Abstract 700: Characterization of new AML PDX models: Engraftment kinetics and mutational profile

Abstract

Acute myeloid leukemia (AML) is a genetically heterogeneous cancer of progenitor cells in myeloid hematopoiesis. Due to heterogeneity, most of AMLs are not responsive to targeted therapy. In addition, treatment outcome varies greatly depending upon patient age, disease etiology and mutational status. Previously, a large repository of well-characterized patient-derived- xenografts (PDXs) of hematologic malignancies was established (Townsend et al., 2016). This repository was generated by injecting primary bone marrow and blood samples from patients with leukemia into NSG (NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ) mice. An average success rate of 23.2% engraftment was observed in first passage (P0). In this study, we have characterized ten AML PDX models in NSG-SGM3 mice by serial transplantation. NSG-SGM3 (NOD.Cg-Prkdcscid Il2rgtm1Wjl Tg(CMV-IL3,CSF2,KITLG)1Eav/MloySzJ) mice have been found to have increased proliferation and survival of engrafted AML cells along with decreased disease latency (Wunderlich et al., 2010). Leukemic engraftment in these models was confirmed by flow analysis for hCD45+ hCD33+ in the peripheral blood, bone marrow and spleen of engrafted mice. Kinetics of engraftment varied from one model to another; and ranged from 10% - 80% of hCD33+ in peripheral blood 8 week post AML cell injection (1X106 cells/mouse). Four models displayed positive response to Cytarabine (Ara-C) treatment with reduction in levels of human CD33+ cells following a 5-day treatment cycle. Data will be presented on model characterization to show distinct engraftment kinetics, correlation with disease mutations and response to AML standard of care drug Cytarabine. These models have varying mutational profiles and treatment histories. Mutations include FLT3, FLT3-ITD, NPM1, TP53, DNMT3A and CUX1 alone or in combination. Treatment phases at the time of collection varied from untreated to relapse post-chemotherapy. These AML PDX models are useful tools for testing new experimental therapeutics. Diversity of these AML PDX models will facilitate focus on specific AML targets, thus providing an invaluable tool set to support drug discovery. Citation Format: Pali Kaur, Victoria Sachs, Amanda L. Christie, David M. Weinstock, James G. Keck. Characterization of new AML PDX models: Engraftment kinetics and mutational profile [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 700.