eEF-2 kinase is a critical regulator of Warburg effect through controlling PP2A-A synthesis

Cancer cells predominantly metabolize glucose by glycolysis to produce energy in order to meet their metabolic requirement, a phenomenon known as Warburg effect. Although Warburg effect is considered a peculiarity critical for survival and proliferation of cancer cells, the regulatory mechanisms behind this phenomenon remain incompletely understood. We report here that eukaryotic elongation factor-2 kinase (eEF-2K), a negative regulator of protein synthesis, has a critical role in promoting glycolysis in cancer cells. We showed that deficiency in eEF-2K significantly reduced the uptake of glucose and decreased the productions of lactate and adenosine triphosphate in tumor cells and in the Ras-transformed mouse embryonic fibroblasts. We further demonstrated that the promotive effect of eEF-2K on glycolysis resulted from the kinase-mediated restriction of synthesis of the protein phosphatase 2A-A (PP2A-A), a key factor that facilitates the ubiquitin-proteasomal degradation of c-Myc protein, as knockdown of eEF-2K expression led to a significant increase in PP2A-A protein synthesis and remarkable downregulation of c-Myc and pyruvate kinase M2 isoform, the key glycolytic enzyme transcriptionally activated by c-Myc. In addition, depletion of eEF-2K reduced the ability of the transformed cells to proliferate and enhanced the sensitivity of tumor cells to chemotherapy both in vitro and in vivo. These results, which uncover a role of the eEF-2K-mediated control of PP2A-A in tumor cell glycolysis, provide new insights into the regulation of the Warburg effect.

Efficient oxygen electroreduction over ordered mesoporous Co–N-doped carbon derived from cobalt porphyrin

High-performance self-supported Co–N-doped carbon electrocatalyst for ORR with comparable activity to Pt/C in both acidic and alkaline media was prepared.

Lentivirus-mediated RNA interference of myostatin gene affects MyoD and Myf5 gene expression in duck embryonic myoblasts

The aim of this study was to construct lentivirus-mediated short hairpin RNA (shRNA) vectors targeting the duck MSTN gene and investigate whether these vectors can affect the development of duck primary cultured embryonic myoblasts. MSTN mRNA levels in the myoblasts were detected using quantitative real-time polymerase chain reaction (PCR), cell proliferation was assessed by MTT assays and cell differentiation was assayed by photography. MSTN mRNA levels in PLL3.7-MSTN-shRNA1, PLL3.7-MSTN-shRNA2 and PLL3.7-MSTN-shRNA3 lentivirus-mediated shRNA groups were reduced by 61.6%, 76.9% and 79.1%, respectively, compared to control cells. Down-regulation of MSTN in duck embryonic myoblasts stimulated cell proliferation and inhibited differentiation, accompanied by a greater than twofold down-regulation of MyoD expression and up-regulation of Myf5 expression. These results revealed that silencing of MSTN changes the development of duck embryonic myoblasts by regulating the expression level of MyoD and Myf5 genes.

Evaluation of improved γ-aminobutyric acid production in yogurt using Lactobacillus plantarum NDC75017

Most γ-aminobutyric acid (GABA)-producing microorganisms are lactic acid bacteria (LAB), but the yield of GABA is limited in most of these GABA-producing strains. In this study, the production of GABA was carried out by using Lactobacillus plantarum NDC75017, a strain screened from traditional fermented dairy products in China. Concentrations of substrate (l-monosodium glutamate, L-MSG) and coenzyme (pyridoxal-5-phosphate, PLP) of glutamate decarboxylase (GAD) and culture temperature were investigated to evaluate their effects on GABA yield of Lb. plantarum NDC75017. The results indicated that GABA production was related to GAD activity and biomass of Lb. plantarum NDC75017. Response surface methodology was used to optimize conditions of GABA production. The optimal factors for GABA production were L-MSG at 80 mM, PLP at 18 μM, and a culture temperature of 36 °C. Under these conditions, production of GABA was maximized at 314.56 mg/100 g. Addition of Lb. plantarum NDC75017 to a commercial starter culture led to higher GABA production in fermented yogurt. Flavor and texture of the prepared yogurt and the control yogurt did not differ significantly. Thus, Lb. plantarum NDC75017 has good potential for manufacture of GABA-enriched fermented milk products.

Combination of adenoviruses expressing melanoma differentiation-associated gene-7 and chemotherapeutic agents produces enhanced cytotoxicity on esophageal carcinoma

We examined the combinatory antitumor effects of adenoviruses expressing human mda-7/IL-24 gene (Ad-mda-7) and chemotherapeutic agents on nine kinds of human esophageal carcinoma cells. All the carcinoma cells expressed the melanoma differentiation-associated gene-7/interleukin-24 (MDA-7/IL-24) receptor complexes, IL-20R2 and either IL-20R1 or IL-22R1, and were susceptible to Ad-mda-7, whereas fibroblasts were positive only for IL-20R2 gene and resistant to Ad-mda-7-mediated cytotoxicity. Sensitivity of these esophageal carcinoma cells to Ad-mda-7 was however lower than that to Ad expressing the wild-type p53 gene. We thereby investigated a possible combination of Ad-mda-7 and anticancer agents and found that Ad-mda-7 with 5-fluorouracil (5-FU), cisplatin, mitomycin C or etoposide produced greater cytotoxic effects than those by Ad-mda-7 or the agent alone. Half-maximal inhibitory concentration values of the agents in respective cells were decreased by the combination with Ad-mda-7. Cell cycle analyses showed that Ad-mda-7 and 5-FU increased G2/M-phase and S-phase populations, respectively, and the combination augmented sub-G1 populations. Ad-mda-7-treated cells showed cleavages of caspase-8, -9 and -3 and poly (ADP-ribose) polymerase, but the cleavage levels were not different from those of the combination-treated cells. Ad-mda-7 treatments upregulated Akt phosphorylation but suppressed IκB-α levels, whereas 5-FU treatments induced phosphorylation of p53 and extracellular signal-regulated protein kinases 1 and 2. Molecular changes caused by the combination were similar to those by Ad-mda-7 treatments, but the Ad-mda-7-mediated upregulation of Akt phosphorylation decreased with the combination. These data collectively suggest that Ad-mda-7 induced apoptosis despite Akt activation and that the combinatory antitumor effects with 5-FU were produced partly by downregulating the Ad-mda-7-induced Akt activation.

Imbalance of different types of CD4(+) forkhead box protein 3 (FoxP3)(+) T cells in patients with new-onset systemic lupus erythematosus

The aim of this study was to examine the numbers of CD4(+) CD25(-) forkhead box protein 3 (FoxP3)(+) , CD4(+) CD25(+) FoxP3(+) and CD4(+) CXCR5(+) FoxP3(+) T cells in patients with new-onset systemic lupus erythematosus (SLE). The numbers of CD4(+) CD25(-) FoxP3(+) , CD4(+) CD25(+) FoxP3(+) and CD4(+) CXCR5(+) FoxP3(+) T cells and the concentrations of serum interleukin (IL)-10 in 23 patients and 20 healthy controls (HC) were measured. The potential correlations between CD4(+) FoxP3(+) T cells, serum IL-10 and clinical measures in SLE patients were analysed. In comparison with that in the HC, significantly reduced numbers of CD4(+) CD25(+) FoxP3(+) and CD4(+) CXCR5(+) FoxP3(+) T cells, but increased numbers of CD4(+) CD25(-) FoxP3(+) T cells, were detected, accompanied by significantly lower levels of serum IL-10 in the patients. Stratification analysis indicated the numbers of CD4(+) CD25(+) FoxP3(+) and CD4(+) CXCR5(+) FoxP3(+) T cells and serum IL-10 levels in the patients with seropositive anti-dsDNA were significantly less than that in those with seronegative anti-dsDNA. Treatment with the anti-SLE therapy, particularly with prednisone, leflunomide and methotrexate, significantly improved the imbalance of these types of FoxP3(+) T cells and increased the concentrations of serum IL-10 in the drug-responding patients. The numbers of CD4(+) CD25(+) FoxP3(+) T cells were correlated negatively with the values of SLE disease activity index (SLEDAI), whereas the numbers of CD4(+) CD25(-) FoxP3(+) T cells were correlated positively with the values of SLEDAI, erythrocyte sedimentation rate (ESR) and serum C3. In addition, the concentrations of serum IL-10 were correlated positively with the numbers of CD4(+) CD25(+) FoxP3(+) T cells, but negatively with the values of SLEDAI, serum C3, CRP and ESR in these patients. Our data indicate that the imbalance of different types of FoxP3(+) CD4(+) T cells may contribute to the development of SLE in Chinese patients.

High frequencies of activated B cells and T follicular helper cells are correlated with disease activity in patients with new-onset rheumatoid arthritis

This study aimed to examine the frequency of different subsets of circulating B and T follicular helper (Tfh) cells in patients with new-onset rheumatoid arthritis (RA) and following standard therapies. Twenty-five RA patients and 15 healthy controls (HC) were recruited for characterizing the frequency of CD27⁺, immunoglobulin (Ig)D⁺, CD86⁺, CD95⁺, Toll-like receptor (TLR)-9⁺ B cells and inducible T cell co-stimulator (ICOS) and programmed death 1 (PD-1)-positive Tfh cells and the level of serum interleukin (IL)-21. The potential correlation between the frequency of different subsets of B and Tfh cells and the values of clinical measures in RA patients was analysed. In comparison with HC, significantly higher percentages of circulating IgD⁺ CD27⁻ CD19⁺ naive B, CD86⁺ CD19⁺ and CD95⁺ CD19⁺ activated B, CD3⁺ CD4⁺ CXCR5⁺, CD3⁺ CD4⁺ CXCR5⁺ ICOS⁺, CD3⁺ CD4⁺ CXCR5⁺ PD-1⁺ and CD3⁺ CD4⁺ CXCR5⁺ ICOS⁺ PD-1⁺ Tfh cells but lower IgD⁺ CD27⁺ CD19⁺ preswitch memory B cells were detected, accompanied by significantly higher levels of serum IL-21 in the RA patients. Furthermore, the percentages of CD95⁺ B cells were correlated positively with the frequency of PD-1⁺ Tfh cells, but negatively with ICOS⁺ Tfh cells. The percentages of CD86⁺ B cells and ICOS⁺ Tfh cells were correlated positively with the values of disease activity score 28 (DAS28). Following the drug therapies for 1 month, the percentages of CD86⁺ B and PD-1⁺ Tfh cells were reduced significantly in the drug-responding patients. Our data suggest that activated B and Tfh cells may contribute to the pathogenesis of RA and the frequency of activated B and Tfh cells may be used as biomarkers for evaluating the therapeutic responses of individual patients with RA.

Piperlongumine induces autophagy by targeting p38 signaling

Piperlongumine (PL), a natural product isolated from the plant species Piper longum L., can selectively induce apoptotic cell death in cancer cells by targeting the stress response to reactive oxygen species (ROS). Here we show that PL induces cell death in the presence of benzyloxycarbonylvalyl-alanyl-aspartic acid (O-methyl)-fluoro-methylketone (zVAD-fmk), a pan-apoptotic inhibitor, and in the presence of necrostatin-1, a necrotic inhibitor. Instead PL-induced cell death can be suppressed by 3-methyladenine, an autophagy inhibitor, and substantially attenuated in cells lacking the autophagy-related 5 (Atg5) gene. We further show that PL enhances autophagy activity without blocking autophagy flux. Application of N-acetyl-cysteine, an antioxidant, markedly reduces PL-induced autophagy and cell death, suggesting an essential role for intracellular ROS in PL-induced autophagy. Furthermore, PL stimulates the activation of p38 protein kinase through ROS-induced stress response and p38 signaling is necessary for the action of PL as SB203580, a p38 inhibitor, or dominant-negative p38 can effectively reduce PL-mediated autophagy. Thus, we have characterized a new mechanism for PL-induced cell death through the ROS-p38 pathway. Our findings support the therapeutic potential of PL by triggering autophagic cell death.

Interaction of Sirt3 with OGG1 contributes to repair of mitochondrial DNA and protects from apoptotic cell death under oxidative stress

Sirtuin 3 (Sirt3), a major mitochondrial NAD(+)-dependent deacetylase, targets various mitochondrial proteins for lysine deacetylation and regulates important cellular functions such as energy metabolism, aging, and stress response. In this study, we identified the human 8-oxoguanine-DNA glycosylase 1 (OGG1), a DNA repair enzyme that excises 7,8-dihydro-8-oxoguanine (8-oxoG) from damaged genome, as a new target protein for Sirt3. We found that Sirt3 physically associated with OGG1 and deacetylated this DNA glycosylase and that deacetylation by Sirt3 prevented the degradation of the OGG1 protein and controlled its incision activity. We further showed that regulation of the acetylation and turnover of OGG1 by Sirt3 played a critical role in repairing mitochondrial DNA (mtDNA) damage, protecting mitochondrial integrity, and preventing apoptotic cell death under oxidative stress. We observed that following ionizing radiation, human tumor cells with silencing of Sirt3 expression exhibited deteriorated oxidative damage of mtDNA, as measured by the accumulation of 8-oxoG and 4977 common deletion, and showed more severe mitochondrial dysfunction and underwent greater apoptosis in comparison with the cells without silencing of Sirt3 expression. The results reported here not only reveal a new function and mechanism for Sirt3 in defending the mitochondrial genome against oxidative damage and protecting from the genotoxic stress-induced apoptotic cell death but also provide evidence supporting a new mtDNA repair pathway.

IL-12 and IL-10 production are differentially regulated by phosphatidylinositol 3-kinase in mast cells

The cellular mechanisms that directly regulate the production of pro- and anti-inflammatory cytokines after lipopolysaccharide (LPS) stimulation in mast cells are currently unresolved. The aim of this study was to clarify the role of phosphatidylinositol 3-kinase (PI3K) in the production of IL-12 and IL-10 in mouse bone marrow-derived mast cells (BMMCs), stimulated with Escherichia coli-derived LPS. LPS activates the PI3K signalling pathway; analysis of cytokine production following LPS stimulation of BMMCs revealed that inhibition of the PI3K pathway differentially regulated IL-10 and IL-12 syntheses. IL-12 production was enhanced, whereas IL-10 levels were suppressed. Inhibition of LPS-mediated activation of the PI3K pathway resulted in a pronounced reduction of NF-κB activity that was dependent on IκBα phosphorylation. These findings demonstrate a regulatory function for PI3K in modulating IL-10 and IL-12 production in mast cells and provide insight into how engagement of the PI3K pathway affects the induction of key immunoregulatory cytokines that control both qualitative and quantitative aspects of early inflammation.

Recent advances in antiangiogenic agents with VEGFR as target

Angiogenesis is required for invasive tumor growth and metastasis and constitutes an important point in the control of cancer progression. Its inhibition may be a valuable approach to cancer therapy. Antiangiogenic agents are designed to attack the tumor vasculature and cut off the tumor's supply of nutrients. Systemic blockade of angiogenesis has been recently approved for the treatment of several types of human cancers. Antiangiogenic therapy presents various advantages as compared to conventional treatment. Vascular endothelial growth factor (VEGF) is considered to be one of the most important regulators of angiogenesis and a key target in anticancer treatment. VEGF binding to its receptor (VEGFR) leads to cell proliferation and new vascular formation by tyrosine kinase (TK) pathway. VEGF/VEGFR pathway is becoming attractive target for anticancer drug design. It is believed to be important in the control of angiogenesis. Antiangiogenic therapy based on inhibition of VEGFR was reported to be powerful clinical strategies. In this review, the authors describe the existing literature regarding VEGFR inhibitors in the last few years. We attempt to cover all essential publications on the medicinal chemistry in terms of chemical structure, pharmacological profile and structure-activity relationships.

Sulphoraphane inhibited the expressions of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 through MyD88-dependent toll-like receptor-4 pathway in cultured endothelial cells

BACKGROUND AND AIMS

Chronic inflammation plays pivotal roles in both cancer and cardiovascular diseases. A large body of evidence suggests that high intake of cruciferous vegetables is closely related with low risk of these disorders. However, the underlying mechanisms of protection are not fully understood. The aim of this study is to test the protective effects of an isothiocyanate sulphoraphane on inflammatory injury and related regulation pathways in cultured endothelial cells.

METHODS AND RESULTS

The expressions of adhesion molecules were determined by TaqMan real-time polymerase chain reaction (PCR) and Western blot analysis. Nuclear factor-kappa B (NF-кB) translocation was detected by immunofluorescent hybridisation. Other proteins were measured by Western blot analysis. The results demonstrated that sulphoraphane significantly suppresses the expression of intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 stimulated by lipopolysaccharide (LPS) both at the transcriptional and translational levels. In addition, sulphoraphane inhibited the translocation of NF-кB into the nucleus. Sulphoraphane decreased the phosphorylation of extra-cellular signal-regulated kinase (ERK), Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK), while further blockade and activation using individually specific agents confirm that p38 MAPK and JNK are mainly involved. Interestingly, sulphoraphane down-regulated Toll-like receptor (TLR)-4, a receptor of LPS located on the membrane. In addition, MyD88, an effector downstream TLR-4 signal pathway was subsequently attenuated.

CONCLUSION

Taken all together, adhesion molecules are confirmed to be the novel targets of sulphoraphane in preventing inflammatory insult to endothelial cells. Sulphoraphane suppressed TLR-4 followed by MyD88 and downstream factors such as p38 MAPK and JNK, ultimately blocking NF-кB translocation and the subsequent expression of adhesion molecules. These data suggested a novel inflammatory pathway mediated by sulphoraphane.

Acoustic interrogation and optical visualization of ultrasound contrast agents within microcapsules

The effectiveness of localized drug delivery as a treatment for breast cancer requires sufficiently high therapeutic dose, as well as an ability to image the drug for proper spatial targeting. To balance treatment potential and imaging capabilities, we have begun to design a novel drug reservoir using microcapsules that are large in size (> 30 µm) but functionalized with microbubbles or ultrasound contrast agents (UCAs). We term these carriers as 'Acoustically Sensitive Microcapsules' (ASMs). In previous work, we have demonstrated preparation of ASM carriers and their structural changes under therapeutic ultrasound by imaging static changes. In this paper, we describe a combined optical-acoustic setup coupled with a microfluidic device to trap these carriers for imaging and sonication. Using the setup, continuous wave ultrasound (180 kPa, 2.25 MHz, 3 s) produced an average displacement of 3.5 µm in UCAs near the ASM boundary, and exhibited displacement as high as 90 µm near the center of the microcapsule. Longer exposure time and higher acoustic pressure increased UCA displacement within an ASM. These two parameters can be carefully optimized in the future to cause these UCAs to travel to the membrane boundary to help in the drug elution process.

Developments of combretastatin A-4 derivatives as anticancer agents

Tubulin protein is one of several members of a small family of globular proteins. It offers a potential target for anticancer drug design and development. Combretastatin A-4 (CA-4) is a potent anticancer and antiangiogenesis natural substance isolated from Combretum caffrum. Modifications on the CA-4 structure have led to a great number of novel CA-4 derivatives as potent tubulin inhibitors and high cytotoxic anticancer agents is becoming an interesting field, leading to a breakthrough in the treatment of cancer. In this review, the recent developments of novel CA-4 derivatives via the modifications on the A- and B-ring and the double bond as anticancer agents are discussed.

A multinational phase II study of liposome irinotecan (PEP02) for patients with gemcitabine-refractory metastatic pancreatic cancer

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Background: PEP02 is a novel nanoparticle liposome formulation of irinotecan (CPT-11) that has improved pharmacokinetics and tumor biodistribution of both CPT-11 and its active metabolite-SN38 compared to the free form drug. PEP02 has showed encouraging safety and efficacy in various tumor types, including significant antitumor activity in a human pancreatic cancer L3.6pl orthotopic nude mouse xenograft model. In previous phase I studies, PEP02 either alone or in combination with 5-FU/LV demonstrated prolonged disease control in 5 of 7 (71%) patients (pts) with gemcitabine (GEM)-refractory advanced pancreatic cancer (PC). This phase II study aims to evaluate PEP02 monotherapy as 2nd-line treatment in pts with metastatic, GEM-refractory PC.

Methods: Pts were eligible if they had metastatic pancreatic adenocarcinoma, KPS ≥ 70, and progressed following one line of GEM-based therapy. Treatment consisted of PEP02 120 mg/m2 administered as a 90-minute infusion every 3 weeks. A Simon's 2-stage design was used with 16 pts in the first stage and 39 pts in total; primary objective was 3-month survival rate (OS3-month).

Results: Between March 2009 and August 2010, 37 pts were enrolled at 3 centers in the U.S. and Taiwan. Characteristics for the first 31 evaluable pts: 13 M/18 F; age 39-82 yrs; 19 Asian/12 Caucasian, KPS 100/90/80/70: 5/14/4/8. Mean number of treatment cycles is 5 (range, 1-22). Disease control rate (minor response + stable disease >2 cycles) is 52%. 8 of 24 pts (33%) with elevated baseline CA19-9 have had >50% biomarker decline. To date, 23/31 pts (74%) have survived > 3 months, with 4 pts still alive after 1 year. Reasons for study discontinuation: 74% progressive disease, 9% drug-related toxicity, 17% other. Preliminary safety data is available for the first stage. Most common G3/4 adverse events included: fatigue (31%), neutropenia (25%), nausea/vomiting (19%), and diarrhea (13%).

Conclusions: This study has already met its primary endpoint (predicted OS3-month >65%). PEP02 appears to have both activity and tolerable side effects for pts with metastatic, GEM-refractory PC, and represents a promising option for this pt population with few standard options.

[Table: see text]