Paediatric bone marrow mesenchymal stem cells support acute myeloid leukaemia cell survival and enhance chemoresistance via contact‐independent mechanism

Children diagnosed with acute myeloid leukaemia (paediatric AML [pAML]) have limited treatment options and relapse rates due to chemoresistance and refractory disease are over 30%. Current treatment is cytotoxic and in itself has long-lasting harsh side effects. New, less toxic treatments are needed. The bone marrow microenvironment provides chemoprotection to leukaemic cells through cell communication and interaction with mesenchymal stem cells (MSCs), but this is not well defined in pAML. Using primary patient material, we identify a cell contact-independent mechanism of MSC-mediated chemoprotection involving extrinsic soluble factors that is abrogated through inhibition of the JAK/STAT and ERK pathways.