Protonophores are small molecules that facilitate proton transport across lipid bilayers leading to a wide range of therapeutic and research applications. We report the design, synthesis, and biological evaluation of a new class of clickaccessible protonophores based on the 2-triazolylphenol scaffold. The 1,2,3-triazolyl motif acts as an amide isostere and promotes intramolecular hydrogen-bonding interactions that facilitate transmembrane transport of both protonated and deprotonated species. A focused library of derivatives was prepared through copper-catalysed azide–alkyne cycloaddition and characterised by spectroscopic, solution, and solid-state methods. Transmembrane proton transport assays in synthetic vesicles identified several highly active compounds, with the most potent derivatives displaying activities comparable to well-established salicylamide protonophores, including niclosamide. Biological evaluation across a panel of pancreatic ductal adenocarcinoma (PDAC) cell lines confirmed cellular activity and demonstrated mitochondrial uncoupling in respiratory ASPC1 cells. 19 and 24, the most active derivatives identified, induced cytotoxicity across all explored cell lines with distinct cooperativity in respiratory phenotypes under normoxic conditions. The scaffold was further adapted to generate orthonitrobenzyl photocaged protonophores that were inactive in the dark but reactivated efficiently upon blue-light irradiation in liposomal membranes. These results establish 2-triazolylphenols as a synthetically versatile platform for the development of tunable protonophores with potential applications in mitochondrial chemical biology and anticancer therapeutics.

The morpholine scaffold constitutes a privileged structural motif in medicinal chemistry, although access to conformationally restricted systems remains challenging. Herein, we report a simple and efficient Ugi/postcondensation strategy that, for the first time, combines two aliphatic halogenated reagents with arylglyoxals to afford fused and bridged morpholines bearing ketal functionalities in a diastereoselective manner. These derivatives serve as precursors to 4-hydroxypyroglutamic acid derivatives, highlighting the synthetic versatility of the approach and providing rapid entry to structurally complex heterocyclic derivatives.

Herein we present a novel one‐pot methodology for the synthesis of enantioenriched 2 H ‐pyrrolespirosuccinimides by copper‐catalyzed reactions on Ugi adducts derived from enantiopure α‐alkylbenzyl amines through a chirality transfer process. We have proposed a mechanism, supported by density functional theory (DFT) calculations, where a hydrogen radical‐shuttle (HRS) process explains the chemical and stereochemical results. This work demonstrates the efficient stereoselective synthesis of structurally unique, highly functionalized nitrogen heterocyclic systems using simple protocols and affordable starting materials.

Novel 1,10-phenanthroline-2,9-bistriazoles derivatives have been synthesized by copper-catalyzed azide/alkyne cycloaddition reactions and assessed for their ability to bind and stabilize G-quadruplex (G4) structures. Ten novel compounds were evaluated using F & ouml;rster resonance energy transfer (FRET) melting, circular dichroism (CD), and fluorescence spectroscopy on several G4 sequences. Biophysical characterization led to the identification of compounds 4 a, 4 b, and 5 b as good G4 ligands of KRAS G4 sequences. The impact on cell viability of all derivatives was also assessed, revealing weak effects. However, compound 2 a exhibited cytotoxicity activity on A549 and H1299 cancer cells and low cytotoxicity towards MRC-5 non-malignant cells MRC-5 not connected with its G4-binding ability. Flow cytometry showed that 2 a induced a cell viability decrease in S and G2/M phases for A549 and H1299; thus, more studies should be performed to explore the proteins involved in cell cycle regulation.

The acidic microenvironment of solid tumors is a potential source of selectivity in the anti-cancer activity of ionophores, which requires delicate control of their biophysical properties. In this context, we have systematically studied fluorine substitutions in the aromatic side chains of HCl-binding pseudopeptidic cages. Interconnected factors like chloride binding, protonation, lipophilicity, and conformation and diffusiveness of the cages can impact their ability to transport HCl through the aqueous-lipid interphase, as demonstrated by robust experimental (X-ray, nuclear magnetic resonance [NMR], fluorescence) and theoretical results. The fine-tuning of these properties allows the modulation of their pH-dependent cytotoxicity against cancer cells, from essentially non-cytotoxic at pH 7.5 (like the extracellular surroundings of healthy tissues) to highly toxic in slightly acidic microenvironments (like those around solid tumors). Thus, a distal fluorine substitution produces a big impact on the physicochemical and biological properties of the cages, improving their selectivity as potential therapeutic ionophores.

Therapy resistance in human cancers is a major limitation in Clinical Oncology. In this regard, overexpression of anti-apoptotic proteins, such as survivin, has been described in several tumors, contributing to this clinical issue. Survivin has a dual role in key cellular functions, inducing cell cycle progression and inhibiting apoptosis; thus, survivin is an attractive target for cancer therapy. Therefore, we focused on identifying and validating a novel specific, directly binding survivin inhibitor for cancer treatment and tumor sensitization to conventional proapoptotic therapies. In this work, we conducted a structure-based high-throughput virtual screening at the survivin homodimerization domain. Asenapine Maleate (AM), an approved drug for central nervous system diseases, was identified as a direct binder of the survivin homodimerization domain and it significantly affected cell viability of lung, colon, and brain cancer cell lines. Direct interaction of AM to survivin protein was corroborated by surface plasmon resonance and a specific survivin protein decrease was observed in cancer cells, compared to other inhibitors of apoptosis proteins. Therapeutic in vivo studies showed an impairment of tumor growth in AM-treated mice. Finally, a synergistic anticancer effect was detected in vitro when combined with different conventional chemotherapies, and in vivo studies showed higher antitumor effects when combined with cisplatin. Altogether, our results identify AM as a specific direct binding inhibitor of survivin, showing anticancer properties in vitro and in vivo and sensitizing effects when combined with cisplatin, opening the possibility of repositioning this approved drug for cancer treatment.

Piperazines and diazepines are examples of nitrogen heterocycles present in many marketed drugs highlighting their importance in the discovery of novel bioactive compounds. However, their synthesis often faces challenges, including complex functionalization and lengthy reaction sequences. Multicomponent reactions, notably the Ugi reaction, have emerged as powerful tools to address these hurdles. Here, we have demonstrated the possibility of using the combination of arylglyoxals and carboxylic acids tethered to nonprotected deactivated amines as a powerful strategy for the synthesis of complex fused heterocycles. The limited nucleophilic character of the amino group of the anthranilic acid, indole-2-carboxylic acid, pyrrole-2-carboxylic acid or N-phenylglycine has allowed the use of these compounds in the Ugi reaction without triggering competitive reactions. The additional functional group present in the resulting Ugi adduct can be leveraged in different post-condensation strategies to easily generate multiple fused nitrogen heterocycles including benzodiazepinone and piperazinone cores.

Due to the relevance of lactic acidosis in cancer, several therapeutic strategies have been developed targeting its production and/or regulation. In this matter, inhibition approaches of key proteins such as lactate dehydrogenase or monocarboxylate transporters have showed promising results, however, metabolic plasticity and tumor heterogeneity limits their efficacy. In this study, we explored the anticancer potential of a new strategy based on disturbing lactate permeability independently of monocarboxylate transporters activity using a small molecule ionophore named Lactrans-1. Derived from click-tambjamines, Lactrans-1 facilitates transmembrane lactate transportation in liposome models and reduces cancer cell viability. The results showed that Lactrans-1 triggered both apoptosis and necrosis depending on the cell line tested, displaying a synergistic effect in combination with first-line standard chemotherapeutic cisplatin. The ability of this compound to transport outward lactate anions was confirmed in A549 and HeLa cells, two cancer cell lines having distinct rates of lactate production. In addition, through cell viability reversion experiments it was possible to establish a correlation between the amount of lactate transported and the cytotoxic effect exhibited. The movement of lactate anions was accompanied with intracellular pH disturbances that included basification of lysosomes and acidification of the cytosol and mitochondria. We also observed mitochondrial swelling, increased ROS production and activation of oxidative stress signaling pathways p38-MAPK and JNK/SAPK. Our findings provide evidence that enhancement of lactate permeability is critical for cellular pH homeostasis and effective to trigger cancer cell death, suggesting that Lactrans-1 may be a promising anticancer therapy.

Metastasis is the primary cause of death in cancer patients. Many current chemotherapeutic agents only show cytotoxic, but not antimetastatic properties. This leads to a reduction in tumor size, but allows cancer cells to disseminate, which ultimately causes patient death. Therefore, novel anticancer compounds with both effects need to be developed. In this work, we analyze the antimetastatic properties of prodigiosin and obatoclax (GX15-070), anticancer drugs of the Prodiginines (PGs) family. We studied PGs’ effects on cellular adhesion and morphology in the human primary and metastatic melanoma cell lines, SK-MEL-28 and SK-MEL-5, and in the murine melanoma cell line, B16F10A. Cell adhesion sharply decreased in the treated cells, and this was accompanied by a reduction in filopodia protrusions and a significant decrease in the number of focal-adhesion structures. Moreover, cell migration was assessed through the wound-healing assay and cell motility was severely inhibited after 24 h of treatment. To elucidate the molecular mechanisms involved, changes in metastasis-related genes were analyzed through a gene-expression array. Key genes related to cellular invasion, migration and chemoresistance were significantly down-regulated. Finally, an in vivo model of melanoma-induced lung metastasis was established and significant differences in lung tumors were observed in the obatoclax-treated mice. Altogether, these results describe, in depth, PGs’ cellular antimetastatic effects and identify in vivo antimetastatic properties of Obatoclax.

Copper‐assisted post‐Ugi reactions enable access to different heterocyclic systems, tetrahydronaphthoazetidinone, 2,5‐dioxo‐1,4‐methanobenzoazepine and 3‐hydroxypyrrolidinone derivatives. The described process affords complex scaffolds from readily available acyclic precursors using simple protocols.

Six novel click-tambjamines (1-6) bearing an alkyl chain of varying length linked to the imine moiety have been formulated in nanostructured lipid carriers (NLCs) to evaluate their transmembrane anion transport activity both when free (i.e., not encapsulated) and nanoformulated. Nanostructured lipid carriers (NLCs) are an example of drug delivery systems (DDSs) that stand out because of their versatility. In this work we show that NLCs can be used to efficiently formulate highly lipophilic anionophores and experiments conducted in model liposomes reveal that these formulations are adequate to deliver anionophores without compromising their transport activity. This result paves the way to facilitate the study of highly lipophilic anionophores and their potential use as future drugs.

Supplementary Figures: Figure S1. Set of tambjamine analogues investigated; Figure S2. General reaction scheme; Figure S3. 1H NMR (DMSO-d6) of compound 3.HCl; Figure S4. 13C (DMSO-d6) of compound 3.HCl; Figure S5. HRMS (EI) of compound 3; Figure S6. 1H NMR (DMSO-d6) of compound 4.HCl; Figure S7. 13C (DMSO-d6) of compound 4.HCl; Figure S8. 13C dept (DMSO-d6) of compound 4.HCl; Figure S9. HRMS (EI) of compound 4.; Figure S10. 1H NMR (CDCl3) of compound 5.HCl; Figure S11. 13C NMR (CDCl3) of compound 5.HCl; Figure S12. 13C dept NMR (CDCl3) of compound 5.HCl; Figure S13. HRMS (EI) of compound 5.; Figure S14. 1H NMR (CDCl3) of compound 6.HCl; Figure S15. 13C NMR (CDCl3) of compound 6.HCl; Figure S16. HRMS (EI) of compound 6.; Figure S17. 1H NMR (CDCl3) of compound 7.HCl; Figure S18. 13C NMR (CDCl3) of compound 7.HCl; Figure S19. 13C dept NMR (CDCl3) of compound 7.HCl; Figure S20. HRMS (EI) of compound 7.; Figure S21. 1H NMR (CDCl3) of compound 8.HCl; Figure S22. 13C NMR (CDCl3) of compound 8.HCl; Figure S23. 13C dept NMR (CDCl3) of compound 8.HCl; Figure S24. HRMS (EI) of compound 8.; Figure S25. 1H NMR (CDCl3) of compound 9.HCl; Figure S26. 13C NMR (CDCl3) of compound 9.HCl; Figure S27. 13C dept NMR (CDCl3) of compound 9.HCl; Figure S28. HRMS (EI) of compound 9.; Figure S29. 1H NMR (CDCl3) of compound 10.HCl; Figure S30. 13C NMR (CDCl3) of compound 10.HCl; Figure S31. 13C dept NMR (CDCl3) of compound 10.HCl; Figure S32. HRMS (EI) of compound 10; Figure S33. 1H NMR (CDCl3) of compound 11.HOAc; Figure S34. 13C NMR (CDCl3) of compound 11.HOAc; Figure S35. 13C dept NMR (CDCl3) of compound 11.HOAc; Figure S36. HRMS (EI) of compound 11; Figure S37. Dose response curves in A549, DMS53, SW900 and H460 cells; Figure S38. Dose response curves in human lung tumor-derived primay cultures; Figure S39. Array validation using TaqMan gene expression assays; Figure S40. Cell cycle assay by flow cytometry; Figure S41. Western blot of apoptotic markers in the DMS53 cell line; Figure S42. Body weight recording; Supplementary Tables: Table S1. Applied biosystem probes list used for the TaqMan gene expression assays; Table S2. List of altered genes in the cancer drug targets QIAGEN RT2 Profiler Array for the SW900 cell line; Supplementary Materials and Methods: Synthesis and characterization; Cell viability; TaqMan assays; Gene expression; Cell cycle; Western blot; Mice weight.

After more than three decades of extensive investigations on supramolecular polymers, strategies for self-limiting growth still remain challenging. Herein, we exploit a new V-shaped monomer design to achieve anticooperatively formed oligomers with superior robustness and high luminescence. In toluene, the monomer-oligomer equilibrium is shifted to the monomer side, enabling the elucidation of the molecular packing modes and the resulting (weak) anticooperativity. Steric effects associated with an antiparallel staircase organization of the dyes are proposed to outcompete aromatic and unconventional B-F⋅⋅⋅H-N/C interactions, restricting the growth at the stage of oligomers. In methylcyclohexane (MCH), the packing modes and the anticooperativity are preserved; however, pronounced solvophobic and chain-enwrapping effects lead to thermally ultrastable oligomers. Our results shed light on understanding anticooperative effects and restricted growth in self-assembly.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

QIAGEN Cancer Drug Targets Array file containing the raw data (Ct information) for the qPCR of all the conditions (both A549 and SW900 cell lines).

An excessive production of lactate by cancer cells fosters tumor growth and metastasis. Therefore, targeting lactate metabolism and transport offers a new therapeutic strategy against cancer, based on dependency of some cancer cells for lactate as energy fuel or as oncogenic signal. Herein we present a family of anionophores based on the structure of click-tambjamines that have proved to be extremely active lactate carriers across phospholipid membranes. Compound 1, the most potent lactate transmembrane carrier, was studied in HeLa cells. The use of a monocarboxylate transporters (MCTs) inhibitor proved that 1 is an active lactate transporter in living cells, confirming the results obtained in phospholipid vesicles. Moreover, an additive effect of compound 1 with cisplatin was observed in HeLa cells. Identification of active lactate anionophores working in living cells opens up ways to exploit this class of compounds as molecular tools and drugs addressing dysregulated lactate metabolism.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Photoredox catalysis constitutes a very powerful tool in organic synthesis, due to its versatility, efficiency, and the mild conditions required by photoinduced transformations. In this paper, we present an efficient and selective photocatalytic procedure for the aerobic oxidative dehydrogenation of partially saturated N-heterocycles to afford the respective N-heteroarenes (indoles, quinolines, acridines, and quinoxalines). The protocol involves the use of new Ir(III) biscyclometalated photocatalysts of the general formula [Ir(C^N)2(N^N')]Cl, where the C^N ligand is 2-(2,4-difluorophenyl)pyridinate, and N^N' are different ligands based on the 2-(2'-pyridyl)benzimidazole scaffold. In-depth electrochemical and photophysical studies as well as DFT calculations have allowed us to establish structure-activity relationships, which provide insights for the rational design of efficient metal-based dyes in photocatalytic oxidation reactions. In addition, we have formulated a dual mechanism, mediated by the radical anion superoxide, for the above-mentioned transformations.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.