Double‐inducible gene activation system for caspase 3 and 9 in epidermis

Abstract

SummaryExpression of genes with tight and precise temporal and spatial control is desired in a wide variety of applications ranging from cultured cells and transgenic animals to gene therapy. While current inducible systems, such as RU486 and chemical inducers of dimerization (CID), have improved earlier inducible models (Gossen et al., 1995) (Wang et al., 1994), no single system is perfect at present. One potential drawback of these systems is leakage of transgene expression, causing limitations of each system. We have developed an inducible model containing both RU486 and CID systems, which in addition to inducing caspase activation, has potential applicability specifically to other genes encoding proteins that require a dimerization event for activation. This Double-Inducible Gene Activation System generates two barriers for the target gene expression and protein activation thereby minimizing leakage.

Exploiting Cell Death Pathways for Inducible Cell Elimination to Modulate Graft-versus-Host-Disease

“…Additionally, co-expression of an initiator caspase (e.g., caspase-9) with an executioner caspase, such as caspase-3, could result in a synergistic/additive effect by providing a higher amount of downstream activatable substrate [62]. Deleting endogenous pro-domain(s) could be more problematic in molecules for which their truncated form would be expected to lead to spontaneous dimerization and activation of cell death pathways, as has been demonstrated for some isoforms of truncated BAX [72].…”

“…Other systems soon followed. These included the use of the death effector domain of FADD [ 58 , 59 ], iC1 [ 58 , 60 , 61 ], iC3 [ 58 , 62 ], iC8 [ 63 ], ΔiC8 [ 58 , 61 , 64 , 65 , 66 , 67 ], iC9 [ 58 , 68 , 69 ], ΔiC9 [ 61 ] and inducible BAX (iBAX) [ 70 ] with variable efficacy in inducing cell death ranging from 30% to ~90%.…”

“…Different requirements on cleavage and dimerization for each molecule, together with the different design of the transgene constructs, may explain why enforced dimerization of some molecules, such as caspase-3, resulted in inducible cell death in some experiences [ 52 , 53 ], but not in others [ 61 ]. Additionally, co-expression of an initiator caspase (e.g., caspase-9) with an executioner caspase, such as caspase-3, could result in a synergistic/additive effect by providing a higher amount of downstream activatable substrate [ 62 ]. Deleting endogenous pro-domain(s) could be more problematic in molecules for which their truncated form would be expected to lead to spontaneous dimerization and activation of cell death pathways, as has been demonstrated for some isoforms of truncated BAX [ 72 ].…”

Gene Switches for Deliberate Regulation of Transgene Expression: Recent Advances in System Development and Uses

“…To minimize basal transgene expression, another study combined ligand regulation at the transcriptional and protein activity levels [126]. Bigenic mouse lines were generated by breeding a transgenic mouse line that expressed chimeric factor Glp65 under the control of an epidermal-specific keratin 14 promoter (which was used to direct gene expression to the keratinocytes of the basal epidermis and hair follicles) with a transgenic mouse line that carried a GLp65-responsive gene for inducible caspase-3 or caspase-9 precursors.…”

Clinical Applications of Gene Therapy in Head and Neck Cancer

“…This approach has the potential to overcome delivery issues of many current cancer gene therapy strategies possibly due to FasL-mediated bystander killing in adjacent cancer cells ]. Alternative approaches under active clinical development involve delivering pro-apoptotic members of the Bcl-2 family, such as Bax [Adams and Cory 2007] or active caspase molecules [Shah, et al 2007]. …”