Long-range oncogenic enhancers play an important role in cancer. Yet, it remains unclear whether similar regulation of tumor suppressor genes is relevant. In this context, loss of expression of the tumor suppressor PTEN is associated with the pathogenesis of various cancers, including T-cell acute lymphoblastic leukemia (T-ALL). Here, we demonstrate that PTEN is regulated in T-cells by a distal enhancer (PE), which is targeted by recurrent focal deletions in T-ALL. This highly conserved regulatory element interacts with and transactivates the PTEN promoter. Consistently, PE deletion in T-ALL cells leads to reduced PTEN levels and proliferative advantage. Moreover, PE-null mice show reduced PTEN levels in the thymus and develop NOTCH1-induced T-ALL with faster kinetics. Furthermore, secondary loss of PE in established leukemias leads to accelerated progression and a gene expression signature driven by Pten loss. Altogether, our results identify PE as the first long-range tumor suppressor enhancer directly implicated in cancer.
This 4C-seq analysis of the PTEN locus uses human (DND41, HPBALL and JURKAT) and mouse (N1dE_PKM2 and HDdPEST) cells. In each case 4C-seq was done with a bait on the promoter and putative enhancer loci.