Anisomycin induces apoptosis of glucocorticoid resistant acute lymphoblastic leukemia CEM-C1 cells via activation of mitogen-activated protein kinases p38 and JNK

Glucocorticoids (GCs) resistance is frequently encountered in children with acute lymphoblastic leukemia (ALL), especially in T-ALL, which usually results in failure of treatment. To find new agent to overcome GC resistance of ALL is an urgent problem. Here we investigated potential effect of anisomycin on GC-resistant T-ALL CEM-C1 cells and explored involved molecular mechanisms. Dramatic growth inhibition and apoptosis in GC resistant CEM-C1 cells and GC-sensitive CEM-C7 cells induced by anisomycin were observed, which presented in a concentration- and time-dependent manner. Correspondingly, anisomycin induced cleaved caspase-3 and up-regulation of pro-apoptotic proteins (BimEL and Bad), meanwhile down-regulation of anti-apoptotic proteins (Mcl-1 and Bcl-2), both in a dose- and time-dependent manner in GC resistant CEM-C1 cells. Anisomycin also induced cell cycle arrest at G0/G1 phase in CEM-C1 cells through increasing expressions of p21 and p27, and attenuating the expression of cyclinA. The rapid up-regulation of phosphorylated mitogen-activated protein kinases (MAPKs) p38 and Jun N-terminal kinase (JNK) were observed after CEM-C1 cells were incubated with anisomycin. The activation of p38 and JNK could be blocked by respective inhibitors (SB203580 for p38 and SP600125 for JNK) accompanied with the inhibition of apoptosis and changes of apoptosis associated proteins in CEM-C1 cells. These results suggested that anisomycin induced apoptosis of CEM-C1 cells via activation of p38 and JNK, and might be an attractive new agent for treatment of GC-resistant ALL.

Fiber-optic two-photon optogenetic stimulation

Optogenetic stimulation of genetically targeted cells is proving to be a powerful tool in the study of cellular systems, both in vitro and in vivo. However, most opsins are activated in the visible spectrum, where significant absorption and scattering of stimulating light occurs, leading to low penetration depth and less precise stimulation. Since we first (to the best of our knowledge) demonstrated two-photon optogenetic stimulation (TPOS), it has gained considerable interest in the probing of cellular circuitry by precise spatial modulation. However, all existing methods use microscope objectives and complex scanning beam geometries. Here, we report a nonscanning method based on multimode fiber to accomplish fiber-optic TPOS of cells.

Etifoxine promotes glial‑derived neurotrophic factor‑induced neurite outgrowth in PC12 cells

Nerve regeneration and functional recovery are major issues following nerve tissue damage. Etifoxine is currently under investigation as a therapeutic strategy for promoting neuroprotection, accelerating axonal regeneration and modulating inflammation. In the present study, a well‑defined PC12 cell model was used to explore the underlying mechanism of etifoxine‑stimulated neurite outgrowth. Etifoxine was found to promote glial‑derived growth factor (GDNF)‑induced neurite outgrowth in PC12 cells. Average axon length increased from 50.29±9.73 to 22.46±5.62 µm with the use of etifoxine. However, blockage of GDNF downstream signaling was found to lead to the loss of this phenomenon. The average axon length of the etifoxine group reduces to a normal level after the blockage of the GDNF family receptor α1 (GFRα1) and receptor tyrosine kinase (RETS) receptors (27.46±3.59 vs. 22.46±5.62 µm and 25.31±3.68 µm vs. 22.46±5.62 µm, respectively, p>0.05). In addition, etifoxine markedly increased GDNF mRNA and protein expression (1.55‑ and 1.36-fold, respectively). However, blockage was not found to downregulate GDNF expression. The results of the current study demonstrated that etifoxine stimulated neurite outgrowth via GDNF, indicating that GDNF represents a key molecule in etifoxine‑stimulated neurite outgrowth in PC12 cells.

[A trail of three-dimensional visualization technique to observe intraneural microvessels of sciatic nerves in Sprague Dawley rats]

OBJECTIVE

To investigate the feasibility of establishing the visualization models of intraneural microvessels of sciatic nerves in Sprague Dawley (SD) rats by systemic infusion of Evan's blue (EB) or lead oxide and to compare the advantages and disadvantages.

METHODS

Fifteen healthy adult SD rats of either gender, weighing 200-250 g, were randomly divided into traditional group (group A, n=5), fluorescence group (group B, n=5), and radiography group (group C, n=5). Ink, EB, and lead oxide, all mixed with gelatin solution, were injected in groups A, B, and C, respectively. After 2 hours of cryopreservation under 4 degrees C, all sciatic nerves were harvested and observed through stereomicroscope to make sure the filling condition. The two-dimentional (2D) images were then collected via reflexion fluorescent microscope in group B and via micro-CT scan in group C. All images were imported into computer to establish three-dimentional (3D) reconstruction models by Mimics 15.0.

RESULTS

All groups could show the outline of intraneural microvessels of sciatic nerves under stereomicroscope. Diameters of them were measured under fluorescent microscope, ranging from 10 microm to 30 microm. Both groups B and C could establish 3D reconstruction models from 2D images. These models could clearly reproduce the structure of microvessels.

CONCLUSION

Both EB and lead oxide can be used to establish 3D reconstruction models to observe structure of the intraneural vessels. However, EB has some disadvantages, such as predisposition to infiltration, grainy 2D images and time-consuming procedure; it is not suitable for researches of large specimen. Though 2D pictures from lead oxide have lower resolution than EB, it is easier to be manipulated and appropriate for experiments of large specimen.

Resveratrol attenuates hydrogen peroxide-induced apoptosis in human umbilical vein endothelial cells

BACKGROUND AND OBJECTIVES

  Vascular endothelium injury caused by reactive oxygen species (ROS) plays an initial role in the pathogenesis of atherosclerosis. Resveratrol, a natural polyphenolic compound, is well known to possess a variety of cardioprotective activities. In this study we first investigated the effects of resveratrol against apoptosis of human umbilical vein endothelial cells (HUVECs) induced by hydrogen peroxide (H2O2) in vitro and the possible mechanisms.

MATERIALS AND METHODS

HUVECs were pre-incubated with resveratrol (0.5-10 microM) for 120 min, and then challenged with 100 microM H2O2 for 30 min. The cell viability was evaluated by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay. The superoxide dismutase (SOD) activities and the reduced glutathione (GSH) contents were measured spectrophotometrically by using commercially available kits. The apoptosis of HUVECs was detected by Hoechst 33258 and Annexin-V/PI staining by flow cytometry staining using Fluorescence microscope. We also measured the mitochondrial membrane potential with the fluorescent probe JC-1 through Fluorescence microscope.

RESULTS

The study showed that incubation with resveratrol caused significant increase of the viability of HUVECs and the SOD activities and GSH contents, and decrease of cell apoptosis induced by H2O2, which was accompanied with the restoration of the mitochondrial membrane potential.

CONCLUSIONS

Our data suggested that resveratrol protected HUVECs against apoptosis induced by H2O2 through enhancing the antioxidant defenses, and inhibiting the degression of the mitochondrial membrane potential.  

Epigenetic screen identifies genotype-specific promoter DNA methylation and oncogenic potential of CHRNB4

Genome-wide association studies have highlighted three major lung cancer susceptibility regions at 15q25.1, 5p15.33 and 6p21.33. To gain insight into the possible mechanistic relevance of the genes in these regions, we investigated the regulation of candidate susceptibility gene expression by epigenetic alterations in healthy and lung tumor tissues. For genes up- or downregulated in lung tumors the influence of genetic variants on DNA methylation was investigated and in vitro studies were performed.

We analyzed 394 CpG units within 19 CpG islands in the susceptibility regions in a screening set of 34 patients. Significant findings were validated in an independent patient set (n=50) with available DNA and RNA. The most consistent overall DNA methylation difference between tumor and adjacent normal tissue on 15q25 was tumor hypomethylation in the promoter region of CHRNB4 with a median difference of 8% (p<0.001) which resulted in overexpression of the transcript in tumors (p<0.001). Confirming previous studies we also found hypermethylation in CHRNA3 and TERT with significant expression changes. Decitabine treatment of H1299 cells resulted in reduced methylation levels in gene promoters, elevated transcript levels of CHRNB4 and CHRNA3 and a slight downregulation of TERT demonstrating epigenetic regulation of lung cancer cells. SNPs rs421629 on 5p15.33 and rs1948, rs660652, rs8040868 and rs2036527 on 15q25.1, previously identified as lung cancer risk or nicotine addiction modifiers were associated with tumor DNA methylation levels in the promoters of TERT and CHRNB4 (p<0.001) respectively in two independent sample sets (n=82; n=150). In addition, CHRNB4 knock down in two different cell lines (A549 and H1299) resulted in reduced proliferation (p_A549<0.05;p_H1299L<0.001) and propensity to form colonies in H1299 cells.

These results suggest epigenetic deregulation of nicotinic acetylcholinereceptor subunit (nAChR) genes which in the case of CHRNB4 is strongly associated with genetic lung cancer susceptibility variants and a functional impact on tumorigenic potential.

[Study on immune response after repair of nerve defect with acellular nerve xenograft laden with allogenic adipose-derived stem cells in rhesus monkey]

OBJECTIVE

To observe the systemic and local immune response after repair of nerve defect with acellular nerve xenograft laden with allogenic adipose-derived stem cells (ADSCs) in rhesus monkey so as to evaluate the safety of the proposed material for nerve reconstruction.

METHODS

Bilateral tibial nerves were taken from a healthy adult male landrace (weighing 48 kg) to prepare acellular nerve xenograft by chemical extraction. ADSCs were isolated from a healthy adult male rhesus monkey (weighing 4.5 kg), and were seeded into the acellular nerve grafts. The radial nerve defect models with 25 mm in length were established in 10 healthy adult female rhesus monkeys (weighing 3-5 kg), and they were divided into cell-laden group (n = 5) and non-cell-laden group (n = 5) randomly. Defect was repaired with acellular nerve xenograft laden with allogenic ADSCs in cell-laden group, with acellular nerve xenograft only in non-cell-laden group. The blood samples were taken from peripheral vein preoperatively and at 14, 60, and 90 days after operation for lymphocyte analysis; at 5 months after operation, the grafts were harvested to perform histological examination for local immune response and nerve regeneration. The nerve autograft in rhesus monkey was used as control.

RESULTS

In cell-laden group and non-cell-laden group, no significant difference was found in the count of lymphocytes and T lymphocytes, the percentage ofT lymphocytes, CD8+ T lymphocytes, as well as the ratio of CD4+ T lymphocytes to CD8+ T lymphocytes between pre- and post-operation (P > 0.05); in cell-laden group, the percentage of CD4+ T lymphocytes at 14 days was significantly lower than that at 60 and 90 days postoperatively (P < 0.05). The percentage of CD4+ T lymphocytes in cell-laden group was significantly lower than that in non-cell-laden group at 14 days (P < 0.05), but no significant difference was found in the other indexes at the other time between 2 groups (P > 0.05). At 5 months after operation, mild adhesion was found on the surface of nerve xenografts; the epineurium of nerve xenografts was thicker than that of nerve autografts; and neither necrosis nor fibrosis was found. CD3+, CD4+, CD8+, CD68+, and CD163+ T lymphocytes were scattered within the grafts, in which regenerative axons were revealed. CD3+, CD4+, CD8+, CD68+, and CD163+ T lymphocytes were comparable in cell-laden group, non-cell-laden group, and autograft group.

CONCLUSION

Repair of nerve defect with acellular nerve xenograft elicits neither systemic nor local immune response in rhesus monkeys. Implantation of allogenic ADSCs might result in transient depression of CD4+ T lymphocytes proliferation early after surgery, no immune response can be found.

Cordycepin as a sensitizer to tumour necrosis factor (TNF)-α-induced apoptosis through eukaryotic translation initiation factor 2α (eIF2α)- and mammalian target of rapamycin complex 1 (mTORC1)-mediated inhibition of nuclear factor (NF)-κB

Cordycepin (3'-deoxyadenosine) is one of the major bioactive substances produced by Cordyceps militaris, a traditional medicinal mushroom. Cordycepin possesses several biological activities, including both pro-apoptotic and anti-apoptotic properties. In the present report, we investigated an effect of cordycepin on the survival of cells exposed to tumour necrosis factor (TNF)-α. We found that subtoxic doses of cordycepin increased susceptibility of cells to TNF-α-induced apoptosis. It was associated with suppression of nuclear factor-κB (NF-κB), a major prosurvival component involved in TNF-α signalling. The adenosine transporter and A₃ adenosine receptor, but not A₁ and A₂ adenosine receptors, mediated both anti-NF-κB and pro-apoptotic effects. We found that cordycepin had the potential to phosphorylate eukaryotic translation initiation factor 2α (eIF2α) and that activation of eIF2α mimicked the suppressive effect of cordycepin on the NF-κB pathway. Furthermore, activation of eIF2α sensitized cells to TNF-α-induced apoptosis. To identify molecular events downstream of eIF2α, the role of mammalian target of rapamycin complex 1 (mTORC1) was examined. Selective activation of ₃eIF2α, as well as treatment with cordycepin, caused phosphorylation of mTORC1. Rapamycin, an inhibitor of mTORC1, significantly reversed the suppressive effects of eIF2α on NF-κB. These results suggest that cordycepin sensitizes cells to TNF-α-induced apoptosis, at least in part, via induction of the eIF2α-mTORC1 pathway and consequent suppression of NF-κB.

Timing and magnitude of C partitioning through a young loblolly pine (Pinus taeda L.) stand using 13C labeling and shade treatments

The dynamics of rapid changes in carbon (C) partitioning within forest ecosystems are not well understood, which limits improvement of mechanistic models of C cycling. Our objective was to inform model processes by describing relationships between C partitioning and accessible environmental or physiological measurements, with a special emphasis on short-term C flux through a forest ecosystem. We exposed eight 7-year-old loblolly pine (Pinus taeda L.) trees to air enriched with (13)CO(2) and then implemented adjacent light shade (LS) and heavy shade (HS) treatments in order to manipulate C uptake and flux. The impacts of shading on photosynthesis, plant water potential, sap flow, basal area growth, root growth and soil CO(2) efflux rate (CER) were assessed for each tree over a 3-week period. The progression of the (13)C label was concurrently tracked from the atmosphere through foliage, phloem, roots and surface soil CO(2) efflux. The HS treatment significantly reduced C uptake, sap flow, stem growth and fine root standing crop, and resulted in greater residual soil water content to 1 m depth. Soil CER was strongly correlated with sap flow on the previous day, but not the current day, with no apparent treatment effect on the relationship. Although there were apparent reductions in new C flux belowground, the HS treatment did not noticeably reduce the magnitude of belowground autotrophic and heterotrophic respiration based on surface soil CER, which was overwhelmingly driven by soil temperature and moisture. The (13)C label was immediately detected in foliage on label day (half-life = 0.5 day), progressed through phloem by Day 2 (half-life = 4.7 days), roots by Days 2-4, and subsequently was evident as respiratory release from soil which peaked between Days 3 and 6. The δ(13)C of soil CO(2) efflux was strongly correlated with phloem δ(13)C on the previous day, or 2 days earlier. While the (13)C label was readily tracked through the ecosystem, the fate of root C through respiratory, mycorrhizal or exudative release pathways was not assessed. These data detail the timing and relative magnitude of C flux through various components of a young pine stand in relation to environmental conditions.

MDM2 regulates MYCN mRNA stabilization and translation in human neuroblastoma cells

The MYCN gene has a critical role in determining the clinical behavior of neuroblastoma. Although it is known that genomic amplification occurs in high-risk subsets, it remains unclear how MYCN expression is regulated in the pathogenesis of neuroblastomas. Here, we report that MYCN expression was regulated by the oncoprotein MDM2 at the post-transcriptional level and was associated with neuroblastoma cell growth. Increasing MDM2 by ectopic overexpression in the cytoplasm enhanced both mRNA and protein expression of MYCN. Mechanistic studies found that the C-terminal RING domain of the MDM2 protein bound to the MYCN mRNA's AREs within the 3'UTR and increased MYCN 3'UTR-mediated mRNA stability and translation. Conversely, MDM2 silencing by specific siRNA rendered the MYCN mRNA unstable and reduced the abundance of the MYCN protein in MYCN-amplified neuroblastoma cell lines. Importantly, this MDM2 silencing resulted in a remarkable inhibition of neuroblastoma cell growth and induction of cell death through a p53-independent pathway. Our results indicate that MDM2 has a p53-independent role in the regulation of both MYCN mRNA stabilization and its translation, suggesting that MDM2-mediated MYCN expression is one mechanism associated with growth of MYCN-associated neuroblastoma and disease progression.

[Temporary intravascular shunts for quick restoration of perfusion to the extremity with major vascular injury]

OBJECTIVE

To report clinical experience in the use of temporary intravascular shunts (TIVS) for quick restoration of perfusion to the extremity with major vascular injury.

METHODS

Between August 2009 and March 2011, TIVS was applied temporarily to restore blood perfusion to the extremity in 6 patients with major extremity vascular structure injury secondary to trauma (4 patients) or tumor resection (2 patients), who would received vascular transplantation and underwent long ischemia. The patterns of vascular shunts included external carotid artery-subclavian artery, axillary artery-axillary artery, axillary vein-subclavian vein, brachial artery-brachial artery, brachial vein-brachial vein, brachial artery-radial artery, femoral artery-popliteal artery, and popliteal artery-posterior tibial artery. After TIVS, extensive debridement, fracture fixation, or tumor excision was performed. Then the shunted tubes were removed, and the vessels were repaired definitely. Six vessels were repaired by transplanting the great saphenous veins; one vessel was anastomosed directly without tension; and one vessel was repaired by artificial vascular graft.

RESULTS

All shunted tubes were successfully established within 5 to 10 minutes (mean, 8.2 minutes). The duration of bypass ranged from 67 to 210 minutes. After establishment of TIVS, blood perfusion to the affected limb was improved. When shunted tubes were removed, thrombosis and partial obstruction occurred in one who accepted amputation, and the others kept patency. No loosening of tubes and haemorrhage occurred. At 2-15 months of follow-up, affected limbs had good blood supply.

CONCLUSION

TIVS is rapid and simple, which can quickly restore blood perfusion to the extremity with major vascular injury and shorten the ischemic time of the affected extremity.

Chmp1A acts as a tumor suppressor gene that inhibits proliferation of renal cell carcinoma

Renal cell carcinoma (RCC) is a highly malignant and often fatal disease of the kidney. Chmp1A is a member of the Endosomal Sorting Complex Required for Transport (ESCRT-III) family, and plays a role in the cytoplasm in sorting proteins to the multivesicular body (MVB). Chmp1A functions as a tumor suppressor gene and has been reported in pancreatic tumor cells. Here, we examined the expression level of Chmp1A in human RCC tissues and renal tumor cells by real-time quantitative RT-PCR and western blot. We found that the expression level of Chmp1A is significantly lower in RCC tissues and renal tumor cells compared with adjacent non-tumorous tissues and normal renal cells. Additionally, inhibition of Chmp1A expression by shRNA induced tumor formation in normal renal cells. However, inhibition of Chmp1A did not significantly affect tumor cell proliferation in vitro and tumor progression in vivo. Interestingly, overexpression of Chmp1A using a eukaryotic plasmid inhibited the proliferation of renal tumor cells in vitro and the growth of renal tumor in vivo. Thus, our results demonstrate that Chmp1A functions as a tumor suppressor gene in renal cells and may be a useful target for treatment of RCC.

Tensile plasticity in metallic glasses with pronounced β relaxations

Metallic glasses are commonly brittle, as they generally fail catastrophically under uniaxial tension. Here we show pronounced macroscopic tensile plasticity achieved in a La-based metallic glass which possesses strong β relaxations and nanoscale heterogeneous structures. We demonstrate that the β relaxation is closely correlated with the activation of the structural units of plastic deformations and global plasticity, and the transition from brittle to ductile in tension and the activation of the β relaxations follow a similar time-temperature scaling relationship. The results have implications for understanding the mechanisms of plastic deformation and structural origin of β relaxations as well as for solving the brittleness in metallic glasses.

[Elementary research of constructive feature and three-dimensional reconstruction of nerve bundles of C7 anterior and posterior division end]

OBJECTIVE

To observe the distribution feature of nerve bundles in C7 nerve anterior and posterior division end.

METHODS

The brachial plexus specimen was harvested from 1 fresh adult cadaver. After C7 nerve was confirmed, the distal end of anterior and posterior division was dissected and embedded by OCT. Then the samples were serially horizontally sliced with each 10 microm deep. After acetylcholinesterase (AChE) histochemical staining, the stain characteristics of different nerve fiber bundles were observed and amount of the nerve fiber bundles were counted under optic-microscope. At last, the imaging which were collected were three-dimensional (3-D) reconstructed by using Amira 4.1 software.

RESULTS

There was no obvious difference in the stain between the anterior and posterior divisions. The running of the nerve fiber bundles were dispersive from proximal end of nerve to distal end of nerve. Nerve fiber bundles of anterior division were mainly sensor nerve fiber bundles, which located in medial side. Nerve fiber bundles of posterior division were mainly moter nerve fiber bundles, having no regularity in the distribution of nerve fiber bundles. The total number of nerve fiber bundles in distal end of anterior division was 7.85 +/- 1.04, the number of motor nerve fiber bundles was 2.85 +/- 0.36, and the number of sensor nerve fiber bundles was 5.13 +/- 1.01. The total number of nerve fiber bundles in distal end of posterior division was 9.79 +/- 1.53, the number of motor nerve fiber bundles was 6.00 +/- 0.69, and the number of sensor nerve fiber bundles was 3.78 +/- 0.94. There were significant differences in the numbers of motor and sensor nerve fiber bundles between anterior and posterior divisions (P < 0.05). The microstructure 3-D model was reconstructed based on serial slice through Amira 4.1. The intercross and recombination process of nerves bundles could be observed obviously. The nerve bundle distribution showed cross and combination.

CONCLUSION

Nerve fiber bundles of anterior division are mainly sensor nerve fiber bundles and locate in medial side. Nerve fiber bundles of posterior division are mainly motor nerve fiber bundles, which has no regularity in the distribution of nerve fiber bundles. The 3-D reconstruction can display the internal structure feature of the C7 division end.

A phase I/II prospective, single arm trial of gefitinib, trastuzumab, and docetaxel in patients with stage IV HER-2 positive metastatic breast cancer

Inhibition of the HER-2 pathway via the monoclonal antibody trastuzumab has had a major impact in treatment of HER-2 positive breast cancer, but de novo or acquired resistance may reduce its effectiveness. The known interplay between the epidermal growth factor receptor (EGFR) and HER-2 receptors and pathways creates a rationale for combined anti-EGFR and anti-HER-2 therapy in HER-2 positive metastatic breast cancer (MBC), and toxicities associated with the use of multiple chemotherapeutic agents together with biological therapies may also be reduced. We conducted a prospective, single arm, phase I/II trial to determine the efficacy and toxicity of the combination of trastuzumab with the EGFR inhibitor gefitinib and docetaxel, in patients with HER-2 positive MBC. The maximum tolerated dose (MTD) was determined in the phase I portion. The primary end point of the phase II portion was progression-free survival (PFS). Immunohistochemical analysis of biomarker expression of the PKA-related proteins cAMP response element-binding protein (CREB), phospho-CREB and DARPP-32 (dopamine and cAMP-regulated phosphoprotein of 32 kDa) plus t-DARPP (the truncated isoform of DARPP-32); PTEN; p-p70 S6K; and EGFR was conducted on tissue from metastatic sites. Nine patients were treated in the phase I portion of the study and 22 in the phase II portion. The MTD was gefitinib 250 mg on days 2-14, trastuzumab 6 mg/kg, and docetaxel 60 mg/m(2) every 21 days. For the 29 patients treated at the MTD, median PFS was 12.7 months, with complete and partial response rates of 18 and 46%, and a stable disease rate of 29%. No statistically significant correlation was found between response and expression of any biomarkers. We conclude that the combination of gefitinib, trastuzumab, and docetaxel is feasible and effective. Expression of the biomarkers examined did not predict outcome in this sample of HER-2 overexpressing metastatic breast cancer.