RESUMO
BACKGROUND: The existence of differentiated thyroid cells is critical to respond radioactive iodide treatment strategy in thyroid cancer, and loss of the differentiated phenotype is a trademark of iodide-refractive thyroid disease. While high-dose therapy has been beneficial to several cancer patients, many studies have indicated this clinical benefit was limited to patients having BRAF mutation. BRAF-targeted paired box gene-8 (PAX8), a thyroid-specific transcription factor, generally dysregulated in BRAF-mutated thyroid cancer. METHODS: In this study, thyroid iodine-metabolizing gene levels were detected in BRAF-transformed thyroid cells after low and high dose of ionizing radiation. Also, an mRNA-targeted approach was used to figure out the underlying mechanism of low (0.01Gyx10 or 0.1Gy) and high (2Gy) radiation function on thyroid cancer cells after BRAFV600E mutation. RESULTS: Low dose radiation (LDR)-induced PAX8 upregulation restores not only BRAF-suppressive sodium/iodide symporter (NIS) expression, one of the major protein necessary for iodine uptake in healthy thyroid, on plasma membrane but also regulate other thyroid metabolizing genes levels. Importantly, LDR-induced PAX8 results in decreased cellular transformation in BRAF-mutated thyroid cells. CONCLUSION: The present findings provide evidence that LDR-induced PAX8 acts as an important regulator for suppression of thyroid carcinogenesis through novel STAT3/miR-330-5p pathway in thyroid cancers.
Assuntos
Transformação Celular Neoplásica/patologia , Transformação Celular Neoplásica/efeitos da radiação , Proteínas Proto-Oncogênicas B-raf/metabolismo , Glândula Tireoide/patologia , Glândula Tireoide/efeitos da radiação , Animais , Carcinogênese/patologia , Linhagem Celular Tumoral , Modelos Animais de Doenças , Relação Dose-Resposta à Radiação , Regulação Neoplásica da Expressão Gênica/efeitos da radiação , Humanos , Hipotireoidismo/patologia , Iodo/metabolismo , Camundongos Mutantes , MicroRNAs/genética , MicroRNAs/metabolismo , Modelos Biológicos , Mutação/genética , Fator de Transcrição PAX8/metabolismo , Proteínas Proto-Oncogênicas B-raf/genética , Fator de Transcrição STAT3/metabolismo , Neoplasias da Glândula Tireoide/genética , Neoplasias da Glândula Tireoide/patologia , Neoplasias da Glândula Tireoide/radioterapia , Regulação para Cima/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
BACKGROUND/AIMS: Radiation-induced skin fibrosis is a common side effect of clinical radiotherapy. Our previous next-generation sequencing (NGS) study demonstrated the reduced expression of the regulatory α subunit of phosphatidylinositol 3-kinase (PIK3r1) in irradiated murine skin. Metformin has been reported to target the PIK3-FOXO3 pathway. In this study, we investigated the effects of metformin on radiation-induced skin fibrosis. METHODS: Metformin was orally administered to irradiated mice. Skin fibrosis was analyzed by staining with H&E and Masson's trichrome stain. The levels of cytokines and chemokines associated with fibrosis were analyzed by immunohistochemistry and quantitative RT-PCR. The roles of PIK3rl and FOXO3 in radiation-induced skin fibrosis were studied by overexpressing PIK3rl and transfecting FOXO3 siRNA in NIH3T3 cells and mouse-derived dermal fibroblasts (MDF). RESULTS: The oral administration of metformin significantly reduced radiation-induced skin thickening and collagen accumulation and significantly reduced the radiation-induced expression of FOXO3 in murine skin. Additionally, the overexpression of PIK3r1 reduced the radiation-induced expression of FOXO3, while FOXO3 silencing decreased the radiation-induced expression of TGFß in vitro. CONCLUSIONS: The results indicated that metformin suppresses radiation-induced skin injuries by modulating the expression of FOXO3 through PIK3r1. Collectively, the data obtained in this study suggested that metformin could be a potent therapeutic agent for alleviating radiation-induced skin fibrosis.
Assuntos
Regulação para Baixo/efeitos dos fármacos , Proteína Forkhead Box O3/metabolismo , Metformina/farmacologia , Animais , Células Cultivadas , Classe Ia de Fosfatidilinositol 3-Quinase/genética , Classe Ia de Fosfatidilinositol 3-Quinase/metabolismo , Regulação para Baixo/efeitos da radiação , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Fibrose , Proteína Forkhead Box O3/antagonistas & inibidores , Proteína Forkhead Box O3/genética , Camundongos , Camundongos Endogâmicos C57BL , Células NIH 3T3 , Estresse Oxidativo/efeitos dos fármacos , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Lesões Experimentais por Radiação/patologia , Lesões Experimentais por Radiação/prevenção & controle , Radiação Ionizante , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo , Pele/efeitos dos fármacos , Pele/patologia , Pele/efeitos da radiação , Fator de Crescimento Transformador beta/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismoRESUMO
This study aimed to identify substances including Lactobacillus rhamnosus vitaP1 (KACC 92054P) that alleviate hangover-induced emotional anxiety and liver damage. The association between emotional anxiety caused by hangover and the genes P2X4, P2X7, SLC6A4 was investigated. In vitro and in vivo analyses were conducted to assess the influence of free-panica on alcohol-induced upregulated gene expression. Additionally, the concentration of AST, ALT, alcohol, and acetaldehyde in blood was measured. Free-panica, consisting of five natural products (Phyllanthus amarus, Phoenix dactylifera, Vitis vinifera, Zingiber officinale, and Lactobacillus rhamnosus), were evaluated for their regulatory effects on genes involved in alcohol-induced emotional anxiety and liver damage. The combination of these natural products in free-panica successfully restored emotional anxiety, and the concentration of AST, ALT, alcohol, and acetaldehyde in blood to those of the normal control group. These findings support the potential development of free-panica as a health functional food or medicinal intervention for relieving hangover symptoms and protecting liver from alcohol consumption.
RESUMO
Mast cells play important roles in many biological responses, such as those during allergic diseases and inflammatory disorders. Although laser and UV irradiation have immunosuppressive effects on inflammatory diseases by suppressing mast cells, little is known about the effects of γ-ionizing radiation on mast cells. In this study, we investigated the effects of γ-ionizing radiation on RBL-2H3 cells, a convenient model system for studying regulated secretion by mast cells. Low-dose radiation (<0.1 gray (Gy)) did not induce cell death, but high-dose radiation (>0.5 Gy) induced apoptosis. Low-dose ionizing radiation significantly suppressed the release of mediators (histamine, ß-hexosaminidase, IL-4, and tumor necrosis factor-α) from immunoglobulin E (IgE)-sensitized RBL-2H3 cells. To determine the mechanism of mediator release inhibition by ionizing radiation, we examined the activation of intracellular signaling molecules such as Lyn, Syk, phospholipase Cγ, PKCs, and MAPK, and intracellular free calcium concentrations ([Ca(2+)](i)). The phosphorylation of signaling molecules following stimulation of high-affinity IgE receptor I (FcεRI) was specifically inhibited by low-dose ionizing radiation (0.01 Gy). These results were due to the suppression of FcεRI expression by the low-dose ionizing radiation. Therefore, low-dose ionizing radiation (0.01 Gy) may function as a novel inhibitor of mast cell activation.
Assuntos
Raios gama , Leucemia Basofílica Aguda/metabolismo , Mastócitos/metabolismo , Proteínas de Neoplasias/metabolismo , Transdução de Sinais/efeitos da radiação , Animais , Apoptose/efeitos da radiação , Linhagem Celular Tumoral , Relação Dose-Resposta à Radiação , Leucemia Basofílica Aguda/patologia , Mastócitos/patologia , Fosforilação/efeitos da radiação , RatosRESUMO
H2AX plays an important role in chromatin reorganization implicated in DNA repair and apoptosis under various DNA damaging conditions. In this study, the interaction between TOPORS (topoisomerase I-binding protein) and H2AX was verified using mammalian cell extracts exposed to diverse DNA damaging stresses such as ionizing radiation, doxorubicin, camptothecin, and hydrogen peroxide. In vitro assays for ubiquitination revealed that TOPORS functions as a novel E3 ligase for H2AX ubiquitination. TOPORS was found to be dissociated from H2AX proteins when cells were exposed to oxidative stress, but not replication-inducing DNA damaging stress. The protein stability of H2AX was decreased when TOPORS was ectopically expressed in cells, and oxidative stresses such as hydrogen peroxide and ionizing radiation induced recovery of the H2AX protein level. Therefore, these biochemical data suggest that TOPORS plays a key role in the turnover of H2AX protein, discriminating the type of DNA damaging stress.
Assuntos
Cromatina , Quebras de DNA de Cadeia Dupla , Histonas/metabolismo , Proteínas de Neoplasias/metabolismo , Proteínas Nucleares/metabolismo , Estresse Oxidativo , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação , Antineoplásicos/farmacologia , Camptotecina/farmacologia , Linhagem Celular , Cromatina/efeitos dos fármacos , Cromatina/efeitos da radiação , Quebras de DNA de Cadeia Dupla/efeitos dos fármacos , Quebras de DNA de Cadeia Dupla/efeitos da radiação , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Doxorrubicina/farmacologia , Raios gama/efeitos adversos , Células HEK293 , Histonas/genética , Humanos , Peróxido de Hidrogênio/farmacologia , Proteínas de Neoplasias/genética , Proteínas Nucleares/genética , Oxidantes/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/efeitos da radiação , Estabilidade Proteica/efeitos dos fármacos , Estabilidade Proteica/efeitos da radiação , Proteínas Recombinantes de Fusão/metabolismo , Sumoilação/efeitos dos fármacos , Sumoilação/efeitos da radiação , Ubiquitina-Proteína Ligases/genética , Ubiquitinação/efeitos dos fármacos , Ubiquitinação/efeitos da radiaçãoRESUMO
AKT phosphorylates components of the intrinsic cell survival machinery and promotes survival to various stimuli. In the present study, we identified CDC-like kinase 2 (CLK2) as a new substrate of AKT activation and elucidated its role in cell survival to ionizing radiation. AKT directly binds to and phosphorylates CLK2 on serine 34 and threonine 127, in vitro and in vivo. CLK2 phosphorylation was detected in HeLa cells overexpressing active AKT. In addition, we demonstrated that ionizing radiation induces CLK2 phosphorylation via AKT activation. In contrast, the suppression of endogenous AKT expression by siRNA inhibited CLK2 phosphorylation in response to 2 gray of γ-ray or insulin. Furthermore, we examined the effect of CLK2 on the survival of irradiated CCD-18Lu cells overexpressing Myc-CLK2. CLK2 overexpression significantly increased cell growth and inhibited cell death induced by 2 gray. The role of CLK2 in cell survival to ionizing radiation was dependent on the phosphorylation of serine 34 and threonine 127. Our results suggest that AKT activation controls cell survival to ionizing radiation by phosphorylating CLK2, revealing an important regulatory mechanism required for promoting cell survival.
Assuntos
Raios gama/efeitos adversos , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Tirosina Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Morte Celular/efeitos dos fármacos , Morte Celular/genética , Morte Celular/efeitos da radiação , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Sobrevivência Celular/efeitos da radiação , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/genética , Ativação Enzimática/efeitos da radiação , Inativação Gênica , Células HeLa , Humanos , Hipoglicemiantes/farmacologia , Insulina/farmacologia , Fosforilação/efeitos dos fármacos , Fosforilação/genética , Fosforilação/efeitos da radiação , Proteínas Serina-Treonina Quinases/genética , Proteínas Tirosina Quinases/genética , Proteínas Proto-Oncogênicas c-akt/genética , RNA Interferente PequenoRESUMO
Ionizing radiation generates oxidative stress, which is thought to be a major cause of aging. Although living organisms are constantly exposed to low levels of radiation, most studies examining the effect of radiation have focused on accelerated aging and diminished life span that result from high-dose radiation. On the other hand, several studies have suggested that low-dose radiation enhances the longevity of Drosophila melanogaster. Therefore, investigation of the biological effects of low-dose radiation could contribute to a more comprehensive understanding of the aging process. In this study, microarray and quantitative real time-PCR were used to measure genome-wide changes in transcript levels in low-dose irradiated fruit flies that showed enhanced longevity. In response to radiation, approximately 13% of the genome exhibited changes in gene expression, and a number of aging-related genes were significantly regulated. These data were compared with quantitative trait loci affecting life-span to identify candidate genes involved in enhanced longevity induced by low-dose radiation. This genome-wide survey revealed novel information about changes in transcript levels in low-dose irradiated flies and identified 39 new candidate genes for molecular markers of extended longevity induced by ionizing radiation. In addition, this study also suggests a mechanism by which low-dose radiation extends longevity.
Assuntos
Drosophila melanogaster/genética , Drosophila melanogaster/fisiologia , Drosophila melanogaster/efeitos da radiação , Expressão Gênica/efeitos da radiação , Genoma/efeitos da radiação , Longevidade/genética , Animais , Perfilação da Expressão Gênica , Longevidade/efeitos da radiação , Masculino , Análise em Microsséries , Estresse Oxidativo/genética , Estresse Oxidativo/efeitos da radiação , Reação em Cadeia da Polimerase/métodos , Locos de Características Quantitativas , Radiação IonizanteRESUMO
While a high-dose of ionizing radiation is generally harmful and causes damage to living organisms, a low-dose of radiation has been shown to be beneficial in a variety of animal models. To understand the basis for the effect of low-dose radiation in vivo, we examined the cellular and immunological changes evoked in mice exposed to low-dose radiation at very low (0.7mGy/h) and low (3.95mGy/h) dose rate for the total dose of 0.2 and 2Gy, respectively. Mice exposed to low-dose radiation, either at very low- or low-dose rate, demonstrated normal range of body weight and complete blood counts. Likewise, the number and percentage of peripheral lymphocyte populations, CD4(+) T, CD8(+) T, B, or NK cells, stayed unchanged following irradiation. Nonetheless, the sera from these mice exhibited elevated levels of IL-3, IL-4, leptin, MCP-1, MCP-5, MIP-1alpha, thrombopoietin, and VEGF along with slight reduction of IL-12p70, IL-13, IL-17, and IFN-gamma. This pattern of cytokine release suggests the stimulation of innate immunity facilitating myeloid differentiation and activation while suppressing pro-inflammatory responses and promoting differentiation of naïve T cells into T-helper 2, not T-helper 1, types. Collectively, our data highlight the subtle changes of cytokine milieu by chronic low-dose gamma-radiation, which may be associated with the functional benefits observed in various experimental models.
Assuntos
Citocinas/metabolismo , Raios gama , Imunidade/efeitos da radiação , Animais , Células Sanguíneas/imunologia , Células Sanguíneas/efeitos da radiação , Peso Corporal/efeitos da radiação , Relação Dose-Resposta à Radiação , Feminino , Linfócitos/imunologia , Linfócitos/efeitos da radiação , Camundongos , Camundongos Endogâmicos C57BLRESUMO
We apologize that there are some errors in the references for three sentences and Table 2.
RESUMO
MicroRNAs (miRNAs) are short single-stranded RNA molecules that regulate the stability or translational efficiency of target messenger RNAs. Specific miRNAs are required for strict tissue- and developmental stage-specific expression. These miRNAs have roles in many human tumor malignancies and their expression is specifically regulated on each stage of oncogenic process. Therefore, miRNA expression profiling can be used as a new class of biomarker that indicates the development of cancer. Many recent studies indicated that cell exposure to ionizing radiation also induces various physiological responses including DNA repair, cell cycle arrest, cell death and differentiation. In addition, some studies suggest that exposure to low dose radiation induces a favorable effect on cells. However, the functions of miRNAs related to the response of irradiated cells have not been well studied, especially after low dose radiation. In this study, expression profiles of miRNAs isolated from irradiated cells at low and high dose radiation were analyzed with microarrays, and these data were validated using quantitative RT-PCR. Here, we describe specific miRNAs that are expressed in a dose-dependent manner that serve as new markers of irradiated immune cells.
Assuntos
Linfócitos B/efeitos da radiação , Raios gama/efeitos adversos , Expressão Gênica/efeitos da radiação , MicroRNAs/efeitos da radiação , Western Blotting , Relação Dose-Resposta à Radiação , Perfilação da Expressão Gênica , Humanos , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
We apologize that there are some errors in the references for three sentences and Table 2.
RESUMO
We focused on the transcriptional responses induced by low and very low doses of ionizing radiation with time effect. Regardless of their importance only a few limited studies have been done. Here we applied a large-scale gene transcript profile to elucidate the genes and biological pathways. Immortalized human mesenchymal stem cells were irradiated with 0.01, 0.05, 0.2 and 1 Gy of gamma radiation and total RNA was extracted from each cell line at 1, 4, 12 and 48 h after exposure. The essential transcriptional responses were identified according to dose and time. A total of 6,016 genes showed altered expression patterns at more than one time point or dose level among the investigated 10,800 genes. Genes that showed dose-dependent expression responses were involved in signal transduction, regulation of transcription, proteolysis, peptidolysis and metabolism. Those that showed time-dependent responses were divided into two distinct groups: the up-and-down group was associated with 'cellular defense mechanisms' such as apoptosis, cell adhesion, stress response and immune response and the down-and-up group with 'fundamental cellular processes' such as DNA replication, mitosis, RNA splicing, DNA repair and translation initiation. Genes showing both dose-and time-dependent responses exhibited a mixture of both features. A highly non-linear relationship between the IR dose and the transcriptional relative response was obtained from the dose-dependent group. The time-dependent group also exhibited a non-linear relationship as the complex effect group did. Some of the early-reactive-phase (1-4 h) genes showed a differential expression response to 0.01, 0.05 and 0.2 Gy but were unresponsive to 1 Gy. Some of the late-recovery-phase (12-48 h) genes showed a differential expression to 1 Gy but were relatively unresponsive to other doses. We further characterized the gene expression patterns that could be implicated in the molecular mechanism of the cellular responses to low and very low-dose irradiation.
Assuntos
Expressão Gênica/efeitos da radiação , Células-Tronco Mesenquimais/efeitos da radiação , Transcrição Gênica/efeitos da radiação , Linhagem Celular , Relação Dose-Resposta à Radiação , Perfilação da Expressão Gênica , Humanos , Hibridização In Situ , Análise de Sequência com Séries de Oligonucleotídeos , Radiação Ionizante , TempoRESUMO
Apoptosis executed by the mammalian caspase family plays a fundamental role in cellular homeostasis. Deregulation of this process is associated with several human diseases. The multimerization of ligand-induced death receptors results in the recruitment of the death inducing signaling complex and autocatalytic activation of initiator caspases, including caspase-8 and -10. However, it is still unclear how initiator caspases trigger and control the early apoptotic signaling pathways, partly because the downstream proteolytic cleavage targets of the initiator caspases are not completely known. Although it is known that a number of proteins are cleaved by various members of the caspase family, the identification of specific cleavage substrates of the initiator caspases 8 and 10, has been hindered by a lack of systematic and broadly applicable strategies for substrate identification. In the present study we constructed a mouse cDNA library and used it to perform a systematic, genome-wide screen for novel in vitro substrates of caspase-8 and -10. From this, we successfully identified six putative caspase substrates, including five novel proteins (ABCF1, AKAP1, CPE, DOPEY1 and GOPC1) that may be targeted specifically by the initiator caspases 8 and 10 during the early stages of apoptosis. These findings may provide useful information for elucidating the apoptotic signaling pathways downstream of the death receptors.
Assuntos
Caspase 10/metabolismo , Caspase 8/metabolismo , Genoma/genética , Processamento de Proteína Pós-Traducional , Animais , Células Clonais , Biologia Computacional , DNA Complementar/isolamento & purificação , Biblioteca Gênica , Fígado/enzimologia , Camundongos , Reprodutibilidade dos Testes , Especificidade por SubstratoRESUMO
Radiotherapy is one of the most efficient ways to treat cancer. However, deleterious effects, such as acute and chronic toxicities that reduce the quality of life, may result. Naturally occurring compounds have been shown to be non-toxic over wide dose ranges and are inexpensive and effective. Additionally, pharmacological strategies have been developed that use radioprotectors to inhibit radiation-induced toxicities. Currently available radioprotectors have several limitations, including toxicity. In this review, we present the mechanisms of proven radioprotectors, ranging from free radical scavenging (the best-known mechanism of radioprotection) to molecular-based radioprotection (e.g., upregulating expression of heat shock proteins). Finally, we discuss naturally occurring compounds with radioprotective properties in the context of these mechanisms.
Assuntos
Produtos Biológicos/farmacologia , Lesões por Radiação/prevenção & controle , Protetores contra Radiação/farmacologia , Radioterapia/efeitos adversos , Animais , Apoptose/efeitos dos fármacos , Produtos Biológicos/isolamento & purificação , Reparo do DNA , Radicais Livres/metabolismo , Humanos , Neoplasias/terapia , Qualidade de Vida , Lesões por Radiação/genética , Lesões por Radiação/imunologia , Lesões por Radiação/patologia , Protetores contra Radiação/isolamento & purificaçãoRESUMO
The biological effects of low-dose radiation have been investigated and debated for more than a century, but its cellular effects and regulatory mechanisms remain poorly understood. This study shows the human cellular responses to low-dose radiation in CCD-18 Lu cells, which are derived from normal human lung fibroblasts. We examined a colony-forming assay for cell survival by ionizing radiation. Live cell counting and cell cycle analysis were measured for cell proliferation and cell cycle progression following low-dose irradiation. We examined Raf and Akt phosphorylation to determine the proliferation mechanism resulting from low-dose radiation. We also observed that p53 and p21 were related to cell cycle response. We found that 0.05 Gy of ionizing radiation enhanced cell proliferation and did not change the progression of the cell cycle. In addition, 0.05 Gy of ionizing radiation transiently activated Raf and Akt, but did not change phospho-p53, p53 and p21 in CCD-18 Lu cells. However, 2 Gy of ionizing radiation induced cell cycle arrest, phosphorylation of p53, and expression of p53 and p21. The phosphorylation of Raf and Akt proteins induced by 0.05 Gy of ionizing radiation was abolished by pre-treatment with an EGFR inhibitor, AG1478, or a PI3k inhibitor, LY294002. Cell proliferation stimulated by 0.05 Gy of ionizing radiation was blocked by the suppression of Raf and Akt phosphorylation with these inhibitors. These results suggest that 0.05 Gy of ionizing radiation stimulates cell proliferation through the transient activation of Raf and Akt in CCD-18 Lu cells.
Assuntos
Fibroblastos/efeitos da radiação , Proteínas Proto-Oncogênicas c-akt/efeitos da radiação , Proteínas Proto-Oncogênicas c-raf/efeitos da radiação , Proliferação de Células/efeitos da radiação , Cromonas/farmacologia , Ativação Enzimática , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Raios gama , Humanos , Pulmão/citologia , Morfolinas/farmacologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas c-raf/metabolismo , Quinazolinas , Transdução de Sinais/efeitos da radiação , Proteína Supressora de Tumor p53/biossíntese , Proteína Supressora de Tumor p53/metabolismo , Tirfostinas/farmacologia , Quinases Ativadas por p21/biossínteseRESUMO
This study shows the human cellular responses and the mechanism of low-dose ionizing radiation in CCD 18 Lu cells, which are derived from normal human lung fibroblasts. Cell proliferation and viability assay were measured for the cells following gamma-irradiation using trypan blue, BrdU incorporation, and Wst-1 assay. We also examined genotoxicity using a micronuclei formation assay. The activation of the MAPKs pathway was determined by Western blot analysis, and the siRNA system was used to inhibit the expression of ERK1/2 and p38. We found that 0.05 Gy of ionizing radiation stimulated cell proliferation and did not change Micronuclei frequencies. In addition, 0.05 Gy of ionizing radiation activated ERK1/2 and p38, but did not activate JNK1/2 in cells. A specific ERK1/2 inhibitor, U0126, decreased the phosphorylation of ERK1/2 proteins induced by 0.05 Gy of ionizing radiation, and a similar suppressive effect was observed with a p38 inhibitor, PD169316. Suppression of ERK1/2 and p38 phosphorylation with these inhibitors decreased cell proliferation, which was stimulated by 0.05 Gy of ionizing radiation. Furthermore, downregulation of ERK1/2 and p38 expression using siRNA blocked the cell proliferation that had been increased by 0.05 Gy of ionizing radiation. These results suggest that 0.05 Gy of ionizing radiation enhances cell proliferation through the activation of ERK1/2 and p38 in normal human lung fibroblasts.
Assuntos
Fibroblastos/fisiologia , Fibroblastos/efeitos da radiação , Pulmão/metabolismo , Pulmão/efeitos da radiação , Sistema de Sinalização das MAP Quinases/fisiologia , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Linhagem Celular , Proliferação de Células/efeitos da radiação , Relação Dose-Resposta à Radiação , Ativação Enzimática/efeitos da radiação , Humanos , Pulmão/citologia , Sistema de Sinalização das MAP Quinases/efeitos da radiação , Doses de RadiaçãoRESUMO
PURPOSE: Low-dose radiation has various biological effects such as adaptive responses, low-dose hypersensitivity, as well as beneficial effects. However, little is known about the particular proteins involved in these effects. Here, we sought to identify low-dose radiation-responsive phosphoproteins in normal fibroblast cells. MATERIALS AND METHODS: We assessed genomic instability and proliferation of fibroblast cells after γ-irradiation by γ-H2AX foci and micronucleus formation analyses and BrdU incorporation assay, respectively. We screened fibroblast cells 8 h after low-dose (0.05 Gy) γ-irradiation using Phospho Explorer Antibody Microarray and validated two differentially expressed phosphoproteins using Western blotting. RESULTS: Cell proliferation proceeded normally in the absence of genomic instability after low-dose γ-irradiation. Phospho antibody microarray analysis and Western blotting revealed increased expression of two phosphoproteins, phospho-NFκB (Ser536) and phospho-P70S6K (Ser418), 8 h after low-dose radiation. CONCLUSIONS: Our findings suggest that low-dose radiation of normal fibroblast cells activates the expression of phospho-NFκB (Ser536) and phospho-P70S6K (Ser418) in the absence of genomic instability. Therefore, these proteins may be involved in DNA damage repair processes.
Assuntos
Fibroblastos/metabolismo , Fibroblastos/efeitos da radiação , Instabilidade Genômica/efeitos da radiação , Fosfoproteínas/metabolismo , Proliferação de Células/efeitos da radiação , Dano ao DNA , Reparo do DNA/efeitos da radiação , Relação Dose-Resposta à Radiação , Fibroblastos/citologia , Raios gama/efeitos adversos , Regulação da Expressão Gênica/efeitos da radiação , Humanos , NF-kappa B/metabolismo , Tolerância a Radiação/genética , Proteínas Quinases S6 Ribossômicas 70-kDa/metabolismo , Fatores de TempoRESUMO
Ionizing radiation causes biological damage that leads to severe health effects. However, the effects and subsequent health implications caused by exposure to low-dose radiation are unclear. The objective of this study was to determine phosphoprotein profiles in normal human fibroblast cell lines in response to low-dose and high-dose γ-radiation. We examined the cellular response in MRC-5 cells 0.5 h after exposure to 0.05 or 2 Gy. Using 1318 antibodies by antibody array, we observed ≥1.3-fold increases in a number of identified phosphoproteins in cells subjected to low-dose (0.05 Gy) and high-dose (2 Gy) radiation, suggesting that both radiation levels stimulate distinct signaling pathways. Low-dose radiation induced nucleic acid-binding transcription factor activity, developmental processes, and multicellular organismal processes. By contrast, high-dose radiation stimulated apoptotic processes, cell adhesion and regulation, and cellular organization and biogenesis. We found that phospho-BTK (Tyr550) and phospho-Gab2 (Tyr643) protein levels at 0.5 h after treatment were higher in cells subjected to low-dose radiation than in cells treated with high-dose radiation. We also determined that the phosphorylation of BTK and Gab2 in response to ionizing radiation was regulated in a dose-dependent manner in MRC-5 and NHDF cells. Our study provides new insights into the biological responses to low-dose γ-radiation and identifies potential candidate markers for monitoring exposure to low-dose ionizing radiation.
Assuntos
Biomarcadores/metabolismo , Fibroblastos/citologia , Fibroblastos/efeitos da radiação , Raios gama , Fosfoproteínas/metabolismo , Proteômica , Western Blotting , Linhagem Celular , Dano ao DNA , Relação Dose-Resposta à Radiação , Fibroblastos/metabolismo , Humanos , Análise Serial de Proteínas , Reprodutibilidade dos TestesRESUMO
In the present study, we investigated the effect of tyndallized HY7712 (tHY7712) on the expression of Th cell specific transcription factors and cytokines in whole-body γ-irradiated mice. Oral administration of tHY7712 strongly recovered the γ-irradiation-suppressed expression of helper T (Th) cell- and regulatory T cell-related transcription factors and cytokines, such as T-bet, Foxp3, IFN-γ, TNF-α, and IL-10, and suppressed Th2 cell-associated transcription factor and cytokine GATA3 and IL-5, respectively. Furthermore, compared with the control, tHY7712 treatment also restored γ-irradiation-impaired natural killer and cytotoxic T cell activities against YAC-1 tumor cells to 97.8% and 98.6%, respectively.
Assuntos
Diferenciação Celular/efeitos da radiação , Raios gama/efeitos adversos , Lactobacillus plantarum/fisiologia , Linfócitos T Auxiliares-Indutores/efeitos da radiação , Irradiação Corporal Total , Animais , Citocinas/metabolismo , Camundongos , Probióticos/administração & dosagem , Linfócitos T Auxiliares-Indutores/citologia , Linfócitos T Reguladores/citologia , Linfócitos T Reguladores/efeitos da radiação , Fatores de Transcrição/metabolismoRESUMO
Three in vitro dose calibration curves for biodosimetry such as dicentric chromosome assay, fluorescence in situ hybridization (FISH) assay for translocation, and micronuclei (MNs) in binucleated cell assay were established after exposure to ionizing radiation. Peripheral blood lymphocyte samples obtained from healthy donors were irradiated with 60Co source at a dose rate of 0.5 Gy/min to doses of 0.1-6 Gy. The results from three in vitro dose calibration curves for biodosimetry were analyzed to understand the relationship among biodosimetry assay techniques. Our comparison demonstrates that there is a very strong positive correlation among the dicentric assay, FISH, and MNs analysis, and these three biodosimetry assays strongly support the in vitro dose reconstruction and the emergency preparedness of public or occupational radiation overexposure.