Disruption of Aneuploidy and Senescence Induced by Aurora Inhibition Promotes Intrinsic Apoptosis in Double Hit or Double Expressor Diffuse Large B-cell Lymphomas

Double hit (DH) or double expressor (DE) diffuse large B-cell lymphomas (DLBCL) are aggressive non-Hodgkin's lymphomas (NHL) with translocations and/or overexpressions of MYC and BCL-2, which are difficult to treat. Aurora kinase (AK) inhibition with alisertib in DH/DE-DLBCL induces cell death in ∼30%, while ∼70% are aneuploid and senescent cells (AASC), a mitotic escape mechanism contributing to drug resistance. These AASCs elaborated a high metabolic rate by increased AKT/mTOR and ERK/MAPK activity via BTK signaling through the chronic active B-cell receptor (BCR) pathway. Combinations of alisertib + ibrutinib or alisertib + ibrutinib + rituximab significantly reduced AASCs with enhanced intrinsic cell death. Inhibition of AK + BTK reduced phosphorylation of AKT/mTOR and ERK-1/2, upregulated phospho-H2A-X and Chk-2 (DNA damage), reduced Bcl-6, and decreased Bcl-2 and Bcl-xL and induced apoptosis by PARP cleavage. In a DE-DLBCL SCID mouse xenograft model, ibrutinib alone was inactive, while alisertib + ibrutinib was additive with a tumor growth inhibition (TGI) rate of ∼25%. However, TGI for ibrutinib + rituximab was ∼50% to 60%. In contrast, triple therapy showed a TGI rate of >90%. Kaplan-Meier survival analysis showed that 67% of mice were alive at day 89 with triple therapy versus 20% with ibrutinib + rituximab. All treatments were well tolerated with no changes in body weights. A novel triple therapy consisting of alisertib + ibrutinib + rituximab inhibits AASCs induced by AK inhibition in DH/DE-DLBCL leading to a significant antiproliferative signal, enhanced intrinsic apoptosis and may be of therapeutic potential in these lymphomas. Mol Cancer Ther; 16(10); 2083-93. ©2017 AACR.12 month embargo; published online: 14 June 2017This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu