[Translocation, Accumulation, and Comprehensive Risk Assessment of Heavy Metals in Soil-Crop Systems in an Old Industrial City, Shizuishan, Ningxia, Northwest China].

In order to explore the environmental geochemistry characteristics of heavy metals (HMs) in soil-crop systems in an old industrial city, the concentration and fraction of HMs in the paddy, wheat, and maize root soil and their seeds were detected and analyzed. Subsequently, statistical methods, risk assessment coding (RAC), the bio-enrichment coefficient factor (BCF), influence index of comprehensive quality (IICQ), and ArcGIS spatial interpolation were used to conduct the translocation, accumulation, and comprehensive risk assessment of HMs in soil-crop systems. The results showed that the average concentrations of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in root soil were ranked respectively as follows:12.56, 0.19, 63.48, 23.52, 0.038, 28.86, 21.68, and 69.47 mg·kg-1. HMs in root soil were accumulated to some extent in comparison with the soil background value in Ningxia, especially Cd and Hg, but did not exceed the soil environmental pollution screening value (GB 14618-2018). The average concentrations of the eight aforementioned elements in supporting crop seeds were 0.0149, 0.0112, 0.075, 6.7, 0.0015, 0.67, 0.0427, and 20.48 mg·kg-1 in turn. The over-limit ratio of As, Pb, and Cr in crop seeds was 4%, 3%, and 1%, respectively, relative to the national food safety standards (GB 2762-2017), whereas the other five elements were within the allowable range. In comparison to those in paddy and wheat, HMs hardly tended to translocate to maize seeds from root soil. According to the results of IICQ in soil-crop systems, the cultivated soil was in the state of slight sub-contamination regionally, and only 10% of sampling points showed slight (sub-)contamination-submoderate contamination, where we could replant maize to reduce HMs contamination risk.

[Threshold of Se-rich Soil Based on Available-Se and Influencing Factors of Available-Se].

Available selenium (Se) in soil was the predominant factor affecting the content of Se in crops. In order to reasonably delineate the Se-rich soil range and propose theoretical guidance for the cultivation of natural Se-rich crops in a region where the surface soils had a high level of available-Se and a low level of total-Se, 8814 samples in surface soil and 195 root-crop matching samples were collected in Shizuishan in northern Ningxia. On the basis of the main line of analysis of available-Se, the following research was conducted: by synthetically studying the total-Se and available-Se in surface soil and root soil, the morphology of Se in surface soil, as well as Se in crops, deep and coordinated analyses of content among total-Se, available-Se, and Se in root-crop matching samples were carried out, and the suitable threshold for Shizuishan was confirmed. A multiple regression model of available-Se was established to determine the main physical and chemical indexes affecting available-Se, which were expected to improve the Se enrichment rate of crops through the enhancement of available-Se. The results demonstrated that ω(Se) and ω(Seavailable)in the surface soil in Shizuishan were 0.26 mg·kg-1 and 12.85 µg·kg-1, respectively, and the characteristics of Se and available-Se in root-crop matching samples could represent those in surface soil. Thus, it was recommended to use 0.24 mg·kg-1 as the suitable threshold of Se-rich soil. The multiple regression model of available-Se showed that the increase in total-Se and soil elements affecting soil fertility could promote the enrichment of available-Se.

Initial CT-based radiomics nomogram for predicting in-hospital mortality in patients with traumatic brain injury: a multicenter development and validation study.

OBJECTIVE: To develop and validate a radiomic prediction model using initial noncontrast computed tomography (CT) at admission to predict in-hospital mortality in patients with traumatic brain injury (TBI). METHODS: A total of 379 TBI patients from three cohorts were categorized into training, internal validation, and external validation sets. After filtering the unstable features with the minimum redundancy maximum relevance approach, the CT-based radiomics signature was selected by using the least absolute shrinkage and selection operator (LASSO) approach. A personalized predictive nomogram incorporating the radiomic signature and clinical features was developed using a multivariate logistic model to predict in-hospital mortality in patients with TBI. The calibration, discrimination, and clinical usefulness of the radiomics signature and nomogram were evaluated. RESULTS: The radiomic signature consisting of 12 features had areas under the curve (AUCs) of 0.734, 0.716, and 0.706 in the prediction of in-hospital mortality in the internal and two external validation cohorts. The personalized predictive nomogram integrating the radiomic and clinical features demonstrated significant calibration and discrimination with AUCs of 0.843, 0.811, and 0.834 in the internal and two external validation cohorts. Based on decision curve analysis (DCA), both the radiomic features and nomogram were found to be clinically significant and useful. CONCLUSION: This predictive nomogram incorporating the CT-based radiomic signature and clinical features had maximum accuracy and played an optimized role in the early prediction of in-hospital mortality. The results of this study provide vital insights for the early warning of death in TBI patients.

GNG5 is an unfavourable independent prognostic indicator of gliomas.

Gliomas are the most common primary brain tumours, and glioblastomas (GBMs) are subgrouped into four distinct molecular subtypes. This study aimed to identify the potential gene related to glioma progression. Weighted gene co-expression network analysis (WGCNA) was used to explore the related gene. Correlation, ROC, survival and Cox regression analyses were performed. Blue module was strongly associated with WHO grade (r = .65, P = 1e-19). GNG5 in gliomas was overexpressed compared with normal samples and associated with clinicopathologic characteristics. GNG5 was frequent in Mesenchymal subtype and lowly expressed in Proneural subtype of GBMs. Survival and Cox regression analyses showed that glioma patients with GNG5 overexpression had shorter survival time, and GNG5 was an independent prognostic indicator of overall survival. Overall, GNG5 expression is closely associated with clinicopathologic characteristics and is an independent prognostic indicator for glioma patients, as well as a promising subtype-associated biomarker in molecular classification of gliomas.

Integrated Transcriptomic Analysis Reveals the Molecular Mechanism of Meningiomas by Weighted Gene Coexpression Network Analysis.

Meningiomas are the most common primary intracranial tumor in adults. However, to date, systemic coexpression analyses for meningiomas fail to explain its pathogenesis. The aim of the present study was to construct coexpression modules and identify potential biomarkers associated with meningioma progression. Weighted gene coexpression network analysis (WGCNA) was performed based on GSE43290, and module preservation was tested by GSE74385. Functional annotations were performed to analyze biological significance. Hub genes were selected for efficacy evaluations and correlation analyses using two independent cohorts. A total of 14 coexpression modules were identified, and module lightcyan was significantly associated with WHO grades. Functional enrichment analyses of module lightcyan were associated with tumor pathogenesis. The top 10 hub genes were extracted. Ten biomarkers, particularly AHCYL2, FGL2, and KCNMA1, were significantly related to grades and prognosis of meningioma. These findings not only construct coexpression modules leading to the better understanding of its pathogenesis but also provide potential biomarkers that represent specific on tumor grades and identify recurrence, predicting prognosis and progression of meningiomas.

Integrated Transcriptome Analyses and Experimental Verifications of Mesenchymal-Associated TNFRSF1A as a Diagnostic and Prognostic Biomarker in Gliomas.

Gliomas are the most prevalent malignant primary brain tumors with poor outcome, and four different molecular subtypes (Mesenchymal, Proneural, Neural, and Classical) are popularly applied in scientific researches and clinics of gliomas. Public databases contain an abundant genome-wide resource to explore the potential biomarker and molecular mechanisms using the informatics analysis. The aim of this study was to discover the potential biomarker and investigate its effect in gliomas. Weighted gene co-expression network analysis (WGCNA) was used to construct the co-expression modules and explore the biomarker among the dataset CGGA mRNAseq_693 carrying 693 glioma samples. Functional annotations, ROC, correlation, survival, univariate, and multivariate Cox regression analyses were implemented to investigate the functional effect in gliomas, and molecular experiments in vitro were performed to study the biological effect on glioma pathogenesis. The brown module was found to be strongly related to WHO grade of gliomas, and KEGG pathway analysis demonstrated that TNFRSF1A was enriched in MAPK signaling pathway and TNF signaling pathway. Overexpressed TNFRSF1A was strongly related to clinical features such as WHO grade, and functioned as an independent poor prognostic predictor of glioma patients. Notably, TNFRSF1A was preferentially upregulated in the Mesenchymal subtype gliomas (Mesenchymal-associated). Knockdown of TNFRSF1A inhibited proliferation and migration of glioma cell lines in vitro. Our findings provide a further understanding of the progression of gliomas, and Mesenchymal-associated TNFRSF1A might be a promising target of diagnosis, therapy, and prognosis of gliomas.

BMX activates Wnt/ß-catenin signaling pathway to promote cell proliferation and migration in breast cancer.

BACKGROUND: Breast cancer has become a dangerous killer for the female, which seriously threatened women's life, leading to huge pressures to society. The present study assessed the mechanism underlying the involvement of bone marrow tyrosine kinase on chromosome X (BMX) in breast cancer development. METHODS: The expression of BMX was examined by qPCR and immunohistochemistry. The effect of BMX on cell proliferation and migration was detected by Clone formation assay and Transwell assay. In vitro study, the correlation of BMX with Wnt/ß-catenin pathway was explored by western blot and TOP/FOP flash assay. RESULTS: In the present study, we found that BMX was up-regulated in breast cancer, which was associated with the tumor differentiation and TNM stage. Oncogenic BMX enhanced the ability of breast cancer cell proliferation and migration. Furthermore, BMX could up-regulate the protein expression levels of p-ß-catenin (Y142), p-ß-catenin(Y654) and inhibit the expression level of p-ß-catenin (S33/37), thus activating Wnt/ß-catenin pathway in MCF-7 and MDA-MB-231 cells. In addition, we revealed that BMX promoted GSK3ß phosphorylation, which suppressed the degradation of ß-catenin. CONCLUSIONS: In this study, we identified that BMX-activated Wnt/ß-catenin signaling pathway, playing an oncogenic role in breast cancer, suggesting that BMX could become a potential treatment target of breast cancer.

Identification of biomarkers and construction of a microRNA-mRNA regulatory network for ependymoma using integrated bioinformatics analysis.

Ependymomas (EPNs) are one of the most common types of malignant neuroepithelial tumors. In an effort to identify potential biomarkers involved in the pathogenesis of EPN, the mRNA expression profiles of the GSE25604, GSE50161, GSE66354, GSE74195 and GSE86574 datasets, in addition to the microRNA (miRNA/miR) expression profiles of GSE42657 were downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) and differentially expressed miRNAs (DEMs) between EPN and normal brain tissue samples were identified using the Limma package in R and GEO2R, respectively. Functional and pathway enrichment analyses were conducted using the Database for Annotation, Visualization and Integrated Discovery. A protein-protein interaction network was constructed using the Search Tool for Retrieval of Interacting Genes database, which was visualized using Cytoscape. The targeted genes of DEMs were predicted using miRWalk2.0 and a miRNA-mRNA regulatory network was constructed. Following analysis, a total of 948 DEGs and 129 DEMs were identified. Functional enrichment analysis revealed that 609 upregulated DEGs were significantly enriched in 'PI3K-Akt signaling pathway', while 339 downregulated DEGs were primarily involved in 'cell junction' and 'retrograde endocannabinoid signaling'. In addition, 6 hub genes [cyclin dependent kinase 1, CD44 molecule (Indian blood group) (CD44), proliferating cell nuclear antigen (PCNA), MYC, synaptotagmin 1 (SYT1) and kinesin family member 4A] and 6 crucial miRNAs [homo sapiens (hsa)-miR-34a-5p, hsa-miR-449a, hsa-miR-106a-5p, hsa-miR-124-3p, hsa-miR-128-3p and hsa-miR-330-3p] were identified as biomarkers and potential therapeutic targets for EPN. Furthermore, a microRNA-mRNA regulatory network was constructed to highlight the interactions between DEMs and their target DEGs; this included the hsa-miR-449a-SYT1, hsa-miR-34a-5p-SYT1, hsa-miR-330-3p-CD44 and hsa-miR-124-3p-PCNA pairs, whose expression levels were confirmed using reverse transcription-quantitative polymerase chain reaction. In conclusion, the present study may provide important data for the investigation of the molecular mechanisms of EPN pathogenesis.

Silencing lncRNA SNHG6 suppresses proliferation and invasion of breast cancer cells through miR-26a/VASP axis.

The important role of LncRNA in the development of breast cancer is attracting more and more attention. In the previous study, we found that the expression level of LncRNA SNHG6 in breast cancer tissues and cells was significantly increased, but its mechanism in the development of breast cancer was still unclear. Our study found that knockdown of SNHG6 significantly inhibited the proliferation, migration and invasion of breast cancer cells MCF-7 and MDA-MB-231 cells. Further study showed that knockdown of SNHG6 significantly inhibited the expression level of VASP. More importantly, SNHG6 and VASP both can bind directly to miR-26a, suggesting that SNHG6 could act as a ceRNA to sponge miR-26a, thereby promoting the expression of VASP, which leading to activated proliferation, migration and invasion of breast cancer cells. Taken together, this study revealed the important role of the SNHG6/miR-26a/VASP regulatory network in the development of breast cancer, and provided a reference for exploring new pathogenesis and biomarkers of breast cancer.

Examining the biomarkers and molecular mechanisms of medulloblastoma based on bioinformatics analysis.

Medulloblastoma (MB) is the most common malignant brain tumor in children. The aim of the present study was to predict biomarkers and reveal their potential molecular mechanisms in MB. The gene expression profiles of GSE35493, GSE50161, GSE74195 and GSE86574 were downloaded from the Gene Expression Omnibus (GEO) database. Using the Limma package in R, a total of 1,006 overlapped differentially expressed genes (DEGs) with the cut-off criteria of P<0.05 and |log2fold-change (FC)|>1 were identified between MB and normal samples, including 540 upregulated and 466 downregulated genes. Furthermore, the Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were also performed using the Database for Annotation, Visualization and Integrated Discovery (DAVID) online tool to analyze functional and pathway enrichment. The Search Tool for Retrieval of Interacting Genes database was subsequently used to construct a protein-protein interaction (PPI) network and the network was visualized in Cytoscape. The top 11 hub genes, including CDK1, CCNB1, CCNB2, PLK1, CDC20, MAD2L1, AURKB, CENPE, TOP2A, KIF2C and PCNA, were identified from the PPI network. The survival curves for hub genes in the dataset GSE85217 predicted the association between the genes and survival of patients with MB. The top 3 modules were identified by the Molecular Complex Detection plugin. The results indicated that the pathways of DEGs in module 1 were primarily enriched in cell cycle, progesterone-mediated oocyte maturation and oocyte meiosis; and the most significant functional pathways in modules 2 and 3 were primarily enriched in mismatch repair and ubiquitin-mediated proteolysis, respectively. These results may help elucidate the pathogenesis and design novel treatments for MB.

Silencing SATB1 overcomes temozolomide resistance by downregulating MGMT expression and upregulating SLC22A18 expression in human glioblastoma cells.

Glioblastoma multiforme (GBM) is the most common malignant tumor of the central nervous system and has a very poor prognosis. Currently, patients were treated by resection followed by radiotherapy plus concurrent temozolomide (TMZ) chemotherapy. However, many patients are resistant to TMZ-induced DNA damage because of upregulated expression of the DNA repair enzyme O6-methylguanine-DNA methyltransferase (MGMT). In this study, upregulation of SATB1 and MGMT, and downregulation of SLC22A18 resulted in acquisition of TMZ resistance in GBM U87 cells. Inactivation of special AT-rich sequence-binding protein 1 (SATB1) using short hairpin RNA (shRNA) downregulated MGMT expression and upregulated solute carrier family 22 member 18 (SLC22A18) expression in GBM cells. This suggested SATB1-mediated posttranscriptional regulation of the MGMT and SLC22A18 protein levels. Immunohistochemical analysis of malignant glioma specimens demonstrated a significant positive correlation between the levels of MGMT and SATB1, and a negative correlation between the levels of SLC22A18 and SATB1. Importantly, in recurrent, compared with the primary, lesions in 15 paired identical tumors, the SATB1 and MGMT protein levels were increased and the SLC22A18 levels were decreased. Finally, in TMZ-resistant GBM, SATB1 knockdown enhanced TMZ efficacy. Consequently, SATB1 inhibition might be a promising strategy combined with TMZ chemotherapy to treat TMZ-resistant GBM.

Upregulated IQUB promotes cell proliferation and migration via activating Akt/GSK3ß/ß-catenin signaling pathway in breast cancer.

Breast cancer was the highest incidence of tumor in women, which seriously threaten women's health. Our previous study found that the expression of IQUB (IQ motif and ubiquitin domain containing) was significantly increased in the development of breast cancer by transcriptome sequencing. However, there were no studies on the mechanism of IQUB in tumorigenesis. Further study showed that IQUB expression was significantly increased in breast cancer, which had a significantly positive correlation with pathological differentiation of breast cancer by tissue microarray analysis. Furthermore, we also discovered that IQUB overexpression could obviously promote the proliferation and migration of MCF-7 cells and increase the proportion of MCF-7 cells in S and G2/M phase in vitro study, while knockdown of IQUB caused inhibition of cell proliferation and migration in MDA-MB-231 cells and increased the proportion of MDA-MB-231 cells in G1 phase. Furthermore, IQUB overexpression or knockdown combined with treatment of Licl or MG-132 showed that IQUB activated Akt to promote GSK3ß phosphorylation, which in turn activated Wnt/ß-catenin signaling pathway in breast cancer cells. Taken together, these results indicated that upregulated IQUB promoted breast cancer cell proliferation and migration via activating Akt/GSK3ß/ß-catenin signaling pathway, which played an important part in the tumorigenesis and development of breast cancer.

Large animal models of traumatic brain injury.

Purpose/Aim: Animal models of traumatic brain injury (TBI) provide powerful tools to study TBI in a controlled, rigorous and cost-efficient manner. The mostly used animals in TBI studies so far are rodents. However, compared with rodents, large animals (e.g. swine, rabbit, sheep, ferret, etc.) show great advantages in modeling TBI due to the similarity of their brains to human brain. The aim of our review was to summarize the development and progress of common large animal TBI models in past 30 years. MATERIALS AND METHODS: Mixed published articles and books associated with large animal models of TBI were researched and summarized. RESULTS: We majorly sumed up current common large animal models of TBI, including discussion on the available research methodologies in previous studies, several potential therapies in large animal trials of TBI as well as advantages and disadvantages of these models. CONCLUSIONS: Large animal models of TBI play crucial role in determining the underlying mechanisms and screening putative therapeutic targets of TBI.

Betulinic acid induces apoptosis and ultrastructural changes in MDA-MB-231 breast cancer cells.

The aim of this study is to investigate the effects of betulinic acid (BA) on triple-negative breast cancer MDA-MB-231 cells and observe the ultrastructural changes. The concentration of BA required to induce apoptosis in MDA-MB-231 cells has been previously reported. In this study, a cell counting kit-8 proliferation assay was used to measure cell viability and the apoptosis rate. Western blotting was performed to observe the protein expression levels of Bcl-2. Cell morphology and changes in cell density were observed by microscopy. Electron microscopy revealed pyknotic nuclei as well as vacuoles. Collectively, our results showed the morphological mechanisms by which BA impairs the ultrastructure of MDA-MB-231 cells.

Sodium butyrate-induced apoptosis and ultrastructural changes in MCF-7 breast cancer cells.

This study investigated the effects of sodium butyrate (NaB) on Michigan Cancer Foundation-7 (MCF-7) breast cancer cells and analyzed the relevant mechanism. Here, we demonstrated that a certain concentration of NaB effectively induced MCF-7 cell apoptosis. Cell counting kit-8 (CCK-8) assay was used to detect cell viability and the apoptosis rate. Western blotting was used to detect changes in the Bcl-2 expression level. We observed cell shape changes with microscopy. Immunofluorescence revealed some apoptotic nuclei. Electron microscopy revealed thick nucleoli, chromatin margination, reduced mitochondria, and dramatic vacuoles. Collectively, our findings elucidated the morphological mechanism by which NaB changed the ultrastructure of MCF-7 cells.

Could a traumatic epidural hematoma on early computed tomography tell us about its future development? A multi-center retrospective study in China.

Our aim for this study was to quantitatively develop an early epidural hematoma (EDH) natural evolutionary curve and assess association of the most common radiological signs of initially nonsurgical supratentorial EDHs on early computed tomography (CT), in addition to their CT time for EDH enlargement. We retrospectively reviewed pertinent data of supratentorial EDH cases with CT ≤ 6 h postinjury (1997-2013) in three medical institutions in Shanghai. Cases involved were divided into six groups according to their initial CT time postinjury (≤ 1, 1-2, 2-3, 3-4, 4-5, and 5-6 h for groups 1 through 6, respectively). Time of initial CT, EDH-associated fractures, EDH volume, and EDH locations were the focus in the present study. A total of 797 eligible cases were included. The EDH growth curve showed that EDH reached 98.1% of its final stabilized size by volume in 5 ∼ 6 h postinjury. EDH volume and locations on initial CT was greatly associated with subsequent EDH increase ≥ 30 mL with EDH increase requiring surgery when CT time was added. Multi-variate analysis succeeded in determining two risk factors for EDH enlargement ≥ 30 mL and EDH enlargement requiring an operation for EDH cases with an early CT/EDH volume >10 mL on CT performed ≤ 2 h and EDH located at the temporal or temporoparietal region on CT ≤ 1 h post brain injury. Using recursive partitioning analysis, "high-risk" identification criteria were derived to predict EDH enlargement ≥ 30 mL with sensitivity of 90.5% (95% confidence interval [CI], 77.9-96.2), specificity of 60.1% (95% CI, 54.3-65.7), and EDH enlargement requiring surgery with sensitivity of 100.0% (95% CI, 89.9-100.0), and specificity of 59.9% (95% CI, 54.1-65.4). A redo-CT 5 ∼ 6 h post impact for cases at high risk is recommended.

Where are we in the modelling of traumatic brain injury? Models complicated by secondary brain insults.

BACKGROUND: Traumatic brain injury (TBI) contributes to a substantial number of deaths and cases of disability. Despite well-established experimental models and years of carefully conducted research, a clinical therapeutic breakthrough in TBI has lagged. This may be due, in part, to the discrepancies between commonly used experimental models and clinical scenarios. METHOD: Secondary insults, such as hypotension and hypoxemia, have been well demonstrated as powerful determinants of outcomes from TBI. Despite the frequency of secondary insults in patients with TBI, they are rarely incorporated into most existing models of TBI. This review focuses on the combined injury models, especially coupled with systemic secondary insults, and aims to provide a new view to guiding future research endeavors in this field. RESULTS: A growing number of experimental models of TBI complicated by certain secondary insult have been gradually introduced and characterized. Correspondingly, the pathophysiological changes following combined injuries and the interactive effects of primary injury with secondary insults can be studied more in-depth. CONCLUSION: A more complete understanding of the interactions between the injured brain and secondary insults represents a potentially fruitful avenue that may increase the likelihood of developing effective therapies. Experimental models of TBI should not only attempt to model the focal or diffuse changes resulting from external forces, but also integrate, when appropriate, secondary insults reminiscent of human situations.

Inhibition of human glioma U251 cells growth in vitro and in vivo by hydroxyapatite nanoparticle-assisted delivery of short hairpin RNAs against SATB1.

Special AT-rich sequence-binding protein-1 (SATB1) has been reported to be over-expressed in many human tumors and knockdown of SATB1 can inhibit tumor growth. The present study was designed to determine the role of SATB1 in the growth of human glioma U251 cells using the plasmid-based SATB1 short hairpin RNA (shRNA) delivered by hydroxyapatite nanoparticles in vitro and in vivo. The in vitro growth, invasion and angiogenesis assays of human glioma U251 cells were done. U251 cells tumor blocks were transplanted into the nude mice. CaCl2-modified hydroxyapatite nanoparticles carrying shRNA-SATB1 plasmids were injected into the tumors. The apoptosis of the tumor U251 cells was examined with TUNEL assay and flow cytometer (FCM). The tumor growth and immunohistochemistry were measured. The expression level of SATB1 mRNA was investigated by RT-PCR. The expression levels of SATB1, Cyclin D1, MMP-2, VEGF, Bax and Caspase-9 protein were determined by western blot analysis. The results showed that hydroxyapatite nanoparticles-delivered shRNA-SATB1 could significantly inhibit the growth, invasion and angiogenesis of U251 cells in vitro and the growth of U251 cells in vivo. FCM results showed that Nano HAP-shRNA-SATB1-induced apoptosis (up to 67.8 %). SATB1 expression was strongly down-regulated in the tumor U251 cells. Cyclin D1, MMP-2 and VEGF were also down-regulated in the tumor tissues that also displayed significant increased in Bax expression and Caspase-9 activity. These results show that Nano HAP-shRNA-SATB1 can inhibit the growth of human glioma U251 cells in vitro and in vivo, and hydroxyapatite nanoparticles can be used for the in vitro and in vivo delivery of plasmid-based shRNAs into U251 cells.

In vitro and in vivo radiosensitization induced by hydroxyapatite nanoparticles.

BACKGROUND: Previous study showed that hydroxyapatite nanoparticles (nano-HAPs) inhibited glioma growth in vitro and in vivo; and in a drug combination, they could reduce adverse reactions. We investigated the possible enhancement of radiosensitivity induced by nano-HAPs. METHODS: In vitro radiosensitization of nano-HAPs was measured using a clonogenic survival assay in human glioblastoma U251 and breast tumor brain metastatic tumor MDA-MB-231BR cells. DNA damage and repair were measured using γH2AX foci, and mitotic catastrophe was determined by immunostaining. The effect of nano-HAPs on in vivo tumor radiosensitivity was investigated in a subcutaneous and an orthotopic model. RESULTS: Nano-HAPs enhanced each cell line's radiosensitivity when the exposure was 1 h before irradiation, and they had no significant effect on irradiation-induced apoptosis or on the activation of the G2 cell cycle checkpoint. The number of γH2AX foci per cell was significantly large at 24 h after the combination modality of nano-HAPs + irradiation compared with single treatments. Mitotic catastrophe was also significantly increased at an interval of 72 h in tumor cells receiving the combined modality compared with the individual treatments. In a subcutaneous model, nano-HAPs caused a larger than additive increase in tumor growth delay. In an orthotopic model, nano-HAPs significantly reduced tumor growth and extended the prolongation of survival induced by irradiation. CONCLUSIONS: These results show that nano-HAPs can enhance the radiosensitivity of tumor cells in vitro and in vivo through the inhibition of DNA repair, resulting in an increase in mitotic catastrophe.

Predictive value of the SLC22A18 protein expression in glioblastoma patients receiving temozolomide therapy.

BACKGROUND: Our previous study showed that SLC22A18 downregulation and promoter methylation were associated with the development and progression of glioma and the elevated expression of SLC22A18 was found to increase the sensitivity of glioma U251 cells to the anticancer drug 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). In this study, we investigated the predictive value of SLC22A18 promoter methylation and protein expression in glioblastoma multiforme (GBM) patients receiving temozolomide (TMZ) therapy. PATIENTS AND METHODS: SLC22A18 promoter methylation and protein expression were examined by methylation-specific polymerase chain reaction (MSP) and Western blotting respectively, then we compared SLC22A18 promoter methylation and protein expression in tumor cell explants in regard to prediction of TMZ response and survival time of 86 GBM patients. RESULTS: SLC22A18 promoter methylation was detected in 61 of 86 (71%) samples, whereas 36 of 86 (42%) cases were scored positive for SLC22A18 protein expression. Overall SLC22A18 promoter methylation was significantly related to SLC22A18 protein expression, but a subgroup of cases did not follow this association. Multivariate Cox regression analysis indicated that SLC22A18 protein expression, but not promoter methylation, was significantly correlated with TMZ therapy. SLC22A18 protein expression predicted a significantly shorter overall survival in 51 patients receiving TMZ therapy, whereas no differences in overall survival were observed in 35 patients without TMZ therapy. CONCLUSIONS: These results show that lack of SLC22A18 protein expression is superior to promoter methylation as a predictive tumor biomarker in GBM patients receiving temozolomide therapy.