Engineered human Tmpk fused with truncated cell-surface markers: versatile cell-fate control safety cassettes

Gene Ther. 2013 Jan;20(1):24-34. doi: 10.1038/gt.2011.210. Epub 2012 Jan 12.

Abstract

Cell-fate control gene therapy (CFCGT)-based strategies can augment existing gene therapy and cell transplantation approaches by providing a safety element in the event of deleterious outcomes. Previously, we described a novel enzyme/prodrug combination for CFCGT. Here, we present results employing novel lentiviral constructs harboring sequences for truncated surface molecules (CD19 or low-affinity nerve growth factor receptor) directly fused to that CFCGT cDNA (TmpkF105Y). This confers an enforced one-to-one correlation between cell marking and eradication functions. In-vitro analysis demonstrated the full functionality of the fusion product. Next, low-dose 3'-azido-3'-deoxythymidine (AZT) administration to non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mice injected with transduced clonal K562 cells suppressed tumor growth; furthermore, one integrated vector on average was sufficient to mediate cytotoxicity. Further, in a murine xenogeneic leukemia-lymphoma model we also demonstrated in-vivo control over transduced Raji cells. Finally, in a proof-of-principle study to examine the utility of this cassette in combination with a therapeutic cDNA, we integrated this novel CFCGT fusion construct into a lentivector designed for treatment of Fabry disease. Transduction with this vector restored enzyme activity in Fabry cells and retained AZT sensitivity. In addition, human Fabry patient CD34(+) cells showed high transduction efficiencies and retained normal colony-generating capacity when compared with the non-transduced controls. These collective results demonstrated that this novel and broadly applicable fusion system may enhance general safety in gene- and cell-based therapies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, CD19 / genetics*
  • Cell Death / drug effects
  • Cell Death / genetics
  • Cell Line, Tumor
  • Fabry Disease / genetics
  • Genetic Vectors
  • HEK293 Cells
  • Humans
  • Lentivirus / genetics
  • Leukemia-Lymphoma, Adult T-Cell / genetics
  • Mice
  • Mice, Inbred NOD
  • Mice, SCID
  • Nucleoside-Phosphate Kinase / genetics*
  • Protein Engineering
  • Receptor, Nerve Growth Factor / genetics*
  • Recombinant Fusion Proteins / genetics
  • Transformation, Genetic
  • Zidovudine / toxicity

Substances

  • Antigens, CD19
  • Receptor, Nerve Growth Factor
  • Recombinant Fusion Proteins
  • Zidovudine
  • Nucleoside-Phosphate Kinase
  • dTMP kinase