Progress toward the genetic treatment of the beta-thalassemias

Ann N Y Acad Sci. 2005;1054:78-91. doi: 10.1196/annals.1345.010.

Abstract

The beta-thalassemias are congenital anemias that are caused by mutations that reduce or abolish expression of the beta-globin gene. They can be cured by allogeneic hematopoietic stem cell (HSC) transplantation, but this therapeutic option is not available to most patients. The transfer of a regulated beta-globin gene in autologous HSCs is a highly attractive alternative treatment. This strategy, which is simple in principle, raises major challenges in terms of controlling expression of the globin transgene, which ideally should be erythroid specific, differentiation- and stage-restricted, elevated, position independent, and sustained over time. Using lentiviral vectors, May et al. demonstrated in 2000 that an optimized combination of proximal and distal transcriptional control elements permits lineage-specific and elevated beta-globin expression, resulting in therapeutic hemoglobin production and correction of anemia in beta-thalassemic mice. Several groups have by now replicated and extended these findings to various mouse models of severe hemoglobinopathies, thus fueling enthusiasm for a potential treatment of beta-thalassemia based on globin gene transfer. Current investigation focuses on safety issues and the need for improved vector production methodologies. The safe implementation of stem cell-based gene therapy requires the prevention of the formation of replication-competent viral genomes and minimization of the risk of insertional oncogenesis. Importantly, globin vectors, in which transcriptional activity is highly restricted, have a lesser risk of activating oncogenes in hematopoietic progenitors than non-tissue-specific vectors, by virtue of their late-stage erythroid specificity. As such, they provide a general paradigm for improving vector safety in stem cell-based gene therapy.

Publication types

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

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Animals
  • DNA-Binding Proteins / genetics
  • Disease Models, Animal
  • Gene Expression Regulation, Viral
  • Gene Silencing
  • Gene Transfer Techniques
  • Genetic Therapy* / adverse effects
  • Genetic Vectors / adverse effects
  • Genetic Vectors / therapeutic use
  • Globins / biosynthesis
  • Globins / genetics*
  • HIV-1 / genetics
  • Hematopoietic Stem Cell Transplantation
  • Humans
  • LIM Domain Proteins
  • Lentivirus / genetics
  • Leukemia, Lymphoid / etiology
  • Locus Control Region / genetics
  • Metalloproteins / genetics
  • Mice
  • Mice, Inbred C57BL
  • Mice, Mutant Strains
  • Mice, Transgenic
  • Mutagenesis, Insertional
  • Oncogenes
  • Proto-Oncogene Proteins
  • Retroviridae / genetics
  • Severe Combined Immunodeficiency / genetics
  • Severe Combined Immunodeficiency / therapy
  • Terminal Repeat Sequences
  • Transgenes
  • beta-Thalassemia / therapy*

Substances

  • Adaptor Proteins, Signal Transducing
  • DNA-Binding Proteins
  • LIM Domain Proteins
  • LMO2 protein, human
  • Lmo2 protein, mouse
  • Metalloproteins
  • Proto-Oncogene Proteins
  • Globins