The synergistic effect of BCR signaling inhibitors combined with an HDAC inhibitor on cell death in a mantle cell lymphoma cell line

Apoptosis. 2015 Jul;20(7):975-85. doi: 10.1007/s10495-015-1125-1.

Abstract

Mantle cell lymphoma (MCL) is a B cell malignancy characterized by aberrant expression of cyclin D1 due to a t(11;14) translocation. MCL is refractory to conventional chemotherapy, and treatment remains challenging. We investigated the efficacy of the histone deacetylase (HDAC) inhibitor vorinostat combined with one of several B-cell receptor (BCR) signaling inhibitors on MCL cell death and the underlying mechanisms, using MCL cell lines. The Bruton's tyrosine kinase inhibitor PCI-32765 and the spleen tyrosine kinase inhibitor R406 showed synergistic effects with vorinostat on growth inhibition. Treatment with PCI-32765 or R406 alone induced 27.3 ± 2.1 or 25.1 ± 3.2% apoptosis. When combined with vorinostat, these apoptotic fractions significantly increased to 50.8 ± 4.9 and 63.1 ± 5.0%, respectively. Activation of caspase-3 and poly-(ADP-ribose) polymerase cleavage were markedly increased. We performed gene expression profiling following treatment with the combination of vorinostat and individual BCR signaling inhibitors using a microarray, and differentially expressed genes were identified. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis showed that the nuclear factor (NF)-κB signaling pathway was significantly enriched following treatment with the combination of vorinostat and R406. Protein expression analysis confirmed the down-regulation of NF-κB1/p105 and cyclin D1, suggesting inhibition of the NF-κB pathway. Taken together, the combination of an HDAC inhibitor and a BCR signaling inhibitor may be a novel therapeutic strategy for MCL.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenine / analogs & derivatives
  • Apoptosis / drug effects*
  • Caspases / metabolism
  • Cell Line, Tumor
  • Cyclin D1 / metabolism
  • Drug Synergism
  • Histone Deacetylase Inhibitors / pharmacology*
  • Humans
  • Hydroxamic Acids / pharmacology*
  • Lymphoma, Mantle-Cell / pathology*
  • NF-kappa B / metabolism
  • Oxazines / pharmacology
  • Piperidines
  • Protein Kinase Inhibitors / pharmacology*
  • Pyrazoles / pharmacology
  • Pyridines / pharmacology
  • Pyrimidines / pharmacology
  • Receptors, Antigen, B-Cell / antagonists & inhibitors
  • Receptors, Antigen, B-Cell / metabolism*
  • Vorinostat

Substances

  • Histone Deacetylase Inhibitors
  • Hydroxamic Acids
  • N4-(2,2-dimethyl-3-oxo-4H-pyrid(1,4)oxazin-6-yl)-5-fluoro-N2-(3,4,5-trimethoxyphenyl)-2,4-pyrimidinediamine
  • NF-kappa B
  • Oxazines
  • Piperidines
  • Protein Kinase Inhibitors
  • Pyrazoles
  • Pyridines
  • Pyrimidines
  • Receptors, Antigen, B-Cell
  • Cyclin D1
  • ibrutinib
  • Vorinostat
  • Caspases
  • Adenine