Frequent mutations of FBXO11 identify BCL6 as a therapeutic target in Burkitt Lymphoma

ABSTRACT: BCL6 is a key oncogene in lymphoma pathogenesis. The expression of BCL6 in lymphoid cells can be deregulated by several mechanisms, including chromosomal translocations, somatic mutations in the promoter regulatory regions or reduced proteasome-mediated degradation. FBXO11 was recently identified as a major ubiquitin ligase involved in the degradation of BCL6 and is frequently inactivated in diffuse large B-cell lymphoma (DLBCL). In this work, we found that FBXO11 is frequently mutated in Burkitt lymphoma (BL) but rarely mutated in other BCL6-positive lymphomas, such as follicular lymphoma (FL). All mutations tested impaired FBXO11 mediated BCL6 degradation and FBXO11 knock-out completely stabilized BCL6 levels in human BL cell lines. Conditional deletion of one copy or both copies of FBXO11 in c-Myc-driven B cell lymphoma in mice accelerated lymphomagenesis, genetically confirming that FBXO11 is a haplo-insufficient oncosuppressor in lymphoma. In both FBOX11 WT and deficient BL mouse and human cell lines, blockade of BCL6 via a specific degrader or BCL6 inhibitors, impaired lymphoma growth in vitro and in vivo, an effect further enhanced by co-inhibition of c-Myc activity. Overall these findings not only establish FBXO11 as one of the most frequently mutated genes in BL, but also elucidate its biological functions in lymphomagenesis and thereby identify BCL6 as a specific therapeutic target in BL.

ORGANISM(S): Homo sapiens

PROVIDER: GSE159303 | GEO | 2021/12/31

REPOSITORIES: GEO