Epidermal growth factor receptor (EGFR) mutation is strongly associated with the therapeutic effect of tyrosine kinase inhibitors (TKIs) in patients with non-small-cell lung cancer (NSCLC). Nevertheless, tumor tissue that needed for mutation analysis is frequently unavailable. Body fluid was considered to be a feasible substitute for the analysis, but arising problems in clinical practice such as relatively lower mutation rate and poor clinical correlation are not yet fully resolved.
In this study, 50 patients (32 pleural fluids and 18 plasmas) with TKIs therapy experience and with direct sequencing results were selected from 220 patients for further analysis. The EGFR mutation status was re-evaluated by Amplification Refractory Mutation System (ARMS), and the clinical outcomes of TKIs were analyzed retrospectively.
As compared with direct sequencing, 16 positive and 23 negative patients were confirmed by ARMS, and the other 11 former negative patients (6 pleural fluids and 5 plasmas) were redefined as positive, with a fairly well clinical outcome (7 PR, 3 SD, and 1 PD). The objective response rate (ORR) of positive patients was significant, 81.3% (direct sequencing) and 72.7% (ARMS) for pleural fluids, and 80% (ARMS) for plasma. Notably, even reclassified by ARMS, the ORR for negative patients was still relatively high, 60% for pleural fluids and 46.2% for plasma.
When using body fluids for EGFR mutation analysis, positive result is consistently a good indicator for TKIs therapy, and the predictive effect was no less than that of tumor tissue, no matter what method was employed. However, even reclassified by ARMS, the correlation between negative results and clinical outcome of TKIs was still unsatisfied. The results indicated that false negative mutation still existed, which may be settled by using method with sensitivity to single DNA molecule or by optimizing the extraction procedure with RNA or CTC to ensure adequate amount of tumor-derived nucleic acid for the test.
Body Fluids; EGFR Mutation; Direct Sequencing; ARMS; TKIs; NSCLC
Pulmonary hypertension (PH) contributes to the mortality of
patients with lung and heart diseases. However, the underlying
mechanism has not been completely elucidated. Accumulating
evidence suggests that inflammatory response may be involved in
the pathogenesis of PH. Macrophage migration inhibitory factor
(MIF) is a critical upstream inflammatory mediator which promotes
a broad range of pathophysiological processes. The aim of the
study was to investigate the role of MIF in the pulmonary vascular
remodeling of hypoxia-induced PH. We found that MIF mRNA and
protein expression was increased in the lung tissues from hypoxic
pulmonary hypertensive rats. Intensive immunoreactivity for MIF
was observed in smooth muscle cells of large pulmonary arteries
(PAs), endothelial cells of small PAs, and inflammatory cells of
hypoxic lungs. MIF participated in the hypoxia-induced PASMCs
proliferation, and it could directly stimulate proliferation of
these cells. MIF-induced enhanced growth of PASMCs was attenuated
by MEK and JNK inhibitor. Besides, MIF antagonist ISO-1 suppressed
the ERK1/2 and JNK phosphorylation induced by MIF. In conclusion,
the current finding suggested that MIF may act on the
proliferation of PASMCs through the activation of the ERK1/2 and
JNK pathways, which contributes to hypoxic pulmonary hypertension.
Infectious hematopoietic necrosis virus (IHNV) is an important fish pathogen that infects both wild and cultured salmonids. As a species of the genus Novirhabdovirus, IHNV is a valuable model system for exploring the host entry mechanisms of rhabdoviruses. In this study, quantum dots (QDs) were used as fluorescent labels for sensitive, long-term tracking of IHNV entry. Using live-cell fluorescence microscopy, we found that IHNV is internalized through clathrin-coated pits after the virus binds to host cell membranes. Pretreatment of host cells with chlorpromazine, a drug that blocks clathrin-mediated endocytosis, and clathrin light chain (LCa) depletion using RNA interference both resulted in a marked reduction in viral entry. We also visualized transport of the virus via the cytoskeleton (i.e., actin filaments and microtubules) in real time. Actin polymerization is involved in the transport of endocytic vesicles into the cytosol, whereas microtubules are required for the trafficking of clathrin-coated vesicles to early endosomes, late endosomes, and lysosomes. Disrupting the host cell cytoskeleton with cytochalasin D or nocodazole significantly impaired IHNV infectivity. Furthermore, infection was significantly affected by pretreating the host cells with bafilomycin A1, a compound that inhibits the acidification of endosomes and lysosomes. Strong colocalizations of IHNV with endosomes indicated that the virus is internalized into these membrane-bound compartments. This is the first report in which QD labeling is used to visualize the dynamic interactions between viruses and endocytic structures; the results presented demonstrate that IHNV enters host cells via clathrin-mediated endocytic, cytoskeleton-dependent, and low-pH-dependent pathways.
Hypoxia is a common microenvironment in solid tumors and is correlated with tumor progression by regulating cancer cell survival. Recent studies suggest that activation of double-stranded RNA-dependent protein kinase-like endoplasmic reticulum-related kinase (PERK) and phosphorylation of α subunit of eIF2 (eIF2α) confer cell adaptation to hypoxic stress. However, eIF2α is still phosphorylated at a lowered level in PERK knockout cells under hypoxic conditions. The mechanism for eIF2α kinase(s) (eIF2AK)-increased cell survival is not clear. In this report, we provide evidence that another eIF2AK, the amino acid starvation-dependent general control of amino acid biosynthesis kinase (GCN2), is also involved in hypoxia-induced eIF2α phosphorylation. We demonstrate that both GCN2 and PERK mediate the cell adaptation to hypoxic stress. High levels of eIF2α phosphorylation lead to G1 arrest and protect cells from hypoxia-induced apoptosis. Reduced phosphorylation of eIF2α by knocking out either PERK or GCN2 suppresses hypoxia-induced G1 arrest and promotes apoptosis in accompany with activation of p53 signal cascade. However, totally abolishing phosphorylation of eIF2α inhibits G1 arrest without promoting apoptosis. On the basis of our results, we propose that the levels of eIF2α phosphorylation serve as a “switch” in regulation of G1 arrest or apoptosis under hypoxic conditions.
The conserved Translin-TRAX complexes, also known as C3PO, have been implicated in many biological processes, but how they function remains unclear. Recently, C3PO was shown to be an endoribonuclease that promotes RNA interference in animal cells. Here we show that C3PO does not play a significant role in RNAi in the filamentous fungus Neurospora crassa. Instead, the Neurospora C3PO functions as a ribonuclease that removes the 5′ pre-tRNA fragments after the processing of pre-tRNAs by RNase P. In addition, the translin and trax mutants have elevated levels of tRNA and protein translation and are more resistant to a cell-death inducing agent. Finally, we showed that C3PO is also involved in tRNA processing in mouse embryonic fibroblast cells. Together, this study identified the endogenous RNA substrates of C3PO and provides a potential explanation for its roles in seemingly diverse biological processes.
The incidence of Mycobacterium marinum infection has been increasing. First-line antituberculous drugs and other common antibiotics are effective for most cutaneous M. marinum infections; however, treatment failure still occurs in some rare cases. We report a case of a 70-year-old man with refractory cutaneous infection caused by M. marinum. Reasons for delayed diagnosis and related factors of the refractory infection are also discussed.
Samples of lesional skin were inoculated on Löwenstein–Jensen medium for acid-fast bacilli. Species of mycobacterium were identified by polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) analysis. We then carried out genotyping by using mycobacterial interspersed repetitive units and sequencing of heat shock protein 65 (hsp65) and 16S rDNA genes.
Tissue cultures for acid-fast bacilli were positive. PCR-RFLP analysis and sequencing of hsp65 and 16S rDNA genes confirmed the isolated organisms to be M. marinum. Systemic therapy with rifampicin, clarithromycin, and amikacin empirically over 6 months led to complete resolution of skin lesions leaving only some residual scars.
Key diagnostic elements for M. marinum infections include a high index of suspicion raised by chronic lesions, poor response to conventional treatments, and a history of fish-related exposure. Strong clinical suggestion of M. marinum infection warrants initial empirical treatment. The duration of therapy is usually several months or even longer, especially for elderly patients. Amikacin can be considered in multidrug therapy for treatment of some refractory M. marinum infections.
amikacin; clarithromycin; skin infection; Mycobacterium marinum; nontuberculous mycobacteria
We aim to predict radiological observations using computationally-derived imaging features extracted from computed tomography (CT) images. We created a dataset of 79 CT images containing liver lesions identified and annotated by a radiologist using a controlled vocabulary of 76 semantic terms. Computationally-derived features were extracted describing intensity, texture, shape, and edge sharpness. Traditional logistic regression was compared to L1-regularized logistic regression (LASSO) in order to predict the radiological observations using computational features. The approach was evaluated by leave one out cross-validation. Informative radiological observations such as lesion enhancement, hypervascular attenuation, and homogeneous retention were predicted well by computational features. By exploiting relationships between computational and semantic features, this approach could lead to more accurate and efficient radiology reporting.
Nutrition-related health issues have emerged as a major threat to public health since the rebirth of the economy in China starting in the 1980s. To meet this challenge, the Chinese Academy of Sciences established the Institute for Nutritional Sciences (INS) at Shanghai, China ∼8 y ago. The mission of the INS is to apply modern technologies and concepts in nutritional research to understand the molecular mechanism and provide means of intervention in the combat against nutrition-related diseases, including type 2 diabetes, metabolic syndrome, obesity, cardiovascular diseases, and many types of cancers. Through diligent and orchestrated efforts by INS scientists, graduate students, and research staff in the past few years, the INS has become the leading institution in China in the areas of basic nutritional research and metabolic regulation. Scientists at the INS have made important progress in many areas, including the characterization of genetic and nutritional properties of the Chinese population, metabolic control associated with nutrient sensing, molecular mechanisms underlying glucose and lipid metabolism, regulation of metabolism by adipokines and inflammatory pathways, disease intervention using functional foods or extracts of Chinese herbs, and many biological studies related to carcinogenesis. The INS will continue its efforts in understanding the optimal nutritional needs for Chinese people and the molecular causes associated with metabolic diseases, thus paving the way for effective and individualized intervention in the future. This review highlights the major research endeavors undertaken by INS scientists in recent years.
Over the last two decades, multiple classifier system (MCS) or classifier ensemble has shown great potential to improve the accuracy and reliability of remote sensing image classification. Although there are lots of literatures covering the MCS approaches, there is a lack of a comprehensive literature review which presents an overall architecture of the basic principles and trends behind the design of remote sensing classifier ensemble. Therefore, in order to give a reference point for MCS approaches, this paper attempts to explicitly review the remote sensing implementations of MCS and proposes some modified approaches. The effectiveness of existing and improved algorithms are analyzed and evaluated by multi-source remotely sensed images, including high spatial resolution image (QuickBird), hyperspectral image (OMISII) and multi-spectral image (Landsat ETM+). Experimental results demonstrate that MCS can effectively improve the accuracy and stability of remote sensing image classification, and diversity measures play an active role for the combination of multiple classifiers. Furthermore, this survey provides a roadmap to guide future research, algorithm enhancement and facilitate knowledge accumulation of MCS in remote sensing community.
multiple classifier system; classifier ensemble; remote sensing; classification
Acute pulmonary embolism (APE) remains a diagnostic challenge due to a variable clinical presentation and the lack of a reliable screening tool. MicroRNAs (miRNAs) regulate gene expression in a wide range of pathophysiologic processes. Circulating miRNAs are emerging biomarkers in heart failure, type 2 diabetes and other disease states; however, using plasma miRNAs as biomarkers for the diagnosis of APE is still unknown.
Thirty-two APE patients, 32 healthy controls, and 22 non-APE patients (reported dyspnea, chest pain, or cough) were enrolled in this study. The TaqMan miRNA microarray was used to identify dysregulated miRNAs in the plasma of APE patients. The TaqMan-based miRNA quantitative real-time reverse transcription polymerase chain reactions were used to validate the dysregulated miRNAs. The receiver-operator characteristic (ROC) curve analysis was conducted to evaluate the diagnostic accuracy of the miRNA identified as the candidate biomarker.
Plasma miRNA-134 (miR-134) level was significantly higher in the APE patients than in the healthy controls or non-APE patients. The ROC curve showed that plasma miR-134 was a specific diagnostic predictor of APE with an area under the curve of 0.833 (95% confidence interval, 0.737 to 0.929; P < 0.001).
Our findings indicated that plasma miR-134 could be an important biomarker for the diagnosis of APE. Because of this finding, large-scale investigations are urgently needed to pave the way from basic research to clinical utilization.
During fasting, mammals maintain glucose homeostasis by stimulating hepatic gluconeogenesis1. Elevations in circulating glucagon (GLU) and epinephrine trigger the cAMP mediated phosphorylation of Creb and dephosphorylation of the Creb coactivator Crtc22. Although the underlying mechanism is unclear, hepatic gluconeogenesis is also regulated by the circadian clock, which coordinates glucose metabolism with changes in the external environment3–6. Here we show that Creb activity during fasting is modulated by Cryptochromes (Cry1 and Cry2), core components of the clock that are rhythmically expressed in the liver. Cry was elevated during the night/day transition, when it reduced fasting gluconeogenic gene expression by blocking GLU-mediated increases in intracellular cAMP concentrations and in the PKA-mediated phosphorylation of Creb. In biochemical reconstitution studies, we found that Cry inhibited accumulation of cAMP in response to G protein coupled receptor (GPCR) activation but not to forskolin, a direct activator of adenyl cyclase. Cry appeared to modulate GPCR activity directly through interaction with Gsα . As hepatic over-expression of Cry lowered blood glucose concentrations and improved insulin sensitivity in insulin resistant db/db mice, our results suggest that compounds which enhance Cry activity may provide therapeutic benefit to individuals with type II diabetes.
In an effort to find new pharmacological modalities to overcome resistance to ATP-site inhibitors of Bcr-Abl, we recently reported the discovery of GNF-2, a selective allosteric Bcr-Abl inhibitor. Here, using solution NMR, X-ray crystallography, mutagenesis and hydrogen exchange mass spectrometry we demonstrate that GNF-2 binds to the myristate binding site of Abl, leading to changes in the structural dynamics of the ATP-binding site. GNF-5, an analog of GNF-2 having improved pharmacokinetic properties, when utilized in combination with the ATP-competitive inhibitors imatinib or nilotinib, suppressed the emergence of resistance mutations in vitro, displayed additive inhibitory activity in biochemical and cellular assays against T315I Bcr-Abl and displayed in vivo efficacy against the recalcitrant T315I Bcr-Abl mutant in a murine bone-marrow transplantation model. These results demonstrate that therapeutically relevant inhibition of Bcr-Abl activity can be achieved using inhibitors that bind to the myristate binding site and that combining allosteric and ATP-competitive inhibitors can overcome resistance to either agent alone.
Pulmonary vascular structure remodeling (PVSR) is a hallmark of pulmonary hypertension. P27kip1, one of critical cyclin-dependent kinase inhibitors, has been shown to mediate anti-proliferation effects on various vascular cells. Beta-estradiol (β-E2) has numerous biological protective effects including attenuation of hypoxic pulmonary hypertension (HPH). In the present study, we employed β-E2 to investigate the roles of p27kip1 and its closely-related kinase (Skp-2) in the progression of PVSR and HPH.
Sprague-Dawley rats treated with or without β-E2 were challenged by intermittent chronic hypoxia exposure for 4 weeks to establish hypoxic pulmonary hypertension models, which resemble moderate severity of hypoxia-induced PH in humans. Subsequently, hemodynamic and pulmonary pathomorphology data were gathered. Additionally, pulmonary artery smooth muscle cells (PASMCs) were cultured to determine the anti-proliferation effect of β-E2 under hypoxia exposure. Western blotting or reverse transcriptional polymerase chain reaction (RT-PCR) were adopted to test p27kip1, Skp-2 and Akt-P changes in rat lung tissue and cultured PASMCs.
Chronic hypoxia significantly increased right ventricular systolic pressures (RVSP), weight of right ventricle/left ventricle plus septum (RV/LV+S) ratio, medial width of pulmonary arterioles, accompanied with decreased expression of p27kip1 in rats. Whereas, β-E2 treatment repressed the elevation of RVSP, RV/LV+S, attenuated the PVSR of pulmonary arterioles induced by chronic hypoxia, and stabilized the expression of p27kip1. Study also showed that β-E2 application suppressed the proliferation of PASMCs and elevated the expression of p27kip1 under hypoxia exposure. In addition, experiments both in vivo and in vitro consistently indicated an escalation of Skp-2 and phosphorylated Akt under hypoxia condition. Besides, all these changes were alleviated in the presence of β-E2.
Our results suggest that β-E2 can effectively attenuate PVSR and HPH. The underlying mechanism may partially be through the increased p27kip1 by inhibiting Skp-2 through Akt signal pathway. Therefore, targeting up-regulation of p27kip1 or down-regulation of Skp-2 might provide new strategies for treatment of HPH.
Periodontitis is one of the most widespread infectious diseases in humans. It is the main cause of tooth loss and associated with a number of systemic diseases. Until now, there is no appropriate method for functional periodontal tissue regeneration. Here, we establish a novel approach of using allogeneic periodontal ligament stem cells (PDLSCs) sheet to curing periodontitis in a miniature pig periodontitis model. Significant periodontal tissue regeneration was achieved in both the autologous and the allogeneic PDLSCs transplantation group at 12 weeks post-PDLSCs transplantation. Based on clinical assessments, computed tomography (CT) scanning, and histological examination, there was no marked difference between the autologous and allogeneic PDLSCs transplantation groups. In addition, lack of immunological rejections in the animals that received the allogeneic PDLSCs transplantation was observed. Interestingly, we found that human PDLSCs fail to express human leukocyte antigen (HLA)-II DR and costimulatory molecules. PDLSCs were not able to elicit T-cell proliferation and inhibit T-cell proliferation when stimulated with mismatched major histocompatibility complex molecules. Furthermore, we found that prostaglandin E2 (PGE2) plays a crucial role in PDLSCs-mediated immunomodulation and periodontal tissue regeneration in vitro and in vivo. Our study demonstrated that PDLSCs possess low immunogenicity and marked immunosuppression via PGE2-induced T-cell anergy. We developed a standard technological procedure of using allogeneic PDLSCs to cure periodontitis in swine. Stem Cells 2010;28:1829–1838
Periodontal ligament stem cells; Immunogenicity; Immunosuppression; Tissue engineering
In this report, the peptide linker connecting scFv VH and VL domains were genetically modified to contain different amino acids (i.e. cysteine (scFv-cys) or histidines ( scFv-his)) to enable the scFv to adsorb or self-assemble onto the gold nanoparticles (NPs). The scFv-cys stabilized gold NPs were used to develop a highly sensitive colorimetric immunosensor. The scFv-cys stabilized gold NPs were characterized by UV-vis spectra, transmission electron microscope (TEM) and FT-IR. After adding the antigen rabbit IgG, the solution of scFv-cys stabilized gold NPs shows obvious visible color change from deep red to light purple due to the aggregation of the gold nanoparticles. Based on the colorimetric aggregation of scFv-cys stabilized gold NPs, the immunosensor exhibits high sensitivity with detection limit of 1.7 nM and good specificity. The good properties of the colorimetric aggregation immunosensor would be attributed to the small size of scFv and the covalent link between the scFv and gold NPs that improve the better orientation and enhance the probe density. With the advantages of speed, simplicity and specificity, the colorimetric immunoassay based on the functionalized scFv stabilized gold NPs represents a promising approach for protein analysis and clinical diagnostics.
gold nanoparticle; scFv; colorimetric immunoassay
Early stage diabetic nephropathy is characterized by elevated glomerular filtration. Recent studies have identified high-glucose induced p38 MAPK (p38) over-activation in mesangial cells. Mesangial hypocontractility is the major underlying mechanism, however, no ameliorating agents are currently available. We investigated the protective effects of emodin on high-glucose induced mesangial cell hypocontractility. Mesangial cells were cultured under normal (5.6 mM) and high glucose (30 mM) conditions. Emodin was administrated at doses of 50 mg/l and 100 mg/l. Angiotension II stimulated cell surface reductions were measured to evaluate cell contractility. p38 activity was detected using Western blotting. To further explore the possible mechanism of emodin, expression of the peroxisome proliferator-activated receptor γ (PPARγ) was measured and its specific inhibitor, gw9662, was administrated. Our results showed: (1) high-glucose resulted in a 280% increase in p38 activity associated with significant impairment of mesangial contractility; (2) emodin treatment dose-dependently inhibited high-glucose induced p38 over-activation (a 40% decrease for 50 mg/l emodin and a 73% decrease for 100 mg/l emodin), and mesangial hypocontractility was ameriolated by emodin; (3) both the PPARγ mRNA and protein levels were elevated after emodin treatment; (4) inhibition of PPARγ using gw9662 effectively blocked the ameliorating effects of emodin on high-glucose induced p38 over-activation and mesangial hypocontractility. Emodin effectively ameliorated p38 over-activation and hypocontractility in high-glucose induced mesangial cells, possibly via activation of PPARγ.
diabetic nephropathies; emodin; hyperglycemia; mesangial cells; p38 mitogen-activated protein kinases
AIM: To investigate the role of insulin-like growth factor binding protein-7 (IGFBP-7) in the activation and transdifferentiation of hepatic stellate cells (HSC) in vitro.
METHODS: Rat HSC-T6 cells were cultured in separate dishes and treated with various concentration of transforming growth factor (TGF)-β1, IGFBP-7 or anti-IGFBP-7 antibody for 24 h. The supernatant or a cytoplasm suspension was obtained from cultured HSC, followed by transfer of cells to form cell-coated dishes. Immunocytochemistry and Western blotting were used to analyze the expression of IGFBP-7 induced by TGF-β1 and the level of fibronectin, collagen I and α-smooth muscle actin (SMA). The pro-apoptotic effect of anti-IGFBP-7 antibody was determined by flow cytometry.
RESULTS: Immunocytochemistry and Western blotting revealed that the expression of IGFBP-7 in TGF-β1 treated HSC was significantly up-regulated compared to that in the control group. In addition, fibronectin, collagen I and α-SMA also showed enhanced expression in accordance with the transdifferentiation process in a dose-dependent manner to some extent. Moreover, flow cytometry suggested that anti-IGFBP-7 antibody induced apoptosis of activated HSC, which is responsible for the development of liver fibrosis, and may represent a novel pathway and target for therapeutic intervention.
CONCLUSION: IGFBP-7 showed increased expression in activated HSC and played an important role in the activation and transdifferentiation process of HSC. Anti-IGFBP-7 antibody may ameliorate liver fibrogenesis.
Insulin-like growth factor-binding protein-7; Smooth muscle actin; Fibronectins; Collagen type I; Hepatic stellate cells
Some clinical case reports have shown that immature permanent teeth with periradicular periodontitis or abscess can undergo apexogenesis after conservative endodontic treatment. A call for a paradigm shift and new protocol for the clinical management of these cases has been brought to attention. Concomitantly, a new population of mesenchymal stem cells residing in the apical papilla of permanent immature teeth recently has been discovered and was termed stem cells from the apical papilla (SCAP). These stem cells appear to be the source of odontoblasts that are responsible for the formation of root dentin. Conservation of these stem cells when treating immature teeth may allow continuous formation of the root to completion. This article reviews current findings on the isolation and characterization of these stem cells. The potential role of these stem cells in the following respects will be discussed: (1) their contribution in continued root maturation in endodontically treated immature teeth with periradicular periodontitis or abscess and (2) their potential utilization for pulp/dentin regeneration and bioroot engineering.
Apexogenesis; apical papilla; bioroot engineering; dental pulp stem cells; immature teeth; periodontal ligament stem cells; pulp regeneration; stem cells from human exfoliated deciduous teeth; stem cells from the apical papilla
Recent data have redefined the concept of inflammation as a critical component of tumor progression. However, there has been little development on cases where inflammation on or near a wound and a tumor exist simultaneously. Therefore, this pilot study aims to observe the impact of a wound on a tumor, to build a new mouse tumor model with a manufactured surgical wound representing acute inflammation, and to evaluate the relationship between acute inflammation or wound healing and the process of tumor growth. We focus on the two phases that are present when acute inflammation influences tumor. In the early phase, inhibitory effects are present. The process that produces these effects is the functional reaction of IFN-γ secretions from a wound inflammation. In the latter phase, the inhibited tumor is made resistant to IFN-γ through the release of TGF-β to balance the inflammatory factor effect on the tumor cells. A pair of cytokines IFN-γ/TGF-β established a new balance to protect the tumor from the interference effect of the inflammation. The tumor was made resistant to IFN-γ through the release of TGF-β to balance the inflammatory effect on the tumor cells. This balance mechanism that occurred in the tumor cells increased proliferation and invasion. In vitro and in vivo experiments have confirmed a new view of clinical surgery that will provide more detailed information on the evaluation of tumors after surgery. This study also provides a better understanding of the relationship between tumor and inflammation, as well as tumor cell attacks on inflammatory factors.
When recognized by the RNA interference (RNAi) pathway, double-stranded RNA (dsRNA) produced in eukaryotic cells results in posttranscriptional gene silencing. In addition, dsRNA can trigger the interferon response as part of the immune response in vertebrates. In this study, we show that dsRNA, but not short interfering RNA (siRNA), induces the expression of qde-2 (an Argonaute gene) and dcl-2 (a Dicer gene), two central components of the RNAi pathway in the filamentous fungus Neurospora crassa. The induction of QDE-2 by dsRNA is required for normal gene silencing, indicating that this is a regulatory mechanism that allows the optimal function of the RNAi pathway. In addition, we demonstrate that Dicer proteins (DCLs) regulate QDE-2 posttranscriptionally, suggesting a role for DCLs or siRNA in QDE-2 accumulation. Finally, a genome-wide search revealed that additional RNAi components and homologs of antiviral and interferon-stimulated genes are also dsRNA-activated genes in Neurospora. Together, our results suggest that the activation of the RNAi components is part of a broad ancient host defense response against viral and transposon infections.
Mesenchymal stem cell-mediated tissue regeneration is a promising approach for regenerative medicine for a wide range of applications. Here we report a new population of stem cells isolated from the root apical papilla of human teeth (SCAP, stem cells from apical papilla). Using a minipig model, we transplanted both human SCAP and periodontal ligament stem cells (PDLSCs) to generate a root/periodontal complex capable of supporting a porcelain crown, resulting in normal tooth function. This work integrates a stem cell-mediated tissue regeneration strategy, engineered materials for structure, and current dental crown technologies. This hybridized tissue engineering approach led to recovery of tooth strength and appearance.
The mechanistic target of rapamycin (mTOR) is a serine/threonine kinase whose activity contributes to leukemia proliferation and survival. Compounds targeting the mTOR active site inhibit rapamycin-resistant functions and have enhanced anti-cancer activity in mouse models. MLN0128 (formerly known as INK128) is a novel, orally active mTOR kinase inhibitor currently in clinical development. Here we evaluated MLN0128 in preclinical models of B-cell acute lymphoblastic leukemia (B-ALL). MLN0128 suppressed proliferation of B-ALL cell lines in vitro and reduced colony formation by primary human leukemia cells from adult and pediatric B-ALL patients. MLN0128 also boosted the efficacy of dasatinib in Philadelphia Chromosome-positive (Ph+) specimens. In a syngeneic mouse model of lymphoid BCR-ABL+ disease, daily oral dosing of MLN0128 rapidly cleared leukemic outgrowth. In primary xenografts of Ph+ B-ALL specimens, MLN0128 significantly enhanced the efficacy of dasatinib. In non-Ph B-ALL xenografts, single agent MLN0128 had a cytostatic effect that was most pronounced in mice with low disease burden. In all in vivo models, MLN0128 was well tolerated and did not suppress endogenous bone marrow proliferation. These findings support the rationale for clinical testing of MLN0128 in both adult and pediatric B-ALL and provide insight towards optimizing therapeutic efficacy of mTOR kinase inhibitors.
kinase inhibitor; mTOR; leukemia
We previously showed that tanshinone IIA ameliorated the hypoxia-induced pulmonary hypertension (HPH) partially by attenuating pulmonary artery remodeling. The hypoxia-induced proliferation of pulmonary artery smooth muscle cells (PASMCs) is one of the major causes for pulmonary arterial remodeling, therefore the present study was performed to explore the effects and underlying mechanism of tanshinone IIA on the hypoxia-induced PASMCs proliferation. PASMCs were isolated from male Sprague-Dawley rats and cultured in normoxic (21%) or hypoxic (3%) condition. Cell proliferation was measured with 3 - (4, 5 - dimethylthiazal - 2 - yl) - 2, 5 - diphenyltetrazoliumbromide assay and cell counting. Cell cycle was measured with flow cytometry. The expression of of p27, Skp-2 and the phosphorylation of Akt were measured using western blot and/or RT-PCR respectively. The results showed that tanshinone IIA significantly inhibited the hypoxia-induced PASMCs proliferation in a concentration-dependent manner and arrested the cells in G1/G0-phase. Tanshinone IIA reversed the hypoxia-induced reduction of p27 protein, a cyclin-dependent kinase inhibitor, in PASMCs by slowing down its degradation. Knockdown of p27 with specific siRNA abolished the anti-proliferation of tanshinone IIA. Moreover, tanshinone IIA inhibited the hypoxia-induced increase of S-phase kinase-associated protein 2 (Skp2) and the phosphorylation of Akt, both of which are involved in the degradation of p27 protein. In vivo tanshinone IIA significantly upregulated the hypoxia-induced p27 protein reduction and downregulated the hypoxia-induced Skp2 increase in pulmonary arteries in HPH rats. Therefore, we propose that the inhibition of tanshinone IIA on hypoxia-induce PASMCs proliferation may be due to arresting the cells in G1/G0-phase by slowing down the hypoxia-induced degradation of p27 via Akt/Skp2-associated pathway. The novel information partially explained the anti-remodeling property of tanshinone IIA on pulmonary artery in HPH.