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[Image: see text] Innovation in medicinal chemistry has been at the heart of ACS Medicinal Chemistry Letters since the journal’s founding 10 years ago. In his inaugural editorial, Editor-in-Chief Dennis Liotta laid out a vision for the journal to become the “premier international journal for rapid communication of cutting-edge studies,” and, after 10 years, it has become exactly that. The great hope of drug discovery scientists is that their innovations will lead to new therapeutics to treat unmet medical needs. In the spirit of innovation and in celebration of the recent 10th anniversary of ACS Med. Chem. Lett., we highlight five therapeutics that were first reported or first comprehensively characterized within ACS Med. Chem. Lett.. This overview also serves to introduce the expansion of the scope of the Innovations article type to include Topical Innovations. With this extension, the journal hopes to provide a forum to showcase concise (rather than comprehensive) reviews of topics that are both timely and of great interest to the medicinal chemistry community. Moreover, these articles will emphasize the next steps to move the field toward new areas of interest in medicinal chemistry. Appropriate topics might include case studies of clinical candidates or approved drugs, new assay technologies in drug discovery, novel target classes, and innovative new approaches towards modulation of human physiology. Since its founding 10 years ago, ACS Med. Chem. Lett. has established itself as a venue for the rapid communication of studies in medicinal chemistry and drug discovery. There have been several drugs and clinical candidates that were first reported or first comprehensively characterized in ACS Med. Chem. Lett. In celebration of the 10th anniversary of ACS Med. Chem. Lett. this Topical Innovations article highlights five of these compounds: Ivosidenib, Siponimod, Glasdegib, Parsaclisib, and Dabrafenib.

[Image: see text] Zika virus (ZIKV) infection, which initially was endemic only in Africa and Asia, is rapidly spreading throughout Europe, Oceania, and the Americas. Although there have been enormous efforts, there is still no approved drug to treat ZIKV infection. Herein, we report the synthesis and biological evaluation of agents with noncompetitive mechanism of the ZIKV NS2B/NS3 protease inhibition through the binding to an allosteric site. Compounds 1 and 2 showed potent activity in both enzymatic and cellular assays. Derivative 1 efficiently reduced the ZIKV protein synthesis and the RNA replication and prevented the mice from life-threatening infection and the brain damage caused by ZIKV infection in a ZIKV mouse model.

The Wnt/β-catenin pathway is often found deregulated in cancer. The aberrant accumulation of β-catenin in the cell nucleus results in the development of various malignancies. Specific drugs against this signaling pathway for clinical treatments have not been approved yet. Herein we report inhibitors of β-catenin signaling of potential therapeutic value as anticancer agents. Ethyl 4-((4-(trifluoromethyl)phenyl)sulfonamido)benzoate (compound 14) inhibits the effect on Wnt reporter with an IC50 value of 7.0 μM, significantly reduces c-MYC levels, inhibits HCT116 colon cancer cell growth (IC50 20.2 μM), does not violate Lipinski and Veber rules, and shows predicted Caco-2 and MDCK cell permeability Papp >500 nm s-1 . Compound 14 seems to have potential for the development of new anticancer therapies.

[Image: see text] We report here the synthesis and human carbonic anhydrases (CA, EC 4.2.1.1) inhibitory properties of a series of 4′-substituted 1,1′-biphenyl-4-sulfonamides incorporating a 2″- or 3″-amino- or carboxyphenyl unit. Most compounds showed significant variations in their inhibition profiles against CA II and IX when compared to previously reported analogs 12–18 bearing a 4″-amino or a 4″-carboxy group. In particular, compounds 1–11 showed considerable improvement of the CA II inhibitory efficacy with K(I) values in the subnanomolar range (K(I)s spanning between 0.57 and 31.0 nM), a drop of activity against CA IX (K(I)s in the range 92.0 to 555.7 nM) and were as potent as 12–18 toward CA I (K(I)s in the range 5.9–217.7 nM). Docking and molecular dynamics were used to gain insights on the inhibition profiles. The reported inhibition data show that 1–11 have potential as novel agents to treat ocular pathologies, such as glaucoma, because of the potent and selective targeting of CA II, which is the isoform most implicated in this disease.

We designed new 3-arylthio- and 3-aroyl-1H-indole derivatives 3–22 bearing a heterocyclic ring at position 5, 6 or 7 of the indole nucleus. The 6- and 7-heterocyclyl-1H-indoles showed potent inhibition of tubulin polymerization, binding of colchicine to tubulin and growth of MCF-7 cancer cells. Compounds 13 and 19 inhibited a panel of cancer cells and the NCI/ADR-RES multidrug resistant cell line at low nanomolar concentrations. Compound 13 at 50 nM induced 77% G2/M in HeLa cells, and at 20 nM caused 50% stable arrest of mitosis. As an inhibitor of HepG2 cells (IC50 = 20 nM), 13 was 4-fold superior to 19. Compound 13 was a potent inhibitor of the human U87MG glioblastoma cells at nanomolar concentrations, being nearly one order of magnitude superior to previously reported arylthioindoles. The present results highlight 13 as a robust scaffold for the design of new anticancer agents.

The WNT pathway interconnects a network of signaling events involved in a huge plethora of cellular processes, from organogenesis to tissue homeostasis. Despite its importance, the exiguity of organic drugs directly targeting the members of the Frizzled family of WNT receptors has hampered progress across the whole spectrum of biological fields in which the signaling is involved. We here present FzM1.8, a small molecule acting as an allosteric agonist of Frizzled receptor FZD4. FzM1.8 derives from FzM1, a negative allosteric modulator of the receptor. Replacement of FzM1 thiophene with a carboxylic moiety induces a molecular switch in the lead and transforms the molecule into an activator of WNT signaling. We here show that, in the absence of any WNT ligand, FzM1.8 binds to FZD4, promotes recruitment of heterotrimeric G proteins, and biases WNT signaling toward a noncanonical route that involves PI3K. Finally, in colon cancer cells, we prove that the FZD4/PI3K axis elicited by FzM1.8 preserves stemness and promotes proliferation of undifferentiated cells.

Glioblastoma (GBM) is characterized by a poor response to conventional chemotherapeutic agents, attributed to the insurgence of drug resistance mechanisms and to the presence of a subpopulation of glioma stem cells (GSCs). GBM cells and GSCs present, among others, an overexpression of antiapoptotic proteins and an inhibition of pro-apoptotic ones, which help to escape apoptosis. Among pro-apoptotic inducers, the Bcl-2 family protein Bax has recently emerged as a promising new target in cancer therapy along with first BAX activators (BAM7, Compound 106, and SMBA1). Herein, a derivative of BAM-7, named BTC-8, was employed to explore the effects of Bax activation in different human GBM cells and in their stem cell subpopulation. BTC-8 inhibited GBM cell proliferation, arrested the cell cycle, and induced apoptosis through the induction of mitochondrial membrane permeabilization. Most importantly, BTC-8 blocked proliferation and self-renewal of GSCs and induced their apoptosis. Notably, BTC-8 was demonstrated to sensitize both GBM cells and GSCs to the alkylating agent Temozolomide. Overall, our findings shed light on the effects and the relative molecular mechanisms related to Bax activation in GBM, and they suggest Bax-targeting compounds as promising therapeutic tools against the GSC reservoir.

New indolylarylsulfone HIV-1 NNRTIs were synthesized to evaluate unexplored substitutions of the benzyl/phenylethyl group linked at the indole-2-carboxamide. Against the NL4-3 HIV-1 WT strain, 17 out 20 compounds were superior to NVP and EFV. Several compounds inhibited the K103N HIV-1 mutant strain at nanomolar concentration and were superior to EFV. Some derivatives were superior to EFV against the Y181C and L100I HIV-1 mutant strains. Against the NL4-3 HIV-1 strain, the enantiomers 24 and 25 showed small differences of activity. In contrast, 24 turned out significantly more potent than 25 against the whole panel of mutant HIV-1 strains. The docking studies suggested that the difference in the observed inhibitory activities of 24 and 25 against the K03N mutation could be due to a kinetic rather than affinity differences.

Targeted approaches aiming at modulating NHERF1 activity, rather than its overall expression, would be preferred to preserve the normal functions of this versatile protein. We focused our attention on the NHERF1/PDZ1 domain that governs its membrane recruitment/displacement through a transient phosphorylation switch. We herein report the design and synthesis of novel NHERF1 PDZ1 domain inhibitors. These compounds have potential therapeutic value when used in combination with antagonists of β-catenin to augment apoptotic death of colorectal cancer cells refractory to currently available Wnt/β-catenin-targeted agents.

Tubulin is the primary target of an ever growing number of natural, semisynthetic and synthetic products as potential anticancer agents. The mechanisms of interaction of these molecules with tubulin are varied. These drug classes have shown to inhibit effectively several cancer types with IC50 from midmicromolar to low nanomolar concentrations. However, some limiting obstacles still remain, such as the development of multidrug resistance and cytotoxicity. We have reviewed recent advances in different classes of tubulin binding agents, including colchicine site agents, Vinca alkaloids, tryprostatins, moroidin, hemiasterlin, diazonamide, taxanes, epothilones and laulimalide.

New 1,1'-biphenylsulfonamides were synthesized and evaluated as inhibitors of the ubiquitous human carbonic anhydrase isoforms I, II, IX, XII, and XIV using acetazolamide (AAZ) as reference compound. The sulfonamides 1-21 inhibited all the isoforms, with Ki values in the nanomolar range of concentration, and were superior to AAZ against all of them. X-ray crystallography and molecular modeling studies on the adducts that compound 20, the most potent hCA XIV inhibitor of the series (Ki = 0.26 nM), formed with the five hCAs, provided insight into the molecular determinants responsible for the high affinity of this molecule toward the target enzymes. The results pave the way to the development of 1.1'-biphenylsulfonamides as a new class of highy potent hCA XIV inhibitors.

We designed 3-aroyl-1,4-diarylpyrrole (ARDAP) derivatives as potential anticancer agents having different\ud substituents at the 1- or 4-phenyl ring. ARDAP compounds exhibited potent inhibition of tubulin polymerization, binding of\ud colchicine to tubulin, and cancer cell growth. ARDAP derivative 10 inhibited the proliferation of BCR/ABL-expressing KU812\ud and LAMA84 cells from chronic myeloid leukemia (CML) patients in blast crisis and of hematopoietic cells ectopically\ud expressing the imatinib mesylate (IM)-sensitive KBM5-WT or its IM-resistant KBM5-T315I mutation. Compound 10 minimally\ud affected the proliferation of normal blood cells, indicating that it may be a promising agent to overcome broad tyrosine kinase\ud inhibitor resistance in relapsed/refractory CML patients. Compound 10 significantly decreased CML proliferation by inducing\ud G2/M phase arrest and apoptosis via a mitochondria-dependent pathway. ARDAP 10 augmented the cytotoxic effects of IM in\ud human CML cells. Compound 10 represents a robust lead compound to develop tubulin inhibitors with potential as novel treatments for CML.

The function of p53 protein, also known as "genome guardian", might be impaired by the overexpression of its primary cellular inhibitor, the murine double minute 2 protein (MDM2). However, the recent finding that MDM2-selective inhibitors induce high levels of its homologue MDM4, prompt us to identify, through a receptor-based virtual screening on an in house database, dual MDM2/MDM4 binders. Compound 1 turned out to possess an IC50 of 93.7 and of 4.6 nM on MDM2 and MDM4, respectively. A series of compounds were synthesized to optimize its activity on MDM2. As a result, compound 12 showed low nanomolar IC50 for both targets. NMR studies confirmed the pocket of binding of 12 as predicted by the Glide docking software. Notably, 12 was able to cause concentration-dependent inhibition of cell proliferation, yielding an IC50 value of 356 ± 21 nM in neuroblastoma SHSY5Y cells and proved even to efficiently block cancer stem cell growth. The function of p53 protein, also known as "genome guardian", might be impaired by the overexpression of its primary cellular inhibitor, the murine double minute 2 protein (MDM2). However, the recent finding that MDM2-selective inhibitors induce high levels of its homologue MDM4, prompt us to identify, through a receptor-based virtual screening on an in house database, dual MDM2/MDM4 binders. Compound 1 turned out to possess an IC50 of 93.7 and of 4.6 nM on MDM2 and MDM4, respectively. A series of compounds were synthesized to optimize its activity on MDM2. As a result, compound 12 showed low nanomolar IC50 for both targets. NMR studies confirmed the pocket of binding of 12 as predicted by the Glide docking software. Notably, 12 was able to cause concentration-dependent inhibition of cell proliferation, yielding an IC50 value of 356 ± 21 nM in neuroblastoma SHSY5Y cells and proved even to efficiently block cancer stem cell growth.

We synthesized 3-aroyl-1-arylpyrrole (ARAP) derivatives as potential anticancer agents having different substituents at the pendant 1-phenyl ring. Both the 1-phenyl ring and 3-(3,4,5-trimethoxyphenyl)carbonyl moieties were mandatory to achieve potent inhibition of tubulin polymerization, binding of colchicine to tubulin, and cancer cell growth. ARAP 22 showed strong inhibition of the P-glycoprotein-overexpressing NCI-ADR-RES and Messa/Dx5MDR cell lines. Compounds 22 and 27 suppressed in vitro the Hedgehog signaling pathway, strongly reducing luciferase activity in SAG treated NIH3T3 Shh-Light II cells, and inhibited the growth of medulloblastoma D283 cells at nanomolar concentrations. ARAPs 22 and 27 represent a new potent class of tubulin polymerization and cancer cell growth inhibitors with the potential to inhibit the Hedgehog signaling pathway.

Indoleamine 2,3-dioxygenase 1 (IDO1) is an attractive target for anticancer therapy. Herein, we report a virtual screening study which led to the identification of compound 5 as a new IDO1 inhibitor. In order to improve the biological activity of the identified hit, arylthioindoles 6–30 were synthesized and tested. Among these, derivative 21 exhibited an IC50 value of 7 μM, being the most active compound of the series. Furthermore, compounds 5 and 21 induced a dose-dependent growth inhibition in IDO1 expressing cancer cell lines HTC116 and HT29. Three-dimensional quantitative structure–activity relationship studies were carried out in order to rationalize obtained results and suggest new chemical modifications.

New indolylarylsulfone derivatives bearing cyclic substituents at indole-2-carboxamide linked through a methylene/ethylene spacer were potent inhibitors of the WT HIV-1 replication in CEM and PBMC cells with inhibitory concentrations in the low nanomolar range. Against the mutant L100I and K103N RT HIV-1 strains in MT-4 cells, compounds 20, 24-26, 36, and 40 showed antiviral potency superior to that of NVP and EFV. Against these mutant strains, derivatives 20, 24-26, and 40 were equipotent to ETV. Molecular docking experiments on this novel series of IAS analogues have also suggested that the H-bond interaction between the nitrogen atom in the carboxamide chain of IAS and Glu138:B is important in the binding of these compounds. These results are in accordance with the experimental data obtained on the WT and on the mutant HIV-1 strains tested.

Indolyl aryl sulfone (IAS) non-nucleoside reverse transcriptase (RT) inhibitors (NNRTIs) have been previously shown to effectively inhibit wild-type (wt) and drug-resistant human immunodeficiency virus type 1 (HIV-1) replication. IASs proved to act through different mechanisms of action, depending on the nature and position of their chemical substituents. Here we describe selected novel IAS derivatives (di-halo-IASs). Our results show that these compounds are selective for the enzyme-substrate complex. The molecular basis for this selectivity was a different dissociation rate of the drug to a particular enzymatic form along the reaction pathway. By comparing the activities of the different compounds against wild-type RT and the resistant enzymes carrying the single mutations Lys103Asn, Leu100Ile, and Tyr181Ile (K103N, L100I, and Y181I), we found that one compound (RS1914) dissociated from the mutated enzymes almost 10-fold slower than from the wild type RT. These results demonstrate that IASs are very flexible molecules, interacting dynamically with the viral RT, and that this property can be successfully exploited to design inhibitors endowed with an enhanced binding to common NNRTI-resistant mutants.

We describe the characterisation of a series of 4,4'-biphenylsulfonamides as selective inhibitors of matrix metalloproteases MMP-2 and -13, two enzymes involved in cell invasion and angiogenesis. Double-inhibitor studies in the presence of acetohydroxamic acid show that these molecules do not bind the catalytic zinc. Moreover, two of the characterised inhibitors (11 and 19) act as non-competitive inhibitors, whereas the para-methyl ester derivative 13 behaves as a competitive inhibitor. This finding suggests that this class of molecules binds to a catalytic subsite, possibly the S1'-pocket. Moreover, since these compounds also act as inhibitors of carbonic anhydrases (CAs), another family of enzymes involved in cell invasion, they could be potentially useful as CA/MMP dual target inhibitors with increased efficacy as anticancer agents.

Arylthioindoles (ATIs) that possess a 3-methoxyphenylthio or a 3,5-dimethoxyphenylthio moiety at position 2 of the indole ring were effective tubulin assembly inhibitors, but weak inhibitors of MCF-7 cell growth. ATIs bearing a 3-(3,4,5-trimethoxyphenyl)thio moiety were potent tubulin polymerization inhibitors, with IC(50)s in the 2.0 (35) to 4.5 (37) microM range. They also inhibited MCF-7 cell growth at nanomolar concentrations. The 3,4,5-trimethoxy substituted ATIs showed potencies comparable to those of the reference compounds colchicine and combretastatin A-4 in both tubulin assembly and cell growth inhibition assays. Dynamics simulation studies correlate well with the observed experimental data. Furthermore, from careful analysis of the biological and in silico data, we can now hypothesize a basic pharmacophore for this class of compounds.

Cell cycle experiments with our previously reported 4-biphenylaminoquinazoline (1–3) multityrosine kinase inhibitors revealed an activity profile resembling that of known tubulin polymerization inhibitors. Novel 4-biarylaminoquinazoline analogues of compound 2 were synthesized and evaluated as inhibitors of several tyrosine kinases and of tubulin. Although compounds 1–3 acted as dual inhibitors, the heterobiaryl analogues possessed only anti-tubulin properties and targeted the colchicine site. Furthermore, molecular modeling studies allowed the rationalization of the pharmacodynamic properties of the compounds.

Background Histone demethylases (HDMs) have a prominent role in epigenetic regulation and are emerging as potential therapeutic cancer targets. The search for small molecules able to inhibit HDMs in vivo is very active but at the present few compounds were found to be specific for defined classes of these enzymes. Methodology/Principal Findings In order to discover inhibitors specific for H3K4 histone demethylation we set up a screening system which tests the effects of candidate small molecule inhibitors on a S.cerevisiae strain which requires Jhd2 demethylase activity to efficiently grow in the presence of rapamycin. In order to validate the system we screened a library of 45 structurally different compounds designed as competitive inhibitors of α -ketoglutarate (α-KG) cofactor of the enzyme, and found that one of them inhibited Jhd2 activity in vitro and in vivo. The same compound effectively inhibits human Jumonji AT-Rich Interactive Domain (JARID) 1B and 1D in vitro and increases H3K4 tri-methylation in HeLa cell nuclear extracts (NEs). When added in vivo to HeLa cells, the compound leads to an increase of tri-methyl-H3K4 (H3K4me3) but does not affect H3K9 tri-methylation. We describe the cytostatic and toxic effects of the compound on HeLa cells at concentrations compatible with its inhibitory activity. Conclusions/Significance Our screening system is proved to be very useful in testing putative H3K4-specific HDM inhibitors for the capacity of acting in vivo without significantly altering the activity of other important 2-oxoglutarate oxygenases.

New arylthioindole derivatives having different cyclic substituents at position 2 of the indole were synthesized as anticancer agents. Several compounds inhibited tubulin polymerization at submicromolar concentration and inhibited cell growth at low nanomolar concentrations. Compounds 18 and 57 were superior to the previously synthesized 5. Compound 18 was exceptionally potent as an inhibitor of cell growth: it showed IC50 = 1.0 nM in MCF-7 cells, and it was uniformly active in the whole panel of cancer cells and superior to colchicine and combretastatin A-4. Compounds 18, 20, 55, and 57 were notably more potent than vinorelbine, vinblastine, and paclitaxel in the NCI/ADR-RES and Messa/Dx5 cell lines, which overexpress P-glycoprotein. Compounds 18 and 57 showed initial vascular disrupting effects in a tumor model of liver rhabdomyosarcomas at 15 mg/kg intravenous dosage. Derivative 18 showed water solubility and higher metabolic stability than 5 in human liver microsomes.

In recent years, epidemiological and biochemical studies have shown that eating apples is associated with reduction of occurrence of cancer, degenerative, and cardiovascular diseases. This association is often attributed to the presence of antioxidants such as ascorbic acid (vitamin C) and polyphenols. The substances that hinder the presence of free radicals are also able to protect cells from aging. In our laboratory we used yeast, a unicellular eukaryotic organism, to determinein vivoefficacy of entire apples and their components, such as flesh, skin and polyphenolic fraction, to influence aging and oxidative stress. Our results indicate that all the apple components increase lifespan, with the best result given by the whole fruit, indicating a cooperative role of all apple components.

New indolylarylsulfone (IAS) derivatives bearing nitrogen containing substituents at the indole-2-carboxamide inhibited the HIV-1 WT in MT-4 cells at low nanomolar concentrations. In particular, compound 9 was uniformly effective against the mutant Y181C, Y188L, and K103N HIV-1 strains; it was highly active against the multidrug resistant mutant IRLL98 HIV-1 strain bearing the K101Q, Y181C, and G190A mutations conferring resistance to NVP, DLV, and EFV and several HIV-1 clades A in PBMC. © 2012 American Chemical Society.

New arylthioindoles (ATIs) were obtained by replacing the 2-alkoxycarbonyl group with a bioisosteric 5-membered heterocycle nucleus. The new ATIs 5, 8, and 10 inhibited tubulin polymerization, reduced cell growth of a panel of human transformed cell lines, and showed higher metabolic stability than the reference ester 3. These compounds induced mitotic arrest and apoptosis at a similar level as combretastatin A-4 and vinblastine and triggered caspase-3 expression in a significant fraction of cells in both p53-proficient and p53-defective cell lines. Importantly, ATIs 5, 8, and 10 were more effective than vinorelbine, vinblastine, and paclitaxel as growth inhibitors of the P-glycoprotein-overexpressing cell line NCI/ADR-RES. Compound 5 was shown to have medium metabolic stability in both human and mouse liver microsomes, in contrast to the rapidly degraded reference ester 3, and a pharmacokinetic profile in the mouse characterized by a low systemic clearance and excellent oral bioavailability.

New arylthioindoles along with the corresponding ketone and methylene compounds were potent tubulin assembly inhibitors. As growth inhibitors of MCF-7 cells, sulfur derivatives were superior or sometimes equivalent to the ketones, while methylene derivatives were substantially less effective. Esters 24, 27-29, 36, 39, and 41 showed approximately 50% of inhibition on human HeLa and HCT116/chr3 cells at 0.5 microM, and these compounds inhibited the growth of HEK, M14, and U937 cells with IC(50)'s in the 78-220 nM range. While murine macrophage J744.1 cell growth was significantly less affected (20% at higher concentrations), four other nontransformed cell lines remained sensitive to these esters. The effect of drug treatment on cell morphology was examined by time-lapse microscopy. In a protocol set up to evaluate toxicity on the Saccharomyces cerevisiae BY4741 wild type strain, compounds 24 and 54 strongly reduced cell growth, and 29, 36, and 39 also showed significant inhibition.

Introduction Since MAO-A is an enzyme involved in the metabolism of neurotransmitters, fluctuations in MAO-A functionality are associated with psychiatric and neurological disorders as well as with tobacco addiction and behaviour. This study reports the radiolabelling of two [ 11 C]-labelled pyrrole-2-carboxamide derivates, RS 2315 and RS 2360, along with the characterization of their in vivo properties. Methods The radiolabelling of [ 11 C]-RS 2315 and [ 11 C]-RS 2360 was accomplished by alkylation of their amide precursors with [ 11 C]CH 3 I. Biodistribution, blocking and metabolite studies of both tracers were performed in NMRI mice. Finally, a PET study in Sprague-Dawley rats was performed for [ 11 C]-RS 2360. Results Both tracers were obtained in a radiochemical yield of approximately 30% with radiochemical purity of >98%. Biodistribution studies showed high brain uptake followed by rapid brain clearance for both radiotracers. In the brain, [ 11 C]-RS 2360 was more stable than [ 11 C]-RS 2315. Blocking studies in mice could not demonstrate specificity of [ 11 C]-RS 2315 towards MAO-A or MAO-B. The blocking and imaging study with [ 11 C]-RS 2360 on the other hand indicated specific binding in MAO-A at the earliest time points. Conclusions [ 11 C]-RS 2315 displayed a high nonspecific binding and is therefore not suitable for visualization of MAO-A in vivo. [ 11 C]-RS 2360 on the other hand has potential for mapping MAO-A since specific binding is demonstrated.

Drug resistance of cancer cells is often correlated with the evasion of apoptosis, thus a major goal in cancer research is to search for compounds able to counteract cancer by promoting apoptosis. A variety of compounds with anticancer activity are characterised by the presence of the pyrazole as core nucleus. We synthesised a panel of pyrrolyl-pyrazole-carboxamides and we focused on the new compound RS 2780 (N-2-phenylethyl 1-(4-chlorophenyl)-3-methyl-5-pyrrolylpyrazole-4-carboxamide). The biological effects of RS 2780 on cell proliferation and viability were first evaluated on human HeLa cancer cells. As revealed by cell growth and viability experiments, a 24-h treatment of HeLa cells with increasing concentrations of RS 2780 (ranging from 0.1 to 100 microM) proved to inhibit cell proliferation and to affect cell viability. Notably, the new compound was effective also on colon carcinoma SW613-B3 cells, which are extremely resistant to most drugs, while it does not alter the proliferation of normal fibroblasts. We observed that RS 2780 interferes with the structural and functional properties of mitochondria, leading to the activation of the mitochondria-dependent apoptotic pathway. Apoptosis occurrence was supported by a number of morphological and biochemical hallmarks, including chromatin condensation, internucleosomal DNA fragmentation, PARP-1 cleavage and caspase activation. In conclusion, our results demonstrate for the first time the antiproliferative properties of the new compound RS 2780 on HeLa and SW613-B3 cancer cells and show that its effects on mitochondria lead to apoptosis.

New substituted 1-aryl-5-(1H-pyrrol-1-yl)-1H-pyrazole-3-carboxamides were synthesized by replacing the 2,4-dichlorobenzyl and cyclohexyl moieties at the 3-carboxamide nitrogen of the previously reported CB(1) receptor antagonists/inverse agonists 4 and 5. Several ligands showed potent affinity for the hCB(1) receptor, with K(i) concentrations comparable to the reference compounds 1, 4 and 5, and exhibited CB(1) selectivity comparable to 1 and 2. Docking experiments and molecular dynamics (MD) simulations explained the potent hCB(1) binding affinity of compounds 31 and 37. According to our previous studies, 31 and 37 formed a H-bond with K3.28(192), which accounted for the high affinity for the receptor inactive state and the inverse agonist activity. The finding of inhibition of food intake following their acute administration to rats, supported the concept that the CB(1) selective compounds 4 and 52 act as antagonists/inverse agonists.

New potent indolylarylsulfone (IAS) HIV-1 NNRTIs were obtained by coupling natural and unnatural amino acids to the 2-carboxamide and introducing different electron-withdrawing substituents at position 4 and 5 of the indole nucleus. The new IASs inhibited the HIV-1 replication in human T-lymphocyte (CEM) cells at low/subnanomolar concentration and were weakly cytostatic. Against the mutant L100I, K103N, and Y181C RT HIV-1 strains in CEM cells, sulfones 3, 4, 19, 27, and 31 were comparable to EFV. The new IASs were inhibitors to Coxsackie B4 virus at low micromolar (2-9 microM) concentrations. Superimposition of PLANTS docked conformations of IASs 19 and 9 revealed different hydrophobic interactions of the 3,5-dimethylphenyl group, for which a staking interaction with Tyr181 aromatic side chain was observed. The binding mode of 19 was not affected by the L100I mutation and was consistent with the interactions reported for the WT strain.

New monoamine oxidase inhibitors were synthesized as indole analogues of a previously reported pyrrole series. Several compounds were potent MAO-A (12, 17, 19-22, 31, 36, and 37) or MAO-B (14, 20, 24, 38, 44, and 46) inhibitors, and had K(i) values in the nanomolar concentration range. In particular, 22 (K(i)=0.00092 microM, and SI=68,478) was exceptionally potent and selective as MAO-A inhibitor. In molecular modeling studies, compounds 22, 24, 44, and 46 positioned the indole ring into an aromatic cavity of MAO-A, and established pi-pi stacking interactions with Tyr407, Tyr444, and FAD cofactor. However, only compound 22 was able to form hydrogen bonds with FAD, a finding which was in accordance with its potent anti-MAO-A activity. Conversely, 22/MAOB complex was highly unstable during the MD simulation.

New non-nucleoside reverse transcriptase inhibitors (NNRTIs) that are active against the commonly occurring mutations of HIV are urgently needed for the treatment of AIDS. We synthesized new NNRTIs of the indolyl aryl sulphone (IAS) family, which are endowed with high antiviral potency against HIV-1 wt (wild-type), and the Y181C and K103N-Y181C drug resistant mutant strains. Several new compounds were highly active in lymphocytes infected with primary isolates carrying the K103N-V108I-M184V and L100I-V108I mutations. The design of new IASs was based on three-dimensional quantitative structure-activity relationship (3D QSAR) studies and docking simulations. A cross-docking study was also undertaken to gain some insights in to the binding mode of the newly synthesized IASs in the wt and mutated isoforms of reverse transcriptase.

Indolyl aryl sulfone (IAS) nonnucleoside inhibitors have been shown to potently inhibit the growth of wild-type and drug-resistant human immunodeficiency virus type 1 (HIV-1), but their exact mechanism of action has not been elucidated yet. Here, we describe the mechanism of inhibition of HIV-1 reverse transcriptase (RT) by selected IAS derivatives. Our results showed that, depending on the substitutions introduced in the IAS common pharmacophore, these compounds can be made selective for different enzyme-substrate complexes. Moreover, we showed that the molecular basis for this selectivity was a different association rate of the drug to a particular enzymatic form along the reaction pathway. By comparing the activities of the different compounds against wild-type RT and the nonnucleoside reverse transcriptase inhibitor-resistant mutant Lys103Asn, it was possible to hypothesize, on the basis of their mechanism of action, a rationale for the design of drugs which could overcome the steric barrier imposed by the Lys103Asn mutation.