CARD11 mutation and HBZ expression induce lymphoproliferative disease and adult T-cell leukemia/lymphoma

The oncogenic ability of mutant CARD11 (E626K), one of most frequently mutated genes in adult T-cell leukemia and its cooperative effect with HBZ expression, using the CD4 promoter-driven HBZ transgenic mouse model, is investigated. Adult T-cell leukemia/lymphoma (ATL) is caused by human T-cell leukemia virus type 1 (HTLV-1). In addition to HTLV-1 bZIP factor (HBZ), a leukemogenic antisense transcript of HTLV-1, abnormalities of genes involved in TCR-NF-kappa B signaling, such as CARD11, are detected in about 90% of patients. Utilizing mice expressing CD4(+) T cell-specific CARD11(E626K) and/or CD4(+) T cell-specific HBZ, namely CARD11(E626K)(CD4-Cre) mice, HBZ transgenic (Tg) mice, and CARD11(E626K)(CD4-Cre);HBZ Tg double transgenic mice, we clarify these genes' pathogenetic effects. CARD11(E626K)(CD4-Cre) and HBZ Tg mice exhibit lymphocytic invasion to many organs, including the lungs, and double transgenic mice develop lymphoproliferative disease and increase CD4(+) T cells in vivo. CARD11(E626K) and HBZ cooperatively activate the non-canonical NF-kappa B pathway, IRF4 targets, BATF3/IRF4/HBZ transcriptional network, MYC targets, and E2F targets. Most KEGG and HALLMARK gene sets enriched in acute-type ATL are also enriched in double transgenic mice, indicating that these genes cooperatively contribute to ATL development.

Automated summary

The study investigates the oncogenic ability of mutant CARD11 (E626K), one of the most frequently mutated genes in adult T-cell leukemia, and its cooperative effect with HBZ expression. Using a mouse model, the researchers clarify the pathogenetic effects of these genes and find that they cooperatively activate multiple signaling pathways, promoting the development of ATL.