RESUMEN

Telomere length plays a crucial role in cellular aging and the risk of diseases. Unlike normal cells, cancer cells can extend their own survival by maintaining telomere stability through telomere maintenance mechanism. Therefore, regulating the lengths of telomeres have emerged as a promising approach for anti-cancer treatment. In this study, we introduce a nanoscale octopus-like structure designed to induce physical entangling of telomere, thereby efficiently triggering telomere dysfunction. The nanoscale octopus, composed of eight-armed PEG (8-arm-PEG), are functionalized with cell penetrating peptide (TAT) to facilitate nuclear entry and are covalently bound to N-Methyl Mesoporphyrin IX (NMM) to target G-quadruplexes (G4s) present in telomeres. The multi-armed configuration of the nanoscale octopus enables targeted binding to multiple G4s, physically disrupting and entangling numerous telomeres, thereby triggering telomere dysfunction. Both in vitro and in vivo experiments indicate that the nanoscale octopus significantly inhibits cancer cell proliferation, induces apoptosis through telomere entanglement, and ultimately suppresses tumor growth. This research offers a novel perspective for the development of innovative anti-cancer interventions and provides potential therapeutic options for targeting telomeres.

Asunto(s)

Apoptosis , Telómero , Telómero/metabolismo , Apoptosis/efectos de los fármacos , Humanos , Animales , Línea Celular Tumoral , Ratones , G-Cuádruplex/efectos de los fármacos , Ratones Desnudos , Polietilenglicoles/química , Proliferación Celular/efectos de los fármacos , Ratones Endogámicos BALB C , Neoplasias/patología , Neoplasias/tratamiento farmacológico , Femenino , Péptidos de Penetración Celular/química , Péptidos de Penetración Celular/farmacología , Nanoestructuras/química

RESUMEN

DNA chains with sequential guanine (G) repeats can lead to the formation of G-quadruplexes (G4), which are found in functional DNA and RNA regions like telomeres and oncogene promoters. The development of molecules with adequate structural features to selectively stabilize G4 structures can counteract cell immortality, highly described for cancer cells, and also downregulate transcription events underlying cell apoptosis and/or senescence processes. We describe here, the efficiency of four highly charged porphyrins-phosphonium conjugates to act as G4 stabilizing agents. The spectrophotometric results allowed to select the conjugates P2-PPh3 and P3-PPh3 as the most promising ones to stabilize selectively G4 structures. Molecular dynamics simulation experiments were performed and support the preferential binding of P2-PPh3 namely to MYC and of P3-PPh3 to KRAS. The ability of both ligands to block the activity of Taq polymerase was confirmed and also their higher cytotoxicity against the two melanoma cell lines A375 and SK-MEL-28 than to immortalized skin keratinocytes. Both ligands present efficient cellular uptake, nuclear co-localization and high ability to generate 1O2 namely when interacting with G4 structure. The obtained data points the synthesized porphyrins as promising ligands to be used in a dual approach that can combine G4 stabilization and Photodynamic therapy (PDT).

Asunto(s)

G-Cuádruplex , Porfirinas , Telómero , G-Cuádruplex/efectos de los fármacos , Porfirinas/química , Porfirinas/farmacología , Humanos , Telómero/química , Línea Celular Tumoral , Compuestos Organofosforados/química , Compuestos Organofosforados/farmacología , Simulación de Dinámica Molecular , Ligandos , Oncogenes

RESUMEN

Limiting cellular plasticity is of key importance for the therapeutic targeting of metastatic breast cancer (MBC). Fibroblast growth receptor (FGFR) is a critical molecule in cellular plasticity and potent inhibitors of FGFR enzymatic activity have been developed, but kinase independent functions for this receptor also contribute to MBC progression. Herein, we evaluated several FGFR inhibitors and find that while FGFR-targeted kinase inhibitors are effective at blocking ligand-induced cell growth, dormant cells persist eventually giving rise to MBC progression. To more broadly target FGFR and cellular plasticity, we examined the FGFR1 proximal promoter, and found several sequences with potential to form G-quadruplex secondary structures. Circular dichroism was used to verify formation of G-quadruplex in the FGFR1 proximal promoter. Importantly, use of the clinical G-quadruplex-stabilizing compound, CX-5461, stabilized the FGFR1 G-quadruplex structures, blocked the transcriptional activity of the FGFR1 proximal promoter, decreased FGFR1 expression, and resulted in potent inhibition of pulmonary tumor formation. Overall, our findings suggest G-quadruplex-targeted compounds could be a potential therapeutic strategy to limit the cellular plasticity of FGFR1 overexpressing MBC.

Asunto(s)

Neoplasias de la Mama , G-Cuádruplex , Regiones Promotoras Genéticas , Receptor Tipo 1 de Factor de Crecimiento de Fibroblastos , G-Cuádruplex/efectos de los fármacos , Humanos , Neoplasias de la Mama/patología , Neoplasias de la Mama/genética , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/metabolismo , Femenino , Receptor Tipo 1 de Factor de Crecimiento de Fibroblastos/metabolismo , Receptor Tipo 1 de Factor de Crecimiento de Fibroblastos/genética , Animales , Línea Celular Tumoral , Ratones , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Metástasis de la Neoplasia

RESUMEN

G-quadruplex (G4) sequences, which can fold into higher-order G4 structures, are abundant in the human genome and are over-represented in the promoter regions of many genes involved in human cancer initiation, progression, and metastasis. They are plausible targets for G4-binding small molecules, which would, in the case of promoter G4s, result in the transcriptional downregulation of these genes. However, structural information is currently available on only a very small number of G4s and their ligand complexes. This limitation, coupled with the currently restricted information on the G4-containing genes involved in most complex human cancers, has led to the development of a phenotypic-led approach to G4 ligand drug discovery. This approach was illustrated by the discovery of several generations of tri- and tetra-substituted naphthalene diimide (ND) ligands that were found to show potent growth inhibition in pancreatic cancer cell lines and are active in in vivo models for this hard-to-treat disease. The cycles of discovery have culminated in a highly potent tetra-substituted ND derivative, QN-302, which is currently being evaluated in a Phase 1 clinical trial. The major genes whose expression has been down-regulated by QN-302 are presented here: all contain G4 propensity and have been found to be up-regulated in human pancreatic cancer. Some of these genes are also upregulated in other human cancers, supporting the hypothesis that QN-302 is a pan-G4 drug of potential utility beyond pancreatic cancer.

Asunto(s)

Antineoplásicos , Descubrimiento de Drogas , G-Cuádruplex , G-Cuádruplex/efectos de los fármacos , Humanos , Descubrimiento de Drogas/métodos , Ligandos , Antineoplásicos/farmacología , Antineoplásicos/química , Fenotipo , Línea Celular Tumoral , Naftalenos/farmacología , Naftalenos/química , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Animales , Imidas/química , Imidas/farmacología , Regiones Promotoras Genéticas

RESUMEN

c-MYC is one of the most important oncogenes, which is overexpressed in many cancers, and is highly related to development, metastasis, and drug resistance of cancers. The G4 structure in the promoter of c-MYC oncogene contributes a lot to the gene transcriptional mechanism. Small-molecule ligands binding to the c-MYC G4 appear to be a new class of anticancer agents. However, selective ligands for the c-MYC G4 over other G4s have been rarely reported. In this study, we reported a novel fluorescent ligand by migrating the benzene group on a carbazole-benzothiazolium scaffold, which was demonstrated to exhibit considerable specificity to the c-MYC G4, which was distinguished from other small-molecule ligands. The further cellular experiments suggested that this ligand may indeed target the promoter G4 and cause apparent transcriptional inhibition of the c-MYC oncogene instead of other G4-mediated oncogenes, which thereby resulted in cancer cell growth inhibition. Collectively, this study provided a good example for developing specific c-MYC G4 ligands, which may further develop into an effective anticancer agent that inhibit the c-MYC expression.

Asunto(s)

Antineoplásicos , Benzotiazoles , Carbazoles , Proliferación Celular , Colorantes Fluorescentes , G-Cuádruplex , Proteínas Proto-Oncogénicas c-myc , Carbazoles/química , Carbazoles/farmacología , G-Cuádruplex/efectos de los fármacos , Humanos , Ligandos , Benzotiazoles/química , Benzotiazoles/farmacología , Proteínas Proto-Oncogénicas c-myc/metabolismo , Proteínas Proto-Oncogénicas c-myc/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-myc/genética , Colorantes Fluorescentes/química , Colorantes Fluorescentes/síntesis química , Colorantes Fluorescentes/farmacología , Estructura Molecular , Antineoplásicos/farmacología , Antineoplásicos/química , Antineoplásicos/síntesis química , Proliferación Celular/efectos de los fármacos , Relación Estructura-Actividad , Ensayos de Selección de Medicamentos Antitumorales , Relación Dosis-Respuesta a Droga , Benceno/química , Benceno/farmacología , Línea Celular Tumoral

RESUMEN

Nitrobenzoxadiazole (NBD)-incorporated naphthalene diimide derivatives were designed and synthesized as candidates of antitumor agents with cytotoxicity against human pancreatic cancer cell MIA PaCa-2. Among these, compounds 1NND and 3NND exhibited fluorescent "turn-off" property toward human telomeric G-quadruplex (G4), which allows the direct measurement of dissociation constant (Kd) of ligands against G4 by fluorescence titration method. Notably, the compound 1NND not only exhibited great cytotoxic activity against MIA PaCa-2 with a half maximal inhibitory concentration (IC50) of 77.9 nM, but also exhibited high affinity against G4 with Kd of 1.72 µM. Furthermore, the target binding properties were investigated by circular dichroism (CD) spectra and further studied by molecular docking methods.

Asunto(s)

Antineoplásicos , Diseño de Fármacos , G-Cuádruplex , Imidas , Naftalenos , Humanos , Antineoplásicos/farmacología , Antineoplásicos/síntesis química , Antineoplásicos/química , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Colorantes Fluorescentes/química , Colorantes Fluorescentes/síntesis química , Colorantes Fluorescentes/farmacología , G-Cuádruplex/efectos de los fármacos , Imidas/química , Imidas/farmacología , Imidas/síntesis química , Ligandos , Simulación del Acoplamiento Molecular , Estructura Molecular , Naftalenos/química , Naftalenos/farmacología , Naftalenos/síntesis química , Relación Estructura-Actividad

RESUMEN

Chagas disease is caused by the parasite Trypanosoma cruzi and affects over 7 million people worldwide. The two actual treatments, Benznidazole (Bzn) and Nifurtimox, cause serious side effects due to their high toxicity leading to treatment abandonment by the patients. In this work, we propose DNA G-quadruplexes (G4) as potential therapeutic targets for this infectious disease. We have found 174 PQS per 100,000 nucleotides in the genome of T. cruzi and confirmed G4 formation of three frequent motifs. We synthesized a family of 14 quadruplex ligands based in the dithienylethene (DTE) scaffold and demonstrated their binding to these identified G4 sequences. Several DTE derivatives exhibited micromolar activity against epimastigotes of four different strains of T. cruzi, in the same concentration range as Bzn. Compounds L3 and L4 presented remarkable activity against trypomastigotes, the active form in blood, of T. cruzi SOL strain (IC50 = 1.5-3.3 µM, SI = 25-40.9), being around 40 times more active than Bzn and displaying much better selectivity indexes.

Asunto(s)

Enfermedad de Chagas , G-Cuádruplex , Tripanocidas , Trypanosoma cruzi , Trypanosoma cruzi/efectos de los fármacos , G-Cuádruplex/efectos de los fármacos , Ligandos , Enfermedad de Chagas/tratamiento farmacológico , Tripanocidas/farmacología , Tripanocidas/química , Tripanocidas/síntesis química , Humanos , Estructura Molecular , Relación Estructura-Actividad , Relación Dosis-Respuesta a Droga , Pruebas de Sensibilidad Parasitaria , Antiparasitarios/farmacología , Antiparasitarios/química , Antiparasitarios/síntesis química

RESUMEN

Human telomerase reverse transcriptase (hTERT) may have noncanonical functions in transcriptional regulation and metabolic reprogramming in cancer cells, but it is a challenging target. We thus developed small-molecule ligands targeting hTERT promoter G-quadruplex DNA structures (hTERT G4) to downregulate hTERT expression. Ligand 5 showed high affinity toward hTERT G4 (Kd = 1.1 µM) and potent activity against triple-negative breast cancer cells (MDA-MB-231, IC50 = 1 µM). In cell-based assays, 5 not only exerts markedly inhibitory activity on classical telomere functions including decreased telomerase activity, shortened telomere length, and cellular senescence but also induces DNA damage, acute cellular senescence, and apoptosis. This study reveals that hTERT G4-targeting ligand may cause mitochondrial dysfunction, disrupt iron metabolism and activate ferroptosis in cancer cells. The in vivo antitumor efficacy of 5 was also evaluated in an MDA-MB-231 xenograft mouse model and approximately 78.7% tumor weight reduction was achieved. No observable toxicity against the major organs was observed.

Asunto(s)

Antineoplásicos , Regulación hacia Abajo , G-Cuádruplex , Regiones Promotoras Genéticas , Telomerasa , Neoplasias de la Mama Triple Negativas , Telomerasa/antagonistas & inhibidores , Telomerasa/metabolismo , Humanos , G-Cuádruplex/efectos de los fármacos , Neoplasias de la Mama Triple Negativas/tratamiento farmacológico , Neoplasias de la Mama Triple Negativas/patología , Animales , Ligandos , Femenino , Regulación hacia Abajo/efectos de los fármacos , Ratones , Antineoplásicos/farmacología , Antineoplásicos/química , Antineoplásicos/uso terapéutico , Línea Celular Tumoral , Bibliotecas de Moléculas Pequeñas/química , Bibliotecas de Moléculas Pequeñas/farmacología , Apoptosis/efectos de los fármacos , Ensayos Antitumor por Modelo de Xenoinjerto , Ratones Desnudos , Senescencia Celular/efectos de los fármacos , Ratones Endogámicos BALB C

RESUMEN

G-quadruplex (G4) structures play integral roles in modulating biological functions and can be regulated by small molecules. The MYC gene is critical during tumor initiation and malignant progression, in which G4 acts as an important modulation motif. Herein, we reported the MYC promoter G4 recognized by a platinum(II) compound Pt-phen. Two Pt-phen-MYC G4 complex structures in 5 mM K+ were determined by NMR. The Pt-phen first strongly binds the 3'-end of MYC G4 to form a 1:1 3'-end binding complex and then binds 5'-end to form a 2:1 complex with more Pt-phen. In the complexes, the Pt-phen molecules are well-defined and stack over four bases at the G-tetrad for a highly extensive π-π interaction, with the Pt atom aligning with the center of the G-tetrad. The flanking residues were observed to rearrange and cover on top of Pt-phen to stabilize the whole complex. We further demonstrated that Pt-phen targets G4 DNA in living cells and represses MYC gene expression in cancer cells. Our work elucidated the structural basis of ligand binding to MYC promoter G4. The platinum compound bound G4 includes multiple complexes formation, providing insights into the design of metal ligands targeting oncogene G4 DNA.

Asunto(s)

G-Cuádruplex , Regiones Promotoras Genéticas , Proteínas Proto-Oncogénicas c-myc , G-Cuádruplex/efectos de los fármacos , Humanos , Proteínas Proto-Oncogénicas c-myc/metabolismo , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/química , ADN/química , ADN/metabolismo , Compuestos de Platino/química , Genes myc , Platino (Metal)/química

RESUMEN

DNA G-quadruplex(G4) is a guanine-rich single-stranded DNA sequence that spontaneously folds into a spherical four-stranded DNA secondary structure in oncogene promoter sequences and telomeres. G4s are highly associated with the occurrence and development of cancer and have emerged as promising anticancer targets. Natural products have long been important sources of anticancer drug development. In recent years, significant progress has been made in the discovery of natural drugs targeting DNA G4s, with many DNA G4s have been confirmed as promising targets of natural products, including MYC-G4, KRAS-G4, PDGFR-ß-G4, BCL-2-G4, VEGF-G4, and telomeric G4. This review summarizes the research progress in discovering natural small molecules that target DNA G4s and their binding mechanisms. It also discusses the opportunities of and challenges in developing drugs targeting DNA G4s. This review will serve as a valuable reference for the research on natural products, particularly in the development of novel antitumor medications.

Asunto(s)

Productos Biológicos , G-Cuádruplex , G-Cuádruplex/efectos de los fármacos , Productos Biológicos/química , Productos Biológicos/farmacología , Humanos , Animales , ADN/química , ADN/genética , Neoplasias/tratamiento farmacológico , Neoplasias/genética , Antineoplásicos/química , Antineoplásicos/farmacología

RESUMEN

G-Quadruplex DNA (GQ-DNA) is one of the most important non-canonical nucleic acid structures. GQ-DNA forming sequences are present in different crucial genomic regions and are abundant in promoter regions of several oncogenes. Therefore, GQ-DNA is an important target for anticancer drugs and hence binding interactions between GQ-DNA and small molecule ligands are of great importance. Since GQ-DNA is a highly polymorphic structure, it is important to identify ligand molecules which preferentially target a particular quadruplex sequence. In this present study, we have used a FDA approved drug called imatinib mesylate (ligand) which is a selective tyrosine kinase inhibitor, successfully used for the treatment of chronic myelogenous leukaemia, gastrointestinal stromal tumours. Different spectroscopic techniques as well as molecular docking investigations and molecular simulations have been used to explore the interaction between imatinib mesylate with VEGF GQ DNA structures along with duplex DNA, C-Myc, H-Telo GQ DNA. We found that imatinib mesylate shows preferential interaction towards VEGF GQ DNA compared to C-Myc, H-Telo GQ and duplex DNA. Imatinib mesylate seems to be an efficient ligand for VEGF GQ DNA, suggesting that it might be used to regulate the expression of genes in cancerous cells.

Asunto(s)

Antineoplásicos , G-Cuádruplex , Mesilato de Imatinib , Simulación del Acoplamiento Molecular , Factor A de Crecimiento Endotelial Vascular , Mesilato de Imatinib/uso terapéutico , Mesilato de Imatinib/química , Mesilato de Imatinib/farmacología , G-Cuádruplex/efectos de los fármacos , Humanos , Factor A de Crecimiento Endotelial Vascular/metabolismo , Factor A de Crecimiento Endotelial Vascular/química , Antineoplásicos/química , Antineoplásicos/uso terapéutico , Neoplasias/tratamiento farmacológico , Neoplasias/metabolismo , Neoplasias/genética , ADN/química , ADN/metabolismo

RESUMEN

Targeted protein degradation through PROteolysis TArgeting Chimeras (PROTACs) is a relatively new modality in cellular interventions. The minimum requirement for PROTACs to function is forming a tertiary complex of the protein of interest (POI), E3 ligase, and the molecular glue PROTAC. Here, we propose a new approach to modulate the nano-environment interactome of a non-protein target through a plausible quaternary complex of interactome-biomolecule of interest (BOI)-PROTAC and E3 ligase. We report nucleic acid-targeting PROTAC (NA-TAC) molecules by conjugating DNA-binding and E3 ligase ligands. We demonstrate that NA-TACs can target the G-quadruplex DNA and induce elevated DNA damage and cytotoxicity compared to the conventional G-quadruplex binding ligands. Our new class of NA-TACs lays the foundation for small molecule-based non-protein targeting PROTACs for interactome and nanoenvironment mapping and nucleic acid-targeted precision medicines.

Asunto(s)

Antineoplásicos , G-Cuádruplex , Proteolisis , Ubiquitina-Proteína Ligasas , Humanos , Antineoplásicos/farmacología , Antineoplásicos/química , Antineoplásicos/síntesis química , Proteolisis/efectos de los fármacos , Ubiquitina-Proteína Ligasas/metabolismo , G-Cuádruplex/efectos de los fármacos , Línea Celular Tumoral , Daño del ADN/efectos de los fármacos , Ligandos , Ácidos Nucleicos/química , Ácidos Nucleicos/metabolismo , ADN/química , ADN/metabolismo , Quimera Dirigida a la Proteólisis

RESUMEN

A novel class of compounds designed to hit two anti-tumour targets, G-quadruplex structures and human carbonic anhydrases (hCAs) IX and XII is proposed. The induction/stabilisation of G-quadruplex structures by small molecules has emerged as an anticancer strategy, disrupting telomere maintenance and reducing oncogene expression. hCAs IX and XII are well-established anti-tumour targets, upregulated in many hypoxic tumours and contributing to metastasis. The ligands reported feature a berberine G-quadruplex stabiliser scaffold connected to a moiety inhibiting hCAs IX and XII. In vitro experiments showed that our compounds selectively stabilise G-quadruplex structures and inhibit hCAs IX and XII. The crystal structure of a telomeric G-quadruplex in complex with one of these ligands was obtained, shedding light on the ligand/target interaction mode. The most promising ligands showed significant cytotoxicity against CA IX-positive HeLa cancer cells in hypoxia, and the ability to stabilise G-quadruplexes within tumour cells.

Asunto(s)

Antineoplásicos , Anhidrasa Carbónica IX , Inhibidores de Anhidrasa Carbónica , Anhidrasas Carbónicas , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , G-Cuádruplex , Humanos , G-Cuádruplex/efectos de los fármacos , Inhibidores de Anhidrasa Carbónica/farmacología , Inhibidores de Anhidrasa Carbónica/química , Inhibidores de Anhidrasa Carbónica/síntesis química , Antineoplásicos/farmacología , Antineoplásicos/química , Antineoplásicos/síntesis química , Relación Estructura-Actividad , Estructura Molecular , Anhidrasa Carbónica IX/antagonistas & inhibidores , Anhidrasa Carbónica IX/metabolismo , Anhidrasas Carbónicas/metabolismo , Proliferación Celular/efectos de los fármacos , Ligandos , Células HeLa , Antígenos de Neoplasias/metabolismo , Modelos Moleculares

RESUMEN

Noncanonical nucleic acid structures, particularly G-quadruplexes, have garnered significant attention as potential therapeutic targets in cancer treatment. Here, the recognition of G-quadruplex DNA by peptides derived from the Rap1 protein is explored, with the aim of developing novel peptide-based G-quadruplex ligands with enhanced selectivity and anticancer activity. Biophysical techniques were employed to assess the interaction of a peptide derived from the G-quadruplex-binding domain of the protein with various biologically relevant G-quadruplex structures. Through alanine scanning mutagenesis, key amino acids crucial for G-quadruplex recognition were identified, leading to the discovery of two peptides with improved G-quadruplex-binding properties. However, despite their in vitro efficacy, these peptides showed limited cell penetration and anticancer activity. To overcome this challenge, cell-penetrating peptide (CPP)-conjugated derivatives were designed, some of which exhibited significant cytotoxic effects on cancer cells. Interestingly, selected CPP-conjugated peptides exerted potent anticancer activity across various tumour types via a G-quadruplex-dependent mechanism. These findings underscore the potential of peptide-based G-quadruplex ligands in cancer therapy and pave the way for the development of novel therapeutic strategies targeting these DNA structures.

Asunto(s)

Antineoplásicos , Péptidos de Penetración Celular , G-Cuádruplex , G-Cuádruplex/efectos de los fármacos , Humanos , Antineoplásicos/farmacología , Antineoplásicos/química , Péptidos de Penetración Celular/química , Péptidos de Penetración Celular/farmacología , Línea Celular Tumoral , Péptidos/química , Péptidos/farmacología , Ligandos , ADN/química , ADN/metabolismo , Complejo Shelterina/metabolismo , Complejo Shelterina/química , Unión Proteica

RESUMEN

Telomere replication is essential for continued proliferation of human cells, such as stem cells and cancer cells. Telomerase lengthens the telomeric G-strand, while C-strand replication is accomplished by CST-polymerase α-primase (CST-PP). Replication of both strands is inhibited by formation of G-quadruplex (GQ) structures in the G-rich single-stranded DNA. TMPyP4 and pyridostatin (PDS), which stabilize GQ structures in both DNA and RNA, inhibit telomerase in vitro, and in human cells they cause telomere shortening that has been attributed to telomerase inhibition. Here, we show that TMPyP4 and PDS also inhibit C-strand synthesis by stabilizing DNA secondary structures and thereby preventing CST-PP from binding to telomeric DNA. We also show that these small molecules inhibit CST-PP binding to a DNA sequence containing no consecutive guanine residues, which is unlikely to form GQs. Thus, while these "telomerase inhibitors" indeed inhibit telomerase, they are also robust inhibitors of telomeric C-strand synthesis. Furthermore, given their binding to GQ RNA and their limited specificity for GQ structures, they may disrupt many other protein-nucleic acid interactions in human cells.

Asunto(s)

Inhibidores Enzimáticos , G-Cuádruplex , Telomerasa , Telómero , Telomerasa/antagonistas & inhibidores , Telomerasa/metabolismo , Telomerasa/genética , Humanos , Telómero/metabolismo , G-Cuádruplex/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/síntesis química , Ácidos Picolínicos/farmacología , Ácidos Picolínicos/química , Replicación del ADN/efectos de los fármacos , ADN Polimerasa I/antagonistas & inhibidores , ADN Polimerasa I/metabolismo , ADN/metabolismo , Aminoquinolinas , Porfirinas , ADN Primasa

RESUMEN

Water-soluble phthalocyanine (Pc) derivatives have been regarded as potential G-quadruplex (G4) nucleic acid-targeting ligands for anticancer therapy and have been extensively studied as effective photosensitizers for photodynamic therapy (PDT). Understanding how photosensitizers interact with nucleic acids and the subsequent photolytic reactions is essential for deciphering the initial steps of PDT, thereby aiding in the development of new photosensitizing agents. In this study, we found that red-light irradiation of a mixture of a Zn(II) Pc derivative and an all-parallel G4 DNA leads to catalytic and selective photodegradation of the DNA by reactive oxygen species (ROS) generated from the Zn(II) Pc derivative bound to DNA through a reaction mechanism similar to that of an enzyme reaction. This finding provides a novel insight into the molecular design of a photosensitizer to enhance its PDT efficacy.

Asunto(s)

ADN , G-Cuádruplex , Indoles , Isoindoles , Luz , Fotólisis , Fármacos Fotosensibilizantes , G-Cuádruplex/efectos de los fármacos , Indoles/química , Indoles/farmacología , Fármacos Fotosensibilizantes/química , Fármacos Fotosensibilizantes/farmacología , Fármacos Fotosensibilizantes/efectos de la radiación , ADN/química , Fotólisis/efectos de la radiación , Catálisis , Compuestos Organometálicos/química , Compuestos Organometálicos/farmacología , Zinc/química , Zinc/farmacología , Compuestos de Zinc/química , Especies Reactivas de Oxígeno/metabolismo , Fotoquimioterapia , Luz Roja

RESUMEN

The role of G-quadruplex (G4) in cellular processes can be investigated by the covalent modification of G4-DNA using alkylating reagents. Controllable alkylating reagents activated by external stimuli can react elegantly and selectively. Herein, we report a chemical activation system that can significantly boost the reaction rate of methylamine-protected vinyl-quinazolinone (VQ) derivative for the alkylation of G4-DNA. The two screened activators can transform low-reactive VQ-NHR' to highly reactive intermediates following the Michael addition mechanism. This approach expands the toolbox of activable G4 alkylating reagents.

Asunto(s)

G-Cuádruplex , Metilaminas , Quinazolinonas , Alquilación , G-Cuádruplex/efectos de los fármacos , Metilaminas/química , Metilaminas/farmacología , Metilaminas/síntesis química , Quinazolinonas/química , Quinazolinonas/farmacología , Quinazolinonas/síntesis química , Humanos , Estructura Molecular , ADN/química , Compuestos de Vinilo/química , Compuestos de Vinilo/farmacología

RESUMEN

Several G-quadruplex nucleic acid (G4s) ligands have been developed seeking target selectivity in the past decade. Naphthalene diimide (NDI)-based compounds are particularly promising due to their biological activity and red-fluorescence emission. Previously, we demonstrated the existence of G4s in the promoter region of parasite genomes, assessing the effectiveness of NDI-derivatives against them. Here, we explored the biological activity of a small library of G4-DNA ligands, exploiting the NDI pharmacophore, against both Trypanosoma brucei and Leishmania major parasites. Biophysical and biological assays were conducted. Among the various families analyzed, core-extended NDIs exhibited the most promising results concerning the selectivity and antiparasitic effects. NDI 16 emerged as the most potent, with an IC50 of 0.011 nM against T. brucei and remarkable selectivity vs MRC-5 cells (3454-fold). Fascinating, 16 is 480-fold more potent than the standard drug pentamidine (IC50 = 5.3 nM). Cellular uptake and parasite localization were verified by exploiting core-extended NDI red-fluorescent emission.

Asunto(s)

G-Cuádruplex , Imidas , Leishmania major , Naftalenos , Tripanocidas , Trypanosoma brucei brucei , G-Cuádruplex/efectos de los fármacos , Relación Estructura-Actividad , Naftalenos/farmacología , Naftalenos/química , Imidas/química , Imidas/farmacología , Ligandos , Trypanosoma brucei brucei/efectos de los fármacos , Tripanocidas/farmacología , Tripanocidas/química , Tripanocidas/síntesis química , Humanos , Leishmania major/efectos de los fármacos , Línea Celular

RESUMEN

The industrial world exposes living organisms to a variety of metal pollutants. Here we investigated whether such elements affect G-rich sequences susceptible to fold into G-quadruplex (GQ) structures. Thermal stability and conformation of these oligoncleotides was studied at various molar ratios of a variety of heavy metal salts using thermal FRET, transition-FRET (t-FRET) and circular dichroism. Metal ions affected the thermal stability of the GQs to different extents; some metals had no effect on Tm while other metals caused small to moderate changes in Tm at 1:1 or 1:10 molar ratio. While most of the metals had no major effect, Al3+, Cd2+, Pb2+, Hg2+ and Zn2+ altered the thermal stability and structural features of the GQs. Some metals such as Pb2+ and Hg2+ exhibit differential interactions with telomere, c-myc and c-kit GQs. Overall, toxic heavy metals affect G-quadruplex stability in a sequence and topology dependent manner. This study provides new insight into how heavy metal exposure may affect gene expression and cellular responses.

Asunto(s)

G-Cuádruplex , Metales Pesados , G-Cuádruplex/efectos de los fármacos , Metales Pesados/química , ADN/química , Dicroismo Circular , Telómero/química , Transferencia Resonante de Energía de Fluorescencia , Humanos , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/química , Proteínas Proto-Oncogénicas c-kit/genética , Proteínas Proto-Oncogénicas c-kit/química , Proteínas Proto-Oncogénicas c-kit/metabolismo

RESUMEN

BACKGROUND: G-quadruplex DNA (G4) is a non-canonical structure forming in guanine-rich regions, which play a vital role in cancer biology and are now being acknowledged in both nuclear and mitochondrial (mt) genome. However, the impact of G4-based targeted therapy on both nuclear and mt genome, affecting mt function and its underlying mechanisms remain largely unexplored. METHODS: The mechanisms of action and therapeutic effects of a G4-binding platinum(II) complex, Pt-ttpy, on mitochondria were conducted through a comprehensive approaches with in vitro and in vivo models, including ICP-MS for platinum measurement, PCR-based genetic analysis, western blotting (WB), confocal microscope for mt morphology study, extracellular flux analyzer, JC1 and Annexin V apoptosis assay, flow cytometry and high content microscope screening with single-cell quantification of both ROS and mt specific ROS, as well as click-chemistry for IF study of mt translation. Decipher Pt-ttpy effects on nuclear-encoded mt related genes expression were undertaken via RNA-seq, Chip-seq and CUT-RUN assays. RESULTS: Pt-ttpy, shows a highest accumulation in the mitochondria of A2780 cancer cells as compared with two other platinum(II) complexes with no/weak G4-binding properties, Pt-tpy and cisplatin. Pt-ttpy induces mtDNA deletion, copy reduction and transcription inhibition, hindering mt protein translation. Functional analysis reveals potent mt dysfunction without reactive oxygen species (ROS) induction. Mechanistic study provided first evidence that most of mt ribosome genes are highly enriched in G4 structures in their promoter regions, notably, Pt-ttpy impairs most nuclear-encoded mt ribosome genes' transcription through dampening the recruiting of transcription initiation and elongation factors of NELFB and TAF1 to their promoter with G4-enriched sequences. In vivo studies show Pt-ttpy's efficient anti-tumor effects, disrupting mt genome function with fewer side effects than cisplatin. CONCLUSION: This study underscores Pt-ttpy as a G4-binding platinum(II) complex, effectively targeting cancer mitochondria through dual action on mt and nuclear G4-enriched genomes without inducing ROS, offering promise for safer and effective platinum-based G4-targeted cancer therapy.

Asunto(s)

G-Cuádruplex , Mitocondrias , G-Cuádruplex/efectos de los fármacos , Humanos , Mitocondrias/metabolismo , Mitocondrias/efectos de los fármacos , Línea Celular Tumoral , Genoma Mitocondrial , Antineoplásicos/farmacología , Neoplasias/tratamiento farmacológico , Neoplasias/genética , Neoplasias/metabolismo , Platino (Metal)/farmacología , Animales