RESUMO
Targeting oncogenic transcription factor signal transducer and activator of transcription 3 (STAT3) in acute myeloid leukemia (AML) can reduce blast survival and tumor immune evasion. Decoy oligodeoxynucleotides (dODNs), which comprise STAT3-specific DNA sequences are competitive inhibition of STAT3 transcriptional activity. To deliver STAT3dODN specifically to myeloid cells, we linked STAT3dODN to the Toll-like receptor 9 (TLR9) ligand, cytosine guanine dinucleotide (CpG). The CpG-STAT3dODN conjugates are quickly internalized by human and mouse TLR9(+)immune cells (dendritic cells, B cells) and the majority of patients' derived AML blasts, including leukemia stem/progenitor cells. Following uptake, CpG-STAT3dODNs are released from endosomes, and bind and sequester cytoplasmic STAT3, thereby inhibiting downstream gene expression in target cells. STAT3 inhibition in patients' AML cells limits their immunosuppressive potential by reduced arginase expression, thereby partly restoring T-cell proliferation. Partly chemically modified CpG-STAT3dODNs have >60 hours serum half-life which allows for IV administration to leukemia-bearing mice (50% effective dose â¼ 2.5 mg/kg). Repeated administration of CpG-STAT3dODN resulted in regression of human MV4-11 AML in mice. The antitumor efficacy of this strategy is further enhanced in immunocompetent mice by combining direct leukemia-specific cytotoxicity with immunogenic effects of STAT3 blocking/TLR9 triggering. CpG-STAT3dODN effectively reducedCbfb/MYH11/MplAML burden in various organs and eliminated leukemia stem/progenitor cells, mainly through CD8/CD4 T-cell-mediated immune responses. In contrast, small-molecule Janus kinase 2/STAT3 inhibitor failed to reproduce therapeutic effects of cell-selective CpG-STAT3dODN strategy. These results demonstrate therapeutic potential of CpG-STAT3dODN inhibitors with broad implications for treatment of AML and potentially other hematologic malignancies.
Assuntos
Ilhas de CpG , Genes cdc/efeitos dos fármacos , Leucemia Mieloide Aguda , Oligodesoxirribonucleotídeos/farmacologia , Fator de Transcrição STAT3/antagonistas & inibidores , Evasão Tumoral/efeitos dos fármacos , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/imunologia , Estabilidade de Medicamentos , Genes cdc/imunologia , Terapia Genética/métodos , Humanos , Leucemia Mieloide Aguda/imunologia , Leucemia Mieloide Aguda/patologia , Leucemia Mieloide Aguda/terapia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Terapia de Alvo Molecular , Oligodesoxirribonucleotídeos/química , Oligodesoxirribonucleotídeos/uso terapêutico , Fator de Transcrição STAT3/química , Fator de Transcrição STAT3/genética , Soro/fisiologia , Transdução de Sinais/efeitos dos fármacosRESUMO
BACKGROUND: While the RNA world hypothesis is widely accepted, it is still far from complete: the existence of self-replicating ribozyme, consisting of potentially hundreds of nucleotides, is a core assumption for the majority of RNA world models. The appearance of such long RNA molecules under prebiotic conditions is not self-evident. Recombination seems to be a plausible way of creating RNA diversity, resulting in the appearance of functional RNAs, capable of self-replicating. METHODS: We report here on the study of recombination process modelled with two 96 nts RNA fragments. Detection of recombination products was performed with RT-PCR followed by TA-cloning and Sanger sequencing. RESULTS: A wide range of recombinant products was detected. We found that (i) the most efficient ligation was observed for RNA species forming bulges or internal loops, with ligation partners located within the loop; (ii) a strong preference was observed for formation of a few types of major products with a large variety of minor products; (iii) ligation could occur with participation of either 2',3'-cyclophosphate or 5'-ppp; (iv) the presence of key reaction components, i.e. 5'ppp-RNAs, enabled the formation of additional types of product; (v) molecular dynamics simulations of one of the most abundant products suggests that the ligation results in a preferable formation of 2'-5'- rather than 3'-5'-linkages. CONCLUSIONS: The study demonstrates regularities of new RNA molecules formation with non-enzymatic recombination process. GENERAL SIGNIFICANCE: Our findings provide new data supporting the RNA World hypothesis and show the way of new RNA sequences emergence under prebiotic conditions.
Assuntos
Conformação de Ácido Nucleico , RNA/química , Clonagem Molecular , HIV-1/genética , Magnésio/metabolismo , Modelos Químicos , Modelos Moleculares , Simulação de Dinâmica Molecular , Oligorribonucleotídeos/química , Origem da Vida , Plasmídeos , RNA Viral/química , Reação em Cadeia da Polimerase em Tempo Real , Análise de Sequência de RNA , Proteínas da Matriz Viral/genéticaRESUMO
STAT3 operates in both cancer cells and tumor-associated immune cells to promote cancer progression. As a transcription factor, it is a highly desirable but difficult target for pharmacologic inhibition. We have recently shown that the TLR9 agonists CpG oligonucleotides can be used for targeted siRNA delivery to mouse immune cells. In the present study, we demonstrate that a similar strategy allows for targeted gene silencing in both normal and malignant human TLR9(+) hematopoietic cells in vivo. We have developed new human cell-specific CpG(A)-STAT3 siRNA conjugates capable of inducing TLR9-dependent gene silencing and activation of primary immune cells such as myeloid dendritic cells, plasmacytoid dendritic cells, and B cells in vitro. TLR9 is also expressed by several human hematologic malignancies, including B-cell lymphoma, multiple myeloma, and acute myeloid leukemia. We further demonstrate that oncogenic proteins such as STAT3 or BCL-X(L) are effectively knocked down by specific CpG(A)-siRNAs in TLR9(+) hematologic tumor cells in vivo. Targeting survival signaling using CpG(A)-siRNAs inhibits the growth of several xenotransplanted multiple myeloma and acute myeloid leukemia tumors. CpG(A)-STAT3 siRNA is immunostimulatory and nontoxic for normal human leukocytes in vitro. The results of the present study show the potential of using tumoricidal/immunostimulatory CpG-siRNA oligonucleotides as a novel 2-pronged therapeutic strategy for hematologic malignancies.
Assuntos
Terapia Genética/métodos , Neoplasias Hematológicas/terapia , Células-Tronco Hematopoéticas/fisiologia , RNA Interferente Pequeno/farmacocinética , Receptor Toll-Like 9/genética , Animais , Linhagem Celular Tumoral , Técnicas de Transferência de Genes , Neoplasias Hematológicas/genética , Células-Tronco Hematopoéticas/patologia , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/terapia , Linfoma/genética , Linfoma/terapia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Mieloma Múltiplo/genética , Mieloma Múltiplo/terapia , Transplante de Neoplasias , Oligodesoxirribonucleotídeos/genética , RNA Interferente Pequeno/genética , Radioterapia , Fator de Transcrição STAT3/genética , Receptor Toll-Like 9/metabolismo , Transplante HeterólogoRESUMO
Tropism of neural stem cells (NSCs) to hypoxic tumor areas provides an opportunity for the drug delivery. Here, we demonstrate that NSCs effectively transport antisense oligonucleotides (ASOs) targeting oncogenic and tolerogenic signal transducer and activator of transcription 3 (STAT3) protein into glioma microenvironment. To enable spontaneous, scavenger receptor-mediated endocytosis by NSCs, we used previously described CpG-STAT3ASO conjugates. Following uptake and endosomal escape, CpG-STAT3ASO colocalized with CD63+ vesicles and later with CD63+CD81+ exosomes. Over 3 days, NSCs secreted exosomes loaded up to 80% with CpG-STAT3ASO. Compared to native NSC exosomes, the CpG-STAT3ASO-loaded exosomes potently stimulated immune activity of human dendritic cells or mouse macrophages, inducing nuclear factor κB (NF-κB) signaling and interleukin-12 (IL-12) production. Using orthotopic GL261 tumors, we confirmed that NSC-mediated delivery improved oligonucleotide transfer from a distant injection site into the glioma microenvironment versus naked oligonucleotides. Correspondingly, the NSC-delivered CpG-STAT3ASO enhanced activation of glioma-associated microglia. Finally, we demonstrated that NSC-mediated CpG-STAT3ASO delivery resulted in enhanced antitumor effects against GL261 glioma in mice. Peritumoral injections of 5 × 105 NSCs loaded ex vivo with CpG-STAT3ASO inhibited subcutaneous tumor growth more effectively than the equivalent amount of oligonucleotide alone. Based on these results, we anticipate that NSCs and NSC-derived exosomes will provide a clinically relevant strategy to improve delivery and safety of oligonucleotide therapeutics for glioma treatment.
RESUMO
Mammalian and Drosophila genomes are partitioned into topologically associating domains (TADs). Although this partitioning has been reported to be functionally relevant, it is unclear whether TADs represent true physical units located at the same genomic positions in each cell nucleus or emerge as an average of numerous alternative chromatin folding patterns in a cell population. Here, we use a single-nucleus Hi-C technique to construct high-resolution Hi-C maps in individual Drosophila genomes. These maps demonstrate chromatin compartmentalization at the megabase scale and partitioning of the genome into non-hierarchical TADs at the scale of 100 kb, which closely resembles the TAD profile in the bulk in situ Hi-C data. Over 40% of TAD boundaries are conserved between individual nuclei and possess a high level of active epigenetic marks. Polymer simulations demonstrate that chromatin folding is best described by the random walk model within TADs and is most suitably approximated by a crumpled globule build of Gaussian blobs at longer distances. We observe prominent cell-to-cell variability in the long-range contacts between either active genome loci or between Polycomb-bound regions, suggesting an important contribution of stochastic processes to the formation of the Drosophila 3D genome.
Assuntos
Drosophila melanogaster/genética , Genoma de Inseto , Conformação de Ácido Nucleico , Animais , Biopolímeros/metabolismo , Cromatina/genética , Bases de Dados Genéticas , Epigênese Genética , Haploidia , Modelos Genéticos , Processos Estocásticos , Cromossomo X/genéticaAssuntos
Aptâmeros de Nucleotídeos/farmacologia , MicroRNAs/genética , MicroRNAs/farmacologia , Neoplasias/patologia , Neoplasias/terapia , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Animais , Feminino , Humanos , Masculino , Receptor Tirosina Quinase AxlRESUMO
RNA non-enzymatic recombination reactions are of great interest within the hypothesis of the "RNA world", which argues that at some stage of prebiotic life development proteins were not yet engaged in biochemical reactions and RNA carried out both the information storage task and the full range of catalytic roles necessary in primitive self-replicating systems. Here we report on the study of recombination reaction occuring between two 96 nucleotides (nts) fragments of RNAs under physiological conditions and governed by a short oligodeoxyribonucleotide template, partially complementary to sequences within each of the RNAs. Analysis of recombination products shows that ligation is predominantly template-directed, and occurs within the complementary complex with the template in "butt-to-butt" manner, in 1- or 3- nts bulges or in 2-3 nts internal loops. Minor recombination products formed in the template-independent manner are detected as well.
Assuntos
RNA/metabolismo , Sequência de Bases , HIV/genética , Humanos , Vírus da Influenza A/genética , Vírus da Influenza A/metabolismo , Modelos Genéticos , RNA/genética , RNA Viral/genética , RNA Viral/metabolismo , Recombinação Genética , Moldes Genéticos , Proteínas da Matriz Viral/genéticaRESUMO
The SiRNA strategy is a potent and versatile method for modulating expression of any gene in various species for investigational or therapeutic purposes. Clinical translation of SiRNA-based approaches proved challenging, mainly due to the difficulty of targeted SiRNA delivery into cells of interest and the immunogenic side effects of oligonucleotide reagents. However, the intrinsic sensitivity of immune cells to nucleic acids can be utilized for the delivery of SiRNAs designed for the purpose of cancer immunotherapy. We have demonstrated that synthetic ligands for the intracellular receptor TLR9 can serve as targeting moiety for cell-specific delivery of SiRNAs. Chemically synthesized CpG-SiRNA conjugates are quickly internalized by TLR9-positive cells in the absence of transfection reagents, inducing target gene silencing. The CpG-SiRNA strategy allows for effective targeting of TLR9-positive cells in vivo after local or systemic administration of these oligonucleotides into mice.
Assuntos
Sistemas de Liberação de Medicamentos/métodos , RNA Interferente Pequeno/metabolismo , Receptor Toll-Like 9/metabolismo , Animais , Sequência de Bases , Células da Medula Óssea/citologia , Células da Medula Óssea/metabolismo , Linhagem Celular Tumoral , Separação Celular , Ilhas de CpG , Citometria de Fluxo , Inativação Gênica , Humanos , Camundongos , Hibridização de Ácido Nucleico , Oligonucleotídeos/química , Oligonucleotídeos/genética , Oligonucleotídeos/metabolismo , RNA Interferente Pequeno/química , RNA Interferente Pequeno/genéticaRESUMO
Prostate cancer progression was associated with tumorigenic signaling activated by proinflammatory mediators. However, the etiology of these events remains elusive. Here, we demonstrate that triggering of the innate immune receptor, Toll-like Receptor 9 (TLR9), in androgen-independent prostate cancer cells initiates signaling cascade leading to increased tumor growth and progression. Using limited dilution/serial transplantation experiments, we show that TLR9 is essential for prostate cancer cells' potential to propagate and self-renew in vivo. Furthermore, low expression or silencing of TLR9 limits the clonogenic potential and mesenchymal stem cell-like properties of LNCaP- and PC3-derived prostate cancer cell variants. Genome-wide transcriptional analysis of prostate cancer cells isolated from xenotransplanted TLR9-positive and -negative tumors revealed a unique gene expression signature, with prominent upregulation of inflammation- and stem cell-related markers. TLR9 signaling orchestrated expression of critical stem cell-related genes such as NKX3.1, KLF-4, BMI-1 and COL1A1, at both mRNA and protein levels. Our further analysis identified that TLR9-induced NF-κB/RELA and STAT3 transcription factors co-regulated NKX3.1 and KLF4 gene expression by directly binding to both promoters. Finally, we demonstrated the feasibility of using TLR9-targeted siRNA delivery to block RELA- and STAT3-dependent prostate cancer cell self-renewal in vivo. The intratumoral administration of CpG-RELAsiRNA or CpG-STAT3siRNA but not control conjugates inhibited growth of established prostate tumors and reduced clonogenic potential of cancer cells. Overcoming cancer cell self-renewal and tumor-propagating potential by targeted inhibition of TLR9 signaling can provide therapeutic strategy for late-stage prostate cancer patients.
Assuntos
Regulação Neoplásica da Expressão Gênica/fisiologia , Neoplasias da Próstata/patologia , Transdução de Sinais/fisiologia , Receptor Toll-Like 9/metabolismo , Animais , Western Blotting , Linhagem Celular Tumoral , Imunoprecipitação da Cromatina , Citometria de Fluxo , Xenoenxertos , Humanos , Fator 4 Semelhante a Kruppel , Masculino , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , NF-kappa B/metabolismo , Neoplasias da Próstata/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Fator de Transcrição STAT3/metabolismo , Fator de Transcrição RelA/metabolismoRESUMO
Dicer-substrate siRNAs equipped with CpG oligodeoxyribonucleotides overcome the major hurdle in cell-specific siRNA delivery. The CpG-siRNA molecules are actively internalized by TLR9+ cells, without the need for transfection reagents, leading to RNA interference both in vitro and in vivo. Here, we elucidate the molecular mechanisms of CpG-siRNA processing in target cells. We show that shortly after uptake into early endosomes (EE), CpG and siRNA parts of the conjugate are uncoupled in the presence of Dicer endonuclease. Diced siRNA molecules are translocated from endosomes to endoplasmic reticulum, where they can interact with the RNA interference machinery. We previously observed that even though TLR9 is not involved in CpG-siRNA uptake, it is indispensable for induction of gene silencing. To explain the role of TLR9 in intracellular processing of CpG-siRNA, we used primary macrophages derived from wild-type and Tlr9-deficient mice. Macrophages lacking TLR9 showed extended endosomal colocalization of CpG and siRNA parts of the conjugate. However, Tlr9 ablation did not interfere with the interaction of CpG-siRNA with Dicer as shown by in situ proximity ligation assay. Using CpG-siRNA labeled with pH-sensitive dye, we finally identified that lack of TLR9 in macrophages resulted in significant retention of the siRNA in endosomes. Thus, TLR9 facilitates the critical step following CpG-siRNA uncoupling, which is cytoplasmic release of the diced siRNA. These findings suggest that the class of immunostimulatory siRNAs may benefit from activation of certain endosomal immune receptors, such as TLR9, in augmented gene silencing and therapeutic efficacy.
Assuntos
Ilhas de CpG , RNA Interferente Pequeno/genética , Receptor Toll-Like 9/genética , Animais , Linhagem Celular , Linhagem Celular Tumoral , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fator de Transcrição STAT3/genética , Receptor Toll-Like 9/deficiênciaRESUMO
Cancer radiotherapy may be immunogenic, but it is unclear why its immunogenic effects are rarely sufficient to prevent tumor recurrence. Here, we report a novel Toll-like receptor 9 (TLR9)-dependent mechanism that initiates tumor regrowth after local radiotherapy. Systemic inhibition of TLR9, but not TLR4, delayed tumor recurrence in mouse models of B16 melanoma, MB49 bladder cancer, and CT26 colon cancer after localized high-dose tumor irradiation. Soluble factors in the microenvironment of regressing tumors triggered TLR9 signaling in freshly recruited myeloid cells appearing within four days of radiotherapy. The tumorigenic effects of TLR9 depended on MyD88/NF-κB-mediated upregulation of interleukin (IL)-6 expression, which in turn resulted in downstream activation of Jak/STAT3 signaling in myeloid cells. In comparing global gene expression in wild-type, TLR9-, or STAT3-deficient myeloid cells derived from irradiated tumors, we identified a unique set of TLR9/STAT3-regulated genes involved in tumor-promoting inflammation and revascularization. Blocking STAT3 function by two myeloid-specific genetic strategies corrected TLR9-mediated cancer recurrence after radiotherapy. Our results suggest that combining localized tumor irradiation with myeloid cell-specific inhibition of TLR9/STAT3 signaling may help eliminate radioresistant cancers.