Project description:We performed a RNA-seq analysis of an ibrutinib-sensitive mantle cell lymphoma cell line treated with ibrutinib for up to 4 d to study transcriptomic adaptations to the BTK inhibitor in surviving cells.
Project description:Altered features of tumor cells acquired across therapy can result in the survival of treatment-resistant clones that may cause minimal residual disease (MRD). Despite the efficacy of ibrutinib in treating relapsed/refractory mantle cell lymphoma, the obstacle of residual cells contributes to relapses of this mature B-cell neoplasm, and the disease remains incurable. RNA-seq analysis of an ibrutinib-sensitive mantle cell lymphoma cell line following ibrutinib incubation of up to 4 d, corroborated our previously postulated resistance mechanism of a metabolic switch to reliance on oxidative phosphorylation (OXPHOS) in surviving cells. Besides, we had shown that treatment-persisting cells were characterized by increased CD52 expression. Therefore, we hypothesized that combining ibrutinib with another agent targeting these potential escape mechanisms could minimize the risk of survival of ibrutinib-resistant cells. Concomitant use of ibrutinib with OXPHOS-inhibitor IACS-010759 increased toxicity compared to ibrutinib alone. Targeting CD52 was even more efficient, as addition of CD52 mAb in combination with human serum following ibrutinib pretreatment led to rapid complement-dependent-cytotoxicity in an ibrutinib-sensitive cell line. In primary mantle cell lymphoma cells, a higher toxic effect with CD52 mAb was obtained, when cells were pretreated with ibrutinib, but only in an ibrutinib-sensitive cohort. Given the challenge of treating multi-resistant mantle cell lymphoma patients, this work highlights the potential use of anti-CD52 therapy as consolidation after ibrutinib treatment in patients who responded to the BTK inhibitor to achieve MRD negativity and prolong progression-free survival.
Project description:The use of Bruton tyrosine kinase (BTK) inhibitors such as ibrutinib has achieved a remarkable clinical response in mantle cell lymphoma (MCL). Acquired drug resistance, however, is significant and impacts long-term survival of MCL patients. Here we demonstrate that DNMT3A is involved in ibrutinib resistance. We found that DNMT3A expression is upregulated upon ibrutinib treatment in ibrutinib-resistant MCL cells. Genetic and pharmacological analyses revealed that DNMT3A mediates ibrutinib resistance independent of its DNA-methylation function. Mechanistically, DNMT3A induces the expression of MYC target genes through interaction with the transcription factors MEF2B and MYC, thus mediating metabolic reprogramming to oxidative phosphorylation (OXPHOS). Targeting DNMT3A by a low dose of decitabine inhibits the growth of ibrutinib-resistant lymphoma cells both in vitro and in a patient-derived xenograft mouse model. These findings suggest that targeting DNMT3A-medited metabolic reprogramming to OXPHOS with decitabine provides a potential therapeutic strategy to overcome ibrutinib resistance in relapsed/refractory MCL.
Project description:Ibrutinib, a bruton's tyrosine kinase inhibitor, was shown to have high response rates in mantle cell lymphoma (MCL), an aggressive B-cell lymphoma. However, emergence of ibrutinib resistance (IR) and subsequent fatal progression is of significant clinical concern. By implementing genomics, chemical proteomics and drug screening, we report that enhancer remodeling-mediated transcriptional activation and adaptive signaling changes drive the malignant phenotype of IR. Accordingly, IR MCL cells are vulnerable to inhibition of the transcriptional machinery and especially to inhibition of cyclin-dependent kinase 9 (CDK9). Thus, targeting transcriptional activation offers a novel strategy to prevent the emergence of IR and overcome IR via impeding IR-associated cellular signaling reprogramming in MCL. In addition, our ex-vivo microfluidic image-based functional drug screen can function not only as new technology platforms for predicting clinical therapeutic response but also, in conjunction with genomic profiling in primary MCL samples, identify the molecular vulnerabilities for drug resistance evolution, providing insight into the underlying IR mechanisms for MCL and other B-cell malignancies
Project description: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 Brutonâs 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.
Project description:Ibrutinib, a bruton's tyrosine kinase inhibitor, was shown to have high response rates in mantle cell lymphoma (MCL), an aggressive B-cell lymphoma. However, emergence of ibrutinib resistance (IR) and subsequent fatal progression is of significant clinical concern. By implementing genomics, chemical proteomics and drug screening, we report that enhancer remodeling-mediated transcriptional activation and adaptive signaling changes drive the malignant phenotype of IR. Accordingly, IR MCL cells are vulnerable to inhibition of the transcriptional machinery and especially to inhibition of cyclin-dependent kinase 9 (CDK9). Thus, targeting transcriptional activation offers a novel strategy to prevent the emergence of IR and overcome IR via impeding IR-associated cellular signaling reprogramming in MCL. In addition, our ex-vivo microfluidic image-based functional drug screen can function not only as new technology platforms for predicting clinical therapeutic response but also, in conjunction with genomic profiling in primary MCL samples, identify the molecular vulnerabilities for drug resistance evolution, providing insight into the underlying IR mechanisms for MCL and other B-cell malignancies