TGFβ1-mediated SMAD3 enhances PD-1 expression on antigen-specific T cells in cancer

Benjamin V. Park, Zachary T. Freeman, Ali Ghasemzadeh, Michael A. Chattergoon, Alleluiah Rutebemberwa, Jordana Steigner, Matthew E. Winter, Thanh V. Huynh, Suzanne M. Sebald, Se Jin Lee, Fan Pan, Drew M. Pardoll, Andrea L. Cox

Research output: Contribution to journalArticlepeer-review

88 Scopus citations


Programmed death-1 (PD-1) is a coinhibitory receptor that downregulates the activity of tumor-infiltrating lymphocytes (TIL) in cancer and of virus-specific T cells in chronic infection. The molecular mechanisms driving high PD-1 expression on TILs have not been fully investigated. We demonstrate that TGFβ1 enhances antigen-induced PD-1 expression through SMAD3-dependent, SMAD2-independent transcriptional activation in T cells in vitro and in TILs in vivo. The PD-1 hi subset seen in CD8 + TILs is absent in Smad3-deficient tumor-specific CD8 + TILs, resulting in enhanced cytokine production by TILs and in draining lymph nodes and antitumor activity. In addition to TGFβ1’s previously known effects on T-cell function, our findings suggest that TGFβ1 mediates T-cell suppression via PD-1 upregulation in the tumor microenvironment (TME). They highlight bidirectional cross-talk between effector TILs and TGFβ-producing cells that upregulates multiple components of the PD-1 signaling pathway to inhibit antitumor immunity. SIGNIFICANCE: Engagement of the coinhibitory receptor PD-1 or its ligand, PD-L1, dramatically inhibits the antitumor function of TILs within the TME. Our findings represent a novel immunosuppressive function of TGFβ and demonstrate that TGFβ1 allows tumors to evade host immune responses in part through enhanced SMAD3-mediated PD-1 expression on TILs.

Original languageEnglish (US)
Pages (from-to)1366-1381
Number of pages16
JournalCancer discovery
Issue number12
StatePublished - Dec 2016

ASJC Scopus subject areas

  • Oncology


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