A defect of the INK4-Cdk4 checkpoint and c-myc collaborate in blastoid mantle cell lymphoma (MCL)-like lymphoma formation in mice

Mantle cell lymphoma (MCL) is a B cell malignancy characterized by a monoclonal proliferation of lymphocytes with co-expression of CD5, CD43 but not CD23. Typical MCL are associated with cyclin D1 overexpression, and blastoid MCL variants are associated with c-myc translocations. We have developed a murine model of MCL-like lymphoma by crossing Cdk4R24C mice with c-myc-3’RR transgenic mice. Cdk4R24C mice is a knock-in strain that express a Cdk4 protein resistant to inhibition by p16INK4a and other INK4 family members. Breeding Cdk4R24C mice with c-myc-3’RR transgenic mice prone to develop aggressive Burkitt lymphoma-like lymphoma leads in c-myc/Cdk4R24C mice to development of clonal blastoid MCL-like lymphoma. A defect of the INK4-Cdk4 checkpoint can participate to lymphomagenesis in conjunction with additional alterations of cell cycle control, a situation which might be reminiscent of the development of human blastoid MCL. B splenocytes from 4 c-myc/Cdk4(R24C) lymphoma mice and 4 wt mice were investigated.