Gene set enrichment analysis unveils the mechanism for the phosphodiesterase 4B control of glucocorticoid response in B-cell lymphoma

Clin Cancer Res. 2011 Nov 1;17(21):6723-32. doi: 10.1158/1078-0432.CCR-11-0770. Epub 2011 Jul 8.


Purpose: Resistance to glucocorticoid (GC) is a significant problem in the clinical management of lymphoid malignancies. Addressing this issue via a mechanistic understanding of relevant signaling pathways is more likely to yield positive outcomes.

Experimental design: We used gene set enrichment analysis (GSEA), multiple genetic models of gain and loss of function in B-cell lymphoma cell lines, in vitro and in vivo, and primary patient samples to characterize a novel relationship between the cyclic AMP/phosphodiesterase 4B (cAMP/PDE4B), AKT/mTOR activities, and GC responses.

Results: Starting from the GSEA, we found that overexpression of the PDE4B in diffuse large B-cell lymphoma (DLBCL) impinge on the same genes/pathways that are abnormally active in GC-resistant tumors. We used genetically modified cell lines to show that PDE4B modulates cAMP inhibitory activities toward the AKT/mTOR pathway and defines GC resistance in DLBCL. In agreement with these data, pharmacologic inhibition of PDE4 in a xenograft model of human lymphoma unleashed cAMP effects, inhibited AKT, and restored GC sensitivity. Finally, we used primary DLBCL samples to confirm the clinical relevance and biomarker potential of AKT/mTOR regulation by PDE4B.

Conclusions: Together, these data mechanistically elucidated how cAMP modulates GC responses in lymphocytes, defined AKT as the principal transducer of the growth inhibitory effects of cAMP in B cells, and allowed the formulation of genomics-guided clinical trials that test the ability of PDE4 inhibitors to restore GC sensitivity and improve the outcome of patients with B-cell malignancies.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Cell Line, Tumor
  • Cyclic AMP / metabolism
  • Cyclic Nucleotide Phosphodiesterases, Type 4 / biosynthesis
  • Cyclic Nucleotide Phosphodiesterases, Type 4 / genetics
  • Cyclic Nucleotide Phosphodiesterases, Type 4 / metabolism*
  • Dexamethasone / pharmacology
  • Drug Resistance, Neoplasm
  • Gene Expression Profiling
  • Glucocorticoids / pharmacology*
  • Humans
  • Lymphoma, Large B-Cell, Diffuse / drug therapy*
  • Lymphoma, Large B-Cell, Diffuse / enzymology
  • Lymphoma, Large B-Cell, Diffuse / genetics*
  • Mice
  • Mice, Inbred C57BL
  • Proto-Oncogene Proteins c-akt / metabolism
  • Signal Transduction
  • TOR Serine-Threonine Kinases / metabolism


  • Glucocorticoids
  • Dexamethasone
  • Cyclic AMP
  • MTOR protein, human
  • Proto-Oncogene Proteins c-akt
  • TOR Serine-Threonine Kinases
  • Cyclic Nucleotide Phosphodiesterases, Type 4
  • PDE4B protein, human