The Notch/Hes1 pathway sustains NF-M-NM-:B activation through CYLD repression in T cell leukemia

ABSTRACT: The NF-M-NM-:B pathway is a critical regulator of the immune system and has been implicated in cellular transformation and tumorigenesis. NF-M-NM-:B response is regulated by the activation state of the IM-NM-:B kinase (IKK) complex and triggered by a wide spectrum of stimuli. We previously reported that NF-M-NM-:B is downstream of Notch1 in T cell acute lymphoblastic leukaemia (T-ALL), however both the mechanisms involving Notch1-induced NF-M-NM-:B activation and the potential importance of NF-M-NM-:B in the maintenance of the disease are unknown. Here we visualize Notch-induced NF-M-NM-:B activation using both human T-ALL cell lines and animal models of this type of leukemia. We show that it is not Notch1 itself but Hes1, a canonical Notch target, the responsible for sustaining IKK activation in T-ALL. Hes1 exerts its effects by a direct transcriptional repression of the deubiquitinating enzyme CYLD, a well-characterized IKK inhibitor. Consistently, CYLD expression is significantly reduced in primary T-ALL leukemias. Finally, we demonstrate that IKK complex inhibition is a promising option for the targeted therapy of T-ALL as suppression of IKK function affected both the survival of human T-ALL cells in vitro and the maintenance of the disease in vivo. Transcriptional consequences of NF-kB inactivation in human T-ALL1 cell line Twenty samples were analyzed: human T-ALL, CEM, KOPT-K, DND41, HPB-ALL cells lines have been treated at 100uM for 16 hours with control peptide or IKKM-NM-3 Nemo binding domain (NBD) inhibitory peptide, that specifically block the canonical NF-M-NM-:B activity by disrupting the interaction of IKKM-NM-3 to IKKM-NM-2 and IKKM-NM-1

ORGANISM(S): Homo sapiens

SUBMITTER: Iannis Aifantis 

PROVIDER: E-GEOD-20667 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress