The PP2A-Aβ gene is regulated by multiple transcriptional factors including Ets-1, SP1/SP3, and RXRα/β

Protein phosphatase-2A (PP-2A) is a major serine/threonine phosphatase abundantly expressed in eukaryotes. PP-2A is a heterotrimer that contains a 65 kD scaffold A subunit, a 36 kD catalytic C subunit, and a regulatory B subunit of variable isoforms ranging from 54-130 kDs. The scaffold subunits, PP2A-Aα/β, act as platforms for both the C and B subunits to bind, and thus are key structural components for PP-2A activity. Mutations in both genes encoding PP2A-Aα and PP2A-Aβ lead to carcinogenesis and likely other human diseases. Our previous work showed that the gene coding for PP2A-Aα is positively regulated by multiple transcription factors including Ets-1, CREB, and AP-2α but negatively regulated by SP-1/SP-3. In the present study, we have functionally dissected the promoter of the mouse PP2A-Aβ gene. Our results demonstrate that three major cis-elements, including the binding sites for Ets-1, SP1/SP3, and RXRα/β, are present in the proximal promoter of the mouse PP2A-Aβ gene. Gel mobility shifting assays reveal that Ets-1, SP1/SP3, and RXRα/β all bind to PP2A-Aβ gene promoter. In vitro mutagenesis and reporter gene activity assays demonstrate that while Ets-1 displays negative regulation, SP1/SP3 and RXRα/β positively regulate the promoter of the PP2A-Aβ gene. Co-expression of the cDNAs encoding Ets-1, SP1/SP3, or RXRα/β and the luciferase reporter gene driven by PP2A-Aβ promoter further confirm their control over the PP2A-Aβ promoter. Finally, ChIP assays demonstrate that Ets-1, SP1/SP3, and RXRα/β can all bind to the PP2A-Aβ gene promoter. Together, our results reveal that multiple transcription factors regulate the PP2A-Aβ gene. Moreover, our results provide important information explaining why PP2A-Aα and PP2A-Aβ display distinct expression levels.

Blind source separation in characterizing ECG pre-shock waveforms during Ventricular Fibrillation

Ventricular Fibrillation (VF) is a cardiac arrhythmia for which the only available treatment option is defibrillation by electrical shock. Existing literature indicates that VF could be the manifestation of different sources controlling the heart with different degrees of organization. In this work we test the hypothesis that the pre-shock waveforms of successful and unsuccessful shock outcomes could be related to the number of independent sources present in these waveforms. The proposed method uses Blind Source Separation (BSS) to extract independent components in frequency direction from a pig database consisting of 20 pre-shock waveforms. The slope of the energy capture curve was used as an indicator to demonstrate the number of independent sources required to model the pre-shock waveforms. The results were also quantified by performing a linear discriminant analysis based classification achieving an overall classification accuracy of 75%. The results indicate that successful cases can be modeled with less number of independent sources compared to unsuccessful cases.

Abstract P6-11-01: Intermittent High Dose Proton Pump Inhibitor Improves Progression Free Survival as Compared to Standard Chemotherapy in the First Line Treatment of Patients with Metastatic Breast Cancer

Purpose: High dose proton pump inhibitor (PPI) has proved to be potentially effective when combined with chemotherapy in preclinical data. This study (NCT01069081) was designed to investigate whether the efficacy of chemotherapy could be improved with the addition of proton pump inhibitor (PPI) in patients with metastatic breast cancer.

Patients and Methods: Females elder than 18 years old with histologically confirmed metastatic breast cancer were eligible for participation. Patients enrolled were randomly assigned to three arms: Arm A, docetaxol 75 mg/m2 on d4, followed by cisplatin 75 mg/m2 on d4, repeated every 21 days until maxinum 6 cycles or presence of disease progression or intolerable toxicity; Arm B, the same chemotherapy plus esomeprazole 80 mg p.o. bid three days on and the subsequent four days off, beginning on d1 repeated weekly up to disease progression, intolerable toxicity, patient's withdrawal, or a maximum of 66 weeks; Arm C, the same as Arm B with the only difference being dose of esomeprazole at 100 mg p.o. bid. The primary endpoint was progression free survival (PFS), and the secondary endpoints were time to progression (TTP), objective response rate (ORR), safety profile, and overall survival (OS).

Results: From Aug. 2009 to Dec. 2011, 100 women signed informed consent form (ICF) and 94 patients have undergone at least one injection of chemotherapy. Three patients had severe hypersensitivity reactions, two occurring after the first injection of docetaxol and one in the second cycle. After a median follow up of 17 months, 68 (72.3%) patients got disease progression and 23 (24.5%) patients died. Median PFS for the whole group (n = 94), arm A (n = 33), arm B (n = 30), arm C (n = 31) were 8.9, 7.5, 10.9, and 9.5 months, respectively (p = 0.082). A significant difference was observed between patients who had taken PPI and who not with median PFS of 9.5 and 7.5 months, respectively (p = 0.030). Among 17 patients with triple negative breast cancer, this difference was bigger with median PFS of 9.5 and 3.3 months, respectively (p = 0.014). The overall response rates for the whole group, arm A, arm B, arm C were 58.5%, 51.5%, 63.3%, 61.3%, respectively.

Conclusion: This trial is the first randomized study to demonstrate antitumor effects of intermittent high dose PPI in patients with metastatic breast cancer. Docetaxel and cisplatin doublet is comparable to the other first-line chemotherapeutical regimens and the addition of proton pump inhibitor to the doublet improves efficacy with no adding toxicity, especially in patients with triple negative breast cancer.

Key Words Proton Pump Inhibitor (PPI), Triple Negative Breast Cancer (TNBC), Phase II Study, Metastatic Breast Cancer, Chemotherapy

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-11-01.

LXRβ activation increases intestinal cholesterol absorption, leading to an atherogenic lipoprotein profile

OBJECTIVES

Liver X receptors (LXRs) are essential for the regulation of intestinal cholesterol absorption. Because two isoforms exist, LXRα and LXRβ, with overlapping but not identical functions, we investigated whether LXRα and LXRβ exert different effects on intestinal cholesterol absorption.

DESIGN

Wild-type (WT), LXRα(-/-) and LXRβ(-/-) mice were fed control diet, 0.2% cholesterol-enriched diet or 0.2% cholesterol-enriched diet plus the LXR agonist GW3965.

RESULTS

When fed a control diet, all three genotypes showed similar levels of cholesterol absorption. Of interest, a significant increase in cholesterol absorption was found in the LXRα(-/-) mice, but not in the WT or LXRβ(-/-) animals, when fed a diet enriched with 0.2% cholesterol or 0.2% cholesterol + GW3965. Reduced faecal neutral sterol excretion and a hydrophobic bile acid profile were also observed in LXRα(-/-) mice. Greater increases in the apolipoprotein (apo)B-containing lipoproteins in serum were seen in the LXRα(-/-) mice. A 0.2% cholesterol +GW3965 diet suppressed intestinal Npc1l1 protein expression to the same extent for all genotypes, while Abca1 and Abcg5 were elevated to the same degree.

CONCLUSIONS

In the intestine, LXRα and LXRβ seem to exert similar effects on expression of cholesterol-transporting proteins such as Npc1l1. Selective activation of LXRβ may generate effects such as increased cholesterol absorption and elevated serum levels of apoB-containing lipoproteins, which seem to be counteracted by LXRα. Therefore, an intestinal LXRβ-specific pathway might exist in terms of cholesterol transportation in addition to the main pathway.

Neoadjuvant HIFU treatment for malignant fibrous histiocytoma: report of a case

High-intensity focused ultrasound (HIFU) is an innovative, noninvasive, extracorporeal technique that induces coagulative necrosis of tumor tissue by thermal effects and cavitation. In published studies, HIFU has usually been used as an alternative to surgery, with or without other treatment modalities, to achieve curative tumor ablation or palliative tumor cytoreduction. Neoadjuvant HIFU treatment for primary inoperable malignant fibrous histiocytoma has never been reported, and neoadjuvant radiotherapy, chemoradiation, or chemotherapy is routinely under consideration. This is the first case in which HIFU ablation contributed as a neoadjuvant therapy to facilitate function-sparing resection, not as a replacement for surgery. It suggests that HIFU ablation may have some unique major advantages for treating inoperable huge soft-tissue sarcomas as a neoadjuvant local treatment modality, especially for patients for whom neoadjuvant chemotherapy or radiotherapy is not indicated.

Large-scale homogeneously distributed Ag-NPs with sub-10 nm gaps assembled on a two-layered honeycomb-like TiO2 film as sensitive and reproducible SERS substrates

We present a surface-enhanced Raman scattering (SERS) substrate featured by large-scale homogeneously distributed Ag nanoparticles (Ag-NPs) with sub-10 nm gaps assembled on a two-layered honeycomb-like TiO(2) film. The two-layered honeycomb-like TiO(2) film was achieved by a two-step anodization of pure Ti foil, with its upper layer consisting of hexagonally arranged shallow nano-bowls of 160 nm in diameter, and the lower layer consisting of arrays of about fifty vertically aligned sub-20 nm diameter nanopores. The shallow nano-bowls in the upper layer divide the whole TiO(2) film into regularly arranged arrays of uniform hexagonal nano-cells, leading to a similar distribution pattern for the ion-sputtered Ag-NPs in each nano-cell. The lower layer with sub-20 nm diameter nanopores prevents the aggregation of the sputtered Ag-NPs, so that the Ag-NPs can get much closer with gaps in the sub-10 nm range. Therefore, large-scale high-density and quasi-ordered sub-10 nm gaps between the adjacent Ag-NPs were achieved, which ensures homogeneously distributed 'hot spots' over a large area for the SERS effect. Moreover, the honeycomb-like structure can also facilitate the capture of target analyte molecules. As expected, the SERS substrate exhibits an excellent SERS effect with high sensitivity and reproducibility. As an example, the SERS substrate was utilized to detect polychlorinated biphenyls (PCBs, a kind of persistent organic pollutants as global environmental hazard) such as 3,3',4,4'-pentachlorobiphenyl (PCB-77) with concentrations down to 10(-9) M. Therefore the large-scale Ag-NPs with sub-10 nm gaps assembled on the two-layered honeycomb-like TiO (2) film have potentials in SERS-based rapid trace detection of PCBs.

A primary proteomic analysis of serum from patients with nonfunctioning pituitary adenoma

OBJECTIVE

The early diagnosis of nonfunctioning pituitary adenoma (NFPA) is difficult. The objective of this study was to find specific protein biomarkers to aid in the early detection of NFPA.

METHODS

Serum samples from 34 patients with NFPA and 34 age- and sex-matched healthy control subjects were analysed using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) technology. The spectra were generated, protein peak clustering was performed and classification analyses were carried out using a decision tree classification algorithm.

RESULTS

Nine differentially expressed serum proteins were identified in the patients with NFPA compared with the control subjects. Both the sensitivity and specificity of the decision tree classification algorithm were 82.4% for NFPA.

CONCLUSIONS

Nine new serum protein biomarkers for NFPA were identified. SELDI-TOF-MS coupled with data mining tools might provide a novel approach for the early diagnosis of NFPA and population screening for the disease.

Candida albicans survival and biofilm formation under starvation conditions

AIM

To investigate the survival and biofilm formation capacity of Candida albicans in starvation and under anaerobic conditions.

METHODOLOGY

Candida albicans growth and survival were monitored in vitro for up to 8 months. Fungal suspensions from late exponential, stationary and starvation phases were incubated on human dentine, polystyrene and glass slides. Scanning electron microscopy (SEM) was used to observe the process of biofilm formation. 2,3-bis(2-Methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxyanilide inner salt (XTT) reduction assay was performed to quantify the biofilm formation capability, and confocal laser scanning microscopy (CLSM) was used to study and make semi-quantitative comparisons of the ultrastructure of biofilms formed on human dentine. 'XTT bioactivity' and 'COMSTAT results' were analysed by two-way analysis of variance (ANOVA) and one-way ANOVA, respectively.

RESULTS

Candida albicans survived for over six months. SEM demonstrated that starving C. albicans produced mature biofilms on different substrata. C. albicans of the same growth phase incubated on human dentine displayed significantly higher biofilm formation capability than on polystyrene or glass slides (P < 0.05). Biofilm formation capability by starving cells was significantly lower than that in exponential or stationary phases (P < 0.05). CLSM revealed that biofilms formed by starvation-phase cells were less complex, had a higher roughness coefficient and surface/volume ratio (P < 0.05).

CONCLUSIONS

Candida albicans cells can survive and form biofilms in anaerobic and nutrient-limited conditions and may pose a treatment challenge.

WE-C-217BCD-05: A Novel Interpolation Method for the 3D Reconstruction of Cell Structures

PURPOSE

To develop a new interpolation method for accurate 3D reconstruction of cell morphology from laser scanning confocal microscope (LSCM) image data.

METHODS

Current techniques are based on the assumption that pixel intensity or contour shapes of images change linearly in the interpolation direction. Gray-value and position of the pixel in interpolated image slice are obtained through weighted average calculation with gray-values and distances of corresponding pixels in two adjacent original image slices, only information from adjacent image slices is considered, often fail to meet the need of 3D reconstruction for cells because of the complex cell morphology. The new method interpolates cellular organelle contours in polar coordinate system. Coordinate system origin is chosen to be the mass center weighted by pixel intensity instead of conventional geometric center, contour points of the organelle is sampled by their angles first and fitted with uniform cubic B-spline to perform interpolation. For complex organelle structures such as branched nuclei, a special method combining morphological information and corner detection technique based on curvature scale space has been developed to solve the contour division and related problems. New method was applied to confocal images of 130 different cells acquired with an LSCM system (LSM510, Zeiss), sampling step was set as 0.5 μm in longitudinal direction, pixel size in horizontal plane was 0.07 μm and the resolution was 512×512. Marching cubes algorithm was used for 3D reconstruction.

RESULTS

Experiments showed that reconstructed 3D images with new method have much smoother and more valid organelle surfaces for both cytoplasm and nucleus than those from conventional methods.

CONCLUSIONS

The new interpolation method can significantly improve the quality of 3D reconstruction and serve as a valid and effective tool for quantitative study of 3D cell morphology in radiation biology and other areas of life science.*support by NSFC- 81171342. Supported by the National Science Foundation of China (NSFC- 81171342).

Aligned silk-based 3-D architectures for contact guidance in tissue engineering

An important challenge in the biomaterials field is to mimic the structure of functional tissues via cell and extracellular matrix (ECM) alignment and anisotropy. Toward this goal, silk-based scaffolds resembling bone lamellar structure were developed using a freeze-drying technique. The structure could be controlled directly by solute concentration and freezing parameters, resulting in lamellar scaffolds with regular morphology. Different post-treatments, such as methanol, water annealing and steam sterilization, were investigated to induce water stability. The resulting structures exhibited significant differences in terms of morphological integrity, structure and mechanical properties. The lamellar thicknesses were ∼2.6 μm for the methanol-treated scaffolds and ∼5.8 μm for water-annealed. These values are in the range of those reported for human lamellar bone. Human bone marrow-derived mesenchymal stem cells (hMSC) were seeded on these silk fibroin lamellar scaffolds and grown under osteogenic conditions to assess the effect of the microstructure on cell behavior. Collagen in the newly deposited ECM was found aligned along the lamellar architectures. In the case of methanol-treated lamellar structures, the hMSC were able to migrate into the interior of the scaffolds, producing a multilamellar hybrid construct. The present morphology constitutes a useful pattern onto which hMSC cells attach and proliferate for guided formation of a highly oriented extracellular matrix.

Hyaluronan tetrasaccharide in the cerebrospinal fluid is associated with self-repair of rats after chronic spinal cord compression

The objective of this study was to explore changes in hyaluronan levels in the cerebrospinal fluid (CSF) in a spinal cord compression model, to investigate whether hyaluronan tetrasaccharide was involved in this process, and to test the effects of hyaluronan tetrasaccharide on neuron and oligodendrocyte repair. We developed a chronic spinal cord compression model with various sizes of polymer sheets (1.5×0.7×0.3 mm(3); 5×1.5×0.7 mm(3)) that were implanted microsurgically underneath the C(5-6) laminae. The rats were divided into three groups: a sham group, a mildly compressed (MC) group, and a widely compressed (WC) group. Locomotor functional evaluations revealed that the behavioral function of the MC and WC groups dropped to their lowest level from the fourth to fifth week and gradually recovered thereafter. The hyaluronan levels in the CSF gradually increased after spinal cord compression. Furthermore, hyaluronan tetrasaccharide was involved in the hyaluronan change. In addition, we found that nuclear factor kappa B (NF-κB) and cellular inhibitor-of-apoptosis protein 2 (c-IAP(2)) were co-expressed in neurons and oligodendrocytes, and caspase-3 expression gradually decreased in the compression model. The brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) expression was upregulated in astrocytes at the fourth week post-compression. Hyaluronan tetrasaccharide (HA(4)) induced NF-κB and c-IAP(2) to suppress the H(2)O(2)-induced apoptosis in primary neuronal cultures and increased BDNF and VEGF expression in astrocytic cultures in vitro. These findings suggest that HA(4) in the CSF may associate with behavioral recovery by increasing the levels of NF-κB, c-IAP(2), and neurotrophic factors after chronic spinal cord compression.

Randomized phase II non-inferiority study (NO16853) of two different doses of capecitabine in combination with docetaxel for locally advanced/metastatic breast cancer

BACKGROUND

This phase II study investigated whether a lower-than-approved dose of capecitabine, plus docetaxel (XT), would improve tolerability versus standard-dose XT without compromising efficacy.

PATIENTS AND METHODS

Women aged ≥18 years with locally advanced/metastatic breast cancer resistant to anthracycline-based chemotherapy in the (neo)adjuvant, first- or second-line metastatic setting were eligible. Patients were randomly assigned to receive standard-dose XT (capecitabine 1250 mg/m(2) twice daily, days 1-14; docetaxel 75 mg/m(2), day 1 every 3 weeks) or low-dose XT (capecitabine 825 mg/m(2) twice daily, days 1-14; docetaxel as above). The primary objective was to demonstrate non-inferiority of low-dose to standard-dose XT in terms of progression-free survival (PFS).

RESULTS

470 patients were randomly allocated in a 1 : 1 ratio to standard-dose or low-dose XT. Median PFS was 7.9 versus 5.8 months [hazard ratio 1.16, 95% confidence interval (CI) 0.95-1.43] in the standard-dose and low-dose arms, respectively. The upper limit of the 95% CI was above the predefined non-inferiority margin (1.35, P = 0.078). Secondary efficacy end points were consistent with PFS. The frequency and severity of adverse events was similar in both treatment arms.

CONCLUSIONS

Non-inferiority of low-dose to standard-dose XT in terms of PFS was not demonstrated; this may be due to regional subgroup effects.