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36 result(s) for "Chastagner, Pascal"
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Radiosensitization with Gadolinium Chelate-Coated Gold Nanoparticles Prevents Aggressiveness and Invasiveness in Glioblastoma
This study aimed to evaluate the radiosensitizing potential of Au@DTDTPA(Gd) nanoparticles when combined with conventional external X-ray irradiation (RT) to treat GBM. Complementary biological models based on U87 spheroids including conventional 3D invasion assay, organotypic brain slice cultures, chronic cranial window model were implemented to investigate the impact of RT treatments (10 Gy single dose; 5×2 Gy or 2×5 Gy) combined with Au@DTDTPA(Gd) nanoparticles on tumor progression. The main tumor mass and its infiltrative area were analyzed. This work focused on the invading cancer cells after irradiation and their viability, aggressiveness, and recurrence potential were assessed using mitotic catastrophe quantification, MMP secretion analysis and neurosphere assays, respectively. In vitro clonogenic assays showed that Au@DTDTPA(Gd) nanoparticles exerted a radiosensitizing effect on U87 cells, and in vivo experiments suggested a benefit of the combined treatment \"RT 2×5 Gy + Au@DTDTPA(Gd)\" compared to RT alone. Invasion assays revealed that invasion distance tended to increase after irradiation alone, while the combined treatments were able to significantly reduce tumor invasion. Monitoring of U87-GFP tumor progression using organotypic cultures or intracerebral grafts confirmed the anti-invasive effect of Au@DTDTPA(Gd) on irradiated spheroids. Most importantly, the combination of Au@DTDTPA(Gd) with irradiation drastically reduced the number, the viability and the aggressiveness of tumor cells able to escape from U87 spheroids. Notably, the combined treatments significantly reduced the proportion of escaped cells with stem-like features that could cause recurrence. Combining Au@DTDTPA(Gd) nanoparticles and X-ray radiotherapy appears as an attractive therapeutic strategy to decrease number, viability and aggressiveness of tumor cells that escape and can invade the surrounding brain parenchyma. Hence, Au@DTDTPA(Gd)-enhanced radiotherapy opens up interesting perspectives for glioblastoma treatment.
Fertility discussions and concerns in childhood cancer survivors, a systematic review for updated practice
Purpose To provide ways to improve the clinical practice of fertility preservation (FP) for children, adolescents, and young adults (AYA) with cancer. Design A systematic research of online databases was undertaken in March 2020 following the PRISMA criteria, including Medline and Web of Science. Results Fifty‐nine articles were included. Surveys, interviews, and focus groups were used to collect data from patients, parents, and health care providers (HCPs). Four themes worth exploring emerged: (a) what do patients and professionals think of and know about FP? (b) what makes the fertility discussion happen or not? (c) what, retrospectively, led to FP being pursued or not? and (d) how do patients and HCPs feel about fertility issues? Conclusion A minority of AYAs preserve their fertility (banking assay for 45% of boys and 23% of girls). Yet fertility concerns have a significant impact on the quality of life of young cancer survivors. Although recommendations and guidelines regarding FP are available internationally, there are no specific guidelines as to how to conduct fertility counseling for children and adolescents. Some barriers are not removable, such as a poor prognosis of an obvious severe disease, time constraints for starting treatment, and cultural and religious beliefs. In response to aspects hindering patients and families to be receptive to any discussion at the time of diagnosis, psychological support could reduce the level of emotional distress and help restore a degree of open‐mindedness to open a window for discussion. Moreover, as the lack of knowledge of professionals about fertility is frequently pointed out as a limiting factor for fertility discussion, reinforcing professional training regarding FP could be proposed to promote fertility discussion and eventually referral for FP. This review studies the mechanisms leading to fertility preservation with a focus on the behavior and psychosocial issues surrounding FP in young cancer survivors, their parents and health care professionals.
Neurocognitive and radiological follow-up of children under 5 years of age treated for medulloblastoma according to the HIT-SKK protocol
Background The HIT-SKK protocol is used for low/standard-risk medulloblastomas in young children with the aim to eliminate cranial irradiation and its neuropsychological (NP) sequelae. This therapy includes IV and intraventricular (ITV) methotrexate (MTX) potentially responsible for leukoencephalopathy (LE) and neurocognitive disorders. This study describes the risk factors and course of LE, and investigates its correlation with neurocognitive impact. Methods A retrospective, multicenter study was conducted in 35 children under 5 years old, with a median follow-up of 72 months (range 14 to 130). The main analysis was performed in 30 patients who received cumulative doses of MTX as per-protocol (group 1). Five patients who received higher cumulative doses of MTX were analyzed separately. All follow-up MRIs and NP assessments were centrally reviewed by experts. Results Twenty patients in group 1 developed LE, grade 2 and 3 abnormalities did not correlate with higher cumulative doses of ITV-MTX (p = 0.698). Considering the most recent NP evaluation, the Full-Scale IQ (FSIQ) and Wechsler indices were in the average to lower average range. The FSIQ was deficient in 6/17 evaluable patients. Cumulative dose of ITV-MTX was almost associated with decreased processing speed competence (p = 0.055) which was the most frequently impaired neurocognitive domain. Neuropsychological assessment scores were not statistically lower in patients with persistent grade 2 LE at the end of follow-up. Conclusion This study described that the use of cumulative dose of MTX (IV and ITV) according to the HIT-SKK protocol resulted in LE that tented to decrease over time, without significant correlation with a decline in neuro-intellectual skills.
NRP1 inhibition modulates radiosensitivity of medulloblastoma by targeting cancer stem cells
Background Medulloblastoma (MB) is the most common pediatric malignant brain tumor. Despite current therapies, the morbidity and recurrent risk remains significant. Neuropilin-1 receptor (NRP1) has been implicated in the tumor progression of MB. Our recent study showed that NRP1 inhibition stimulated MB stem cells differentiation. Consequently, we hypothesized that targeting NRP1 in medulloblastoma could improve current treatments. Methods NRP1 inhibition with a novel peptidomimetic agent, MR438, was evaluated with radiotherapy (RT) in MB models (DAOY, D283-Med and D341-Med) in vitro on cancer stem-like cells as well as in vivo on heterotopic and orthotopic xenografts. Results We show that NRP1 inhibition by MR438 radiosensitizes MB stem-like cells in vitro. In heterotopic DAOY models, MR438 improves RT efficacy as measured by tumor growth and mouse survival. In addition, clonogenic assays after tumor dissociation showed a significant reduction in cancer stem cells with the combination treatment. In the same way, a benefit of the combined therapy was observed in the orthotopic model only for a low cumulative irradiation dose of 10 Gy but not for 20 Gy. Conclusions Finally, our results demonstrated that targeting NRP1 with MR438 could be a potential new strategy and could limit MB progression by decreasing the stem cell number while reducing the radiation dose.
Childhood Langerhans cell histiocytosis with severe lung involvement: a nationwide cohort study
Background Lung involvement in childhood Langerhans cell histiocytosis (LCH) is infrequent and rarely life threatening, but occasionally, severe presentations are observed. Methods Among 1482 children (< 15 years) registered in the French LCH registry (1994–2018), 111 (7.4%) had lung involvement. This retrospective study included data for 17 (1.1%) patients that required one or more intensive care unit (ICU) admissions for respiratory failure. Results The median age was 1.3 years at the first ICU hospitalization. Of the 17 patients, 14 presented with lung involvement at the LCH diagnosis, and 7 patients (41%) had concomitant involvement of risk-organ (hematologic, spleen, or liver). Thirty-five ICU hospitalizations were analysed. Among these, 22 (63%) were secondary to a pneumothorax, 5 (14%) were associated with important cystic lesions without pneumothorax, and 8 (23%) included a diffuse micronodular lung infiltration in the context of multisystem disease. First-line vinblastine–corticosteroid combination therapy was administered to 16 patients; 12 patients required a second-line therapy (cladribine: n  = 7; etoposide-aracytine: n  = 3; targeted therapy n  = 2). A total of 6 children (35%) died (repeated pneumothorax: n  = 3; diffuse micronodular lung infiltration in the context of multisystem disease: n  = 2; following lung transplantation: n  = 1). For survivors, the median follow-up after ICU was 11.2 years. Among these, 9 patients remain asymptomatic despite abnormal chest imaging. Conclusions Severe lung involvement is unusual in childhood LCH, but it is associated with high mortality. Treatment guidelines should be improved for this group of patients: viral infection prophylaxis and early administration of a new LCH therapy, such as targeted therapy.
Validation of a high performance functional assay for individual radiosensitivity in pediatric oncology: a prospective cohort study (ARPEGE)
Background Approximately 900 children/adolescents are treated with radiotherapy (RT) every year in France. However, among the 80% of survivors, the cumulative incidence of long-term morbidity – including second malignancies - reach 73.4% thirty years after the cancer diagnosis. Identifying a priori the subjects at risk for RT sequelae is a major challenge of paediatric oncology. Individual radiosensitivity (IRS) of children/adolescents is unknown at this time, probably with large variability depending on the age when considering the changes in metabolic functions throughout growth. We previously retrospectively showed that unrepaired DNA double strand breaks (DSB) as well a delay in the nucleoshuttling of the pATM protein were common features to patients with RT toxicity. We aim to validate a high performance functional assay for IRS prospectively. Methods/design ARPEGE is a prospective open-label, non-randomized multicentre cohort study. We will prospectively recruit 222 children/adolescents who require RT as part of their routine care and follow them during 15 years. Prior RT we will collect blood and skin samples to raise a primary dermal fibroblast line to carry out in blind the IRS assay. As a primary objective, we will determine its discriminating ability to predict the occurrence of unusual early skin, mucous or hematological toxicity. The primary endpoint is the measurement of residual double-strand breaks 24 h after ex vivo radiation assessed with indirect immunofluorescence (γH2AX marker). Secondary endpoints include the determination of pATM foci at 10 min and 1 h (pATM marker) and micronuclei at 24 h. In parallel toxicity including second malignancies will be reported according to NCI-CTCAE v4.0 reference scale three months of the completion of RT then periodically during 15 years. Confusion factors such as irradiated volume, skin phototype, previous chemotherapy regimen, smoking, comorbities (diabetes, immunodeficiency, chronic inflammatory disease...) will be reported. Discussion ARPEGE would be the first study to document the distribution of IRS in the pediatric subpopulation. Screening hypersensitive patients would be a major step forward in the management of cancers, opening a way to personalized pediatric oncology. Trial registration ID-RCB number: 2015-A00975–44, ClinicalTrials.gov Identifier: NCT02827552 Registered 7/6/2016.
A biobank of pediatric patient-derived-xenograft models in cancer precision medicine trial MAPPYACTS for relapsed and refractory tumors
Pediatric patients with recurrent and refractory cancers are in most need for new treatments. This study developed patient-derived-xenograft (PDX) models within the European MAPPYACTS cancer precision medicine trial (NCT02613962). To date, 131 PDX models were established following heterotopical and/or orthotopical implantation in immunocompromised mice: 76 sarcomas, 25 other solid tumors, 12 central nervous system tumors, 15 acute leukemias, and 3 lymphomas. PDX establishment rate was 43%. Histology, whole exome and RNA sequencing revealed a high concordance with the primary patient’s tumor profile, human leukocyte-antigen characteristics and specific metabolic pathway signatures. A detailed patient molecular characterization, including specific mutations prioritized in the clinical molecular tumor boards are provided. Ninety models were shared with the IMI2 ITCC Pediatric Preclinical Proof-of-concept Platform (IMI2 ITCC-P4) for further exploitation. This PDX biobank of unique recurrent childhood cancers provides an essential support for basic and translational research and treatments development in advanced pediatric malignancies. A collection of 131 multi-panel pediatric tumor PDX models are generated and characterized in a comprehensive effort to provide support for basic and translational research and treatment development in advanced pediatric malignancies.
Deciphering Natural Killer Cell Cytotoxicity Against Medulloblastoma in vitro and in vivo: Implications for Immunotherapy
Medulloblastoma (MB) is the most prevalent paediatric brain tumour. Despite improvements in patient survival with current treatment strategies, the quality of life of these patients remains poor owing to the sequelae and relapse risk. An alternative, or, in addition to the current standard treatment, could be considered immunotherapy, such as Natural Killer cells (NK). NK cells are cytotoxic innate lymphoid cells that play a major role in cancer immunosurveillance. To date, the mechanism of cytotoxicity of NK cells, especially regarding the steps of adhesion, conjugation, cytotoxic granule polarisation in the cell contact area, perforin and granzyme release in two and three dimensions, and therapeutic efficacy in vivo have not been precisely described. Each step of NK cytotoxicity against the three MB cell lines was explored using confocal microscopy for conjugation, Elispot for degranulation, flow cytometry, and luminescence assays for target cell necrosis and lysis and mediators released by cytokine array, and then confirmed in a 3D spheroid model. Medulloblastoma-xenografted mice were treated with NK cells. Their persistence was evaluated by flow cytometry, and their efficacy in tumour growth and survival was determined. In addition, their effects on the tumour transcriptome were evaluated. NK cells showed variable affinities for conjugation with MB target cells depending on their subgroup and cytokine activation. Chemokines secreted during NK and MB cell co-culture are mainly associated with angiogenesis and immune cell recruitment. NK cell cytotoxicity induces MB cell death in both 2D and 3D co-culture models. NK cells initiated an inflammatory response in a human MB murine model by modulating the MB cell transcriptome. Our study confirmed that NK cells possess both in vitro and in vivo cytotoxic activity against MB cells and are of interest for the development of immunotherapy.
Educational outcomes in siblings of childhood leukemia survivors: Factors associated with school difficulties and comparison with general population
Background To investigate the educational outcomes of siblings of childhood leukemia survivors, explore determinants of school difficulties, and compare the rates of repeating grades between siblings and the general population. Methods A cross‐sectional study of childhood leukemia survivors' siblings recruited through the Leucémies de l'Enfant et de l'Adolescent cohort, a French long‐term follow‐up program, was conducted, and education‐related data were obtained via self‐report questionnaires. Adjusted logistic regression models were used to identify variables associated with school difficulties and time since diagnosis. Rates of repeating a grade in middle school were compared between siblings and the general population of the same generation. Results A total of 564 siblings with a mean time from diagnosis of 14.1 ± 6.4 years were included, among whom 139 (24.6%) repeated a grade, at an average of 6.4 ± 4.5 years after diagnosis. In multivariate analysis, the risk factors for repeating a grade were older siblings (odds ratio [OR] 2.3, p = 0.006), family financial difficulties (OR 2.8, p = 0.008), and history of repetition in survivors (OR, 2.5, p = 0.001). Sibling hematopoietic stem cell donors were at greater risk of repeating a grade long‐term after diagnosis (p = 0.018). Overall, siblings did not have a higher risk of educational delays at the end of middle school than the general population. Conclusion Although the results are reassuring, socioeconomic and cancer‐related factors may have an impact on siblings' schooling long after diagnosis. Paying attention to siblings contributes to identifying the most vulnerable families, allowing more attention and appropriate resources to avoid long‐term repercussions. Additionally, supportive and targeted interventions can be developed to improve the organization of education and the health care system.
Brothers and sisters of childhood acute leukemia survivors: Their long‐term quality of life and its determinants
Background Childhood cancer confront the whole family with a traumatic event. Because brothers and sisters may encounter emotional problems that can remain for a long time and that only few studies have assessed their long‐term outcome, our present objectives were to describe the long‐term quality of life (QoL) of childhood leukemia survivors' siblings and to explore its determinant. Methods Brothers and sisters (from 8‐year‐old) of survivors included in the French LEA Cohort completed a QoL questionnaire (according to their age). Scores were compared with those reported by age‐ and gender‐matched French general population and by survivors. Using a clustering method, siblings were categorized into 3 groups depending on their level of QoL's scores and factors likely to be linked with these clusters were explored with multivariate analyses. Results We included 689 brothers and sisters (313 minors, 376 adults) and the mean time from diagnosis was 13.2 ± 6.6 years. Minor siblings reported higher QoL scores than general population (p < 0.001), but a lower score for relationship with family than survivors (p < 0.001). In adult siblings, Mental Component Summary score was lower than general population (p < 0.001). Level of siblings' QoL was linked with female gender, but no association was found with cancer‐related factors. Conclusion Brothers and sisters expressed a divergent perception of their long‐term QoL depending on their age. To minimize the impact from childhood to adulthood, long‐term attention should also be paid to siblings, often referred as “forgotten children”. Years after diagnosis, brothers and sisters reported a different perception of their Quality of Life (QoL) according to their age, suggesting a deterioration in adulthood compared to their peers. Being female was associated with the lowest QoL level, but no association was found with cancer‐related factors.