Oxidative stress changes interactions between 2 bacterial species from competitive to facilitative.

Knowing how species interact within microbial communities is crucial to predicting and controlling community dynamics, but interactions can depend on environmental conditions. The stress-gradient hypothesis (SGH) predicts that species are more likely to facilitate each other in harsher environments. Even if the SGH gives some intuition, quantitative modeling of the context-dependency of interactions requires understanding the mechanisms behind the SGH. In this study, we show with both experiments and a theoretical analysis that varying the concentration of a single compound, linoleic acid (LA), modifies the interaction between 2 bacterial species, Agrobacterium tumefaciens and Comamonas testosteroni, from competitive at a low concentration, to facilitative at higher concentrations where LA becomes toxic for one of the 2 species. We demonstrate that the mechanism behind facilitation is that one species is able to reduce reactive oxygen species (ROS) that are produced spontaneously at higher concentrations of LA, allowing for short-term rescue of the species that is sensitive to ROS and longer coexistence in serial transfers. In our system, competition and facilitation between species can occur simultaneously, and changing the concentration of a single compound can alter the balance between the two.

Deuterium in drug discovery: progress, opportunities and challenges.

Substitution of a hydrogen atom with its heavy isotope deuterium entails the addition of one neutron to a molecule. Despite being a subtle change, this structural modification, known as deuteration, may improve the pharmacokinetic and/or toxicity profile of drugs, potentially translating into improvements in efficacy and safety compared with the non-deuterated counterparts. Initially, efforts to exploit this potential primarily led to the development of deuterated analogues of marketed drugs through a 'deuterium switch' approach, such as deutetrabenazine, which became the first deuterated drug to receive FDA approval in 2017. In the past few years, the focus has shifted to applying deuteration in novel drug discovery, and the FDA approved the pioneering de novo deuterated drug deucravacitinib in 2022. In this Review, we highlight key milestones in the field of deuteration in drug discovery and development, emphasizing recent and instructive medicinal chemistry programmes and discussing the opportunities and hurdles for drug developers, as well as the questions that remain to be addressed.

Targeting the multifaceted neurotoxicity of Alzheimer's disease by tailored functionalisation of the curcumin scaffold.

Simultaneous modulation of multifaceted toxicity arising from neuroinflammation, oxidative stress, and mitochondrial dysfunction represents a valuable therapeutic strategy to tackle Alzheimer's disease. Among the significant hallmarks of the disorder, Aß protein and its aggregation products are well-recognised triggers of the neurotoxic cascade. In this study, by tailored modification of the curcumin-based lead compound 1, we aimed at developing a small library of hybrid compounds targeting Aß protein oligomerisation and the consequent neurotoxic events. Interestingly, from in vitro studies, analogues 3 and 4, bearing a substituted triazole moiety, emerged as multifunctional agents able to counteract Aß aggregation, neuroinflammation and oxidative stress. In vivo proof-of-concept evaluations, performed in a Drosophila oxidative stress model, allowed us to identify compound 4 as a promising lead candidate.

A Versatile and Sustainable Multicomponent Platform for the Synthesis of Protein Degraders: Proof-of-Concept Application to BRD4-Degrading PROTACs.

The use of small molecules to induce targeted protein degradation is increasingly growing in the drug discovery landscape, and protein degraders have progressed rapidly through the pipelines. Despite the advances made so far, their synthesis still represents a significant burden and new approaches are highly demanded. Herein we report an unprecedented platform that leverages the modular nature of both multicomponent reactions and degraders to enable the preparation of highly decorated PROTACs. As a proof of principle, our platform has been applied to the preparation of potential BRD4-degrading PROTACs, resulting in the discovery of a set of degraders endowed with high degradation efficiency. Compared to the existing methods, our approach offers a versatile and cost-effective means to access libraries of protein degraders and increase the chance of identifying successful candidates.

Classifying Interactions in a Synthetic Bacterial Community Is Hindered by Inhibitory Growth Medium.

Predicting the fate of a microbial community and its member species relies on understanding the nature of their interactions. However, designing simple assays that distinguish between interaction types can be challenging. Here, we performed spent medium assays based on the predictions of a mathematical model to decipher the interactions among four bacterial species: Agrobacterium tumefaciens, Comamonas testosteroni, Microbacterium saperdae, and Ochrobactrum anthropi. While most experimental results matched model predictions, the behavior of C. testosteroni did not: its lag phase was reduced in the pure spent media of A. tumefaciens and M. saperdae but prolonged again when we replenished our growth medium. Further experiments showed that the growth medium actually delayed the growth of C. testosteroni, leading us to suspect that A. tumefaciens and M. saperdae could alleviate this inhibitory effect. There was, however, no evidence supporting such "cross-detoxification," and instead, we identified metabolites secreted by A. tumefaciens and M. saperdae that were then consumed or "cross-fed" by C. testosteroni, shortening its lag phase. Our results highlight that even simple, defined growth media can have inhibitory effects on some species and that such negative effects need to be included in our models. Based on this, we present new guidelines to correctly distinguish between different interaction types such as cross-detoxification and cross-feeding. IMPORTANCE Communities of microbes colonize virtually every place on earth. Ultimately, we strive to predict and control how these communities behave, for example, if they reside in our guts and make us sick. But precise control is impossible unless we can identify exactly how their member species interact with one another. To find a systematic way to measure interactions, we started very simply with a small community of four bacterial species and carefully designed experiments based on a mathematical model. This first attempt accurately mapped out interactions for all species except one. By digging deeper, we understood that our method failed for that species as it was suffering in the growth medium that we chose. A revised model that considered that growth media can be harmful could then make more accurate predictions. What we have learned with these four species can now be applied to decipher interactions in larger communities.

Novel fragment-derived colchicine-site binders as microtubule-destabilizing agents.

Microtubules (MTs) are dynamic filaments of the cytoskeleton, which are formed by the polymerization of their building block tubulin. Perturbation of MT dynamics by MT-targeting agents (MTAs) leads to cell cycle arrest or cell death, a strategy that is pursued in chemotherapy. We recently performed a combined computational and crystallographic fragment screening approach and identified several tubulin-binding fragments. Here, we sought to capitalize on this study with the aim to demonstrate that low affinity tubulin-binding fragments can indeed be used as valuable starting points for the development of active, lead-like antitubulin small molecules. To this end, we report on a new, rationally designed series of 2-aminobenzimidazole derivatives that destabilize MTs by binding tubulin at the colchicine-binding site (CBS). We applied a fragment growing strategy by combining X-ray crystallography and computer-aided drug design. Preliminary structure-activity-relationship studies afforded compound 18 that inhibits HeLa cell viability with a submicromolar activity (IC50 of 0.9 µM). X-ray crystallography confirmed the compound pose in the CBS, while immunostaining experiments suggested a molecular mechanism of action alike classical CBS ligands with antimitotic and antitumor activity associated with MTs destabilization. This promising outcome underpins that our previously performed combined computational and crystallographic fragment screening approach provides promising starting points for developing new MTAs binding to the CBS of tubulin and, eventually, to further tubulin pockets.

The multitarget FAAH inhibitor/D3 partial agonist ARN15381 decreases nicotine self-administration in male rats.

Tobacco use disorder is a worldwide health problem for which available medications show limited efficacy. Nicotine is the psychoactive component of tobacco responsible for its addictive liability. Similar to other addictive drugs, nicotine enhances mesolimbic dopamine transmission. Inhibition of the fatty acid amide hydrolase (FAAH), the enzyme responsible for the degradation of the endocannabinoid anandamide (AEA), palmitoylethanolamide (PEA) and oleoylethanolamide (OEA), reduces nicotine-enhanced dopamine transmission and acquisition of nicotine self-administration in rats. Down-regulation of dopamine transmission by antagonists or partial agonists of the dopamine D3 receptor (DRD3) also reduced nicotine self-administration and conditioned place preference. Based on these premises, we evaluated the effect of ARN15381, a multitarget compound showing FAAH inhibition and DRD3 partial agonist activity in the low nanomolar range, on nicotine self-administration in rats. Pretreatment with ARN15381 dose dependently decreased self-administration of a nicotine dose at the top of the nicotine dose/response (D/R) curve, while it did not affect self-administration of a nicotine dose laying on the descending limb of the D/R curve. Conversely, pretreatment with the selective FAAH inhibitor URB597 and the DRD3 partial agonist CJB090 failed to modify nicotine self-administration independent of the nicotine dose self-administered. Our data indicates that the concomitant FAAH inhibition and DRD3 partial agonism produced by ARN15381 is key to the observed reduction of nicotine self-administration, demonstrating that a multitarget approach may hold clinical importance for the treatment of tobacco use disorder.

Modulation of Amyloid ß-Induced Microglia Activation and Neuronal Cell Death by Curcumin and Analogues.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that is not restricted to the neuronal compartment but includes important interactions with immune cells, including microglia. Protein aggregates, common pathological hallmarks of AD, bind to pattern recognition receptors on microglia and trigger an inflammatory response, which contributes to disease progression and severity. In this context, curcumin is emerging as a potential drug candidate able to affect multiple key pathways implicated in AD, including neuroinflammation. Therefore, we studied the effect of curcumin and its structurally related analogues cur6 and cur16 on amyloid-ß (Aß)-induced microglia activation and neuronal cell death, as well as their effect on the modulation of Aß aggregation. Primary cortical microglia and neurons were exposed to two different populations of Aß42 oligomers (Aß42Os) where the oligomeric state had been assigned by capillary electrophoresis and ultrafiltration. When stimulated with high molecular weight Aß42Os, microglia released proinflammatory cytokines that led to early neuronal cell death. The studied compounds exerted an anti-inflammatory effect on high molecular weight Aß42O-stimulated microglia and possibly inhibited microglia-mediated neuronal cell toxicity. Furthermore, the tested compounds demonstrated antioligomeric activity during the process of in vitro Aß42 aggregation. These findings could be investigated further and used for the optimization of multipotent candidate molecules for AD treatment.

Dopamine D3 receptor ligands: a patent review (2014-2020).

INTRODUCTION: Compelling evidence identified D3 dopamine receptor (D3R) as a suitable target for therapeutic intervention on CNS-associated disorders, cancer, and other conditions. Several efforts have been made toward developing potent and selective ligands for modulating signaling pathways operated by these GPCRs. The rational design of D3R ligands endowed with a pharmacologically relevant profile has traditionally not encountered much support from computational methods due to a very limited knowledge of the receptor structure and of its conformational dynamics. Recent progress in structural biology will change this state of affairs in the next decade. AREAS COVERED: This review provides an overview of the recent (2014-2020) patent literature on novel classes of D3R ligands developed within the framework of CNS-related diseases, cancer, and additional conditions. When possible, an in-depth description of both in vitro and in vivo generated data is presented. New therapeutic applications of known molecules with activity at D3R are discussed. EXPERT OPINION: Building on current knowledge, future D3R-focused drug discovery campaigns will be propelled by a combination of unprecedented availability of structural information with advanced computational and analytical methods. The design of D3R ligands with the sought activity, efficacy, and selectivity profile will become increasingly more streamlined.

ARN25068, a versatile starting point towards triple GSK-3ß/FYN/DYRK1A inhibitors to tackle tau-related neurological disorders.

The human kinome plays a crucial role in several pathways. Its dysregulation has been linked to diverse central nervous system (CNS)-related disorders with a drastic impact on the aging population. Among them, tauopathies, such as Alzheimer's Disease (AD) and Frontotemporal Lobar degeneration (FTLD-tau), are neurodegenerative disorders pathologically defined by the presence of hyperphosphorylated tau-positive intracellular inclusions known as neurofibrillary tangles (NFTs). Compelling evidence has reported the great potential of the simultaneous modulation of multiple protein kinases (PKs) involved in abnormal tau phosphorylation through a concerted pharmacological approach to achieve a superior therapeutic effect relative to classic "one target, one drug" approaches. Here, we report on the identification and characterization of ARN25068 (4), a low nanomolar and well-balanced dual GSK-3ß and FYN inhibitor, which also shows inhibitory activity against DYRK1A, an emerging target in AD and tauopathies. Computational and X-Ray studies highlight compound 4's typical H-bonding pattern of ATP-competitive inhibitors at the binding sites of all three PKs. In a tau phosphorylation assay on Tau0N4R-TM-tGFP U2OS cell line, 4 reduces the extent of tau phosphorylation, promoting tau-stabilized microtubule bundles. In conclusion, this compound emerges as a promising prototype for further SAR explorations to develop potent and well-balanced triple GSK-3ß/FYN/DYRK1A inhibitors to tackle tau hyperphosphorylation.

GSK-3ß, FYN, and DYRK1A: Master Regulators in Neurodegenerative Pathways.

Protein kinases (PKs) have been recognized as central nervous system (CNS)-disease-relevant targets due to their master regulatory role in different signal transduction cascades in the neuroscience space. Among them, GSK-3ß, FYN, and DYRK1A play a crucial role in the neurodegeneration context, and the deregulation of all three PKs has been linked to different CNS disorders with unmet medical needs, including Alzheimer's disease (AD), Parkinson's disease (PD), frontotemporal lobar degeneration (FTLD), and several neuromuscular disorders. The multifactorial nature of these diseases, along with the failure of many advanced CNS clinical trials, and the lengthy approval process of a novel CNS drug have strongly limited the CNS drug discovery. However, in the near-decade from 2010 to 2020, several computer-assisted drug design strategies have been combined with synthetic efforts to develop potent and selective GSK-3ß, FYN, and DYRK1A inhibitors as disease-modifying agents. In this review, we described both structural and functional aspects of GSK-3ß, FYN, and DYRK1A and their involvement and crosstalk in different CNS pathological signaling pathways. Moreover, we outlined attractive medicinal chemistry approaches including multi-target drug design strategies applied to overcome some limitations of known PKs inhibitors and discover improved modulators with suitable blood-brain barrier (BBB) permeability and drug-like properties.

Curcumin-1,2,3-Triazole Conjugation for Targeting the Cancer Apoptosis Machinery.

The burden of neoplastic diseases is widely recognized as a severe cause of mortality. The clinical inadequacy of most anticancer therapeutics urgently prompted intense drug discovery efforts toward the identification of new chemical entities endowed with a potent and safe antitumor profile. In this scenario, targeting cancer cells apoptosis machinery has emerged as a relevant strategy, useful for tackling the emergence of drug resistance. On this basis, a small library of naturally inspired hybrid molecules was obtained by combining, through a click chemistry approach, "privileged" synthons such as curcumin scaffold and 1,2,3-triazole building block. Compound 1, bearing a para-fluoro phenyl moiety, showed low-micromolar potency against T acute lymphoblastic leukemia cell growth. More in-depth biologic studies demonstrated, for this analog, cell death-inducing properties associated with its capability to simultaneously activate both the receptor and the mitochondrial apoptosis cascades. This peculiar behavior offers promises for achieving an expanded anticancer effect, namely intense cytotoxic response coupled with reduced predisposition of chemoresistance insurgence. Altogether, this study allowed the identification of compound 1 as a lead compound worth to be progressed as an anticancer drug candidate.

Novel Curcumin-Diethyl Fumarate Hybrid as a Dualistic GSK-3ß Inhibitor/Nrf2 Inducer for the Treatment of Parkinson's Disease.

Common copathogenic factors, including oxidative stress and neuroinflammation, are found to play a vital role in the development of neurodegenerative disorders, including Alzheimer's disease (AD) and Parkinson's disease (PD). Nowadays, owing to the multifactorial character of the diseases, no effective therapies are available, thus underlying the need for new strategies. Overexpression of the enzyme GSK-3ß and downregulation of the Nrf2/ARE pathway are responsible for a decrease in antioxidant defense effects. These pieces of evidence underline the usefulness of dual GSK-3ß inhibitors/Nrf2 inducers. In this regard, to design a dual modulator, the structures of a curcumin-based analogue, as GSK-3ß inhibitor, and a diethyl fumarate fragment, as Nrf2 inducer, were combined. Among the hybrids, 5 and 6 proved to effectively inhibit GSK-3ß, while 4 and 5 showed a marked ability to activate Nrf2 together to increase the neuronal resistance to oxidative stress. These last pieces of evidence translated into specific neuroprotective effects of 4 and 5 against PD pathological events including neurotoxicity elicited by α-synuclein aggregates and 6-hydroxydopamine. Hybrid 5 also showed neuroprotective effects in a C. elegans model of PD where the activation of GSK-3ß is intimately involved in Nrf2 regulation. In summary, 5 emerged as an interesting multitarget derivative, valuable to be exploited in a multitarget PD perspective.

Multitarget Compounds for Bipolar Disorder: From Rational Design to Preliminary Pharmacokinetic Evaluation.

Due to the complex and multifactorial nature of bipolar disorder (BD), single-target drugs have traditionally provided limited relief with no disease-modifying effects. In line with the polypharmacology paradigm, we attempted to overcome these limitations by devising two series of multitarget-directed ligands endowed with both a partial agonist profile at dopamine receptor D3 (D3R) and inhibitory activity against glycogen synthase kinase 3 beta (GSK-3ß). These are two structurally unrelated targets that play independent, yet connected, roles in cognition and mood regulation. Two compounds (7 and 10) emerged as promising D3R/GSK-3ß multitarget-directed ligands with nanomolar activity at D3R and low-micromolar inhibition of GSK-3ß, thereby confirming, albeit preliminarily, the feasibility of our strategy. Furthermore, 7 showed promising drug-like properties in stability and pharmacokinetic studies.

Investigating Drug-Target Residence Time in Kinases through Enhanced Sampling Simulations.

It is widely accepted that drug-target association and dissociation rates directly affect drug efficacy and safety. To rationally optimize drug binding kinetics, one must know the atomic arrangement of the protein-ligand complex during the binding/unbinding process in order to detect stable and metastable states. Whereas experimental approaches can determine kinetic constants with fairly good accuracy, computational approaches based on molecular dynamics (MD) simulations can deliver the atomistic details of the unbinding process. Furthermore, they can also be utilized prospectively to predict residence time (i.e., the inverse of unbinding kinetics constant, koff) with an acceptable level of accuracy. Here, we report a novel method based on adiabatic bias MD with an electrostatics-like collective variable (dubbed elABMD) for sampling protein-ligand dissociation events in two kinases. elABMD correctly ranked a ligand series on glucokinase, in agreement with experimental data and previous calculations. Subsequently, we applied the new method prospectively to a congeneric series of GSK-3ß inhibitors. For this series, new crystal structures were generated and the residence time was experimentally measured with surface plasmon resonance (SPR). There was good agreement between computational predictions and experimental measures, suggesting that elABMD is an innovative and efficient tool for calculating residence times.

Identification of chalcone-based antileishmanial agents targeting trypanothione reductase.

All currently used first-line and second-line drugs for the treatment of leishmaniasis exhibit several drawbacks including toxicity, high costs and route of administration. Furthermore, some drugs are associated with the emergence of drug resistance. Thus, the development of new treatments for leishmaniasis is a priority in the field of neglected tropical diseases. The present work highlights the use of natural derived products, i.e. chalcones, as potential source of antileishmanial agents. Thirty-one novel chalcone compounds have been synthesized and their activity has been evaluated against promastigotes of Leishmania donovani; 16 compounds resulted active against L. donovani in a range from 3.0 to 21.5 µM, showing low toxicity against mammalian cells. Among these molecules, 6 and 16 showed good inhibitory activity on both promastigotes and intracellular amastigotes, coupled with an high selectivity index. Furthermore, compounds 6 and 16 inhibited the promastigote growth of other leishmanial species, including L. tropica, L. major and L. infantum. Finally, 6 and 16 interacted with high affinity with trypanothione reductase (TR), an essential enzyme for the leishmanial parasite and compound 6 inhibited TR with sub-micromolar potency. Thus, the effective inhibitory activity against Leishmania, the lack of toxicity on mammalian cells and the ability to block a crucial parasite's enzyme, highlight the potential for compound 6 to be optimized as novel drug candidate against leishmaniasis.

Recent progress on curcumin-based therapeutics: a patent review (2012-2016). Part II: curcumin derivatives in cancer and neurodegeneration.

INTRODUCTION: Curcumin, the main bioactive compound found in the rhizome of Curcuma longa L., is considered a 'privileged structure', due to its ability to modulate different signaling pathways involved in the pathogenesis of several diseases. Unfortunately, its poor pharmacodynamic and pharmacokinetic properties, mainly related to chemical instability, low solubility and rapid metabolism, greatly reduce its therapeutic potential. In the last years a number of derivatives were developed and patented, aimed both at improving its multifaceted biological profile and overcoming its undesired effects. Areas covered: This review summarizes the patent literature of the last five years dealing with synthetic curcumin-related compounds in cancer and neurodegeneration, properly designed in order to avoid the so-called 'dark side of curcumin', and to take advantage of the beneficial properties of this molecule, worth to be further exploited to obtain effective therapeutics. Expert opinion: Due to the synergistic binding to several networked targets, curcumin turned out to be suitable for polypharmacological approaches, and its 'privileged structure' could also provide the key scaffold to develop novel multipotent drugs useful for treating multifactiorial pathologic conditions such as cancer and neurodegeneration.

Phenolic 1,3-diketones attenuate lipopolysaccharide-induced inflammatory response by an alternative magnesium-mediated mechanism.

BACKGROUND AND PURPOSE: Toll-like receptor 4 (TLR4) plays a key role in the induction of inflammatory responses both in peripheral organs and the CNS. Curcumin exerts anti-inflammatory functions by interfering with LPS-induced dimerization of TLR4-myeloid differentiation protein-2 (MD-2) complex and suppressing pro-inflammatory mediator release. However, the inhibitory mechanism of curcumin remains to be defined. EXPERIMENTAL APPROACH: Binding of bis-demethoxycurcumin (GG6) and its cyclized pyrazole analogue (GG9), lacking the 1,3-dicarbonyl function, to TLR4-MD-2 was determined using molecular docking simulations. The effects of these compounds on cytokine release and NF-κB activation were examined by ELISA and fluorescence staining in LPS-stimulated primary microglia. Interference with TLR4 dimerization was assessed by immunoprecipitation in Ba/F3 cells. KEY RESULTS: Both curcumin analogues bound to the hydrophobic region of the MD-2 pocket. However, only curcumin and GG6, both possessing the 1,3-diketone moiety, inhibited LPS-induced TLR4 dimerization, activation of NF-κB and secretion of pro-inflammatory cytokines in primary microglia. Consistent with the ability of 1,3-diketones to coordinate divalent metal ions, LPS stimulation in a low magnesium environment decreased pro-inflammatory cytokine release and NF-κB p65 nuclear translocation in microglia and decreased TLR4-MD-2 dimerization in Ba/F3 cells. Curcumin and GG6 also significantly reduced cytokine output in contrast to the pyrazole analogue GG9. CONCLUSIONS AND IMPLICATIONS: These results indicate that phenolic 1,3-diketones, with a structural motif able to coordinate magnesium ions, can modulate LPS-mediated TLR4-MD-2 signalling. Taken together, these studies identify a previously uncharacterized mechanism involving magnesium, underlying the inflammatory responses to LPS.

Design, Synthesis, Structure-Activity Relationship Studies, and Three-Dimensional Quantitative Structure-Activity Relationship (3D-QSAR) Modeling of a Series of O-Biphenyl Carbamates as Dual Modulators of Dopamine D3 Receptor and Fatty Acid Amide Hydrolase.

We recently reported molecules designed according to the multitarget-directed ligand paradigm to exert combined activity at human fatty acid amide hydrolase (FAAH) and dopamine receptor subtype D3 (D3R). Both targets are relevant for tackling several types of addiction (most notably nicotine addiction) and other compulsive behaviors. Here, we report an SAR exploration of a series of biphenyl-N-[4-[4-(2,3-substituted-phenyl)piperazine-1-yl]alkyl]carbamates, a novel class of molecules that had shown promising activities at the FAAH-D3R target combination in preliminary studies. We have rationalized the structural features conducive to activities at the main targets and investigated activities at two off-targets: dopamine receptor subtype D2 and endocannabinoid receptor CB1. To understand the unexpected affinity for the CB1 receptor, we devised a 3D-QSAR model, which we then prospectively validated. Compound 33 was selected for PK studies because it displayed balanced affinities for the main targets and clear selectivity over the two off-targets. 33 has good stability and oral bioavailability and can cross the blood-brain barrier.

Coumarin derivatives as potential antitumor agents: Growth inhibition, apoptosis induction and multidrug resistance reverting activity.

A small library of coumarins, carrying butynyl-amino chains, was synthesized continuing our studies in the field of MDR reverting ageEnts and in order to obtain multipotent agents to combat malignancies. In particular, the reported anticancer and chemopreventive natural product 7-isopentenyloxycoumarin was linked to different terminal amines, selected on the basis of our previously reported results. The anticancer behaviour and the MDR reverting ability of the new compounds were evaluated on human colon cancer cells, particularly prone to develop the MDR phenotype. Some of the new derivatives showed promising effects, directly acting as cytotoxic compounds and/or counteracting MDR phenomenon. Compound 1e emerged as the most interesting of this series, showing a multipotent biological profile and suggesting that conjugation of an appropriate coumarin core with a properly selected butynyl-amino chain allows to obtain novel hybrid molecules endowed with improved in vitro antitumor activity.