Abstract 1994: Smurf2 mediates ubiquitination and degradation of YY1 to suppress B-cell proliferation and lymphomagenesis.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Current treatment of diffuse large B-cell lymphoma (DLBCL), the most common type of non-Hodgkin's lymphoma, has improved patient survival significantly. However, 40-50% of DLBCL patients still die from this disease. There is a critical need to better understand the specific molecular pathways that are perturbed in DLBCL for the development of new and effective therapeutic approaches. We show that mice deficient in the E3 ubiquitin ligase Smurf2 spontaneously develop B-cell lymphomas that resemble human DLBCL with molecular features of germinal center B cells. We discover that Smurf2 mediates ubiquitination and degradation of YY1, a key germinal center transcription factor. Importantly, Smurf2 deficiency enhances YY1-mediated transactivation of c-Myc and B-cell proliferation. Furthermore, the expression of Smurf2 is significantly decreased in primary human DLBCL samples compared to normal B cells, and low levels of Smurf2 expression correlate with poor survival prognosis in DLBCL patients. The Smurf2-YY1-c-Myc regulatory axis represents a novel pathway perturbed in DLBCL that suppresses B-cell proliferation and lymphomagenesis, suggesting Smurf2 as a new therapeutic paradigm for DLBCL. Citation Format: Charusheila Ramkumar, Hang Cui, Yahui Kong, Stephen Jones, Rachel Gerstein, Hong Zhang. Smurf2 mediates ubiquitination and degradation of YY1 to suppress B-cell proliferation and lymphomagenesis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1994. doi:10.1158/1538-7445.AM2013-1994 Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.