Medicinal Chemistry - Volume 13, Issue 4, 2017

Background: Despite the proof of principle that gene therapy can cure various monogenic diseases, limited clinical progress has been noted for gene therapy of the respiratory system. Certain anatomic features of the lungs, along with the suboptimal gene delivery vehicles utilized up to now, have significantly delayed successful clinical practice. Thus, the need for additional improvements towards safety and efficacy of the procedure is indispensable. Objective: The objective of this work was to review the progress and limitations of gene therapy in the treatment of lung disease with a focus on monogenic disease, chronic obstructive pulmonary disease and asthma and to present studies that provide a proof of principle that it works in different model systems and in patients. Method: A thorough search was performed on the aforementioned topic using Pubmed in order to identify relevant manuscripts. Several gene therapy studies for monogenic disorders affecting other organs or systems were also taken into consideration. Results: A hundred and thirty one papers were included. Inclusion criteria regarded novel gene transfer technologies of the past decade, as well as publications outlining the pitfalls that precluded earlier successful implementation of gene therapy for pulmonary diseases. Conclusion: Current gene transfer protocols and vector design require additional amelioration. The rapidly evolving and much promising technology of CRISPR/Cas9 might possibly overcome the hurdles posed to date for effective implementation of gene therapy and become the basis for the onset of new clinical trials.

Background: This review provides an overview of the cellular signaling of nitric oxide (NO) and prostanoids in vascular cells and the possible cross talk between their pathways, mainly in hypertension, since the imbalance of these two systems has been attributed to the development of some cardiovascular diseases. It also deals with the modulation of vasodilation induced by NO donors. NO is a well-known second messenger involved in many cellular functions. Objective: This work focuses on the cellular mechanisms involved in the vasodilation induced by NO and the role of prostanoids in contractile or relaxing vascular responses. Since the NO is produced by NO-synthase (NOS) or released from NO donors we also discussed the perspectives to cross talk between NO and COX pathways on the vascular tone control. Conclusion: In the vascular system, the NO produced by endothelial NO-synthase (eNOS) or released by NO donors acts in vascular smooth muscle cells, the binding of NO to Fe2+-heme of soluble guanylyl-cyclase (sGC) activates sGC and the production of cyclic guanosine-3-5- monophosphate (cGMP). The second messenger (cGMP) activates protein kinase G and the signaling cascade, including K+ channels. Activation of K+ channels leads to cell membrane hyperpolarization and Ca2+ channels blockade, which induce vascular relaxation. Moreover, the enzyme cyclooxygenase (COX) is also an important regulator of the vascular function by prostanoids production such as thromboxane A2 (TXA2) and prostacyclin (PGI2), which classically induce contraction and relaxation, respectively. Additionaly, studies indicate that the activity of both enzymes can be modulated by their products and reactive oxygen species (ROS) in cardiovascular diseases such as hypertension. The interaction of NO with cellular molecules, particularly the reaction of NO with ROS, determines the biological mechanisms of action and short half-life of NO. We have been working on the vascular effects of ruthenium-derived complexes that release NO. Our research group has published works on the vasodilating effects of ruthenium-derived NO donors and the mechanisms of vascular cells involved in the relaxation of the vascular smooth muscle in health and hypertensive rats. In our previous studies, we have compared the new NO donors synthesized by our group to SNP. It shows the cellular signaling of NO in the endothelial and vascular smooth muscle cells.

Background: Enormous success of antitumor agent cisplatin initiated interest in other organometallic complexes. A subclass of organometallic compounds termed metallocenes, characterized by a transition metal central atom (M) bound to cyclopentadienide (Cp-/[C5H5]-) ligands with the basic formula Cp2M, has gained increasing interest as promising anticancer agents. Objectives: This review summarizes the progress in the development of organometallic titaniumbased compounds focusing primarily on the evaluation of their cytotoxic activity and mechanism of action in relation to potential utilization as anticancer drugs. Results: Metallocenes bearing titanium as central atom were sorted according to their structure and modifications and their anticancer activity is further discussed. Conclusion: Titanocenes represent family of promising compounds exerting cytostatic activity. We suggest that their application not only as separate agents, but also in combination with newly developed carriers, e.g. nanomaterials, may lead to improvement of their delivery into tumor cells and following utilization in cancer treatment.

Background: The mitochondrial enzyme amyloid beta-binding alcohol dehydrogenase (ABAD) also known as 17β-hydroxysteroid dehydrogenase type 10 (17β-HSD10) has been connected with the pathogenesis of Alzheimer’s disease (AD). ABAD/17β-HSD10 is a binding site for the amyloid-beta peptide (Aβ) inside the mitochondrial matrix where it exacerbates Aβtoxicity. Interaction between these two proteins triggers a series of events leading to mitochondrial dysfunction as seen in AD. Methods: As ABAD’s enzymatic activity is required for mediating Aβ toxicity, its inhibition presents a promising strategy for AD treatment. In this study, a series of new benzothiazolylurea analogues have been prepared and evaluated in vitro for their potency to inhibit ABAD/17β-HSD10 enzymatic activity. The most potent compounds have also been tested for their cytotoxic properties and their ability to permeate through blood-brain barrier has been predicted. To explain the structureactivity relationship QSAR and pharmacophore studies have been performed. Results and Conclusion: Compound 12 was identified being the most promising hit compound with good inhibitory activity (IC50 = 3.06 ± 0.40 µ M) and acceptable cytotoxicity profile comparable to the parent compound of frentizole. The satisfactory physical-chemical properties suggesting its capability to permeate through BBB make compound 12 a novel lead structure for further development and biological assessment.

Background: Tetrazole derivatives such as 1-substituted dinitrobenzyl tetrazoles and their oxa and selanyl analogs have previously been studied against drug-susceptible and multidrugresistant mycobacteria. In addition, other tetrazole derivatives have been shown to inhibit CTX-M class A β-lactamases. Objective: To study the antibacterial activity of 5-substituted aryl 1H-tetrazole derivatives. Methods: The antibacterial activity of several known 5-substituted aryl 1H-tetrazole derivatives was evaluated against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The activity was assessed by determining the minimum inhibitory concentration of these tetrazole derivatives and comparing them to the known antibiotics amoxicillin, trimethoprim and sulfamethoxazole. Results: Some derivatives showed significant antibacterial activity with the most active derivatives exhibiting a minimum inhibitory concentration (MIC) of 125-250 μg/mL against Staphylococcus aureus and Escherichia coli. Using some of these tetrazole compounds in combination with trimethoprim led to a synergistic effect that gave MIC values ranging from 0.24-1.95 μg/mL against Escherichia coli and 3.91-31.3 μg/mL against Staphylococcus aureus. The tetrazole derivatives were prepared in an isopropanol/water mixture using microwave heating at 160 oC for 1h. The cycloaddition between organonitriles and sodium azide was catalyzed by indium chloride. Conclusion: This study shows a significant synergistic effect between the tetrazole compounds tested and trimethoprim which could be used to potentially develop new antibacterial agents.

Background: Several pyrazolopyridines possess promising pharmacological activities, mainly attributed to their antagonistic nature towards the natural purines in many biological processes. Cytotoxicity and anticancer potential of this class of compounds are mainly related to induction of apoptotic cell death and inhibition of protein kinases. Objectives: This prompted us to design, synthesize and study the antiproliferative activity of a number of new 3,7-disubstituted pyrazolo[3,4-c] pyridines. Methods: 2-amino-3-nitro-4-picoline was suitably modified and ring closed to provide 7-chloropyrazolo[ 3,4-c]pyridine. Iodination of this derivative was followed by the insertion of 3-aryl substituents via Suzuki coupling and aromatic nucleophilic substitution of the 7-chloro group by the appropriate amines. The antiproliferative activity of the target compounds was evaluated against A2058 melanoma, DU145 and PC3 prostate cancer cell lines. Flow cytometric analysis of DNA content for selected compounds was performed, after incubation of exponentially growing PC-3 cells. Results: Eighteen new pyrazolopyridines have been synthesized and fully characterized. Among them, the majority of the 3-(3-fluorophenyl) derivatives exhibit interesting antiproliferative activity, with IC50 values in the range of 3.0-16.0 μ M and present reasonable SARs. Cell-cycle perturbations revealed that the most active derivative 12a blocks cells at the S phase. Conclusion: 3-(3-Fluorophenyl)-7-(4-methylpiperazin-1-yl)-1H-pyrazolo[3,4-c]pyridine (12a) and the corresponding 1-(4-methoxybenzyl)- analogue (11a) possess interesting antiproliferative activity against all cell lines tested. Derivatives bearing this substitution pattern can be considered as useful leads for further biological evaluation.

Background: The modification of steroidal structure is commonly used to change the biological activity of steroids in medicinal chemistry. Some steroids containing heterocycles exhibit distinct cytotoxicity against various cancer cell lines and have been receiving wide attention over the years by medicinal chemists for drug discovery. Methods: Using pregnenolone and stigmasterol as starting materials, via different chemical reaction, two series of heterosteroids with side chain of 20- and 22-hydrazone aromatic cycles or heterocycles in their structures were synthesized and characterized by IR, NMR and HRMS. The antiproliferative activity of the compounds in vitro was evaluated against human HT-29, HeLa, Bel 7404 and SGC 7901 cancer cells by MTT assays. Results: The steroidal compounds with side chain of 20-hydrazone aromatic cycles or heterocycles exhibited distinct cytotoxicity. However, analogues with the side chain of 22-hydrazone resulted in a dramatic decrease of the cytotoxicity. The result of Annexin V assay showed that the 20-hydrazone compounds were potent apoptotic inducers against these carcinoma cells. Conclusion: Steroidal compounds with the side-chain of 20-hydrazone aromatic heterocycles exhibit distinct antiproliferative activity in vitro. However, the compounds with the side-chain of 22-hydrazone aromatic heterocycle decreased the cytotoxicity of the compounds.

Background: Pathogenic microbial diseases are now the key virulence in our daily life. Significant research has been carried out in order to trigger the bacterial infections. Amongst the organic molecules, oxazolone and derivatives were found to have excellent bioactivities including antimicrobial activities. Methods: By keeping in mind the considerable antimicrobial activities of class benzoxazolones, a series of benzoxazolone derivatives 3-16 have been synthesized. Out of which five compounds 10, 11, 14, 15, and 16 were new synthetic derivatives whereas compounds 9, 12, and 13 were already known compounds. These compounds have been synthesized by refluxing of amino phenol and 1,1-carbonyldiimidazole1 (C3H3N2)2CO) (CDI) in a dry THF and then treated with commercially available acid chloride. The structures of the compounds were elucidated on the basis of 1H-NMR, EIMS and elemental analysis. All the compounds were screened for their antibacterial activities and tested by agar well diffusion method. Results: Compounds 14 and 16 showed good activity against S. aureus. Compound 5 showed good while 14 and 16 were found to be most active against E. coli using cefuroxime as a standard. Antifungal activities were carried out by using standard drug nystatin and compounds 4, 5, 9, 11 and compound 12 was found to be active against C. albicans. Compounds 4, 5, 9 and compound 10 showed good activities while 7, 11, and compound 13 showed excellent activities against Chrysosporium sp. Compounds 6, 7 and compound 12 were found to be most active against A. niger and A. flavus, respectively. Conclusion: A number of derivatives were identified to have potent antimicrobial activities and may serve as lead compounds for future research.

Background: Schiff bases have been greatly studied in biological field due to their wide range of pharmacological activities, such as antitubercular and antitumour. In the search of novel antitubercular agents, several compounds containing pharmacophoric group of ethambutol have been synthesized and evaluated against mycobacteria species causing tuberculosis. In this work, we investigate whether ethylenediamine, Schiff base as well as nitro group together could contribute to the formation of novel molecules with dual biological activities: antitubercular and anticancer. Methods: A series of Schiff bases (3-12) derived from p-nitrophenylethylenediamine (1) as well as N1,N2-bis(4-nitrophenyl)ethane-1,2-diamine (2) were synthetized and assayed for their action against Mycobacterium tuberculosis H37Rv strain and the human tumour cell lines SF-295 (glioblastoma multiforme), HCT-116 (colon adenocarcinoma) and OVCAR-8 (ovarian cancer). Results: Among the compounds that showed antimycobacterial effects, 4 was more active than ethambutol, the antitubercular drug used as positive control. Also, compounds 1, 8, 10 and 12 were able to reduce strongly the viability of the tumour cell lines at 5 μgmL-1. Conclusion: According to studies, some modifications on p-nitrophenylethylenediamine (1) were an effective strategy to obtain compounds with antiproliferactive activities. Also, Schiff base 4 proved to be the lead antitubercular compound.

Background: Although a number of agents can achieve high response in acquired immunodeficiency syndrome (AIDS) patients, safer and more active HIV inhibitors are still needed for the growing number of patients infected with resistant HIV virus strains. GW678248 is one of the most potent benzophenone derivatives, exhibiting high potency against a panel of HIV- 1 virus (wild-type, K103N mutant, Y181C, etc.) at 1 nmol/L concentrations. However, the safety issues associated with rash and liver metabolic enzymes ultimately led to discontinue its further deve-lopment. As a continuation of our structural modifications on this template, in this manuscript, a new series of benzophenones are described as potential HIV inhibitors. Methods: All the title molecules were synthesized according to the routes in Scheme 1 and Scheme 2, and were tested for anti-HIV-1 activity using the MTT method. In the molecular simulation, the docking program of AutoDock 4.0.1 in parallel with the default parameters were used. Results: A series of novel benzophenone derivatives (BPs) with nanomolar anti-HIV-1 activity were identified. Of these inhibitors, analogue 10i (EC50 = 2.9 nmol/L), the most active inhibitor, was comparable to the lead compound GW678248 in inhibiting the wild-type HIV-1 virus. Additionally, analogue 13b, which not only exhibited strong inhibitory activity against the HIV-1 virus (EC50 = 4.2 nmol/L), but also has very low cytotoxicity with a TI value of more than 219178.1 was also discovered. Conclusion: This study led to the identification of a series of benzophenone derivatives with nanomolar level of anti-HIV-1 activity. Analogues 10i and 13b, with low cytotoxicity along with high activity are worthy of further development.