Medicinal Chemistry - Volume 7, Issue 2, 2011

Several protease inhibitors have reached the world market in the last fifteen years, dramatically improving the quality of life and life expectancy of millions of HIV-infected patients. In spite of the tremendous research efforts in this area, resistant HIV-1 variants are constantly decreasing the ability of the drugs to efficiently inhibit the enzyme. As a consequence, inhibitors with novel frameworks are necessary to circumvent resistance to chemotherapy. In the present work, we have created 3D QSAR models for a series of 82 HIV-1 protease inhibitors employing the comparative molecular field analysis (CoMFA) method. Significant correlation coefficients were obtained (q2 = 0.82 and r2 = 0.97), indicating the internal consistency of the best model, which was then used to evaluate an external test set containing 17 compounds. The predicted values were in good agreement with the experimental results, showing the robustness of the model and its substantial predictive power for untested compounds. The final QSAR model and the information gathered from the CoMFA contour maps should be useful for the design of novel anti-HIV agents with improved potency.

Local biosynthesis of estrogens, especially estradiol (E2), is thought to be important for the maintenance and growth of estrogen-sensitive diseases. To control E2 formation, we have investigated a series of epoxide and furanic E2 derivatives as inhibitors of 17β-hydroxysteroid dehydrogenase type 1 (17β-HSD1), the enzyme responsible for the conversion of estrone (E1) into E2. We report here a strategy to synthesize a series of E2-furanic derivatives from E1. An intermediate epoxide was first obtained and then reduced to give a furanic steroid, which allowed us to introduce a molecular diversity like alcohol, bromide, ester, acid and amide. The inhibition of the transformation of [14C]-E1 (100 nM) into [14C]-E2 by these compounds was first evaluated with homogenated HEK-293 cells overexpressing 17β-HSD1. The epoxide and butylamide derivatives showed the best inhibitions with 72% and 66%, respectively, at 10 μM. All furanic compounds showed a lower 17β-HSD1 inhibitory potency in intact T-47D breast cancer cells than in homogenated cells, but a great improvement of the inhibitory activity was observed for the epoxide, which gave 62% and 90% of inhibition of the [14C]-E1 (60 nM) into [14C]-E2 transformation at 1 and 10 μM, respectively.

5-aminosalicylic acid (5-ASA or mesalazine) is widely used for treatment of inflammatory bowel disease and considered to be cancer preventive. Still, the molecular mechanisms explaining its properties remain largely unknown, partially due to the lack of instrumentarium needed to identify its array of molecular targets. Modern OMICs-based technologies utilized in this study may serve as a powerful and unbiased tool to search for such targets. Here we demonstrate that 5-ASA alters β-catenin immunocomplex formation by changing complex binding of seven proteins including translation initiation factors eIF4b. OMICs-based cross-testing by reverse in-gel chemogenomics (utilizing 5-ASA's fluorescent properties), in-silico docking and surface plasmon resonance experiments identified binding of 5-ASA to eIF4e's capbinding pocket, a key regulatory site for protein synthesis. In-vitro translation experiments with rabbit reticulocytes confirmed a dose-dependent inhibition of protein syntheses by 5-ASA. By using two unbiased and independent OMICs-based experimental approaches two members of the cellular translation machinery, eIF4b and IF4e, were identified as targets of 5-ASA. Inhibition of protein syntheses is a previously unrecognized property of 5-ASA that may add to its antiinflammatory and anti-neoplastic activities.

Ethyl caffeate (EC), octyl caffeate(OC), benzyl caffeate(BC) and phenethyl caffeate(PC) were synthesized and evaluated for scavenging of superoxide anion, nitric oxide radical and 1,1-diphenyl-1-picrylhydrazyl radical(DPPH). Antioxidant activity was investigated with reducing power method. Pooled human liver microsome was used for investigating the effects on cytochrome P450 1A2 (CYP1A2) catalytic activities by using phenacetin as a substrate. Dixon and Cornish- Bowden plots were used for enzyme kinetic analysis. The EC, OC, BC and PC potentially inhibited superoxide anion, nitric oxide and DPPH radicals. IC50 values of superoxide anion scavenging of EC, OC, BC and PC were 16.42, 79.83, 123.69 and 123.69 μg/ml, respectively. EC was more potent than OC and BC in terms of nitric oxide radical scavenger: IC50 values of EC, OC and BC were 24.16, 37.34 and 52.64 μg/ml, respectively. In addition, the IC50 values of EC, OC, BC and PC on DPPH radical scavenging were 70.00, 184.56, 285.34 and 866.54 μg/ ml, respectively. The IC50 values of EC, OC, BC and PC on phenacetin O-deethylation were 124.98, 111.86, 156.68 and 31.05 μg/ml, respectively. Enzyme kinetics showed that the type of inhibition mechanism was mixed-type. The result of this study shows that caffeic acid ester analogues potentially scavenge free radicals and inhibit catalytic activity of CYP1A2. This may lead to important implications in the prevention of CYP1A2-mediated chemical carcinogenesis.

Lung cancer is a leading cause of death in human. Cancer stem cells have been regarded as basis for failure of current therapeutic options. Salinomycin was shown to kill these cancer stem cells in some types of cancer such as breast cancer and leukemia. The in vitro anticancer activities of salinomycin have been validated against the lung cancer cell line A549 via sulforhodamine B and colony formation assay. Salinomycin has been demonstrated to significantly rupture the in vitro lung cancer tumorospheres from ALDH positive A549 lung cells using flow cytometry. Expression of stem cell markers OCT-4, NANOG and SOX2 in ALDH positive A549 lung cells was decreased significantly by real-time RT-PCR analysis after 24 hour salinomycin treatment. Taken together, salinomycin may provide a promising approach for lung cancer chemotherapy.

The synthesis and antiproliferative activity of new coumarin-based benzopyranone derivatives containing basic amino side chain are described. The cytotoxicities against A549 and MCF-7 human cancerous cell lines were determined after 24, 48, 72h drug exposure employing MTT assay at concentrations ranging from 0-100 μM. The antiproliferative activities of these compounds were compared to tamoxifen (TAM), 4-hydroxytamoxifen (4-OHT), raloxifene (RAL), 17β- estradiol (E2) and Diethylstilbestrol (DES). In vitro results indicated that compounds 10 and 12 were the most potent showing significant inhibitory activities against these cell lines. Furthermore, their antiproliferative activity against MCF- 7 human breast cancer cell line is comparable to that of TAM, RAL and 4-OHT.

Human SP110 plays an important role in resisting intracellular pathogens, and hence has become an important drug target for preventing intracellular pathogen diseases, such as tuberculosis, hepatic veno-occlusive disease, and intracellular cancers. Unfortunately, so far little is known about the interactions of SP110 with the other proteins in a cell, which is considered to be the key for revealing its action mechanism and mediated pathway. Using both the genetic and structural analyses as well as the segment-docking approach, we have identified two proteins: the human remodeling and spacing factor 1 (RSF1) and the activating transcription factor 7 interacting protein (ATF7IP). They are very likely interacting with human SP110 during the process of viral infections. Owing to the close relationship of RSF1 with the chromatin remodeling and ATF7IP with the chromatin formation, it is logical to infer that human SP110 may be involved in the chromatin remodeling and formation as well. These findings may provide useful insights into the development of new drugs for treating and preventing intracellular pathogen diseases.

A series of 2-phenylbenzothiazoles has been synthesized either by i) condensation of different aromatic aldehydes with 2-aminothiophenol or ii) condensation of N-(2-chlorophenyl)benzothioamides in KOH catalyzed by potassium fericyanide. The structures of synthesized compounds were confirmed by IR, MS, and 1H-NMR. The results of biological activity screening showed that six compounds including 2-phenylbenzothiazol (1a), 2-(2-chlorophenyl)benzothiazole (1b), 2- (3-chlorophenyl)benzothiazole (1c), 2-(4-hydroxyphenyl)benzothiazole (1e), 2-(4-dimethylaminophenyl)benzothiazole (1h) and 2-(2,3,4-trimethoxyphenyl)benzothiazole (1i) exhibited significant antibacterial activities; two compounds (1a, 1e) exhibited antifungal activities. Especially, 1e showed considerable antimicrobial activity against both A. niger and F. oxysporum. The brominated derivative of 1e displayed extended spectrum against all four bacterial strains tested with lower MIC values. In vitro cytotoxicity of the synthesized compounds was evaluated on three cancer cell lines (A549, HT1080, MCF7-MDR). The results indicated that three compounds (1e, 1g, 1i) exhibited significant cytotoxic activity on A549 and MCF7-ADR cells (IC50, 10.07-13.21μg/ml). Brominated and nitrated derivatives (1k, 1l, respectively) of 1e exhibited even more potent cytotoxicity.

The reaction of a series of 1,2-diols with thionyl chloride led to bisnoradamantane sulfites in very good yields. The reaction has also been applied to related polycyclic scaffolds. The compounds have been tested for antiviral activity but none of them showed to be active. Several attempts to generate and trap SO from these polycyclic sulfites have been unsuccessful.

Dysfunction of the cochlea causes sensorineural hearing loss. Glucocorticoids have been clinically applied for sensorineural hearing loss of sudden onset, including idiopathic sudden sensorineural hearing loss, acoustic injury, Meniere's disease, and immune-mediated hearing loss. However, clinical studies on sudden sensorineural hearing loss have revealed conflicting results regarding the efficacy of glucocorticoids. The findings obtained from animal experiments have demonstrated that glucocorticoids exhibited protective effects on some types of cochlear injury, but there were limitations regarding glucocorticoid therapy. Recently, the actions of neurosteroids in the cochlea have drawn much attention from auditory researchers. Clinical and experimental studies of the auditory system have indicated that estrogens affect auditory perception. Furthermore, estrogens and dehydroepiandrosterone (DHEA) exhibit protective effects on cochlear injury. This article was aimed to give an overview of steroid treatment for protection of the inner ear against various cochlear injuries. Findings obtained from animal studies are focused on.