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1.
Fluids Barriers CNS ; 17(1): 37, 2020 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-32487241

RESUMO

BACKGROUND: Pediatric diffuse intrinsic pontine glioma (DIPG) represents one of the most devastating and lethal brain tumors in children with a median survival of 12 months. The high mortality rate can be explained by the ineligibility of patients to surgical resection due to the diffuse growth pattern and midline localization of the tumor. While the therapeutic strategies are unfortunately palliative, the blood-brain barrier (BBB) is suspected to be responsible for the treatment inefficiency. Located at the brain capillary endothelial cells (ECs), the BBB has specific properties to tightly control and restrict the access of molecules to the brain parenchyma including chemotherapeutic compounds. However, these BBB specific properties can be modified in a pathological environment, thus modulating brain exposure to therapeutic drugs. Hence, this study aimed at developing a syngeneic human blood-brain tumor barrier model to understand how the presence of DIPG impacts the structure and function of brain capillary ECs. METHODS: A human syngeneic in vitro BBB model consisting of a triple culture of human (ECs) (differentiated from CD34+-stem cells), pericytes and astrocytes was developed. Once validated in terms of BBB phenotype, this model was adapted to develop a blood-brain tumor barrier (BBTB) model specific to pediatric DIPG by replacing the astrocytes by DIPG-007, -013 and -014 cells. The physical and metabolic properties of the BBTB ECs were analyzed and compared to the BBB ECs. The permeability of both models to chemotherapeutic compounds was evaluated. RESULTS: In line with clinical observation, the integrity of the BBTB ECs remained intact until 7 days of incubation. Both transcriptional expression and activity of efflux transporters were not strongly modified by the presence of DIPG. The permeability of ECs to the chemotherapeutic drugs temozolomide and panobinostat was not affected by the DIPG environment. CONCLUSIONS: This original human BBTB model allows a better understanding of the influence of DIPG on the BBTB ECs phenotype. Our data reveal that the chemoresistance described for DIPG does not come from the development of a "super BBB". These results, validated by the absence of modification of drug transport through the BBTB ECs, point out the importance of understanding the implication of the different protagonists in the pathology to have a chance to significantly improve treatment efficiency.

2.
Sci Rep ; 10(1): 7720, 2020 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-32382084

RESUMO

Genome dynamics was investigated within natural populations of the soil bacterium Streptomyces. The exploration of a set of closely related strains isolated from micro-habitats of a forest soil exhibited a strong diversity of the terminal structures of the linear chromosome, i.e. terminal inverted repeats (TIRs). Large insertions, deletions and translocations could be observed along with evidence of transfer events between strains. In addition, the telomere and its cognate terminal protein complexes required for terminal replication and chromosome maintenance, were shown to be variable within the population probably reflecting telomere exchanges between the chromosome and other linear replicons (i.e., plasmids). Considering the close genetic relatedness of the strains, these data suggest that the terminal regions are prone to a high turnover due to a high recombination associated with extensive horizontal gene transfer.


Assuntos
Cromossomos Bacterianos/genética , Replicação do DNA/genética , Streptomyces/genética , Telômero/genética , Sequência de Aminoácidos/genética , Variação Genética , Plasmídeos/genética , Recombinação Genética/genética , Replicon/genética , Microbiologia do Solo , Sequências Repetidas Terminais/genética
3.
Pediatr Blood Cancer ; 67(2): e28086, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31738008

RESUMO

INTRODUCTION: Pediatric adrenal cortical tumors are characterized by a wide spectrum of behavior. Questions remain regarding intermediate disease stages with isolated tumor rupture or relapse. OBJECTIVES: To describe clinical characteristics, treatment strategy, and outcome of patients depending on disease stage, tumor rupture, or in case of a refractory tumor, to discuss optimal management. MATERIAL AND METHODS: Pediatric patients with histological material reviewed and treated between 2000 and 2018 in 23 French oncology centers were included. RESULTS: Among 95 cases, 59% of patients had stage I tumors (n = 55), 16% had stage II tumors (n = 16), 19% had stage III tumors (n = 17), and 5% had stage IV tumors (n = 5) (missing data: 2). Overall, 27% of patients (n = 25) had an unfavorable histology. Initial tumor resection was performed for 90% of patients (n = 86). Systemic therapies included mitotane in 20 cases and chemotherapy in 13 cases. Among 17 stage III patients, 12 had microscopic residual tumor due to an initial biopsy (n = 5), intraoperative rupture (n = 8), or surgical resection with microscopic residue or tumor spillage surgery (n = 1) (two patients with two modalities). After a median follow-up of 96 months (25-119), four early progressions and two relapses occurred. A total of seven patients died, including five of disease. Stage III diseases due to microscopic residual disease correlated with a worse prognosis: 5-year progression-free survival 44% (95% CI, 22-87%) versus 82% (95% CI, 73-91%) for the whole cohort (P < .0001). Among the 14 patients with refractory disease, only 3 were alive and free of disease after multimodal second-line therapy. CONCLUSIONS: Stage III diseases due to a microscopic residual tumor have a dismal prognosis, arguing for the systematic use of adjuvant therapy. Patients with a relapsed disease should be included in experimental studies.


Assuntos
Neoplasias do Córtex Suprarrenal/classificação , Neoplasias do Córtex Suprarrenal/patologia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Resistencia a Medicamentos Antineoplásicos , Recidiva Local de Neoplasia/patologia , Neoplasia Residual/patologia , Terapia de Salvação , Adolescente , Neoplasias do Córtex Suprarrenal/terapia , Criança , Pré-Escolar , Terapia Combinada , Feminino , Seguimentos , Humanos , Lactente , Masculino , Recidiva Local de Neoplasia/terapia , Neoplasia Residual/terapia , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida
4.
Neuro Oncol ; 22(1): 128-138, 2020 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-31504825

RESUMO

BACKGROUND: Medulloblastomas may occur in a predisposition context, including familial adenomatosis polyposis. Medulloblastomas related to a germline pathogenic variant of adenomatous polyposis coli (APC) remain rare and poorly described. Their similarities with sporadic WNT medulloblastomas still require description. METHODS: We performed a multicentric retrospective review of 12 patients treated between 1988 and 2018 for medulloblastoma with an identified or highly suspected (personal or familial history) APC germline pathogenic variant. We report personal and familial history APC gene pathogenic variants whenever available: clinical and histologic characteristics of the medulloblastoma, treatments, and long-term outcome, including second tumor and late sequelae. RESULTS: Medulloblastomas associated with APC pathogenic variants are mainly classic (11/11 patients, 1 not available), nonmetastatic (10/12 patients) medulloblastomas, with nuclear immunoreactivity for ß-catenin (9/9 tested cases). Ten of 11 assessable patients are disease free with a median follow-up of 10.7 years (range, 1-28 y). Secondary tumors included desmoid tumors in 7 patients (9 tumors), 1 thyroid carcinoma, 2 pilomatricomas, 1 osteoma, 1 vertebral hemangioma, and 1 malignant triton in the radiation field, which caused the only cancer-related death in our series. CONCLUSIONS: Medulloblastomas associated with an APC pathogenic variant have an overall favorable outcome, even for metastatic tumors. Yet, long-term survival is clouded by second tumor occurrence; treatment may play some role in some of these second malignancies. Our findings raise the question of applying a de-escalation therapeutic protocol to treat patients with APC germline pathogenic variants given the excellent outcome, and reduced intensity of craniospinal irradiation may be further evaluated.

5.
Pediatr Blood Cancer ; 67(1): e28032, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31595663

RESUMO

AIM: To assess objective response after two cycles of temozolomide and topotecan (TOTEM) in children with refractory or relapsed miscellaneous extracranial solid and central nervous system (CNS) tumors, including medulloblastoma and primitive neuroectodermal tumors (PNET). PROCEDURE: Multicenter, nonrandomized, phase 2 basket trial including children with solid tumors, completed by a one-stage design confirmatory cohort for medulloblastoma, and an exploratory cohort for PNET. Main eligibility criteria were refractory/relapsed measurable disease and no more than two prior treatment lines. Temozolomide was administered orally at 150 mg/m2 /day followed by topotecan at 0.75 mg/m2 /day intravenously for five consecutive days every 28 days. Tumor response was assessed every two cycles according to WHO criteria and reviewed independently. RESULTS: Thirty-two patients were enrolled and treated in the miscellaneous solid tumor and 33 in the CNS strata; 20 patients with medulloblastoma and six with PNET were included in the expansion cohorts. The median age at inclusion was 10.0 years (range, 0.9-20.9). In the basket cohorts, confirmed complete and partial responses were observed in one glioma, four medulloblastoma, and one PNET, leading to the extension. The overall objective response rate (ORR) in medulloblastoma was 28% (95% CI, 12.7-47.2) with 1/29 complete and 7/29 partial responses, those for PNET 10% (95% CI, 0.3-44.5). Post hoc Bayesian analysis estimates that the true ORR in medulloblastoma is probably between 20% and 30% and below 20% in PNET. The most common treatment-related toxicities of the combination therapy were hematologic. CONCLUSIONS: Temozolomide-topotecan results in significant ORR in children with recurrent and refractory medulloblastoma with a favorable toxicity profile.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias do Sistema Nervoso Central/tratamento farmacológico , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Meduloblastoma/tratamento farmacológico , Recidiva Local de Neoplasia/tratamento farmacológico , Tumores Neuroectodérmicos Primitivos/tratamento farmacológico , Terapia de Salvação , Adolescente , Adulto , Teorema de Bayes , Neoplasias do Sistema Nervoso Central/patologia , Neoplasias Cerebelares/tratamento farmacológico , Neoplasias Cerebelares/patologia , Criança , Pré-Escolar , Feminino , Seguimentos , Humanos , Lactente , Masculino , Meduloblastoma/patologia , Recidiva Local de Neoplasia/patologia , Tumores Neuroectodérmicos Primitivos/patologia , Prognóstico , Taxa de Sobrevida , Temozolomida/administração & dosagem , Topotecan/administração & dosagem , Adulto Jovem
6.
Brain Pathol ; 30(1): 179-190, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31348837

RESUMO

Pediatric diffuse midline gliomas are devastating diseases. Among them, diffuse midline gliomas H3K27M-mutant are associated with worse prognosis. However, recent studies have highlighted significant differences in clinical behavior and biological alterations within this specific subgroup. In this context, simple markers are needed to refine the prognosis of diffuse midline gliomas H3K27M-mutant and guide the clinical management of patients. The aims of this study were (i) to describe the molecular, immunohistochemical and, especially, chromosomal features of a cohort of diffuse midline gliomas and (ii) to focus on H3K27M-mutant tumors to identify new prognostic markers. Patients were retrospectively selected from 2001 to 2017. Tumor samples were analyzed by immunohistochemistry (including H3K27me3, EGFR, c-MET and p53), next-generation sequencing and comparative genomic hybridization array. Forty-nine patients were included in the study. The median age at diagnosis was 9 years, and the median overall survival (OS) was 9.4 months. H3F3A or HIST1H3B mutations were identified in 80% of the samples. Within the H3K27M-mutant tumors, PDGFRA amplification, loss of 17p and a complex chromosomal profile were significantly associated with worse survival. Three prognostic markers were identified in diffuse midline gliomas H3K27M-mutant: PDGFRA amplification, loss of 17p and a complex chromosomal profile. These markers are easy to detect in daily practice and should be considered to refine the prognosis of this entity.


Assuntos
Glioma/genética , Glioma/patologia , Adolescente , Neoplasias Encefálicas/patologia , Criança , Pré-Escolar , Estudos de Coortes , Hibridização Genômica Comparativa/métodos , Feminino , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Histonas/genética , Humanos , Imuno-Histoquímica/métodos , Lactente , Masculino , Mutação , Prognóstico , Estudos Retrospectivos , Adulto Jovem
7.
mBio ; 10(5)2019 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-31481382

RESUMO

In this work, by comparing genomes of closely related individuals of Streptomyces isolated at a spatial microscale (millimeters or centimeters), we investigated the extent and impact of horizontal gene transfer in the diversification of a natural Streptomyces population. We show that despite these conspecific strains sharing a recent common ancestor, all harbored significantly different gene contents, implying massive and rapid gene flux. The accessory genome of the strains was distributed across insertion/deletion events (indels) ranging from one to several hundreds of genes. Indels were preferentially located in the arms of the linear chromosomes (ca. 12 Mb) and appeared to form recombination hot spots. Some of them harbored biosynthetic gene clusters (BGCs) whose products confer an inhibitory capacity and may constitute public goods that can favor the cohesiveness of the bacterial population. Moreover, a significant proportion of these variable genes were either plasmid borne or harbored signatures of actinomycete integrative and conjugative elements (AICEs). We propose that conjugation is the main driver for the indel flux and diversity in Streptomyces populations.IMPORTANCE Horizontal gene transfer is a rapid and efficient way to diversify bacterial gene pools. Currently, little is known about this gene flux within natural soil populations. Using comparative genomics of Streptomyces strains belonging to the same species and isolated at microscale, we reveal frequent transfer of a significant fraction of the pangenome. We show that it occurs at a time scale enabling the population to diversify and to cope with its changing environment, notably, through the production of public goods.


Assuntos
Transferência Genética Horizontal , Genes Bacterianos/genética , Variação Genética , Streptomyces/genética , Actinobacteria/genética , Vias Biossintéticas/genética , Cromossomos Bacterianos , Conjugação Genética , DNA Bacteriano/genética , Genoma Bacteriano , Família Multigênica , Tipagem de Sequências Multilocus , Filogenia , Plasmídeos
8.
Microbiol Resour Announc ; 8(38)2019 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-31537669

RESUMO

The genomes of 11 conspecific Streptomyces strains, i.e., from the same species and inhabiting the same ecological niche, were sequenced and assembled. This data set offers an ideal framework to assess the genome evolution of Streptomyces species in their ecological context.

9.
Cancer Causes Control ; 30(10): 1075-1085, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31399828

RESUMO

PURPOSE: Although some specific genetic syndromes such as neurofibromatosis (NF) have been identified as risk factor of childhood brain tumors (CBT), the potential role of inherited susceptibility in CBT has yet to be elucidated. METHODS: To further investigate this, we conducted a pooled analysis of two nationwide case-control studies ESCALE and ESTELLE. The mothers of 509 CBT cases and 3,102 controls aged under 15 years who resided in France at diagnosis/interview, frequency-matched by age and gender, responded to a telephone interview conducted by trained interviewers. Pooled odds ratio (OR) and 95% confidence intervals (95% CI) were estimated using unconditional logistic regression. RESULTS: CBT was significantly associated with the family history of cancer in relatives (OR 1.2, 95% CI 1.0-1.5). The OR was slightly higher for maternal relatives than for paternal relatives, and when at least two relatives had a history of cancer. CBT was significantly associated with a family history of brain tumor (OR 2.1, 95% CI 1.3-3.7). This association seemed stronger for first-degree relatives (mother, father, and siblings), for whom, by contrast, no association was seen for cancers other than CBT. No specificity by CBT subtypes or by age of the children were found for any of these findings. CONCLUSION: Our findings support the hypothesis of a familial susceptibility of CBT, not due to being a known NF carrier.


Assuntos
Suscetibilidade a Doenças , Família , Neoplasias/epidemiologia , Adolescente , Adulto , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , França/epidemiologia , Humanos , Modelos Logísticos , Masculino , Anamnese , Razão de Chances , Fatores de Risco
10.
Mol Diagn Ther ; 23(4): 537-545, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31087282

RESUMO

BACKGROUND AND OBJECTIVE: Genomic duplications and fusion involving BRAF and KIAA1549 that create fusion proteins with constitutive B-RAF kinase activity are a hallmark of pilocytic astrocytomas (PAs). The detection of KIAA1549-BRAF fusion transcripts is of paramount importance to classify these tumors and to identify patients who could benefit from BRAF inhibitors. In a clinical setting, the available material for molecular analysis from these pediatric tumors is often limited to formalin-fixed paraffin-embedded (FFPE) tissue. The aim of the present study was to develop a new method to detect the three most frequent KIAA1549-BRAF fusion transcripts, 15-9, 16-11, and 16-9, where numbers refer to the exons fused together, using a FFPE-compatible multiplex quantitative reverse transcription polymerase chain reaction (qRT-PCR). METHODS: We compared performance of the assay to a reference singleplex method on a collection of 46 FFPE PAs. RESULTS: The results showed that both methods are comparable. The multiplex method had an overall 97% sensitivity and 100% specificity compared to the singleplex method, and agreement between the two techniques was almost perfect (Cohen's kappa: 0.97). There was no evidence of a significant difference between the qRT-PCR efficiencies of the multiplex technique and of the singleplex assay for all fusion transcripts and for GAPDH, the latter used as a reference gene. The multiplex method consumed four times less complementary DNA (cDNA), cost less, and required half the hands-on technical time. CONCLUSION: The results show that it could be beneficial to implement the multiplex method in a clinical setting, where samples presenting low quantity of degraded RNA are not unusual.


Assuntos
Astrocitoma/genética , Reação em Cadeia da Polimerase Multiplex , Proteínas de Fusão Oncogênica/genética , Reação em Cadeia da Polimerase em Tempo Real , Adolescente , Astrocitoma/diagnóstico , Biópsia , Análise Custo-Benefício , Feminino , Frequência do Gene , Humanos , Masculino , Reação em Cadeia da Polimerase Multiplex/métodos , Gradação de Tumores , Inclusão em Parafina , Reação em Cadeia da Polimerase em Tempo Real/métodos , Reprodutibilidade dos Testes
11.
Pediatr Blood Cancer ; 66(7): e27693, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30920117

RESUMO

OBJECTIVE: To investigate the antitumor activity of a four-drug metronomic chemotherapy (MC) regimen in relapsed/progressing pediatric extracranial solid tumors (EST). The primary objective was clinical benefit (complete response /partial response/stable disease [SD]) after two cycles of therapy (four months). METHODS: Patients aged ≥4 to 25 years with progressing EST and adequate organ function were eligible. Treatment consisted of an eight-week cycle of oral celecoxib b.i.d., weekly vinblastine, and oral cyclophosphamide for three weeks alternating with oral methotrexate for three weeks, with a two-week rest. The Kepner-Chang two-stage model was used with 10 patients in the first stage. If primary objective was reached in two or more patients, eight additional patients were included according to four groups: neuroblastoma (NBL), soft-tissue sarcoma (STS), bone sarcoma (BS), and miscellaneous (Misc.). RESULTS: Forty-four patients were evaluable. The NBL cohort could be expanded to 18 patients: 4 of 18 patients stabilized with MC treatment for 6 (n = 1) and 12 (n = 3) months. In STS, two of seven patients (metastatic hemangioendothelioma and angiosarcoma) had SD for > 2 cycles. One of nine Misc. (metastatic myoepithelial carcinoma) had SD for one year. All patients with BS had progressive disease. One-year progression-free survival of the whole cohort was 6.8% and one-year overall survival was 55.3%. Grade 3 toxicity occurred in 18 patients and grade 4 in 15 patients. The most frequent toxicity was hematologic, predominantly neutropenia. CONCLUSIONS: This MC has no activity in BS and limited though interesting activity in NBL with some patients being stable for > 1 year. It is not possible to conclude activity in STS and Misc.


Assuntos
Administração Metronômica , Celecoxib/administração & dosagem , Modelos Biológicos , Neoplasias/tratamento farmacológico , Adolescente , Adulto , Celecoxib/efeitos adversos , Criança , Pré-Escolar , Intervalo Livre de Doença , Feminino , Humanos , Masculino , Neoplasias/mortalidade , Taxa de Sobrevida
12.
Mol Microbiol ; 111(5): 1139-1151, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30746801

RESUMO

Double-strand breaks (DSBs) are the most detrimental DNA damage encountered by bacterial cells. DBSs can be repaired by homologous recombination thanks to the availability of an intact DNA template or by Non-Homologous End Joining (NHEJ) when no intact template is available. Bacterial NHEJ is performed by sets of proteins of growing complexity from Bacillus subtilis and Mycobacterium tuberculosis to Streptomyces and Sinorhizobium meliloti. Here, we discuss the contribution of these models to the understanding of the bacterial NHEJ repair mechanism as well as the involvement of NHEJ partners in other DNA repair pathways. The importance of NHEJ and of its complexity is discussed in the perspective of regulation through the biological cycle of the bacteria and in response to environmental stimuli. Finally, we consider the role of NHEJ in genome evolution, notably in horizontal gene transfer.


Assuntos
Bactérias/genética , Quebras de DNA de Cadeia Dupla , Reparo do DNA por Junção de Extremidades , Regulação Bacteriana da Expressão Gênica , Transferência Genética Horizontal , Genoma Bacteriano , Recombinação Homóloga
13.
Arch Dis Child ; 104(10): 947-952, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-30472665

RESUMO

OBJECTIVE: To analyse parents' and children's understanding of consent information and assess their decision-making process in paediatric oncology. DESIGN: Prospective observational study. SETTINGS: Eleven French paediatric oncology units. PATIENTS: Parents and children who have been asked to give consent for participation in an early phase trial. INTERVENTIONS: Thirty-seven children and 119 parents were questioned using an audio-recorded semistructured interview. MAIN OUTCOME MEASURES: The participants' understanding of nine elements of the informed consent was assessed by comparing their answers with the informed consent leaflet. Their decision-making process was also evaluated. RESULTS: Most parents and children had an excellent understanding regarding their participation in a clinical trial (respectively 88.2% and 48.6%), the right to withdraw (76.5% and 43.2%) and the prospects of collective benefits (74.8% and 48.6%). By contrast, less than half of the parents and few of the children correctly understood the alternatives (respectively 47.5% and 27%), the risks related to participation (44.5% and 10.8%), the prospects of individual benefits (33.6% and 10.8%) and the purpose of the clinical trial (12.6% and 2.7%). Twenty-six (70.3%) children participated in the decision-making process. Most parents and children felt they had no choice but to participate in the trial to have access to a new anticancer treatment. CONCLUSIONS: What might appear to be a poor understanding of the research protocol may actually correspond to the families' interpretation of the situation as a coping mechanism. All children (except infants) should get age-tailored information in order for them to have a meaningful involvement in research.


Assuntos
Ensaios Clínicos Fase I como Assunto , Compreensão , Tomada de Decisões , Consentimento Livre e Esclarecido , Pais , Participação do Paciente , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Neoplasias/terapia , Estudos Prospectivos
14.
Mod Pathol ; 32(4): 546-559, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30401946

RESUMO

The prognosis of malignant pediatric adrenocortical tumors is closely related to disease stage, which is used to guide perioperative treatment recommendations. However, current scoring systems are inadequate to distinguish between benign and malignant adrenocortical tumors. Robust microscopic prognostic features that could help determine perioperative therapy are also lacking. The aim of this national study was to review the prognostic value of the Wieneke scoring criteria and Ki67 labeling index in unselected pediatric adrenocortical tumors. Using strict definitions previously defined by expert pathologists, a Wieneke score was re-attributed to each tumor after an independent and centralized review. In addition, Ki67 proliferation index was performed and reviewed for each case. A total of 95 cases were selected; all were treated between 2000 and 2018 and had histopathologic material and sufficient outcome-related information available. Localized disease was found in 88% of patients. Among those with advanced disease, 6% had tumor extension into adjacent organs and 5% had metastases at diagnosis. Median follow-up was 5 years and 3 months. The 5-year PFS was 82%, 95% CI [73%-91%]. Tumor stage significantly correlated with PFS (p < 0.0001). Tumor weight up to 200 g, extra-adrenal extension and initial non-complete surgical resection were statistically associated with worse outcomes. No recurrences nor metastases occurred when the Ki67 index was < 15%. Up to two of the following five factors including tumor necrosis, adrenal capsular invasion, venous invasion, mitotic count > 15/20 high-power fields, and Ki67 index > 15%, significantly correlated with worse outcomes. We propose a pathological scoring system incorporating the Ki67 index as part of a two-step approach after disease staging to guide adjuvant treatment in pediatric adrenocortical tumors, especially after incomplete resection. These results should be validated in an independent cohort.


Assuntos
Neoplasias do Córtex Suprarrenal/patologia , Gradação de Tumores/métodos , Adolescente , Biomarcadores Tumorais/análise , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Humanos , Lactente , Recém-Nascido , Antígeno Ki-67/análise , Masculino , Índice Mitótico , Estudos Retrospectivos
15.
Artigo em Inglês | MEDLINE | ID: mdl-30533680

RESUMO

The draft genome of Streptomyces sp. strain ETH9427 was sequenced and assembled into three large scaffolds, a 7.745-Mb linear chromosome with terminal inverted repeats of 201 kb and two probable extrachromosomal elements. Thirty-two biosynthetic gene clusters (BGCs) were identified, out of which four are duplicated in the terminal inverted repeats.

16.
Antibiotics (Basel) ; 7(4)2018 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-30279346

RESUMO

Specialized metabolites are of great interest due to their possible industrial and clinical applications. The increasing number of antimicrobial resistant infectious agents is a major health threat and therefore, the discovery of chemical diversity and new antimicrobials is crucial. Extensive genomic data from Streptomyces spp. confirm their production potential and great importance. Genome sequencing of the same species strains indicates that specialized metabolite biosynthetic gene cluster (SMBGC) diversity is not exhausted, and instead, a pool of novel specialized metabolites still exists. Here, we analyze the genome sequence data from six phylogenetically close Streptomyces strains. The results reveal that the closer strains are phylogenetically, the number of shared gene clusters is higher. Eight specialized metabolites comprise the core metabolome, although some strains have only six core gene clusters. The number of conserved gene clusters common between the isolated strains and their closest phylogenetic counterparts varies from nine to 23 SMBGCs. However, the analysis of these phylogenetic relationships is not affected by the acquisition of gene clusters, probably by horizontal gene transfer events, as each strain also harbors strain-specific SMBGCs. Between one and 15 strain-specific gene clusters were identified, of which up to six gene clusters in a single strain are unknown and have no identifiable orthologs in other species, attesting to the existing SMBGC novelty at the strain level.

17.
Front Pharmacol ; 9: 00950, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30319400

RESUMO

Background: Metronomic chemotherapy (MC) is defined as the frequent administration of chemotherapy at doses below the maximal tolerated dose and with no prolonged drug-free break. MC has shown its efficacy in adult tumor types such as breast and ovarian cancer and has to some extent been studied in pediatrics. Objective: To assess the anti-tumor activity and toxicity of a four-drug metronomic regimen in relapsing/refractory pediatric brain tumors (BT) with progression-free survival (PFS) after two cycles as primary endpoint. Methods: Patients ≥4 to 25 years of age were included with progressing BT. Treatment consisted of an 8-week cycle of celecoxib, vinblastine, and cyclophosphamide alternating with methotrexate. Kepner and Chang two-steps model was used with 10 patients in the first stage. If stabilization was observed in ≥2 patients, 8 additional patients were recruited. Assessment was according WHO criteria with central radiology review. Results: Twenty-nine patients (27 evaluable) were included in two groups: ependymoma (group 1, N = 8), and miscellaneous BT (group 2): 3 medulloblastoma (MB), 5 high grade glioma (HGG), 11 low grade glioma (LGG), 2 other BT. After first stage, recruitment for ependymoma was closed [one patient had stable disease (SD) for 4 months]. Cohort 2 was opened for second stage since 1 HGG and 3 LGG patients had SD after two cycles. Recruitment was limited to LGG for the second stage and 2 partial responses (PR), 6 SD and 2 progressive disease (PD) were observed after two cycles. Of these patients with LGG, median age was 10 years, nine patients received vinblastine previously. Median number of cycles was 6.8 (range: 1-12). Treatment was interrupted in five patients for grade 3/4 toxicity. Conclusion: This regimen is active in patients with LGG, even if patients had previously received vinblastine. Toxicity is acceptable. Trial Registration: This study was registered under clinicaltrials.gov - NCT01285817; EUDRACT nr: 2010-021792-81.

18.
Bioconjug Chem ; 29(7): 2370-2381, 2018 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-29878753

RESUMO

The severe side effects associated with the use of anthracycline anticancer agents continues to limit their use. Herein we describe the synthesis and preliminary biological evaluation of three enzymatically activatable doxorubicin-oligosaccharide prodrugs. The synthetic protocol allows late stage variation of the carbohydrate and is compatible with the use of disaccharides such as lactose as well as more complex oligosaccharides such as xyloglucan oligomers. The enzymatic release of doxorubicin from the prodrugs by both protease (plasmin) and human carboxylesterases (hCE1 and 2) was demonstrated in vitro and the cytotoxic effect of the prodrugs was assayed on MCF-7 breast cancer cells.


Assuntos
Doxorrubicina/uso terapêutico , Oligossacarídeos/química , Pró-Fármacos/síntese química , Antineoplásicos/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Hidrolases de Éster Carboxílico/metabolismo , Ensaios de Seleção de Medicamentos Antitumorais , Fibrinolisina/metabolismo , Humanos , Células MCF-7 , Pró-Fármacos/metabolismo
19.
Sci Rep ; 8(1): 5272, 2018 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-29588483

RESUMO

The linear chromosome of the bacterium Streptomyces exhibits a remarkable genetic organization with grossly a central conserved region flanked by variable chromosomal arms. The terminal diversity co-locates with an intense DNA plasticity including the occurrence of large deletions associated to circularization and chromosomal arm exchange. These observations prompted us to assess the role of double strand break (DSB) repair in chromosome plasticity following. For that purpose, DSBs were induced along the chromosome using the meganuclease I-SceI. DSB repair in the central region of the chromosome was mutagenic at the healing site but kept intact the whole genome structure. In contrast, DSB repair in the chromosomal arms was mostly associated to the loss of the targeted chromosomal arm and extensive deletions beyond the cleavage sites. While homologous recombination occurring between copies of DNA sequences accounted for the most part of the chromosome rescue events, Non Homologous End Joining was involved in mutagenic repair as well as in huge genome rearrangements (i.e. circularization). Further, NHEJ repair was concomitant with the integration of genetic material at the healing site. We postulate that DSB repair drives genome plasticity and evolution in Streptomyces and that NHEJ may foster horizontal transfer in the environment.


Assuntos
Quebras de DNA de Cadeia Dupla , Reparo do DNA , DNA Bacteriano/genética , Streptomyces/genética , Sequência de Bases , Cromossomos Bacterianos , Reparo do DNA por Junção de Extremidades , Evolução Molecular , Genoma Bacteriano , Mutagênese
20.
Ann Biol Clin (Paris) ; 76(1): 81-95, 2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-29386148

RESUMO

A total of 125 Streptomyces strains were isolated from an Algerian wetland (Fetzara Lake) and characterized by growth on different culture media. Phylogenetic analyses were carried out by 16S rRNA sequence comparison after PCR amplification using universal primers. Antibacterial bioassays performed by the agar diffusion method enabled us to retain 33 Streptomyces isolates for their activity against two Gram-positive bacteria (Bacillus subtilis and Micrococcus luteus) and one Gram-negative bacteria (Escherichia coli). Among them, six isolates inhibited all three indicator strains. Antibacterial compounds were then extracted from the solid culture media with ethanol and ethyl acetate as organic solvents. The minimal inhibitory concentration (% v/v) of the extracts was evaluated by a standardized broth dilution method against different clinical-resistant bacterial isolates and Candida albicans. The most active crude extracts were selected for further characterization by chromatographic analysis (RP-HPLC).


Assuntos
Anti-Infecciosos/metabolismo , Antibiose , Lagos/microbiologia , Streptomyces/genética , Streptomyces/isolamento & purificação , Streptomyces/metabolismo , Argélia , Anti-Infecciosos/farmacologia , Antibiose/genética , Antifúngicos/metabolismo , Antifúngicos/farmacologia , Bacillus subtilis , Técnicas de Tipagem Bacteriana , Candida albicans , Humanos , Testes de Sensibilidade Microbiana , Filogenia , RNA Ribossômico 16S/análise , Streptomyces/classificação , Áreas Alagadas
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