Anti-CD70 immunocytokines for exploitation of interferon-γ-induced RIP1-dependent necrosis in renal cell carcinoma

PLoS One. 2013 Apr 17;8(4):e61446. doi: 10.1371/journal.pone.0061446. Print 2013.

Abstract

Metastatic renal cell carcinoma (RCC) is an incurable disease in clear need of new therapeutic interventions. In early-phase clinical trials, the cytokine IFN-γ showed promise as a biotherapeutic for advanced RCC, but subsequent trials were less promising. These trials, however, focused on the indirect immunomodulatory properties of IFN-γ, and its direct anti-tumor effects, including its ability to kill tumor cells, remains mostly unexploited. We have previously shown that IFN-γ induces RIP1 kinase-dependent necrosis in cells lacking NF-κB survival signaling. RCC cells display basally-elevated NF-κB activity, and inhibiting NF-κB in these cells, for example by using the small-molecule proteasome blocker bortezomib, sensitizes them to RIP1-dependent necrotic death following exposure to IFN-γ. While these observations suggest that IFN-γ-mediated direct tumoricidal activity will have therapeutic benefit in RCC, they cannot be effectively exploited unless IFN-γ is targeted to tumor cells in vivo. Here, we describe the generation and characterization of two novel 'immunocytokine' chimeric proteins, in which either human or murine IFN-γ is fused to an antibody targeting the putative metastatic RCC biomarker CD70. These immunocytokines display high levels of species-specific IFN-γ activity and selective binding to CD70 on human RCC cells. Importantly, the IFN-γ immunocytokines function as well as native IFN-γ in inducing RIP1-dependent necrosis in RCC cells, when deployed in the presence of bortezomib. These results provide a foundation for the in vivo exploitation of IFN-γ-driven tumoricidal activity in RCC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antiviral Agents / pharmacology
  • Boronic Acids / pharmacology
  • Bortezomib
  • CD27 Ligand / antagonists & inhibitors*
  • CD27 Ligand / metabolism
  • Carcinoma, Renal Cell / enzymology
  • Carcinoma, Renal Cell / pathology*
  • Cell Death / drug effects
  • Cell Line, Tumor
  • Humans
  • Interferon-gamma / pharmacology*
  • Kidney Neoplasms / enzymology
  • Kidney Neoplasms / pathology*
  • Mice
  • Necrosis
  • Phosphorylation / drug effects
  • Protein Binding / drug effects
  • Pyrazines / pharmacology
  • Receptor-Interacting Protein Serine-Threonine Kinases / metabolism*
  • Recombinant Fusion Proteins / pharmacology*
  • STAT1 Transcription Factor / metabolism
  • Signal Transduction / drug effects
  • Species Specificity

Substances

  • Antiviral Agents
  • Boronic Acids
  • CD27 Ligand
  • Pyrazines
  • Recombinant Fusion Proteins
  • STAT1 Transcription Factor
  • Bortezomib
  • Interferon-gamma
  • RIPK1 protein, human
  • Receptor-Interacting Protein Serine-Threonine Kinases