MZF1 mediates oncogene-induced senescence by promoting the transcription of p16INK4A.

Oncogene induced senescence is a tumor suppressing defense mechanism, in which the cell cycle-dependent protein kinase (CDK) inhibitor p16INK4A (encoded by the CDKN2A gene) plays a key role. We previously reported that a transcriptional co-activator chromodomain helicase DNA binding protein 7 (CHD7) mediates oncogenic ras-induced senescence by inducing transcription of the p16INK4A gene. In the current study, we identified myeloid zinc finger 1 (MZF1) as the transcriptional factor that recruits CHD7 to the p16INK4A promoter, where it mediates oncogenic ras-induced p16INK4A transcription and senescence through CHD7, in primary human cells from multiple origins. Moreover, the expression of MZF1 is induced by oncogenic ras in senescent cells through the c-Jun and Ets1 transcriptional factors upon their activation by the Ras-Raf-1-MEK-ERK signaling pathway. In non-small cell lung cancer (NSCLC) and pancreatic adenocarcinoma (PAAD) where activating ras mutations occur frequently, reduced MZF1 expression is observed in tumors, as compared to corresponding normal tissues, and correlates with poor patient survival. Analysis of single cell RNA-sequencing data from PAAD patients revealed that among the tumor cells with normal RB expression levels, those with reduced levels of MZF1 are more likely to express lower p16INK4A levels. These findings have identified novel signaling components in the pathway that mediates induction of the p16INK4A tumor suppressor and the senescence response, and suggested that MZF1 is a potential tumor suppressor in at least some cancer types, the loss of which contributes to the inactivation of the p16INK4A/RB pathway and disruption of senescence in tumor cells with intact RB.

[Implications of EET in renal ischemia/reperfusion by regulating NLRP3 expression and pyroptosis].

Objective: To investigate the mechanism of epoxyeicosatrienoic acids (EET) on renal ischemia/reperfusion (I/R). Methods: Thirty 10-week male C57BL6 mice were randomly divided into five groups: sham goup, I/R group, I/R with EET group, I/R with toll-like receptor 4 (TLR4) inhibitor (TAK242) group, I/R with EET and TAK242 group. Blood urea nitrogen (BUN) and serum creatinine (Scr) as well as renal pathological changes were observed 24 h after reperfusion. The protein expression of NOD-like receptor pyrin domain containing 3 (NLRP3), cysteinyl aspartate specific proteinase 1 (caspase-1), interleukin-1ß (IL-1ß), TLR4 and myeloid differentiation factor 88 (MyD88) were evaluated using Western blot. Results: Severe renal tubular epithelial cell injury and decreased renal function [BUN:(10.37±0.53) vs (6.70±0.82)mmol/L, t=9.17, P<0.001; Scr: (83.67±3.88) vs (32.50±3.51)µmol/L, t=23.96, P<0.001] occurred in I/R group. Compared to the sham group, the relative expression of NLRP3 (1.54±0.10 vs 0.71±0.05, t=13.14, P<0.001), caspase-1 (2.35±0.05 vs 0.62±0.02, t=73.77, P<0.001), IL-1ß (3.11±0.11 vs 1.26±0.05, t=35.97, P<0.001), TLR4 (1.58±0.03 vs 0.39±0.01, t=86.00, P<0.001), MyD88 (0.94±0.02 vs 0.26±0.01, t=72.61, P<0.001) were significantly increased. Mice pretreated with EET analog featured lower kidney damage and diminished levels of above proteins than I/R group (all P<0.001). Besides, the co-administration of TAK242 and EET analog could even markedly reduced the expression levels of each proteins than those in I/R group and I/R with EET group (all P<0.001). Conclusion: EET exerts a protective effect on attenuating renal I/R injury possibly through inhibiting TLR4 pathway to regulate the activation of NLRP3-induced pyroptosis.

Regorafenib and ginsenoside combination therapy: inhibition of HepG2 cell growth through modulating survivin and caspase-3 gene expression.

BACKGROUND: This work aimed to investigate the inhibitory effect of regorafenib in combination with ginsenoside on the growth of HepG2 liver cancer cells. METHODS: HepG2 liver cancer cells were divided into blank control group, regorafenib single-drug group, ginsenoside single-drug group, and regorafenib/ginsenoside combination group. Cells in the regorafenib single-drug group were treated with regorafenib at 0.25 mg/L, 0.5 mg/L, and 1 mg/L, respectively, while cells in the ginsenoside single-drug group were treated with ginsenoside at 5.0 mg/L, 10.0 mg/L, and 20.0 mg/L, respectively. HepG2 cell proliferation, expression of survivin mRNA, and the apoptotic effector caspase-3 in HepG2 liver cancer cells were assessed. RESULTS: An inhibitory effect on the growth of HepG2 liver cancer cells was observed for both the single-drug therapies and the combination therapy. The synergistic inhibitory effect presented by the combination therapy was dependent on the gradient concentration and treatment time. RT-qPCR results showed that both regorafenib and ginsenoside significantly reduced the expression of survivin mRNA in HepG2 liver cancer cells and the expression level of survivin mRNA in the regorafenib/ginsenoside combination group was much lower than those in the regorafenib single-drug group and ginsenoside single-drug group. The two drugs demonstrated synergistic inhibitory effect when used in combination. CONCLUSIONS: The findings in this study offered a theoretical insight into clinical use of regorafenib and ginsenoside for treatment of liver cancer.

MiR-1298 expression correlates with prognosis and inhibits cell proliferation and invasion of gastric cancer.

OBJECTIVE: To explore the association between miR-1298 expression and clinicopathological factors, prognosis of gastric cancer (GC) patients and biological functions underlying the GC progression. PATIENTS AND METHODS: Expression of miR-1298 was examined by qRT-PCR in GC tissues and cells, the adjacent normal tissues and normal gastric cell line GES-1 cells were used as controls. Association of disease-free survival (DFS) and overall survival (OS) time with miR-1298 expression was analyzed by Kaplan-Meier analysis and log-rank test. Univariate and multivariate analysis were also performed to analyze relative prognostic risk factors of GC patients. Cell proliferation and invasion assays were used to examine cell proliferation and invasion capacities in vitro. The relative protein expression was analyzed by Western blot analysis. RESULTS: MiR-1298 expression was lower in GC tissues and cells, compared to adjacent normal tissues and GES-1 cells, respectively. Lower miR-1298 expression levels were associated with lymph node metastasis and TNM stage. Kaplan-Meier analysis showed that lower miR-1298 expression predicted poor DFS and OS of GC patients. Furthermore, we demonstrated that lymph node metastasis, TNM stage, and lower miR-1298 expression were independent risk factors for DFS and OS in GC patients. In vitro, miR-1298 overexpression inhibited cell proliferation and invasion abilities. Additionally, our results revealed that miR-1298 overexpression suppressed PI3K/AKT signaling pathway in GC cells. CONCLUSIONS: Our evidence indicated that miR-1298 may provide a specifically promising target for therapy of GC patients.

Atmospheric gas-to-particle conversion: why NPF events are observed in megacities?

In terms of the global aerosol particle number load, atmospheric new particle formation (NPF) dominates over primary emissions. The key for quantifying the importance of atmospheric NPF is to understand how gas-to-particle conversion (GTP) takes place at sizes below a few nanometers in particle diameter in different environments, and how this nano-GTP affects the survival of small clusters into larger sizes. The survival probability of growing clusters is tied closely to the competition between their growth and scavenging by pre-existing aerosol particles, and the key parameter in this respect is the ratio between the condensation sink (CS) and the cluster growth rate (GR). Here we define their ratio as a dimensionless survival parameter, P, as P = (CS/10-4 s-1)/(GR/nm h-1). Theoretical arguments and observations in clean and moderately-polluted conditions indicate that P needs to be smaller than about 50 for a notable NPF to take place. However, the existing literature shows that in China, NPF occurs frequently in megacities such as in Beijing, Nanjing and Shanghai, and our analysis shows that the calculated values of P are even larger than 200 in these cases. By combining direct observations and conceptual modelling, we explore the variability of the survival parameter P in different environments and probe the reasons for NPF occurrence under highly-polluted conditions.

Genome-wide analysis of TCP family in tobacco.

The TCP family is a transcription factor family, members of which are extensively involved in plant growth and development as well as in signal transduction in the response against many physiological and biochemical stimuli. In the present study, 61 TCP genes were identified in tobacco (Nicotiana tabacum) genome. Bioinformatic methods were employed for predicting and analyzing the gene structure, gene expression, phylogenetic analysis, and conserved domains of TCP proteins in tobacco. The 61 NtTCP genes were divided into three diverse groups, based on the division of TCP genes in tomato and Arabidopsis, and the results of the conserved domain and sequence analyses further confirmed the classification of the NtTCP genes. The expression pattern of NtTCP also demonstrated that majority of these genes play important roles in all the tissues, while some special genes exercise their functions only in specific tissues. In brief, the comprehensive and thorough study of the TCP family in other plants provides sufficient resources for studying the structure and functions of TCPs in tobacco.

Enhanced air pollution via aerosol-boundary layer feedback in China.

Severe air pollution episodes have been frequent in China during the recent years. While high emissions are the primary reason for increasing pollutant concentrations, the ultimate cause for the most severe pollution episodes has remained unclear. Here we show that a high concentration of particulate matter (PM) will enhance the stability of an urban boundary layer, which in turn decreases the boundary layer height and consequently cause further increases in PM concentrations. We estimate the strength of this positive feedback mechanism by combining a new theoretical framework with ambient observations. We show that the feedback remains moderate at fine PM concentrations lower than about 200 µg m(-3), but that it becomes increasingly effective at higher PM loadings resulting from the combined effect of high surface PM emissions and massive secondary PM production within the boundary layer. Our analysis explains why air pollution episodes are particularly serious and severe in megacities and during the days when synoptic weather conditions stay constant.

Homology-based analysis of the GRAS gene family in tobacco.

Members of the GRAS gene family are important transcriptional regulators. In this study, 21 GRAS genes were identified from tobacco, and were classified into eight subgroups according to the classification of Arabidopsis thaliana. Here, we provide a preliminary overview of this gene family in tobacco, describing the gene structure, gene expression, protein motif organization, phylogenetic analysis, and comparative analysis in tobacco, Arabidopsis, and rice. Using the sequences of 21 GRAS genes in Arabidopsis to search against the American tobacco genome database, 21 homologous GRAS genes in tobacco were identified. Sequence analysis indicates that these GRAS proteins have five conserved domains, which is consistent with their counterparts in other plants. Phylogenetic analyses divided the GRAS gene family into eight subgroups, each of which has distinct conserved domains and biological functions. Furthermore, the expression pattern of these 21 GRAS genes reveals that most are expressed in all six tissues studied; however, some have tissue specificity. Taken together, this comprehensive analysis will provide a rich resource to assist in the study of GRAS protein functions in tobacco.

Computed tomography-guided iodine-125 interstitial implantation as an alternative treatment option for lung cancer.

PURPOSE: The aim was to evaluate the safety, feasibility and efficacy of computed tomography (CT)-guided percutaneous interstitial brachytherapy using radioactive iodine-125 ( 125 I) seeds for the treatment of lung cancer. MATERIALS AND METHODS: Included in this study were 45 male and 35 female patients aged 52-85 years (mean 72-year) who were diagnosed with lung cancer. Of the 80 cases of lung cancer, 38 were pathologically confirmed as squamous cell carcinoma, 29 as adenocarcinoma, 2 as small cell lung cancer, and 11 as metastatic lung cancer. Percutaneous interstitial implantation of radioactive 125 I seeds was performed under CT guidance. The treatment planning system was used to reconstruct three-dimensional images of the tumor to determine the quantity and distribution of 125 I seeds to be implanted. Under CT guidance, 125 I seeds were embedded into the tumor, with the matched peripheral dose set at 100-130 Gy. Follow-up CT scan was done in 2-month to explore the treatment efficacy. RESULTS: The procedure was successful in all patients. No major procedure-associated death occurred. The duration of follow-up was 6-month. Complete response (CR) was seen in 38 cases (47.5%), partial response (PR) in 27 cases (33.75%), stable disease (SD) in 10 cases (12.5%), and progressive disease in 5 cases (6.25%), with a local control rate (CR + PR + SD) of 93.75%. The 2-, 4- and 6-month overall response rate (CR + PR) was 78%, 83% and 81%, respectively. CONCLUSION: Implantation of CT-guided 125 I seeds is a safe and effective alternative option for the treatment of lung cancer.

Homology-based cloning and expression analysis of Rf genes encoding PPR-containing proteins in tobacco.

As a model plant, mechanisms of the cytoplasmic male sterility/restoration of fertility (CMS/Rf) system in tobacco are seldom studied. Using Rf gene sequences from other Solanaceae plants and the draft genome of Nicotiana benthamiana, degenerate primers were designed to amplify the cDNA pool of N. tomentosiformis. In total, six possible Rf sequences were identified, two of which contained base-deletion mutations. The other four were intact open reading frames, of which NtomPPR5 harbored a 3-pentatricopeptide repeat (PPR) motif deletion. Structure analysis revealed that they all encoded a PPR-containing protein with putative mitochondrial targeting signals at their N-terminus, and they all belong to the P subfamily. Phylogenetic analysis showed that all of the Rf-coding PPRs clustered together, and recent duplication events might have occurred in tobacco after the divergence of the species. Quantitative reverse transcription polymerase chain reaction analysis demonstrated that the NtomRfs were expressed in all tissues of N. tomentosiformis and (CMS) K326, although the expression levels varied with gene, organ, and developmental stage. Furthermore, the expression levels of Rf sequences in K326 were lower than those in CMS K326. The molecular basis of the CMS/Rf system in tobacco requires further investigation.

Electrocatalytic degradation kinetic of 4-chlorophenol by the Pd/C gas-diffusion electrode system.

A Pd/C gas-diffusion cathode which generated H2O2 through a two-electron reduction process of fed oxygen molecule was used to degrade 4-chlorophenol in an undivided electrolysis device. The kinetics of 4-chlorophenol degradation has been investigated by the electrochemical oxidation processes. By inspecting the relationship between the rate constants (k) and influencing factors, using first-order kinetics to describe the electrochemical oxidation process of 4-chlorophenol, a kinetic model of 4-chlorophenol degradation process was proposed to calculate the 4-chlorophenol effluent concentration: C = C0 exp( -3:76 × 10(-6) C(-0.5)0 J(2) M(-0.7) Q(0.17) Dt). It was found that the electrocatalytic degradation rate of 4-chlorophenol was affected by current density, electrode distance, air-feeding rate, electrolyte concentration and initial 4-chlorophenol concentration. The kinetics obtained from the experiments under corresponding electrochemical conditions could provide an accurate estimation of 4-chlorophenol effluent concentration and lead to better design of the electrochemical reactor.

OxLDL-targeted iron oxide nanoparticles for in vivo MRI detection of perivascular carotid collar induced atherosclerotic lesions in ApoE-deficient mice.

Atherosclerotic disease is a leading cause of morbidity and mortality in developed countries, and oxidized LDL (OxLDL) plays a key role in the formation, rupture, and subsequent thrombus formation in atherosclerotic plaques. In the current study, anti-mouse OxLDL polyclonal antibody and nonspecific IgG antibody were conjugated to polyethylene glycol-coated ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles, and a carotid perivascular collar model in apolipoprotein E-deficient mice was imaged at 7.0 Tesla MRI before contrast administration and at 8 h and 24 h after injection of 30 mg Fe/kg. The results showed MRI signal loss in the carotid atherosclerotic lesions after administration of targeted anti-OxLDL-USPIO at 8 h and 24 h, which is consistent with the presence of the nanoparticles in the lesions. Immunohistochemistry confirmed the colocalization of the OxLDL/macrophages and iron oxide nanoparticles. The nonspecific IgG-USPIO, unconjugated USPIO nanoparticles, and competitive inhibition groups had limited signal changes (p < 0.05). This report shows that anti-OxLDL-USPIO nanoparticles can be used to directly detect OxLDL and image atherosclerotic lesions within 24 h of nanoparticle administration and suggests a strategy for the therapeutic evaluation of atherosclerotic plaques in vivo.

SU-E-T-493: Accelerated Monte Carlo Methods for Photon Dosimetry Using a Dual-GPU System and CUDA.

PURPOSE: To develop a Graphics Processing Unit (GPU) based Monte Carlo (MC) code that accelerates dose calculations on a dual-GPU system. METHODS: We simulated a clinical case of prostate cancer treatment. A voxelized abdomen phantom derived from 120 CT slices was used containing 218×126×60 voxels, and a GE LightSpeed 16-MDCT scanner was modeled. A CPU version of the MC code was first developed in C++ and tested on Intel Xeon X5660 2.8GHz CPU, then it was translated into GPU version using CUDA C 4.1 and run on a dual Tesla m2 090 GPU system. The code was featured with automatic assignment of simulation task to multiple GPUs, as well as accurate calculation of energy- and material- dependent cross-sections. RESULTS: Double-precision floating point format was used for accuracy. Doses to the rectum, prostate, bladder and femoral heads were calculated. When running on a single GPU, the MC GPU code was found to be ×19 times faster than the CPU code and ×42 times faster than MCNPX. These speedup factors were doubled on the dual-GPU system. The dose Result was benchmarked against MCNPX and a maximum difference of 1% was observed when the relative error is kept below 0.1%. CONCLUSIONS: A GPU-based MC code was developed for dose calculations using detailed patient and CT scanner models. Efficiency and accuracy were both guaranteed in this code. Scalability of the code was confirmed on the dual-GPU system.

Antibody binding to neuronal surface in Sydenham chorea, but not in PANDAS or Tourette syndrome.

OBJECTIVE: To test the hypothesis that Sydenham chorea (SC) immunoglobulin G (IgG) autoantibodies bind to specific neuronal surface proteins, whereas IgG from patients with pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection (PANDAS) or Tourette syndrome (TS) do not bind to neuronal surface proteins. METHODS: We used live differentiated SH-SY5Y cells, which have neuronal and dopaminergic characteristics. Using flow cytometry, we measured serum IgG cell surface binding in patients with SC (n = 11), PANDAS (n = 12), and TS (n = 11), and compared the findings to healthy controls (n = 11) and other neurologic controls (n = 11). In order to determine the specificity of binding to neuronal antigens, we also used a non-neuronal cell line, HEK 293. RESULTS: The mean IgG cell surface binding was significantly higher in the SC group compared to all other groups (p < 0.001). By contrast, there was no difference between the PANDAS or TS groups and the controls. Using the non-neuronal HEK-293 cells, there was no significant difference in IgG cell surface binding between any groups. CONCLUSIONS: Serum autoantibodies that bind to neuronal cell surface antigens are present in SC, but not in PANDAS or TS. These findings strengthen the hypothesis that SC is due to a pathogenic autoantibody, but weaken the autoantibody hypothesis in PANDAS and TS.

Lysyl oxidase (lox) gene deficiency affects osteoblastic phenotype.

Lysyl oxidase (LOX) catalyzes cross-linking of elastin and collagen, which is essential for the structural integrity and function of bone tissue. The present study examined the role of Lox gene deficiency for the osteoblast phenotype in primary calvarial osteoblasts from E18.5 Lox knockout (Lox ( -/- )) and wild type (wt) (C57BL/6) mice. Next to Lox gene depletion, mRNA expression of Lox isoforms, LOXL1-4, was significantly downregulated in Lox ( -/- ) bone tissue. A significant decrease of DNA synthesis of Lox ( -/- ) osteoblasts compared to wt was found. Early stages of osteoblastic apoptosis studied by annexin-V binding as well as later stages of DNA fragmentation were not affected. However, mineral nodule formation and osteoblastic differentiation were markedly decreased, as revealed by significant downregulation of osteoblastic markers, type I collagen, bone sialoprotein, and Runx2/Cbfa1.

The role of MyD88 and TLR4 in the LPS-mimetic activity of Taxol.

Taxol can mimic bacterial lipopolysaccharide (LPS) by activating mouse macrophages in a cell cycle-independent, LPS antagonist-inhibitable manner. Macrophages from C3H/HeJ mice, which have a spontaneous mutation in Toll-like receptor 4 (TLR4), are hyporesponsive to both LPS and Taxol, suggesting that LPS and Taxol may share a signaling pathway involving TLR4. To determine whether TLR4 and its interacting adaptor molecule MyD88 are necessary for Taxol's LPS mimetic actions, we examined Taxol responses of primary macrophages from genetically defective mice lacking either TLR4 (C57BL/10ScNCr) or MyD88 (MyD88 knockout). When stimulated with Taxol, macrophages from wild-type mice responded robustly by secreting both TNF and NO, while macrophages from either TLR4-deficient C57BL/10ScNCr mice or MyD88 knockout mice produced only minimal amounts of TNF and NO. Taxol-induced NF-kappa B-driven luciferase activity was reduced after transfection of RAW 264.7 macrophages with a dominant negative version of mouse MyD88. Taxol-induced microtubule-associated protein kinase (MAPK) activation and NF-kappa B nuclear translocation were absent from TLR4-null macrophages, but were preserved in MyD88 knockout macrophages with a slight delay in kinetics. Neither Taxol-induced NF-kappa B activation, nor I kappa B degradation was affected by the presence of phosphatidylinositol 3-kinase inhibitors. These results suggest that Taxol and LPS not only share a TLR4/MyD88-dependent pathway in generating inflammatory mediators, but also share a TLR4-dependent/MyD88-independent pathway leading to activation of MAPK and NF-kappa B.

[Correlation between enhanced anoxic tolerance induced by hypoxic preconditioning and the stability of mitochondrial membrane potential in cultured hypothalamic cells].

The relationship between enhanced anoxic tolerance induced by hypoxic preconditioning and mitochondrial membrane potential (MMP) was studied in cultured hypothalamic cells. Dynamic changes in MMP were monitored by confocal laser scanning microscopy and expression of B-cell lymphoma/leukemia-2 (bcl-2) was examined by flowcytometry. Hypoxic preconditioning increased the cell survival rate and decreased the lactate dehydrogenase leakage under acute anoxia, in addition to maintaining MMP at a relatively higher level and inducing bcl-2 overexpression during anoxia. The results suggest that hypoxic preconditioning can enhance the tolerance of hypothalamic cells to anoxia, and the underlying mechanism may be related to increased stability of MMP. Overexpression of bcl-2 induced by hypoxic preconditioning may play a role in sustaining the stability of MMP.

[The pathology and DNA quantitative study of renal clear cell carcinoma in children].

OBJECTIVE: To investigate the pathological features of renal clear cell carcinoma (RCCC) in children and its relationship to the DNA content of cancer cells and DNA ploidy. METHODS: The pathologic morphology of 4 cases of RCCC in children were observed. Using image analysis instruments the quantity of tumor cell DNA was measured. RESULTS: The cytoplasm of the tumor cells were clear in all four cases. Papillary structures were present in these tumors, of which the papillary structure in two cases was over 50%, three cases had small calcified bodies with prominent bleeding and necrosis. Around tumor the glomerular and tubular of kidney always is normal the average DNA index was 1.31. They presented diploidy, high diploidy or subtetraploidy. CONCLUSIONS: The specific features of most RCCC in children are clear cytoplasm, most contain papillary structures, calcified bodies, often with bleeding and necrosis. Around tumor the glomerular and tubular of kidney is always normal. The DNA contents of cancer cells present diploidy, high diploidy or subtetraploidy.