MLL-rearranged acute lymphoblastic leukaemia stem cell interactions with bone marrow stroma promote survival and therapeutic resistance that can be overcome with CXCR4 antagonism

Edward Allan R Sison, Rachel E. Rau, Emily Mcintyre, Li Li, Donald Small, Patrick A Brown

Research output: Contribution to journalArticle


Infants with MLL-rearranged (MLL-R) acute lymphoblastic leukaemia (ALL) have a dismal prognosis. While most patients achieve remission, approximately half of patients recur with a short latency to relapse. This suggests that chemotherapy-resistant leukaemia stem cells (LSCs) survive and can recapitulate the leukaemia. We hypothesized that interactions between LSCs and the bone marrow microenvironment mediate survival and chemotherapy resistance in MLL-R ALL. Using primary samples of infant MLL-R ALL, we studied the influence of bone marrow stroma on apoptosis, proliferation, and cytotoxicity induced by the FLT3 inhibitor lestaurtinib. MLL-R ALL were differentially protected by stroma from spontaneous apoptosis compared to non-MLL-R ALL. Co-culture of bulk MLL-R ALL in direct contact with stroma or with stroma-produced soluble factors promoted proliferation and cell cycle entry. Stroma also protected bulk MLL-R ALL cells and MLL-R ALL LSCs from lestaurtinib-mediated cytotoxicity. Previous studies have demonstrated that CXCR4 mediates bone marrow microenvironment signalling. Using a xenograft model of MLL-R ALL, we demonstrated that CXCR4 inhibition with AMD3100 (plerixafor) led to markedly enhanced efficacy of lestaurtinib. Therefore, the bone marrow microenvironment is a mediator of chemotherapy resistance in MLL-R ALL and targeting leukaemia-stroma interactions with CXCR4 inhibitors may prove useful in this high-risk subtype of paediatric ALL.

Original languageEnglish (US)
Pages (from-to)785-797
Number of pages13
JournalBritish Journal of Haematology
Issue number6
Publication statusPublished - Mar 2013



  • Acute lymphoblastic leukaemia
  • CXCR4
  • Microenvironment
  • Mixed lineage leukaemia
  • Stroma

ASJC Scopus subject areas

  • Hematology

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