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1.
Int J Radiat Biol ; 100(11): 1527-1540, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39288264

RESUMO

PURPOSE: Exposure to low doses (LD) of ionizing radiation (IR), such as the ones employed in computed tomography (CT) examination, can be associated with cancer risk. However, cancer development could depend on individual radiosensitivity. In the present study, we evaluated the differences in the response to a CT-scan radiation dose of 20 mGy in two lymphoblastoid cell lines with different radiosensitivity. MATERIALS AND METHODS: Several parameters were studied: gene expression, DNA damage, and its repair, as well as cell viability, proliferation, and death. Results were compared with those after a medium dose of 500 mGy. RESULTS: After 20 mGy of IR, the radiosensitive (RS) cell line showed an increase in DNA damage, and higher cell proliferation and apoptosis, whereas the radioresistant (RR) cell line was insensitive to this LD. Interestingly, the RR cell line showed a higher expression of an antioxidant gene, which could be used by the cells as a protective mechanism. After a dose of 500 mGy, both cell lines were affected by IR but with significant differences. The RS cells presented an increase in DNA damage and apoptosis, but a decrease in cell proliferation and cell viability, as well as less antioxidant response. CONCLUSIONS: A differential biological effect was observed between two cell lines with different radiosensitivity, and these differences are especially interesting after a CT scan dose. If this is confirmed by further studies, one could think that individuals with radiosensitivity-related genetic variants may be more vulnerable to long-term effects of IR, potentially increasing cancer risk after LD exposure.


Assuntos
Apoptose , Proliferação de Células , Sobrevivência Celular , Dano ao DNA , Relação Dose-Resposta à Radiação , Tolerância a Radiação , Humanos , Sobrevivência Celular/efeitos da radiação , Apoptose/efeitos da radiação , Proliferação de Células/efeitos da radiação , Linhagem Celular , Radiação Ionizante , Doses de Radiação
3.
Thyroid ; 33(9): 1100-1109, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37300484

RESUMO

Background: Understanding of changes in salivary and lacrimal gland functions after radioactive iodine therapy (131I-therapy) remains limited, and, to date, no studies have evaluated dose-response relationships between absorbed dose from 131I-therapy and dysfunctions of these glands. This study investigates salivary/lacrimal dysfunctions in differentiated thyroid cancer (DTC) patients six months after 131I-therapy, identifies 131I-therapy-related risk factors for salivary/lacrimal dysfunctions, and assesses the relationships between 131I-therapy radiation dose and these dysfunctions. Methods: A cohort study was conducted involving 136 DTC patients treated by 131I-therapy of whom 44 and 92 patients received 1.1 and 3.7 GBq, respectively. Absorbed dose to the salivary glands was estimated using a dosimetric reconstruction method based on thermoluminescent dosimeter measurements. Salivary and lacrimal functions were assessed at baseline (T0, i.e., immediately before 131I-therapy) and six months later (T6) using validated questionnaires and salivary samplings, with and without stimulation of the salivary glands. Statistical analyses included descriptive analyses and random-effects multivariate logistic and linear regressions. Results: There was no difference between T0 and T6 in the level of parotid gland pain, nor was there difference in the number of patients with hyposalivation, but there were significantly more patients with dry mouth sensation and dry eyes after therapy compared with baseline. Age, menopause, depression and anxiety symptoms, history of systemic disease, and not taking painkillers in the past three months were found to be significantly associated with salivary or lacrimal disorders. Significant associations were found between 131I-exposure and salivary disorders adjusted on the previous variables: for example, per 1-Gy increase in mean dose to the salivary glands, odds ratio = 1.43 [CI 1.02 to 2.04] for dry mouth sensation, ß = -0.08 [CI -0.12 to -0.02] mL/min for stimulated saliva flow, and ß = 1.07 [CI 0.42 to 1.71] mmol/L for salivary potassium concentration. Conclusions: This study brings new knowledge on the relationship between the absorbed dose to the salivary glands from 131I-therapy and salivary/lacrimal dysfunctions in DTC patients six months after 131I-therapy. Despite the findings of some dysfunctions, the results do not show any obvious clinical disorders after the 131I-therapy. Nevertheless, this study raises awareness of the risk factors for salivary disorders, and calls for longer follow-up. Clinical Trials Registration: Number NCT04876287 on the public website (ClinicalTrials.gov).


Assuntos
Aparelho Lacrimal , Doenças das Glândulas Salivares , Neoplasias da Glândula Tireoide , Xerostomia , Feminino , Humanos , Estudos de Coortes , Seguimentos , Radioisótopos do Iodo/efeitos adversos , Aparelho Lacrimal/efeitos da radiação , Neoplasias da Glândula Tireoide/tratamento farmacológico , Xerostomia/induzido quimicamente , Xerostomia/diagnóstico
4.
Biology (Basel) ; 11(8)2022 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-36009820

RESUMO

Radiation therapy is widely used as an anti-neoplastic treatment despite the adverse effects it can cause in non-tumoral tissues. Radiosensitizing agents, which can increase the effect of radiation in tumor cells, such as gold nanoparticles (GNPs), have been described. To evaluate the radiosensitizing effect of 50 nm GNPs, we carried out a series of studies in two neoplastic cell lines, Caco2 (colon adenocarcinoma) and SKBR3 (breast adenocarcinoma), qualitatively evaluating the internalization of the particles, determining with immunofluorescence the number of γ-H2AX foci after irradiation with ionizing radiation (3 Gy) and evaluating the viability rate of both cell lines after treatment by means of an MTT assay. Nanoparticle internalization varied between cell lines, though they both showed higher internalization degrees for functionalized GNPs. The γ-H2AX foci counts for the different times analyzed showed remarkable differences between cell lines, although they were always significantly higher for functionalized GNPs in both lines. Regarding cell viability, in most cases a statistically significant decreasing tendency was observed when treated with GNPs, especially those that were functionalized. Our results led us to conclude that, while 50 nm GNPs induce a clear radiosensitizing effect, it is highly difficult to describe the magnitude of this effect as universal because of the heterogeneity found between cell lines.

5.
Biomolecules ; 12(8)2022 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-35892331

RESUMO

Molecular cancer biomarkers are any measurable molecular indicator of risk of cancer, occurrence of cancer, or patient outcome. They may include germline or somatic genetic variants, epigenetic signatures, transcriptional changes, and proteomic signatures. These indicators are based on biomolecules, such as nucleic acids and proteins, that can be detected in samples obtained from tissues through tumor biopsy or, more easily and non-invasively, from blood (or serum or plasma), saliva, buccal swabs, stool, urine, etc. Detection technologies have advanced tremendously over the last decades, including techniques such as next-generation sequencing, nanotechnology, or methods to study circulating tumor DNA/RNA or exosomes. Clinical applications of biomarkers are extensive. They can be used as tools for cancer risk assessment, screening and early detection of cancer, accurate diagnosis, patient prognosis, prediction of response to therapy, and cancer surveillance and monitoring response. Therefore, they can help to optimize making decisions in clinical practice. Moreover, precision oncology is needed for newly developed targeted therapies, as they are functional only in patients with specific cancer genetic mutations, and biomarkers are the tools used for the identification of these subsets of patients. Improvement in the field of cancer biomarkers is, however, needed to overcome the scientific challenge of developing new biomarkers with greater sensitivity, specificity, and positive predictive value.


Assuntos
Neoplasias , Biomarcadores Tumorais/metabolismo , Humanos , Oncologia , Neoplasias/diagnóstico , Neoplasias/genética , Medicina de Precisão/métodos , Proteômica
6.
JMIR Res Protoc ; 11(7): e35565, 2022 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-35867385

RESUMO

BACKGROUND: Following radioiodine (131I) therapy of differentiated thyroid cancer, the salivary glands may become inflamed, leading to dysfunctions and decreases in patients' nutritional status and quality of life. The incidence of these dysfunctions after 131I-therapy is poorly known, and no clinical or genetic factors have been identified to date to define at-risk patients, which would allow the delivered activity to be adapted to the expected risk of salivary dysfunctions. OBJECTIVE: The aims of this study are to estimate the incidence of salivary dysfunctions, and consequences on the quality of life and nutritional status for patients after 131I-therapy; to characterize at-risk patients of developing posttreatment dysfunctions using clinical, biomolecular, and biochemical factors; and to validate a dosimetric method to calculate the dose received at the salivary gland level for analyzing the dose-response relationship between absorbed doses to salivary glands and salivary dysfunctions. METHODS: This prospective study aims to include patients for whom 131I-therapy is indicated as part of the treatment for differentiated thyroid cancer in a Paris hospital (40 and 80 patients in the 1.1 GBq and 3.7 GBq groups, respectively). The follow-up is based on three scheduled visits: at inclusion (T0, immediately before 131I-therapy), and at 6 months (T6) and 18 months (T18) posttreatment. For each visit, questionnaires on salivary dysfunctions (validated French tool), quality of life (Hospital Anxiety and Depression scale, Medical Outcomes Study 36-Item Short Form Survey), and nutritional status (visual analog scale) are administered by a trained clinical research associate. At T0 and T6, saliva samples and individual measurements of the salivary flow, without and with salivary glands stimulation, are performed. External thermoluminescent dosimeters are positioned on the skin opposite the salivary glands and at the sternal fork immediately before 131I administration and removed after 5 days. From the doses recorded by the dosimeters, an estimation of the dose received at the salivary glands will be carried out using physical and computational phantoms. Genetic and epigenetic analyses will be performed to search for potential biomarkers of the predisposition to develop salivary dysfunctions after 131I-therapy. RESULTS: A total of 139 patients (99 women, 71.2%; mean age 47.4, SD 14.3 years) were enrolled in the study between September 2020 and April 2021 (45 and 94 patients in the 1.1 GBq and 3.7G Bq groups, respectively). T6 follow-up is complete and T18 follow-up is currently underway. Statistical analyses will assess the links between salivary dysfunctions and absorbed doses to the salivary glands, accounting for associated factors. Moreover, impacts on the patients' quality of life will be analyzed. CONCLUSIONS: To our knowledge, this study is the first to investigate the risk of salivary dysfunctions (using both objective and subjective indicators) in relation to organ (salivary glands) doses, based on individual dosimeter records and dose reconstructions. The results will allow the identification of patients at risk of salivary dysfunctions and will permit clinicians to propose a more adapted follow-up and/or countermeasures to adverse effects. TRIAL REGISTRATION: ClinicalTrials.gov NCT04876287; https://clinicaltrials.gov/ct2/show/NCT04876287. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/35565.

7.
Environ Int ; 149: 106212, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33293042

RESUMO

Ionizing radiation interacts with the immune system in many ways with a multiplicity that mirrors the complexity of the immune system itself: namely the need to maintain a delicate balance between different compartments, cells and soluble factors that work collectively to protect, maintain, and restore tissue function in the face of severe challenges including radiation damage. The cytotoxic effects of high dose radiation are less relevant after low dose exposure, where subtle quantitative and functional effects predominate that may go unnoticed until late after exposure or after a second challenge reveals or exacerbates the effects. For example, low doses may permanently alter immune fitness and therefore accelerate immune senescence and pave the way for a wide spectrum of possible pathophysiological events, including early-onset of age-related degenerative disorders and cancer. By contrast, the so called low dose radiation therapy displays beneficial, anti-inflammatory and pain relieving properties in chronic inflammatory and degenerative diseases. In this review, epidemiological, clinical and experimental data regarding the effects of low-dose radiation on the homeostasis and functional integrity of immune cells will be discussed, as will be the role of immune-mediated mechanisms in the systemic manifestation of localized exposures such as inflammatory reactions. The central conclusion is that ionizing radiation fundamentally and durably reshapes the immune system. Further, the importance of discovery of immunological pathways for modifying radiation resilience amongst other research directions in this field is implied.


Assuntos
Neoplasias , Radiação Ionizante , Relação Dose-Resposta à Radiação , Humanos , Sistema Imunitário , Inflamação
8.
Sci Rep ; 9(1): 150, 2019 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-30655613

RESUMO

One of the most severe complications after successful cancer therapy is the development of therapy-related myeloid neoplasms (t-MN). Constitutional genetic variation is likely to impact on t-MN risk. We aimed to evaluate if polymorphisms in the p53 pathway can be useful for predicting t-MN susceptibility. First, an association study revealed that the Pro variant of the TP53 Arg72Pro polymorphism and the G allele of the MDM2 SNP309 were associated with t-MN risk. The Arg variant of TP53 is more efficient at inducing apoptosis, whereas the Pro variant is a more potent inductor of cell cycle arrest and DNA repair. As regards MDM2 SNP309, the G allele is associated with attenuation of the p53 apoptotic response. Second, to evaluate the biological effect of the TP53 polymorphism, we established Jurkat isogenic cell lines expressing p53Arg or p53Pro. Jurkat p53Arg cells presented higher DNA damage and higher apoptotic potential than p53Pro cells, after treatment with chemotherapy agents. Only p53Pro cells presented t(15;17) translocation and del(5q). We suggest that failure to repair DNA lesions in p53Arg cells would lead them to apoptosis, whereas some p53Pro cells, prone to cell cycle arrest and DNA repair, could undergo misrepair, generating chromosomal abnormalities typical of t-MN.


Assuntos
Leucemia/tratamento farmacológico , Segunda Neoplasia Primária/genética , Proteínas Proto-Oncogênicas c-mdm2/genética , Proteína Supressora de Tumor p53/genética , Feminino , Predisposição Genética para Doença , Humanos , Células Jurkat , Masculino , Polimorfismo de Nucleotídeo Único , Fatores de Risco
10.
Genes Chromosomes Cancer ; 55(12): 905-914, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27480453

RESUMO

Lung carcinoma is one of the most common causes of cancer-related mortality worldwide. It is an aggressive tumor, often diagnosed at an advanced stage when treatment options are limited. Currently, the importance of detection and assessment of various genetic alterations in cancer is recognized as they can serve as very helpful markers in early diagnosis and follow-up of treatment regimens. Recently, several therapeutically important genetic markers have been identified. One major problem is that tumor tissue specimens used to assay these genetic biomarkers are not always available, especially in the early stages of the disease. Therefore, exhaled breath condensates (EBC) could represent a good non-invasive source to allow the evaluation of these important genetic markers; these could help in the diagnosis, follow-up of the disease and/or assessment of treatment efficacy. The key aims of this review are first to describe the origin and constituents of EBC, as well as the different methodological procedures used in studying EBC biomarkers, and second, to document genetic and epigenetic markers that have been analyzed in EBC from lung cancer patients and to estimate their diagnostic and prognostic value. © 2016 Wiley Periodicals, Inc.


Assuntos
Biomarcadores Tumorais/genética , Testes Respiratórios/métodos , Epigenômica , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/genética , Expiração , Humanos
11.
Sci Rep ; 6: 27043, 2016 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-27245205

RESUMO

Normal tissue toxicity after radiotherapy shows variability between patients, indicating inter-individual differences in radiosensitivity. Genetic variation probably contributes to these differences. The aim of the present study was to determine if two cell lines, one radiosensitive (RS) and another radioresistant (RR), showed differences in DNA repair capacity, cell viability, cell cycle progression and, in turn, if this response could be characterised by a differential gene expression profile at different post-irradiation times. After irradiation, the RS cell line showed a slower rate of γ-H2AX foci disappearance, a higher frequency of incomplete chromosomal aberrations, a reduced cell viability and a longer disturbance of the cell cycle when compared to the RR cell line. Moreover, a greater and prolonged transcriptional response after irradiation was induced in the RS cell line. Functional analysis showed that 24 h after irradiation genes involved in "DNA damage response", "direct p53 effectors" and apoptosis were still differentially up-regulated in the RS cell line but not in the RR cell line. The two cell lines showed different response to IR and can be distinguished with cell-based assays and differential gene expression analysis. The results emphasise the importance to identify biomarkers of radiosensitivity for tailoring individualized radiotherapy protocols.


Assuntos
Linfócitos B/efeitos da radiação , Ciclo Celular/efeitos da radiação , Reparo do DNA/efeitos da radiação , Regulação da Expressão Gênica/efeitos da radiação , Transcrição Gênica/efeitos da radiação , Adaptação Fisiológica , Linfócitos B/citologia , Linfócitos B/metabolismo , Ciclo Celular/genética , Morte Celular/efeitos da radiação , Linhagem Celular Transformada , Sobrevivência Celular/efeitos da radiação , Dano ao DNA , Relação Dose-Resposta à Radiação , Raios gama/efeitos adversos , Perfilação da Expressão Gênica , Histonas/genética , Histonas/metabolismo , Humanos , Anotação de Sequência Molecular , Tolerância a Radiação , Transdução de Sinais , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo
12.
J Mol Diagn ; 18(4): 471-9, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27155048

RESUMO

Detection of driver gene mutations in stool DNA represents a promising noninvasive approach for screening colorectal cancer (CRC). Amplicon-based next-generation sequencing (NGS) is a good option to study mutations in many cancer genes simultaneously and from a low amount of DNA. Our aim was to assess the feasibility of identifying mutations in 22 cancer driver genes with Ion Torrent technology in stool DNA from a series of 65 CRC patients. The assay was successful in 80% of stool DNA samples. NGS results showed 83 mutations in cancer driver genes, 29 hotspot and 54 novel mutations. One to five genes were mutated in 75% of cases. TP53, KRAS, FBXW7, and SMAD4 were the top mutated genes, consistent with previous studies. Of samples with mutations, 54% presented concomitant mutations in different genes. Phosphatidylinositol 3-kinase/mitogen-activated protein kinase pathway genes were mutated in 70% of samples, with 58% having alterations in KRAS, NRAS, or BRAF. Because mutations in these genes can compromise the efficacy of epidermal growth factor receptor blockade in CRC patients, identifying mutations that confer resistance to some targeted treatments may be useful to guide therapeutic decisions. In conclusion, the data presented herein show that NGS procedures on stool DNA represent a promising tool to detect genetic mutations that could be used in the future for diagnosis, monitoring, or treating CRC.


Assuntos
Neoplasias Colorretais/diagnóstico , Neoplasias Colorretais/genética , Fezes , Sequenciamento de Nucleotídeos em Larga Escala , Mutação , Oncogenes , Biomarcadores Tumorais , Análise Mutacional de DNA/métodos , Receptores ErbB/genética , Genes ras , Humanos
13.
Int J Radiat Biol ; 91(12): 915-24, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26489383

RESUMO

PURPOSE: The number of radio-induced double-strand breaks is correlated with the number of histone gamma-H2AX (γ-H2AX) foci. For this reason, foci quantification is a useful tool to measure radiation-induced DNA damage and the number of foci has been suggested as a predictive biomarker of radiosensitivity. The aim of the present study was to evaluate the reproducibility of different microscopic methodologies and flow cytometry analysis to score γ-H2AX induction, and its suitability to distinguish a radiosensitive (RS) cell line from a radioresistant (RR) one. MATERIALS AND METHODS: γ-H2AX analyses were performed by semi-automated and automated microscopic methods and by flow cytometry before and after irradiation in two human lymphoblastoid cell lines and in lymphocytes from three healthy donors. RESULTS: Reproducible results were obtained by all the methodologies tested, although not all showed the same sensitivity. The RS cell line always showed higher foci counts and higher levels of immunofluorescence intensity after irradiation than the RR cell line. CONCLUSIONS: Our results suggest that microscopic methodologies with z-stage capacity give the most accurate results after 1 Gy irradiation. However, for high doses of ionizing radiation, flow cytometry gives reliable results. Further studies will be necessary to determine the usefulness of γ-H2AX analysis to predict adverse side reactions in radiotherapy patients.


Assuntos
Citometria de Fluxo/métodos , Histonas/metabolismo , Microscopia Confocal/métodos , Microscopia de Fluorescência/métodos , Tolerância a Radiação , Linhagem Celular Tumoral , Humanos , Processamento de Imagem Assistida por Computador , Linfócitos/metabolismo , Linfócitos/efeitos da radiação , Fosforilação/efeitos da radiação
14.
Lung ; 193(2): 303-8, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25680416

RESUMO

Lung carcinoids are rare neuroendocrine tumors of the lung. Very little is known about the genetic background of these tumors. We applied Ion Torrent Ampliseq next-generation technology to study hotspot mutations of 22 lung cancer-related genes from typical and atypical lung carcinoid tumors. DNA isolated from 25 formalin-fixed, paraffin-embedded carcinoid tumors were amplified to prepare barcoded libraries covering 507 mutations included in 90 amplicons. The libraries were pooled, purified, enriched, and sequenced on ion personal genome machine. The sequences were aligned and checked for known and novel variations using Torrent Suite Software v.4.0.2. One out of 25 patients had mutations in the targeted regions sequenced. This patient had mutations in BRAF, SMAD4, PIK3CA, and KRAS. All these mutations were confirmed as somatic and are previously known mutations. In summary, mutations in genes commonly mutated in non-small-cell lung cancer are not common in lung carcinoids.


Assuntos
Tumor Carcinoide/genética , Carcinoma Pulmonar de Células não Pequenas/genética , DNA de Neoplasias/análise , Genes Neoplásicos/genética , Neoplasias Pulmonares/genética , Adulto , Idoso , Análise Mutacional de DNA/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mutação
15.
Biomark Cancer ; 7(Suppl 1): 39-48, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26793011

RESUMO

Colorectal cancer (CRC) is the third most common malignancy and the second most common cause of cancer death worldwide. Early detection of CRC can improve patient survival rates; thus, the identification of noninvasive diagnostic markers is urgently needed. MicroRNAs (miRNAs) have extensive potential to diagnose several diseases, including cancer. In this study, we compared the expression pattern of miRNAs from plasma and stool samples of patients with early stages of CRC (I, II) with that of healthy subjects. We performed miRNA profiling using microarrays on plasma and stool samples of eight patients with CRC and four healthy subjects. Seven miRNAs were found to be underexpressed in both plasma and stool samples of patients with CRC versus healthy subjects. Then, we aimed to verify two out of these seven differentially expressed miRNAs (let-7a-5p and let-7f-5p) by quantitative reverse transcriptase polymerase chain reaction on a larger set of plasma and stool samples of 51 patients with CRC and 26 healthy subjects. We confirmed the results of microarray analysis since their expression was significantly lower in stool and plasma samples of patients with CRC. Moreover, receiver operating characteristic curve analysis demonstrated that fecal let-7f expression levels have significant sensitivity and specificity to distinguish between patients with CRC and healthy subjects. In conclusion, if the results are confirmed in larger series of patients, underexpressed let-7a-5p and let-7f-5p miRNAs in both plasma and stool samples of patients with CRC may serve potentially as noninvasive molecular biomarkers for the early detection of CRC.

17.
Oncol Rep ; 27(1): 225-31, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21922152

RESUMO

Translational control is a crucial component of cancer development and progression. Eukaryotic initiation factor (eIF) 4E mediates eIF4F association with the mRNA 5' cap structure to stimulate cap-dependent translation initiation. The eIF4E-binding protein, 4E-BP1, regulates cap-dependent translation through its phosphorylation at multiple sites. It has been described that some human carcinomas present a high level of p-4E-BP1, not always associated with high levels of p-mTOR. These previous observations suggest that other kinases could be involved in 4E-BP1 phosporylation. Investigation in new kinases that could be implicated in 4E-BP1 phosphorylation and mechanisms that affect 4E-BP1 stability is important to understand the role of eIF4E in cell transformation. In this study, we examined 48 kinases that could be involved in 4E-BP1 phosphorylation and stability. The screening study was based on analysis of 4E-BP1 status after inhibition of these kinases in a breast carcinoma cell line. Several kinases affecting 4E-BP1 stability (LRRK2, RAF-1, p38γ, GSK3ß, AMPKα, PRKACA and PRKACB) and 4E-BP1 phosphorylation (CDK1, PDK1, SRC, PRKCB1, PAK2, p38ß, PRKCA and CaMKKB) were identified. These findings provide evidence that 4E-BP1 can be regulated and stabilized by multiple kinases implicated in several cell signaling pathways. We focus on the finding that LRRK2 down-regulation was associated with a clearly decreased 4E-BP1 protein (and not with mRNA down-regulation). Importantly, knockdown of LRRK2 associated with high proliferative rate in normal cells and treatment with rapamycin and/or proteosome inhibition suppressed 4E-BP1 protein degradation. These results offer new insights into the regulation of total and phosphorylated 4E-BP1.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Transformação Celular Neoplásica/metabolismo , Neoplasias/metabolismo , Fosfoproteínas/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Western Blotting , Proteínas de Ciclo Celular , Feminino , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina , Fosforilação , Estabilidade Proteica , RNA Interferente Pequeno , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais
18.
Int J Oncol ; 39(5): 1337-45, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21750861

RESUMO

Cell signaling pathways and protein translation are crucial for understanding malignant transformation. 4E-BP1 and the eIF4F complex regulate cap-dependent translation. We investigated how 4E-BP1 and eIF4E phosphorylation status affects in vitro and in vivo cell proliferation in a breast cancer model. Cells from 2 breast carcinoma lines (MDA-MB 231 and MDA-MB 468) and human fibroblasts (IMR90 cells) were infected in vitro with a retrovirus carrying a wild-type 4E-BP1 or a mutant 4E-BP1 unable to hyperphosphorylate. Overexpression of the mutant 4E-BP1 induced a significant decrease in cell proliferation in IMR90 and MDA-MB 468 cells, but not in MDA-MB 231 cells. A correlation was observed between baseline-phosphorylated eIF4E (p-eIF4E) levels and sensitivity to 4E-BP1 transduction. By co-immunoprecipitation, p-eIF4E seemed to present lower affinity for 4E-BP1 than total eIF4E in MDA-MB 468 cells. After treatment with CGP57380, the MAP kinase-interacting kinase (MNK) inhibitor, downregulation of p-eIF4E levels was associated with an increase of E-cadherin and ß-catenin protein expression. These results provide evidence that 4E-BP1 transduction leads to a decrease in cell proliferation, and that high p-eIF4E levels may counteract the suppressor effect of 4E-BP1. We propose that high p-4E-BP1 and p-eIF4E levels are central factors in cell signaling and reflect the oncogenic potential of cell signaling pathways in breast cancer.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Neoplasias da Mama/metabolismo , Fator de Iniciação 4E em Eucariotos/metabolismo , Fosfoproteínas/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Neoplasias da Mama/genética , Proteínas de Ciclo Celular , Linhagem Celular Tumoral , Proliferação de Células , Modelos Animais de Doenças , Fator de Iniciação 4E em Eucariotos/genética , Feminino , Expressão Gênica , Humanos , Camundongos , Camundongos Nus , Complexos Multiproteicos/metabolismo , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Fosfoproteínas/genética , Fosforilação , Ligação Proteica , Transdução de Sinais , Carga Tumoral/genética , Ensaios Antitumorais Modelo de Xenoenxerto
19.
Carcinogenesis ; 32(4): 470-6, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21239520

RESUMO

p90 Ribosomal S6 kinase (RSK) 4 is a serine-threonine kinase that belongs to the p90RSK family. RSK4 has been proposed as a tumor suppressor gene, related with anti-invasive activity, inhibition of the RAS-mitogen-activated protein kinase (MAPK) pathway and induction of senescence. Despite the related findings, little is known about RSK4 effectors. In human tumors, RSK4 is downregulated even in some benign lesions, such as colon adenomas and breast papillomas, indicating that RSK4 inhibition could be an early event in cellular transformation. For cells to achieve immortality and transformation, it is believed that they must override senescence. In the present study, we found that when RSK4 is inhibited in vitro using short hairpin RNA technology, cells can bypass stress-induced senescence and oncogene-induced senescence: normal human fibroblasts grew following oxidative stress, induction of DNA damage and KRAS(V12) or BRAF(E600) overexpression. To investigate the RSK4 effectors, we used short hairpin RNA or inhibitor molecules against major senescence mediators. We found that RSK4-induced senescence is mediated through p21, but is independent of p16, p38MAPKs and induction of reactive oxygen species, delimiting RSK4 signaling. These data support the importance of RSK4 for regulating senescence and indicate that downregulation of this kinase could be an important element in facilitating cell transformation.


Assuntos
Senescência Celular , Oncogenes , Proteínas Quinases S6 Ribossômicas 90-kDa/antagonistas & inibidores , Estresse Fisiológico , Células Cultivadas , Inibidor de Quinase Dependente de Ciclina p21/antagonistas & inibidores , Inibidor de Quinase Dependente de Ciclina p21/fisiologia , Humanos , Proteínas Proto-Oncogênicas B-raf/fisiologia , Proteínas Quinases S6 Ribossômicas 90-kDa/fisiologia , Proteína Supressora de Tumor p53/fisiologia , Proteínas Quinases p38 Ativadas por Mitógeno/fisiologia
20.
Leuk Lymphoma ; 51(1): 114-24, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20001230

RESUMO

We studied a series of 68 subjects diagnosed with childhood acute myeloid leukemia (AML) using conventional cytogenetics and fluorescence in situ hybridization (FISH), polymerase chain reaction (PCR) to analyze mutations in FLT3 and NPM1 genes, and/or array comparative genomic hybridization (CGH). Cytogenetic/FISH abnormalities were observed in 71% of subjects, FLT3-ITD mutations in 15%, and NPM1 mutations in 13%. The array CGH alterations (average 3.6 per case) were observed in 96% of the tested subjects. The most frequent alterations were gains of 8q24.3 and 11p15.5-p15.4 in 16% of the samples. Six genes (AKT1, RUNX1, LTB, SDC1, RUNX1T1, and JAK2) from the imbalanced regions have been reported to be involved in AML, whereas other 30 cancer genes, not previously reported in an AML context, were identified as imbalanced. They probably correspond to non passenger alterations that cooperate with the recurrent translocations. The clinical data and genetic changes were tested to find out the possible association with prognosis. Genomic instability (four or more genomic imbalances) was correlated with poor patient outcome (p = 0.029).


Assuntos
Dosagem de Genes , Leucemia Mieloide Aguda/genética , Mutação , Adolescente , Células da Medula Óssea/citologia , Criança , Pré-Escolar , Citogenética , Feminino , Humanos , Hibridização in Situ Fluorescente , Lactente , Recém-Nascido , Cariotipagem , Leucemia Mieloide Aguda/diagnóstico , Leucemia Mieloide Aguda/terapia , Masculino , Nucleofosmina , Reação em Cadeia da Polimerase , Prognóstico , Translocação Genética
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