Cooperative role of distinctive TP53 and PTEN combined loss in the peripheral T cell lymphoma-GATA3 molecular subgroup.

Peripheral T cell lymphoma (PTCL) is a heterogeneous group of postthymic T cell neoplasms, with ~40% classified as PTCL-not otherwise specified (PTCL-NOS). PTCL-GATA3, a molecularly defined subtype, associated with T helper 2 (TH2)-like differentiation and poor prognosis, has frequent co-occurrence of TP53 loss/mutation and heterozygous PTEN loss. CD4+ T cell conditional mouse models with Trp53 mutation/deletion and Pten loss demonstrated mature T cell lymphomas (mTCLs) with TH2-like transcriptomic and immunophenotypic profiles. Molecular studies revealed that codeletion of Trp53/Pten induced T cell receptor and Janus kinase-signal transducer and activator of transcription signaling, promoting TH2 differentiation while inhibiting TH1 differentiation. These findings were validated by CRISPR editing of TP53/PTEN loss in human CD4+ T cells and mechanistically evaluated the p53 binding region in intron-3 of GATA3, resulting in transcriptional repression. Transcriptomic profiles of m-TCLs recapitulated human-PTCL-GATA3 transcriptome and distinguished PTCL-NOS subtypes. Preclinical assessment of m-TCLs with PI3Kγ/δ inhibitors significantly improved survival, supporting a therapeutic approach for the p53-aberrant PTCL-GATA3.