MUC-king with HIF May Rewire Pyrimidine Biosynthesis and Curb Gemcitabine Resistance in Pancreatic Cancer

Publication date: 10 July 2017
Source:Cancer Cell, Volume 32, Issue 1
Author(s): Chi V. Dang
In this issue of Cancer Cell, Singh and colleagues report a role for MUC1-induced HIF expression in rewiring ribose synthesis, which drives pyridimine production as a possible resistance mechanism to gemcitabine, adding to complexity and multiple paths to resistance.

Teaser

In this issue of Cancer Cell, Singh and colleagues report a role for MUC1-induced HIF expression in rewiring ribose synthesis, which drives pyridimine production as a possible resistance mechanism to gemcitabine, adding to complexity and multiple paths to resistance.


http://ift.tt/2u7D4Wn

Redefining Hormonal Therapy for Advanced Prostate Cancer: Results from the LATITUDE and CHAARTED Studies

Publication date: 10 July 2017
Source:Cancer Cell, Volume 32, Issue 1
Author(s): Eric J. Small
Two papers published recently in the New England Journal of Medicine describe the utility of abiraterone acetate, an androgen biosynthesis inhibitor, in the early treatment of metastatic prostate cancer. In addition to establishing a new standard of care, these two articles pose a number of important questions for future investigation.

Teaser

Two papers published recently in the New England Journal of Medicine describe the utility of abiraterone acetate, an androgen biosynthesis inhibitor, in the early treatment of metastatic prostate cancer. In addition to establishing a new standard of care, these two articles pose a number of important questions for future investigation.


http://ift.tt/2v66P76

Choose and Use Your Chemical Probe Wisely to Explore Cancer Biology

Publication date: 10 July 2017
Source:Cancer Cell, Volume 32, Issue 1
Author(s): Julian Blagg, Paul Workman
Small-molecule chemical probes or tools have become progressively more important in recent years as valuable reagents to investigate fundamental biological mechanisms and processes causing disease, including cancer. Chemical probes have also achieved greater prominence alongside complementary biological reagents for target validation in drug discovery. However, there is evidence of widespread continuing misuse and promulgation of poor-quality and insufficiently selective chemical probes, perpetuating a worrisome and misleading pollution of the scientific literature. We discuss current challenges with the selection and use of chemical probes, and suggest how biologists can and should be more discriminating in the probes they employ.

Teaser

Small-molecule chemical probes or tools have become progressively more important in recent years as valuable reagents to investigate fundamental biological mechanisms and processes causing disease, including cancer. Chemical probes have also achieved greater prominence alongside complementary biological reagents for target validation in drug discovery. However, there is evidence of widespread continuing misuse and promulgation of poor-quality and insufficiently selective chemical probes, perpetuating a worrisome and misleading pollution of the scientific literature. We discuss current challenges with the selection and use of chemical probes, and suggest how biologists can and should be more discriminating in the probes they employ.


http://ift.tt/2u7Nbu8

Tumor Evolution of Glioma-Intrinsic Gene Expression Subtypes Associates with Immunological Changes in the Microenvironment

Publication date: 10 July 2017
Source:Cancer Cell, Volume 32, Issue 1
Author(s): Qianghu Wang, Baoli Hu, Xin Hu, Hoon Kim, Massimo Squatrito, Lisa Scarpace, Ana C. deCarvalho, Sali Lyu, Pengping Li, Yan Li, Floris Barthel, Hee Jin Cho, Yu-Hsi Lin, Nikunj Satani, Emmanuel Martinez-Ledesma, Siyuan Zheng, Edward Chang, Charles-Etienne Gabriel Sauvé, Adriana Olar, Zheng D. Lan, Gaetano Finocchiaro, Joanna J. Phillips, Mitchel S. Berger, Konrad R. Gabrusiewicz, Guocan Wang, Eskil Eskilsson, Jian Hu, Tom Mikkelsen, Ronald A. DePinho, Florian Muller, Amy B. Heimberger, Erik P. Sulman, Do-Hyun Nam, Roel G.W. Verhaak
We leveraged IDH wild-type glioblastomas, derivative neurospheres, and single-cell gene expression profiles to define three tumor-intrinsic transcriptional subtypes designated as proneural, mesenchymal, and classical. Transcriptomic subtype multiplicity correlated with increased intratumoral heterogeneity and presence of tumor microenvironment. In silico cell sorting identified macrophages/microglia, CD4⁺ T lymphocytes, and neutrophils in the glioma microenvironment. NF1 deficiency resulted in increased tumor-associated macrophages/microglia infiltration. Longitudinal transcriptome analysis showed that expression subtype is retained in 55% of cases. Gene signature-based tumor microenvironment inference revealed a decrease in invading monocytes and a subtype-dependent increase in macrophages/microglia cells upon disease recurrence. Hypermutation at diagnosis or at recurrence associated with CD8⁺ T cell enrichment. Frequency of M2 macrophages detection associated with short-term relapse after radiation therapy.

Graphical abstract

Teaser

Wang et al. define three IDH wild-type glioblastoma-intrinsic gene expression subtypes, which are partly shaped by the tumor immune environment. NF1 deficiency results in increased macrophage/microglia infiltration. Comparison of matched primary and recurrent tumors reveals frequent expression subtype changes.


http://ift.tt/2v6cXMP

HDAC Inhibitors Finally Open Up: Chromatin Accessibility Signatures of CTCL

Publication date: 10 July 2017
Source:Cancer Cell, Volume 32, Issue 1
Author(s): Christopher J. Ott, Catherine J. Wu
In this issue of Cancer Cell, Qu et al. describe the chromatin accessibility profiles of cutaneous T cell lymphoma, with dynamic assessments of response and resistance to histone deacetylase inhibitor therapy. Their "personal regulome" analysis framework reveals chromatin features that may be predictive of clinical response to epigenetic therapy.

Teaser

In this issue of Cancer Cell, Qu et al. describe the chromatin accessibility profiles of cutaneous T cell lymphoma, with dynamic assessments of response and resistance to histone deacetylase inhibitor therapy. Their "personal regulome" analysis framework reveals chromatin features that may be predictive of clinical response to epigenetic therapy.


http://ift.tt/2v6cJ8l

MUC1 and HIF-1alpha Signaling Crosstalk Induces Anabolic Glucose Metabolism to Impart Gemcitabine Resistance to Pancreatic Cancer

Publication date: 10 July 2017
Source:Cancer Cell, Volume 32, Issue 1
Author(s): Surendra K. Shukla, Vinee Purohit, Kamiya Mehla, Venugopal Gunda, Nina V. Chaika, Enza Vernucci, Ryan J. King, Jaime Abrego, Gennifer D. Goode, Aneesha Dasgupta, Alysha L. Illies, Teklab Gebregiworgis, Bingbing Dai, Jithesh J. Augustine, Divya Murthy, Kuldeep S. Attri, Oksana Mashadova, Paul M. Grandgenett, Robert Powers, Quan P. Ly, Audrey J. Lazenby, Jean L. Grem, Fang Yu, José M. Matés, John M. Asara, Jung-whan Kim, Jordan H. Hankins, Colin Weekes, Michael A. Hollingsworth, Natalie J. Sarkova, Aaron R. Sasson, Jason B. Fleming, Jennifer M. Oliveto, Costas A. Lyssiotis, Lewis C. Cantley, Lyudmyla Berim, Pankaj K. Singh
Poor response to cancer therapy due to resistance remains a clinical challenge. The present study establishes a widely prevalent mechanism of resistance to gemcitabine in pancreatic cancer, whereby increased glycolytic flux leads to glucose addiction in cancer cells and a corresponding increase in pyrimidine biosynthesis to enhance the intrinsic levels of deoxycytidine triphosphate (dCTP). Increased levels of dCTP diminish the effective levels of gemcitabine through molecular competition. We also demonstrate that MUC1-regulated stabilization of hypoxia inducible factor-1α (HIF-1α) mediates such metabolic reprogramming. Targeting HIF-1α or de novo pyrimidine biosynthesis, in combination with gemcitabine, strongly diminishes tumor burden. Finally, reduced expression of TKT and CTPS, which regulate flux into pyrimidine biosynthesis, correlates with better prognosis in pancreatic cancer patients on fluoropyrimidine analogs.

Graphical abstract

Teaser

Shukla et al. identify that HIF-1α mediates increased glycolytic flux and de novo pyrimidine biosynthesis, leading to gemcitabine resistance in pancreatic cancer cells. Targeting HIF-1α or de novo pyrimidine biosynthesis increases the efficacy of gemcitabine.


http://ift.tt/2u7vjje

Oncogenic Activation of the RNA Binding Protein NELFE and MYC Signaling in Hepatocellular Carcinoma

Publication date: 10 July 2017
Source:Cancer Cell, Volume 32, Issue 1
Author(s): Hien Dang, Atsushi Takai, Marshonna Forgues, Yotsowat Pomyen, Haiwei Mou, Wen Xue, Debashish Ray, Kevin C.H. Ha, Quaid D. Morris, Timothy R. Hughes, Xin Wei Wang
Global transcriptomic imbalance is a ubiquitous feature associated with cancer, including hepatocellular carcinoma (HCC). Analyses of 1,225 clinical HCC samples revealed that a large numbers of RNA binding proteins (RBPs) are dysregulated and that RBP dysregulation is associated with poor prognosis. We further identified that oncogenic activation of a top candidate RBP, negative elongation factor E (NELFE), via somatic copy-number alterations enhanced MYC signaling and promoted HCC progression. Interestingly, NELFE induces a unique tumor transcriptome by selectively regulating MYC-associated genes. Thus, our results revealed NELFE as an oncogenic protein that may contribute to transcriptome imbalance in HCC through the regulation of MYC signaling.

Graphical abstract

Teaser

Dang et al. show that a large numbers of RNA binding proteins (RBPs) are dysregulated in hepatocellular carcinoma (HCC) and that NELFE, an RBP, enhances MYC-induced HCC development by regulating the binding of MYC to target promoters and the mRNA stability of several MYC-regulated genes.


http://ift.tt/2u7W4UJ

Stabilization of the c-Myc Protein by CAMKIIγ Promotes T Cell Lymphoma

Publication date: 10 July 2017
Source:Cancer Cell, Volume 32, Issue 1
Author(s): Ying Gu, Jiawei Zhang, Xiaoxiao Ma, Byung-wook Kim, Hailong Wang, Jinfan Li, Yi Pan, Yang Xu, Lili Ding, Lu Yang, Chao Guo, Xiwei Wu, Jun Wu, Kirk Wu, Xiaoxian Gan, Gang Li, Ling Li, Stephen J. Forman, Wing-Chung Chan, Rongzhen Xu, Wendong Huang
Although high c-Myc protein expression is observed alongside MYC amplification in some cancers, in most cases protein overexpression occurs in the absence of gene amplification, e.g., T cell lymphoma (TCL). Here, Ca²⁺/calmodulin-dependent protein kinase II γ (CAMKIIγ) was shown to stabilize the c-Myc protein by directly phosphorylating it at serine 62 (S62). Furthermore, CAMKIIγ was shown to be essential for tumor maintenance. Inhibition of CAMKIIγ with a specific inhibitor destabilized c-Myc and reduced tumor burden. Importantly, high CAMKIIγ levels in patient TCL specimens correlate with increased c-Myc and pS62-c-Myc levels. Together, the CAMKIIγ:c-Myc axis critically influences the development and maintenance of TCL and represents a potential therapeutic target for TCL.

Graphical abstract

Teaser

T cell lymphomas (TCL) overexpress the c-Myc protein without MYC rearrangements or amplification. Gu et al. show that CAMKIIγ stabilizes c-Myc by phosphorylating it at Ser62, that the CAMKIIγ level positively correlates with the c-Myc level in patient TCL, and that inhibition of CAMKIIγ reduces TCL burden in mice.


http://ift.tt/2v64nNN

Bacillus Calmette-Guérin (BCG) vaccination patterns in the province of Québec, Canada, 1956–1974

Publication date: Available online 10 July 2017
Source:Vaccine
Author(s): Marie-Claude Rousseau, Florence Conus, Khady Kâ, Mariam El-Zein, Marie-Élise Parent, Dick Menzies
BackgroundIn the province of Québec, Canada, the Bacillus Calmette-Guérin (BCG) vaccine was offered to newborns and school-age children from the 1950s to mid-1970s in an organized tuberculosis prevention program.ObjectiveWe aimed to describe the annual rates of skin test administration, proportion of skin tests that were positive, and rates of BCG vaccination from 1956 to 1974 according to age, sex, and administrative region.MethodsFor rates, numerators were extracted from the Québec BCG Vaccination Registry whereas population denominators were obtained from the Canadian Census and governmental publications. Time trends were assessed with linear regression.ResultsA total of 2,755,336 skin tests and 2,531,366 BCG vaccinations were administered. Yearly rates of skin tests, routinely administered before vaccination among all except newborns, were highest among children aged 5–9 (9.3 per 100) and 10–14years (7.9 per 100). The proportion of positive skin tests varied greatly by age, ranging from 10.2% among children <1year to 67.2% among adults ≥20years. The vast majority of individuals who had a negative skin test were subsequently vaccinated, whereas those with a positive result were not, as per recommended guidelines. The average annual vaccination rate was highest among children aged <1year (43.8 per 100) and 5–9year-olds (6.9 per 100). There were salient differences in immunization rates, including positive skin tests and vaccinations, across administrative regions but no difference by sex.ConclusionThis is the first comprehensive description of the tuberculosis prevention program in Québec which offered free, non-mandatory BCG vaccination. Our results confirm that the targeted groups, newborns and school-age children, were preferentially reached. Socioeconomic, demographic, and organizational factors may explain regional differences in immunization rates. Beyond presenting a historical context for this vaccination campaign, our findings are relevant to contemporary uses of the Québec BCG Vaccination Registry in epidemiological research.



http://ift.tt/2tCuCOf

Combination vaccine strategies to prevent enteric infections

Publication date: Available online 10 July 2017
Source:Vaccine
Author(s): Richard Walker, Peter Dull
New vaccine candidates entering the current routine immunization schedule can best be accommodated as combination vaccines. A combined Shigella and enterotoxigenic E. coli (ETEC) vaccine could greatly benefit children in disease-endemic areas. New candidates are getting closer to being able to meet these needs, but they raise numerous strategic questions related to presentation, formulation, and regulatory approach. The "Combination Vaccine Strategies to Prevent Enteric Infections" workshop at the 2016 Vaccines Against Shigella and ETEC (VASE) Conference examined some of the considerations for developing such vaccines against enteric pathogens.



http://ift.tt/2tCsru4

Silk fibroin degumming affects scaffold structure and release of macromolecular drugs

Publication date: 30 August 2017
Source:European Journal of Pharmaceutical Sciences, Volume 106
Author(s): Kira Nultsch, Oliver Germershaus
Silk fibroin (SF) is a natural polymer with tremendous potential as a matrix for drug delivery systems as well as for tissue engineering. Silk sericin (SS) removal (degumming) is a critical step during SF purification, potentially affecting SF integrity and resulting in structural changes such as partial hydrolysis and inhibition of micelle formation. In addition to SF composition itself, the molecular weight and charge of encapsulated drugs may significantly affect drug release from SF matrices. The effect of these parameters on drug release was investigated by varying SF degumming time and charge of the model compound encapsulated in SF films. With increasing degumming time, average SF molecular weight decreased, molecular weight distribution became broader and formation of SF micelles was impaired. However, β-sheet content was not affected by degumming time, suggesting that degradation occurred mainly in hydrophilic domains of SF. The release of differently charged dextran derivatives, used as macromolecular model drugs, was significantly affected by SF degumming. Release of neutral dextran increased with increasing degumming time. In contrast, negatively charged dextran showed an inverse effect potentially due to reduced SF charge density with increased degumming time. Interestingly, positively charged dextran were shown to partly form polyelectrolyte complexes with SF by isothermal titration calorimetry but also exhibited phase separation during film drying resulting in fast burst release. These results demonstrate that both, SF preparation as well as drug charge significantly affect drug release from SF matrices.

Graphical abstract

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Antitumor efficacy of Lf modified daunorubicin plus honokiol liposomes in treatment of brain glioma

Publication date: 30 August 2017
Source:European Journal of Pharmaceutical Sciences, Volume 106
Author(s): Shuang Liu, Shi-meng Zhang, Rui-jun Ju, Yao Xiao, Xin Wang, Xiao-li Song, Li-yan Gu, Lan Cheng, Xue-tao Li, Gui-rong Chen
Malignant brain glioma is the most common and aggressive type of primary intracranial neoplasm. Regular chemotherapy cannot eradicate brain glioma cells and the residual glioma cells could form vasculogenic mimicry (VM) channels under hypoxic conditions to provide nutrients for tumor cell invasion. In addition, the existence of the blood-brain barrier (BBB) restricts most antitumor drugs into brain glioma. In this study, we developed a kind of lactoferrin (Lf) modified daunorubicin plus honokiol liposomes to transport antitumor drugs across BBB, eliminate the VM channels and block tumor cell invasion. The evaluations were performed on BBB model, brain glioma cells and glioma-bearing mice. In vitro results showed that the targeting liposomes with suitable physicochemical property could enhance the drug transportation acrossing the BBB, inhibit C6 cells invasion and destroy VM channels. Action mechanism studies indicated that Lf modified daunorubicin plus honokiol liposomes could activate apoptotic enzymes caspase 3 as well as down-regulate VM protein indicators (PI3K, MMP-2, MMP-9, VE-Cadherin and FAK). In vivo results displayed the targeting liposomes improved accumulation in brain tumor tissue and exhibited obvious antitumor efficacy. Therefore, Lf modified daunorubicin plus honokiol liposomes could be used as a potential therapy for treatment of brain glioma.

Graphical abstract

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Pharmacological evaluation and molecular docking of new di-tert-butylphenol compound, LQFM-091, a new dual 5-LOX/COX inhibitor

Publication date: 30 August 2017
Source:European Journal of Pharmaceutical Sciences, Volume 106
Author(s): Roberta Campos Lino, Daiany Priscila Bueno da Silva, Iziara Ferreira Florentino, Dayane Moreira da Silva, José Luís Rodrigues Martins, Daniel da Costa Batista, Karla Carneiro de Siqueira Leite, Bianca Villavicencio, Géssica A. Vasconcelos, Andreia Luiza Pereira Silva, Renato Ivan de Ávila, Hugo Verli, Marize Campos Valadares, Eric de Souza Gil, Boniek G. Vaz, Luciano M. Lião, Ricardo Menegatti, Elson Alves Costa
Dual 5-LOX/COX inhibitors are potential new dual drugs to treat inflammatory conditions. This research aimed to design, synthesis and to evaluate the anti-inflammatory and antinociceptive effects of the new compound, which is derived from nimesulide and darbufelone lead compounds. The new dual inhibitor 5-LOX/COX has the possible advantage of gastrointestinal safety. A voltammetric experiment was conducted to observe the drug's antioxidative effect. A formalin test, a hot plate test and carrageenan-induced mechanical hyperalgesia were employed to evaluate the analgesic nature of LQFM-091. To evaluate anti-inflammatory activity, we measured edema, leukocyte count, myeloperoxidase activity and cytokines levels in carrageenan-induced inflammation tests. We elucidated the underlying mechanisms by assessing the interaction the with COXs and LOX enzymes by colorimetric screening assay and molecular docking. The lethal dose (LD50) was estimated using 3T3 Neutral Red Uptake assay. Our results indicate that the LQFM-091 prototype is a powerful antioxidant, as well as able to inhibit COX-1, COX-2 and LOX activities. LQFM091 was classified in GHS category 4 (300<LD50<2000mg/Kg). This prototype showed analgesic activity in the formalin test and decreased carrageenan-induced mechanical hyperalgesia. Furthermore, LQFM-091 reduced the paw edema induced by carrageenan and reduced the leukocyte count, myeloperoxidase activity, TNF-α and IL-1β levels in the pleural exudate. Another interesting finding was the absence of gastrointestinal lesions. These data indicate that LQFM-091 produced antinociceptive and anti-inflammatory effects while maintaining gastrointestinal safety. Furthermore, this compound presented a safe toxicological profile. Blocked COXs and LOX enzymes are important targets for manipulating the mechanism of this compound.

Graphical abstract

http://ift.tt/2u2QdAh

Impact of capillary flow hydrodynamics on carrier-mediated transport of opioid derivatives at the blood-brain barrier, based on pH-dependent Michaelis-Menten and Crone-Renkin analyses

Publication date: 30 August 2017
Source:European Journal of Pharmaceutical Sciences, Volume 106
Author(s): Siti R. Yusof, N. Joan Abbott, Alex Avdeef
Most studies of blood-brain barrier (BBB) permeability and transport are conducted at a single pH, but more detailed information can be revealed by using multiple pH values. A pH-dependent biophysical model was applied to the mechanistic analysis of published pH-dependent BBB luminal uptake data from three opioid derivatives in rat: pentazocine (Suzuki et al., 2002a, 2002b), naloxone (Suzuki et al., 2010a), and oxycodone (Okura et al., 2008). Two types of data were processed: in situ brain perfusion (ISBP) and brain uptake index (BUI). The published perfusion data were converted to apparent luminal permeability values, Papp, and analyzed by the pCEL-X program (Yusof et al., 2014), using the pH-dependent Crone-Renkin equation (pH-CRE) to determine the impact of cerebrovascular flow on the Michaelis-Menten transport parameters (Avdeef and Sun, 2011). For oxycodone, the ISBP data had been measured at pH7.4 and 8.4. The present analysis indicates a 7-fold lower value of the cerebrovascular flow velocity, Fpf, than that expected in the original study. From the pyrilamine-inhibited data, the flow-corrected passive intrinsic permeability value was determined to be P0=398×10⁻⁶cm·s⁻¹. The uptake data indicate that the neutral form of oxycodone is affected by a transporter at pH8.4. The extent of the cation uptake was less certain from the available data. For pentazocine, the brain uptake by the BUI method had been measured at pH5.5, 6.5, and 7.4, in a concentration range 0.1–40mM. Under similar conditions, ISBP data were also available. The pH-CRE determined values of Fpf from both methods were nearly the same, and were smaller than the expected value in the original publication. The transport of the cationic pentazocine was not fully saturated at pH5.5 at 40mM. The transport of the neutral species at pH7.4 appeared to reach saturation at 40mM pentazocine concentration, but not at 12mM. In the case of naloxone, a pH-dependent Michaelis-Menten equation (pH-MME) analysis of the data indicated a smooth sigmoidal transition from a higher capacity uptake process affecting cationic naloxone (pH5.0–7.0) to a lower capacity uptake process affecting the neutral drug (pH8.0–8.5), with cross-over point near pH7.4. Evidently, measurements at multiple pH values can reveal important information about both cerebrovascular flow and BBB transport kinetics.

Graphical abstract

http://ift.tt/2u2UjIJ

Editorial board members

Publication date: 30 August 2017
Source:European Journal of Pharmaceutical Sciences, Volume 106





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Antimicrobial activity of polymyxin-loaded solid lipid nanoparticles (PLX-SLN): Characterization of physicochemical properties and in vitro efficacy

Publication date: 30 August 2017
Source:European Journal of Pharmaceutical Sciences, Volume 106
Author(s): Patrícia Severino, Elisânia F. Silveira, Kahynna Loureiro, Marco V. Chaud, Danilo Antonini, Marcelo Lancellotti, Victor Hugo Sarmento, Classius F. da Silva, Maria Helena A. Santana, Eliana B. Souto
Antimicrobial resistance is a current public health concern, limiting the available therapeutic options used for the treatment of common bacterial infections. The development of new drug entities via biotechnological processes is however expensive and time-consuming. Therefore, old antimicrobial agents have been recovered for clinical use. An example of these drugs is polymyxin, which is known for its serious adverse side effects, such as nephrotoxicity, neurotoxicity and promotion of skin pigmentation. To overcome these limitations, the use of biodegradable nanoparticles has been proposed to allow site-specific targeting, increasing the drug's bioavailability and decreasing its side effects. The aim of this work was the development of an optimized pharmaceutical formulation composed of solid lipid nanoparticles (SLN) loading polymyxin B sulphate (PLX) for the treatment of bacterial infections. The PLX-loaded SLN were produced by a double emulsion method (w/o/w), obtaining particles with a mean size of approximately 200nm, polydispersity of 0.3 and zeta potential of −30mV. The encapsulation efficiency reached values above 90% for all developed formulations. SLN remained stable for a period of 6months of storage at room temperature. The occlusive properties of the SLN was shown to be dependent on the type of lipid, while the antimicrobial properties of PLX-loaded SLN were effective against resistant strains of Pseudomonas aeruginosa. Results from the differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and small angle X-ray scattering (SAXS) analyses confirmed the crystallinity of the inner SLN matrices, suggesting the capacity of these particles to modify the release profile of the loaded drug.

Graphical abstract

http://ift.tt/2sK7NoW

Evaluation of anti-diabetic activity of glycyrrhizin-loaded nanoparticles in nicotinamide-streptozotocin-induced diabetic rats

Publication date: 30 August 2017
Source:European Journal of Pharmaceutical Sciences, Volume 106
Author(s): Ruma Rani, Shakti Dahiya, Dinesh Dhingra, Neeraj Dilbaghi, Ki-Hyun Kim, Sandeep Kumar
Glycyrrhizin is an active constituent of the roots and rhizomes of Glycyrrhiza glabra and has anti-hyperglycemic effects. In this study, nanoparticles (NPs) loaded with glycyrrhizin or metformin were evaluated in vivo for their anti-hyperglycemic potency towards type-II diabetes in rats. The NPs were produced via the ionotropic gelation method using the biocompatible polymers chitosan and gum arabic. The polymer concentration was optimized using the 3² factorial method to acquire both minimum particle size and maximum encapsulation efficiency. The NPs were then characterized with respect to particle size, encapsulation efficiency, stability, chemical interactions, and in vitro drug dissolution profiles using spectroscopic and microscopic analysis. Furthermore, glycyrrhizin and metformin and their nanoformulations were administered for 21 successive days to diabetic rats. Glycyrrhizin-loaded NPs had significant anti-diabetic effects even though they contained approximately one quarter of the dosage relative to the pure form.

Graphical abstract

http://ift.tt/2sKoJLK

Development of a Sigma-2 Receptor affinity filter through a Monte Carlo based QSAR analysis

Publication date: 30 August 2017
Source:European Journal of Pharmaceutical Sciences, Volume 106
Author(s): Antonio Rescifina, Giuseppe Floresta, Agostino Marrazzo, Carmela Parenti, Orazio Prezzavento, Giovanni Nastasi, Maria Dichiara, Emanuele Amata
For the first time in sigma-2 (σ2) receptor field, a quantitative structure–activity relationship (QSAR) model has been built using pKi values of the whole set of known selective σ2 receptor ligands (548 compounds), taken from the Sigma-2 Receptor Selective Ligands Database (S2RSLDB) (http://ift.tt/2sJY6qr), through the Monte Carlo technique and employing the software CORAL. The model has been developed by using a large and structurally diverse set of compounds, allowing for a prediction of different populations of chemical compounds endpoint (σ2 receptor pKi). The statistical quality reached, suggested that model for pKi determination is robust and possesses a satisfactory predictive potential. The statistical quality is high for both visible and invisible sets. The screening of the FDA approved drugs, external to our dataset, suggested that sixteen compounds might be repositioned as σ2 receptor ligands (predicted pKi≥8). A literature check showed that six of these compounds have already been tested for affinity at σ2 receptor and, of these, two (Flunarizine and Terbinafine) have shown an experimental σ2 receptor pKi>7. This suggests that this QSAR model may be used as focusing screening filter in order to prospectively find or repurpose new drugs with high affinity for the σ2 receptor, and overall allowing for an enhanced hit rate respect to a random screening.

Graphical abstract

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A delayed proinflammatory response of human preadipocytes to PCB126 is dependent on the aryl hydrocarbon receptor

Abstract

Inflammation in adipose tissue is recognized as a causative factor in the development of type II diabetes. Adipocyte hypertrophy as well as bacterial and environmental factors have been implicated in causing inflammation in mature adipocytes. Exposure to persistent organic pollutants such as polychlorinated biphenyls (PCBs) has been associated with the development of type II diabetes. We show here that PCB126, a dioxin-like PCB, activates a robust proinflammatory state in fat cell precursors (preadipocytes). The response was found to be dependent on aryl hydrocarbon receptor (AhR) activation, although induction of the response was delayed compared to upregulation of CYP1A1, a classic AhR-responsive gene. Treatment of preadipocytes with a nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) inhibitor partially attenuated the PCB126-induced inflammatory response and partly, but not completely, ameliorated disruption of adipogenesis caused by PCB126. Our results indicate a role for PCB126 in mediating an inflammatory response through AhR in preadipocytes that interferes with adipogenesis.

http://ift.tt/2u2Q7J8

Study of chlordecone desorption from activated carbons and subsequent dechlorination by reduced cobalamin

Abstract

Since 1972, the French departments of Guadeloupe and Martinique have intensively used organochlorinated pesticides such as chlordecone (CLD) and hexachlorocyclohexane (HCH) isomers to prevent the proliferation of banana weevil (Cosmopolite sordidus). These molecules are stable in the environment, leading to a continuous contamination of soils, water, and food chain in the banana-producing areas. In these polluted areas, water treatment plants are equipped with activated carbon (AC) filters. In order to improve treatment of CLD-contaminated waters by AC, CLD adsorption and desorption kinetic studies are carried out using different ACs produced from sugar cane bagasse as adsorbents and subsequent CLD degradation is performed using reduced vitamin B12 (VB12). A GC-MS method for CLD quantification is as well optimized. This study shows that bagasse ACs are able to capture the pollutant, leading to a CLD concentration decrease from 1 to 73 μg L⁻¹, with an adsorption capacity of 162 μg mg⁻¹. Adsorption capacity increase with the temperature indicates an endothermic process. Polar solvents favor CLD desorption from ACs, suggesting hydrogen bonding between CLD and surface groups of ACs, the best solvent for chemical desorption being ethanol. Subsequent degradation of CLD in ethanol is performed using vitamin B12 reduced by either 1,4-dithiotreitol (DTT) or zerovalent zinc, leading to 90% of CLD removal and to the molecule cage structure opening for formation of a pentachloroindene intermediate product, characterized by GC MS/MS. A pathway for pentachloroindene formation from CLD is proposed.

http://ift.tt/2sKd93B