Engraftment characterization of risk-stratified AML in NSGS mice

Abstract

Acute myeloid leukemia (AML) is the commonest acute leukemia in adults. Disease heterogeneity is well-documented and patient stratification determines treatment decisions. Patient-derived xenografts (PDXs) of risk-stratified AMLs are crucial for studying AML biology and testing novel therapeutics. Despite recent advances in PDX modeling of AML, reproducible engraftment of human AML is mainly limited to high-risk (HR) cases, with inconsistent or very protracted engraftment observed for favorable-risk (FR) and intermediate-risk (IR) patients. We have characterized the engraftment robustness/kinetics in NSGS mice of 28 AML patients grouped according to molecular/cytogenetic classification, and have assessed whether the orthotopic co-administration of patient-matched bone marrow mesenchymal stromal cells (BM-MSCs) improves AML engraftment. PDX event-free survival correlated well with the predictable prognosis of risk-stratified AML patients. The majority (85%-94%) of the mice were engrafted in BM independently of the risk group, although HR-AML patients showed engraftment levels significantly superior to those of FR- and IR-AML patients. Importantly, the engraftment levels observed in NSGS mice by week 6 remained stable overtime. Serial transplantation and long-term culture-initiating cell (LTC-IC) assays revealed long-term engraftment limited to HR-AML patients, fitter leukemia-initiating cells (LICs) in HR- than in FR- or IR-AML samples, and the presence of AML-LICs in the CD34- leukemic fraction, regardless the risk group. Finally, orthotopic co-administration of patient-matched BM-MSCs with AML cells resulted dispensable for BM engraftment levels but favored peripheralization of engrafted AML cells. This comprehensive characterization of human AML engraftment in NSGS mice offers a valuable platform for in vivo testing of targeted therapies in risk-stratified AML patient samples.

Epigenetic mechanisms controlling human leukemia stem cells and therapy resistance

“…Overall engraftment efficiency was 46 and 70% in primary and secondary transplants, respectively (Extended Data Table 1). Consistent with prior observations 12,13 , serial engraftment and transplantation were higher for specimens obtained from patients with chemotherapy resistance, as compared to those who achieved remission upon standard-of-care chemotherapy treatment (80 versus 60%; Extended Data Table 1).…”

A comprehensive single-cell expression atlas of human AML leukemia-initiating cells unravels the contribution of HIF pathway and its therapeutic potential

“…Two-color FISH experiments were performed using either XL CBFB, XL t(8;21) (both from MetaSystems) or LSI MLL Break-Apart (Abbott Molecular) probes to detect inv(16), t(8;21) or MLL rearrangements, respectively. FISH was performed following standard procedures (90, 92, 93). Briefly, cells were denatured at 73°C in 70% formamide in 2×SSC for 2 min.…”

“…The Animal Care Committee of the Barcelona Biomedical Research Park approved all experimental procedures with mice (HRH-17-0014 and HRH-19-0003). A total of 0.3-1 × 10 6 primary AML cells were intra-BM transplanted into sublethally irradiated (2 Gy) NSG mice (90). AML cells were previously incubated 30 min at 4ºC with OKT3 (BioXCell).…”

The Multi-Kinase Inhibitor EC-70124 Is a Promising Candidate for the Treatment of FLT3-ITD-Positive Acute Myeloid Leukemia

“…The captured and amplified DNA was sequenced using NextSeq550 platform (Illumina ® ). The results were analyzed using DataGenomics platform as described elsewhere [37][38][39].…”