RESUMEN
Huntington's disease is a neurodegenerative, trinucleotide repeat (TNR) disorder affecting both males and females. It is caused by an abnormal increase in the length of CAGâ¢CTG TNR in exon 1 of the Huntingtin gene (HTT). The resultant, mutant HTT mRNA and protein cause neuronal toxicity, suggesting that reduction of their levels would constitute a promising therapeutic approach. We previously reported a novel strategy in which chemically modified oligonucleotides (ONs) directly target chromosomal DNA. These anti-gene ONs were able to downregulate both HTT mRNA and protein. In this study, various locked nucleic acid (LNA)/DNA mixmer anti-gene ONs were tested to investigate the effects of varying ON length, LNA content, and fatty acid modification on HTT expression. Altering the length did not significantly influence the ON potency, while LNA content was critical for activity. Utilization of palmitoyl-modified LNA monomers enhanced the ON activity relatively to the corresponding nonmodified LNA under serum starvation conditions. Furthermore, the number of palmitoylated LNA monomers and their positioning greatly affected ON potency. In addition, we performed RNA sequencing analysis, which showed that the anti-gene ONs affect the "immune system process, mRNA processing, and neurogenesis." Furthermore, we observed that for repeat containing genes, there is a higher tendency for antisense off-targeting. Taken together, our findings provide an optimized design of anti-gene ONs that could potentially be developed as DNA-targeting therapeutics for this class of TNR-related diseases.
Asunto(s)
Enfermedad de Huntington , Oligonucleótidos , Masculino , Humanos , Oligonucleótidos/genética , Oligonucleótidos/farmacología , Oligonucleótidos/química , Oligonucleótidos Antisentido/farmacología , ADN/uso terapéutico , Expresión Génica , ARN Mensajero/metabolismo , Proteína Huntingtina/genética , Enfermedad de Huntington/genética , Enfermedad de Huntington/terapiaRESUMEN
2'-O-(N-(Aminoethyl)carbamoyl)methyl (2'-O-AECM)-modified oligonucleotides (ONs) and their mixmers with 2'-O-methyl oligonucleotides (2'-OMe ONs) with phosphodiester linkers as well as with partial and full phosphorothioate (PS) inclusion were synthesized and functionally evaluated as splice-switching oligonucleotides in several different reporter cell lines originating from different tissues. This was enabled by first preparing the AECM-modified A, C, G and U, which required a different strategy for each building block. The AECM modification has previously been shown to provide high resistance to enzymatic degradation, even without PS linkages. It is therefore particularly interesting and unprecedented that the 2'-O-AECM ONs are shown to have efficient splice-switching activity even without inclusion of PS linkages and found to be as effective as 2'-OMe PS ONs. Importantly, the PS linkages can be partially included, without any significant reduction in splice-switching efficacy. This suggests that AECM modification has the potential to be used in balancing the PS content of ONs. Furthermore, conjugation of 2'-O-AECM ONs to an endosomal escape peptide significantly increased splice-switching suggesting that this effect could possibly be due to an increase in uptake of ON to the site of action.
Asunto(s)
Oligonucleótidos Antisentido , Oligonucleótidos Fosforotioatos , Línea Celular , Oligonucleótidos Antisentido/química , Oligonucleótidos Antisentido/genética , Oligonucleótidos Fosforotioatos/química , Oligonucleótidos Fosforotioatos/genéticaRESUMEN
AIM: The aim was to study how first-line managers act to make structural empowerment accessible for nursing staff and furthermore to relate these observations to the manager's and their nursing staff's descriptions regarding the staff's access to empowering structures. BACKGROUND: Staff access to empowering structures has been linked to positive workplace outcomes. Managers play an important role in providing the conditions for structural empowerment. METHOD: Five first-line managers were observed for two workdays. Managers and staff (n = 13) were thereafter interviewed. Field notes and interviews were analysed using directed content analysis. RESULTS: The managers displayed intentional actions that could enable their staff access to empowering structures. Managers and staff described the importance of staff's access to empowering structures. CONCLUSION: Staff who perceive to have access to structural empowerment have managers who are present and available. Unanimity among managers and staff existed in regard to the importance of staff having access to structural empowerment. The managers work continually and intentionally, doing many things at the same time, to provide the staff access to empowering structures. IMPLICATIONS FOR NURSING MANAGEMENT: The study shows the importance of promoting managers' awareness of staff's access to structural empowerment and maximizing managers' presence and availability to their staff.
Asunto(s)
Empoderamiento , Poder Psicológico , Humanos , Encuestas y Cuestionarios , Lugar de TrabajoRESUMEN
BACKGROUND: There is a need for high-quality research regarding exercise interventions for persons with anxiety disorders. We investigate whether a 12-week exercise intervention, with different intensities, could reduce anxiety symptoms in patients with anxiety disorders. METHODS: 286 patients were recruited from primary care in Sweden. Severity of symptoms was self-assessed using the Beck Anxiety Inventory (BAI) and the Montgomery Åsberg Depression Rating Scale (MADRS-S). Participants were randomly assigned to one of two group exercise programs with cardiorespiratory and resistance training and one control/standard treatment non-exercise group, with 1:1:1 allocation. RESULTS: Patients in both exercise groups showed larger improvements in both anxiety and depressive symptoms compared to the control group. No differences in effect sizes were found between the two groups. To study a clinically relevant improvement, BAI and MADRS-S were dichotomized with the mean change in the control group as reference. In adjusted models the odds ratio for improved symptoms of anxiety after low-intensity training was 3.62 (CI 1.34-9.76) and after moderate/high intensity 4.88 (CI 1.66-14.39), for depressive symptoms 4.96 (CI 1.81-13.6) and 4.36 (CI 1.57-12.08) respectively. There was a significant intensity trend for improvement in anxiety symptoms. LIMITATIONS: The use of self-rating measures which bears the risk of an under- or overestimation of symptoms. CONCLUSIONS: A 12-week group exercise program proved effective for patients with anxiety syndromes in primary care. These findings strengthen the view of physical exercise as an effective treatment and could be more frequently made available in clinical practice for persons with anxiety issues.
Asunto(s)
Trastornos de Ansiedad , Ansiedad , Ansiedad/terapia , Trastornos de Ansiedad/terapia , Depresión/terapia , Ejercicio Físico , Humanos , Atención Primaria de Salud , Calidad de Vida , Resultado del TratamientoRESUMEN
Huntington's disease (HD) is one of the most common, dominantly inherited neurodegenerative disorders. It affects the striatum, cerebral cortex, and other subcortical structures leading to involuntary movement abnormalities, emotional disturbances, and cognitive impairments. HD is caused by a CAGâ¢CTG trinucleotide-repeat expansion in exon 1 of the huntingtin (HTT) gene leading to the formation of mutant HTT (mtHTT) protein aggregates. Besides the toxicity of the mutated protein, there is also evidence that mtHTT transcripts contribute to the disease. Thus, the reduction of both mutated mRNA and protein would be most beneficial as a treatment. Previously, we designed a novel anti-gene oligonucleotide (AGO)-based strategy directly targeting the HTT trinucleotide-repeats in DNA and reported downregulation of mRNA and protein in HD patient fibroblasts. In this study, we differentiate HD patient-derived induced pluripotent stem cells to investigate the efficacy of the AGO, a DNA/Locked Nucleic Acid mixmer with phosphorothioate backbone, to modulate HTT transcription during neural in vitro development. For the first time, we demonstrate downregulation of HTT mRNA following both naked and magnetofected delivery into neural stem cells (NSCs) and show that neither emergence of neural rosette structures nor self-renewal of NSCs is compromised. Furthermore, the inhibition potency of both HTT mRNA and protein without off-target effects is confirmed in neurons. These results further validate an anti-gene approach for the treatment of HD.
Asunto(s)
Enfermedad de Huntington , ADN/genética , Expresión Génica , Humanos , Proteína Huntingtina/genética , Enfermedad de Huntington/genética , Enfermedad de Huntington/terapia , Oligonucleótidos , Expansión de Repetición de Trinucleótido/genéticaRESUMEN
Non-viral transfection reagents are continuously being developed in attempt to replace viral vectors. Among those non-viral vectors, dendrimers have gained increasing interest due to their unique molecular structure and multivalency. However, more improvements are still needed to achieve higher efficacy and lower toxicity. In this study, we have examined 18 peptide dendrimers conjugated to lipophilic moieties, such as fatty acids or hydrophobic amino acids, that were previously explored for siRNA. Reporter cells were employed to investigate the transfection of single strand splice-switching oligonucleotides (ONs) using these peptide dendrimers. Luciferase level changes reflecting efficiency varied with amino acid composition, stereochemistry, and complexation media used. 3rd generation peptide dendrimers with D-amino acid configuration were superior to L-form. Lead formulations with 3rd generation, D-amino acid peptide dendrimers increased the correction level of the delivered ON up to 93-fold over untreated HeLa Luc/705 cells with minimal toxicity. To stabilize the formed complexes, Polyvinyl alcohol 18 (PVA18) polymer was added. Although PVA18 addition increased activity, toxicity when using our best candidates G 2,3KL-(Leu)4 (D) and G 2,3KL-diPalmitamide (D) was observed. Our findings demonstrate the potential of lipid-conjugated, D-amino acid-containing peptide dendrimers to be utilized as an effective and safe delivery vector for splice-switching ONs.
RESUMEN
Non-viral transfection vectors are commonly used for oligonucleotide (ON) delivery but face many challenges before reaching the desired compartments inside cells. With the support of additional compounds, it might be more feasible for a vector to endure the barriers and achieve efficient delivery. In this report, we screened 18 different excipients and evaluated their effect on the performance of peptide dendrimer/lipid vector to deliver single-stranded, splice-switching ONs under serum conditions. Transfection efficiency was monitored in four different reporter cell lines by measuring splice-switching activity on RNA and protein levels. All reporter cell lines used had a mutated human ß-globin intron 2 sequence interrupting the luciferase gene, which led to an aberrant splicing of luciferase pre-mRNA and subsidence of luciferase protein translation. In the HeLa Luc/705 reporter cell line (a cervical cancer cell line), the lead excipients (Polyvinyl derivatives) potentiated the splice-switching activity up to 95-fold, compared to untreated cells with no detected cytotoxicity. Physical characterization revealed that lead excipients decreased the particle size and the zeta potential of the formulations. In vivo biodistribution studies emphasized the influence of formulations as well as the type of excipients on biodistribution profiles of the ON. Subsequently, we suggest that the highlighted impact of tested excipients would potentially assist in formulation development to deliver ON therapeutics in pre-clinical and clinical settings.
RESUMEN
The development of several different chemical modifications of nucleic acids, with improved base-pairing affinity and specificity as well as increased resistance against nucleases, has been described. These new chemistries have allowed the synthesis of different types of therapeutic oligonucleotides. Here we discuss selected chemistries used in antisense oligonucleotide (ASO) applications (e.g., small interfering RNA (siRNA), RNase H activation, translational block, splice-switching, and also as aptamers). Recently approved oligonucleotide-based drugs are also presented briefly.
Asunto(s)
Desarrollo de Medicamentos , Oligonucleótidos/química , Oligonucleótidos/farmacología , Animales , Técnicas de Química Sintética , Ensayos Clínicos como Asunto , Humanos , Ácidos Nucleicos/química , Oligonucleótidos/uso terapéutico , Relación Estructura-ActividadRESUMEN
2'-O-Methylribo phosphorothioate oligonucleotides incorporating cyclopalladated benzylamine conjugate groups at their 5'-termini have been prepared and their ability to hybridize with a designated target sequence was assessed by conventional UV melting experiments. The oligonucleotides were further examined in splice-switching experiments in human cervical cancer (HeLa Luc/705), human liver (HuH7_705), and human osteosarcoma (U-2 OS_705) reporter cell lines. Melting temperatures of duplexes formed by the modified oligonucleotides were approximately 5 °C lower than melting temperatures of the respective unmodified duplexes. The cyclopalladated oligonucleotides functioned as splice-correcting agents in the HeLa Luc/705 cell line somewhat more efficiently than their unmodified counterparts. Furthermore, the introduction of this chemical modification did not induce toxicity in cells. These results demonstrate the feasibility of using covalently metalated oligonucleotides as therapeutic agents.
Asunto(s)
Paladio/química , Oligonucleótidos Fosforotioatos/síntesis química , Empalme del ARN/efectos de los fármacos , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Complejos de Coordinación/síntesis química , Complejos de Coordinación/química , Complejos de Coordinación/farmacología , Células HeLa , Humanos , Estructura Molecular , Oligonucleótidos Fosforotioatos/química , Oligonucleótidos Fosforotioatos/farmacologíaRESUMEN
MYC, originally named c-myc, is an oncogene deregulated in many different forms of cancer. Translocation of the MYC gene to an immunoglobulin gene leads to an overexpression and the development of Burkitt's lymphoma (BL). Sporadic BL constitutes one subgroup where one of the translocation sites is located at the 5'-vicinity of the two major MYC promoters P1 and P2. A non-B-DNA forming sequence within this region has been reported with the ability to form an intramolecular triplex (H-DNA) or a G-quadruplex. We have examined triplex formation at this site first by using a 17 bp triplex-forming oligonucleotide (TFO) and a double strand DNA (dsDNA) target corresponding to the MYC sequence. An antiparallel purine-motif triplex was detected using electrophoretic mobility shift assay. Furthermore, we probed for H-DNA formation using the BQQ-OP based triplex-specific cleavage assay, which indicated the formation of the structure in the supercoiled plasmid containing the corresponding region of the MYC promoter. Targeting non-B-DNA structures has therapeutic potential; therefore, we investigated their influence on strand-invasion of anti-gene oligonucleotides (ON)s. We show that in vitro, non-B-DNA formation at the vicinity of the ON target site facilitates dsDNA strand-invasion of the anti-gene ONs.
Asunto(s)
ADN/química , Genes myc/genética , Oligonucleótidos/química , Oligodesoxirribonucleótidos , Plásmidos/química , Regiones Promotoras GenéticasRESUMEN
Locked nucleic acid (LNA) oligonucleotides bind DNA target sequences forming Watson-Crick and Hoogsteen base pairs, and are therefore of interest for medical applications. To be biologically active, such an oligonucleotide has to efficiently bind the target sequence. Here we used molecular dynamics simulations and electrophoresis mobility shift assays to elucidate the relation between helical structure and affinity for LNA-containing oligonucleotides. In particular, we have studied how LNA substitutions in the polypyrimidine strand of a duplex (thus forming a hetero duplex, i.e. a duplex with a DNA polypurine strand and an LNA/DNA polypyrimidine strand) enhance triplex formation. Based on seven polypyrimidine single strand oligonucleotides, having LNAs in different positions and quantities, we show that alternating LNA with one or more non-modified DNA nucleotides pre-organizes the hetero duplex toward a triple-helical-like conformation. This in turn promotes triplex formation, while consecutive LNAs distort the duplex structure disfavoring triplex formation. The results support the hypothesis that a pre-organization in the hetero duplex structure enhances the binding of triplex forming oligonucleotides. Our findings may serve as a criterion in the design of new tools for efficient oligonucleotide hybridization.
Asunto(s)
Conformación de Ácido Nucleico , Oligonucleótidos/química , Emparejamiento Base , Secuencia de Bases , ADN/química , Ensayo de Cambio de Movilidad Electroforética , Simulación de Dinámica MolecularRESUMEN
Despite the advances in gene therapy and in oligonucleotide (ON) chemistry, efficient cellular delivery remains an obstacle. Most current transfection reagents suffer from low efficacy or high cytotoxicity. In this report, we describe the synergism between lipid and dendrimer delivery vectors to enhance the transfection efficiency, while avoiding high toxicity. We screened a library of 20 peptide dendrimers representing three different generations and evaluated their capability to deliver a single-stranded splice-switching ON after formulating with lipids (DOTMA/DOPE). The transfection efficiency was analyzed in 5 reporter cell lines, in serum-free and serum conditions, and with 5 different formulation protocols. All formulations displayed low cytotoxicity to the majority of the tested cell lines. The complex sizes wereâ¯<â¯200â¯nm; particle size distributions of effective mixtures wereâ¯<â¯80â¯nm; and, the zeta potential was dependent on the formulation buffer used. The best dendrimer enhanced transfection in a HeLa reporter cell line by 30-fold compared to untreated cells under serum-free conditions. Interestingly, addition of sucrose to the formulation enabled - for the first time - peptide dendrimers/lipid complexes to efficiently deliver splice-switching ON in the presence of serum, reaching 40-fold increase in splice switching. Finally, in vivo studies highlighted the potential of these formulae to change the biodistribution pattern to be more towards the liver (90% of injected dose) compared to the kidneys (5% of injected dose) or to unformulated ON. This success encourages further development of peptide dendrimer complexes active in serum and future investigation of mechanisms behind the influence of additives on transfection efficacy.
Asunto(s)
Dendrímeros/química , Lípidos/química , Oligonucleótidos/administración & dosificación , Péptidos/química , Animales , Línea Celular , Femenino , Técnicas de Transferencia de Gen , Genes Reporteros/genética , Terapia Genética/métodos , Vectores Genéticos/química , Células HeLa , Humanos , Ratones , Oligonucleótidos/farmacocinética , Tamaño de la Partícula , Distribución Tisular , TransfecciónRESUMEN
BACKGROUND: A novel immunodeficiency, frequently accompanied by high serum-IgE, and caused by mutations in the PGM3 gene was described in 2014. To date there are no unique phenotype characteristics for PGM3 deficiency. PGM3 encodes a carbohydrate-modifying enzyme, phosphoglucomutase 3. Null-mutations are quite likely lethal, and to date only missense mutations or small deletions have been reported. Such mutations frequently cause a combination of reduced enzyme activity and protein instability, complicating determination of the enzyme level needed for survival. Here we present the first patient with a homozygous splice-modifying mutation in the PGM3 gene. An A > G substitution at position c.871 + 3 (transcript NM_001199917) is causing a deletion of exon 7 in the majority of PGM3 transcripts. In addition, this case further increases the clinical phenotypes of immunodeficiency caused by PGM3 mutations. CASE PRESENTATION: We describe the symptoms of a 3-year-old girl who was severely growth retarded, had vascular malformations, extensive eczema, multiple food-allergies, and was prone to infections. Unlike the majority of reported PGM3 deficient patients she lacked skeletal dysplasia and had normal neurocognitive development. In addition to the high serum-IgE, she displayed altered T cell numbers with reduced naïve CD4+ and CD8+ T-cells, increased number of activated effector memory CD8+ T cells and aberrant T-cell functions. The patient was homozygous for a new hypomorphic, splice-modifying mutation in the PGM3 gene, causing severely reduced mRNA levels. In the patient's cells, we observed 5% intact mRNA and approximately 11% of the protein levels seen in healthy controls. Treatment with allogeneic hematopoietic stem cell therapy was planned, but unfortunately the clinical condition deteriorated with multi-organ failure, which led to her death at 3 years of age. CONCLUSIONS: There is still no specific phenotype identified that distinguishes immunodeficiency caused by PGM3 mutations from other forms of immunodeficiency. The patient described here yields new information on the phenotypic variability among these patients. In addition, since all the synthesized protein is wild-type, it is possible for the first time to estimate the enzyme activity in vivo. The results suggest that1/10 of the normal PGM3 level is sufficient for survival but that it is insufficient for accurate carbohydrate processing.
Asunto(s)
Síndromes de Inmunodeficiencia/genética , Mutación , Fosfoglucomutasa/genética , Sitios de Empalme de ARN/genética , Preescolar , Resultado Fatal , Femenino , Homocigoto , Humanos , Fosfoglucomutasa/metabolismo , ARN Mensajero/metabolismoRESUMEN
The anti-gene strategy is based on sequence-specific recognition of double-strand DNA by triplex forming (TFOs) or DNA strand invading oligonucleotides to modulate gene expression. To be efficient, the oligonucleotides (ONs) should target DNA selectively, with high affinity. Here we combined hybridization analysis and electrophoretic mobility shift assay with molecular dynamics (MD) simulations to better understand the underlying structural features of modified ONs in stabilizing duplex- and triplex structures. Particularly, we investigated the role played by the position and number of locked nucleic acid (LNA) substitutions in the ON when targeting a c-MYC or FXN (Frataxin) sequence. We found that LNA-containing single strand TFOs are conformationally pre-organized for major groove binding. Reduced content of LNA at consecutive positions at the 3'-end of a TFO destabilizes the triplex structure, whereas the presence of Twisted Intercalating Nucleic Acid (TINA) at the 3'-end of the TFO increases the rate and extent of triplex formation. A triplex-specific intercalating benzoquinoquinoxaline (BQQ) compound highly stabilizes LNA-containing triplex structures. Moreover, LNA-substitution in the duplex pyrimidine strand alters the double helix structure, affecting x-displacement, slide and twist favoring triplex formation through enhanced TFO major groove accommodation. Collectively, these findings should facilitate the design of potent anti-gene ONs.
Asunto(s)
ADN/química , ADN/metabolismo , Oligonucleótidos/química , Oligonucleótidos/metabolismo , Ensayo de Cambio de Movilidad Electroforética , Genes myc , Proteínas de Unión a Hierro/genética , Simulación de Dinámica Molecular , Conformación de Ácido Nucleico , Hibridación de Ácido Nucleico , FrataxinaRESUMEN
Huntington's disease (HD) is a fatal, neurodegenerative disorder in which patients suffer from mobility, psychological and cognitive impairments. Existing therapeutics are only symptomatic and do not significantly alter the disease progression or increase life expectancy. HD is caused by expansion of the CAG trinucleotide repeat region in exon 1 of the Huntingtin gene (HTT), leading to the formation of mutant HTT transcripts (muHTT). The toxic gain-of-function of muHTT protein is a major cause of the disease. In addition, it has been suggested that the muHTT transcript contributes to the toxicity. Thus, reduction of both muHTT mRNA and protein levels would ideally be the most useful therapeutic option. We herein present a novel strategy for HD treatment using oligonucleotides (ONs) directly targeting the HTT trinucleotide repeat DNA. A partial, but significant and potentially long-term, HTT knock-down of both mRNA and protein was successfully achieved. Diminished phosphorylation of HTT gene-associated RNA-polymerase II is demonstrated, suggestive of reduced transcription downstream the ON-targeted repeat. Different backbone chemistries were found to have a strong impact on the ON efficiency. We also successfully use different delivery vehicles as well as naked uptake of the ONs, demonstrating versatility and possibly providing insights for in vivo applications.
Asunto(s)
Regulación hacia Abajo/efectos de los fármacos , Proteína Huntingtina/genética , Oligonucleótidos Fosforotioatos/farmacología , Expansión de Repetición de Trinucleótido/genética , Alelos , ADN/metabolismo , Fibroblastos/efectos de los fármacos , Fibroblastos/metabolismo , Técnicas de Silenciamiento del Gen , Humanos , Proteína Huntingtina/metabolismo , Desnaturalización de Ácido Nucleico/efectos de los fármacos , Péptidos/metabolismo , Fosforilación/efectos de los fármacos , Fosfoserina/metabolismo , ARN Polimerasa II/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Mapeo Restrictivo , Rayos UltravioletaRESUMEN
Pseudoisocytidine (ΨC) is a synthetic cytidine analogue that can target DNA duplex to form parallel triplex at neutral pH. Pseudoisocytidine has mainly two tautomers, of which only one is favorable for triplex formation. In this study, we investigated the effect of sequence on ΨC tautomerization using λ-dynamics simulation, which takes into account transitions between states. We also performed in vitro binding experiments with sequences containing ΨC and furthermore characterized the structure of the formed triplex using molecular dynamics simulation. We found that the neighboring methylated or protonated cytidine promotes the formation of the favorable tautomer, whereas the neighboring thymine or locked nucleic acid has a poor effect, and consecutive ΨC has a negative influence. The deleterious effect of consecutive ΨC in a triplex formation was confirmed using in vitro binding experiments. Our findings contribute to improving the design of ΨC-containing triplex-forming oligonucleotides directed to target G-rich DNA sequences.
RESUMEN
New advances in oligonucleotide (ON) chemistry emerge continuously, and over the last few years, several aspects of ON delivery have been improved. However, clear knowledge regarding how certain chemistries behave alone, or in combination with various delivery vectors, is limited. Moreover, characterization is frequently limited to a single reporter cell line and, when different cell types are studied, experiments are commonly not carried out under similar conditions, hampering comparative analysis. To address this, we have developed a small "tissue" library of new, stable, pLuc/705 splice-switching reporter cell lines (named HuH7_705, U-2 OS_705, C2C12_705, and Neuro-2a_705). Our data show that, indeed, the cell type used in activity screenings influences the efficiency of ONs of different chemistry (phosphorothioate with locked nucleic acid or 2'-O-methyl with or without N,N-diethyl-4-(4-nitronaphthalen-1-ylazo)-phenylamine). Likewise, the delivery method, Lipofectamine® 2000, PepFect14 nanoparticles, or "naked" uptake, also demonstrates cell-type-dependent outcomes. Taken together, these cell lines can potentially become useful tools for future in vitro evaluation of new nucleic acid-based oligomers as well as delivery compounds for splice-switching approaches and cell-specific therapies.
Asunto(s)
Hepatocitos/metabolismo , Mioblastos/metabolismo , Neuroglía/metabolismo , Oligonucleótidos/metabolismo , Osteoblastos/metabolismo , Oligonucleótidos Fosforotioatos/metabolismo , Transfección/métodos , Animales , Secuencia de Bases , Línea Celular , Péptidos de Penetración Celular/farmacología , Genes Reporteros , Vectores Genéticos/química , Vectores Genéticos/metabolismo , Células HeLa , Hepatocitos/citología , Humanos , Lípidos/farmacología , Lipopéptidos/farmacología , Luciferasas/genética , Luciferasas/metabolismo , Ratones , Mioblastos/citología , Neuroglía/citología , Oligonucleótidos/síntesis química , Especificidad de Órganos , Osteoblastos/citología , Oligonucleótidos Fosforotioatos/síntesis química , Transfección/normasRESUMEN
AS1411 is a g-quadruplex-forming aptamer capable of selectively entering cancer cells by nucleolin receptor-mediated uptake. In this study, we investigated the cell internalization properties and plasticity of AS1411 carrying different locked nucleic acid-containing cargo oligonucleotides (ONs) for delivery into A549 and U2OS cells. We found that internalization efficiency is highly governed by ON cargo chemistry and composition since the inherent antitumor properties of AS1411 were lost when attached to a nontoxic ON, noTox. However, a toxic ON, Tox, demonstrated potent cytotoxicity after aptamer-mediated uptake in A549 cells. We also examined the effect of unlocked nucleic acid (UNA) modifications in the loop region of the aptamer, and how the cargo ONs and UNA incorporation affect the secondary structure of AS1411, in the presence or absence of two novel ellipticine derivatives. These findings add new insights to the design and future applications of aptamer-guided delivery of ON cargo to cancer cells.
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Aptámeros de Nucleótidos/administración & dosificación , Sistemas de Liberación de Medicamentos , Neoplasias/tratamiento farmacológico , Oligodesoxirribonucleótidos/administración & dosificación , Células A549 , Aptámeros de Nucleótidos/efectos adversos , Aptámeros de Nucleótidos/química , Supervivencia Celular/efectos de los fármacos , Dicroismo Circular , G-Cuádruplex , Humanos , Neoplasias/genética , Oligodesoxirribonucleótidos/genética , Oligonucleótidos/administración & dosificación , Oligonucleótidos/químicaRESUMEN
Targeting and invading double-stranded DNA with synthetic oligonucleotides under physiological conditions remain a challenge. Bis-locked nucleic acids (bisLNAs) are clamp-forming oligonucleotides able to invade into supercoiled DNA via combined Hoogsteen and Watson-Crick binding. To improve the bisLNA design, we investigated its mechanism of binding. Our results suggest that bisLNAs bind via Hoogsteen-arm first, followed by Watson-Crick arm invasion, initiated at the tail. Based on this proposed hybridization mechanism, we designed next-generation bisLNAs with a novel linker able to stack to adjacent nucleobases, a new strategy previously not applied for any type of clamp-constructs. Although the Hoogsteen-arm limits the invasion, upon incorporation of the stacking linker, bisLNA invasion is significantly more efficient than for non-clamp, or nucleotide-linker containing LNA-constructs. Further improvements were obtained by substituting LNA with 2'-glycylamino-LNA, contributing a positive charge. For regular bisLNAs a 14-nt tail significantly enhances invasion. However, when two stacking linkers were incorporated, tail-less bisLNAs were able to efficiently invade. Finally, successful targeting of plasmids inside bacteria clearly demonstrates that strand invasion can take place in a biologically relevant context.