CBFA2T3-GLIS2 oncogenic fusion is sufficient for leukemic transformation

Purpose: To investigate whether human cord blood CD34+ hematopoietic stem and progenitor cells (CB HSPCs) transduced with CBFA2T3-GLIS2 (C/G) expression construct recapitulates primary C/G acute myeloid leukemia (AML). Methods: CB HSPCs were transduced with either C/G fusion/GFP or GFP control contruct (C/G-CB or GFP-CB cells, respectively) and cultured in endothelial cell (EC) co-culture or myeloid promoting culture (MC) for 12 weeks. RNA from transduced cells were isolated at week 1, 6 and 12 in either culture condition. Whole transcriptome RNA-sequencing was conducted using 75bp strand-specific paired-end mRNA libraries and sequenced on the Illumina HiSeq 2000/2500. Results: Unsurpervised clustering analysis of RNA-sequencing of C/G-CB cells cultured with ECs or in MC demonstrated that the C/G-CB cells from weeks 6 and 12 in EC co-culture clustered with primary C/G-positive patient samples, but not C/G-CB cells cultured in MC nor GFP controls. In addition, EC C/G-CB cells had signficant enrichemnt of WNT, HEDGEHOG and TGF-beta pathways. However, both EC and MC cultures revealed up-regulation of ERG and BMP2, genes compared to GFP control, which are genes previously shown to be strongly upregulated in C/G AML, and concomitant down-regulation of the erythroid-megakaryocyte differentiation gene GATA1. Conclusions: We find that lentiviral transduction of C/G fusion is sufficient to induce malignant transformation of human CB HSPCs that recapitulates the transcriptome of primary C/G AML. Overall design: CB HSPCs engineered to express C/G fusion transcript were cultured with an endothelial co-culture system or in myeloid promoting conditions for 1, 6, and 12 weeks and underwent transcriptome profiling using ribodepleted (rRNA depleted) RNA-sequencing.