The nonobese diabetic/severe combined immunodeficient (NOD/SCID) mouse model of childhood acute lymphoblastic leukemia reveals intrinsic differences in biologic characteristics at diagnosis and relapse

Abstract

Acute lymphoblastic leukemia cells from 19 children, including 7 who remain in first complete remission (CR1), were engrafted into nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. High-level infiltration of bone marrow, spleen, and liver was observed, with variable infiltration of other organs. The immunophenotypes of xenografts were essentially unaltered compared with the original patient sample. In addition, sequencing of the entire p53 coding region revealed no mutations in 14 of 14 xenografts (10 from patients at diagnosis and 4 at relapse). Cells harvested from the spleens of engrafted mice readily transferred the leukemia to secondary and tertiary recipients. To correlate biologic characteristics of xenografts with clinical and prognostic features of the patients, the rates at which individual leukemia samples engrafted in NOD/SCID mice were analyzed. Differences in biologic correlates were encountered depending on stage of disease: a direct correlation was observed between the rate of engraftment and length of CR1 for samples harvested at relapse (r ‫؍‬ 0.96; P ‫؍‬ .002), but not diagnosis (r ‫؍‬ 0.38; P ‫؍‬ .40). In contrast, the in vivo responses of 6 xenografts to vincristine showed a direct correlation (r ‫؍‬ 0.96; P ‫؍‬ .002) between the length of CR1 and the rate at which the leukemia cell population recovered following vincristine treatment, regardless of whether the xenografts were derived from patients at diagnosis or relapse. This study supports previous findings that the NOD/SCID model of childhood ALL provides an accurate representation of the human disease and indicates that it may be of value to predict relapse and design alternative treatment strategies in a patient-specific manner. (Blood. 2002;99: 4100-4108)

p53-independent Epigenetic Repression of the p21WAF1 Gene in T-cell Acute Lymphoblastic Leukemia

“…The protocol for harvesting and storage of the specimens is detailed in previous work (34). Bone marrow mononuclear cells were isolated by density gradient centrifugation using Lymphoprep (Axis-Shield, Oslo, Norway).…”

p21WAF1 modulates drug-induced apoptosis and cell cycle arrest in B-cell precursor acute lymphoblastic leukemia

“…Protocols for processing samples, harvesting, cryopreservation and establishing PDX cells are detailed in previous work. 57 In vitro cytotoxicity assays In vitro drug sensitivity was assessed using the colorimetric methyl-thiazolyl-tetrazolium (MTT) assay, and is described elsewhere. 56 The cells were exposed to etoposide (Sigma-Aldrich, #E1383), vorinostat (donation from Merck Research Laboratories), terameprocol (donation from Erimos Pharmaceuticals) or an equivalent volume of dimethyl sulfoxide (DMSO) vehicle (Sigma-Aldrich).…”

Induction of Vascular Endothelial Growth Factor Secretion by Childhood Acute Lymphoblastic Leukemia Cells via the FLT-3 Signaling Pathway

“…The panel of ALL xenograft cells used in this study is representative of the heterogeneity of this disease in terms of ALL subtype and clinical outcome of the patients from whom they were derived (13). The 2 xenografts that secreted the largest amounts of VEGF also exhibited the highest cell surface FLT-3 expression (ALL-3 and P-14).…”

“…To explore the possible relationship between FLT-3 and VEGF, we assessed cell surface FLT-3 and FLinduced VEGF expression in a series of ex vivo cultured pediatric ALL xenograft lines (13,14). In addition, the myelomonocytic leukemia cell line, MV4;11, which has a constitutively active FLT-3 with an internal tandem duplication (ITD), was also used (16).…”

“…Childhood ALL xenograft cells were cultured, harvested, and characterized as previously described (13,14). For all experiments, xenograft cells were retrieved from cryostorage and resuspended at a density of 2 Â 10 6 cells/mL in QBSF-60 medium (Quality Biological, Inc.), supplemented with penicillin (100 U/mL), streptomycin (100 mg/mL), and L-glutamine (2 mmol/L; PSG).…”