Showing papers by "Sun Yat-sen University published in 2010"

The sequence and de novo assembly of the giant panda genome

Abstract: Using next-generation sequencing technology alone, we have successfully generated and assembled a draft sequence of the giant panda genome. The assembled contigs (2.25 gigabases (Gb)) cover approximately 94% of the whole genome, and the remaining gaps (0.05 Gb) seem to contain carnivore-specific repeats and tandem repeats. Comparisons with the dog and human showed that the panda genome has a lower divergence rate. The assessment of panda genes potentially underlying some of its unique traits indicated that its bamboo diet might be more dependent on its gut microbiome than its own genetic composition. We also identified more than 2.7 million heterozygous single nucleotide polymorphisms in the diploid genome. Our data and analyses provide a foundation for promoting mammalian genetic research, and demonstrate the feasibility for using next-generation sequencing technologies for accurate, cost-effective and rapid de novo assembly of large eukaryotic genomes.

Biological Activities of Polyphenols from Grapes

Abstract: The dietary consumption of grape and its products is associated with a lower incidence of degenerative diseases such as cardiovascular disease and certain types of cancers. Most recent interest has focused on the bioactive phenolic compounds in grape. Anthocyanins, flavanols, flavonols and resveratrol are the most important grape polyphenols because they possess many biological activities, such as antioxidant, cardioprotective, anticancer, anti-inflammation, antiaging and antimicrobial properties. This review summarizes current knowledge on the bioactivities of grape phenolics. The extraction, isolation and identification methods of polyphenols from grape as well as their bioavailability and potential toxicity also are included.

Comparison of tocilizumab monotherapy versus methotrexate monotherapy in patients with moderate to severe rheumatoid arthritis: The AMBITION study

Abstract: Background: The anti-interleukin (IL) 6 receptor antibody tocilizumab inhibits signalling of IL6, a key cytokine in rheumatoid arthritis (RA) pathogenesis. Objective: To evaluate through the AMBITION study the efficacy and safety of tocilizumab monotherapy versus methotrexate in patients with active RA for whom previous treatment with methotrexate/biological agents had not failed. Methods: This 24-week, double-blind, double-dummy, parallel-group study, randomised 673 patients to either tocilizumab 8 mg/kg every 4 weeks, or methotrexate, starting at 7.5 mg/week and titrated to 20 mg/week within 8 weeks, or placebo for 8 weeks followed by tocilizumab 8 mg/kg. The primary end point was the proportion of patients achieving American College of Rheumatology (ACR) 20 response at week 24. Results: The intention-to-treat analysis demonstrated that tocilizumab was better than methotrexate treatment with a higher ACR20 response (69.9 vs 52.5%; p 3×– Conclusion: Tocilizumab monotherapy is better than methotrexate monotherapy, with rapid improvement in RA signs and symptoms, and a favourable benefit–risk, in patients for whom treatment with methotrexate or biological agents has not previously failed. Trial registration number: NCT00109408

Observation of a centrality-dependent dijet asymmetry in lead-lead collisions at √sNN=2.76 Tev with the ATLAS detector at the LHC

Abstract: By using the ATLAS detector, observations have been made of a centrality-dependent dijet asymmetry in the collisions of lead ions at the Large Hadron Collider. In a sample of lead-lead events with a per-nucleon center of mass energy of 2.76 TeV, selected with a minimum bias trigger, jets are reconstructed in fine-grained, longitudinally segmented electromagnetic and hadronic calorimeters. The transverse energies of dijets in opposite hemispheres are observed to become systematically more unbalanced with increasing event centrality leading to a large number of events which contain highly asymmetric dijets. This is the first observation of an enhancement of events with such large dijet asymmetries, not observed in proton-proton collisions, which may point to an interpretation in terms of strong jet energy loss in a hot, dense medium.

Edge Adaptive Image Steganography Based on LSB Matching Revisited

Abstract: The least-significant-bit (LSB)-based approach is a popular type of steganographic algorithms in the spatial domain. However, we find that in most existing approaches, the choice of embedding positions within a cover image mainly depends on a pseudorandom number generator without considering the relationship between the image content itself and the size of the secret message. Thus the smooth/flat regions in the cover images will inevitably be contaminated after data hiding even at a low embedding rate, and this will lead to poor visual quality and low security based on our analysis and extensive experiments, especially for those images with many smooth regions. In this paper, we expand the LSB matching revisited image steganography and propose an edge adaptive scheme which can select the embedding regions according to the size of secret message and the difference between two consecutive pixels in the cover image. For lower embedding rates, only sharper edge regions are used while keeping the other smoother regions as they are. When the embedding rate increases, more edge regions can be released adaptively for data hiding by adjusting just a few parameters. The experimental results evaluated on 6000 natural images with three specific and four universal steganalytic algorithms show that the new scheme can enhance the security significantly compared with typical LSB-based approaches as well as their edge adaptive ones, such as pixel-value-differencing-based approaches, while preserving higher visual quality of stego images at the same time.

Human gingiva-derived mesenchymal stem cells elicit polarization of m2 macrophages and enhance cutaneous wound healing.

Abstract: Increasing evidence has supported the important role of mesenchymal stem cells (MSCs) in wound healing, however, the underlying mechanism remains unclear. Recently, we have isolated a unique population of MSCs from human gingiva (GMSCs) with similar stem cell-like properties, immunosuppressive, and anti-inflammatory functions as human bone marrow-derived MSCs (BMSCs). We describe here the interplay between GMSCs and macrophages and the potential relevance in skin wound healing. When cocultured with GMSCs, macrophages acquired an anti-inflammatory M2 phenotype characterized by an increased expression of mannose receptor (MR; CD206) and secretory cytokines interleukin (IL)-10 and IL-6, a suppressed production of tumor necrosis factor (TNF)-α, and decreased ability to induce Th-17 cell expansion. In vivo, we demonstrated that systemically infused GMSCs could home to the wound site in a tight spatial interaction with host macrophages, promoted them toward M2 polarization, and significantly enhanced wound repair. Mechanistically, GMSC treatment mitigated local inflammation mediated by a suppressed infiltration of inflammatory cells and production of IL-6 and TNF-α, and an increased expression of IL-10. The GMSC-induced suppression of TNF-α secretion by macrophages appears to correlate with impaired activation of NFκB p50. These findings provide first evidence that GMSCs are capable to elicit M2 polarization of macrophages, which might contribute to a marked acceleration of wound healing.

Systematic comparison of constitutive promoters and the doxycycline-inducible promoter.

Abstract: Constitutive promoters are used routinely to drive ectopic gene expression. Here, we carried out a systematic comparison of eight commonly used constitutive promoters (SV40, CMV, UBC, EF1A, PGK and CAGG for mammalian systems, and COPIA and ACT5C for Drosophila systems). We also included in the comparison the TRE promoter, which can be activated by the rtTA transcriptional activator in a doxycycline-inducible manner. To make our findings representative, we conducted the comparison in a variety of cell types derived from several species. We found that these promoters vary considerably from one another in their strength. Most promoters have fairly consistent strengths across different cell types, but the CMV promoter can vary considerably from cell type to cell type. At maximal induction, the TRE promoter is comparable to a strong constitutive promoter. These results should facilitate more rational choices of promoters in ectopic gene expression studies.

Endogenous toll-like receptor ligands and their biological significance.

Abstract: Toll-like receptors (TLRs), a family of pattern recognition receptors, recognize and respond to conserved components of microbes and play a crucial role in both innate and adaptive immunity. In addition to binding exogenous ligands derived from pathogens, TLRs interact with endogenous molecules released from damaged tissues or dead cells and regulate many sterile inflammation processes. Putative endogenous TLR ligands include proteins and peptides, polysaccharides and proteoglycan, nucleic acids and phospholipids, which are cellular components, particularly extracellular matrix degradation products. Accumulating evidence demonstrates that endogenous ligand-mediated TLR signalling is involved in pathological conditions such as tissue injury, repair and regeneration; autoimmune diseases and tumorigenesis. The ability of TLRs to recognize endogenous stimulators appears to be essential to their function in regulating non-infectious inflammation. In this review, we summarize current knowledge of endogenous TLR ligands and discuss the biological significance of TLR signalling triggered by endogenous ligands in several sterile inflammation conditions.

I warn you because I like you: Voice behavior, employee identifications, and transformational leadership

Abstract: Voice behavior refers to the behavior that proactively challenges the status quo and makes constructive changes. Previous studies have explored the antecedents of employees' voice behavior, but to whom employees are likely to voice their thoughts has remained rarely examined. We propose that voice behavior is target-sensitive and that there are two types of voice behavior: speaking out (voice toward peers) and speaking up (voice toward the supervisor). Transformational leadership facilitates both speaking out and speaking up. However, it produces effects on employees via different types of employee identifications. Specifically, social identification predicts only speaking out, while personal identification predicts only speaking up. In contrast, affiliative extra-role behavior is less target-sensitive, and transformational leadership influences affiliative extra-role behavior via both social identification and personal identification. We examined our hypotheses by collecting both self-reported and coworker data from 191 Chinese employees in different organizations. Our hypotheses gained general support from the data. Implications for research and practice are discussed.

Roles of arabidopsis WRKY18, WRKY40 and WRKY60 transcription factors in plant responses to abscisic acid and abiotic stress.

Abstract: WRKY transcription factors are involved in plant responses to both biotic and abiotic stresses. Arabidopsis WRKY18, WRKY40, and WRKY60 transcription factors interact both physically and functionally in plant defense responses. However, their role in plant abiotic stress response has not been directly analyzed. We report that the three WRKYs are involved in plant responses to abscisic acid (ABA) and abiotic stress. Through analysis of single, double, and triple mutants and overexpression lines for the WRKY genes, we have shown that WRKY18 and WRKY60 have a positive effect on plant ABA sensitivity for inhibition of seed germination and root growth. The same two WRKY genes also enhance plant sensitivity to salt and osmotic stress. WRKY40, on the other hand, antagonizes WRKY18 and WRKY60 in the effect on plant sensitivity to ABA and abiotic stress in germination and growth assays. Both WRKY18 and WRKY40 are rapidly induced by ABA, while induction of WRKY60 by ABA is delayed. ABA-inducible expression of WRKY60 is almost completely abolished in the wrky18 and wrky40 mutants. WRKY18 and WRKY40 recognize a cluster of W-box sequences in the WRKY60 promoter and activate WRKY60 expression in protoplasts. Thus, WRKY60 might be a direct target gene of WRKY18 and WRKY40 in ABA signaling. Using a stable transgenic reporter/effector system, we have shown that both WRKY18 and WRKY60 act as weak transcriptional activators while WRKY40 is a transcriptional repressor in plant cells. We propose that the three related WRKY transcription factors form a highly interacting regulatory network that modulates gene expression in both plant defense and stress responses by acting as either transcription activator or repressor.

Interleukin-8 mediates resistance to antiangiogenic agent sunitinib in renal cell carcinoma.

Abstract: The broad spectrum kinase inhibitor sunitinib is a first-line therapy for advanced clear cell renal cell carcinoma (ccRCC), a deadly form of kidney cancer. Unfortunately, most patients develop sunitinib resistance and progressive disease after about 1 year of treatment. In this study, we evaluated the mechanisms of resistance to sunitinib to identify the potential tactics to overcome it. Xenograft models were generated that mimicked clinical resistance to sunitinib. Higher microvessel density was found in sunitinib-resistant tumors, indicating that an escape from antiangiogenesis occurred. Notably, escape coincided with increased secretion of interleukin-8 (IL-8) from tumors into the plasma, and coadministration of an IL-8 neutralizing antibody resensitized tumors to sunitinib treatment. In patients who were refractory to sunitinib treatment, IL-8 expression was elevated in ccRCC tumors, supporting the concept that IL-8 levels might predict clinical response to sunitinib. Our results reveal IL-8 as an important contributor to sunitinib resistance in ccRCC and a candidate therapeutic target to reverse acquired or intrinsic resistance to sunitinib in this malignancy.

Vandetanib plus docetaxel versus docetaxel as second-line treatment for patients with advanced non-small-cell lung cancer (ZODIAC): a double-blind, randomised, phase 3 trial.

Abstract: Summary Background Vandetanib is a once-daily oral inhibitor of vascular endothelial growth factor receptor (VEGFR), epidermal growth factor receptor (EGFR), and rearranged during transfection (RET) tyrosine kinases. In a randomised phase 2 study in patients with previously treated non-small-cell lung cancer (NSCLC), adding vandetanib 100 mg to docetaxel significantly improved progression-free survival (PFS) compared with docetaxel alone, including a longer PFS in women. These results supported investigation of the combination in this larger, definitive phase 3 trial (ZODIAC). Methods Between May, 2006, and April, 2008, patients with locally advanced or metastatic (stage IIIB–IV) NSCLC after progression following first-line chemotherapy were randomly assigned 1:1 through a third-party interactive voice system to receive vandetanib (100 mg/day) plus docetaxel (75 mg/m 2 intravenously every 21 days; maximum six cycles) or placebo plus docetaxel. The primary objective was comparison of PFS between the two groups in the intention-to-treat population. Women were a coprimary analysis population. This study has been completed and is registered with ClinicalTrials.gov, number NCT00312377. Findings 1391 patients received vandetanib plus docetaxel (n=694 [197 women]) or placebo plus docetaxel (n=697 [224 women]). Vandetanib plus docetaxel led to a significant improvement in PFS versus placebo plus docetaxel (hazard ratio [HR] 0·79, 97·58% CI 0·70–0·90; p vs 7/690 [1%]), neutropenia (199/689 [29%] vs 164/690 [24%]), leukopenia (99/689 [14%] vs 77/690 [11%]), and febrile neutropenia (61/689 [9%] vs 48/690 [7%]) were more common with vandetanib plus docetaxel than with placebo plus docetaxel. The most common serious adverse event was febrile neutropenia (46/689 [7%] in the vandetanib group vs 38/690 [6%] in the placebo group). Interpretation The addition of vandetanib to docetaxel provides a significant improvement in PFS in patients with advanced NSCLC after progression following first-line therapy. Funding AstraZeneca.

A Novel Set-Based Particle Swarm Optimization Method for Discrete Optimization Problems

Abstract: Particle swarm optimization (PSO) is predominately used to find solutions for continuous optimization problems. As the operators of PSO are originally designed in an n-dimensional continuous space, the advancement of using PSO to find solutions in a discrete space is at a slow pace. In this paper, a novel set-based PSO (S-PSO) method for the solutions of some combinatorial optimization problems (COPs) in discrete space is presented. The proposed S-PSO features the following characteristics. First, it is based on using a set-based representation scheme that enables S-PSO to characterize the discrete search space of COPs. Second, the candidate solution and velocity are defined as a crisp set, and a set with possibilities, respectively. All arithmetic operators in the velocity and position updating rules used in the original PSO are replaced by the operators and procedures defined on crisp sets, and sets with possibilities in S-PSO. The S-PSO method can thus follow a similar structure to the original PSO for searching in a discrete space. Based on the proposed S-PSO method, most of the existing PSO variants, such as the global version PSO, the local version PSO with different topologies, and the comprehensive learning PSO (CLPSO), can be extended to their corresponding discrete versions. These discrete PSO versions based on S-PSO are tested on two famous COPs: the traveling salesman problem and the multidimensional knapsack problem. Experimental results show that the discrete version of the CLPSO algorithm based on S-PSO is promising.

Do Bank Regulation, Supervision and Monitoring Enhance or Impede Bank Efficiency?

Abstract: The recent global financial crisis has spurred renewed interest in identifying those reforms in bank regulation that would work best to promote bank development, performance and stability. Building upon three recent world-wide surveys on bank regulation (Barth et al., 2004, 2006, and 2008), we attempt to contribute to this assessment by examining whether bank regulation, supervision and monitoring enhance or impede bank operating efficiency. Based on an unbalanced panel analysis of more than 4,050 banks observations in 72 countries over the time period 1999-2007, we find that tighter restrictions on bank activities are negatively associated with bank efficiency while greater capital regulation stringency is marginally and positively associated with bank efficiency. In addition, we find that a strengthening of official supervisory power is positively associated with bank efficiency only in countries with independent supervisory authorities. Moreover, independence coupled with a more experienced supervisory authority tends to enhance bank efficiency. Finally, market-based monitoring of banks in terms of more financial transparency is positively associated with bank efficiency.

A genome-wide association study of nasopharyngeal carcinoma identifies three new susceptibility loci.

Abstract: To identify genetic susceptibility loci for nasopharyngeal carcinoma (NPC), a genome-wide association study was performed using 464,328 autosomal SNPs in 1,583 NPC affected individuals (cases) and 1,894 controls of southern Chinese descent. The top 49 SNPs from the genome-wide association study were genotyped in 3,507 cases and 3,063 controls of southern Chinese descent from Guangdong and Guangxi. The seven supportive SNPs were further confirmed by transmission disequilibrium test analysis in 279 trios from Guangdong. We identified three new susceptibility loci, TNFRSF19 on 13q12 (rs9510787, Pcombined=1.53x10(-9), odds ratio (OR)=1.20), MDS1-EVI1 on 3q26 (rs6774494, Pcombined=1.34x10(-8), OR=0.84) and the CDKN2A-CDKN2B gene cluster on 9p21 (rs1412829, Pcombined=4.84x10(-7), OR=0.78). Furthermore, we confirmed the role of HLA by revealing independent associations at rs2860580 (Pcombined=4.88x10(-67), OR=0.58), rs2894207 (Pcombined=3.42x10(-33), OR=0.61) and rs28421666 (Pcombined=2.49x10(-18), OR=0.67). Our findings provide new insights into the pathogenesis of NPC by highlighting the involvement of pathways related to TNFRSF19 and MDS1-EVI1 in addition to HLA molecules.

Epstein-Barr virus-encoded EBNA1 inhibits the canonical NF-κB pathway in carcinoma cells by inhibiting IKK phosphorylation

Abstract: Background The Epstein-Barr virus (EBV)-encoded EBNA1 protein is expressed in all EBV-associated tumours, including undifferentiated nasopharyngeal carcinoma (NPC), where it is indispensable for viral replication, genome maintenance and viral gene expression. EBNA1's transcription factor-like functions also extend to influencing the expression of cellular genes involved in pathways commonly dysregulated during oncogenesis, including elevation of AP-1 activity in NPC cell lines resulting in enhancement of angiogenesis in vitro. In this study we sought to extend these observations by examining the role of EBNA1 upon another pathway commonly deregulated during carcinogenesis; namely NF-κB.

A new landscape index for quantifying urban expansion using multi-temporal remotely sensed data

Abstract: Landscape metrics or indices have been commonly used for quantifying landscape patterns. However, most of these indices are generally focused on simple analysis and description of the characterization of the geometric and spatial properties of categorical map patterns. These indices can hardly obtain the information about the spatio-temporal dynamic changes of landscape patterns, especially when multi-temporal remote sensing data are used. In this paper, a new landscape index, i.e., landscape expansion index (LEI), is proposed to solve such problems. In contrast with conventional landscape indices which are capable of reflecting the spatial characteristics for only one single time point, LEI and its variants can capture the information of the formation processes of a landscape pattern. This allows one to quantify the dynamic changes in two or more time points. These proposed indices have been applied to the measurement of the urban expansion of Dongguan in Guangdong province, China, for the period of 1988–2006. The analysis identifies three urban growth types, i.e., infilling, edge-expansion and outlying. A further analysis of different values of LEI in each period reveals a general temporal transition between phases of diffusion and coalescence in urban growth. This implies that the regularity in the spatiotemporal pattern of urban development in Dongguan, is consistent with the explanations according to urban development theories.

A translational study of circulating cell-free microRNA-1 in acute myocardial infarction.

Abstract: miRNAs (microRNAs) participate in many diseases including cardiovascular disease. In contrast with our original hypothesis, miRNAs exist in circulating blood and are relatively stable due to binding with other materials. The aim of the present translational study is to establish a method of determining the absolute amount of an miRNA in blood and to determine the potential applications of circulating cell-free miR-1 (microRNA-1) in AMI (acute myocardial infarction). The results revealed that miR-1 is the most abundant miRNA in the heart and is also a heart- and muscle-specific miRNA. In a cardiac cell necrosis model induced by Triton X-100 in vitro, we found that cardiac miR-1 can be released into the culture medium and is stable at least for 24 h. In a rat model of AMI induced by coronary ligation, we found that serum miR-1 is quickly increased after AMI with a peak at 6 h, in which an increase in miR-1 of over 200-fold was demonstrated. The miR-1 level returned to basal levels at 3 days after AMI. Moreover, the serum miR-1 level in rats with AMI had a strong positive correlation with myocardial infarct size. To verify further the relationship between myocardial size and miR-1 level, an IP (ischaemic preconditioning) model was used. The results showed that IP significantly reduced circulating miR-1 levels and myocardial infract size induced by I/R (ischaemia/reperfusion) injury. Finally, the levels of circulating cell-free miR-1 were significantly increased in patients with AMI and had a positive correlation with serum CK-MB (creatine kinase-MB) levels. In conclusion, the results suggest that serum miR-1 could be a novel sensitive diagnostic biomarker for AMI.

Telomere elongation in induced pluripotent stem cells from dyskeratosis congenita patients

Abstract: Patients with dyskeratosis congenita (DC), a disorder of telomere maintenance, suffer degeneration of multiple tissues. Patient-specific induced pluripotent stem (iPS) cells represent invaluable in vitro models for human degenerative disorders like DC. A cardinal feature of iPS cells is acquisition of indefinite self-renewal capacity, which is accompanied by induction of the telomerase reverse transcriptase gene (TERT). We investigated whether defects in telomerase function would limit derivation and maintenance of iPS cells from patients with DC. Here we show that reprogrammed DC cells overcome a critical limitation in telomerase RNA component (TERC) levels to restore telomere maintenance and self-renewal. We discovered that TERC upregulation is a feature of the pluripotent state, that several telomerase components are targeted by pluripotency-associated transcription factors, and that in autosomal dominant DC, transcriptional silencing accompanies a 3' deletion at the TERC locus. Our results demonstrate that reprogramming restores telomere elongation in DC cells despite genetic lesions affecting telomerase, and show that strategies to increase TERC expression may be therapeutically beneficial in DC patients.

Genome-wide association study identifies 1p36.22 as a new susceptibility locus for hepatocellular carcinoma in chronic hepatitis B virus carriers

Abstract: Gangqiao Zhou and colleagues report a genome-wide association study for hepatocellular carcinoma in chronic hepatitis B virus carriers, identifying a new susceptibility locus at chromosome 1p36.22.

Mir-30 reduction maintains self-renewal and inhibits apoptosis in breast tumor-initiating cells

Abstract: Accumulating evidence indicates that a sub-population of cancer cells with stem-like properties, termed tumor-initiating cells (T-ICs), exist in many different kinds of malignancies, which have a pivotal role in tumorigenesis, tumor progression, metastasis and post-treatment relapse. However, how the stem-like properties of T-ICs are regulated remains obscure. Our previous study showed that reduction of let-7 microRNA (miRNA) in breast tumor-initiating cells (BT-ICs) contributes to the maintenance of their self-renewal capacity and undifferentiated status. In this study we show the effect of mir-30 reduction on the stem-like features of BT-ICs. Similar to let-7, mir-30 is reduced in BT-ICs, and the protein level of Ubc9 (ubiquitin-conjugating enzyme 9) and ITGB3 (integrin beta3), the target genes of mir-30, is markedly upregulated. Enforced constitutive expression of mir-30 in BT-ICs inhibits their self-renewal capacity by reducing Ubc9, and induces apoptosis through silencing ITGB3. On the contrary, blocking the miRNA with a specific antisense oligonucleotide (ASO) in differentiated breast cancer cells revived their self-renewal capacity. Furthermore, ectopic expression of mir-30 in BT-IC xenografts reduces tumorigenesis and lung metastasis in nonobese diabetic/severe combined immunodeficient mice, whereas blocking mir-30 expression enhances tumorigenesis and metastasis. Together, our data suggest mir-30 as one of the important miRNAs in regulating the stem-like features of T-ICs.

Nestin is required for the proper self-renewal of neural stem cells.

Abstract: The intermediate filament protein, nestin, is a widely employed marker of multipotent neural stem cells (NSCs). Recent in vitro studies have implicated nestin in a number of cellular processes, but there is no data yet on its in vivo function. Here, we report the construction and functional characterization of Nestin knockout mice. We found that these mice show embryonic lethality, with neuroepithelium of the developing neural tube exhibiting significantly fewer NSCs and much higher levels of apoptosis. Consistent with this in vivo observation, NSC cultures derived from knockout embryos show dramatically reduced self-renewal ability that is associated with elevated apoptosis but no overt defects in cell proliferation or differentiation. Unexpectedly, nestin deficiency has no detectable effect on the integrity of the cytoskeleton. Furthermore, the knockout of Vimentin, which abolishes nestin's ability to polymerize into intermediate filaments in NSCs, does not lead to any apoptotic phenotype. These data demonstrate that nestin is important for the proper survival and self-renewal of NSCs, and that this function is surprisingly uncoupled from nestin's structural involvement in the cytoskeleton.

Apatinib (YN968D1) Reverses Multidrug Resistance by Inhibiting the Efflux Function of Multiple ATP-Binding Cassette Transporters

Abstract: Apatinib, a small-molecule multitargeted tyrosine kinase inhibitor, is in phase III clinical trial for the treatment of patients with non–small-cell lung cancer and gastric cancer in China. In this study, we determined the effect of apatinib on the interaction of specific antineoplastic compounds with P-glycoprotein (ABCB1), multidrug resistance protein 1 (MRP1, ABCC1), and breast cancer resistance protein (BCRP, ABCG2). Our results showed that apatinib significantly enhanced the cytotoxicity of ABCB1 or ABCG2 substrate drugs in KBv200, MCF-7/adr, and HEK293/ABCB1 cells overexpressing ABCB1 and in S1-M1-80, MCF-7/FLV1000, and HEK293/ABCG2-R2 cells overexpressing ABCG2 (wild-type). In contrast, apatinib did not alter the cytotoxicity of specific substrates in the parental cells and cells overexpressing ABCC1. Apatinib significantly increased the intracellular accumulation of rhodamine 123 and doxorubicin in the multidrug resistance (MDR) cells. Furthermore, apatinib significantly inhibited the photoaffinity labeling of both ABCB1 and ABCG2 with [125I]iodoarylazidoprazosin in a concentration-dependent manner. The ATPase activity of both ABCB1 and ABCG2 was significantly increased by apatinib. However, apatinib, at a concentration that produced a reversal of MDR, did not significantly alter the ABCB1 or ABCG2 protein or mRNA expression levels or the phosphorylation of AKT and extracellular signal–regulated kinase 1/2 (ERK1/2). Importantly, apatinib significantly enhanced the effect of paclitaxel against the ABCB1-resistant KBv200 cancer cell xenografts in nude mice. In conclusion, apatinib reverses ABCB1- and ABCG2-mediated MDR by inhibiting their transport function, but not by blocking the AKT or ERK1/2 pathway or downregulating ABCB1 or ABCG2 expression. Apatinib may be useful in circumventing MDR to other conventional antineoplastic drugs. Cancer Res; 70(20); 7981–91. ©2010 AACR.

Antineoplastic Mechanisms of Niclosamide in Acute Myelogenous Leukemia Stem Cells: Inactivation of the NF-κB Pathway and Generation of Reactive Oxygen Species

Abstract: NF-kappaB may be a potential therapeutic target for acute myelogenous leukemia (AML) because NF-kappaB activation is found in primitive human AML blast cells. In this report, we initially discovered that the potent antineoplastic effect of niclosamide, a Food and Drug Administration-approved antihelminthic agent, was through inhibition of the NF-kappaB pathway in AML cells. Niclosamide inhibited the transcription and DNA binding of NF-kappaB. It blocked tumor necrosis factor-induced IkappaBalpha phosphorylation, translocation of p65, and expression of NF-kappaB-regulated genes. Niclosamide inhibited the steps TAK1-->IkappaB kinase (IKK) and IKK-->IkappaBalpha. Niclosamide also increased the levels of reactive oxygen species (ROS) in AML cells. Quenching ROS by the glutathione precursor N-acetylcysteine attenuated niclosamide-induced apoptosis. Our results together suggest that niclosamide inhibited the NF-kappaB pathway and increased ROS levels to induce apoptosis in AML cells. On translational study of the efficacy of niclosamide against AML, niclosamide killed progenitor/stem cells from AML patients but spared those from normal bone marrow. Niclosamide was synergistic with the frontline chemotherapeutic agents cytarabine, etoposide, and daunorubicin. It potently inhibited the growth of AML cells in vitro and in nude mice. Our results support further investigation of niclosamide in clinical trials of AML patients.