Systems medicine dissection of chromosome 1q amplification reveals a novel PBX1-FOXM1 axis for targeted therapy in multiple myeloma

Here we report the use of high-throughput sequencing technologies (RNA-seq, ChIP-seq) to identify the molecular programme of PBX1 and FOXM1 in multiple myeloma cells (MM1S, U266 cell lines). We performed Chromatin Immunoprecipitation followed by sequencing (ChIP-seq) against PBX1 in MM1S and U266 cells (n=2). In addition, we identifed the transcriptome of PBX1-depleted and FOXM1-depleted myeloma cells 3 days after transduction with shRNA-expressing lentiviral vectors. Molecular characterization revealed PBX1 as a novel epigenetic regulator of myeloma cell survival and proliferation. PBX1 directly and unilaterally controls the FOXM1 transcriptional programme and, together,they regulate the high-risk transcriptional signature of chr1q-amplified cells. Pharmacological inhibition of the unified PBX1-FOXM1 axis with thiostrepton showed selectivity against chr1q-amplified MM. Altogether, these data reveal PBX1-FOXM1 axis as a novel therapeutic avenue against chr1q-amplified MM. Identification of the transcriptional and epigenomic programmes of PBX1 and FOXM1 in MM1S and U266 multiple myeloma cells using ChIP-seq and RNA-seq.