Recipient sex and donor leukemic cell characteristics determine leukemogenesis in patient-derived models.

In acute myeloid leukemia (AML), leukemogenesis depends on cell-intrinsic genetic aberrations and thus, studies on AML require investigations in an in vivo setting as provided by patient derived xenografts (PDX) models. Here we report that, next to leukemic cell characteristics, recipient sex highly influences the outgrowth of AML cells in PDX models, with females being much better repopulated than males in primary as well as secondary transplantation assays. Testosterone may be the more important player since, strikingly, better engraftment was seen in castrated versus control male recipients, while ovariectomy did not significantly impair engraftment in females.

Cut-like homeobox 1 (CUX1) tumor suppressor gene haploinsufficiency induces apoptosis evasion to sustain myeloid leukemia.

While oncogenes promote tumorigenesis, they also induce deleterious cellular stresses, such as apoptosis, that cancer cells must combat by coopting adaptive responses. Whether tumor suppressor gene haploinsufficiency leads to such phenomena and their mechanistic basis is unclear. Here, we demonstrate that elevated levels of the anti-apoptotic factor, CASP8 and FADD-like apoptosis regulator (CFLAR), promotes apoptosis evasion in acute myeloid leukemia (AML) cells haploinsufficient for the cut-like homeobox 1 (CUX1) transcription factor, whose loss is associated with dismal clinical prognosis.