p66Shc deficiency enhances CXCR4 and CCR7 recycling in CLL B cells by facilitating their dephosphorylation-dependent release from β-arrestin at early endosomes

Oncogene. 2018 Mar;37(11):1534-1550. doi: 10.1038/s41388-017-0066-2. Epub 2018 Jan 12.

Abstract

Neoplastic cell traffic abnormalities are central to the pathogenesis of chronic lymphocytic leukemia (CLL). Enhanced CXC chemokine receptor-4 (CXCR4) and chemokine receptor-7 (CCR7) recycling contributes to the elevated surface levels of these receptors on CLL cells. Here we have addressed the role of p66Shc, a member of the Shc family of protein adaptors the expression of which is defective in CLL cells, in CXCR4/CCR7 recycling. p66Shc reconstitution in CLL cells reduced CXCR4/CCR7 recycling, lowering their surface levels and attenuating B-cell chemotaxis, due to their accumulation in Rab5+ endosomes as serine-phosphoproteins bound to β-arrestin. This results from the ability of p66Shc to inhibit Ca2+ and PP2B-dependent CXCR4/CCR7 dephosphorylation and β-arrestin release. We also show that ibrutinib, a Btk inhibitor that promotes leukemic cell mobilization from lymphoid organs, reverses the CXCR4/CCR7 recycling abnormalities in CLL cells by increasing p66Shc expression. These results, identifying p66Shc as a regulator of CXCR4/CCR7 recycling in B cells, underscore the relevance of its deficiency to CLL pathogenesis and provide new clues to the mechanisms underlying the therapeutic effects of ibrutinib.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenine / analogs & derivatives
  • Adult
  • Animals
  • Case-Control Studies
  • Cells, Cultured
  • Endosomes / drug effects
  • Endosomes / metabolism*
  • Endosomes / pathology
  • Germ-Line Mutation
  • Humans
  • Leukemia, Lymphocytic, Chronic, B-Cell* / drug therapy
  • Leukemia, Lymphocytic, Chronic, B-Cell* / genetics
  • Leukemia, Lymphocytic, Chronic, B-Cell* / metabolism
  • Leukemia, Lymphocytic, Chronic, B-Cell* / pathology
  • Mice
  • Mice, Knockout
  • Phosphorylation / genetics
  • Piperidines
  • Proteolysis
  • Pyrazoles / therapeutic use
  • Pyrimidines / therapeutic use
  • Receptors, CCR7 / metabolism*
  • Receptors, CXCR4 / metabolism*
  • Src Homology 2 Domain-Containing, Transforming Protein 1 / genetics*
  • beta-Arrestins / metabolism*

Substances

  • CCR7 protein, human
  • CXCR4 protein, human
  • Piperidines
  • Pyrazoles
  • Pyrimidines
  • Receptors, CCR7
  • Receptors, CXCR4
  • SHC1 protein, human
  • Src Homology 2 Domain-Containing, Transforming Protein 1
  • beta-Arrestins
  • ibrutinib
  • Adenine