XPO1 amplification abrogates the effects of E571K XPO1 mutation in B-cell lymphoma

ABSTRACT: XPO1 gene encodes exportin 1 (XPO1) that controls the nuclear export of cargo proteins and RNAs. Almost 25% of primary mediastinal B-cell lymphomas (PMBL) and classical Hodgkin lymphomas (cHL) cases harboured a recurrent XPO1 point mutation (NM_003400, chr2:g61718472C>T) resulting in the E571K modification within the hydrophobic groove of the protein, the site of cargo proteins binding. We investigated the functional impact of XPO1E571K mutation using cell lines having various XPO1 status. We first confirmed that the mutation was present both within the XPO1 mRNA and the corresponding protein. In the U2940 cell line having a wild-type (wt) XPO1 gene, we introduced the E571K mutation using several CRISPR-Cas9 strategies. Using a barcoding method to trace the mutation, we observed that the mutation gave no advantage in vitro. Indeed, the effects of XPO1E571K mutation were hidden by the presence of the XPO1 wt allele. Strikingly, XPO1E571K mutation never occurred as homozygous or hemizygous in our patients��������� cohort. We further showed that XPO1E571K mutation modified selinexor binding to XPO1 and in turn, its sensitivity to this drug. We concluded that the balance between the wild-type and the mutated allele of XPO1 is a key element in defining XPO1 functions and oncogenic properties.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): B Cell, Blood

DISEASE(S): Lymphoma

SUBMITTER: François GUILLONNEAU  

LAB HEAD: Brigitte Sola

PROVIDER: PXD016916 | Pride | 2020-10-01

REPOSITORIES: Pride