DEK and WT1 Affect Alternative Splicing of Genes Involved in Hematopoietic Cell Lineage and Resistance to Chemotherapy in Acute Myeloid Leukemia Cells.

Abstract 2392 In humans, the majority of all protein-coding transcripts contain introns that are removed by mRNA splicing carried out by spliceosomes. Mutations in the spliceosome machinery have recently been identified using whole-exome/genome technologies in myelodysplastic syndromes (MDS) and in acute myeloid leukemia (AML). In MDS the frequency of somatic spliceosomal mutations (SSM) range from 1–3% for U2AF1 in RARS/RCMD-RS to more than 70% for SF3B1 in ARSI. These values are significantly lower in AML whereas AML cells cumulate numerous splicing defects. Beside SSMs, one can propose that alternative splicing (AS) might be disturbed by other processes such as abnormal protein-protein interactions. DEK and WT1 are 2 oncogenes overexpressed in most patients with AML. They physiologically influence AS through physical interactions with the heterodimer U2AF1/U2AF2 involved in the recognition of splice acceptor site by the splicing machinery. It is therefore possible that the leukemogenic overexpression of DEK or WT1 might deregulate AS in AML cells, even in the absence of SSM. Here we show that DEK and WT1 affect AS in AML cells. Exon expression profiling was performed in triplicate with MOLM13, KASUMI and KG1 AML cells stably knocked down or not for DEK and WT1 through shRNA. The efficiency of shRNA-mediated silencing was confirmed by western blot and total RNA was analyzed using the Exon microarray platform GeneChip Human Exon 1.0 ST (Affymetrix). Microarray data were cross-compared between cell lines and only statistically significant modifications (p Disclosures: No relevant conflicts of interest to declare.