Anti-PD-L1/TGFβR2 (M7824) fusion protein induces immunogenic modulation of human urothelial carcinoma cell lines, rendering them more susceptible to immune-mediated recognition and lysis

Urol Oncol. 2018 Mar;36(3):93.e1-93.e11. doi: 10.1016/j.urolonc.2017.09.027. Epub 2017 Nov 2.


Background: Avelumab has recently been approved by the Food and Drug Administration for the therapy of Merkel cell carcinoma and urothelial carcinoma. M7824 is a novel first-in-class bifunctional fusion protein comprising a monoclonal antibody against programmed death-ligand 1 (PD-L1, avelumab), fused to the extracellular domain of human transforming growth factor beta (TGFβ) receptor 2, which functions as a TGFβ "trap." Advanced urothelial tumors have been shown to express TGFβ, which possesses immunosuppressive properties that promote cancer progression and metastasis. The rationale for a combined molecule is to block the PD-1/PD-L1 interaction between tumor cells and immune cell infiltrate and simultaneously reduce or eliminate TGFβ from the tumor microenvironment. In this study, we explored the effect of M7824 on invasive urothelial carcinoma cell lines.

Methods: Human urothelial (transitional cell) carcinoma cell lines HTB-4, HTB-1, and HTB-5 were treated with M7824, M7824mut (M7824 that is mutated in the anti-PD-L1 portion of the molecule and thus does not bind PD-L1), anti-PD-L1 (avelumab), or IgG1 isotype control monoclonal antibody, and were assessed for gene expression, cell-surface phenotype, and sensitivity to lysis by TRAIL, antigen-specific cytotoxic T lymphocytes and natural killer cells.

Results: M7824 retains the ability to mediate antibody-dependent cellular cytotoxicity of tumor cells, although in some cases to a lesser extent than anti-PD-L1. However, compared to anti-PD-L1, M7824 increases (A) gene expression of molecules involved in T-cell trafficking in the tumor (e.g., CXCL11), (B) TRAIL-mediated tumor cell lysis, and (C) antigen-specific CD8+ T-cell-mediated lysis of tumor cells.

Conclusions: These studies demonstrate the immunomodulatory properties of M7824 on both tumor cell phenotype and immune-mediated lysis. Compared to anti-PD-L1 or M7824mut, M7824 induces immunogenic modulation of urothelial carcinoma cell lines, rendering them more susceptible to immune-mediated recognition and lysis. These findings show the relevance of the dual blockade of PD-L1 and TGFβ in urothelial carcinoma cell lines and thus support the rationale for future clinical studies of M7824 in patients with urothelial cancer.

Keywords: Anti-PD-L1; Antibody-dependent cellular cytotoxicity; Bladder cancer; CTL-mediated lysis; Immunogenic modulation; TGFβ.

Publication types

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

MeSH terms

  • Antibodies, Monoclonal / genetics
  • Antibodies, Monoclonal / pharmacology
  • Antibodies, Monoclonal / therapeutic use
  • Antibodies, Monoclonal, Humanized
  • Antibody-Dependent Cell Cytotoxicity / drug effects
  • Antibody-Dependent Cell Cytotoxicity / immunology
  • Antineoplastic Agents / therapeutic use*
  • B7-H1 Antigen / antagonists & inhibitors
  • B7-H1 Antigen / metabolism
  • Carcinoma, Transitional Cell / drug therapy*
  • Carcinoma, Transitional Cell / immunology
  • Carcinoma, Transitional Cell / pathology
  • Cell Line, Tumor
  • Drug Evaluation, Preclinical
  • Humans
  • Killer Cells, Natural / drug effects
  • Killer Cells, Natural / immunology
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / pharmacology
  • Protein Serine-Threonine Kinases / therapeutic use
  • Receptor, Transforming Growth Factor-beta Type II
  • Receptors, Transforming Growth Factor beta / genetics
  • Receptors, Transforming Growth Factor beta / therapeutic use
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / pharmacology*
  • Recombinant Fusion Proteins / therapeutic use
  • T-Lymphocytes, Cytotoxic / drug effects
  • T-Lymphocytes, Cytotoxic / immunology
  • Tumor Microenvironment / drug effects
  • Tumor Microenvironment / immunology
  • Urologic Neoplasms / drug therapy*
  • Urologic Neoplasms / immunology
  • Urologic Neoplasms / pathology


  • Antibodies, Monoclonal
  • Antibodies, Monoclonal, Humanized
  • Antineoplastic Agents
  • B7-H1 Antigen
  • CD274 protein, human
  • Receptors, Transforming Growth Factor beta
  • Recombinant Fusion Proteins
  • Protein Serine-Threonine Kinases
  • Receptor, Transforming Growth Factor-beta Type II
  • avelumab