An update on the molecular pathology of urinary bladder tumors

Urothelial carcinoma is the fourth most common tumors after prostate cancer, lung, and colorectal carcinoma but the second most common urologic malignancy. Urothelial carcinoma composed more than 90% of bladder tumors while squamous cell carcinoma and adenocarcinomas composed 5% and 2% respectively. The intense research involving the different molecular aspects of bladder cancer has provided a great insight into identifying more about molecular profiling and pathways of bladder cancer.In this review, we will highlight the general concepts of the molecular features; profiling and classification as well as the molecular pathways for bladder carcinomas, especially urothelial carcinoma. Also, we will discuss the advances of molecular biomarkers for screening, early diagnosis, surveillance and potential prognosis of urothelial carcinoma of the bladder. Studies showed that accumulation of genetic alterations involving the clonal expansion of altered cells with growth advantages through sequential multi-step pathways results in progression of bladder tumors.The accumulated research data from literature has revealed that the genomic signatures of urothelial carcinoma are required to subclassify bladder cancer into genetically distinct subgroups. These findings could improve the understating of pathogenesis as well as will provide new therapeutic modules e.g. targeted therapy.     

Nonsteroidal estrogen receptor isoform‐selective biphenyls

Estrogen receptor (ER) has been a therapeutic target to treat ER‐positive breast cancer, most notably by agents known as selective estrogen receptor modulators (SERMs). However, resistance and severe adverse effects of known drugs gave impetus to the search for newer agents with better therapeutic profile. ERα and ERβ are two isoforms sharing 56% identity and having different physiological functions and expressions in various tissues. Only two residues differ in the active sites of the two isoforms motivating us to design isoform‐selective ligands. Guided by computational docking and molecular dynamics simulations, we have designed, synthesized, and tested, substituted biphenyl‐2,6‐diethanones and their derivatives as potential agents targeting ERα. Four of the molecules synthesized exhibited preferential cytotoxicity in ERα+ cell line (MCF‐7) compared to ERβ+ cell line (MDA‐MB‐231). Molecular dynamics (MD) in combination with molecular mechanics‐generalized Born surface area (MM‐GBSA) methods could account for binding selectivity. Further cotreatment and E‐screen studies with known ER ligands—estradiol (E₂) and tamoxifen (Tam)—indicated isoform‐selective anti‐estrogenicity in ERα+ cell line which might be ER‐mediated. ERα siRNA silencing experiments further confirmed the ER selective nature of ligands.     

Investigation on the interaction of the toxicant,gentian violet,with bovine hemoglobin

Gentian violet (GV) is a well-known triarylmethane dye that is used in aquacultural, industrial and medicinal fields. But concerns in growing number have been paid to its potential health problems to human beings and its hazardous effects to environment. Herein, the toxic interaction of GV with bovine hemoglobin (BHb) was investigated by a series of spectroscopic methods and molecular modeling method. The fluorescence emission profile exhibited a remarkable quenching upon addition of GV to the buffered aqueous solution of BHb and the analysis of results revealed the dominant role of static quenching mechanism in GV–BHb interaction. The negative ΔH and positive ΔS values demonstrated that the electrostatic interactions mainly stabilized this toxicantprotein complex. Synchronous fluorescence, UV–Vis absorption and CD spectroscopic studies proved that the conformational change of BHb was induced by GV’s combination. Molecular modeling studies exhibited the binding mode of GV–BHb complex and the detailed information of related driving forces. During the ¹H nuclear magnetic resonance spectra (¹H NMR) study, the chemical shift perturbation and spin–lattice relaxation times of different protons were further used to investigate the interaction of GV with BHb and the results indicated that GV bound orientationally to BHb.     

In-silico screening for DNA-dependent protein kinase (DNA-PK) inhibitors: Combined homology modeling,docking, molecular dynamic study followed by biological investigation

DNA-dependent protein kinase (DNA-PK) is a key enzyme in non-homologous DNA end joining (NHEJ) repair pathway. The targeted inhibition of such enzyme would furnish a valuable option for cancer treatment. In this study we report the development of validation of enzyme homology model, and the subsequent use of this model to perform docking-based virtual screening against a database of FDA-approved drugs. The nominated highest ranking hits (Praziquantel and Dutasteride) were subjected to biological investigation. Additionally, molecular dynamic study was carried-out for binding mode exploration. Results of the biological evaluation revealed that both compounds inhibit the DNA-PK enzymatic activity at relatively high concentration levels with an IC₅₀ of 17.3 μM for praziquantel and >20 μM for dutasteride. Furthermore, both agents enhanced the anti-proliferative effects of doxorubicin and cisplatin on breast cancer (MCF7) and lung cancer (A549) cell lines. This result indicates that these two hits are good candidate as DNA-PK inhibitors and worth further structural modifications to enhance their enzyme inhibitory effects.     

Inhibitors of Bacillus anthracis edema factor

Edema factor (EF) is a calmodulin (CaM)-activated adenylyl cyclase (AC) toxin from Bacillus anthracis that contributes to anthrax pathogenesis. Anthrax is an important medical problem, but treatment of B. anthracis infections is still unsatisfying. Thus, selective EF inhibitors could be valuable drugs in the treatment of anthrax infection, most importantly shock. The catalytic site of EF, the EF/CaM interaction site and allosteric sites constitute potential drug targets. To this end, most efforts have been directed towards targeting the catalytic site. A major challenge in the field is to obtain compounds with high selectivity for AC toxins relative to mammalian membranous ACs (mACs). 3′-(N-methyl)anthraniloyl-2′-deoxyadenosine-5′-triphosphate is the most potent EF inhibitor known so far (K_i, 10 nM), but selectivity relative to mACs needs to be improved (currently ~5–50-fold, depending on the specific mAC isoform considered). AC toxin inhibitors can be identified in virtual screening studies based on available EF crystal structures and examined in cellular test systems or at the level of purified toxin using classic radioisotopic or non-radioactive fluorescence assays. Binding of certain MANT-nucleotides to AC toxins elicits large direct fluorescence- or fluorescence resonance energy transfer signals upon interaction with CaM, and these signals can be used to identify toxin inhibitors in competition binding studies. Collectively, potent EF inhibitors are available, but before they can be used clinically, selectivity against mACs must be improved. However, several methodological approaches, complementing each other, are now available to direct the development of potent, selective, orally applicable and clinically useful EF inhibitors.     

A new molecular paradigm in mycosis fungoides and Sézary syndrome

Mycosis Fungoides (MF) and Sézary Syndrome (SS) are clonal proliferations of mature T-cells manifesting as lymphoproliferative disorders in which the neoplastic cells show a strong propensity for skin-homing. While the predominant site of presentation in MF is the skin, the peripheral blood carries a significant tumor burden in Sézary Syndrome such that it resembles a “leukemic” disease. While the genetic basis of these diseases has been studied using different approaches in the previous years, recent genome-wide studies employing massively parallel sequencing techniques now offer new insights into the molecular pathogenesis of these diseases. In this chapter, we discuss the recent findings elucidating the genomic landscape of MF and SS. The pathways targeted by mutational alterations are discussed and a model for understanding the pathogenesis of these diseases is proposed. It is anticipated that prognostic stratification and therapeutic targeting based on mutational signatures will be achieved in the near future based on the improved understanding of the molecular pathogenesis of these diseases.     

First description of blaNDM-1, blaOXA-48, blaOXA-181 producing Enterobacteriaceae strains in Romania

We report the first isolation and characterization of several Enterobacteriaceae strains harboring bla_NDM-1, bla_OXA-48 and/or bla_OXA-181 genes in a Romanian emergency teaching hospital. Between January 2010 and September 2012 nine carbapenemase-producing Enterobacteriaceae strains were identified. The bla_NDM-1 gene was present in two Enterobacter cloacae strains, an Escherichia coli and two Klebsiella pneumoniae strains. One of these K. pneumoniae strains also harbored the bla_OXA-181 gene. Three other K. pneumoniae strains and one Serratia marcescens carried bla_OXA-48.     

耐多药结核病诊断方法研究进展

耐多药结核病的防治对于结核病的防控具有重要意义,已成为结核病防治的难点和热点问题。早期对结核病患者进行耐多药检测能够提高耐多药结核病患者的治疗成功率。耐多药结核病的诊断方法包括传统的培养方法及新型分子生物学诊断方法。作者对耐多药结核病的诊断方法进行综述,以期为耐多药结核病防治提供科学依据。