Screening of amide analogues of Trichostatin A in cultures of primary rat hepatocytes: search for potent and safe HDAC inhibitors

Summary  The vast majority of preclinical studies of HDAC inhibitors (HDAC-I) focus on the drug–target (cancer) cell interaction, whereas little attention is paid to the effects on non-target healthy cells, which could provide decisive information to eliminate potential cytotoxic compounds at a very early stage during drug development. In the current study we used cultures of primary rat hepatocytes as a read out system to select for the most potent HDAC-I in the group of structural analogues of an archetypal HDAC-I, namely Trichostatin A. This kind of approach allowed selecting compounds with high biological activity and with no apparent toxicity towards cultured hepatocytes. Joanna Fraczek and Sarah Deleu contributed equally to this article. T. Vanhaecke is a postdoctoral research fellow of the Fund for Scientific Research Flanders (FWO-Vlaanderen, Belgium)     

Ile<Superscript>105</Superscript>Val <Emphasis Type="Italic">GSTP1</Emphasis> polymorphism and susceptibility to colorectal carcinoma in Bulgarian population

Background and aims Etiologically, the sporadic colorectal cancer (CRC) is a complex and multifactorial disease that is linked to both exogenic and endogenic factors. Accumulating evidence indicates that susceptibility to cancers, including CRC, is mediated by genetically determined differences in the effectiveness of detoxification of potential carcinogens. A member of the glutathione-S-transferase (GST) family, GSTP1, is an important candidate for involvement in susceptibility to carcinogen-associated CRC. An A→G transition in exon 5 of the GSTP1 gene resulting in Ile¹⁰⁵Val amino acid substitution has been identified. This change leads to alteration in catalytic efficiency of variant enzyme. The aim of the current study was to evaluate the influence of Ile¹⁰⁵Val GSTP1 polymorphism on susceptibility to CRC. Materials and methods The GSTP1 genotyping was conducted in a case-control study of 80 ethnic Bulgarian CRC patients and 126 unaffected controls using polymerase chain reaction restriction fragment length polymorphism method. Results A statistically significant case-control difference in genotype frequencies was observed: 0.69 vs 0.54 for Ile/Ile, 0.22 vs 0.39 for Ile/Val, and 0.09 vs 0.07 for Val/Val (p = 0.049). The odds ratio (OR) for Val/Val was close to 1 (0.96, 95%CI: 0.35–2.66, p = 0.942), whereas the OR for Ile/Val was significantly lower, 0.45 (95%CI: 0.24–0.86, p = 0.016), compared to the referent Ile/Ile genotype. Although a prevalence of the GSTP1 variant allele-containing genotypes (Ile/Val or Val/Val) was found in controls than in patients (OR = 0.53, 95%CI: 0.30–0.96, p = 0.035), the allele frequencies did not show significant difference between cases and controls (p = 0.127). Conclusions Based on the obtained protective effect of Ile/Val GSTP1 genotype, we could suggest that Ile¹⁰⁵Val GSTP1 polymorphism may play some role in susceptibility to CRC.     

Protection against mouse and avian influenza A strains via vaccination with a combination of conserved proteins NP, M1 and NS1

Background Experimental data accumulated over more than a decade indicate that cross‐strain protection against influenza may be achieved by immunization with conserved influenza proteins. At the same time, the efficacy of immunization schemes designed along these lines and involving internal influenza proteins, mostly NP and M1, has not been sufficient. Objective To test the immunogenicity and protective efficacy of DNA vaccination with a combination of NP, M1 and NS1 genes of influenza virus. Methods The immunogenicity and protective efficacy of DNA vaccination with NP, M1 and NS1 was tested in mice and chickens. Mice were challenged with mouse‐adapted viral strains H3N2 and H5N2 and chicken challenged with avian H5N3 virus. Results In these settings, wild‐type NS1 did not impede the cellular and humoral response to NP/M1 immunization in vivo. Moreover, addition of NS1‐encoding plasmid to the NP/M1 immunization protocol resulted in a significantly increased protective efficacy in vivo. Conclusions The addition of NS1 to an influenza immunization regimen based on conserved proteins bears promise. It is feasible that upon further genetic modification of these and additional conserved influenza proteins, providing for their higher safety, expression and immunogenicity, a recombinant vaccine based on several structural and non‐structural proteins or their epitopes will offer broad anti‐influenza protection in a wide range of species.     

Structural insights into eRF3 and stop codon recognition by eRF1

Eukaryotic translation termination is mediated by two interacting release factors, eRF1 and eRF3, which act cooperatively to ensure efficient stop codon recognition and fast polypeptide release. The crystal structures of human and Schizosaccharomyces pombe full-length eRF1 in complex with eRF3 lacking the GTPase domain revealed details of the interaction between these two factors and marked conformational changes in eRF1 that occur upon binding to eRF3, leading eRF1 to resemble a tRNA molecule. Small-angle X-ray scattering analysis of the eRF1/eRF3/GTP complex suggested that eRF1''s M domain contacts eRF3''s GTPase domain. Consistently, mutation of Arg192, which is predicted to come in close contact with the switch regions of eRF3, revealed its important role for eRF1''s stimulatory effect on eRF3''s GTPase activity. An ATP molecule used as a crystallization additive was bound in eRF1''s putative decoding area. Mutational analysis of the ATP-binding site shed light on the mechanism of stop codon recognition by eRF1.     

Performance of the Genotype? MTBDRPlus assay in the diagnosis of tuberculosis and drug resistance in Samara, Russian Federation

Background  

Russia is a high tuberculosis (TB) burden country with a high prevalence of multidrug resistant tuberculosis (MDRTB). Molecular assays for detection of MDRTB on clinical specimens are not widely available in Russia.     

Intracerebroventricular infusion of acid sphingomyelinase corrects CNS manifestations in a mouse model of Niemann–Pick A disease

Niemann–Pick A (NPA) disease is a lysosomal storage disorder (LSD) caused by a deficiency in acid sphingomyelinase (ASM) activity. Previously, we showed that the storage pathology in the ASM knockout (ASMKO) mouse brain could be corrected by intracerebral injections of cell, gene and protein based therapies. However, except for instances where distal areas were targeted with viral vectors, correction of lysosomal storage pathology was typically limited to a region within a few millimeters from the injection site. As NPA is a global neurometabolic disease, the development of delivery strategies that maximize the distribution of the enzyme throughout the CNS is likely necessary to arrest or delay progression of the disease. To address this challenge, we evaluated the effectiveness of intracerebroventricular (ICV) delivery of recombinant human ASM into ASMKO mice. Our findings showed that ICV delivery of the enzyme led to widespread distribution of the hydrolase throughout the CNS. Moreover, a significant reduction in lysosomal accumulation of sphingomyelin was observed throughout the brain and also within the spinal cord and viscera. Importantly, we demonstrated that repeated ICV infusions of ASM were effective at improving the disease phenotype in the ASMKO mouse as indicated by a partial alleviation of the motor abnormalities. These findings support the continued exploration of ICV delivery of recombinant lysosomal enzymes as a therapeutic modality for LSDs such as NPA that manifests substrate accumulation within the CNS.     

Application of automated quantitative cytometry in diagnosis of lung cancer

The paper deals with evaluation of the literature data and our experience with automated quantitative cytometric examination of sputum for diagnosis of lung cancer and, in particular, early one. This novel procedure uses measurement of quantitative indices which characterise tumors-induced alterations. The LungSign computerized system was employed to scan cellular nuclei. The results were evaluated by linear discriminative analysis with the aid of ROC-curves and underlying areas. The procedures were run in 248 cases and its sensitivity was significantly higher that of a standard cytological one (36.6% and 13.3%, respectively; p = 0.033), albeit a slight decrease in specificity (93.7% and 100%, respectively; p = 0.003). Automated quantitative cytometric indices varied significantly in cohorts of patients with confirmed (-0.275871) and false (-1.24990) diagnosis of lung cancer (p = 0.0001).     

Increased gene expression levels of collagen receptor integrins are associated with decreased survival parameters in patients with advanced melanoma

Expression of collagen receptor integrins alpha1beta1 and alpha2beta1 has been associated with progression and metastatic potential of malignant melanoma. Integrin alpha2beta1 was originally characterized as a melanoma progression antigen. We have used real-time quantitative PCR to study the mRNA expression levels of three collagen receptor integrin chains, that is alpha1, alpha2 and alpha11 in metastases from 26 patients with melanoma. Interestingly, we find that survival after initiation of chemoimmunotherapy was significantly decreased in all patients whose tumours expressed high mRNA levels of alpha1 integrin, alpha2 integrin or alpha11 integrin when compared with lower tumour expression levels (P<0.05, log rank test). Moreover, those patients with high mRNA levels of all studied integrins had a significantly shorter survival from the appearance of the first metastasis than the patients with low levels of integrins (P<0.05). Furthermore, a high mRNA expression level of integrin alpha2 was found to be associated with poorer overall survival. High alpha2 mRNA levels (n=6) were associated with median survival of 35 months and low alpha2 mRNA levels (n=20), with median survival of 53 months (P=0.033). We conclude that collagen receptor integrins are important in the progression and prognosis of metastatic melanoma, and their measurements might be used as predictive markers when assessing disease progression.     

Identification and characterization of mutations conferring resistance to an HCV RNA-dependent RNA polymerase inhibitor in vitro

Compound A-837093, a non-nucleoside HCV RNA-dependent RNA polymerase inhibitor, displayed nanomolar potencies against HCV genotypes 1a and 1b replicons. It also exhibited an excellent metabolic profile and achieved high plasma and liver concentrations in animals. In order to characterize the development of resistance to this anti-HCV agent, HCV subgenomic 1b strain N replicon cells were cultured in the presence of A-837093 with G418. Mutations S368A, Y448H, G554D, Y555C, and D559G in the NS5B polymerase gene were identified that led to substantial decreases in the susceptibilities of 1b genotype replicons to the inhibitor A-837093. However, the resistant mutants remained susceptible to HCV protease inhibitor BILN-2061 and alpha interferon as well as to a different class of non-nucleoside HCV polymerase inhibitor. In addition, each single resistant mutation identified significantly reduced the replication capacity of mutant compared to wild-type replicon. These findings provide a strategic guide for the future development of non-nucleoside inhibitors of HCV NS5B polymerase.