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1.
Int J Mol Sci ; 25(17)2024 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-39273414

RESUMO

As the most common and aggressive primary malignant brain tumor, glioblastoma is still lacking a satisfactory curative approach. The standard management consisting of gross total resection followed by radiotherapy and chemotherapy with temozolomide only prolongs patients' life moderately. In recent years, many therapeutics have failed to give a breakthrough in GBM treatment. In the search for new treatment solutions, we became interested in the repurposing of existing medicines, which have established safety profiles. We focused on the possible implementation of well-known drugs, metformin, and arginine. Metformin is widely used in diabetes treatment, but arginine is mainly a cardiovascular protective drug. We evaluated the effects of metformin and arginine on total DNA methylation, as well as the oxidative stress evoked by treatment with those agents. In glioblastoma cell lines, a decrease in 5-methylcytosine contents was observed with increasing drug concentration. When combined with temozolomide, both guanidines parallelly increased DNA methylation and decreased 8-oxo-deoxyguanosine contents. These effects can be explained by specific interactions of the guanidine group with m5CpG dinucleotide. We showed that metformin and arginine act on the epigenetic level, influencing the foreground and potent DNA regulatory mechanisms. Therefore, they can be used separately or in combination with temozolomide, in various stages of disease, depending on desired treatment effects.


Assuntos
Arginina , Metilação de DNA , Reposicionamento de Medicamentos , Glioblastoma , Metformina , Temozolomida , Metformina/farmacologia , Metformina/uso terapêutico , Glioblastoma/tratamento farmacológico , Glioblastoma/metabolismo , Humanos , Arginina/metabolismo , Reposicionamento de Medicamentos/métodos , Metilação de DNA/efeitos dos fármacos , Linhagem Celular Tumoral , Temozolomida/uso terapêutico , Temozolomida/farmacologia , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Epigênese Genética/efeitos dos fármacos , 5-Metilcitosina/metabolismo , 5-Metilcitosina/análogos & derivados
2.
Int J Mol Sci ; 24(8)2023 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-37108161

RESUMO

Glioblastoma (GBM) is the most common and aggressive primary brain tumor and one of the human malignancies with the highest mortality. Standard approaches for GBM, including gross total resection, radiotherapy, and chemotherapy, cannot destroy all the cancer cells, and despite advances in its treatment, the prognosis for GBM remains poor. The problem is that we still do not understand what triggers GBM. Until now, the most successful chemotherapy with temozolomide for brain gliomas is not effective, and therefore new therapeutic strategies for GBM are needed. We found that juglone (J), which exhibits cytotoxic, anti-proliferative, and anti-invasive effects on various cells, could be a promising agent for GBM therapy. In this paper, we present the effects of juglone alone and in combination with temozolomide on glioblastoma cells. In addition to the analysis of cell viability and the cell cycle, we looked at the epigenetics effects of these compounds on cancer cells. We showed that juglone induces strong oxidative stress, as identified by a high increase in the amount of 8-oxo-dG, and decreases m5C in the DNA of cancer cells. In combination with TMZ, juglone modulates the level of both marker compounds. Our results strongly suggest that a combination of juglone and temozolomide can be applied for better GBM treatment.


Assuntos
Neoplasias Encefálicas , Glioblastoma , Humanos , Temozolomida/farmacologia , Temozolomida/uso terapêutico , Glioblastoma/tratamento farmacológico , Glioblastoma/genética , Glioblastoma/patologia , Linhagem Celular Tumoral , Epigênese Genética , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Resistencia a Medicamentos Antineoplásicos/genética , Antineoplásicos Alquilantes/farmacologia
3.
Int J Mol Sci ; 24(4)2023 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-36834975

RESUMO

Ageing and deterioration of seeds is a major problem for the maintenance of seed quality and viability during long-term storage. Prediction of early stages of seed deterioration in order to point out the plantlets' regeneration time is a major challenge of successful storage. In preserved seeds, damages accumulate within cells at the rate mainly related to their moisture content and temperature of storage. Current research reveals global alterations in DNA methylation in lipid-rich intermediate seeds during desiccation and storage at various regimes covering nonoptimal and optimal conditions. We show for the first time that monitoring of 5-methylcytosine (m5C) level in seeds can be used as a truly universal viability marker regardless of postharvest category of seeds and their composition. For seeds stored up to three years, in varied conditions, moisture content, temperature, and time of storage had significant influence on seedling emergence and DNA methylation (p < 0.05). Similarities among lipid-rich intermediate and orthodox seeds regarding different reactions of embryonic axes and cotyledons to desiccation are newly revealed. Along with previous studies on seeds dramatically different in desiccation tolerance (recalcitrant vs. orthodox), results regarding lipid-rich seeds positioned in-between (intermediate) prove that maintaining global DNA methylation status is crucial for maintaining seed viability.


Assuntos
Metilação de DNA , Fagus , Dessecação , Sementes/genética , Lipídeos , Germinação
4.
Front Oncol ; 12: 1033035, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36465345

RESUMO

Currently, valproic acid (VPA) is known as an inhibitor of histone deacetylase (epigenetic drug) and is used for the clinical treatment of epileptic events in the course of glioblastoma multiforme (GBM). Which improves the clinical outcome of those patients. We analyzed the level of 5-methylcytosine, a DNA epigenetic modulator, and 8-oxodeoxyguanosine, an cellular oxidative damage marker, affected with VPA administration, alone and in combination with temozolomide (TMZ), of glioma (T98G, U118, U138), other cancer (HeLa), and normal (HaCaT) cell lines. We observed the VPA dose-dependent changes in the total DNA methylation in neoplastic cell lines and the lack of such an effect in a normal cell line. VPA at high concentrations (250-500 µM) induced hypermethylation of DNA in a short time frame. However, the exposition of GBM cells to the combination of VPA and TMZ resulted in DNA hypomethylation. At the same time, we observed an increase of genomic 8-oxo-dG, which as a hydroxyl radical reaction product with guanosine residue in DNA suggests a red-ox imbalance in the cancer cells and radical damage of DNA. Our data show that VPA as an HDAC inhibitor does not induce changes only in histone acetylation, but also changes in the state of DNA modification. It shows cross-reactivity between chromatin remodeling due to histone acetylation and DNA methylation. Finally, total DNA cytosine methylation and guanosine oxidation changes in glioma cell lines under VPA treatment suggest a new epigenetic mechanism of that drug action.

5.
Postepy Biochem ; 68(2): 169-178, 2022 06 30.
Artigo em Polonês | MEDLINE | ID: mdl-35792642

RESUMO

The year 1961 went down in history with exceptional scientific achievements. On May 13, the journal Nature published two articles on the first isolation of messenger ribonucleic acid (mRNA), which is an intermediate product between a gene and a protein. Just two weeks later, on May 27, the first letter of the genetic code, phenylalanine, was discovered. These discoveries made it possible to understand how genetic information is encoded and processed, thus causing the dynamic development of molecular biology. The breakthroughs of 1961 concerned not only nucleic acids. On April 12, the first human, Yuri Gagarin, entered space. Eight years later, in 1969, Neil Armstrong made his first walk on the moon, uttering the famous phrase: It is a small step for man, but a great leap for humanity. The era of conquering and learning about the cosmos has begun, mainly motivated by the natural curiosity of man and the desire to learn about the surrounding reality. The environmental factors in space are very different from terrestrial conditions, which raises questions about their effects on living organisms. In search of answers, a variety of scientific research has been carried out at the International Space Station (ISS) for over twenty years. As space travel is set to become more common in the near future, detailed studies of the effects of long-term space missions on the human body are required. These studies are currently carried out, among others using molecular biology techniques that enable detailed analysis of nucleic acids and proteins, but not only. The breakthrough achievements of 1961 initiated the development both in the field of molecular biology and the science of space, thanks to which today, 60 years after those events, we can combine knowledge and technological achievements from both fields to analyze and understand changes at the molecular level that occur as a result of being in organisms in outer space.


Assuntos
Ácidos Nucleicos , Voo Espacial , Epigênese Genética , Humanos , Masculino
6.
Cells ; 11(13)2022 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-35805164

RESUMO

Ex situ preservation of genetic resources is an essential strategy for the conservation of plant biodiversity. In this regard, seed storage is the most convenient and efficient way of preserving germplasm for future plant breeding efforts. A better understanding of the molecular changes that occur during seed desiccation and aging is necessary to improve conservation protocols, as well as real-time methods for monitoring seed quality. In the present study, we assessed changes in the level of genomic 5-methylcytosine (5mC) in seeds of Populus nigra L. by 2D-TLC. Epigenetic changes were characterized in response to several seed storage regimes. Our results demonstrate that P. nigra seeds represent an intermediate type of post-harvest behavior, falling between recalcitrant and orthodox seeds. This was also true for the epigenetic response of P. nigra seeds to external factors. A crucial question is whether aging in seeds is initiated by a decline in the level of 5mC, or if epigenetic changes induce a process that leads to deterioration. In our study, we demonstrate for the first time that 5mC levels decrease during storage and that the decline can be detected before any changes in seed germination are evident. Once P. nigra seeds reached an 8-10% reduction in the level of 5mC, a substantial decrease in germination occurred. The decline in the level of 5mC appears to be a critical parameter underlying the rapid deterioration of intermediate seeds. Thus, the measurement of 5mC can be a fast, real-time method for assessing asymptomatic aging in stored seeds.


Assuntos
Metilação de DNA , Populus , Metilação de DNA/genética , Germinação , Plantas , Populus/genética , Sementes/genética
7.
J Biomol Struct Dyn ; 40(7): 3038-3045, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-33200684

RESUMO

A new mechanism of RNA circularization driven by specific binding of miRNAs is described. We identified the 71 CUUCC pentanucleotide motifs distributed regularly throughout the entire molecule of CDR1as RNA that bind to 71 miRNAs through their seed sequence GGAAG. The sequential binding of miR-7 RNAs (71 molecules) brings both ends of CDR1as RNA (1 molecule) together and stimulate phosphodiester bond formation between nucleotides C1 and A1299 at the 5' and 3' end, respectively. The binding of miRNAs to CDR1as RNA results in the unique complex formation, which shows three specific structural domains: (i) two short helixes with an internal loop, (ii) the hinge, and (iii) the triple-helix. The proposed mechanism explains specific RNA circularization and its function as a miRNAs sponge. Furthermore, the existing wet experimental data on the interaction of CDR1as RNA with miR-7 fully supports our observation. Although miR-671 shows the same seed sequence as miR-7, it forms an almost perfect double helix with CDR1as RNA and induces the cleavage of CDR1as, but does not stimulate circularization. To check how common is the proposed mechanism among circular RNAs, we analyzed the most recent circAtlas database counting almost 1.1 million sequences. It turned out that there are a huge number of circRNAs, which showed miRNAs seed binding sequences distributed through the whole circRNA sequences and prove that circularization of linear transcript is miRNA dependent.Communicated by Ramaswamy H. Sarma.


Assuntos
MicroRNAs , MicroRNAs/genética , MicroRNAs/metabolismo , RNA/genética , RNA/metabolismo , RNA Circular/genética
8.
Postepy Biochem ; 67(3): 212-222, 2021 09 30.
Artigo em Polonês | MEDLINE | ID: mdl-34894389

RESUMO

The year 2021 marks not only 60 years since the discovery of messenger RNA and the genetic code. Already 100 yaers passed since RNA was discovered. On the occasion of this special anniversary, we would like to recall the most important events in the history of nucleic acids that led to the above discoveries. We remind the beginning of a new era in science caused by the isolation of nuclein and then nucleic acid, whose components and properties were gradually learned, often by little-known researchers. The distinction of RNA and DNA and the analysis of their occurrence in cells made it possible to formulate the first conclusions about the functions of these compounds. Conclusions on the ratio of nitrogenous bases in DNA led to the knowledge of the structure of the double helix, triggering an avalanche of questions about the essence of transmission of genetic information. Answers began to emerge with the discovery of mRNA, and knowledge of the first three nucleotides encoding an amino acid caused a race to decipher the genetic code. The above discoveries are the foundation of molecular biology. The diamond jubilee coincided with the development of an mRNA-based vaccine against the SARS-CoV-2.


Assuntos
COVID-19 , RNA , DNA , Humanos , RNA/genética , RNA Mensageiro/genética , SARS-CoV-2
9.
Cancers (Basel) ; 12(7)2020 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-32629974

RESUMO

Cellular senescence is a tumor-suppressive mechanism blocking cell proliferation in response to stress. However, recent evidence suggests that senescent tumor cells can re-enter the cell cycle to become cancer stem cells, leading to relapse after cancer chemotherapy treatment. Understanding how the senescence reprogramming process is a precursor to cancer stem cell formation is of great medical importance. To study the interplay between senescence, stemness, and cancer, we applied a stem cell medium (SCM) to human embryonic fibroblasts (MRC5 and WI-38) and cancer cell lines (A549 and 293T). MRC5 and WI-38 cells treated with SCM showed symptoms of oxidative stress and became senescent. Transcriptome analysis over a time course of SCM-induced senescence, revealed a developmental process overlapping with the upregulation of genes for growth arrest and the senescence-associated secretory phenotype (SASP). We demonstrate that histone demethylases jumonji domain-containing protein D3 (Jmjd3) and ubiquitously transcribed tetratricopeptide repeat, X chromosome (Utx), which operate by remodeling chromatin structure, are implicated in the senescence reprogramming process to block stem cell formation in fibroblasts. In contrast, A549 and 293T cells cultured in SCM were converted to cancer stem cells that displayed the phenotype of senescence uncoupled from growth arrest. The direct overexpression of DNA methyltransferases (Dnmt1 and Dnmt3A), ten-eleven translocation methylcytosine dioxygenases (Tet1 and Tet3), Jmjd3, and Utx proteins could activate senescence-associated beta-galactosidase (SA-ß-gal) activity in 293T cells, suggesting that epigenetic alteration and chromatin remodeling factors trigger the senescence response. Overall, our study suggests that chromatin machinery controlling senescence reprogramming is significant in cancer stem cell formation.

10.
Cells ; 8(9)2019 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-31514401

RESUMO

DNA modifications can be used to monitor pathological processes. We have previously shown that estimating the amount of the main DNA epigenetic mark, 5-methylcytosine (m5C), is an efficient and reliable way to diagnose brain tumors, hypertension, and other diseases. Abnormal increases of reactive oxygen species (ROS) are a driving factor for mutations that lead to changes in m5C levels and cancer evolution. 8-oxo-deoxyguanosine (8-oxo-dG) is a specific marker of ROS-driven DNA-damage, and its accumulation makes m5C a hotspot for mutations. It is unknown how m5C and 8-oxo-dG correlate with the malignancy of gliomas. We analyzed the total contents of m5C and 8-oxo-dG in DNA from tumor tissue and peripheral blood samples from brain glioma patients. We found an opposite relationship in the amounts of m5C and 8-oxo-dG, which correlated with glioma grade in the way that low level of m5C and high level of 8-oxo-dG indicated increased glioma malignancy grade. Our results could be directly applied to patient monitoring and treatment protocols for gliomas, as well as bolster previous findings, suggesting that spontaneously generated ROS react with m5C. Because of the similar mechanisms of m5C and guanosine oxidation, we concluded that 8-oxo-dG could also predict glioma malignancy grade and global DNA demethylation in cancer cells.


Assuntos
5-Metilcitosina/metabolismo , 8-Hidroxi-2'-Desoxiguanosina/metabolismo , Neoplasias Encefálicas/metabolismo , DNA/metabolismo , Glioma/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/metabolismo , Dano ao DNA , Metilação de DNA , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismo , Adulto Jovem
11.
Tree Physiol ; 38(4): 617-629, 2018 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-29121348

RESUMO

Poor storability of recalcitrant seeds is due to their inability to tolerate low moisture content. Understanding the processes underlying their recalcitrance is a prerequisite to developing a maintenance strategy and prolonging their lifespan. Multiple studies have investigated the differences between orthodox (desiccation-tolerant) and recalcitrant (desiccation-sensitive) seeds. Information on epigenetic regulation, however, is lacking and thus limits our understanding of the processes defining the physiology of seeds. In the present comparative study, changes in the global levels of 5-methylcytosine (m5C) in orthodox and recalcitrant seeds of Acer platanoides L. and Acer pseudoplatanus L. were characterized during progressive stages of severe drying. Concomitant with their differential sensitivity to desiccation stress, we demonstrate variation in the response of embryonic axes and cotyledons to water deficit at the level of DNA methylation. Results indicate that desiccation-induced changes in m5C are both tissue- and seed category-specific and are highly correlated with recalcitrant seed viability. Moreover, we demonstrate that m5C global changes in response to desiccation are not retained in DNA isolated from seedlings, except in seedlings that are derived from strongly desiccated orthodox seeds (moisture content of 3.5%). Finally, the potential utilization of m5C status as a universal seed viability marker is discussed.


Assuntos
5-Metilcitosina/metabolismo , Acer/genética , Acer/metabolismo , Metilação de DNA , Dessecação , Genoma de Planta , Epigênese Genética , Plântula/genética , Plântula/metabolismo , Sementes/genética , Sementes/metabolismo , Especificidade da Espécie
12.
Sci Rep ; 6: 24516, 2016 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-27079911

RESUMO

Despite tremendous efforts worldwide, glioblastoma multiforme (GBM) remains a deadly disease for which no cure is available and prognosis is very bad. Recently, miR-21 has emerged as a key omnipotent player in carcinogenesis, including brain tumors. It is recognized as an indicator of glioma prognosis and a prosperous target for anti-tumor therapy. Here we show that rationally designed hammerhead ribozymes and DNAzymes can target miR-21 and/or its precursors. They decrease miR-21 level, and thus silence this oncomiR functions. We demonstrated that anti-miRNA catalytic nucleic acids show a novel terrific arsenal for specific and effective combat against diseases with elevated cellular miR-21 content, such as brain tumors.


Assuntos
Neoplasias Encefálicas/genética , DNA Catalítico/genética , Regulação Neoplásica da Expressão Gênica , Glioma/genética , MicroRNAs/genética , RNA Catalítico/genética , Linhagem Celular Tumoral , Humanos , Hidrólise
13.
PLoS One ; 10(8): e0136669, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26309255

RESUMO

Temozolomide (TMZ) is an oral alkylating chemotherapeutic agent that prolongs the survival of patients with glioblastoma (GBM). Despite that high TMZ potential, progression of disease and recurrence are still observed. Therefore a better understanding of the mechanism of action of this drug is necessary and may allow more durable benefit from its anti-glioma properties. Using nucleotide post-labelling method and separation on thin-layer chromatography we measured of global changes of 5-methylcytosine (m5C) in DNA of glioma cells treated with TMZ. Although m5C is not a product of TMZ methylation reaction of DNA, we analysed the effects of the drug action on different glioma cell lines through global changes at the level of the DNA main epigenetic mark. The first effect of TMZ action we observed is DNA hypermethylation followed by global demethylation. Therefore an increase of DNA methylation and down regulation of some genes expression can be ascribed to activation of DNA methyltransferases (DNMTs). On the other hand hypomethylation is induced by oxidative stress and causes uncontrolled expression of pathologic protein genes. The results of brain tumours treatment with TMZ suggest the new mechanism of modulation epigenetic marker in cancer cells. A high TMZ concentration induced a significant increase of m5C content in DNA in the short time, but a low TMZ concentration at longer time hypomethylation is observed for whole range of TMZ concentrations. Therefore TMZ administration with low doses of the drug and short time should be considered as optimal therapy.


Assuntos
Antineoplásicos Alquilantes/farmacologia , Neoplasias Encefálicas/tratamento farmacológico , Metilação de DNA/efeitos dos fármacos , Dacarbazina/análogos & derivados , Epigênese Genética , Glioma/tratamento farmacológico , 5-Metilcitosina/química , Animais , Neoplasias Encefálicas/genética , Linhagem Celular Tumoral , DNA/química , Dacarbazina/farmacologia , Glioma/patologia , Células HeLa , Humanos , Estresse Oxidativo/efeitos dos fármacos , Ratos , Temozolomida
14.
Ann Bot ; 116(3): 369-76, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26133690

RESUMO

BACKGROUND AND AIMS: Epigenetic regulation plays an important role in the management of plant growth, development and response to stress factors, and several reports have indicated that DNA methylation plays a critical role in seed development and viability. This study examines changes in 5-methylcytosine (m(5)C) levels in the DNA of seeds during ageing, a process that has important implications for plant conservation and agriculture. METHODS: Changes in the global level of m(5)C were measured in mature seeds of oak, Quercus robur. The extent of DNA methylation was measured using a protocol based on two-dimensional thin-layer chromatography. Viability of seeds was determined by germination and seedling emergence tests. KEY RESULTS: An ageing-related decrease in total m(5)C during storage of recalcitrant seeds was highly and significantly correlated with a decrease in seed viability, as reflected by a reduction in germination (r = 0·8880) and seedling emergence (r = 0·8269). CONCLUSIONS: The decrease in viability during ageing of Q. robur seeds is highly correlated with a global decline in the amount of m(5)C in genomic DNA, and it is possible that this may represent a typical response to ageing and senescence in recalcitrant seeds. Potential mechanisms that drive changes in genomic DNA methylation during ageing are discussed, together with their implications for seed viability.


Assuntos
5-Metilcitosina/metabolismo , Epigênese Genética , Quercus/genética , Metilação de DNA , Quercus/crescimento & desenvolvimento , Quercus/metabolismo , Sementes/genética , Sementes/crescimento & desenvolvimento , Sementes/metabolismo
15.
Mol Oncol ; 9(7): 1324-40, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25864039

RESUMO

Malignant gliomas represent the most devastating group of brain tumors in adults, among which glioblastoma multiforme (GBM) exhibits the highest malignancy rate. Despite combined modality treatment, GBM recurs and is invariably fatal. A further insight into the molecular background of gliomagenesis is required to improve patient outcomes. The primary aim of this study was to gain broad information on the miRNA expression pattern in malignant gliomas, mainly GBM. We investigated the global miRNA profile of malignant glioma tissues with miRNA microarrays, deep sequencing and meta-analysis. We selected miRNAs that were most frequently deregulated in glioblastoma tissues, as well as in peritumoral areas, in comparison with normal human brain. We identified candidate miRNAs associated with the progression from glioma grade III to glioma grade IV. The meta-analysis of miRNA profiling studies in GBM tissues summarizes the past and recent advances in the investigation of the miRNA signature in GBM versus noncancerous human brain and provides a comprehensive overview. We propose a list of 35 miRNAs whose expression is most frequently deregulated in GBM patients and of 30 miRNA candidates recognized as novel GBM biomarkers.


Assuntos
Perfilação da Expressão Gênica , Glioblastoma/genética , MicroRNAs/genética , Biomarcadores/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala , Humanos
16.
PLoS One ; 9(11): e113848, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25423301

RESUMO

The generally accepted model of the miRNA-guided RNA down-regulation suggests that mature miRNA targets mRNA in a nucleotide sequence-specific manner. However, we have shown that the nucleotide sequence of miRNA is not the only determinant of miRNA specificity. Using specific nucleases, T1, V1 and S1 as well as NMR, UV/Vis and CD spectroscopies, we found that miR-21, miR-93 and miR-296 can adopt hairpin and/or homoduplex structures. The secondary structure of those miRNAs in solution is a function of RNA concentration and ionic conditions. Additionally, we have shown that a formation of miRNA hairpin is facilitated by cellular environment.Looking for functional consequences of this observation, we have perceived that structure of these miRNAs resemble RNA aptamers, short oligonucleotides forming a stable 3D structures with a high affinity and specificity for their targets. We compared structures of anti-tenascin C (anti-Tn-C) aptamers, which inhibit brain tumor glioblastoma multiforme (GBM, WHO IV) and selected miRNA. A strong overexpression of miR-21, miR-93 as well Tn-C in GBM may imply some connections between them. The structural similarity of these miRNA hairpins and anti-Tn-C aptamers indicates that miRNAs may function also beyond RISC and are even more sophisticated regulators, that it was previously expected. We think that the knowledge of the miRNA structure may give a new insight into miRNA-dependent gene regulation mechanism and be a step forward in the understanding their function and involvement in cancerogenesis. This may improve design process of anti-miRNA therapeutics.


Assuntos
MicroRNAs/química , Conformação de Ácido Nucleico , Sequência de Bases , Humanos , MicroRNAs/genética , Homologia de Sequência do Ácido Nucleico
17.
PLoS One ; 9(3): e92599, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24651295

RESUMO

There are no good blood and serum biomarkers for detection, follow up, or prognosis of brain tumors. However, they are needed for more detailed tumor classification, better prognosis estimation and selection of an efficient therapeutic strategy. The aim of this study was to use the epigenetic changes in DNA of peripheral blood samples as a molecular marker to diagnose brain tumors as well as other diseases. We have applied a very precise thin-layer chromatography (TLC) analysis of the global amount of 5-methylcytosine (m(5)C) in DNA from brain tumors, colon and breast cancer tissues and peripheral blood samples of the same patients. The m(5)C level in tissue DNA from different brain tumor types, expressed as R coefficient, changes within the range of 0.2-1.6 and overlaps with R of that of blood samples. It negatively correlates with the WHO malignancy grade. The global DNA hypomethylation quantitative measure in blood, demonstrates a big potential for development of non-invasive applications for detection of a low and a high grade brain tumors. We have also used this approach to analyze patients with breast and colon cancers. In all these cases the m(5)C amount in DNA cancer tissue match with data of blood. This study is the first to demonstrate the potential role of global m(5)C content in blood DNA for early detection of brain tumors and others diseases. So, genomic DNA hypomethylation is a promising marker for prognosis of various neoplasms as well as other pathologies.


Assuntos
Biomarcadores Tumorais , Metilação de DNA , Neoplasias/genética , 5-Metilcitosina/sangue , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Encefálicas/sangue , Neoplasias Encefálicas/genética , Epigênese Genética , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias/sangue , Adulto Jovem
18.
Eur J Med Chem ; 55: 243-54, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22854677

RESUMO

DNA cytosine methylation catalyzed by DNA methyltransferase 1 (DNMT1) is an epigenetic method of gene expression regulation and development. Changes in methylation pattern lead to carcinogenesis. Inhibition of DNMT1 activity could be a good strategy of safe and efficient epigenetic therapy. In this work, we present a novel group of cytosine analogs as inhibitors of DNA methylation. We show new methods of synthesis and their effect on in vitro reaction of DNA methylation. Almost all of analyzed compounds inhibit DNA methyltransferase activity in the competitive manner. K(i) values for the most potent compound 4-N-furfuryl-5,6-dihydroazacytosines is 0.7 µM. These compounds cause also a decrease of 5-methylcytosine (m(5)C) level in DNA of mammalian HeLa and HEK293 cells.


Assuntos
Citosina/análogos & derivados , Citosina/farmacologia , Metilação de DNA/efeitos dos fármacos , Técnicas de Química Sintética , Citosina/síntese química , Células HEK293 , Células HeLa , Humanos
19.
Przegl Lek ; 64(10): 695-7, 2007.
Artigo em Polonês | MEDLINE | ID: mdl-18409288

RESUMO

5-methylcytosine (m5C, 5mC) is a nucleotide occurring naturally in genomic DNA and play an important role in regulation of genes expression. Methylation of cytosine in DNA is an epigenetic modification and different intrinsic and extrinsic factors can influence on its level. For example, it is subject to modification and/or degradation by the free radicals which are commonly present in environment of human, among others the cigarette smoke. The reactions of m5C with free radicals lead to origination of many products which effect is decrease of level of m5C in DNA (hypomethylation) and excessive expression of genes inducing development of different diseases, especially cardiovascular system diseases. The aim of the study was statement if exist differences of level of 5-methylcytosine in DNA between smoking and non-smoking patients suffering from mild essential hypertension. The study group was composed of 30 patients suffering from mild essential hypertension (21 females and 40 males) aged from 18 to 55 years (32.4+/-10.3 years). The group of smoker was composed of 13 patients (5 females and 8 males) and the group of non-smokers was composed of 17 patients (7 females and 10 males). 3-5 ml of blood was sampled on EDTA and then thin-layer chromatography analysis of 5-methylcytosine level in DNA after previous enzymatic hydrolysis of DNA and radioactive phosphorus labeling [32p] was performed. The mean level of 5-methylcytosine (m5C) were 1.30+/-0.56 [%] in non-smoking patients, and 1.28+/-0.42 [%] in smoking patients suffering from mild essential hypertension. There is no significant statistically differences between non-smoking and smoking patients (p>0.4). In the study the following conclusion was drawn: the level of m5C in DNA of patients suffering from mild essential hypertension in the study is independent of smoking (p>0.4) in patients with mild essential hypertension. However it supposes, out of regard for theoretic datum suggestive such influence, the study should be performed in more frequent group of patients.


Assuntos
5-Metilcitosina/sangue , DNA/química , Hipertensão/sangue , Fumar/efeitos adversos , Fumar/sangue , Adolescente , Adulto , DNA/sangue , Epigênese Genética , Feminino , Expressão Gênica , Humanos , Masculino , Pessoa de Meia-Idade , Índice de Gravidade de Doença
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