Étude de la voie HOX-Flt3 dans les leucémies de type pré-B induites par E2A-Pbx1

Introduction: Notre laboratoire a précédemment établi que Hoxa9 accélérait l’apparition de leucémie de type B induite par E2A-PBX1. Une analyse par qRT-PCR a montré que les niveaux d’ARN de Flt3, une cible de Hoxa9, étaient 32 fois plus élevés dans les leucémies Hoxa9/E2A-PBX1 par rapport que dans les leucémies E2A-PBX1. Il est important de noter que l’expression aberrante de Flt3 est retrouvée dans les leucémies ALL de type B et les AML. De plus, l’activation constitutive de Flt3 est associée à un faible pronostic. Nous avons posé l’hypothèse que la maintenance/ré-initiation des leucémies de type pré-B induites par E2A-Pbx1 est associée à la présence du récepteur Flt3. Méthodes et Résultats: Premièrement, nous avons analysé par FACS la présence de Flt3 et mesuré l’expression de Flt3 par qRT-PCR des cellules E2A-PBX1 leucémiques pré-B. Nous avons montré que les cellules leucémiques E2A-PBX1 expriment l’ARNm du gène Flt3. Cependant, le récepteur n’était détectable à la surface cellulaire que dans des proportions variant de 0.3 à 28%. Deuxièmement, nous avons évalué le potentiel leucémique des fractions positive et négative pour Flt3. Toutes deux ont été capables de ré-initier la leucémie environ 20 jours après transplantation. Des analyses par FACS ont montré qu’une proportion de cellules leucémiques exprimaient Flt3, incluant même celles provenant de la fraction Flt3-. Troisièmement, une stratégie de perte de fonction de Flt3 par shARN a été mise en œuvre afin d’examiner le rôle de la voie de signalisation de Flt3 dans les cellules leucémiques E2A-PBX1. Pour ce faire, des cellules primaires leucémiques ont été infectées, soit par le shARN anti-Flt3 soit shARN contrôle, et transplantées dans des souris receveuses. Les cellules leucémiques contenant le shARN ont été capables de régénérer la leucémie. Cependant, une proportion des cellules exprimaient toujours Flt3, ce qui indique que l’efficacité des shARn n’était pas suffisante. Conclusion et Perspectives: Nos shARN ne sont pas suffisamment efficaces sur les cellules leucémiques choisies. De ce fait, nous proposons d’utiliser des cellules leucémiques moins agressives tout en réalisant le même set-up expérimental. Des transplantations dans des receveurs KO Flt3-/- seraient également requises afin de réellement étudier l’impact de la voie de signalisation Flt3 dans la ré-initiation leucémique.Introduction: Previous work in the laboratory have established that Hoxa9 accelerated the onset of E2A-PBX1 induced B cell leukaemia. qRT-PCR analysis showed that RNA levels of HOXA9 target Flt3 was 32-fold increased in Hoxa9/E2A-PBX1 compared to E2A-PBX1 leukaemia. It is important to note that aberrant expression of Flt3 is found in both B-ALL and AML. Moreover, constitutive activation of Flt3 is associated with a poor prognosis. We hypothesized that the acceleration of E2A-PBX1 B-ALL by Hoxa9 is caused through increased Flt3 signalling. Methods and Results: First, to evaluate whether Flt3 signalling is functionally relevant for E2A-PBX1 induced leukaemia, Flt3 expression was analysed by FACS and qRT-PCR. So far, we showed that E2A-PBX1 B-ALL express FLT3 but the receptor was detected on a variable proportion of the cells, ranging from 0.3-28 %. Secondly, we evaluated the leukemic potential of Flt3 positive and negative fractions. Both reinitiate leukaemia around 20 days post-transplantation. Thirdly, a shRNA mediated knockdown strategy for Flt3 has been applied to test the relevance of Flt3 signalling on E2A-PBX1 leukemic cells. To test this, primary leukaemic cells were infected, either with the shRNA anti-Flt3 or the shRNA control, and transplanted into recipient mice. Unexpectedly, no difference was observed between the two groups of mice. Conclusion and Relevance: Our shFLT3 is not efficient enough on the chosen leukemic cells. Therefore, we propose to apply the same set-up to a less aggressive leukaemia. Moreover, transplanting cells in Flt3-/- KO mice is required to really assess the impact of Flt3 signalling

Hoxa9 collaborates with E2A-PBX1 in mouse B cell leukemia in association with Flt3 activation and decrease of B cell gene expression

Background: The fusion protein E2A-PBX1 induces pediatric B cell leukemia in human. Previously, we reported oncogenic interactions between homeobox (Hox) genes and E2A-PBX1 in murine T cell leukemia. A proviral insertional mutagenesis screen with our E2A-PBX1 B cell leukemia mouse model identified Hoxa genes as potential collaborators to E2A-PBX1. Here we studied whether Hoxa9 could enhance E2A-PBX1 leukemogenesis. Results: We show that Hoxa9 confers a proliferative advantage to E2A-PBX1 B cells. Transplantation experiments with E2A-PBX1 transgenic B cells overexpressing Hoxa9 isolated from bone marrow chimeras showed that Hoxa9 accelerates the generation of E2A-PBX1 B cell leukemia, but Hoxa9 is unable to transform B cells alone. Quantitative-reverse transcriptase polymerase chain reaction analysis demonstrated a strong repression of B cell specific genes in these E2A-PBX1/Hoxa9 leukemias in addition to Flt3 activation, indicating inhibition of B cell differentiation in combination with enhanced proliferation. Overexpression of Hoxa9 in established E2A-PBX1 mouse leukemic B cells resulted in a growth advantage in vitro, which was also characterized by an enhanced expression of Flt3. Conclusions: we show for the first time that Hoxa9 collaborates with E2A-PBX1 in the oncogenic transformation of B cells in a mouse model that involves Flt3 signaling, which is potentially relevant to human disease

Harmonizing evidence-based practice, implementation context, and implementation strategies with user-centered design: a case example in young adult cancer care

BackgroundAttempting to implement evidence-based practices in contexts for which they are not well suited may compromise their fidelity and effectiveness or burden users (e.g., patients, providers, healthcare organizations) with elaborate strategies intended to force implementation. To improve the fit between evidence-based practices and contexts, implementation science experts have called for methods for adapting evidence-based practices and contexts and tailoring implementation strategies; yet, methods for considering the dynamic interplay among evidence-based practices, contexts, and implementation strategies remain lacking. We argue that harmonizing the three can be facilitated by user-centered design, an iterative and highly stakeholder-engaged set of principles and methods.MethodsThis paper presents a case example in which we used a three-phase user-centered design process to design and plan to implement a care coordination intervention for young adults with cancer. Specifically, we used usability testing to redesign and augment an existing patient-reported outcome measure that served as the basis for our intervention to optimize its usability and usefulness, ethnographic contextual inquiry to prepare the context (i.e., a comprehensive cancer center) to promote receptivity to implementation, and iterative prototyping workshops with a multidisciplinary design team to design the care coordination intervention and anticipate implementation strategies needed to enhance contextual fit.ResultsOur user-centered design process resulted in the Young Adult Needs Assessment and Service Bridge (NA-SB), including a patient-reported outcome measure and a collection of referral pathways that are triggered by the needs young adults report, as well as implementation guidance. By ensuring NA-SB directly responded to features of users and context, we designed NA-SB for implementation, potentially minimizing the strategies needed to address misalignment that may have otherwise existed. Furthermore, we designed NA-SB for scale-up; by engaging users from other cancer programs across the country to identify points of contextual variation which would require flexibility in delivery, we created a tool intended to accommodate diverse contexts.ConclusionsUser-centered design can help maximize usability and usefulness when designing evidence-based practices, preparing contexts, and informing implementation strategies-in effect, harmonizing evidence-based practices, contexts, and implementation strategies to promote implementation and effectiveness

User-centered design and the development of patient decision aids: protocol for a systematic review

Abstract Background Providing patient-centered care requires that patients partner in their personal health-care decisions to the full extent desired. Patient decision aids facilitate processes of shared decision-making between patients and their clinicians by presenting relevant scientific information in balanced, understandable ways, helping clarify patients’ goals, and guiding decision-making processes. Although international standards stipulate that patients and clinicians should be involved in decision aid development, little is known about how such involvement currently occurs, let alone best practices. This systematic review consisting of three interlinked subreviews seeks to describe current practices of user involvement in the development of patient decision aids, compare these to practices of user-centered design, and identify promising strategies. Methods/design A research team that includes patient and clinician representatives, decision aid developers, and systematic review method experts will guide this review according to the Cochrane Handbook and PRISMA reporting guidelines. A medical librarian will hand search key references and use a peer-reviewed search strategy to search MEDLINE, EMBASE, PubMed, Web of Science, the Cochrane Library, the ACM library, IEEE Xplore, and Google Scholar. We will identify articles across all languages and years describing the development or evaluation of a patient decision aid, or the application of user-centered design or human-centered design to tools intended for patient use. Two independent reviewers will assess article eligibility and extract data into a matrix using a structured pilot-tested form based on a conceptual framework of user-centered design. We will synthesize evidence to describe how research teams have included users in their development process and compare these practices to user-centered design methods. If data permit, we will develop a measure of the user-centeredness of development processes and identify practices that are likely to be optimal. Discussion This systematic review will provide evidence of current practices to inform approaches for involving patients and other stakeholders in the development of patient decision aids. We anticipate that the results will help move towards the establishment of best practices for the development of patient-centered tools and, in turn, help improve the experiences of people who face difficult health decisions. Systematic review registration PROSPERO CRD4201401324

Involving members of vulnerable populations in the development of patient decision aids: a mixed methods sequential explanatory study

Abstract Background Patient decision aids aim to present evidence relevant to a health decision in understandable ways to support patients through the process of making evidence-informed, values-congruent health decisions. It is recommended that, when developing these tools, teams involve people who may ultimately use them. However, there is little empirical evidence about how best to undertake this involvement, particularly for specific populations of users such as vulnerable populations. Methods To describe and compare the development practices of research teams that did and did not specifically involve members of vulnerable populations in the development of patient decision aids, we conducted a secondary analysis of data from a systematic review about the development processes of patient decision aids. Then, to further explain our quantitative results, we conducted semi-structured telephone interviews with 10 teams: 6 that had specifically involved members of vulnerable populations and 4 that had not. Two independent analysts thematically coded transcribed interviews. Results Out of a total of 187 decision aid development projects, 30 (16%) specifically involved members of vulnerable populations. The specific involvement of members of vulnerable populations in the development process was associated with conducting informal needs assessment activities (73% vs. 40%, OR 2.96, 95% CI 1.18–7.99, P = .02) and recruiting participants through community-based organizations (40% vs. 11%, OR 3.48, 95% CI 1.23–9.83, P = .02). In interviews, all developers highlighted the importance, value and challenges of involving potential users. Interviews with developers whose projects had involved members of vulnerable populations suggested that informal needs assessment activities served to center the decision aid around users’ needs, to better avoid stigma, and to ensure that the topic truly matters to the community. Partnering with community-based organizations may facilitate relationships of trust and may also provide a non-threatening and accessible location for research activities. Conclusions There are a small number of key differences in the development processes for patient decision aids in which members of vulnerable populations were or were not specifically involved. Some of these practices may require additional time or resources. To address health inequities, researchers, communities and funders may need to increase awareness of these approaches and plan accordingly

Additional file 1: Appendix 1. of Involving members of vulnerable populations in the development of patient decision aids: a mixed methods sequential explanatory study

Interview guide. Appendix 2. Included projects. Appendix 3. Variables considered. (DOCX 390 kb