A proliferation-inducing ligand mediates follicular lymphoma B-cell proliferation and cyclin D1 expression through phosphatidylinositol 3-kinase-regulated mammalian target of rapamycin activation

Mamta Gupta, Stacey R. Dillon, Steven C. Ziesmer, Andrew L Feldman, Thomas Elmer Witzig, Stephen Maxted Ansell, James R Cerhan, Anne J Novak

Research output: Contribution to journalArticle

40 Scopus citations


A proliferation-inducing ligand (APRIL), as well as its receptors transmembrane activator and calcium-modulating cyclophilin ligand (CAML) interactor (TACI) and B-cell maturation antigen (BCMA), has been shown to be important in B-cell biology, and overexpression of APRIL in mice results in development of lymphoma. Limited data are available on APRIL-specific signaling responses, but knockout models suggest that signaling through TACI is critical to B-cell homeostasis. To better understand the mechanism by which APRIL exerts its effects and how it may contribute to lymphomagenesis, we sought to characterize the outcome of APRIL-TACI interactions. In support of murine studies, we find that APRIL induces proliferation of human patient follicular lymphoma (FL) B cells in a TACI-dependent manner. This study also shows that APRIL is expressed within the tumor microenvironment and that, upon engagement with TACI, APRIL mediates activation of the phosphatidylinositol 3-kinase (PI3K) pathway. Activation of PI3K via APRIL results in phosphorylation of Akt and mammalian target of rapamycin (mTOR) and the mTOR-specific substrates p70S6 kinase and 4E-binding protein 1 in a TACI-dependent manner. APRIL-mediated signaling also results in phosphorylation of Rb and upregulation of cyclin D1. These studies are the first to characterize APRIL-TACI - specific signaling and suggest a role for this ligand-receptor pair in FL B-cell growth.

Original languageEnglish (US)
Pages (from-to)5206-5216
Number of pages11
Issue number21
StatePublished - 2009


ASJC Scopus subject areas

  • Hematology
  • Biochemistry
  • Cell Biology
  • Immunology

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