Synergistic activity of BET protein antagonist-based combinations in Mantle Cell Lymphoma cells sensitive or resistant to ibrutinib

ABSTRACT: To determine the global transcriptome changes in mantle cell lymphoma cells following treatment with the BET bromodomain antagonist, JQ1 Mantle Cell Lymphoma (MCL) cells exhibit increased B cell receptor and NFkB activities. The BET protein BRD4 is essential for the transcriptional activity of NFkB. Here, we demonstrate that treatment with the BET protein bromodomain antagonist (BA) JQ1 attenuates MYC and CDK4/6, inhibits the nuclear RelA levels and the expression of NFκB target genes including Bruton’s Tyrosine Kinase (BTK) in MCL cells. While lowering the levels of the anti-apoptotic BCL2 family proteins, BA treatment induces the pro-apoptotic protein BIM and exerts dose-dependent lethality against cultured and primary MCL cells. Co-treatment with BA and the BTK inhibitor ibrutinib synergistically induces apoptosis of MCL cells. Compared to each agent alone, co-treatment with BA and ibrutinib markedly improved the median survival of mice engrafted with the MCL cells. BA treatment also induced apoptosis of the in vitro isolated, ibrutinib-resistant MCL cells which overexpress CDK6, BCL2, Bcl-xL, XIAP and AKT, but lack ibrutinib resistance-conferring BTK mutation. Co-treatment with BA and panobinostat (pan-histone deacetylase inhibitor) or palbociclib (CDK4/6 inhibitor) or ABT-199 (BCL2 antagonist) synergistically induced apoptosis of the ibrutinib-resistant MCL cells. These findings highlight and support further in vivo evaluation of the efficacy of the BA-based combinations with these agents against MCL, including ibrutinib-resistant MCL. MO2058 cells treated with vehicle, 250 nM or 1000 nM JQ1 for 8 hours. Samples were acquired and analyzed in duplicate.

ORGANISM(S): Homo sapiens

SUBMITTER: Kapil Bhalla 

PROVIDER: E-GEOD-70651 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress