The c-myc proto-oncogene is activated by translocation in Burkitt's lymphoma and substitutions in codon 58 stabilize the Myc protein or augment its oncogenic potential. In wild-type Myc, phosphorylation of Ser 62 and Thr 58 provide a landing pad for the peptidyl prolyl-isomerase Pin1, which in turn promotes Ser 62 dephosphorylation and Myc degradation. However, the role of Pin1 in Myc-induced lymphomagenesis remains unknown. We show here that genetic ablation of Pin1 reduces lymphomagenesis in E-myc transgenic mice. In both Pin1-deficient B-cells and MEFs, the proliferative response to Myc was selectively impaired, with no alterations in Myc-induced apoptosis or mitogen-induced cell cycle entry. This proliferative defect wasn't attributable to alterations in either Ser 62 phosphorylation or Myc-regulated transcription, but to the indirect activation of an Arf-p53 dependent cytostatic response. Pin1 silencing in lymphomas retarded disease progression in mice, making Pin1 an attractive therapeutic target in Myc-driven tumors. SOURCE: Marco,J.,Morelli (Marco.Morelli@iit.it) -  Istituto Italiano di Tecnologia

Pluto Bioinformatics

GSE77482: Pin1 is required for sustained B cell proliferation upon oncogenic activation of Myc