Smac mimetics as novel promising modulators of apoptosis in the treatment of breast cancer

Breast cancer is the most prevalent cancer in women. Despite improvements in treatment, the rate of breast cancer-related deaths is still high, and this issue needs further, accurate investigations. Although several treatment options are available, none of them are efficient for complete remission, particularly in advanced stages of the disease. It is known that cancerous cells have dysregulated apoptosis-related pathways, by which they can remain alive for a long time, expand freely, and escape from apoptosis-inducing drugs or antitumor immune responses. Therefore, modulation of apoptosis resistance in cancer cells may be an efficient strategy to overcome current problems faced in the development of immunotherapeutic approaches for the treatment of breast cancer. The inhibitors of apoptosis protein (IAPs) are important targets for cancer therapy because it has been shown that these molecules are overexpressed and highly active in various cancer cells and suppress apoptosis process in malignant cells by blockage of caspase proteins. There is evidence of Smac mimetics efficacy as a single agent; however, recent studies have indicated the efficacy of current anticancer immunotherapeutic approaches when combined with Smac mimetics, which are potent inhibitors of IAPs and synthesized mimicking Smac/Diablo molecules. In this review, we are going to discuss the efficacy of treatment of breast cancer by Smac mimetics alone or in combination with other therapeutics.     

Investigations on the interactions of DiAmsar with serum albumins: Insights from spectroscopic and molecular docking techniques

Diamine‐sarcophagine (DiAmsar) binding to human serum albumin (HSA) and bovine serum albumin (BSA) was investigated under simulative physiological conditions. Fluorescence spectra in combination with Fourier transform infrared (FT‐IR), UV‐visible (UV–vis) spectroscopy, cyclic voltammetry (CV), and molecular docking method were used in the present work. Experimental results revealed that DiAmsar had an ability to quench the HSA and BSA intrinsic fluorescence through a static quenching mechanism. The Stern–Volmer quenching rate constant (K_sv) was calculated as 0.372 × 10³ M^‐1 and 0.640 × 10³ M^‐1 for HSA and BSA, respectively. Moreover, binding constants (K_a), number of binding sites (n) at different temperatures, binding distance (r), and thermodynamic parameters (?H°, ?S°, and ?G°) between DiAmsar and HSA (or BSA) were calculated. DiAmsar exhibited good binding propensity to HSA and BSA with relatively high binding constant values. The positive ?H° and ?S° values indicated that the hydrophobic interaction is main force in the binding of the DiAmsar to HSA (or BSA). Furthermore, molecular docking results revealed the possible binding site and the microenvironment around the bond. Copyright © 2014 John Wiley & Sons, Ltd.     

Kinetic, thermodynamic and statistical studies on the inhibition of adenosine deaminase by aspirin and diclofenac

The kinetic and thermodynamic effects of aspirin and diclofenac on the activity of adenosine deaminase (ADA) were studied in 50 mM phosphate buffer pH = 7.5 at 27 and 37 degrees C, using UV-Vis spectrophotometry and isothermal titration calorimetry (ITC). Aspirin exhibits competitive inhibition at 27 and 37 degrees C and the inhibition constants are 42.8 and 96.8 microM respectively, using spectrophotometry. Diclofenac shows competitive behavior at 27 degrees C and uncompetitive at 37 degrees C with inhibition constants of 56.4 and 30.0 microM, at respectively. The binding constant and enthalpy of binding, at 27 degrees C are 45 microM, - 64.5 kJ/mol and 61 microM, - 34.5 kJ/mol for aspirin and diclofenac. Thermodynamic data revealed that the binding process for these ADA inhibitors is enthalpy driven. QSAR studies by principal component analysis implemented in SPSS show that the large, polar, planar, and aromatic nucleoside and small, aromatic and polar non-nucleoside molecules have lower inhibition constants.     

Proteomics uncovers a role for redox in drought tolerance in wheat

Proteomic analysis offers a new approach to identify a broad spectrum of genes that are expressed in living systems. We applied a proteomic approach to study changes in wheat grain in response to drought, a major environmental parameter adversely affecting development and crop yield. Three wheat genotypes differing in genetic background were cultivated in field under well-watered and drought conditions by following a randomized complete block design with four replications. The overall effect of drought was highly significant as determined by grain yield and total dry matter. About 650 spots were reproducibly detected and analyzed on 2-DE gels. Of these, 121 proteins showed significant change under drought condition in at least one of the genotypes. Mass spectrometry analysis using MALDI-TOF/TOF led to the identification of 57 proteins. Two-thirds of identified proteins were thioredoxin (Trx) targets, in accordance with the link between drought and oxidative stress. Further, because of contrasting changes in the tolerant and susceptible genotypes studied, several proteins emerge as key participants in the drought response. In addition to providing new information on the response to water deprivation, the present study offers opportunities to pursue the breeding of wheat with enhanced drought tolerance using identified candidate genetic markers. The 2-DE database of wheat seed proteins is available for public access at http://www.proteome.ir.     

A cold-adapted endoglucanase from camel rumen with high catalytic activity at moderate and low temperatures: an anomaly of truly cold-adapted evolution in a mesophilic environment

Endoglucanases are important enzymes in plant biomass degradation. They have current and potential applications in various industrial sectors including human and animal food processing, textile, paper, and renewable biofuel production. It is assumed that the cold-active endoglucanases, with high catalytic rates in moderate and cold temperatures, can improve the cost-effectiveness of industrial processes by lowering the need for heating and, thus, energy consumption. In this study, the endoglucanase CelCM3 was procured from a camel rumen metagenome via gene cloning and expression in Escherichia coli BL21 (DE3). The maximum activity of the enzyme on carboxymethyl cellulose (CMC) was obtained at pH 5 and 30 °C with a V_max and K_m of 339 U/mg and 2.57 mg/ml, respectively. The enzyme with an estimated low melting temperature of 45 °C and about 50% activity at 4 °C was identified to be cold-adapted. A thermodynamic analysis corroborated that CelCM3 with an activation energy (E_a), enthalpy of activation (ΔH), and Gibb’s free energy (ΔG) of, respectively, 18.47 kJ mol⁻¹, 16.12 kJ mol⁻¹, and 56.09 kJ mol⁻¹ is a cold-active endoglucanase. In addition, CelCM3 was tolerant of metal ions, non-ionic detergents, urea, and organic solvents. Given these interesting characteristics, CelCM3 shows promise to meet the requirements of industrial applications.

     

Bone marrow–mesenchymal stromal cell infusion in patients with chronic kidney disease: A safety study with 18 months of follow-up

Background

Chronic kidney disease (CKD) is a progressive loss of kidney function and structure that affects approximately 13% of the population worldwide. A recent meta-analysis revealed that cell-based therapies improve impaired renal function and structure in preclinical models of CKD. We assessed the safety and tolerability of bone marrow–mesenchymal stromal cell (MSC) infusion in patients with CKD.

Relationship between breast arterial calcification on mammography with coronary CT angiography findings

Background

Breast arterial calcification is a frequently benign finding on mammography that usually is not reported. An increasing attention has been formed to determine the association between breast arterial calcification (BAC) and Coronary artery disease. In the current study we have aimed to evaluate the relationship between BAC on mammography with coronary CT angiography findings.

Methods

The case control study was carried out on 60 women; 30 CAD and 30 healthy subjects as control, admitted to Golestan hospital radiology department. The mammography was performed in two views; Craniocaudal (CC) view and mediolateral oblique (MLO) and BAC was graded based on the severity and extent of calcifications. Coronary Arterial Calcification (CAC) were scored by Agatston criteria.

Results

Overly, 36 patients (60%) were positive for BAC. Twenty six out of them (72%) were CAD. There was a positive significant correlation between BAC and CAD. The sensitivity and specificity of BAC for CAD were 69% and 47%, respectively. Moreover, the severe BAC scores were significantly higher in CAD patients than non-CAD.

Conclusion

Our findings in line with several previous studies indicated the positive significant association between BAC and CAD occurrence. While the sensitivity and specificity of BAC in diagnosis of CAD is low, suggested the using of BAC just as a CAD risk factor. The relatively low sample size is the major limitation of the study.

     

Isolation and characterization of the mitochondrial ATP synthase fromChlamydomonas reinhardtii. cDNA sequence and deduced protein sequence of the α subunit

We have isolated the F₀F₁-ATP synthase complex from oligomycin-sensitive mitochondria of the green algaChlamydomonas reinhardtii. A pure and active ATP synthase was obtained by eans of sonication, extraction with dodecyl maltoside and ion exchange and gel permeation chromatography in the presence of glycerol, DTT, ATP and-21. The enzyme consists of 14 subunits as judged by SDS-PAGE. A cDNA clone encoding the ATP synthase subunit has been sequenced. The deduced protein sequence contains a presequence of 45 amino acids which is not present in the mature protein. The mature protein is 58–70% identical to corresponding mitochondrial proteins from other organisms. In contrast to the ATP synthase subunit fromC. reinhardtii (Franzen and Falk, Plant Mol Biol 19 (1992) 771–780), the protein does not have a C-terminal extension. However, the N-terminal domain of the mature protein is 15–18 residues longer than in ATP synthase subunits from other organisms. Southern blot analysis indicates that the protein is encoded by a single-copy gene.Abbreviations DM dodecyl--D-maltoside - OSCP oligomycin sensitivity conferring protein - PMSF phenyl-methylsulfonylfluoride - DTT dithiothreitol - EDTA ethylenediaminotetraacetic disodium salt     

Peculiar properties of the PsaF photosystem I protein from the green alga Chlamydomonas reinhardtii: presequence independent import of the PsaF protein into both chloroplasts and mitochondria

It has previously been shown that presequences of nuclear-encoded chloroplast proteins from the green alga Chlamydomonas reinhardtii contain a region that may form an amphiphilic -helix, a structure characteristic of mitochondrial presequences. We have tested two precursors of chloroplast proteins (the PsaF and PsaK photosystem I subunits) from C. reinhardtii for the ability to be imported into spinach leaf mitochondria in vitro. Both precursors bound to spinach mitochondria. The PsaF protein was converted into a protease-protected form with high efficiency in a membrane potential-dependent manner, indicating that the protein had been imported, whereas the PsaK protein was not protease protected. The protease protection of PsaF was not inhibited by a synthetic peptide derived from the presequence of the N. plumbaginifolia mitochondrial F₁ subunit. Furthermore, if the presequence of PsaF was truncated or deleted by in vitro mutagenesis, the protein was still protease-protected with approximately the same efficiency as the full-length precursor. These results indicate that PsaF can be imported by spinach mitochondria in a presequence-independent manner. However, even in the absence of the presequence, this process was membrane potential-dependent. Interestingly, the presequence-truncated PsaF proteins were also protease-protected upon incubation with C. reinhardtii chloroplasts. Our results indicate that the C. reinhardtii chloroplast PsaF protein has peculiar properties and may be imported not only into chloroplasts but also into higher-plant mitochondria. This finding indicates that additional control mechanisms in the cytosol that are independent of the presequence are required to achieve sorting between chloroplasts and mitochondria in vivo.Abbreviations cTP chloroplast transit peptide - mTP mitochondrial targeting peptide - Rubisco ribulose-1,5-bisphosphate carboxylase/oxygenase - pF₁(1,25) a synthetic peptide derived from the first 25 residues of the Nicotiana plumbaginifolia mitochondrial ATP synthase F₁ subunit - PsaF(2–30) and PsaF(2–61) mutant proteins lacking regions corresponding to residues 2–30 and 2–61 in the PsaF precursor protein, respectively