Efficacious proteasome/HDAC inhibitor combination therapy for primary effusion lymphoma

CD30 targeting with brentuximab vedotin: a novel therapeutic approach to primary effusion lymphoma

Primary effusion lymphoma (PEL) is an aggressive subtype of non-Hodgkin lymphoma characterized by short survival with current therapies, emphasizing the urgent need to develop new therapeutic approaches. Brentuximab vedotin (SGN-35) is an anti-CD30 monoclonal antibody (cAC10) conjugated by a protease-cleavable linker to a microtubule-disrupting agent, monomethyl auristatin E. Brentuximab vedotin is an effective treatment of relapsed CD30-expressing Classical Hodgkin and systemic anaplastic large cell lymphomas. Herein, we demonstrated that PEL cell lines and primary tumors express CD30 and thus may serve as potential targets for brentuximab vedotin therapy. In vitro treatment with brentuximab vedotin decreased cell proliferation, induced cell cycle arrest, and triggered apoptosis of PEL cell lines. Furthermore, in vivo brentuximab vedotin promoted tumor regression and prolonged survival of mice bearing previously reported UM-PEL-1 tumors as well as UM-PEL-3 tumors derived from a newly established and characterized Kaposi's sarcoma-associated herpesvirus- and Epstein-Barr virus-positive PEL cell line. Overall, our results demonstrate for the first time that brentuximab vedotin may serve as an effective therapy for PEL and provide strong preclinical indications for evaluation of brentuximab vedotin in clinical studies of PEL patients.

Human herpesvirus-8: Kaposi sarcoma, multicentric Castleman disease, and primary effusion lymphoma

Human herpesvirus 8 (HHV8) is a gamma herpesvirus associated with Kaposi sarcoma, multicentric Castleman disease, and primary effusion lymphoma, lymphoproliferative diseases that are most commonly observed in immunocompromised individuals. The viral genome expresses genes responsible for inhibition of apoptosis, cell cycle entry, and angiogenesis. Viral homologs of human regulatory genes are expressed, providing stimuli for angiogenesis, B-cell proliferation, and immune evasion. Variations in expression of these factors give rise to the 3 known HHV8-associated malignancies. Identification of these pathogenetic mechanisms has led to exploration of targeted treatment approaches for all 3 of these disorders with success in Kaposi sarcoma and multicentric Castleman disease; primary effusion lymphoma remains a clinical challenge.