Part:BBa_K4421002

iCasp9

iCasp9 is a chemically-inducible kill switch.When exposed to a synthetic dimerizing drug such as AP1903, the inducible caspase 9 (iCasp9) becomes activated and leads to the rapid death of cells expressing this construct.iCasp9 can be activated by AP1903 that has proven safe at the required dose for optimum deletional effect

Usage and Biology

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iCasp9 is based on a modified human caspase 9 fused to a human FK506 binding protein (FKBP) to allow conditional dimerization using a small molecule pharmaceutical.When rimiducid(AP1903) is present in the environment,it will dimerizes iCasp9 and activate caspase 3,6,7. Finally, apoptosis is induced.

iCasp9 consists of the sequence of the human FK506-binding protein (FKBP12; GenBank number, AH002818) with an F36V mutation, connected through a Ser-Gly-Gly-Gly-Ser linker to the gene encoding human caspase 9 (CASP9; GenBank number, NM001229), which is deleted for its endogenous caspase activation and recruitment domain. (Di Stasi et al., 2011)

A single 10-nM dose of synthetic dimerizer drug induces apoptosis in 99% of transduced cells selected for high transgene expression in vitro and in vivo.

This system has several advantages over currently available suicide genes. First, it consists of human gene products with low potential immunogenicity. Second, administration of dimerizer drug has no effects other than the selective elimination of transduced T cells. Third, inducible caspase 9 maintains function in T cells overexpressing antiapoptotic molecules. These characteristics favor incorporation of inducible caspase 9 as a safety feature in human T-cell therapies. (Straathof et al., 2005)

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  INCOMPATIBLE WITH RFC[21]

  Illegal BamHI site found at 331
  
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  INCOMPATIBLE WITH RFC[1000]

  Illegal BsaI.rc site found at 13
  Illegal BsaI.rc site found at 1153
  

References

Di Stasi, A., Tey, S.-K., Dotti, G., Fujita, Y., Kennedy-Nasser, A., Martinez, C., Straathof, K., Liu, E., Durett, A. G., Grilley, B., Liu, H., Cruz, C. R., Savoldo, B., Gee, A. P., Schindler, J., Krance, R. A., Heslop, H. E., Spencer, D. M., Rooney, C. M., & Brenner, M. K. (2011). Inducible Apoptosis as a Safety Switch for Adoptive Cell Therapy. The New England Journal of Medicine, 365(18), 1673–1683. https://doi.org/10.1056/NEJMoa1106152

Straathof, K. C., Pulè, M. A., Yotnda, P., Dotti, G., Vanin, E. F., Brenner, M. K., Heslop, H. E., Spencer, D. M., & Rooney, C. M. (2005). An inducible caspase 9 safety switch for T-cell therapy. Blood, 105(11), 4247–4254. https://doi.org/10.1182/blood-2004-11-4564