White matter integrity correlates with choline level in dorsal anterior cingulate cortex of obsessive compulsive disorder patients: A combined DTI-MRS study

Structural and functional neuroimaging studies have indicated that the cortico-striato -thalamo-cortical (CSTC) circuit contributes to the pathophysiology of obsessive compulsive disorder (OCD). As an essential component of CSTC circuit, the dorsal anterior cingulate cortex (dACC) plays an important role for its advanced function in cognition and emotion control. A comprehensive understanding of the dACC disruption in OCD pathological mechanism is desired. In this study, we performed a combined diffusion tensor imaging (DTI) and magnetic resonance spectroscopy (MRS) study in 15 OCD patients and 15 healthy controls to investigate the association between structural abnormality and metabolic alterations within the dACC area. We found a positive correlation between the dACC fractional anisotropy (FA) value and choline concentration in patients. Moreover, the FA was positively associated with OCD clinical symptom, especially the compulsive behavior, which showed the clinical relevance of dACC white matter integrity in OCD. To our knowledge, the present work is the first combined DTI-MRS study of OCD. Our findings demonstrated the co-occurrence of structural and metabolic changes within dACC in OCD patients. It was suggested that the disrupted white matter integrity might be accompanied with degraded cellular membrane turnover.

Spontaneous neuronal activity in insula predicts symptom severity of unmedicated obsessive compulsive disorder adults

Emerging evidence has suggested that the pathophysiology of obsessive compulsive disorder (OCD) might involve widely distributed large-scale brain systems. The dysfunction within salience network, which is comprised of dorsal anterior cingulated cortex (dACC) and bilateral insular areas, has been proposed to contribute to OCD onset. The mechanism underlying salience network abnormality remains unclear and it is worthwhile to investigate its clinical relevance using functional neuroimaging approaches. In this study, we performed the spontaneous brain activity measurement using resting-state functional magnetic resonance imaging (fMRI) on unmedicated OCD patients (n=23). Specifically, the amplitude of low frequency (0.01-0.08 Hz) fluctuations (ALFF) was calculated for regions in salience network. The voxel-based Pearson's correlative analysis was conducted to explore the relationship beween ALFF measures and symptom severity for OCD patients. The results showed that the spontaneous neuronal activity in insula was significantly correlated to OCD clinical symptoms, especially compulsive behaviors. Our findings consolidated that the salience network played an important role in the pathogenesis of OCD and the intensity of intrinsic brain activity in insula provided a predictive biomarker for OCD symptom severity.

Scanning tunneling microscopy study of the possible topological surface states in BiTeCl

Recently, the non-centrosymmetric bismuth tellurohalides such as BiTeCl are being studied as possible candidates for topological insulators. While some photoemission studies showed that BiTeCl is an inversion asymmetric topological insulator, others showed that it is a normal semiconductor with Rashba splitting. Meanwhile, first-principle calculations have failed to confirm the existence of topological surface states in BiTeCl so far. Therefore, the topological nature of BiTeCl requires further investigation. Here we report a low-temperature scanning tunneling microscopy study on the surface states of BiTeCl single crystals. On the tellurium (Te) -terminated surfaces with relatively low defect density, evidence for topological surface states is observed in the quasi-particle interference patterns, both in the anisotropy of the scattering vectors and the fast decay of the interference near the step edges. Meanwhile, on the samples with much higher defect densities, we observed surface states that behave differently. Our results may help to resolve the current controversy on the topological nature of BiTeCl.

Annexin A2 is implicated in multi-drug-resistance in gastric cancer through p38MAPK and AKT pathway

Studies have shown that Annexin A2 (ANXA2) is related with tumor proliferation, apoptosis, differentiation, invasion, migration, and drug resistance. The purpose of this study was to investigate the role and its mechanisms of ANXA2 in multi-drug-resistance (MDR) in gastric cancer. ANXA2 expression in both gastric cancer tissues and cell lines were detected by quantitative real-time PCR (RT-qPCR) and Western blotting. The cell proliferation was measured by SRB assay. The pool of siRNA against ANXA2 was designed and synthesized and then transfected into resistant gastric cancer SGC7901/DDP cells. ANXA2 expression was detected by RT-qPCR and Western blotting. Drug sensitivities of SGC7901/DDP cells to P-gp-related drug (doxorubicin) and P-gp-non-related drugs (5-FU and cisplatin) were measured by SRB assay. Expression of MDR-related genes and phosphorylation of AKT and MAPKs were also detected by RT-qPCR and Western blotting. Results showed that ANXA2 expression was significantly higher in gastric specimens than that in normal tissues, and negatively correlated with the differentiation level of gastric cancer. In addition, ANXA2 expression level was higher in SGC7901/DDP cells than that in parent SGC7901 cells. After knock-down ANXA2 expression using ANXA2 small interfering RNA, the drug sensitivity of SGC7901/DDP cells to doxorubicin, 5-FU and DDP increased. Delivery of ANXA2 siRNA significantly downregulated the expression of P-gp, MRP1 and Bcl-2, while markedly upregulated Bax in SGC7901/DDP cells. However, several other MDR factors such as GST-π, TOPO-I and TOPO-II had no obvious changes. Additionally, phosphorylation of P38MAPK and AKT, but not ERK1/2 or JNKs was specifically decreased in SGC7901/DDP cells after ANXA2 siRNA delivery. Importantly, P38MAPK and AKT inhibitor increased the drug sensitivity of SGC701/DDP cells in a similar way as ANXA2 siRNAs does. ANXA2 is involved in gastric cancer MDR through regulating p38MAPK and AKT pathways as well as certain MDR factors.

Malondialdehyde and SOD-induced changes of gastric tissues in acute gastric mucosal injury under positive acceleration

The aim of this study was to investigate the impacts of positive acceleration (+Gz) on the gastric mucosal tissues in cases of acute gastric mucosal injury and to explore the role of oxygen free radicals. Thirty Sprague Dawley rats were randomly divided into the absolute ethanol control group (A group), absolute ethanol +5Gz group (B group), absolute ethanol +10Gz group (C group). Following centrifugation, the gastric tissues of each group were studied for the presence of gastric mucosal injuries and morphological changes. The concentrations of malondialdehyde (MDA) and superoxide dismutase (SOD) contents were simultaneously investigated. Degree of gastric mucosal injuries were as follows: C group (visually 49.080 ± 10.254, under light microscopy 9.400 ± 2.011) > B group (visually 23.654 ± 9.678, under light microscopy 5.000 ± 1.054) > A group (visually 11.410 ± 3.742, under light microscopy 3.800 ± 1.399). The gastric mucosal MDA content (0.376 ± 0.084 vs 0.235 ± 0.044) was significantly higher in the C group than in the A group, whereas the SOD content (8.852 ± 1.001 vs 10.694 ± 0.965) was lower than that in the A group. However, the MDA and SOD contents did not change much in the B group. Our results suggest that the +Gz exposure might aggravate the acute gastric mucosal injury, and changes in MDA and SOD contents in the gastric tissues indicated that the oxygen free radicals play an important role in this regard.

Effects of Herceptin on circulating tumor cells in HER2 positive early breast cancer

The objective of this study was to determine the changes in peripheral blood circulating tumor cells in HER2-positive early breast cancer before and after Herceptin therapy, and to explore the effects of the HER2 gene and Herceptin on circulating tumor cells. CK19 mRNA expression in peripheral blood was evaluated by qRT-PCR as an index of circulating tumor cells in 15 cases of HER-2-positive breast cancer and 18 cases of HER2-negative breast cancer before, and after chemotherapy as well. Ten cases of HER2-positive breast cancer continued on Herceptin therapy for 3 months after chemotherapy, and their peripheral blood was again drawn and assayed for CK-19 mRNA expression. Preoperatively, all cases of HER2-positive cancer were positive for CK19 mRNA in peripheral blood, but 6 cases of HER2-negative breast cancer were positive (33.3%), where there was a substantial difference between the two groups. After 6 cycles of adjuvant chemotherapy, CK19 positive rates in cases of HER2-positive and -negative breast cancer reduced by 93.3 and 11.1%, respectively, with a significant difference still existing. After 3 months of Herceptin therapy, expression of CK19 mRNA declined considerably in 10 cases of HER2 positive breast cancer (113.66 ± 88.65 vs 63.35 ± 49.27, P = 0.025). HER-2 gene expression closely correlated with circulating tumor cells in peripheral blood of early breast cancer patients. Moreover, Herceptin, a monoclonal antibody for HER2, can reduce the number of circulating tumor cells, which can be an early predictive factor for Herceptin therapy effectiveness against breast cancer.

Electronic structure of Eu(Fe0.79Ru0.21)2As2 studied by angle-resolved photoemission spectroscopy

Eu(Fe(0.79)Ru(0.21))2As2 is suggested to be a nodeless superconductor based on the empirical correlation between pnictogen height (hPn) and superconducting gap behavior, in contrast to BaFe2(As(0.7)P(0.3))2 and Ba(Fe(0.65)Ru(0.35))2As2. We studied the low-lying electronic structure of Eu(Fe(0.79)Ru(0.21))2As2 with angle-resolved photoemission spectroscopy (ARPES). By photon energy dependence and polarization dependence measurements, we resolved the band structure in the three-dimensional momentum space and determined the orbital character of each band. In particular, we found that the dz2 -originated ζ band does not contribute spectral weight to the Fermi surface around Z, unlike BaFe2(As(0.7)P(0.3))2 and Ba(Fe(0.65)Ru(0.35))2As2. Since BaFe2(As(0.7)P(0.3))2 and Ba(Fe(0.65)Ru(0.35))2As2 are nodal superconductors and their hPn's are less than 1.33 Å, while the hPn of Eu(Fe(0.79)Ru(0.21))2As2 is larger than 1.33 Å, our results provide more evidence for a direct relationship between nodes, dz2 orbital character and hPn. Our results help to provide an understanding of the nodal superconductivity in iron-based superconductors.

Role of IFN-ks, IFN-ks related genes and the DEPDC5 gene in Hepatitis B virus-related liver disease

Recent studies have associated genetic variation near the interleukin 28B (IL28B/IFN-λ3) gene with natural clearance of the hepatitis C virus (HCV) infection, and a common variant in the DEP domain containing 5 (DEPDC5) locus on chromosome 22 has been shown to affect susceptibility to hepatocellular carcinoma (HCC) in Japanese individuals with chronic HCV infection. This study was conducted to determine whether polymorphisms near or in interferon-lambda (IFN-λs) genes and their receptor genes such as interleukin 28 receptor, alpha (IL28RA) and interleukin 10 receptor, beta (IL10RB) as well as p21-activated kinases 4 (PAK4) and iron/zinc purple acid phosphatase-like protein (PAPL), which are locate upstream of IFN-λs, and lastly the DEPDC5 gene are associated with hepatitis B virus-related liver disease in Han Chinese. The study subjects included 507 normal healthy controls, 350 individuals with natural clearance of HBV and 792 HBV-infected patients. The patients were categorized into 157 inactive carriers (Case I), 216 active carriers (Case II), 111 cirrhotics (Case III) and 308 HCC patients (Case IV) subgroups. Seven single nucleotide polymorphisms (SNPs) were genotyped using the Matrix-assisted Laser Desorption/Ionisation mass spectrometric (MALDI-TOF MS) SNP genotyping assay. Rs423058 upstream of PAPL, rs2834167 in IL10RB and rs1012068 in DEPDC5 were associated with chronic HBV status, HBV natural clearance and the presence of HCC (P = 0.0004–0.024), respectively. PAPL, IL10RB and DEPDC5 polymorphisms have an impact on progression of HBV-related liver disease. However, IFN-λs genes as a tool to differentiate between different clinical courses of HBV infection were not useful in the Han Chinese population.

Abstract P4-15-08: Discovery of a potent inhibitor of CREB-mediated gene transcription that completely suppresses the growth of triple-negative breast cancer cells

Background: Breast cancers are a heterogeneous group of diseases with distinct and complex mechanisms of pathogenesis. Triple-negative breast cancers (TNBC) form a subgroup of breast cancers with poor prognosis. TNBCs lack the expression of estrogen receptor (ER), progesterone receptor (PR) or HER2 and no targeted therapies exist. The cyclic-AMP (cAMP) response element binding protein (CREB) is a stimulus-induced transcription factor activated by multiple extracellular signals through phosphorylation. The transcription activity of CREB depends on its phosphorylation at Ser133 by mitogen- and stress-activated protein serine/threonine kinases, which are often dysregulated in TNBCs. The phosphorylated CREB (p-CREB) can then bind the mammalian transcription co-activator, CREB-binding protein (CBP), via the kinase-inducible domain (KID) in CREB and KID-interacting (KIX) domain in CBP. This binding event will further recruit other transcriptional machinery to the gene promoter to initiate CREB-dependent gene transcription. CREB is overexpressed in breast cancer tissues compared to normal mammary tissues and the level of expression inversely correlates with disease-free survival. Genetic studies have shown that inhibition of CREB's activity leads to decreased breast cancer cell proliferation. We describe here the discovery of a potent small molecule inhibitor of CREB-mediated gene transcription with in vitro and in vivo activity in TNBCs.

Methods: The small molecule inhibitor (compound 1) was reporter earlier by us (Li and Xiao ChemBioChem 2009). Starting from this lead compound, we designed and synthesized a more potent compound 2. The in vitro antiproliferative activity and apoptosis induction were evaluated in MDA-MB-231 and MDA-MB-468 cells with MTT assays and flow cytometry, respectively. In vivo activity was investigated in a human xenograft model of MDA-MB-468. The CREB target gene expression was investigated by Western blot and qRT-PCR analysis.

Results: Starting from compound 1, which is a low micromolar and cell-permeable inhibitor of CREB-mediated gene transcription, we designed and synthesized compound 2. Compound 2 potently inhibited CREB-mediated gene transcription with IC50 ∼80 nM. In vitro, this compound inhibited proliferation of MDA-MB-231 and MDA-MB-468 cells with concomitant activation of apoptosis and necrosis. In contrast, compound 2 was not toxic to normal human mammary epithelial cells. In vivo, compound 2 completely suppressed the growth of MDA-MB-468 cells at a dose not toxic to the mice.

Conclusion: Compound 2 potently inhibited CREB-mediated gene transcription and TNBC cell growth in vitro and in vivo. These results suggest that CREB is a promising druggable target for TNBCs.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-15-08.

Mycobacterium tuberculosis MPT64 stimulates the activation of murine macrophage modulated by IFN-γ

BACKGROUND AND AIMS

MPT64, a major target of cell-mediated immunity in tuberculosis, is proposed to be a promising candidate for novel vaccines and diagnostic tests; it also involves in virulence mechanism of Mycobacterium tuberculosis. In this study, we investigated the effect of MPT64 on activation of RAW264.7 macrophage, and explored the possible mechanism.

MATERIALS AND METHODS

MPT64 protein was prepared by cloning, expression and purification from Escherichia (E.) coli. Cytokines (IL-1β, IL-6, IL-10 and TNF-α) expression in RAW264.7 macrophage induced by MPT64 was evaluated by xMAP technology. Cell counting kit (CCK8) assay was employed to detect the viability of MPT64-treated macrophage; moreover, flow cytometric analysis and Western Blot analysis were used to measure the effect of MPT64 on apoptosis in macrophage and cleaved caspase-3 expression respectively.

RESULTS

MPT64 significantly promoted the levels of IL-1β, IL-6, IL-10 and TNF-α; pretreatment of MPT64 followed by IFN-γ stimulation further up-regulated IL-6 production (p < 0.01, compared with MPT64-treated group). In CCK8 assay, significantly increased absorbance of MPT64-treated macrophage suggested that cell viability might be enhanced. Additionally, MPT64 modulated the apoptosis of RAW264.7 macrophage partly through caspase-3 pathway.

CONCLUSIONS

MPT64 activated RAW264.7 macrophage to secrete IL-1β, IL-6, IL-10 and TNF-α; it might down-regulate apoptosis of macrophage partially via caspase-3 pathway. Furthermore, the effect of MPT64 on RAW264.7 macrophage could be modulated by IFN-γ, and co-stimulation of MPT64 with IFN-γ was conducive to the host immune, which might be applied for vaccine design and provide a reference for the treatment of tuberculosis.