Recruitment of BCL6 to target genes in Philadelphia chromosome positive acute lymphoblastic leukemia. Homo sapiens

The Philadelphia chromosome (Ph) encodes the oncogenic BCR-ABL1 tyrosine kinase, which defines a subset of acute lymphoblastic leukemia (ALL) with a particularly unfavorable prognosis. Tyrosine kinase inhibitors (TKI) are widely used to treat patients with leukemia driven by BCR-ABL1 and other oncogenic tyrosine kinases. In response to TKI-treatment, BCR-ABL1 ALL cells upregulate BCL6 protein levels by ~90-fold, i.e. to similar levels as in diffuse large B cell lymphoma (DLBCL) with BCL6 translocations. In this study, we used genome tiling arrays to identify BCL6 target genes with specific recruitment of BCL6. Overall design: Three Ph+ ALL cell lines (BV-173, NALM-1 and TOM-1) in duplicate were either treated with 10µM STI571 (Imatinib) for 24 hours or cultured in absence of STI571.