The Nek2 Genetic Knockout Mouse Model Provides Novel Treatment Strategies in Myeloma and Lymphoma

Abstract

Background; Major progress in the treatment of B cell tumors has been made in the past decades. Nevertheless, relapses and refractoriness to currently available chemotherapy and even to high dose therapy with stem cell transplantation still cause significant mortality. NEK2, NEver in Mitosis Gene A (NIMA)-Related Kinase 2, is a serine/threonine kinase. High expression of NEK2 increases cell survival and drug resistance, resulting in poor clinical outcome in multiple cancers including multiple myeloma and lymphoma. In this study, we used genetic mouse models to evaluate whether NEK2 is a druggable target in the treatment of B cell tumors including myeloma and diffuse large B-cell lymphoma (DLBCL).Materials and Methods: We have generated Nek2 knockout mice and crossed these with Eµ-Myc mice. RNA-sequencing was performed to determine signaling pathways related to Nek2 inhibition. Both NEK2 and USP7 (a protein interacting with NEK2) inhibitors were applied to treat myeloma and DLBCL in vitro and in vivo.Results: Mouse studies showed that Nek2 played a critical role in B cell tumor development and progression. Specifically, in genetic Eμ-MYC transgenic mice, which spontaneously develop DLBCL and Burkitt lymphoma, knockout of Nek2 prevented B cell tumor development and significantly extended mouse survival. Further, immunohistochemistry analyses showed that Nek2 was highly detected in biopsies from aggressive Burkitt lymphoma patients. Our data also indicate that both NEK2 and USP7 inhibitors significantly inhibited myeloma cell and lymphoma cell growth in vitro and in vivo models and without apparent toxicity to normal tissues. Intriguingly, the combination of USP7 inhibitor P5091 with doxorubicin blocked B cell lymphoma development and extended lymphoma mouse survival.Conclusions: Our studies demonstrate the importance of Nek2 function in tumorigenesis and progression in B cell lineage malignancies. Both NEK2 and USP7 inhibitors showed excellent efficacy in the treatment of myeloma and B-cell lymphoma. DisclosuresNo relevant conflicts of interest to declare.