The Leukemic Fly: Promises and Challenges.

Leukemia involves different types of blood cancers, which lead to significant mortality and morbidity. Murine models of leukemia have been instrumental in understanding the biology of the disease and identifying therapeutics. However, such models are time consuming and expensive in high throughput genetic and drug screening. Drosophilamelanogaster has emerged as an invaluable in vivo model for studying different diseases, including cancer. Fruit flies possess several hematopoietic processes and compartments that are in close resemblance to their mammalian counterparts. A number of studies succeeded in characterizing the fly's response upon the expression of human leukemogenic proteins in hematopoietic and non-hematopoietic tissues. Moreover, some of these studies showed that these models are amenable to genetic screening. However, none were reported to be tested for drug screening. In this review, we describe the Drosophila hematopoietic system, briefly focusing on leukemic diseases in which fruit flies have been used. We discuss myeloid and lymphoid leukemia fruit fly models and we further highlight their roles for future therapeutic screening. In conclusion, fruit fly leukemia models constitute an interesting area which could speed up the process of integrating new therapeutics when complemented with mammalian models.

Validation of a Drosophila model of wild-type and T315I mutated BCR-ABL1 in chronic myeloid leukemia: an effective platform for treatment screening.

Chronic myeloid leukemia is caused by a balanced chromosomal translocation resulting in the formation of BCR-ABL1 fusion gene encoding a constitutively active BCR-ABL1 tyrosine kinase, which activates multiple signal transduction pathways leading to malignant transformation. Standard treatment of chronic myeloid leukemia is based on tyrosine kinase inhibitors; however, some mutations have proven elusive particularly the T315I mutation. Drosophila melanogaster is an established in vivo model for human diseases including cancer. The targeted expression of chimeric human/fly and full human BCR-ABL1 in Drosophila eyes has been shown to result in detrimental effects. In this study, we expressed human BCR-ABL1p210 and the resistant BCR-ABL1p210/T315I fusion oncogenes in Drosophila eyes. Expression of BCR-ABL1p210/T315I resulted in a severe distortion of the ommatidial architecture of adult eyes with a more prominent rough eye phenotype compared to milder phenotypes in BCR-ABL1p210 reflecting a stronger oncogenic potential of the mutant. We then assessed the efficacy of the currently used tyrosine kinase inhibitors in BCR-ABL1p210 and BCR-ABL1p210/T315I expressing flies. Treatment of BCR-ABL1p210 expressing flies with potent kinase inhibitors (dasatinib and ponatinib) resulted in the rescue of ommatidial loss and the restoration of normal development. Taken together, we provide a chronic myeloid leukemia tailored BCR-ABL1p210 and BCR-ABL1p210/T315I fly model which can be used to test new compounds with improved therapeutic indices.