RESUMO
Acute leukemia is a heterogeneous set of diseases affecting children and adults. Current prognostic factors are not accurate predictors of the clinical outcome of adult patients and the stratification of risk groups remains insufficient. For that reason, this study proposes a multifactorial analysis which integrates clinical parameters, ex vivo tumor characterization and behavioral in vivo analysis in zebrafish. This model represents a new approach to understand leukemic primary cells behavior and features associated with aggressiveness and metastatic potential. Xenotransplantation of primary samples from patients newly diagnosed with acute leukemia in zebrafish embryos at 48 hpf was used to asses survival rate, dissemination pattern, and metastatic potential. Seven samples from young adults classified in adverse, favorable or intermediate risk group were characterized. Tumor heterogeneity defined by Leukemic stem cell (LSC) proportion, was performed by metabolic and cell membrane biomarkers characterization. Thus, our work combines all these parameters with a robust quantification strategy that provides important information about leukemia biology, their relationship with specific niches and the existent inter and intra-tumor heterogeneity in acute leukemia. In regard to prognostic factors, leukemic stem cell proportion and Patient-derived xenografts (PDX) migration into zebrafish were the variables with highest weights for the prediction analysis. Higher ALDH activity, less differentiated cells and a broader and random migration pattern are related with worse clinical outcome after induction chemotherapy. This model also recapitulates multiple aspects of human acute leukemia and therefore is a promising tool to be employed not only for preclinical studies but also supposes a new tool with a higher resolution compared to traditional methods for an accurate stratification of patients into worse or favorable clinical outcome.
RESUMO
Resumen El pez cebra es un modelo establecido para el estudio del desarrollo en vertebrados y es especialmente útil para la investigación del proceso de hematopoyesis y las enfermedades asociadas a esta. Los linajes principales, los genes y los procesos de desarrollo con los seres humanos son conservados. En los últimos años, el pez cebra se ha utilizado cada vez más como un modelo para estudiar enfermedades hematopoyéticas humanas, incluyendo la leucemia linfoblástica aguda. Esta revisión evidencia la importancia del estudio de esta enfermedad en Colombia debido a las diferencias de la etiología que presenta este tipo de leucemia en comparación con otros países. Además, describe la aplicación del pez cebra como una herramienta alternativa para investigaciones preclínicas de la leucemia linfoblástica aguda. Este modelo es asequible, facilita la experimentación, su manipulación es relativamente simple y tiene gran versatilidad para estudios moleculares y genéticos del cáncer y está disponible en Colombia.
Abstract The zebrafish is an established model for the study of vertebrate development, and it is specially useful for the research into haematopoiesis and diseases associated with this process. Major lineages, genes, and developmental processes are conserved between zebrafish and humans. Thus it has been increasingly used as a model for a number of haematopoietic human diseases, such as acute lymphoblastic leukaemia. This review highlights the importance of the study of this disease in Colombia, because of the differences in its aetiology compared to other countries. It also describes the application of the zebrafish as an alternative tool for pre-clinical research of acute lymphoblastic leukaemia. This model is affordable, facilitates experimentation and handling, and is extremely versatile for molecular and genetic studies into cancer, and it is now available in Colombia.