SIRT6 protects against hepatic ischemia/reperfusion injury by inhibiting apoptosis and autophagy related cell death

Silent information regulator 6 (SIRT6), a class III histone deacetylase, has been revealed to participate in multiple metabolic processes in the liver, and it plays important roles in protecting against ischemia/reperfusion (I/R) injury in multiple organs. In this study, we explored whether SIRT6 is protective against hepatic I/R injury and elucidated the underlying mechanisms. The expression of SIRT6 was significantly decreased during reperfusion compared with the control group. SIRT6-LKO mice exhibited significantly aggravated oxidative stress, mitochondrial dysfunction, inflammatory responses, mitogen-activated protein kinase (MAPK) signaling activation, and apoptosis and autophagy related hepatocyte death compared with control mice. In vitro studies in SIRT6-KO hepatocytes exhibited similar results. In contrast, SIRT6 upregulation alleviated liver damage during hepatic I/R injury. Our study demonstrated for the first time that SIRT6 upregulation effectively protects against hepatic I/R injury. The underlying mechanisms involve the maintenance of oxidative homeostasis and mitochondrial function, which subsequently inhibit the inflammatory responses and MAPK signaling, and finally attenuate apoptosis and autophagy related hepatocyte death. These results suggest that the activation of SIRT6 exerts multifaceted protective effects during hepatic I/R injury, which can provide a novel therapeutic target for hepatic I/R injury.

Targeting Gas6/TAM in cancer cells and tumor microenvironment

Growth arrest-specific 6, also known as Gas6, is a human gene encoding the Gas6 protein, which was originally found to be upregulated in growth-arrested fibroblasts. Gas6 is a member of the vitamin K-dependent family of proteins expressed in many human tissues and regulates several biological processes in cells, including proliferation, survival and migration, by binding to its receptors Tyro3, Axl and Mer (TAM). In recent years, the roles of Gas6/TAM signalling in cancer cells and the tumour microenvironment have been studied, and some progress has made in targeted therapy, providing new potential directions for future investigations of cancer treatment. In this review, we introduce the Gas6 and TAM receptors and describe their involvement in different cancers and discuss the roles of Gas6 in cancer cells, the tumour microenvironment and metastasis. Finally, we introduce recent studies on Gas6/TAM targeting in cancer therapy, which will assist in the experimental design of future analyses and increase the potential use of Gas6 as a therapeutic target for cancer.

Tailor-Making Fluorescent Hyaluronic Acid Microgels via Combining Microfluidics and Photoclick Chemistry for Sustained and Localized Delivery of Herceptin in Tumors

Antibody therapeutics, though representing a most used biomedicine, suffers from poor in vivo stability, rapid degradation, and frequent injections. Here, we report that fluorescent hyaluronic acid microgels (HMGs) tailor-made by combining microfluidics and "tetrazole-alkene" photoclick chemistry enable sustained and localized delivery of Herceptin in ovarian tumors. HMGs were obtained with a defined size (25-50 μm), narrow size distribution, high stability, and strong green fluorescence. Notably, HMGs exhibited a remarkably high loading of proteins such as Herceptin and IgG with a loading efficiency exceeding 90% at a theoretical protein-loading content of 30 wt %. In vitro protein release experiments revealed a sustained and hyaluronidase (HAase)-dependent release of Herceptin from HMGs, in which 80.6% of Herceptin was released at 1 U/mL HAase in 10 days. The released Herceptin maintained its secondary structure and antitumor activity. In vivo imaging results demonstrated obviously better tumoral retention for Cy5-labeled Herceptin-loaded HMGs following subcutaneous (sc) injection than for the free-protein counterpart. Interestingly, sc injection of the Herceptin-loaded HMGs into SKOV-3 human ovarian tumor-bearing nude mice at a dose of 30 mg Herceptin equiv/kg induced nearly complete tumor suppression, which was significantly more effective than the sc or systemic injection of free Herceptin. These tailor-made fluorescent HMGs appeared as a robust injectable platform for sustained and localized delivery of therapeutic proteins.

Clinical and pathological significance of N-Myc downstream-regulated gene 2 (NDRG2) in diverse human cancers

Human N-Myc downstream-regulated gene 2 (NDRG2), located at chromosome 14q11.2, has been reported to be down-regulated and associated with the progression and prognosis of diverse cancers. Collectively, previous studies suggest that NDRG2 functions as a candidate tumor-suppressor gene; thus, up-regulation of NDRG2 protein might act as a promising therapeutic strategy for malignant tumors. The aim of this review was to comprehensively present the clinical and pathological significance of NDRG2 in human cancers.

Dynamic kinetic resolution of biaryl atropisomers by chiral dialkylaminopyridine catalysts

Dynamic kinetic resolutions of atropisomers using chiral DMAPs with fluxional chirality.

Molecular Mechanisms of Antipsychotic Drug-Induced Diabetes

Antipsychotic drugs (APDs) are widely prescribed to control various mental disorders. As mental disorders are chronic diseases, these drugs are often used over a life-time. However, APDs can cause serious glucometabolic side-effects including type 2 diabetes and hyperglycaemic emergency, leading to medication non-compliance. At present, there is no effective approach to overcome these side-effects. Understanding the mechanisms for APD-induced diabetes should be helpful in prevention and treatment of these side-effects of APDs and thus improve the clinical outcomes of APDs. In this review, the potential mechanisms for APD-induced diabetes are summarized so that novel approaches can be considered to relieve APD-induced diabetes. APD-induced diabetes could be mediated by multiple mechanisms: (1) APDs can inhibit the insulin signaling pathway in the target cells such as muscle cells, hepatocytes and adipocytes to cause insulin resistance; (2) APD-induced obesity can result in high levels of free fatty acids (FFA) and inflammation, which can also cause insulin resistance. (3) APDs can cause direct damage to β-cells, leading to dysfunction and apoptosis of β-cells. A recent theory considers that both β-cell damage and insulin resistance are necessary factors for the development of diabetes. In high-fat diet-induced diabetes, the compensatory ability of β-cells is gradually damaged, while APDs cause direct β-cell damage, accounting for the severe form of APD-induced diabetes. Based on these mechanisms, effective prevention of APD-induced diabetes may need an integrated approach to combat various effects of APDs on multiple pathways.

Upregulation of UBE2Q1 via gene copy number gain in hepatocellular carcinoma promotes cancer progression through β-catenin-EGFR-PI3K-Akt-mTOR signaling pathway

Hepatocellular carcinoma (HCC) is the most common type of liver cancer and represents a highly malignant tumor with a poor prognosis. Therapeutic modalities for HCC are limited and generally ineffective. UBE2Q1 is a putative E2 ubiquitin conjugating enzyme, and has been shown to be overexpressed in various types of cancers including HCC. How UBE2Q1 contributes to hepatocarcinogenesis remains unknown. Here, we show that UBE2Q1 is up-regulated in HCC cell lines and in a subset of human HCC tissues. Up-regulation of UBE2Q1 in primary HCC tumors was significantly correlated with shorter overall survival and disease-free survival. Mechanistically, we showed that the frequent up-regulation of UBE2Q1 in HCCs was attributed to the recurrent UBE2Q1 gene copy gain at chromosome 1q21. Functionally, we showed that knockdown of UBE2Q1 reduced HCC cell proliferation, promoted apoptosis via induction of GADD45α, and suppressed orthotopic tumorigenicity both in vitro and in vivo. Inactivation of UBE2Q1 also impeded HCC cell migration and invasion in vitro through regulating EMT process, and suppressed HCC metastasis in vivo. Interestingly, our data revealed a role of UBE2Q1 in the regulation of β-catenin-EGFR-PI3K-Akt-mTOR signaling pathway. Our findings indicate that UBE2Q1 is a candidate oncogene involved in HCC development and progression and therefore a potential therapeutic target in applicable HCC patients.

Copper-Catalyzed Enantioselective Cyclopropanation of Internal Olefins with Diazomalonates

The first enantioselective copper catalyzed cyclopropanation of internal olefins with diazomalonates is reported. This process provides a new method for the synthesis of chiral 1,1-cyclopropane diesters. With a chiral bi-side arm bisoxazoline-copper(I) complex, the reaction performed well over a series of substrates, giving the desired products in good yields (up to 95%) and excellent enantioselectivities (90-95% ee).

Time-dependent effects of olanzapine treatment on the expression of histidine decarboxylase, H1 and H3 receptor in the rat brain: The roles in olanzapine-induced obesity

Antipsychotic treatment, particularly olanzapine and clozapine, induces severe obesity. The Histamine H1 receptor is considered to be an important contributor to olanzapine-induced obesity, however how olanzapine modulates the histaminergic system is not sufficiently understood. This study examined the effect of olanzapine on key molecules of the histaminergic system, including histidine decarboxylase (HDC), H1 receptor (H1R) and H3 receptor (H3R), in the brain at different stages of olanzapine-induced obesity. During short-term treatment (8-day), olanzapine increased hypothalamic HDC mRNA expression and H1R binding in the arcuate nucleus (Arc) and ventromedial hypothalamus (VMH), without changing H3R binding density. HDC mRNA and Arc H1R binding were positively correlated with increased food intake, feeding efficiency and weight gain. When the treatment was extended to 16 and 36 days, H1R binding was increased not only in the hypothalamic Arc and VMH but also in the brainstem dorsal vagal complex (DVC). The H1R bindings in the Arc, VMH and DVC were positively correlated with weight gain induced by olanzapine treatment. However, the expression of HDC and H3R mRNA was not increased. These results suggest that olanzapine time-dependently modulates histamine neurotransmission, which suggested the different neuronal mechanisms underlying different stages of weight gain development. Treatment targeting the H1R may be effective for both short- and long-term olanzapine-induced weight gain.

Targeted inhibition of human hematological cancers in vivo by doxorubicin encapsulated in smart lipoic acid-crosslinked hyaluronic acid nanoparticles

The chemotherapy of hematological cancers is challenged by its poor selectivity that leads to low therapeutic efficacy and pronounced adverse effects. Here, we report that doxorubicin encapsulated in lipoic acid-crosslinked hyaluronic acid nanoparticles (LACHA-DOX) mediate highly efficacious and targeted inhibition of human hematological cancers including LP-1 human multiple myeloma (MM) and AML-2 human acute myeloid leukemia xenografted in nude mice. LACHA-DOX had a size of ca. 183 nm and a DOX loading content of ca. 12.0 wt.%. MTT and flow cytometry assays showed that LACHA-DOX possessed a high targetability and antitumor activity toward CD44 receptor overexpressing LP-1 human MM cells and AML-2 human acute myeloid leukemia cells. The in vivo and ex vivo images revealed that LACHA-DOX achieved a significantly enhanced accumulation in LP-1 and AML-2 tumor xenografts. Notably, LACHA-DOX effectively suppressed LP-1 as well as AML-2 tumor growth and drastically increased mice survival rate as compared to control groups receiving free DOX or PBS. Histological analyses exhibited that LACHA-DOX caused little damage to the major organs like liver and heart. This study provides a proof-of-concept that lipoic acid-crosslinked hyaluronic acid nanoparticulate drugs may offer a more safe and effective treatment modality for CD44 positive hematological malignancies.

αvβ3 integrin-targeted micellar mertansine prodrug effectively inhibits triple-negative breast cancer in vivo

Antibody-mertansine (DM1) conjugates (AMCs) are among the very few active targeting therapeutics that are approved or clinically investigated for treating various cancers including metastatic breast cancer. However, none of the AMCs are effective for the treatment of triple-negative breast cancers (TNBCs). Here, we show that cRGD-decorated, redox-activatable micellar mertansine prodrug (cRGD-MMP) can effectively target and deliver DM1 to α_vβ₃ integrin overexpressing MDA-MB-231 TNBC xenografts in nude mice, resulting in potent tumor growth inhibition. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays showed that cRGD-MMP had obvious targetability to MDA-MB-231 cells with a low half-maximal inhibitory concentration (IC₅₀) of 0.18 μM, which was close to that of free DM1 and 2.2-fold lower than that of micellar mertansine prodrug (MMP; nontargeting control). The confocal microscopy studies demonstrated that cRGD-MMP mediated a clearly more efficient cellular uptake and intracellular release of doxorubicin (used as a fluorescent anticancer drug model) in MDA-MB-231 cells. Notably, cRGD-MMP loaded with 1,1′-dioctadecyltetramethyl indotricarbocyanine iodide (DiR; a hydrophobic near-infrared dye) was shown to quickly accumulate in the MDA-MB-231 tumor with strong DiR fluorescence from 2 to 24 h post injection. MMP loaded with DiR could also accumulate in the tumor, although significantly less than cRGD-MMP. The biodistribution studies revealed a high DM1 accumulation of 8.1%ID/g in the tumor for cRGD-MMP at 12 h post injection. The therapeutic results demonstrated that cRGD-MMP effectively suppressed MDA-MB-231 tumor growth at 1.6 mg DM1 equiv./kg without causing noticeable side effects, as shown by little body weight loss and histological analysis. This MMP has appeared as a promising platform for potent treatment of TNBCs.

Silica nanowire assemblies as three-dimensional, optically transparent platforms for constructing highly active SERS substrates

Three-dimensional surface-enhanced Raman scattering (SERS) substrates are prepared via the in situ deposition of silver nanoparticles (AgNPs) on silica nanowire (SiO₂ NW) assemblies, either in a free-standing membrane structure or as an optically transparent film supported on Scotch tape. The negatively charged surface of the SiO₂ NW favors Ag⁺ ion enrichment around itself, with the ions forming densely deposited AgNPs on the NW after reducing agents are added to the solution. A SERS substrate with high sensitivity is achieved owing to abundant "hot spots" generated by the inter-AgNP gaps in the 3D geometry of the NW networks. The AgNP-deposited SiO₂ NW membrane has a SERS enhancement factor of 2.9 × 10⁸ and a detection limit of 10^-9 M towards 4-mercaptopyridine probing and 10^-8 M towards dithiocarbamate pesticide (i.e., thiram) probing. Moreover, the AgNP-deposited, Scotch tape-supported SiO₂ NW film achieves non-invasive, direct detection of real-world surfaces due to its high sensitivity, high flexibility and optically transparent properties.

cRGD/TAT Dual-Ligand Reversibly Cross-Linked Micelles Loaded with Docetaxel Penetrate Deeply into Tumor Tissue and Show High Antitumor Efficacy in Vivo

The application of cell-penetrating peptides like TAT for in vivo targeted delivery is limited because the penetration behavior is not cell-specific. Herein, we designed cRGD and TAT comodified cross-linkable micelles (cRGD/TAT CMs), in which the TAT peptide was shielded by relatively long poly(ethylene glycol) (PEG) chains. Docetaxel (DTX)-loaded cRGD/TAT CMs were very stable with minimal drug leakage under physiological conditions, whereas rapid DTX release took place in a reductive environment. Flow cytometry showed that the cRGD/TAT CMs with molar ratios of 20% cRGD and 10% TAT (cRGD20/TAT10 CMs) were selectively and efficiently taken up by α_νβ₃-overexpressing U87MG glioma cells, with 8.3-fold and 18.3-fold higher uptake than cRGD20 CMs and PEG CMs, respectively. DTX-loaded cRGD20/TAT10 CMs exhibited a high cytotoxicity in U87MG cells, leading to rapid apoptosis of the tumor cells. Uptake mechanism studies revealed that cRGD20/TAT10 CMs mainly employed the caveolae-mediated endocytotic pathway and efficiently escaped from the lysosomes. Notably, cRGD20/TAT10 CMs had a long circulating time of 6.25 h in vivo, due to cross-linking of the micelles and shielding of the TAT peptide. Moreover, DTX-loaded cRGD20/TAT10 CMs exhibited a significantly higher accumulation and deeper penetration in subcutaneous U87MG glioma tissue compared to cRGD20 CMs and PEG CMs, leading to superior antitumor efficacy in vivo. Therefore, this dual-ligand strategy provides an effective way to realize tumor-specific penetration and inhibition.

Co-ordinated overexpression of SIRT1 and STAT3 is associated with poor survival outcome in gastric cancer patients

In many gastric cancer patients, the disease is diagnosed in an advanced stage and therefore the mortality levels are high. Because there is a need to identify novel early diagnostic and prognostic biomarkers, we tested whether SIRT1 and STAT3 are good candidates. Towards this, we used patient tissues representing different stages of gastric cancer including gastric pre-cancerous lesions, early gastric cancer, and advanced gastric cancer, and probed SIRT1, STAT3 and phosphorylated STAT3 (pSTAT3) levels using immunohistochemistry. Our results revealed upregulated expression of SIRT1 in all stages of gastric cancer compared with noncancerous gastric mucosa, suggesting that high SIRT1 levels are likely involved in establishing gastric neoplasticity. However, STAT3 and pSTAT3 levels remained low until the gastric mucosa reached the tumor stage. Moreover, co-ordinated high expression of SIRT1 and STAT3 predicted poor overall survival for advanced gastric cancer patients. In addition, through analysis of gastric cancer patients from the TCGA dataset, we identified SIRT2 as an independent prognostic factor in gastric cancer patients. We postulate that SIRT1 and STAT3 are potential early diagnostic and prognostic markers of gastric cancer. Our study also shows that SIRT1 acts a gatekeeper during gastric tumorigenesis.

Long non-coding RNA XIST promotes cell growth and metastasis through regulating miR-139-5p mediated Wnt/β-catenin signaling pathway in bladder cancer

Bladder cancer is one of the most common urological malignancy all over the world. Recently, long non-coding RNA (lncRNA) XIST has been identified as an oncogenic gene in several type of cancers. However, the expression level and functional role of XIST in bladder cancer remain largely unknown. In the present study, we found that XIST was significantly up-regulated in bladder cancer tissues and cell lines, and was correlated with poor prognosis of bladder cancer patients. Furthermore, XIST knockdown significantly inhibited bladder cancer cell growth and metastasis in vitro and tumor growth in vivo. We also demonstrated that XIST acted as a competing endogenous RNA for miR-139-5p and repression of miR-139-5p could restore the inhibitory effects on bladder cancer cells induced by XIST shRNA. In addition, we identified that Wnt1 was a direct target of miR-139-5p, and XIST played the oncogenic role in bladder cancer by activating the Wnt/β-catenin signaling pathway. Taken together, our study suggested that lncRNA XIST may serve as a prognostic biomarker and a potential therapeutic target for bladder cancer.

Emission characteristics of PBDEs during flame-retardant plastics extruding process: field investigation and laboratorial simulation

Though mechanical recycling of WEEE plastics is supposed to be a promising method, PBDEs release and the resulting contamination during its processing remain unclear yet. The distribution of PBDEs pollution in production lines was investigated from two flame-retardant plastic modification plants in Southern China. This was followed by laboratory simulation experiments to characterize the emission processes. PBDEs concentrations ranged from 37 to 31,305 ng/L in cooling water and from 40,043 to 216,653 ng/g dry wt in solid samples taken during the field investigation. In the laboratory simulation, concentrations ranged from 146 to 433 ng/L in cooling water and from 411,436 to 747,516 ng/Nm³ in flue gas. All samples were dominated by BDE-209 among the congeners. Temperatures and impurities in plastic substrate can significantly affect PBDEs release. Special attention should be paid to the risks of water directly discharge from the cooling system, especially for the biological sludge and sediments, as well as flue gas emissions to the environment.

The safety and efficacy of oral anticoagulants with dual versus single antiplatelet therapy in patients after percutaneous coronary intervention: A meta-analysis

BACKGROUND

A growing number of patients require oral anticoagulant (OAC) after undergoing percutaneous coronary intervention (PCI) with stent implantation due to the development of atrial fibrillation, but the optimal antithrombotic regimen remains controversial in these patients.

METHODS

We systematically searched PUBMED, EMBASE, and CENTRAL from inception until September 2016 for randomized controlled trials or cohort studies that evaluated the comparative effects of TT versus DT. Relative risks (RRs) with 95% confidence intervals (95% CIs) were pooled by a random-effects model or a fixed-effects model.

RESULTS

Twelve studies with a total of 30,823 patients were included in this analysis, including 6134 in the TT group and 24,689 in the DT group. No significant differences were found between the TT group and the DT group regarding major adverse cardiovascular events (MACE) (RR = 0.82, 95% CI: 0.58-1.17; I = 87.3%), stroke (RR = 1.08, 95% CI: 0.56-2.07; I = 65.5%), all-cause mortality (RR = 0.90, 95% CI: 0.54-1.51; I = 79.1%), or stent thrombosis (RR = 0.71, 95% CI: 0.41-1.24; I = 12.7%), and lower rates were observed for myocardial infarction (RR = 0.59, 95% CI: 0.50-0.70; I = 31.1%) and major bleeding with TT (RR = 0.86, 95% CI: 0.74-0.99; I = 24.3%). Meanwhile, we also found that compared with TT, OAC with clopidogrel treatment shows equal efficacy and safety outcomes.

CONCLUSION

In patients on OAC undergoing PCI with stent implantation, compared with DT, TT shows equal effectiveness in terms of MACE, stroke, all-cause mortality, and stent thrombosis and lower risks of myocardial infarction and major bleeding. However, similar efficacy and safety outcomes were observed between the TT group and the OAC along with clopidogrel group.

Biodegradable Micelles Based on Poly(ethylene glycol)-b-polylipopeptide Copolymer: A Robust and Versatile Nanoplatform for Anticancer Drug Delivery

Poly(ethylene glycol)-b-polypeptide block copolymer micelles, with excellent safety, are one of the most clinically studied nanocarriers for anticancer drug delivery. Notably, self-assembled nanosystems based on hydrophobic polypeptides showing typically a low drug loading and burst drug release are limited to preclinical studies. Here, we report that poly(ethylene glycol)-b-poly(α-aminopalmitic acid) (PEG-b-PAPA) block copolymer could be easily prepared with tailored M_n through ring-opening polymerization of α-aminopalmitic acid N-carboxyanhydride (APA-NCA). Interestingly, PEG-b-PAPA copolymers exhibited superb solubility in common organic solvents (including CHCl₃, CH₂Cl₂, and THF), while stable nanomicelles were formed in phosphate buffer, with a small size of 59 nm and a low critical micelle concentration of 2.38 mg/L. These polylipopeptide micelles (Lipep-Ms) allowed facile loading of a potent anticancer drug, docetaxel (DTX), likely due to the existence of a strong interaction between the lipophilic drug and polylipopeptide in the core. Notably, cRGD-peptide-functionalized Lipep-Ms (cRGD-Lipep-Ms) were also obtained with similar biophysical characteristics. The in vitro studies showed efficient cellular uptake of DTX-loaded cRGD-Lipep-Ms by B16F10 cells and fast intracellular drug release due to the enzymatic degradation of PAPA blocks in endo/lysosome, leading to a pronounced anticancer effect (IC₅₀ = 0.15 μg DTX equiv/mL). The in vivo therapy studies showed that DTX-cRGD-Lipep-Ms exhibited superior tumor growth inhibition of B16F10 melanoma, improved survival rate, and little side effects as compared to free DTX. These polylipopeptide micelles appear as a promising and robust nanoplatform for anticancer drug delivery.