Oncogenic JAK2V617F causes PD-L1 expression, mediating immune escape in myeloproliferative neoplasms

Sci Transl Med. 2018 Feb 21;10(429):eaam7729. doi: 10.1126/scitranslmed.aam7729.

Abstract

Recent evidence has revealed that oncogenic mutations may confer immune escape. A better understanding of how an oncogenic mutation affects immunosuppressive programmed death ligand 1 (PD-L1) expression may help in developing new therapeutic strategies. We show that oncogenic JAK2 (Janus kinase 2) activity caused STAT3 (signal transducer and activator of transcription 3) and STAT5 phosphorylation, which enhanced PD-L1 promoter activity and PD-L1 protein expression in JAK2V617F-mutant cells, whereas blockade of JAK2 reduced PD-L1 expression in myeloid JAK2V617F-mutant cells. PD-L1 expression was higher on primary cells isolated from patients with JAK2V617F-myeloproliferative neoplasms (MPNs) compared to healthy individuals and declined upon JAK2 inhibition. JAK2V617F mutational burden, pSTAT3, and PD-L1 expression were highest in primary MPN patient-derived monocytes, megakaryocytes, and platelets. PD-1 (programmed death receptor 1) inhibition prolonged survival in human MPN xenograft and primary murine MPN models. This effect was dependent on T cells. Mechanistically, PD-L1 surface expression in JAK2V617F-mutant cells affected metabolism and cell cycle progression of T cells. In summary, we report that in MPN, constitutive JAK2/STAT3/STAT5 activation, mainly in monocytes, megakaryocytes, and platelets, caused PD-L1-mediated immune escape by reducing T cell activation, metabolic activity, and cell cycle progression. The susceptibility of JAK2V617F-mutant MPN to PD-1 targeting paves the way for immunomodulatory approaches relying on PD-1 inhibition.

Publication types

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

MeSH terms

  • Animals
  • B7-H1 Antigen / genetics
  • B7-H1 Antigen / metabolism*
  • Cell Proliferation / genetics
  • Cell Proliferation / physiology
  • Cell Transformation, Neoplastic
  • Hematologic Neoplasms / genetics
  • Hematologic Neoplasms / metabolism*
  • Humans
  • Janus Kinase 2 / genetics
  • Janus Kinase 2 / metabolism*
  • K562 Cells
  • Mice
  • Myeloproliferative Disorders / genetics
  • Myeloproliferative Disorders / metabolism*
  • Signal Transduction / genetics
  • Signal Transduction / physiology
  • Tumor Cells, Cultured

Substances

  • B7-H1 Antigen
  • Janus Kinase 2