CARP-1 Functional Mimetics: A Novel Class of Small Molecule Inhibitors of Medulloblastoma Cell Growth

Medulloblastomas (MBs) constitute an aggressive class of intracranial pediatric tumors. Current multimodality treatments for MBs include surgery, ionizing radiation, and chemotherapy. Toxic side effects of therapies coupled with high incidence of recurrence and the metastatic spread warrant development of more effective, less toxic therapies for this disease. CARP-1/CCAR1 is a peri-nuclear phospho-protein that is a co-activator of the cell cycle regulatory anaphase promoting complex/cyclosome (APC/C) E3 ligase. CARP-1 functional mimetics (CFMs) are a novel class of small molecule compounds that interfere with CARP-1 binding with APC/C subunit APC-2, and suppress growth of a variety of cancer cells in part by promoting apoptosis. Here we investigated MB growth inhibitory potential of the CFMs and found that CFM-4 inhibits growth of MB cells in part by inducing CARP-1 expression, promoting PARP cleavage, activating pro-apoptotic stress-activated protein kinases (SAPK) p38 and JNK, and apoptosis. Gene-array-based analysis of the CFM-4-treated Daoy MB cells indicated down-regulation of a number of key cell growth and metastasis-promoting genes including cell motility regulating small GTP binding protein p21Rac1, and extracellular matrix metallopeptidase (MMP)-10. Moreover, CFM-4 treatment stimulated expression of a number of molecules such as neurotrophin (NTF)3, and NF-κB signaling inhibitors ABIN1 and 2 proteins. Overexpression of NTF3 resulted in reduced MB cell viability while knock-down of NTF3 interfered with CFM-4-dependent loss of viability. CFMs also attenuated biological properties of the MB cells by blocking their abilities to migrate, form colonies in suspension, and invade through the matrix-coated membranes. Together our data support anti-MB properties of CFM-4, and provide a proof-of-concept basis for further development of CFMs as potential anti-cancer agents for MBs.     

Alpha-lipoic acid rebalances redox and immune-testicular milieu in septic rats

In the present study, lipopolysaccharide (LPS), as an immune modulator in male adult rats and alpha-lipoic acid (ALA), as a powerful biological antioxidant and anti-inflammatory, are examined to help understanding the role of the immune and redox perturbation in testicular dysfunction with a possible protection. A total of 60 male Swiss albino rats were divided into 5 groups (10/group) respectively as follows Saline, ALA-vehicle, ALA (200 mg/kg), LPS (5 mg/kg) started with 20 rats and LPS + ALA. Obtained data from previously reported study, in our laboratory, and from the present one revealed that LPS induced marked reductions in sperm's count, motility and resulted in deterioration of the testicular histological features. In addition, LPS decreased testicular reduced glutathione (GSH) level and lactate dehydrogenase isoenzyme-x (LDH-x) activity. However, it increased testicular levels of malondialdehyde (MDA), nitric oxide (NO) and 8-hydroxydeoxyguanosine (8-HDG) in testicular DNA, along with increased serum IL-2 level. In contrast, rats pretreated with ALA showed almost complete normalization of all the tested parameters. In conclusion, LPS induced perturbation of the immune-testicular barrier as a result of redox imbalance with a subsequent testicular dysfunction. Pretreatment with ALA ameliorated all these effects by its immune-modulator and antioxidant mechanisms suggesting a protective role against male infertility in septic or severely infected patients.     

Thymoquinone suppression of the human hepatocellular carcinoma cell growth involves inhibition of IL-8 expression,elevated levels of TRAIL receptors,oxidative stress and apoptosis

Sod2 is the major salt tolerance plasma membrane protein of Schizosaccharomyces pombe. It functions to remove excess intracellular sodium (or lithium) in exchange for protons. We investigated the role of cysteine residues and created a cysteine-free Sod2 protein. Each cysteine residue of the ten present was individually mutated to serine and the different proteins expressed and characterized in S. pombe. Western blotting revealed that all the individual mutant proteins were expressed. We examined the ability of the mutant proteins to confer salt tolerance to S. pombe with the endogenous Sod2 protein deleted. Only proteins with C26S and C374S mutations were partially reduced in their ability to confer salt tolerance. Additionally, they showed a change in conformation in comparison to the wild-type protein, indicated by differential sensitivity to trypsin. Deletion of all the cysteine residues of Sod2 resulted in a functional protein that was expressed in S. pombe at levels similar to the wild type and also conferred salt tolerance. The conformation of the cysteine-free Sod2 protein was not altered relative to the wild-type protein. We examined the accessibility of amino acids of the cysteineless protein present on putative extracellular loop 2. A cysteine placed at position Ala119 was accessible to externally applied [2-(trimethylammonium)ethyl] methane thiosulfonate bromide. The results demonstrate that cysteines in the Sod2 protein can be changed to serine residues resulting in an expressed, functional protein. The utility of the cysteine-free Sod2 protein for determination of topology and amino acid accessibility is demonstrated.     

Prevalence and identification of Anisakis nematodes in fish consumed in Marrakesh,Morocco

Molecular Biology Reports - Morocco is considered as an important producer of fish with more than one million tons of small pelagic fish caught per year, along more than 3400 km of...     

Metabolic interactions between hyperhomocysteinemia and endothelin-1 among Tunisian patients with acute coronary diseases

Background

Acute coronary syndromes (ACS) are complex and polygenic diseases which are a real problem of public health. These syndromes require multidisciplinary studies to understand the pathogenesis mechanisms and metabolic interactions between different risk factors.This study aimed to explore the variation of two coronary risk parameters not mentioned by Framingham cohorts, hyperhomocysteinemia and endothelin-1 (ET-1) in Tunisian coronary and the study of the variation of these parameters based on various cardiac risk factors and metabolic relationship between them.To 157 coronary and 142 healthy subjects, the concentration of homocysteine was quantified by fluorescence polarization immunoassay; the concentration of ET-1 was measured by an analytical technique, the High Performance Liquid Chromatography (HPLC) coupled with mass spectrometry.

Results

Our study showed that homocysteine and ET-1 were significantly higher in patients compared to healthy subjects (24.40 ± 12.5 μmol/L vs 7.44 ± 2.5 μmol/L p <0.00001) for homocysteine and (15.2 ± 5.3 nmol/L vs 7.1 ± 2.7 nmol/L, p <0.00001) for ET-1. On the other hand, homocysteine varies according to tobacco and diabetes while ET-1 depends on the sex, hypertension, smoking, obesity and dyslipidemia and a statistically negative correlation was shown between homocysteine and ET-1 in coronary patients (r = −0.66 p <0.00001).

Conclusion

The study of the variation of these two parameters in coronary patients and metabolic exploration of the relationship between homocysteine and ET-1 according to various risk factors and the interactions between themselves facilitates the decision of therapeutic treatment.     

Detection and Molecular Characterization of Cryptosporidium spp. from Wild Rodents and Insectivores in South Korea

In order to examine the prevalence of Cryptosporidium infection in wild rodents and insectivores of South Korea and to assess their potential role as a source of human cryptosporidiosis, a total of 199 wild rodents and insectivore specimens were collected from 10 regions of South Korea and screened for Cryptosporidium infection over a period of 2 years (2012-2013). A nested-PCR amplification of Cryptosporidium oocyst wall protein (COWP) gene fragment revealed an overall prevalence of 34.2% (68/199). The sequence analysis of 18S rRNA gene locus of Cryptosporidium was performed from the fecal and cecum samples that tested positive by COWP amplification PCR. As a result, we identified 4 species/genotypes; chipmunk genotype I, cervine genotype I, C. muris, and a new genotype which is closely related to the bear genotype. The new genotype isolated from 12 Apodemus agrarius and 2 Apodemus chejuensis was not previously identified as known species or genotype, and therefore, it is supposed to be a novel genotype. In addition, the host spectrum of Cryptosporidium was extended to A. agrarius and Crosidura lasiura, which had not been reported before. In this study, we found that the Korean wild rodents and insectivores were infected with various Cryptosporidium spp. with large intra-genotypic variationa, indicating that they may function as potential reservoirs transmitting zoonotic Cryptosporidium to livestock and humans.     

Liver X receptors, lipids and their reproductive secrets in the male

Liver X receptor (LXR) α and LXRβ belong to the nuclear receptor superfamily. For many years, they have been called orphan receptors, as no natural ligand was identified. In the last decade, the LXR natural ligands have been shown to be oxysterols, molecules derived from cholesterol. While these nuclear receptors have been abundantly studied for their roles in the regulation of lipid metabolism, it appears that they also present crucial activities in reproductive organs such as testis and epididymis, as well as prostate. Phenotypic analyses of mice lacking LXRs (lxr−/−) pointed out their physiological activities in the various cells and organs regulating reproductive functions. This review summarizes the impact of LXR-deficiency in male reproduction, highlighting the novel information coming from the phenotypic analyses of lxrα−/−, lxrβ−/− and lxrα;β−/− mice. This article is part of a Special Issue entitled: Translating nuclear receptor from health to disease.