Abstract LB-277: Induction chemotherapy induces enrichment of leukemic stem cells in PDX models of acute myeloid leukemia

Human leukemic stem cells may be one of the leading causes for resistance or treatment failure in acute myeloid leukemia patients. To gain insights into the mechanisms underlying chemo-resistance of AML disease, we evaluated the biomarkers and the pharmacological properties of minimal residual disease post induction therapy. The PDX models were established by iv injecting acute myeloid leukemia patient cells in NOD/SCID/Il2rg(-/-) mice (NSG). The disease progression was tracked by the AML counts in peripheral blood and bone marrow via FACS analysis. In the PDX models, daunorubicin/cytarabine (DA) chemotherapy showed early antileukemic efficacy through apoptosis induction and antiproliferation. However, treatment showed minimal survival benefits and all treated leukemic mice relapsed due to the minimal residual disease (MRD). FACS analysis showed that DA therapy induced enrichment of CD34+ and CLL1+/CD117- cells in the MRD of the BM0407 and BM2407 AML PDX models, respectively. Subsequently, we performed self-renewal functional test by in vivo reimplantation of sorted CD34+ and CLL1+/CD117- cells. The limiting delusion analysis showed that the chemo- resistant CD34+ and CLL1+/CD117- cells are much more tumorigenic than their counterpart CD34- and CLL1+/CD117+ cells, respectively. This work provides insights into the mechanism of chemo-resistance and helps identifying new strategies to improve AML therapy. Citation Format: Cathy C. Zhang, Zhengming Yan, Bernadette Pascual, Stephen Huang, Qing Zong, Mark Elliot, Patrick Lappin. Induction chemotherapy induces enrichment of leukemic stem cells in PDX models of acute myeloid leukemia. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-277.