Methamphetamine Dysregulates Redox Status in Primary Rat Astrocyte and Mesencephalic Neuronal Cultures

Astrocytes provide structural, metabolic and trophic support to neurons. They are directly involved in the regulation of neuronal transmission and synaptic activity and respond to the synaptic release and remove neurotransmitters from the extracellular fluid. The dysfunction of astrocytes has been implicated in multiple neurotoxicities, including those associated with drugs of abuse. Methamphetamine (METH) has long-lasting neurotoxic effects, yet little is known about the mechanisms that govern METH-induced neural dysfunction, and especially the astrocytic control over the extracellular milieu. The purpose of this study was to clarify the response of astrocytes and neurons treated with METH and determine their relative sensitivity to this drug of abuse. Confluent rat primary astrocyte and mesencephalic neuron cultures were treated for 24 hrs with 0, 0.1, 0.5 or 1 mM METH, and the initial rate of glutamate and glutamine uptake was measured over a 5 min period. Additional studies examined the effect of METH (24 hr exposure at similar concentrations) on oxidative endpoints, namely glutathione (GSH) levels, lactate dehydrogenase (LDH) release and isoprostane (IsoP) levels, considered to be the most accurate biomarker of lipid peroxidation. There was no effect of METH on the rates of glutamate and glutamine uptake, and these were indistinguishable from controls. However, METH concentration-dependently affected astrocytic and neuronal GSH levels, leading to a significant decrease in redox potential at all of the tested concentrations (p<0.05). METH also significantly enhanced astrocytic LDH release at the 0.5 and 1.0 mM exposures. Consistent with the changes in IsoPs, METH (0.5 and 1.0 mM) also increased the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor with a key role in regulating oxidative stress responses. However, this Nrf2 increased in expression was observed only in astrocytes and no effect was noted in neurons. Taken together, this study establishes that METH affects both astrocyte and neuronal functions, and that oxidative stress is a proximate mechanism for METH's-induced neurotoxicity on both cell types. Furthermore, in response to oxidative stress astrocytes efficiently upregulated Nrf2 nuclear translocation and transcription. These effects were absent in neurons. Combined with their lower content of GSH, these characteristics may account for the greater sensitivity of neurons to METH-induce toxicity.

Phase III, randomized, open-label, first-line study of gefitinib (G) versus carboplatin/paclitaxel (C/P) in selected patients (pts) with advanced non-small cell lung cancer (NSCLC) (IPASS): Evaluation of recruits in Japan

8044^

Background: The IRESSA Pan Asia Study (IPASS) demonstrated superiority of G vs C/P in 1,217 clinically selected chemonaïve pts in Asia with advanced NSCLC. PFS favored C/P initially then G, likely driven by different outcomes according to EGFR mutation (M) status. We report the planned analyses of 233 recruits in Japan (19% of overall population). Methods: From Mar 06 to Oct 07, chemonaïve, never/light ex-smokers with stage IIIB/IV NSCLC and adenocarcinoma histology were randomized to G 250 mg/day (n=114) or C (AUC 5 or 6)/P (200 mg/m2) (n=119). Primary objective was PFS in ITT population; a treatment by country interaction test (Japan vs other) was performed. Secondary endpoints were overall survival (OS), objective response rate (ORR, RECIST), QoL (FACT-L, TOI), symptom improvement (LCS subscale of FACT-L), and tolerability. Results: PFS results in pts in Japan did not significantly differ from other pts (interaction test p=0.4736). G demonstrated superior PFS compared with C/P (HR 0.69; 95% CI 0.51–0.94; p=0.0191); effect was not constant over time, favoring C/P initially then G. Preliminary OS (25% maturity; follow-up ongoing) was similar for G and C/P (HR 0.89; 95% CI 0.53–1.48). ORR for G was 41% vs 35% for C/P;odds ratio [OR] 1.34; 95% CI 0.78–2.30; p=0.2967. QoL improvement rate (TOI) was 43% for G and 28% for C/P (OR 1.92; 95% CI 1.11–3.34; p=0.0200); QoL (FACT-L 41 vs 43%; OR 0.94; 95% CI 0.56–1.60; p=0.8263) and symptom (LCS 42 vs 46%; OR 0.85; 95% CI 0.50–1.43; p=0.5340) improvement rates were similar for G and C/P. Tolerability profile was more favorable with G than C/P. There were no deaths due to ILD-type events (frequency 1.8% [G] vs 0% [C/P]). Conclusions: Efficacy and safety data for pts in Japan were generally consistent with overall population. G demonstrated improved PFS and ORR, similar OS, higher QoL (TOI) and similar symptom improvement rates, and a more favorable tolerability profile compared with C/P in chemonaïve, never/light ex-smokers with advanced NSCLC and adenocarcinoma histology. In IPASS, EGFR M status appeared to be a strong predictive biomarker for G efficacy compared with C/P.

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ASCO Conflict of Interest Policy and Exceptions

In compliance with the guidelines established by the ASCO Conflict of Interest Policy (J Clin Oncol. 2006 Jan 20;24[3]:519–521) and the Accreditation Council for Continuing Medical Education (ACCME), ASCO strives to promote balance, independence, objectivity, and scientific rigor through disclosure of financial and other interests, and identification and management of potential conflicts. According to the ASCO Conflict of Interest Policy, the following financial and other relationships must be disclosed: employment or leadership position, consultant or advisory role, stock ownership, honoraria, research funding, expert testimony, and other remuneration (J Clin Oncol. 2006 Jan 20;24[3]:520). The ASCO Conflict of Interest Policy disclosure requirements apply to all authors who submit abstracts to the Annual Meeting.

For clinical trials that began accrual on or after April 29, 2004, ASCO's Policy places some restrictions on the financial relationships of principal investigators (J Clin Oncol. 2006 Jan 20;24[3]:521). If a principal investigator holds any restricted relationships, his or her abstract will be ineligible for placement in the 2009 Annual Meeting unless the ASCO Ethics Committee grants an exception. Among the circumstances that might justify an exception are that the principal investigator (1) is a widely acknowledged expert in a particular therapeutic area; (2) is the inventor of a unique technology or treatment being evaluated in the clinical trial; or (3) is involved in international clinical oncology research and has acted consistently with recognized international standards of ethics in the conduct of clinical research. NIH-sponsored trials are exempt from the Policy restrictions. Abstracts for which authors requested and have been granted an exception in accordance with ASCO's Policy are designated with a caret symbol (^) in the Annual Meeting Proceedings.

For more information about the ASCO Conflict of Interest Policy and the exceptions process, please visit www.asco.org/conflictofinterest .

Differential expression of apoptosis-related genes in the cochlea of noise-exposed rats

Exposure to intense noise induces apoptosis in hair cells in the cochlea. To identify the molecular changes associated with noise-induced apoptosis, we used quantitative real-time PCR to evaluate the changes in 84 apoptosis-related genes in cochlear samples from the sensory epithelium and lateral wall. Sprague-Dawley rats exposed to a continuous noise at 115 dB SPL for 2 h. The exposure caused a 40-60 dB threshold shift 4 h post-exposure that decreased to 20-30 dB 7 days post-exposure. These functional changes were associated with apoptotic markers including nuclear condensation and fragmentation and terminal deoxynucleotidyl transferase dUTP nick end labeling staining. Immediately after the noise exposure, 12 genes were downregulated, whereas only one gene (Traf4) was upregulated. At 4 h post-exposure, eight genes were upregulated; three (Tnrsf1a, Tnfrsf1b, Tnfrst5) belonged to the Tnfrsf family, three (Bir3, Mcl1 and Prok2) have anti-apoptotic properties and one (Gadd45a) is a target of p53. At 7 days post-exposure, all the upregulated genes returned to pre-noise levels. Interestingly, the normal control cochlea had high constitutive levels of several apoptosis-related genes. These constitutively expressed genes, together with the inducible genes, may participate in the induction of cochlear apoptotic activity.

Epidemiology and clinical management of cardiomyopathies and heart failure in China

Heart failure (HF), a syndrome of clinical symptoms and signs, is the most serious and the final outcome of all heart diseases and as in other parts of the world it is a common cause for admission to hospital in the Chinese population. In this review the epidemiological data on cardiomyopathies, HF and current treatment for chronic HF among people living in China are summarised.

In vitro culture and differentiation of buffalo (Bubalus bubalis) spermatogonia

The objective of this study was to develop a culture system which could support buffalo spermatogonia differentiation into spermatids in vitro. Testes from 3- to 5-month-old buffaloes were decapsulated and seminiferous tubules were enzymatically dissociated to recover spermatogonia and sertoli cells. The cells were cultured in modified Dulbecco modified Eagle medium supplemented with different concentrations of foetal bovine serum, retinol, testosterone for 2 months at 37 degrees C. Spermatogonia and sertoli cells were identified with an antibody against c-kit or GATA4, respectively. The viability of spermatogonia in the media supplemented with different concentrations of serum was all significantly higher (p < 0.05) compared with that in the medium without serum. A-paired or A-aligned spermatogonia and spermatogonial colonies (AP-positive) were observed after 7-10 days of culture and spermatid-like cells with a flagellum (6-8 microm) appeared after 30 days of culture. For cultured conditions, retinol could not significantly promote the formation of spermatid-like cells (p > 0.05), whereas supplementation of testosterone could significantly promote (p < 0.05) the formation of spermatid-like cells after 41 days of culture. The expression of the spermatid-specific marker gene (PRM2) was identified after 30 days of culture by RT-PCR. Yet, the transition protein 1 (TP1, a haploid makers) was not detected. Meanwhile, spermatids developed in vitro were also confirmed by Raman spectroscopy. These results suggest that buffalo spermatogonia could differentiate into spermatids in vitro based on the analysis of their morphology, PRM2 expression and Raman spectroscopy. Yet, the normality of the spermatid-like cells was not supported by TP1 expression.

Downregulation of Wnt2 and beta-catenin by siRNA suppresses malignant glioma cell growth

Increasing evidence suggests that aberrant activation of Wnt signaling is involved in tumor development and progression. Our earlier study on gene expression profile in human gliomas by microarray found that some members of Wnt family were overexpressed. To further investigate the involvement of Wnt signaling in gliomas, the expression of core components of Wnt signaling cascade in 45 astrocytic glioma specimens with different tumor grades was examined by reverse transcription-PCR and immunohistochemistry. Wnt2, Wnt5a, frizzled2 and beta-catenin were overexpressed in gliomas. Knockdown of Wnt2 and its key mediator beta-catenin in the canonical Wnt pathway by siRNA in human U251 glioma cells inhibited cell proliferation and invasive ability, and induced apoptotic cell death. Furthermore, treating the nude mice carrying established subcutaneous U251 gliomas with siRNA targeting Wnt2 and beta-catenin intratumorally also delayed the tumor growth. In both in vitro and in vivo studies, downregulation of Wnt2 and beta-catenin was associated with the decrease of PI3K/p-AKT expression, indicating the interplay between Wnt/beta-catenin and PI3K/AKT signaling cascades. In conclusion, the canonical Wnt pathway is of critical importance in the gliomagenesis and intervention of this pathway may provide a new therapeutic approach for malignant gliomas.

Oncolytic adenovirus retargeted to Delta-EGFR induces selective antiglioma activity

The fact that glioblastomas, which are one of the most devastating cancers, frequently express the Delta-EGFR (epithelial growth factor receptor) also called mutant variant III of EGFR (EGFRvIII) suggests that this cancer cell-specific receptor might serve as an ideal target for cancer therapy. To assess its potential as such a target, we constructed an oncolytic adenovirus with Retargeted Infectivity Via EGFR (Delta-24-RIVER) on the backbone of Delta-24. This new oncolytic adenovirus targets, as Delta-24 does, the disrupted Rb pathway in cancer cells; in addition, this adenovirus has also been retargeted through the abrogation of CAR binding (Y477A mutation in adenoviral fiber protein) and insertion of an EGFRvIII-specific binding peptide in the HI loop of the fiber protein. As compared with Delta-24, Delta-24-RIVER induced EGFRvIII-selective cytotoxicity in U-87 MG isogenic cell lines and in tetracycline-inducible EGFRVIII expressing U-251 MG cells. Accordingly, by tittering the viral progeny and examining fiber protein expression in the above cells, we showed that the replication of this new construct also correlated with EGFRvIII expression. Consistently, immunohistochemistry staining of the adenoviral capsid protein hexon in the virus-treated tumors revealed that the virus replicated more efficiently in EGFRvIII-expressing U-87 MG.DeltaEGFR xenografts than in the tumors grown from U-87 MG cells. Importantly, treatment with Delta-24-RIVER prolonged the survival of animals with intracranial xenografts derived from U-87 MG.DeltaEGFR cells. Therefore, our results constitute the first proof of the direct targeting of a cancer-specific receptor using an oncolytic adenovirus.

Mechanical properties of functionalized carbon nanotubes

Carbon nanotubes (CNTs) used to reinforce polymer matrix composites are functionalized to form covalent bonds with the polymer in order to enhance the CNT/polymer interfaces. These bonds destroy the perfect atomic structures of a CNT and degrade its mechanical properties. We use atomistic simulations to study the effect of hydrogenization on the mechanical properties of single-wall carbon nanotubes. The elastic modulus of CNTs gradually decreases with the increasing functionalization (percentage of C-H bonds). However, both the strength and ductility drop sharply at a small percentage of functionalization, reflecting their sensitivity to C-H bonds. The cluster C-H bonds forming two rings leads to a significant reduction in the strength and ductility. The effect of carbonization has essentially the same effect as hydrogenization.

Differential regulation of collagen types I and III expression in cardiac fibroblasts by AGEs through TRB3/MAPK signaling pathway

Advanced glycation end products (AGEs) play an important role in collagen deposition in diabetic cardiomyopathy. TRB3, a mammalian homolog of Drosophila tribbles, functions to increase glucose intolerance and regulates cell proliferation. We demonstrated that AGEs induce collagen type I expression but inhibit collagen type III expression, accompanied by increased TRB3 expression. Furthermore, the collagen type I induced byAGEs was down-regulated after inhibition of ERK and p38-MAPK, the collagen type III reduced by AGEs was up-regulated after inhibition of ERK. The expression of collagen types I and III regulated by AGEs through MAPK was partly reversed after treatment with TRB3 siRNA. It suggests that the TRB3/MAPK signaling pathway participates in the regulation of collagen types I and III by AGEs and may provide new therapeutic strategies for diabetic cardiomyopathy.

Stiffness and thickness of boron-nitride nanotubes

We establish an analytic approach to determine the tensile and bending stiffness of a hexagonal boron-nitride (h-BN) monolayer and single- and multi-wall boron-nitride nanotubes (BNNTs) directly from the interatomic potential. Such an approach enables one to bypass atomistic simulations and to give the tensile and bending stiffness in terms of the parameters in the potential. For single- and multi-wall BNNTs, the stiffness also depends on the (inner most or outer most) wall radius and the number of the walls. The thickness of h-BN monolayer is also discussed.

Constitutively active Rheb induces oncogenic transformation

Rheb (Ras-homolog enriched in brain) is a component of the phosphatidylinositol 3-kinase (PI3K) target of rapamycin (TOR) signaling pathway, functioning as a positive regulator of TOR. Constitutively active mutants of Rheb induce oncogenic transformation in cell culture. The transformed cells are larger and contain more protein than their normal counterparts. They show constitutive phosphorylation of the ribosomal protein S6 kinase and the eukaryotic initiation factor 4E-binding protein 1, two downstream targets of TOR. The TOR-specific inhibitor rapamycin strongly interferes with transformation induced by constitutively active Rheb, suggesting that TOR activity is essential for the oncogenic effects of mutant Rheb. Rheb-induced transformation is also dependent on a C-terminal farnesylation signal that mediates localization to a cellular membrane. An engineered N-terminal myristylation signal can substitute for the farnesylation. Immunofluorescence localizes wild-type and mutant Rheb to vesicular structures in the cytoplasm, overlapping with the endoplasmic reticulum.