Hoxa9/meis1-transgenic zebrafish develops acute myeloid leukemia-like disease with rapid onset and high-penetrance

HOXA9/MEIS1 plays a synergistic causative role and overexpresses frequently in acute myeloid leukemia (AML). Hoxa9/Meis1 transgenic murine results in rapid leukemic transformation of primary bone marrow cells. However, murine model is not suitable to perform a high-throughput phenotypic screen in vivo and identify compounds for AML therapy. A transgenic zebrafish overexpresses hoxa9/meis1 need to generate. We have engineered an inducible transgenic line Tg (drl:hoxa9;hsp70:meis1) harboring hoxa9/meis1 under the draculin (drl) promoter. The downregulation of runx1, c-myb, mpx, mfap4, and gata1 in Tg (drl:hoxa9;hsp70:meis1) embryos indicated enforced hoxa9/meis1 perturbs embryonic hematopoiesis. Importantly, adult Tg (drl:hoxa9;hsp70:meis1) develops malignant myeloid disease with an abundance of myeloid precursor cells, anemia, and high mortality after a latency period (~5-months-aged) with comparable to murine model and human AML patients. Genome-wide transcription changes analysis indicated arrested differentiation genes such as gata2b, notch1b, and gfi1ab are upregulated. Leflunomide, inhibitor of enzyme dihydroorotate dehydrogenase (DHODH) which is a potential option for differentiation therapy of AML, relieves defective hematopoiesis in transgenic embryos and larvae. Collectively, we have identified an inducible malignant myeloid disease transgenic zebrafish model similar to AML and provided a unique opportunity for high-throughput in vivo chemical screening for AML therapy and study the related mechanisms. Overall design: To evaluate genome wide gene expression changes, the blood cells from kidneys were harvested from adult WT(AB strain) or Tg (drl:hoxa9;hsp70:meis1) zebrafish (~5-months-aged). The blood cells from three kidneys were mixed into one sample and lysed by Trizol.