A novel colorimetric triple-helix molecular switch aptasensor based on peroxidase-like activity of gold nanoparticles for ultrasensitive detection of lead(ii)

Lead (Pb) is a serious environmental contaminant and one of the most toxic heavy metals.

Nanomaterial-based cocaine aptasensors

Up to now, many different methods have been developed for detection of cocaine, but most of these methods are usually time-consuming, tedious and require special or expensive equipment. Therefore, the development of simple, sensitive and rapid detection methods is necessary. In the last decade, aptamers have been used as a new biosensor platform for detection of cocaine in different samples. Aptamers are artificial single-stranded DNA or RNA oligonucleotides capable of binding to specific molecular targets with high affinity and if integrated to nanomaterials, it may lead in precise methods for cocaine detection in the common laboratories. In this review, recent advances and applications of aptamer-based biosensors and nanobiosensors, have been updated, paying attention to the use of fluorescence, colorimetric and electrochemical techniques for the detection and quantitative determination of cocaine.

Epithelial cell adhesion molecule aptamer conjugated PEG-PLGA nanopolymersomes for targeted delivery of doxorubicin to human breast adenocarcinoma cell line in vitro

Targeted delivery of anti-cancer agents exclusively to tumor cells introduces an attractive strategy because it increases the therapeutic index compared with untargeted drugs. Aptamer conjugated nanoparticles that can specifically bind to the proteins on a tumor cell surface are capable nanoscale delivery systems for enhancing cellular uptake of chemotherapeutic agents. The epithelial cell adhesion molecule (EpCAM) as a cancer stem cell marker emerges as a versatile target for aptamer-based cancer therapy due to its high expression level in various adenocarcinoma cell lines and its very low expression level in normal cells. We developed EpCAM-targeted PEG-PLGA nanopolymersomes by covalently coupling the EpCAM aptamer to the surface of nanopolymersomes loaded with the anticancer agent doxorubicin via pH gradient method. The results indicated that doxorubicin was entrapped in PEG-PLGA nanopolymersomes with encapsulation efficiency and loading content of 91.25±4.27% and 7.3±0.34%, respectively. Over a period of 5 days, up to 8% of the DOX was released through this system. The doxorubicin-loaded aptamer conjugated nanopolymersomes exhibited efficient cell uptake and internalization, and were significantly more cytotoxic (P<0.01) toward EpCAM-positive tumor cells (MCF-7) than non-targeted nanopolymersomes. Our data suggest that EpCAM-targeted nanopolymersomes will lead to an improved therapeutic index of doxorubicin to EpCAM positive cancer cells.

Effect of Nigella sativa fixed oil on ethanol toxicity in rats

OBJECTIVES

This study was planned to appraise the protective effect of Nigella sativa fixed oil (NSO) against subchronic ethanol induced toxicity in rats.

MATERIALS AND METHODS

Studies were carried out on six groups of six animals each, including control (normal saline, gavage), ethanol (3 g/kg/day, gavage), NSO (0.125, 0.25 and 0.5 ml/Kg/day, IP) plus ethanol and NSO (0.5 ml/Kg/day, IP) groups. Treatments were continued for 4 weeks.

RESULTS

According to data, treatment with NSO attenuated ethanol-induced increased levels of malondialdehyde (MDA), tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6), as well as histopathological changes in liver and kidney tissues. Moreover, NSO improved the level of serum liver enzymes (including alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP) and glutathione (GSH) content in liver and kidney tissues in ethanol-treated rats. Western blot analysis and quantitative real time RT-PCR showed that NSO treatment inhibited apoptosis stimulated by ethanol through decreasing the Bax/Bcl-2 ratio (both protein and mRNA levels), cleaved caspase-3, cleaved caspase-8 and cleaved caspase-9 level in liver and kidney.

CONCLUSION

This study showed that NSO may have protective effects against hepatotoxicity and renal toxicity of ethanol by decreasing lipid peroxidation and inflammation and preventing apoptosis.

Crocin Effects on Human Myeloma Cells Regarding Intracellular Redox State, DNA Fragmentation, and Apoptosis or Necrosis Profile

Background:

Well-documented studies reported several pharmacological properties for crocin, the active compound of Crocus sativus, such as its antitumor, radical scavenging, antidepressant, and memory-enhancing effects.

Objectives:

We aimed to evaluate the possible cytotoxic activity of crocin on B lymphocytes in human myeloma (U266 cell line) after 24- and 48-hour treatment.

Materials and Methods:

For this purpose, cell viability was determined by the colorimetric MTT assay and cell death pattern was evaluated using Annexin V-FITC/propidium iodide (PI) apoptosis detection kit. ROS (reactive oxygen species) production and DNA fragmentation were assessed using 2′,7′-dichlorofluorescein diacetate (DCFH-DA) kit and PI staining, respectively.

Results:

The highest concentration of crocin significantly decreased ROS production after 48 hours of treatment. However, crocin had no effect on the expression level of HSP (Heat shock protein). Additionally, its administration caused a mild decline in cell viability and a mild increase in the population of DNA fragmented cells as well as apoptosis.

Conclusions:

In our study, no prominent effect was seen; therefore, in order to have a better perspective of crocin activity against cancerous cell lines, further studies are highly recommended.

Protective effect of crocin against apoptosis induced by subchronic exposure of the rat vascular system to diazinon

Research has suggested that natural antioxidant, crocin, an active ingredient of saffron, may protect against diazinon (DZN)-induced toxicity. Although increased production of lipid peroxidation by DZN in rat aorta has been shown previously, the effects of DZN on oxidative stress-induced apoptosis in vascular system have not been evaluated. In this study, the effect of crocin on DZN-induced apoptosis in rat vascular system was investigated. The rats were divided into 7 groups: corn oil (control), DZN (15 mg/kg/day, gavage), crocin (12.5, 25, and 50 mg/kg/day, intraperitoneally (i.p.)) + DZN, vitamin E (200 IU/kg, i.p., 3 days a week) + DZN, and crocin (50 mg/kg/day, i.p.). The treatments were continued for 4 weeks. Levels of apoptotic (Bax, caspase 3, and caspase 9) and antiapoptotic proteins (Bcl2) were analyzed by Western blotting. Transcript levels of Bax and Bcl2 genes were determined using quantitative real-time polymerase chain reaction. Results showed DZN-induced apoptosis by activation of caspase 9 and caspase 3 and by increasing the Bax/Bcl2 ratio (both protein and messenger RNA levels). Crocin and vitamin E inhibited apoptosis induced by DZN. In summary, subchronic exposure to DZN induced caspase-mediated apoptosis, and crocin reduced the toxic effects of DZN by inhibiting apoptosis in aortic tissue.

Evaluation of Protein Ubiquitylation in Heart Tissue of Rats Exposed to Diazinon (an Organophosphate Insecticide) and Crocin (an Active Saffron Ingredient): Role of HIF-1α

INTRODUCTION

Organophosphate compounds, such as diazinon (DZN), are widely used in agriculture and can lead to formation of reactive oxygen species (ROS) in cardiovascular system. ROS are highly toxic since they can cause serious changes in proteins including ubiquitylation. Crocin (a carotenoid isolated from saffron), has protective effects against DZN cardiotoxicity. In this study level of total protein ubiquitylation as markers of oxidative stress and level of ubiquitin-HIF-1α and P53, known substrates of ubiquitylation, in rat hearts exposed to DZN and crocin were evaluated.

METHODS

Rats were divided into 7 groups: corn oil (control), DZN (15 mg/kg/day, gavage), crocin (12.5, 25, 50 mg/kg/day, i. p.) plus DZN, vitamin E (200 IU/kg, i. p., 3 days a week) plus DZN and crocin (50 mg/kg/day, i. p.). Treatments were continued for 4 weeks. Total protein ubiquitylation, total HIF-1α and P53 were analyzed by western blotting. Total HIF-1α and P53 were purified by immunoprecipitation (IP) and ubiquitin- HIF-1α and P53 were analyzed by western blotting.

RESULTS

Higher protein ubiquitylation levels were observed in DZN treated rats. Decrease in ubiquitin-HIF-1α was also shown, and leads to higher HIF-1α protein levels in DZN group. Crocin (50 mg/kg) and vit. E protected cells against DZN protein ubiquitylation. Significant differences were not observed between the ubiquitin - P53 and total P53 protein levels.

CONCLUSION

Our results showed that ubiquitylation could be considered as a marker of oxidative stress in rats exposed to DZN. Increase in level of HIF-α may compensate adverse effect of DNZ in rat heart.

Synthesis of AS1411-aptamer-conjugated CdTe quantum dots with high fluorescence strength for probe labeling tumor cells

In this paper, we report microwave-assisted, one-stage synthesis of high-quality functionalized water-soluble cadmium telluride (CdTe) quantum dots (QDs). By selecting sodium tellurite as the Te source, cadmium chloride as the Cd source, mercaptosuccinic acid (MSA) as the capping agent, and a borate-acetic acid buffer solution with a pH range of 5-8, CdTe nanocrystals with four colors (blue to orange) were conveniently prepared at 100 °C under microwave irradiation in less than one hour (reaction time: 10-60 min). The influence of parameters such as the pH, Cd:Te molar ratio, and reaction time on the emission range and quantum yield percentage (QY%) was investigated. The structures and compositions of the prepared CdTe QDs were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, selective area electron diffraction, and X-ray powder diffraction experiments. The formation mechanism of the QDs is discussed in this paper. Furthermore, AS1141-aptamer-conjugated CdTe QDs in the U87MG glioblastoma cell line were assessed with a fluorescence microscope. The obtained results showed that the best conditions for obtaining a high QY of approximately 87% are a pH of 6, a Cd:Te molar ratio of 5:1, and a 30-min reaction time at 100 °C under microwave irradiation. The results showed that AS1141-aptamer-conjugated CdTe QDs could enter tumor cells efficiently. It could be concluded that a facile high-fluorescence-strength QD conjugated with a DNA aptamer, AS1411, which can recognize the extracellular matrix protein nucleolin, can specifically target U87MG human glioblastoma cells. The qualified AS1411-aptamer-conjugated QDs prepared in this study showed excellent capabilities as nanoprobes for cancer targeting and molecular imaging.

Rabbit nasal immunization against influenza by dry-powder form of chitosan nanospheres encapsulated with influenza whole virus and adjuvants

Influenza virus is one of the main causes of respiratory diseases in human. Although different vaccines have been produced during past decades, there is still a huge demand for a safe influenza vaccine with the ability to induce mucosal immune responses and sufficient protection, especially in elderly patients. In this study, chitosan nanospheres were employed as the drug delivery system. Influenza virus, CpG oligodeoxynucleotide (CpG ODN) and Quillaja saponins (QS) were incorporated in this nanospheric system. Three doses of dry powder nanosphere vaccine were nasally administered to rabbits on days 0, 45 and 60, followed by a final booster injection on day 75. Both humoral and cellular immune responses were investigated. Hemagglutination inhibition (HI) antibody titer was elevated in all groups compared to the control group at the end of vaccination in rabbits receiving nanospheres loaded with virus and CpG, CH(WV+CpG) (P<0.001). Rabbit serum IgG raised significantly in all the vaccinated groups, with the highest responses in CH(WV+CpG) group. CH(WV+CpG) and CH(WV) induced significant sIgA titers (P<0.001). CpG adjuvant also showed a prominent role in the stimulation and secretion of of IL-2 and IFN-γ cytokines (3 and 3.5 fold increase, respectively). Finally, as CH(WV+CpG) depicted to be effective in induction of humoral and cellular immune responses after nasal administration, this nanoparticulate adjuvant could be identified as an efficient adjuvant/delivery system for mucosal immunization against influenza virus.

Conformational switch of insulin-binding aptamer into G-quadruplex induced by K⁺ and Na⁺: an experimental and theoretical approach

Guanine-rich sequences can form the G-quadruplex structure in the presence of specific metal ions. Here, circular dichroism, UV-vis absorption, fluorescence, and molecular dynamics simulation studies revealed that insulin-binding aptamer (IBA) could form an intramolecular G-quadruplex structure after binding K(+). Circular dichroism (CD) spectra demonstrated that IBA could fold into a parallel G-quadruplex with a strong positive peak at 263 nm. Analysis of equilibrium titration data revealed that cation binding was cooperative with the Hill coefficient of 2.01 in K(+) and 1.90 in Na(+). Thermal denaturation assays indicated that K(+)-induced G-quadruplex is more stable than Na(+)-induced structure. Folding of IBA into G-quadruplex leading to the contact quenching occurs as a result of the formation of a nonfluorescent complex between donor and acceptor. Based on fluorescence quenching of IBA folding, a potassium-sensing aptasensor in the range of 0-1.4 mM was proposed. Since the quenching process was predominantly static, the binding constant and the number of binding sites were determined. In this research, based on the experimental data, the initial model of IBA G-quadruplex was constructed by molecular modeling method. The modeling structure of IBA is an intramolecular parallel-strand quadruplex conformation with two guanine tetrads. The extended molecular dynamics simulation for the model indicated that the G-quadruplex maintains its structure very well in aqueous solution in presence of K(+) in the central cavity. In contrast, it was demonstrated that the G-quadruplex structure of model in the water collapses in absence of this cation.

Proteomics screening of molecular targets of granulocyte colony stimulating factor in the mouse brain and PC12 cell line

AIMS

Granulocyte colony stimulating factor (G-CSF), a new neuroprotective agent, binds to its specific receptors in the brain. In this study we hypothesized that at least a part of G-CSF's neuroprotective effect may be mediated through its interaction with other proteins in the brain.

MAIN METHODS

Using an immunoprecipitation (IP) kit, at first the antibody of G-CSF was covalently crosslinked to protein A/G agarose. Then the mouse brain or PC12 cell lysate mixed with G-CSF was added to the agarose beads plus antibody. After immunoaffinity isolation of target proteins, gel electrophoresis was performed and protein bands were identified using MALDI-TOF/TOF and MASCOT software.

KEY FINDINGS

Our data show that G-CSF physically binds to cellular proteins like sodium/potassium-transporting ATPase, beta actin, aldehyde dehydrogenase, regucalcin and glutathione-s-transferase. These proteins are involved in membrane transportation, cell structure, signal transduction, enzymes involve in calcium related cell signaling and redox homeostasis.

SIGNIFICANCE

Interaction of G-CSF with these proteins can explain some of its pharmacological effects in the CNS.

Ultrasensitive detection of lead (II) based on fluorescent aptamer-functionalized carbon nanotubes

Lead contamination is a serious environmental problem with toxic effects in human. Here, we developed a simple and sensitive sensing method employing ATTO 647N/aptamer-SWNT ensemble for detection of Pb(2+). This method is based on the super quenching capability of single-walled carbon nanotubes (SWNTs), high affinity of the aptamer toward Pb(2+) and different propensities of ATTO 647N-aptamer and ATTO 647N-aptamer/Pb(2+) complex for adsorption on SWNTs. In the absence of Pb(2+), the fluorescence of ATTO 647N-aptamer is efficiently quenched by SWNTs. Upon addition of Pb(2+), the aptamer binds to its target, leading to the formation of a G-quadruplex/Pb(2+) complex and does not interact with SWNTs and ATTO 647N-aptamer starts fluorescing. This sensor exhibited a high selectivity toward Pb(2+) and a limit of detection (LOD) as low as 0.42 nM was obtained. Also this sensor could be applied for detection of Pb(2+) ions in tap water and biological sample like serum with high sensitivity.

Targeted gene delivery with noncovalent electrostatic conjugates of sgc-8c aptamer and polyethylenimine

BACKGROUND

Several strategies have been shown to improve the transfection efficiency of polyethylenimine (PEI) as a nonviral gene delivery vector. In the present study, a nucleic acid aptamer specific for protein tyrosine kinase 7 (PTK7) surface marker, sgc-8c, was conjugated electrostatically to pre-formed 10-kDa PEI/plasmid DNA polyplexes, and the ability of the conjugate to transfer genetic material was evaluated in MOLT-4 human acute lymphoblastic leukemia T-cells, which express PTK7 on their surface.

METHODS

Polyplexes (plasmid DNA-vector conjugates), prepared using PEI-sgc-8c conjugate and pCMVLuc as a reporter gene, were characterized in terms of particle size, surface charge and the extent of DNA condensation. Polyplexes were also evaluated for cytotoxicity using the MTS colorimetric assay, as well as for transfection efficiency in MOLT-4 cells, and compared with the results obtained in U266 cells, which lack cell surface PTK7.

RESULTS

Relative to pDNA/PEI, the size of pDNA/PEI/sgc-8c aptamer polyplexes increased with decreasing zeta potential. In MOLT-4 cells, pDNA/PEI/sgc-8c aptamer polyplexes exhibited an almost six- to eight-fold increase in transfection efficiency compared to that of pDNA/PEI polyplex, indicating that conjugation of sgc-8c aptamer to pre-formed 10-kDa PEI/plasmid DNA polyplexes achieved effective targeting without covalent attachment, whereas receptor-mediated conducted transfection was confirmed by performing a competitive transfection experiment and a cellular uptake study.

CONCLUSIONS

The results of the present study provide an example of the usefulness of a nucleic acid aptamer in the form of noncovalent, electrostatic conjugates as an approach for enhancing the transfection efficiency of a polycation vector such as PEI without significant induced cytotoxicity.

Antidepressant effects of crocin and its effects on transcript and protein levels of CREB, BDNF, and VGF in rat hippocampus

Background

Antidepressants have been shown to affect levels of brain-derived neurotrophic factor (BDNF) and VGF (non-acronymic) whose transcriptions are dependent on cAMP response element binding protein (CREB) in long term treatment. The aim of this study was to verify the subacute antidepressant effects of crocin, an active constituent of saffron (Crocus sativus L.), and its effects on CREB, BDNF, and VGF proteins, transcript levels and amount of active, phosphorylated CREB (P-CREB) protein in rat hippocampus.

Methods

Crocin (12.5, 25, and 50 mg/kg), imipramine (10 mg/kg; positive control) and saline (1 mL/kg; neutral control) were administered intraperitoneally (IP) to male Wistar rats for 21 days. The antidepressant effects were studied using the forced swimming test (FST) on day 21 after injection. Protein expression and transcript levels of genes in the rat hippocampus were evaluated using western blot and quantitative reverse transcription-polymerase chain reaction (qRT-PCR), respectively.

Results

Crocin significantly reduced the immobility time in the FST. Western blot analysis showed that 25 and 50 mg/kg of crocin increased the levels of CREB and BDNF significantly and dose dependently. All doses of crocin increased the VGF levels in a dose-dependent manner. Levels of p-CREB increased significantly by 50 mg/kg dose of crocin. Only 12.5 mg/kg crocin could significantly increase the transcript levels of BDNF. No changes in CREB and VGF transcript levels were observed in all groups.

Conclusions

These results suggest that crocin has antidepressant-like action by increasing CREB, BDNF and VGF levels in hippocampus.

Proteomic screening of molecular targets of crocin

Background

Traditional drug discovery approaches are mainly relied on the observed phenotypic changes following administration of a plant extract, drug candidate or natural product. Recently, target-based approaches are becoming more popular. The present study aimed to identify the cellular targets of crocin, the bioactive dietary carotenoid present in saffron, using an affinity-based method.

Methods

Heart, kidney and brain tissues of BALB/c mice were homogenized and extracted for the experiments. Target deconvolution was carried out by first passing cell lysate through an affinity column prepared by covalently attaching crocin to agarose beads. Isolated proteins were separated on a 2D gel, trypsinized in situ and identified by MALDI-TOF/TOF mass spectrometry. MASCOT search engine was used to analyze Mass Data.

Results

Part of proteome that physically interacts with crocin was found to consist of beta-actin-like protein 2, cytochrome b-c1 complex subunit 1, ATP synthase subunit beta, tubulin beta-3 chain, tubulin beta-6 chain, 14-3-3 protein beta/alpha, V-type proton ATPase catalytic subunitA, 60 kDa heat shock protein, creatine kinase b-type, peroxiredoxin-2, cytochrome b-c1 complex subunit 2, acetyl-coA acetyltransferase, cytochrome c1, proteasome subunit alpha type-6 and proteasome subunit alpha type-4.

Conclusion

The present findings revealed that crocin physically binds to a wide range of cellular proteins such as structural proteins, membrane transporters, and enzymes involved in ATP and redox homeostasis and signal transduction.

Synthesis and molecular modeling of six novel monastrol analogues: evaluation of cytotoxicity and kinesin inhibitory activity against HeLa cell line

Background and the purpose of the study

A common approach in cancer chemotherapy is development of drugs that interrupt the mitosis phase of cell division. Dimethylenastron is a known kinesin inhibitor. In this study, six novel dimethylenastron analogues (4a-f), in which 3-hydroxyphenyl substituent has been replaced with substituted benzylimidazolyl, were synthesized through Biginelli reaction.

Methods

Six novel Biginelli compounds (4a-f) were synthesized through one step Biginelli reaction of imidazole aldehydes (3a-c), dimedone and urea or thioura. In vitro cytotoxicities of prepared compounds were investigated using MTT assay. Furthermore the ELIPA kit was implemented to study inhibitory effects of synthesized compounds on ATPase activity of kinesin by measuring of organic phosphate.

Results

Our results indicated that analogue 4c is the most toxic and analogues 4f, 4b and dimethylenasteron were less cytotoxic in compare with other analogues. On the other hand, analogue 4a, 4b, 4c and 4e showed stronger Kinesin inhibition as compared with analogue 4f and dimethylenasteron. None of synthesized compounds were as potent kinesin inhibitor as Taxol. Docking analysis revealed that hydrogen bond formation and hydrophobic interactions were the key factors affecting inhibitory effects of these compounds.

Conclusion

Newly synthesized compounds were found to have moderate to good cytotoxicity against HeLa cancer cell. Our results may be helpful in further design of dihydropyrimidine as potential anticancer agents.

Effect of exposure to diazinon on adult rat’s brain

Diazinon (DZN), a commonly used agricultural organophosphate insecticide, is one of the major concerns for human health. This study was planned to investigate neurotoxic effects of subacute exposure to DZN in adult male Wistar rats. Animals received corn oil as control and 15 and 30 mg/kg DZN orally by gastric gavage for 4 weeks. The cerebrum malondialdehyde and glutathione (GSH) contents were assessed as biomarkers of lipid peroxidation and nonenzyme antioxidants, respectively. Moreover, activated forms of caspase 3, -9, and Bax/Bcl-2 ratios were evaluated as key apoptotic proteins. Results of this study suggested that chronic administration of DZN did not change lipid peroxidation and GSH levels significantly in comparison with control. Also, the active forms of caspase 3 and caspase 9 were not significantly altered in DZN-treated rat groups. Moreover, no significant changes were observed in Bax and Bcl-2 ratios. This study indicated that generation of reactive oxygen species was probably modulated by intracellular antioxidant system. In conclusion, subacute oral administration of DZN did not alter lipid peroxidation. Moreover, apoptosis induction was not observed in rat brain.

Pyrimido[5,4-e]tetrazolo[5,1-b][1,3,4]thiadiazines as a new heterocyclic system

Six novel 2-substituted pyrimido[5,4- e]tetrazolo[5,1- b][1,3,4]thiadiazines were prepared via a multistep synthetic sequence beginning with 5-bromo-2,4-dichloro-6-methylpyrimidine.

Epirubicin loaded super paramagnetic iron oxide nanoparticle-aptamer bioconjugate for combined colon cancer therapy and imaging in vivo

Every year a large number of new cases of colorectal cancer are diagnosed in the world. Application of Epirubicin (Epi) in treatment of cancer has been limited due to its cardiotoxicity. Specific delivery of chemotherapy drugs is an important factor in reducing the side effects of drugs used in chemotherapy. Enhanced permeability, retention effect and magnetic resonance (MR) traceability of super paramagnetic iron oxide nanoparticles (SPION) make them a great candidate in cancer therapy and imaging. In this study, Epirubicin-5TR1 aptamer-SPION tertiary complex was evaluated for the imaging and treatment of murine colon carcinoma cells (C26 cells, target). For cytotoxic studies (MTT assay), C26 and CHO-K1 (Chinese hamster ovary cells, nontarget) cells were treated with either Epi or Epi-Apt-SPION tertiary complex. Internalization was evaluated by flow cytometry. Finally, Apt-SPION bioconjugate was used for imaging of cancer in vivo. Flow cytometric analysis showed that the tertiary complex was internalized effectively to C26 cells, but not to CHO-K1 cells. Cytotoxicity of Epi-Apt-SPION tertiary complex also confirmed internalization data. The complex was less cytotoxic in CHO-K1 cells when compared to Epi alone. No significant change in viability between Epi- and complex-treated C26 cells was observed. Magnetic resonance imaging (MRI) indicated a high level of accumulation of the nano-magnets within the tumor site. In conclusion Epi-Apt-SPION tertiary complex is introduced as an effective system for targeted delivery of Epi to C26 cells. Moreover this complex could efficiently detect tumors when analyzed by MRI and inhibit tumor growth in vivo.

Targeted delivery of Epirubicin to cancer cells by PEGylated A10 aptamer

Clinical administrations of anthracyclines are limited by cardiotoxicity and myelosuppression. Targeted delivery of anticancer agents is especially important in reducing their side effects. In this work, A10 (Apt), an aptamer for prostate-specific membrane anytigen (PSMA), was applied for targeted delivery of Epirubicin (Epi) to LNCaP cells (PSMA(+)). Flow cytometry analysis showed that PEG-Apt-Epi complex was internalized effectively to LNCaP cells (PSMA(+)), but not to PC3 cells (PSMA(-)). This fact was confirmed by less cytotoxicity of PEG-Apt-Epi complex in PC3 cells in comparison with Epi alone. No significant change in viability between Epi- and complex-treated LNCaP cells was observed. In conclusion, PEG-Apt-Epi complex is an efficient and simple system for specific delivery of drug to PSMA-expressing cell lines.

Proteomic analysis of rat cerebral cortex following subchronic acrolein toxicity

Acrolein, a member of reactive α,β-unsaturated aldehydes, is a major environmental pollutant. Acrolein is also produced endogenously as a toxic by-product of lipid peroxidation. Because of high reactivity, acrolein may mediate oxidative damages to cells and tissues. It has been shown to be involved in a wide variety of pathological states including pulmonary, atherosclerosis and neurodegenerative diseases. In this study we employed proteomics approach to investigate the effects of subchronic oral exposures to 3mg/kg of acrolein on protein expression profile in the brain of rats. Moreover effects of acrolein on malondialdehyde (MDA) levels and reduced glutathione (GSH) content were investigated. Our results revealed that treatment with acrolein changed levels of several proteins in diverse physiological process including energy metabolism, cell communication and transport, response to stimulus and metabolic process. Interestingly, several differentially over-expressed proteins, including β-synuclein, enolase and calcineurin, are known to be associated with human neurodegenerative diseases. Changes in the levels of some proteins were confirmed by Western blot. Moreover, acrolein increases the level of MDA, as a lipid peroxidation biomarker and decreased GSH concentrations, as a non-enzyme antioxidant in the brain of acrolein treated rats. These findings suggested that acrolein induces the oxidative stress and lipid peroxidation in the brain, and so that may contribute to the pathophysiology of neurological disorders.

Affinity-based target deconvolution of safranal

Background and the purpose of the study

Affinity-based target deconvolution is an emerging method for the identification of interactions between drugs/drug candidates and cellular proteins, and helps to predict potential activities and side effects of a given compound. In the present study, we hypothesized that a part of safranal pharmacological effects, one of the major constituent of Crocus sativus L., relies on its physical interaction with target proteins.

Methods

Affinity chromatography solid support was prepared by covalent attachment of safranal to agarose beads. After passing tissue lysate through the column, safranal-bound proteins were isolated and separated on SDS-PAGE or two-dimensional gel electrophoresis. Proteins were identified using MALDI-TOF/TOF mass spectrometry and Mascot software.

Results and major conclusion

Data showed that safranal physically binds to beta actin, cytochrome b-c1 complex sub-unit 1, trifunctional enzyme sub-unit beta and ATP synthase sub-unit alpha and beta. These interactions may explain part of safranal’s pharmacological effects. However, phenotypic and/or biological relevance of these interactions remains to be elucidated by future pharmacological studies.

Evaluation of diazinon-induced hepatotoxicity and protective effects of crocin

Diazinon (DZN) is one of the most widely used insecticides in agricultural pest control. Previous studies have shown that DZN may induce hepatotoxicity. Reactive oxygen species and apoptosis pathways are involved in the toxicity of DZN. Crocin, a constituent of saffron, has hepatoprotective effects due to its antioxidant activity. In this study, we examined the effects of subacute DZN exposure and ameliorating effect of crocin on lipid peroxidation and pathological changes in rat liver. Moreover, protein levels of activated and total caspases-3 and -9 and Bax/Bcl-2 ratio were measured. Five groups of rats were used in the experiment. Corn oil (control), DZN (15 mg/kg per day, orally) and crocin (12.5, 25 and 50 mg/kg per day, intraperitoneally in combination with DZN) were given to male Wistar rats ( n = 6) for 4 weeks. The level of malondialdehyde (MDA) increased significantly in DZN group compared with the control group ( p < 0.05). MDA level decreased significantly in the group that received DZN plus 25 mg crocin ( p < 0.001). No gross or histological evidence of treatment-related damage to the liver after oral exposure to DZN was observed. DZN also induced apoptosis through activation of caspases-9 and -3 and increasing Bax/Bcl-2 ratio. Crocin attenuated the activation of caspases and reduced the Bax/Bcl-2 ratio. It is concluded that subacute exposure to DZN induces oxidative stress-mediated apoptosis and crocin may reduce DZN-induced hepatotoxicity.

Crocin restores hypotensive effect of subchronic administration of diazinon in rats

OBJECTIVE(S)

In this study, the effects of crocin against subchronic toxicity of diazinon (DZN) on systolic blood pressure (SBP) and heart rate (HR) were evaluated in rats.

MATERIALS AND METHODS

Rats were equally divided into 7 groups; control (corn oil), DZN (15 mg/kg), crocin (each group received 12.5, 25 or 50 mg/kg crocin plus DZN), vitamin E (200 IU/kg plus DZN) and crocin (50 mg/kg) treated groups. Rats were given DZN via gavage once a day for 4 weeks. Vitamin E (three times per week) and crocin (once a day) were intraperitoneally injected to rats for 4 weeks. Plasma cholinesterase activity (Elman method), malondealdehyde (MDA) levels in the aortic tissue (Thiobarbituric acid reactive substances or TBARS method); SBP and HR (tail cuff method) were evaluated at the end of 4th week.

RESULTS

A significant decrease in cholinesterase activity was observed in DZN group (P< 0.001). Crocin did not show any effects on cholinesterase activity. DZN increased MDA levels in aortic tissue (P< 0.001) in comparison with control group. Crocin and vitamin E plus DZN decreased MDA elevation induced by DZN in aortic tissue. DZN significantly reduced SBP (P< 0.01) and increased HR (P< 0.001) in comparison with control. Concurrent administration of crocin and DZN, improved the reduction of SBP and the elevation of HR induced by DZN in rat. Crocin alone did not have any effect on SBP and HR.

CONCLUSION

This study showed that concurrent administration of crocin and DZN could restore the effects of subchronic DZN administration on SBP and HR in rats.

Reversible targeting and controlled release delivery of daunorubicin to cancer cells by aptamer-wrapped carbon nanotubes

AIM

Single-walled carbon nanotubes (SWNTs) have been already used as drug carriers. In this study, we introduced sgc8c aptamer (this aptamer targets leukemia biomarker protein tyrosine kinase-7) to complex between Dau (daunorubicin) and SWNT to enhance targeted delivery of Dau to acute lymphoblastic leukemia T-cells (Molt-4).

MATERIAL AND METHODS

Dau-aptamer-SWNTs tertiary complex formation was analyzed by visible spectroscopy and spectrofluorophotometric analysis. Dau release profiles from the complex were investigated in pH 7.4 and 5.5. For cytotoxic studies (MTT assay), Molt-4 (target) and U266 (B lymphocyte human myeloma, non-target) cells were treated with Dau, Dau-aptamer-SWNTs tertiary complex. Internalization was analyzed by flow cytometry. Targeted delivery of Dau was antagonized using antisense of aptamer.

RESULTS

Dau was efficiently loaded onto SWNTs (efficiency ∼ 157%). Dau was released from Dau-aptamer-SWNTs tertiary complex in a pH-dependent manner (higher release rate at pH 5.5). Flow cytometric analysis showed that the tertiary complex was internalized effectively to Molt-4 cells, but not to U266 cells. Cytotoxicity of Dau-aptamer-SWNTs tertiary complex also confirmed internalization data. Dau-aptamer-SWNTs tertiary complex was less cytotoxic in U266 cells when compared to Dau alone. No significant change in viability between Dau- and complex-treated Molt-4 cells was observed. Cytotoxicity of Dau-aptamer-SWNTs complex was efficiently and quickly reversed using antisense in Molt-4 cells.

CONCLUSION

Dau-aptamer-SWNTs complex is able to selectively target Molt-4 cells. The other advantages of this system are reversibility and pH-dependent release of Dau from its complex.

Targeted delivery of daunorubicin to T-cell acute lymphoblastic leukemia by aptamer

Application of daunorubicin in treatment of leukemia has been limited for its side effects like cardiotoxicity. Specific delivery of chemotherapy drugs is an important factor in decreasing their side effects. In this study, sgc8, an aptamer for protein tyrosine kinase-7 (PTK7), was used for specific delivery of daunorubicin to Molt-4 cells (PTK7(+)). Flow cytometric experiments showed that aptamer-daunorubicin complex was internalized effectively to Molt-4 cells (PTK7(+)), but not to U266 cells (PTK7(-)). This fact was confirmed by less cytotoxicity of aptamer-drug complex in U266 cells in compare to daunorubicin alone. No significant change in viability between daunorubicin and aptamer-daunorubicin complex treated Molt4 cells was observed. In conclusion, sgc8-daunorubicin complex is introduced as a simple and efficient system for targeted delivery of drug to acute lymphoblastic leukemia T cells.

Diets enriched in oat bran or wheat bran temporally and differentially alter the composition of the fecal community of rats

A clear understanding of how diet alters gastrointestinal communities is important given the suggested link between gut community composition and a wide variety of disease pathologies. To characterize this link for commonly consumed dietary fiber sources, we investigated the change in the fecal community of rats fed diets containing 5% nonnutritive fiber (control), 3% (wt:wt) oat bran plus 2% nonnutritive fiber (OB), or 5% (w/w) wheat bran (WB) over a 28-d feeding trial using both molecular- and cultivation-based methodologies. Pooled fecal samples from 8 rats fed the same diet were analyzed at 4 time points. On d 28, bran-fed rats had approximately twice the total cultivable bacteria than rats fed the control diet. Over the course of feeding, the cultivable community was initially dominated by bacteroides, then by bifidobacteria, lactobacilli, enterococci, and various enterics. In contrast, molecular analysis revealed the appearance of new operational taxonomic units (phylotypes) that were both temporally and inequitably distributed throughout the fecal community. The majority of change occurred in 2 major lineages within the Firmicutes: the Clostridium coccoides group and the Clostridium leptum subgroup. The time course of change depended on the source of bran, with the majority of new phylotypes appearing by d 14 (OB) or d 28 (WB), although adaptation of the fecal community was slow and continued over the entire feeding trial. Bacterial community richness was higher in bran-fed rats than in those fed the control diet. Change within the C. coccoides and C. leptum lineages likely reflect their high abundance within the gut bacterial community and the role of clostridia in fiber digestion. The results illustrate the limitations of relying solely on cultivation to assess bacterial changes and illustrate that community changes are complex in an ecosystem containing high numbers of interdependent and competing species of bacteria.

Skeletal muscle hexokinase: regulation in mammalian hibernation

Skeletal muscle hexokinase (HK) from Richardson's ground squirrels was analyzed to determine how the enzyme is regulated during hibernation, a state of cold torpor. The HK II isozyme dominated in muscle and ~15% of total HK was bound to the insoluble fraction. HK maximum activity was 33% lower in hibernator muscle and the enzyme showed a significantly higher K ( m ) ATP (by 80%) and a lower K ( i ) for glucose-6-P (by 40%) than euthermic HK (assayed at 22 degrees C). However, 5 degrees C assay significantly reduced K ( m ) glucose of hibernator HK. Stimulation of AMP-dependent protein kinase (AMPK) in hibernator extracts elevated the HK activity and reduced K ( m ) ATP, but did not affect euthermic HK. Stimulation of protein phosphatases significantly lowered the HK activity in both situations. AMPK-dependent phosphorylation was confirmed by immunopreciptiation of (32)P-labeled HK. DEAE-Sephadex ion exchange chromatography revealed two peaks of HK in hibernator muscle extracts (low and high phosphate forms), whereas only a single peak of phospho-HK was present in euthermic muscle. We conclude that differential control of muscle HK in euthermic versus hibernating states is derived from two main regulatory influences, reversible protein phosphorylation and temperature effects on kinetic properties.

Regulation of skeletal muscle creatine kinase from a hibernating mammal

Control over skeletal muscle energetics is critical in hibernation to sustain viability over weeks of cold torpor and to support shivering thermogenesis during arousal. Creatine kinase (CK) has a key role in muscle energetics and this study analyzes muscle CK from ground squirrels, Spermophilus richardsonii. CK activity was approximately 20% lower during hibernation than in euthermia, as was CK protein whereas CK mRNA was reduced by approximately 70%. Hibernator CK showed reduced affinity for ATP and creatine, compared with euthermic CK. Incubations that promoted endogenous protein kinase or phosphatase action, coupled with ion exchange chromatography to separate high and low phosphate forms, showed that soluble CK from euthermic squirrels was a mix of phosphorylated and dephosphorylated forms whereas only phospho-CK was detected in hibernating animals. High and low phosphate CK forms had different affinities for ATP and creatine substrates but did not differ in stability to urea denaturation. About 20-25% of CK was bound to the insoluble fraction of muscle and bound CK showed different kinetic responses to kinase and phosphatase treatments.