title: Humanized bone marrow mouse model as a preclinical tool to assess therapy-mediated hematotoxicity.
abstract: OBJECTIVE
  Preclinical in vivo studies can help guide the selection of agents and regimens for clinical testing. However, one of the challenges in screening anticancer therapies is the assessment of off-target human toxicity. There is a need for in vivo models that can simulate efficacy and toxicities of promising therapeutic regimens. For example, hematopoietic cells of human origin are particularly sensitive to a variety of chemotherapeutic regimens, but in vivo models to assess potential toxicities have not been developed. In this study, a xenograft model containing humanized bone marrow is utilized as an in vivo assay to monitor hematotoxicity.
  
  
  METHODS
  A proof-of-concept, temozolomide-based regimen was developed that inhibits tumor xenograft growth. This regimen was selected for testing because it has been previously shown to cause myelosuppression in mice and humans. The dose-intensive regimen was administered to NOD.Cg-Prkdc(scid)IL2rg(tm1Wjl)/Sz (NOD/SCID/γchain(null)), reconstituted with human hematopoietic cells, and the impact of treatment on human hematopoiesis was evaluated.
  
  
  RESULTS
  The dose-intensive regimen resulted in significant decreases in growth of human glioblastoma xenografts. When this regimen was administered to mice containing humanized bone marrow, flow cytometric analyses indicated that the human bone marrow cells were significantly more sensitive to treatment than the murine bone marrow cells and that the regimen was highly toxic to human-derived hematopoietic cells of all lineages (progenitor, lymphoid, and myeloid).
  
  
  CONCLUSIONS
  The humanized bone marrow xenograft model described has the potential to be used as a platform for monitoring the impact of anticancer therapies on human hematopoiesis and could lead to subsequent refinement of therapies prior to clinical evaluation.
authors.affiliation: Herman B Wells Center for Pediatric Research, Department of Pediatrics, Section of Pediatric Hematology/Oncology, The Riley Hospital for Children, Indianapolis, Indiana 46202, USA.
authors.forename: Shanbao
authors.initials: S
authors.lastname: Cai
authors.forename: Haiyan
authors.initials: H
authors.lastname: Wang
authors.forename: Barbara
authors.initials: B
authors.lastname: Bailey
authors.forename: Aaron
authors.initials: A
authors.lastname: Ernstberger
authors.forename: Beth E
authors.initials: BE
authors.lastname: Juliar
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Sinn
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Chan
authors.forename: David R
authors.initials: DR
authors.lastname: Jones
authors.forename: Lindsey D
authors.initials: LD
authors.lastname: Mayo
authors.forename: Arthur R
authors.initials: AR
authors.lastname: Baluyut
authors.forename: W Scott
authors.initials: WS
authors.lastname: Goebel
authors.forename: Karen E
authors.initials: KE
authors.lastname: Pollok
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects / Q000627:therapeutic use*; D001853:Bone Marrow / Q000187:drug effects*; D001854:Bone Marrow Cells / Q000187:drug effects; D045744:Cell Line, Tumor; D036101:Cord Blood Stem Cell Transplantation; D003606:Dacarbazine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives; D004305:Dose-Response Relationship, Drug; D005260:Female; D005909:Glioblastoma / Q000188:drug therapy* / Q000473:pathology; D006147:Guanine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D016688:Mice, Inbred NOD; D018345:Mice, Knockout; D016513:Mice, SCID; D016019:Survival Analysis; D000077204:Temozolomide; D018183:Transplantation Chimera / Q000097:blood; D016896:Treatment Outcome; D047368:Tumor Burden / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
chemical_list: C064976:O(6)-benzylguanine; D006147:Guanine; D003606:Dacarbazine; D000077204:Temozolomide