Heterogeneities in CuZr-based bulk metallic glasses studied by x-ray scattering

Inhomogeneities in two CuZr-based bulk metallic glasses (BMGs) were studied by using synchrotron radiation x-ray scattering techniques. (Cu(4.5/5.5)Ag(1/5.5))(46)Zr(46)Al(8) BMG was found to be more inhomogeneous than Cu(46)Zr(46)Al(8) BMG on the small length scale, where Cu and Ag atoms form enriched zones. Such heterogeneities are locally favorable for forming close-packed icosahedron-like clusters in three-dimensional space, greatly promoting the glass forming ability of this alloy. Upon annealing near the T(g) temperature, the heterogeneities were reduced initially at low temperature and short time annealing, then regenerated again for temperature increase and time extension. The average environment around Zr atoms almost does not change. However, the heterogeneity increases for Cu, Zr and Ag atoms once nanocrystallization happens.

M. Abstract PD07-03: A Genomic Predictor of Survival Following Taxane-Anthracycline Chemotherapy for Breast Cancer

Background: There is currently no predictive assay for patients with clinical Stage II-III breast cancer from which predicted sensitivity to treatment is associated with high probability of survival following chemotherapy.

Patients & Methods: We performed Affymetrix gene expression microarrays of prospectively collected tumor biopsies from 508 patients with newly diagnosed HER2-normal invasive breast cancer prior to neoadjuvant taxane-anthracycline chemotherapy followed by adjuvant endocrine therapy (if hormone receptor-positive). The predictor was developed from 310 samples (from MDACC & I-SPY) by combining: 1) a signature to predict sensitivity to endocrine therapy (SET); 2) estrogen receptor (ER)-stratified predictive signatures of resistance to chemotherapy, defined as extensive residual cancer burden (RCB-III) or relapse within 3 years; and 3) ER-stratified predictive signatures of response to chemotherapy, defined as pathologic complete response (pCR) or minimal RCB (RCB-I). The predictor classified tumors as treatment sensitive if high or intermediate SET, or if predicted to be responsive (and not resistant) to chemotherapy. Otherwise, tumors were classified as treatment insensitive. The predictor was then tested on an independent cohort (N= 198, 98% with clinical Stage II-III) who received neoadjuvant (N= 180) or adjuvant (N= 18) taxane-anthracycline chemotherapy (from MDACC, USO, GEICAM, Peru, LBJ). Distant relapse-free survival (DRFS) was evaluated at a 3-year median follow up using negative predictive value (NPV, absence of event if predicted to be sensitive), and absolute risk reduction (ARR) for those predicted to be sensitive (versus insensitive), with 95% confidence interval (CI). The independent predictive value was assessed in multivariate Cox regression analysis based on the likelihood ratio test (P≥0.05). Results: Patients in the independent validation cohort who were predicted to be treatment sensitive (28%) had excellent DRFS, with NPV 92% (CI 85-100) and significant absolute risk reduction (ARR 18%, CI 6-28) at 3 years, compared to those predicted to be insensitive. This was similar to the DRFS observed in patients who achieved pCR after they completed neoadjuvant chemotherapy (NPV 93%, CI 85-100). Predictions were accurate in each phenotypic subset: ER+/HER2- (30% predicted sensitive, NPV 97%, CI 91-100; ARR 11%, CI 0.1-21) and ER-/HER2- (26% predicted sensitive, NPV 83%, CI 68-100; ARR 26%, CI 4-28). Predicted treatment sensitivity (HR 0.20, CI 0.07-0.57), ER+ status (HR 0.32, CI 0.17-0.63), clinical tumor stage T3-4 (HR 2.04, CI 1.07-3.88) and age >50 (HR 0.50, CI 0.25-0.98) were significant in a multivariate model that also included clinical nodal status, grade, and type of taxane used.

Conclusion: We report validation results for the first molecular predictor of sensitivity to neoadjuvant/adjuvant systemic therapy for clinical Stage II-III breast cancer that is independently associated with excellent DRFS in those predicted to be sensitive. Predictions were accurate for both ER+/HER2- and ER-/HER2- invasive breast cancer.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr PD07-03.

Schwann-like cell differentiation of rat adipose-derived stem cells by indirect co-culture with Schwann cells in vitro

OBJECTIVES

Schwann cell (SC) transplantation is a promising therapy for peripheral nerve transaction, however, clinical use of SCs is limited due to their very limited availability. Adipose-derived stem cells (ADSCs) have been identified as an alternative source of adult stem cells in recent years. The aim of this study was to evaluate the feasibility of using ADSCs as a source of stem cells for differentiation into Schwann-like cells by an indirect co-culture approach, in vitro.

MATERIALS AND METHODS

Multilineage differentiation potential of the obtained ADSCs was assayed by testing their ability to differentiate into osteoblasts and adipocytes. The ADSCs were co-cultured with SCs to be induced into Schwann-like cells through proximity, using a Millicell system. Expression of typical SC markers S-100, GFAP and P75NTR of the treated ADSCs was determined by immunocytochemical staining, western blotting and RT-PCR. Myelination capacity of the differentiated ADSCs (dADSCs) was evaluated in dADSC/dorsal root ganglia neuron (DRGN) co-cultures.

RESULTS

The treated ADSCs adopted a spindle shaped-like morphology after co-cultured with SCs for 6 days. All results of immunocytochemical staining, western blotting and RT-PCR showed that the treated cells expressed S-100, GFAP and P75NTR, indications of differentiation. dADSCs could form Schwann-like cell myelin in co-culture with DRGNs. Undifferentiated ADSCs (uADSCs) did not form myelin compared to DRGNs cultured alone, but could produce neurite extension.

CONCLUSIONS

These results demonstrate that this indirect co-culture microenvironment could induce ADSCs to differentiate into Schwann-like cells in vitro, which may be beneficial for treatment of peripheral nerve injuries in the near future.

An investigation of reversal of imatinib resistance in the Bcr-Abl positive imatinib-resistant cell line K562r by dasatinib, nilotinib, rapamycin and bortezomib

INTRODUCTION

We investigated the second-generation tyrosine kinase inhibitors, dasatinib and nilotinib, for their potential to overcome resistance in the imatinib-resistant K562 cell line, and evaluated whether rapamycin, an mammalian target of rapamycin (mTOR) inhibitor, and bortezomib, a proteasome inhibitor, could increase imatinib sensitivity in resistant cell lines.

METHODS

Cell lines, including K562 (chronic myeloid leukaemia in blast crisis) and K562r (imatinib-resistant K562), were exposed to dasatinib, nilotinib, rapamycin, bortezomib, and rapamycin plus imatinib. Cell proliferation was measured by 3-[4, 5-dimethylthia-zol-2-yl]-2, 5-diphenyl tetrazolium bromide (MTT) assay and mTOR signaling pathways were assessed by Western blotting.

RESULTS

Dasatinib, nilotinib, and bortezomib inhibited proliferation of K562 and K562r cell lines at nm concentrations. Resistance of K562r due to duplication of autophosphorylation of wild-type Bcr-Abl was not overcome by dasatinib and nilotinib, but was sensitive to bortezomib. Rapamycin partially inhibited proliferation of K562 and K562r cell lines. Rapamycin plus imatinib did not have a more inhibitory effect on the proliferation of K562 and K562r cell lines.

CONCLUSION

K562r due to duplication of autophosphorylation of wild-type Bcr-Abl induced by imatinib was still partially resistant to dasatinib and nilotinib, but this was overcome by incremental dosing. Rapamycin did not enhance imatinib sensitivity. The blockade of the ubiquitin-proteasome pathway could be effective in overcoming resistance in the K562r imatinib-resistant cell line.

Electronic excitations in B12As2 and their temperature dependence by vacuum ultraviolet ellipsometry

The dielectric response function of epitaxial B(12)As(2) films on 4H-SiC was determined at room temperature and at 10 K in the spectral region of 3.6-9.8 eV, i.e., in the vacuum ultraviolet (VUV) spectral region, by synchrotron ellipsometry. The experimental dielectric function was simulated with the critical point parabolic band model. The parameters of the dispersive structures were derived by numerical fitting of the experimental data to the proposed model. New high energy optical transitions are resolved at 5.95, 7.8 and 8.82 eV and their lineshape and origin are discussed. The temperature dependence of the critical point energies and transition strengths was determined, and the excitonic effect is considered.

Low-density to high-density transition in Ce75Al23Si2 metallic glass

Using in situ high-pressure x-ray diffraction (XRD), we observed a pressure-induced polyamorphic transition from the low-density amorphous (LDA) state to the high-density amorphous (HDA) state in Ce(75)Al(23)Si(2) metallic glass at about 2 GPa and 300 K. The thermal stabilities of both LDA and HDA metallic glasses were further investigated using in situ high-temperature and high-pressure XRD, which revealed different pressure dependences of the onset crystallization temperature (T(x)) between them with a turning point at about 2 GPa. Compared with Ce(75)Al(25) metallic glass, minor Si doping shifts the onset polyamorphic transition pressure from 1.5 to 2 GPa and obviously stabilizes both LDA and HDA metallic glasses with higher T(x) and changes their slopes dT(x)/dP. The results obtained in this work reveal another polyamorphous metallic glass system by minor alloying (e.g. Si), which could modify the transition pressure and also properties of LDA and HDA metallic glasses. The minor alloying effect reported here is valuable for the development of more polyamorphous metallic glasses, even multicomponent bulk metallic glasses with modified properties, which will trigger more investigations in this field and improve our understanding of polyamorphism and metallic glasses.

Two polymorphisms in the TIM-4 gene are associated with asthma in a Chinese Han population

The gene family of the T cell immunoglobulin and mucin domain (TIM) proteins encodes cell surface receptors that are involved in the regulation of Th1- and Th2-cell-mediated immunity. TIM-1 gene has been found to be associated with asthma in several populations. TIM-4, the natural ligand for TIM-1, may influence the susceptility to asthma.To investigate the association of the TIM-4 gene polymorphisms with asthma in a Chinese Han population. Three single nucleotide polymorphisms (SNPs) in TIM-4 gene, rs6882076, rs12658558 and rs4702747, were genotyped in 551 unrelated asthma patients and 549 healthy controls. We found that two SNPs of the TIM-4 gene, rs6882076 and rs4702747, were associated with asthma susceptibility in our study population (with P-values = 0.009 and 0.005 respectively). No association was observed between asthma and rs12658558. Our results suggest that TIM-4 gene polymorphisms are associated with asthma in a Chinese Han population.

Hypoxic neonatal pulmonary arterial myocytes are sensitized to ROS-generated 8-isoprostane

8-Isoprostane, a ROS-derived prostanoid that acts via the thromboxane receptor (TP), is implicated in neonatal pulmonary hypertension. The purpose of this study was to examine the effect of hypoxia on vascular smooth muscle ROS generation, 8-isoprostane activity, and TP binding. First-passage neonatal porcine pulmonary artery myocytes were exposed to 10% O(2) (hypoxic myocytes; HM) or 21% O(2) (normoxic myocytes) for 72 h. Hypoxia increased in vitro generation of ROS, superoxide, and 8-isoprostane. ROS generation was ablated by inhibition of mitochondrial complex III. SOD1 and 3 activities were increased, but SOD2 activity decreased by 45% in HM. 8-Isoprostane generation was driven by the addition of peroxide and nitric oxide; incubation with permeative PEG-SOD, but not PEG-catalase or impermeative SOD, attenuated hypoxia-induced 8-isoprostane generation. 8-Isoprostane affinity for TP was markedly increased in HM. Myocyte 8-isoprostane challenge caused TP internalization and calcium release only in HM; this was sensitive to TP blockade and was normalized by activation of adenylyl cyclase. We propose that hypoxia induces superoxide accumulation in pulmonary artery myocytes through inhibition of mitochondrial SOD2 activity, promoting peroxynitrite-induced generation of 8-isoprostane. 8-Isoprostane binds to sensitized TP receptors, causing receptor internalization and signaling to calcium release in hypoxic myocytes. 8-Isoprostane may be an important pulmonary vasoconstrictor during neonatal hypoxia.

Adipogenesis in ducks interfered by small interfering ribonucleic acids of peroxisome proliferator-activated receptor gamma gene

Peroxisome proliferator-activated receptor γ (PPARγ) participates in adipocyte differentiation and maintenance, including the promotion of lipid storage in mammals. In the present study, 3 duck PPARγ small interfering RNA (siRNA) expression plasmids were constructed to investigate the effect of downregulating the expression of PPARγ on adipogenesis and fat accumulation in ducks. The results indicate that the 3 siRNA specific for conserved regions of PPARγ can effectively inhibit expression of PPARγ. It was demonstrated that the expression of lipoprotein lipase and adipocyte fatty acid-binding protein in duck adipose tissue is repressed when the expression of PPARγ is downregulated by siRNA. At the same time, the weight of abdominal fat at 21 and 35 d of age is decreased significantly (P < 0.05) compared with the control. However, the triglyceride levels in serum and muscle are not affected when the mRNA of PPARγ is repressed. The current study indicates that the suppression of PPARγ reduces abdominal fat deposition and regulates adipogenesis in ducks.

Stem cell collection in unmanipulated HLA-haploidentical/mismatched related transplantation with combined granulocyte-colony stimulating factor-mobilised blood and bone marrow for patients with haematologic malignancies: the impact of donor characteristics and procedural settings

Unmanipulated haploidentical/mismatched related transplantation with combined granulocyte-colony stimulating factor-mobilised peripheral blood stem cells (G-PBSCs) and granulocyte-colony stimulating factor-mobilised bone marrow (G-BM) has been developed as an alternative transplantation strategy for patients with haematologic malignancies. However, little information is available about the factors predicting the outcome of peripheral blood stem cell (PBSC) collection and bone marrow (BM) harvest in this transplantation. The effects of donor characteristics and procedure factors on CD34⁺ cell yield were investigated. A total of 104 related healthy donors received granulocyte-colony stimulating factor (G-CSF) followed by PBSC collection and BM harvest. Male donors had significantly higher yields compared with female donors. In multiple regression analysis for peripheral blood collection, age and flow rate were negatively correlated with cell yield, whereas body mass index, pre-aphaeresis white blood cell (WBC) and circulating immature cell (CIC) counts were positively correlated with cell yields. For BM harvest, age was negatively correlated with cell yields, whereas pre-BM collection CIC counts were positively correlated with cell yield. All donors achieved the final product of ≥6 ×10⁶ kg⁻¹ recipient body weight. This transplantation strategy has been shown to be a feasible approach with acceptable outcomes in stem cell collection for patients who received HLA-haploidentical/mismatched transplantation with combined G-PBSCs and G-BM. In donors with multiple high-risk characteristics for poor aphaeresis CD34⁺ cell yield, BM was an alternative source.

Effects of spironolactone on atrial structural remodelling in a canine model of atrial fibrillation produced by prolonged atrial pacing

BACKGROUND AND PURPOSE

Suppression of the renin-angiotensin-aldosterone system can prevent atrial fibrillation (AF) by attenuating atrial structural remodelling but the role of aldosterone in AF prevention has not been investigated thoroughly. We explored whether the aldosterone antagonist, spironolactone, could improve atrial structural remodelling in long-term rapid pacing-induced AF.

EXPERIMENTAL APPROACH

Three groups of dogs were used, sham-operated, control and spironolactone-treated groups. Dogs in the control and spironolactone groups had right atrial pacing for 6 weeks. The spironolactone group was given spironolactone 1 week before and during the atrial pacing. After 6 weeks of pacing, atrial structural and functional changes were assessed by echocardiography, haemodynamic parameters by cardiac catheterization, histopathological changes by light and electron microscopy and cardiomyocyte apoptosis by TUNEL. Caspase-3, Bcl-2, bax, calpain I, calpastatin, matrix metalloproteinase (MMP)-9 and tissue inhibitors of metalloproteinase (TIMP)-1 were analysed by immunohistochemistry and Western blotting. The inducibility and duration of AF were measured by atrial burst pacing.

KEY RESULTS

After atrial pacing, the proportion of TUNEL positive cells, myolysis, atrial fibrosis and dilatation were all significantly increased and these changes were inhibited by spironolactone. Spironolactone treatment reversed the increased expression of caspase-3, bax, calpain I and MMP-9 and the decreased level of Bcl-2, calpastatin and TIMP-1, induced by chronic atrial pacing. Also spironolactone prevented the increased inducibility and duration of AF, induced by tachypacing.

CONCLUSIONS AND IMPLICATIONS

Treatment with spironolactone prevented myocardial apoptosis, myolysis, atrial fibrosis and dilatation, suggesting a possible beneficial effect of aldosterone antagonism on atrial structural remodelling in AF.

Stability of Estrogen Receptor and HER2 Status Following Trastuzumab and Polychemotherapy Regimen

Background: ER and HER2 status are important to determine a patient's eligibility to receive endocrine therapy and anti-HER2 (trastuzumab) therapy, respectively. However, whether the status of ER and HER2 is stable after administration of trastuzumab and chemotherapy remains controversial. To date, there have been rare studies describing a change of ER and HER2 status following such treatment. We herein examined our experience to further elucidate this issue.Material and methods: Our study included 24 patients who had been diagnosed with breast cancer from 12/1996 to 1/2005 with known ER and HER2 status in both primary and paired relapse tumors (9 distant and 15 locoregional). All of the patients had HER2-positive primary carcinoma and had been treated with trastuzumab administered concomitantly or after polychemotherapy. Fifteen patients had ER-positive primary carcinomas. ER status was defined as positive if ≥10% of tumor cells demonstrated nuclear staining by immunstaining. HER2 status was defined as positive if an immunostaining demonstrated 3+ staining and/or FISH demonstrated a HER2:CEP17 gene copy ratio ≥2.0. The receptor status was tested on tissue sections (for primary tumors) or on FNA samples (for metastases). We evaluated the agreement of ER and HER2 status between primary breast carcinomas and paired metastatic tumors.Results: The time elapsed between the diagnosis of the primary breast carcinoma and sampling of the paired metastatic tumor was &gt;24 months for all patients but one (mean interval, 75 months). Before the metastatic tumors were sampled, the duration of trastuzumab therapy had been ≥12 month in 18 patients; in some patients the treatment had been intermittent. All 15 patients with ER-positive primary carcinoma had received adjuvant endocrine therapy, including tamoxifen, aromatase inhibitor or both, and 7 of them had completed 5 years of treatment. ER status of primary and metastatic tumors agreed in 20 of the 24 patients, with a concordance rate of 83.3% (95% CI, 68.42% - 98.24%), and Cohen's kappa coefficient of 0.6596 (95% CI, 0.3598 - 0.9593). Of the four patients with discordant ER status, three had ER-positive primary tumors but ER-negative metastatic tumors, and one had ER-negative primary tumor but ER-positive metastatic tumor. Notably, in two of the four patients, the percentage of ER-positive tumor cells in the primary carcinomas was close to the cutoff (10%), indicating the potential of scoring difficulty. Negative HER2 status was found in three (12.5%) of the 24 metastatic tumors. One of the three patients had two primary carcinoma nodules: one HER2-positive and the other HER2 negative. It is possible that negative HER2 status in the metastatic tumor may result from a metastasis from the HER2-negative primary tumor, rather than a true discrepancy.Conclusions: Change in ER status was found in 17% relapse tumors, mostly from positive to negative. Converting HER2 status from positive to negative was seen in 13% patients. Overall, trastuzumab and chemotherapy do not significantly alter ER and HER2 status. However, a larger study is required to confirm whether the discordant receptor status is due to true biologic shift or other factors (i.e., technical and interpretation variation).

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5097.