GSE126486
Genome-wide CRISPR-Cas9 screen identifies druggable synthetic lethality between LSD1 and MTORC1 in MLL-translocated AML
Lysine Specific Demethylase 1 (LSD1 or KDM1A) is one of a number of epigenetic regulators which have recently emerged as candidate therapeutic targets in acute myeloid leukaemia (AML). Pharmacological inhibitors of LSD1 such as the tranylcypromine derivatives have already commenced evaluation in early phase clinical trials; however like all acute leukaemia therapies, it is unlikely that these inhibitors are effective as single agents. Therefore, there is a strong rationale to identify proteins that collaborate with LSD1 to maintain the leukemic phenotype and could be targeted in combination with LSD1 for enhanced therapeutic benefit. Using a genome-wide CRISPR-Cas9 dropout screen in human THP1 cells, we identified multiple regulatory components of the amino acid sensing arm of mTORC1 signalling - RRAGA, MLST8, and LAMTOR2 – as synthetic lethalities with LSD1 inhibition. Genetic and/or pharmacologic inhibition of selected genes in combination with LSD1 inhibition showed significant anti-leukemic activity by inducing a more extensive and wide-ranging myeloid differentiation program and reducing cell proliferation in THP1 and primary human AML cells in vitro and in vivo. In conclusion, we report that inhibition of mTORC1 sensitizes human MLL-translocated AML cells to LSD1 inhibitor-mediated differentiation therefore highlighting a novel combination approach for evaluation in clinical trials. Overall design: Transcriptional profiles were generated by deep sequencing using Illumina NextSeq 500. CRISPR screen samples were generated using Illumina HiSeq 2500.