Medicinal Chemistry - Volume 14, Issue 1, 2018

Background: USP7 (ubiquitin specific protease 7, also known as HAUSP) is one of the deubiquitinating enzymes (DUB) that reverses ubiquitination and spares substrate proteins from degradation. Methods: After a brief introduction of ubiquitin-proteasome system (UPS) and human DUB, this review focuses on the structural and functional complexity of USP7 in tumor development and progression. Afterwards, physiological regulatory mechanisms and manipulation strategies for USP7 are elaborated. Finally, we discuss the advances and difficulties of USP7 as a novel therapeutic target for cancer. Results: It is mostly concerned that USP7 regulates the dynamics of the p53 and Mdm2 network by deubiquitinating both p53 and its E3 ubiquitin ligase, Mdm2. Recently, USP7 has also been recognized as a regulator of many other tumor associated proteins such as FOXO, PTEN and Claspin, consequently being involved in cell cycle control, DNA damage response, apoptosis and many other cellular processes. Consistently, aberrant USP7 expression and activity have been connected to various types of cancers, which along with lots of validating genetic and functional experiments make this enzyme a compelling target for the treatment of cancer. Currently disclosed inhibitor discovery programs and relevant research have identified several synthetic small molecules, natural compounds, small peptides and one ubiquitin variant that have specific USP7 inhibitory effects and considerable antitumor activities. Conclusion: Taken together, USP7 is a promising therapeutic target and USP7 inhibitors hold promise as a new approach to cancer therapy.

Background: Fluorescent compounds had gained strong attention due to their wide and appealing applications. Microscopic techniques and visualization are good examples among others. Introduction of fluorescent dyes into microbiology opens the possibility to observe tissues, organisms or organelle with exceptional sensitivity and resolution. Probes for detection of biologically relevant metals as zinc, iron or copper seems to be particularly important for drug design and pharmaceutical sciences. Objective: Quinoline derivatives are well known for their good metal affinity and wide spectrum of biological activity. In this regard, molecular sensors built on this scaffold may be useful not only as analytical but also as therapeutic agents. Methods: In the present review, application of quinoline moiety in designing of novel fluorescent probes for zinc is presented and discussed. Results: Zinc cations are relevant for vast majority of processes and recently attract a great deal of attention for their role in neurodegenerative diseases. Compounds interacting with Zn2+ may be used for early diagnosis of such disorders, for example the Alzheimer disease. Conclusion: Quinoline-based zinc probes may exert some beneficial role in organism acting as theranostic agents. First preliminary drugs for Alzheimer therapy that are based on quinoline moiety are good example of this trend.

As lifespan tendency is increasing, age-related diseases are becoming a burden to the society and health care system. Mostly incurable, constitute a subject of researchers' work. In this review, the insight into the problem of Alzheimer Disease (AD) diagnostics will be given. The unquestionable diagnosis is possible only during a post-mortem examination. AD is known as one of the forms of dementia and its differentiation from mild cognitive impairments has to be improved. Despite a great diagnostic progress during last decades, medicine still needs more accurate tools for an early detection of this incurable disease. It is hoped that this strategy will enable an administration of more aggressive therapy preventing AD development. Nowadays, pharmacotherapy is based mainly on symptomatic treatment which is not able to reverse pathological changes caused by the disease. Hence, more accurate identifying testing and monitoring methods are crucial to reveal new therapeutic targets. The most popular techniques present for detecting local brain functional changes use nuclear medicine imaging devices: Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT). Constant process of improving is not possible without new radiotracers. Magnetic Resonance Imaging (MRI) is a tool for an assessment of structural changes in brain tissue. However, providing satisfying results, these methods are not completely specific and accurate. As very promising hallmarks of AD enhancing high accuracy of testing, biomarkers – tau tangles and β-amyloid plaques have been found. At the present time they are being used only as an additional examination, one day they may become a gold standard of AD diagnostics.

Background: Heat shock protein 90 is a molecular chaperone required for the stability and function of several client proteins that promote cancer cell growth and/or survival. Discovery of Hsp90 inhibitors has emerged as an attractive target of research in cancer therapeutics. Natural products like geldanamycin and radicicol are established Hsp90 inhibitors, but face limitations with toxicity and inactivity, by in vivo studies respectively. However, they lay the logical starting point for the design of novel synthetic or semi-synthetic congeners as Hsp90 inhibitors. Objective: In this article, the structure based drug design of substituted 2-aryl/heteroarylidene-6- hydroxybenzofuran-3(2H)-one analogues to optimize and mimic the pharmacophoric interactions of the valid Hsp90 inhibitor radicicolis focused. Method: In silico docking study was performed by Surflex dock-Geom (SYBYL- X 1.2 drug discovery suite) and the designed ligands were chemically synthesized by conventional method using resorcinol and chlororesorcinol as starting materials. Two dimensional chemical similarity search was carried out to identify the chemical space of ‘SY’ series in comparison with reported Hsp90 inhibitors. The in vitro cell proliferation assay (resazurin reduction method) and proteomic investigation (DARTS) was carried out on whole cell lysate to evaluate anticancer activity. Results: The chemical structures of all the synthesized compounds were confirmed by IR, 1H-NMR and Mass spectral analysis. The results of chemical similarity search show that SY series fit it in the chemical space defined by existing Hsp90 inhibitors. In vitro cell proliferation assay, against human melanoma and breast cancer cell lines, identified ‘SY3’ as the promising anticancer agent amongst the series. Conclusion: Docking studies, 2D chemical similarity search, resazurin reduction assay and qualitative proteomic analysis identify ‘SY3’as a promising Hsp90 inhibitor amongst the series.

Background: Triazoles and their fused derivatives are an important class of compounds that exhibit interesting biological properties, such as antiasthmatic, antimicrobial, antifungal, analgesic, antiallergic, antiinflammatory, herbicidal, plant growth regulative activity, and anti-HIV-1 activities. Moreover, anticancer activity of 1,2,4-triazole containing derivatives has been documented. Due to the fact a convenient approach toward polycyclic frameworks containing fused 1,2,4-triazoles was described. Objective: The objective of this article is the synthesis of new pyrazolo[4,3-e]triazolo[4,5- b][1,2,4]triazine derivatives with potential antiproliferative activity. Methods: Cancer cell proliferation was analysed by means of MTT assay after 96 h treatment. IC50 was calculated using computerized linear regression analysis of quantal log doseprobit functions, according to the method of Litchfield and Wilcoxon. X-ray data were collected on the Bruker SMART APEX II CCD diffractometer; The structure was solved by direct methods using SHELXS-2013 and refined by full-matrix least-squares with SHELXL-2014/7. All calculations were performed using WINGX version 2014.1 package. Results: The series of pyrazolo[4,3-e]triazolo[4,5-b][1,2,4]triazine derivatives were synthesized. MTT assay revealed that the compounds inhibited cancer cells growth at concentrations below 10 μM. The tested compounds showed higher antiproliferative activity than popular cytostatics cisplatin (lung carcinoma) and 5-fluorouracil (colon adenocarcinoma). X-ray examinations showed that final products in the crystalline phase have a linear form. Conclusion: In the paper we have reported the synthesis and spectroscopic analysis of new condensed tricyclic derivatives of the pyrazolo[4,3-e]triazolo[4,5-b][1,2,4]triazine. MTT analysis revealed concentration-dependent decrease in lung A549 and colon LS180 cancer cells proliferation. In order to explain the molecular mechanisms involved in anticancer activity of pyrazolo[4,3- e]triazolo[4,5-b][1,2,4]triazine derivatives, our research will be continued.

Background: Acute myeloid leukemia (AML) is the most common hematological malignancy in adults, characterized by distorted proliferation and development of myeloid cells and their precursors in the bone marrow. Nitidine chloride, a naturally occurring alkaloid, has been identified to possess antitumor activity. However, the effects of nitidine chloride on acute myeloid leukemia cells and its underlying mechanisms have not been elucidated. Here we investigated the cellular and molecular mechanism of the anti-leukemic effects of nitidine chloride. Methods and Results: Nitidine chloride treatment for 48 consecutive hours exhibited a timedependent and dose-dependent growth inhibition activity against AML cells by inducing cell cycle arrest and apoptosis. Moreover, nitidine chloride downregulated Cyclin B1, CDK1 and Bcl-2, upregulated p27 and Bax, inactivated PARP, activated Caspase-3 in AML cells. We further demonstrated that growth inhibition activity of nitidine chloride in AML cells is partially via inhibiting the phosphorylation of AKT and ERK. Conclusion: In conclusion, our data suggest that nitidine chloride could be an effective therapeutic agent against AML via cell cycle arrest and apoptosis.

Background: Osteoporosis (OP) is a common bone disease, most often diagnosed in post-menopausal women. The majority of OP treatments are focused on manipulation of the patient's hormone levels, therefore, they are associated with significant adverse effects. Objective: The study aimed to design, synthesize and evaluate the β-catenin translocation capability and the alkaline phosphatase (ALP) activation activity of 7H-thiazolo[3,2-b]-1,2,4-triazin-7-one derivatives. Method: The styrene derivatives were synthesized as raw materials, followed by oxidation and condensation reactions, in which 6-aryl-3-thioxo-3,4-dihydro-1,2,4-triazin-5(2H)-one derivatives (1) were obtained. The 3,6-diaryl-7H-thiazolo[3,2-b]-1,2,4-triazin-7-ones (2) were obtained by a condensation reaction of compound 1 with substituted phenacyl chlorides in acetic acid. The target compounds 3,6-diaryl-7H-thiazolo[3,2-b]-1,2,4-triazin-7-ones (3a-3c) were prepared by compound 2 with substituted alkyl chloride by Williamson reaction. As to 6-benzyl-3-aryl-7H-thiazolo[3,2- b]-1,2,4-triazin-7-one derivatives as the target compounds, the benzaldehyde and acetylglycine used as raw materials, followed by Erlenmeyer-Plochl reaction, condensation reaction, hydrolysis reaction, condensation reaction, 6-benzyl-3-thioxo-3,4-dihydro-1,2,4-triazin-5(2H)-one derivatives were obtained, and were converted to the target compounds 6-benzyl-3-(hydroxylaryl)-7Hthiazolo[ 3,2-b]-1,2,4-triazin-7-one derivatives (5a-5d) using reaction with substituted α-phenacyl chlorides. Finally, Williamson reaction were used to yield 6-benzyl-3-aryl-7H-thiazolo[3,2-b]- 1,2,4-triazin-7-ones as target compounds (6a-6e). The β-catenin translocation capability and the ALP activation activity were tested, and the glycogen synthase kinase-3 (GSK-3) inhibition was simulated by molecular docking. Results: Fourteen 7H-thiazolo[3,2-b]-1,2,4-triazin-7-one derivatives were synthesized and characterized by mass spectra, proton NMR and infrared spectra, the β-catenin translocation capability and the ALP activation activities of the target compounds were tested and calculated. The EC50 value of the ALP activation activity of 6-(4-chlorobenzyl)-3-{4-[(2-dimethylamino)-2- oxoethoxy]phenyl}-7H-thiazolo[3,2-b]-1,2,4-triazin-7-one (6b) was 11.283 μM. The molecular docking results have showed that the target compounds would be GSK-3 inhibitors. Conclusion: Based on the results of the biological activity test, the target compounds have exhibited the β-catenin translocation capability and the ALP activation activity.

Background: Parkinson's disease (PD), a debilitating and progressive disorder, is among the most challenging and devastating neurodegenerative diseases predominantly affecting the people over 60 years of age. Objectives: To confront PD, an advanced and operational strategy is to design single chemical functionality able to control more than one target instantaneously. Methods: In this endeavor, for the exploration of new and efficient inhibitors of Parkinson's disease, we synthesized a series of quinoline carboxylic acids (3a-j) and evaluated their in vitro monoamine oxidase and cholinesterase inhibitory activities. The molecular docking and in silico studies of the most potent inhibitors were performed to identify the probable binding modes in the active site of the monoamine oxidase enzymes. Moreover, molecular properties were calculated to evaluate the druglikeness of the compounds. Results: The biological evaluation results revealed that the tested compounds were highly potent against monoamine oxidase (A & B), 3c targeted both the isoforms of MAO with IC50 values of 0.51 ± 0.12 and 0.51 ± 0.03 μM, respectively. The tested compounds also demonstrated high and completely selective inhibitory action against acetylcholinesterase (AChE) with IC50 values ranging from 4.36 to 89.24 μM. Among the examined derivatives, 3i was recognized as the most potent inhibitor of AChE with an IC50 value of 4.36 ± 0.12 ±μM. Conclusion: The compounds appear to be promising inhibitors and could be used for the future development of drugs targeting neurodegenerative disorders.

Background: Despite the availability of a variety of antibacterial agents, re-emergence of pathogenic bacteria is still a serious medical concern. So, identification of new, safer, and selective antibacterial agents is the key interest in the medicinal chemistry research. Method: To explore the antimicrobial activity of coumarin-3-carboxamides for a range of bacterial and fungal strains, twenty eight derivatives were synthesized by the reaction of coumarin-3-carboxylic acid with a variety of aniline derivatives in the presence of 1,1'-carbonyldiimidazole (CDI). All compounds were structurally characterized by different spectroscopic techniques EI-MS, HREI-MS, 1H-NMR, 13C-NMR, and evaluated for antimicrobial activities (antibacterial and antifungal). Results: A number of compounds showed good to weak antibacterial activity against various strains of Gram-positive and Gram-negative bacteria. Amongst them, compound 28 displayed noticeable inhibition against five strains of Gram-positive (Bacillus subtilis, Corynebacterium xerosis, Staphylococcus aureus, Streptococcus faecalis, and MRSA) and four strains of Gram-negative bacteria (Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterobacter aerogene, and Shigella dysenteria). However, none of the compounds showed antifungal activity against tested fungi. MIC values were determined for most of the active compounds 2, 15, and 28 against particular bacterial cultures. In silico studies were performed on the most active compound 28 in order to specify and verify the target for antibacterial activity of synthetic coumarin-3-carboxamide derivatives. The cytotoxicity of these compounds on mammalian cells is unknown yet but we are planning to carry out research on the cytotoxic aspect of these compounds in future. Conclusion: The newly identified compounds may serve as lead molecules for the future research regarding the identification of new antibacterial agents.