadmium and salt stress, respectively. Six miRNAs, i.e., miR156b, miR166a-5p, miR169a, miR171a-5p, miR394 and miR396e, were involved in the responses to the three stresses, with different expression patterns. A model of microRNAs responding to aluminum, cadmium and salt stresses was proposed, which may be helpful in comprehensively understanding the mechanisms of microRNAs in regulating stress tolerance in barley.

Analyzing the Effect of Vitronectin on Cell Growth and Mesenchymal-Epithelial Transition of Pulmonary Fibroblast Cells.

PURPOSE: Vitronectin (VTN), a multifunctional glycoprotein, is involved in various biological and pathological processes. The purpose of this study was to explore the effect of VTN on mesenchymal-epithelial transition (MET) of pulmonary fibroblast cells. METHODS: Lentivirus encoding for VTN-specific shRNA was constructed and infected into the cultured fibroblast WI-38 cells. Real-time PCR and Western blot were applied to examine the expression of VTN in WI-38 cells. MTT assay was used to assess cell proliferation. Western blot was conducted to examine the expression of MET-related and apoptosis-related proteins. RESULTS: The knockdown of VTN significantly inhibited the growth of WI-38 cells compared to the control group. Meanwhile, knockdown of VTN remarkably increased the expression of Bax and Caspase 3 compared with the control group. Furthermore, knockdown of VTN significantly promoted the expression of E-cadherin in comparison to control group. CONCLUSIONS: Knockdown of VTN promoted the expression of apoptosis-related factors, meanwhile, facilitated the MET process of fibroblast cells by regulating the expression of relevant factors. In sum, VTN performed a potential regulator in cell growth and MET of pulmonary fibroblast cells, which can be considered as a potential target for diagnose and therapy of relevant diseases.

The PI3K/mTOR Inhibitor Ompalisib Suppresses Nonhomologous End Joining and Sensitizes Cancer Cells to Radio- and Chemotherapy.

As the predominant pathway for the repair of DNA double-strand breaks (DSB), non-homologous end joining (NHEJ) attenuates the efficacy of cancer treatment which relies on the introduction of DSBs, such as radiotherapy and genotoxic drugs. Identifying novel NHEJ inhibitors is of great importance for improving the therapeutic efficiency of radio- or chemotherapy. Here we miniaturized our recently developed NHEJ detecting system into a 96-well plate-based format and interrogated an FDA approved drug library containing 1732 compounds. A collection of novel hits were considered to be potential DSB repair inhibitors at the noncytotoxic concentration. We identified omipalisib as an efficient sensitizer for DNA damage-induced cell death in vitro Furthermore, in vitro analysis uncovered the repressive effect of omipalisib on the phosphorylation of DNA-dependent protein kinase catalytic subunit induced by ionizing radiation and doxorubicin, which led to the suppression of NHEJ pathway. IMPLICATIONS: In summary, our findings suggested the possibility for repurposing these candidates as radio- or chemosensitizers, which might extend their clinical application in cancer therapy.

Genetic variations in DNA repair gene NEIL1 associated with radiation pneumonitis risk in lung cancer patients.

BACKGROUND: Radiation pneumonitis (RP) is a common side effect in lung cancer patients who received radiotherapy. Our previous study found genetic variations in DNA repair gene NEIL1 may be a predictor of RP in patients with esophageal cancer. So, we hypothesis genetic variations in NEIL1 gene could affect the risk of RP in lung cancer patients following radiotherapy. METHODS: Genetic variations rs4462560 G>C and rs7402844 C>G in NEIL1 gene were genotyped in 174 lung cancer patients received radio(chemo)therapy. Luciferase assay, real-time PCR and Western blot were used to access the effect of the variants on NEIL1 in HELF and HEF cell lines which were transfected with plasmids containing rs4462560 G>C and rs7402844 C>G. RESULTS: Patients with rs4462560 CC genotype had a lower risk of RP grade ≥2 than GG genotype. Compared with the CC genotype, rs7402844 GG genotype was associated with an increased RP grade ≥2 risk. What is more, rs4462560 G decreased the relative luciferase activity of NEIL1 gene promoter compared with the negative control in vitro, while rs4462560 C can increase the relative luciferase activity. The mRNA and protein level of the NEIL1 gene in rs4462560 G were lower than rs4462560 C. CONCLUSIONS: Genetic variants of NEIL1 are associated with RP risk through regulation of NEIL1 expression and serve as independent biomarkers for prediction of RP in patients treated with thoracic radiotherapy.

The Plasma Levels and Polymorphisms of Vitronectin Predict Radiation Pneumonitis in Patients With Lung Cancer Receiving Thoracic Radiation Therapy.

PURPOSE: Our previous findings have identified vitronectin (VTN) as a potential biomarker for radiation pneumonitis (RP) through proteomics and molecular mechanism studies. In a recent study, we further explored associations of plasma level and single nucleotide polymorphisms of VTN with the risk of RP in patients with lung cancer receiving radiation therapy. METHODS AND MATERIALS: A total of 165 patients with lung cancer were prospectively enrolled with detection of VTN concentration before radiation therapy. VTN reference single nucleotide polymorphisms, rs704 and rs2227721, were genotyped by Taqman probe method. Cox proportional hazard models were performed to identify clinical variables and genotypes associated with the risk of RP on univariate and multivariate analyses, and t tests and analysis of variance were conducted to evaluate the expression level of VTN. RESULTS: The baseline secretion level of VTN in patients with grade ≥3 RP was significantly higher than that in grade <3 RP patients (P < .0001), and elevated levels were observed in patients having the AA genotype compared with GA/GG genotypes of rs704. The VTN rs704 GA/GG and rs2227721 AA/AC genotypes had a significantly lower risk of RP (hazard ratio [HR], 0.448, P = .005; HR, 0.419, P = .008, respectively). In addition, combining cut-off values of mean lung dose (MLD) and VTN plasma level, grade ≥3 RP risk groupings were as follows: high risk: MLD ≥12 Gy and VTN level ≥132 µg/mL (RP rate, 10 of 16 patients, 62.5%); intermediate risk: MLD ≥12 Gy and VTN level <132 µg/mL or MLD <12 Gy and VTN level ≥132 µg/mL (8 of 70 patients, 11.4%); and low risk: MLD <12 Gy and VTN level <132 µg/mL (1 of 79 patients, 1.3%) (P < .0001). CONCLUSIONS: Among patients receiving radiation therapy, relatively high plasma levels of VTN before radiation therapy were associated with the higher incidence of RP, and VTN rs704 and rs2227721 each had a significant effect on predicting RP risk. Combining VTN concentration with MLD appeared to facilitate stratification of patients with lung cancer who received radiation therapy into low-, intermediate-, and high-risk RP groups. This study indicated that VTN may serve as a blood biomarker for susceptibility to RP in patients with lung cancer.

NAD+ depletion radiosensitizes 2-DG-treated glioma cells by abolishing metabolic adaptation.

Two-deoxy-d-glucose (2-DG) mediated glucose restriction (GR) has been applied as a potential therapeutic strategy for tumor clinical treatments. However, increasing evidences have indicated that 2-DG alone is inefficient in killing tumor cells, and the effect of 2-DG on modifying tumor radio-responses also remains controversial. In this study, we found that 2-DG triggered metabolic adaption in U87 glioma cells by up-regulating nicotinamide phosphoribosyltransferase (NAMPT) and cellular NAD+ content, which abolished 2-DG-induced potential radiosensitizing effect in glioma cells. Strikingly, NAD+ depletion evoked notable oxidative stress by NADPH reduction and hence re-radiosensitized 2-DG-treated glioma cells. Furthermore, isocitrate dehydrogenase-1 (IDH1) mutant U87 glioma cells with deficiency in the rate-limiting enzyme of Preiss-Handler pathway nicotinate phosphoribosyltransferase (Naprt1) revealed notable 2-DG-induced oxidative stress and radiosensitization. Our findings implied that targeting NAD+ could radiosensitize gliomas with GR, and 2-DG administration could be benefit for tumor patients with IDH1 mutation.

Treatment of stage III non-small cell lung cancer in the era of immunotherapy: pathological complete response to neoadjuvant pembrolizumab and chemotherapy.

Non-small cell lung cancer (NSCLC) accounts for about 85% of all lung cancers. The expected 5-year survival of stage III NSCLC ranges from 13% to 36% for stage III. Due to the heterogeneity and poor efficacy of stage III patients, there is great controversy on how to optimize the therapy strategy. Immunotherapy is providing better clinical efficacy to more NSCLC patients, and is rapidly extending its range of care from advanced stage to locally advanced stage and early stage NSCLC. Due to the patient's strong treatment intention, drug availability, and a few encouraging results from clinical trials (NADIM, NCT02716038, etc.), the authors observed a case of stage III NSCLC that achieved complete remission after receiving neoadjuvant chemotherapy combined with immunotherapy. In view of such a satisfactory result in neoadjuvant therapy, this article discusses how comprehensive treatment for stage III NSCLC patients may be conducted and the manner in which various therapeutic techniques can be mastered in the era of immunotherapy. Immunotherapy has opened the exploratory space for finding resolutions to numerous challenges of treating stage III NSCLC. Further clinical studies and exploration of personalized treatment, guided by imaging data, and clinical and pathological biomarkers are imperative for the benefit of these patients.

IDH1-R132H mutation radiosensitizes U87MG glioma cells via epigenetic downregulation of TIGAR.

Isocitrate dehydrogenase 1 (IDH1) is the most frequently mutated gene in World Health Organization grade II-III and secondary glioma. The majority of IDH1 mutation cases involve the substitution from arginine to histidine at codon 132 (IDH1-R132H). Although the oncogenic role of IDH1-R132H has been confirmed, patients with IDH1-R132H brain tumors exhibit a better response to radiotherapy compared with those with wild-type (WT) IDH1. In the present study, the potential mechanism of radiosensitization mediated by IDH1-R132H was investigated by overexpressing IDH1-R132H in U87MG glioma cells. The results demonstrated decreased clonogenic capacity of IDH1-R132H-expressing cells, as well as delayed repair of DNA double-strand breaks compared with IDH1-WT. Data from The Cancer Genome Atlas were analyzed, which demonstrated that the expression of TP53-induced glycolysis and apoptosis regulator (TIGAR) was lower in patients with glioma harboring IDH1 mutations compared with that in patients with IDH1-WT. TIGAR-knockdown increases the radiosensitivity of glioma cells; in U87MG cells, IDH1-R132H suppressed TIGAR expression. Chromatin immunoprecipitation assays revealed increased levels of repressive H3K9me3 markers at the TIGAR promoter in IDH1-R132H compared with IDH1-WT. These data indicated that IDH1-R132H may overcome radioresistance in glioma cells through epigenetic suppression of TIGAR expression. However, these favorable effects were not observed in U87MG glioma stem-like cells. The results of the present study provide an improved understanding of the functionality of IDH1 mutations in glioma cells, which may improve the therapeutic efficacy of radiotherapy.

Relationship between vascular endothelial growth factor -2578C > a gene polymorphism and lung cancer risk: a meta-analysis.

BACKGROUND: Several reports were published on the relationship between the vascular endothelial growth factor (VEGF) -2578C > A gene polymorphism and lung cancer risk; however, the results are debatable. This meta-analysis was conducted to assess the relationship between VEGF -2578C > A gene polymorphism and lung cancer risk. METHODS: The associated literatures were identified on the 1st of September 2018 from CBM-disc (China Biological Medicine Database) and PubMed. RESULT: A total of 14 reports were recruited into our meta-analysis to assess the association between VEGF -2578C > A gene polymorphism and lung cancer susceptibility. There was a marked association between VEGF -2578C > A A allele / CC genotype and lung cancer risk in overall and Asian populations (overall populations: A allele: OR = 1.26, 95% CI: 1.08-1.46, P = 0.003; CC genotype: OR = 0.72, 95% CI: 0.54-0.95, P = 0.02; Asians: A allele: OR = 1.33, 95% CI: 1.15-1.55, P = 0.0002; CC genotype: OR = 0.68, 95% CI: 0.50-0.93, P = 0.01). However, VEGF -2578C > A gene polymorphism was not associated with the risk of lung cancer in Caucasians. CONCLUSION: VEGF -2578C > A A allele / CC genotype is associated with the lung cancer susceptibility in Asians and in overall populations.

Quantitative assessment of HR and NHEJ activities via CRISPR/Cas9-induced oligodeoxynucleotide-mediated DSB repair.

Homologous recombination (HR) and non-homologous end joining (NHEJ) are the two major mechanisms for the repair of DNA double-strand breaks (DSBs) in eukaryotic cells. Previously, we designed an assay for detecting NHEJ activity by using clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system, however, this approach cannot be used to predict the activity of HR repair. Hence, we developed a novel method that is capable of quantitatively measuring both HR and NHEJ activities via CRISPR/Cas9-induced oligodeoxynucleotide (ODN)-mediated DSB repair. In the present experimental procedures, the CRISPR/Cas9 plasmid was cotransfected with single-stranded ODN (ssODN) or blunt-ended double-stranded ODN (dsODN), both of which harbored a unique marker sequence. After the induction of site-specific DSBs by CRISPR/Cas9 system, the ssODN, functioned as the donor template for HR repair, could insert the marker sequence into the DSB sites, while the dsODN was embedded in the DSB sites through NHEJ pathway. Next, by means of PCR analysis using a specific primer for the marker sequence and the primers that flank the DSB sites, the relative amount of integrated marker sequence in the genomic DNA could be quantitatively determined. The correlation between the marker sequence abundance and the HR and NHEJ activities was confirmed by using the selective HR and NHEJ inhibitors. This accessible and rapid quantitative assay for HR and NHEJ activities might be useful for the future research of the DSB repair mechanisms.

Identification of microRNAs in response to aluminum stress in the roots of Tibetan wild barley and cultivated barley.

BACKGROUND: Barley is relatively sensitive to Aluminum (Al) toxicity among cereal crops, but shows a wide genotypic difference in Al tolerance. The well-known Al-tolerant mechanism in barley is related to Al exclusion mediated by a citrate transporter HvAACT1 (Al-activated citrate transporter 1). A 1-kb insertion in the promoter region of HvAACT1 gene results in a dramatic increase of its expression level, which only occurs in some Al-tolerant cultivars. However, Al-tolerant Tibetan wild barley accession XZ29 did not have the 1-kb insertion. RESULTS: We confirmed that the expression of HvAACT1 and secretion of citrate and other organic acids did not explain the difference in Al-tolerant wild barley XZ29 and Al-sensitive cultivated barley Golden Promise. To identify microRNAs (miRNAs) and their target genes responsive to Al stress in barley roots, eight small RNA libraries with two biological replicates from these two genotypes exposed to control and Al-treated conditions were constructed and submitted to deep sequencing. A total of 342 miRNAs were identified in Golden Promise and XZ29, with 296 miRNAs being commonly shared in the two genotypes. Target genes of these miRNAs were obtained through bioinformatics prediction or degradome identification. Comparative analysis detected 50 miRNAs responsive to Al stress, and some of them were found to be exclusively expressed in XZ29 and associated with Al tolerance. CONCLUSIONS: miRNAs exclusively expressing in the wild barley were identified and found to be associated with Al stress tolerance. The current results provide a model of describing the roles of some special miRNAs associated with Al tolerance in the Tibetan wild barley.

Radiosensitivity enhancement by combined treatment of nimotuzumab and celecoxib on nasopharyngeal carcinoma cells.

INTRODUCTION: In this study, the radiation-enhancing effects of combined treatment with nimotuzumab, a humanized EGFR-blocking antibody, and celecoxib, a COX-2 selective inhibitor, in human nasopharyngeal carcinoma (NPC) cells were investigated. MATERIALS AND METHODS: 3-(4,5-Dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide and clonogenic survival assays were done to evaluate the combined cytotoxic and radiosensitizing effects of nimotuzumab or celecoxib or the combination on CNE1 and CNE2 cells. Western blot analysis was performed to identify the effect of nimotuzumab and/or celecoxib with or without irradiation on the cytoplasmic and nuclear EGFR signaling pathways in CNE2 cells. RESULTS: Our results demonstrated that concurrent administration of nimotuzumab and celecoxib cooperatively enhanced the cytotoxicity and radiosensitivity of CNE2 cells but not CNE1 cells. The combination of both drugs with or without irradiation also cooperatively inhibited cytoplasmic and nuclear EGFR signaling pathways in CNE2 cells. CONCLUSION: Our results suggest a promising approach for the treatment of poorly differentiated NPC.

Metabolite profiling and gene expression of Na/K transporter analyses reveal mechanisms of the difference in salt tolerance between barley and rice.

Barley (Hordeum vulgare) and rice (Oryza sativa) differ greatly in their salt tolerance, although both species belong to the Poaceae family. To understand the mechanisms in the difference of salt tolerance between the two species, the responses of ionome, metabolome and gene expression of Na and K transporters to the different salt treatments were analyzed using 4 barley and 4 rice genotypes differing in salt tolerance. In comparison with 4 rice genotypes, four barley genotypes showed better plant growth, lower shoot Na concentration and higher K concentration at the 9 day after salt treatments. There was a dramatic difference in absolute expression levels of SOS, HKT and NHX family genes between barley and rice, which might account for their difference in Na/K homeostasis and salt tolerance. Moreover, rice leaves accumulated excess Na under salt treatments, which caused serious damages to physiological metabolisms based on metabolomic analysis, but barley leaves had lower Na concentration and small changes in the most metabolites. These results provide useful insights into the molecular mechanism in the difference of salt tolerance between rice and barley.

Ionomic, metabolomic and proteomic analyses reveal molecular mechanisms of root adaption to salt stress in Tibetan wild barley.

In our previous study, Tibetan wild barley (Hordeum spontaneum L.) has been found to be rich in the elite accessions with strong abiotic stress tolerance, including salt stress tolerance. However, the molecular mechanism of salt tolerance underlying the wild barley remains to be elucidated. In this study, two Tibetan wild barley accessions, XZ26 (salt-tolerant) and XZ169 (salt-sensitive), were used to investigate ionomic, metabolomic and proteomic responses in roots when exposed to 0, 200 (moderate) and 400 mM (high) salinity. XZ26 showed stronger root growth and maintained higher K concentrations when compared with XZ169 under moderate salinity, while no significant difference was found between the two accessions under high salinity. A total of 574 salt-regulated proteins and 153 salt-regulated metabolites were identified in the roots of both accessions based on quantitative proteomic (iTRAQ methods) and metabolomic (GC-TOF/MS) analysis. XZ26 developed its root adaptive strategies mainly by accumulating more compatible solutes such as proline and inositol, acquiring greater antioxidant ability to cope with ROS, and consuming less energy under salt stress for producing biomass. These findings provide a better understanding of molecular responses of root adaptive strategies to salt stress in the wild barley.

A CRISPR/Cas9-Based Screening for Non-Homologous End Joining Inhibitors Reveals Ouabain and Penfluridol as Radiosensitizers.

Non-homologous end joining (NHEJ) is the major pathway responsible for the repair of ionizing radiation (IR)-induced DNA double-strand breaks (DSB), and correspondingly regulates the cellular response to IR. Identification of NHEJ inhibitors could substantially enhance the tumor radiosensitivity and improve the therapeutic efficiency of radiotherapy. In this study, we demonstrated a screening for NHEJ inhibitors using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system and high-resolution melting (HRM) analysis. Because NHEJ is regarded as an error-prone mechanism, the NHEJ-mediated ligation of the site-specific DSB induced by Cas9 nuclease would eventually cause the mutation of the targeted sequence. Then, HRM analysis, a reliable and rapid assay for detecting sequence variation, was performed to evaluate the mutation efficiency of the targeted site. Validating analysis confirmed the NHEJ activities were positively correlated with the mutation frequencies. Next, an approved drug library containing 1,540 compounds was interrogated by using this screening strategy. Our results identified ouabain, a cardiotonic agent, and penfluridol, an antipsychotic agent, have the capacity to restrain NHEJ activity. Further experiments in vitro revealed the radiosensitizing effects of these compounds. Overall, we presented a cell-based screening for NHEJ inhibitors, which could promote the discovery of novel radiosensitizers. Mol Cancer Ther; 17(2); 419-31. ©2017 AACRSee all articles in this MCT Focus section, "Developmental Therapeutics in Radiation Oncology."

TIGAR knockdown radiosensitizes TrxR1-overexpressing glioma in vitro and in vivo via inhibiting Trx1 nuclear transport.

The up-regulation of thioredoxin reductase-1 (TrxR1) is detected in more than half of gliomas, which is significantly associated with increased malignancy grade and recurrence rate. The biological functions of NADPH-dependent TrxR1 are mainly associated with reduced thioredoxin-1 (Trx1) which plays critical roles in cellular redox signaling and tumour radio-resistance. Our previous work has proved that TP53 induced glycolysis and apoptosis regulator (TIGAR) knockdown could notably radiosensitize glioma cells. However, whether TrxR1-overexpressing glioma cells could be re-radiosensitized by TIGAR silence is still far from clear. In the present study, TrxR1 was stably over-expressed in U-87MG and T98G glioma cells. Both in vitro and in vivo data demonstrated that the radiosensitivity of glioma cells was considerably diminished by TrxR1 overexpression. TIGAR abrogation was able to radiosensitize TrxR1-overexpressing gliomas by inhibiting IR-induced Trx1 nuclear transport. Post-radiotherapy, TIGAR low-expression predicted significant longer survival time for animals suffering from TrxR1-overexpessing xenografts, which suggested that TIGAR abrogation might be a promising strategy for radiosensitizing TrxR1-overexpressing glial tumours.